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230d793d | 1 | /* Optimize by combining instructions for GNU compiler. |
0c314d1a | 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994 Free Software Foundation, Inc. |
230d793d RS |
3 | |
4 | This file is part of GNU CC. | |
5 | ||
6 | GNU CC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU CC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU CC; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | ||
21 | /* This module is essentially the "combiner" phase of the U. of Arizona | |
22 | Portable Optimizer, but redone to work on our list-structured | |
23 | representation for RTL instead of their string representation. | |
24 | ||
25 | The LOG_LINKS of each insn identify the most recent assignment | |
26 | to each REG used in the insn. It is a list of previous insns, | |
27 | each of which contains a SET for a REG that is used in this insn | |
28 | and not used or set in between. LOG_LINKs never cross basic blocks. | |
29 | They were set up by the preceding pass (lifetime analysis). | |
30 | ||
31 | We try to combine each pair of insns joined by a logical link. | |
32 | We also try to combine triples of insns A, B and C when | |
33 | C has a link back to B and B has a link back to A. | |
34 | ||
35 | LOG_LINKS does not have links for use of the CC0. They don't | |
36 | need to, because the insn that sets the CC0 is always immediately | |
37 | before the insn that tests it. So we always regard a branch | |
38 | insn as having a logical link to the preceding insn. The same is true | |
39 | for an insn explicitly using CC0. | |
40 | ||
41 | We check (with use_crosses_set_p) to avoid combining in such a way | |
42 | as to move a computation to a place where its value would be different. | |
43 | ||
44 | Combination is done by mathematically substituting the previous | |
45 | insn(s) values for the regs they set into the expressions in | |
46 | the later insns that refer to these regs. If the result is a valid insn | |
47 | for our target machine, according to the machine description, | |
48 | we install it, delete the earlier insns, and update the data flow | |
49 | information (LOG_LINKS and REG_NOTES) for what we did. | |
50 | ||
51 | There are a few exceptions where the dataflow information created by | |
52 | flow.c aren't completely updated: | |
53 | ||
54 | - reg_live_length is not updated | |
55 | - reg_n_refs is not adjusted in the rare case when a register is | |
56 | no longer required in a computation | |
57 | - there are extremely rare cases (see distribute_regnotes) when a | |
58 | REG_DEAD note is lost | |
59 | - a LOG_LINKS entry that refers to an insn with multiple SETs may be | |
60 | removed because there is no way to know which register it was | |
61 | linking | |
62 | ||
63 | To simplify substitution, we combine only when the earlier insn(s) | |
64 | consist of only a single assignment. To simplify updating afterward, | |
65 | we never combine when a subroutine call appears in the middle. | |
66 | ||
67 | Since we do not represent assignments to CC0 explicitly except when that | |
68 | is all an insn does, there is no LOG_LINKS entry in an insn that uses | |
69 | the condition code for the insn that set the condition code. | |
70 | Fortunately, these two insns must be consecutive. | |
71 | Therefore, every JUMP_INSN is taken to have an implicit logical link | |
72 | to the preceding insn. This is not quite right, since non-jumps can | |
73 | also use the condition code; but in practice such insns would not | |
74 | combine anyway. */ | |
75 | ||
230d793d | 76 | #include "config.h" |
4f90e4a0 | 77 | #ifdef __STDC__ |
04fe4385 | 78 | #include <stdarg.h> |
4f90e4a0 | 79 | #else |
04fe4385 | 80 | #include <varargs.h> |
4f90e4a0 | 81 | #endif |
dfa3449b | 82 | |
9c3b4c8b RS |
83 | /* Must precede rtl.h for FFS. */ |
84 | #include <stdio.h> | |
85 | ||
230d793d RS |
86 | #include "rtl.h" |
87 | #include "flags.h" | |
88 | #include "regs.h" | |
55310dad | 89 | #include "hard-reg-set.h" |
230d793d RS |
90 | #include "expr.h" |
91 | #include "basic-block.h" | |
92 | #include "insn-config.h" | |
93 | #include "insn-flags.h" | |
94 | #include "insn-codes.h" | |
95 | #include "insn-attr.h" | |
96 | #include "recog.h" | |
97 | #include "real.h" | |
98 | ||
99 | /* It is not safe to use ordinary gen_lowpart in combine. | |
100 | Use gen_lowpart_for_combine instead. See comments there. */ | |
101 | #define gen_lowpart dont_use_gen_lowpart_you_dummy | |
102 | ||
103 | /* Number of attempts to combine instructions in this function. */ | |
104 | ||
105 | static int combine_attempts; | |
106 | ||
107 | /* Number of attempts that got as far as substitution in this function. */ | |
108 | ||
109 | static int combine_merges; | |
110 | ||
111 | /* Number of instructions combined with added SETs in this function. */ | |
112 | ||
113 | static int combine_extras; | |
114 | ||
115 | /* Number of instructions combined in this function. */ | |
116 | ||
117 | static int combine_successes; | |
118 | ||
119 | /* Totals over entire compilation. */ | |
120 | ||
121 | static int total_attempts, total_merges, total_extras, total_successes; | |
9210df58 RK |
122 | |
123 | /* Define a defulat value for REVERSIBLE_CC_MODE. | |
124 | We can never assume that a condition code mode is safe to reverse unless | |
125 | the md tells us so. */ | |
126 | #ifndef REVERSIBLE_CC_MODE | |
127 | #define REVERSIBLE_CC_MODE(MODE) 0 | |
128 | #endif | |
230d793d RS |
129 | \f |
130 | /* Vector mapping INSN_UIDs to cuids. | |
5089e22e | 131 | The cuids are like uids but increase monotonically always. |
230d793d RS |
132 | Combine always uses cuids so that it can compare them. |
133 | But actually renumbering the uids, which we used to do, | |
134 | proves to be a bad idea because it makes it hard to compare | |
135 | the dumps produced by earlier passes with those from later passes. */ | |
136 | ||
137 | static int *uid_cuid; | |
138 | ||
139 | /* Get the cuid of an insn. */ | |
140 | ||
141 | #define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)]) | |
142 | ||
143 | /* Maximum register number, which is the size of the tables below. */ | |
144 | ||
145 | static int combine_max_regno; | |
146 | ||
147 | /* Record last point of death of (hard or pseudo) register n. */ | |
148 | ||
149 | static rtx *reg_last_death; | |
150 | ||
151 | /* Record last point of modification of (hard or pseudo) register n. */ | |
152 | ||
153 | static rtx *reg_last_set; | |
154 | ||
155 | /* Record the cuid of the last insn that invalidated memory | |
156 | (anything that writes memory, and subroutine calls, but not pushes). */ | |
157 | ||
158 | static int mem_last_set; | |
159 | ||
160 | /* Record the cuid of the last CALL_INSN | |
161 | so we can tell whether a potential combination crosses any calls. */ | |
162 | ||
163 | static int last_call_cuid; | |
164 | ||
165 | /* When `subst' is called, this is the insn that is being modified | |
166 | (by combining in a previous insn). The PATTERN of this insn | |
167 | is still the old pattern partially modified and it should not be | |
168 | looked at, but this may be used to examine the successors of the insn | |
169 | to judge whether a simplification is valid. */ | |
170 | ||
171 | static rtx subst_insn; | |
172 | ||
173 | /* This is the lowest CUID that `subst' is currently dealing with. | |
174 | get_last_value will not return a value if the register was set at or | |
175 | after this CUID. If not for this mechanism, we could get confused if | |
176 | I2 or I1 in try_combine were an insn that used the old value of a register | |
177 | to obtain a new value. In that case, we might erroneously get the | |
178 | new value of the register when we wanted the old one. */ | |
179 | ||
180 | static int subst_low_cuid; | |
181 | ||
6e25d159 RK |
182 | /* This contains any hard registers that are used in newpat; reg_dead_at_p |
183 | must consider all these registers to be always live. */ | |
184 | ||
185 | static HARD_REG_SET newpat_used_regs; | |
186 | ||
abe6e52f RK |
187 | /* This is an insn to which a LOG_LINKS entry has been added. If this |
188 | insn is the earlier than I2 or I3, combine should rescan starting at | |
189 | that location. */ | |
190 | ||
191 | static rtx added_links_insn; | |
192 | ||
230d793d RS |
193 | /* This is the value of undobuf.num_undo when we started processing this |
194 | substitution. This will prevent gen_rtx_combine from re-used a piece | |
195 | from the previous expression. Doing so can produce circular rtl | |
196 | structures. */ | |
197 | ||
198 | static int previous_num_undos; | |
ca5c3ef4 | 199 | |
0d4d42c3 RK |
200 | /* Basic block number of the block in which we are performing combines. */ |
201 | static int this_basic_block; | |
230d793d RS |
202 | \f |
203 | /* The next group of arrays allows the recording of the last value assigned | |
204 | to (hard or pseudo) register n. We use this information to see if a | |
5089e22e | 205 | operation being processed is redundant given a prior operation performed |
230d793d RS |
206 | on the register. For example, an `and' with a constant is redundant if |
207 | all the zero bits are already known to be turned off. | |
208 | ||
209 | We use an approach similar to that used by cse, but change it in the | |
210 | following ways: | |
211 | ||
212 | (1) We do not want to reinitialize at each label. | |
213 | (2) It is useful, but not critical, to know the actual value assigned | |
214 | to a register. Often just its form is helpful. | |
215 | ||
216 | Therefore, we maintain the following arrays: | |
217 | ||
218 | reg_last_set_value the last value assigned | |
219 | reg_last_set_label records the value of label_tick when the | |
220 | register was assigned | |
221 | reg_last_set_table_tick records the value of label_tick when a | |
222 | value using the register is assigned | |
223 | reg_last_set_invalid set to non-zero when it is not valid | |
224 | to use the value of this register in some | |
225 | register's value | |
226 | ||
227 | To understand the usage of these tables, it is important to understand | |
228 | the distinction between the value in reg_last_set_value being valid | |
229 | and the register being validly contained in some other expression in the | |
230 | table. | |
231 | ||
232 | Entry I in reg_last_set_value is valid if it is non-zero, and either | |
233 | reg_n_sets[i] is 1 or reg_last_set_label[i] == label_tick. | |
234 | ||
235 | Register I may validly appear in any expression returned for the value | |
236 | of another register if reg_n_sets[i] is 1. It may also appear in the | |
237 | value for register J if reg_last_set_label[i] < reg_last_set_label[j] or | |
238 | reg_last_set_invalid[j] is zero. | |
239 | ||
240 | If an expression is found in the table containing a register which may | |
241 | not validly appear in an expression, the register is replaced by | |
242 | something that won't match, (clobber (const_int 0)). | |
243 | ||
244 | reg_last_set_invalid[i] is set non-zero when register I is being assigned | |
245 | to and reg_last_set_table_tick[i] == label_tick. */ | |
246 | ||
247 | /* Record last value assigned to (hard or pseudo) register n. */ | |
248 | ||
249 | static rtx *reg_last_set_value; | |
250 | ||
251 | /* Record the value of label_tick when the value for register n is placed in | |
252 | reg_last_set_value[n]. */ | |
253 | ||
568356af | 254 | static int *reg_last_set_label; |
230d793d RS |
255 | |
256 | /* Record the value of label_tick when an expression involving register n | |
257 | is placed in reg_last_set_value. */ | |
258 | ||
568356af | 259 | static int *reg_last_set_table_tick; |
230d793d RS |
260 | |
261 | /* Set non-zero if references to register n in expressions should not be | |
262 | used. */ | |
263 | ||
264 | static char *reg_last_set_invalid; | |
265 | ||
266 | /* Incremented for each label. */ | |
267 | ||
568356af | 268 | static int label_tick; |
230d793d RS |
269 | |
270 | /* Some registers that are set more than once and used in more than one | |
271 | basic block are nevertheless always set in similar ways. For example, | |
272 | a QImode register may be loaded from memory in two places on a machine | |
273 | where byte loads zero extend. | |
274 | ||
951553af | 275 | We record in the following array what we know about the nonzero |
230d793d RS |
276 | bits of a register, specifically which bits are known to be zero. |
277 | ||
278 | If an entry is zero, it means that we don't know anything special. */ | |
279 | ||
55310dad | 280 | static unsigned HOST_WIDE_INT *reg_nonzero_bits; |
230d793d | 281 | |
951553af | 282 | /* Mode used to compute significance in reg_nonzero_bits. It is the largest |
5f4f0e22 | 283 | integer mode that can fit in HOST_BITS_PER_WIDE_INT. */ |
230d793d | 284 | |
951553af | 285 | static enum machine_mode nonzero_bits_mode; |
230d793d | 286 | |
d0ab8cd3 RK |
287 | /* Nonzero if we know that a register has some leading bits that are always |
288 | equal to the sign bit. */ | |
289 | ||
290 | static char *reg_sign_bit_copies; | |
291 | ||
951553af | 292 | /* Nonzero when reg_nonzero_bits and reg_sign_bit_copies can be safely used. |
1a26b032 RK |
293 | It is zero while computing them and after combine has completed. This |
294 | former test prevents propagating values based on previously set values, | |
295 | which can be incorrect if a variable is modified in a loop. */ | |
230d793d | 296 | |
951553af | 297 | static int nonzero_sign_valid; |
55310dad RK |
298 | |
299 | /* These arrays are maintained in parallel with reg_last_set_value | |
300 | and are used to store the mode in which the register was last set, | |
301 | the bits that were known to be zero when it was last set, and the | |
302 | number of sign bits copies it was known to have when it was last set. */ | |
303 | ||
304 | static enum machine_mode *reg_last_set_mode; | |
305 | static unsigned HOST_WIDE_INT *reg_last_set_nonzero_bits; | |
306 | static char *reg_last_set_sign_bit_copies; | |
230d793d RS |
307 | \f |
308 | /* Record one modification to rtl structure | |
309 | to be undone by storing old_contents into *where. | |
310 | is_int is 1 if the contents are an int. */ | |
311 | ||
312 | struct undo | |
313 | { | |
230d793d | 314 | int is_int; |
f5393ab9 RS |
315 | union {rtx r; int i;} old_contents; |
316 | union {rtx *r; int *i;} where; | |
230d793d RS |
317 | }; |
318 | ||
319 | /* Record a bunch of changes to be undone, up to MAX_UNDO of them. | |
320 | num_undo says how many are currently recorded. | |
321 | ||
322 | storage is nonzero if we must undo the allocation of new storage. | |
323 | The value of storage is what to pass to obfree. | |
324 | ||
325 | other_insn is nonzero if we have modified some other insn in the process | |
326 | of working on subst_insn. It must be verified too. */ | |
327 | ||
328 | #define MAX_UNDO 50 | |
329 | ||
330 | struct undobuf | |
331 | { | |
332 | int num_undo; | |
333 | char *storage; | |
334 | struct undo undo[MAX_UNDO]; | |
335 | rtx other_insn; | |
336 | }; | |
337 | ||
338 | static struct undobuf undobuf; | |
339 | ||
cc876596 | 340 | /* Substitute NEWVAL, an rtx expression, into INTO, a place in some |
230d793d | 341 | insn. The substitution can be undone by undo_all. If INTO is already |
cc876596 RK |
342 | set to NEWVAL, do not record this change. Because computing NEWVAL might |
343 | also call SUBST, we have to compute it before we put anything into | |
344 | the undo table. */ | |
230d793d RS |
345 | |
346 | #define SUBST(INTO, NEWVAL) \ | |
cc876596 RK |
347 | do { rtx _new = (NEWVAL); \ |
348 | if (undobuf.num_undo < MAX_UNDO) \ | |
230d793d | 349 | { \ |
230d793d | 350 | undobuf.undo[undobuf.num_undo].is_int = 0; \ |
f5393ab9 RS |
351 | undobuf.undo[undobuf.num_undo].where.r = &INTO; \ |
352 | undobuf.undo[undobuf.num_undo].old_contents.r = INTO; \ | |
cc876596 | 353 | INTO = _new; \ |
f5393ab9 | 354 | if (undobuf.undo[undobuf.num_undo].old_contents.r != INTO) \ |
230d793d RS |
355 | undobuf.num_undo++; \ |
356 | } \ | |
357 | } while (0) | |
358 | ||
359 | /* Similar to SUBST, but NEWVAL is an int. INTO will normally be an XINT | |
360 | expression. | |
361 | Note that substitution for the value of a CONST_INT is not safe. */ | |
362 | ||
363 | #define SUBST_INT(INTO, NEWVAL) \ | |
364 | do { if (undobuf.num_undo < MAX_UNDO) \ | |
365 | { \ | |
7c046e4e RK |
366 | undobuf.undo[undobuf.num_undo].is_int = 1; \ |
367 | undobuf.undo[undobuf.num_undo].where.i = (int *) &INTO; \ | |
368 | undobuf.undo[undobuf.num_undo].old_contents.i = INTO; \ | |
230d793d | 369 | INTO = NEWVAL; \ |
7c046e4e | 370 | if (undobuf.undo[undobuf.num_undo].old_contents.i != INTO) \ |
230d793d RS |
371 | undobuf.num_undo++; \ |
372 | } \ | |
373 | } while (0) | |
374 | ||
375 | /* Number of times the pseudo being substituted for | |
376 | was found and replaced. */ | |
377 | ||
378 | static int n_occurrences; | |
379 | ||
ef026f91 | 380 | static void init_reg_last_arrays PROTO(()); |
fe2db4fb RK |
381 | static void setup_incoming_promotions PROTO(()); |
382 | static void set_nonzero_bits_and_sign_copies PROTO((rtx, rtx)); | |
383 | static int can_combine_p PROTO((rtx, rtx, rtx, rtx, rtx *, rtx *)); | |
384 | static int combinable_i3pat PROTO((rtx, rtx *, rtx, rtx, int, rtx *)); | |
385 | static rtx try_combine PROTO((rtx, rtx, rtx)); | |
386 | static void undo_all PROTO((void)); | |
387 | static rtx *find_split_point PROTO((rtx *, rtx)); | |
388 | static rtx subst PROTO((rtx, rtx, rtx, int, int)); | |
8079805d RK |
389 | static rtx simplify_rtx PROTO((rtx, enum machine_mode, int, int)); |
390 | static rtx simplify_if_then_else PROTO((rtx)); | |
391 | static rtx simplify_set PROTO((rtx)); | |
392 | static rtx simplify_logical PROTO((rtx, int)); | |
fe2db4fb RK |
393 | static rtx expand_compound_operation PROTO((rtx)); |
394 | static rtx expand_field_assignment PROTO((rtx)); | |
395 | static rtx make_extraction PROTO((enum machine_mode, rtx, int, rtx, int, | |
396 | int, int, int)); | |
71923da7 | 397 | static rtx extract_left_shift PROTO((rtx, int)); |
fe2db4fb RK |
398 | static rtx make_compound_operation PROTO((rtx, enum rtx_code)); |
399 | static int get_pos_from_mask PROTO((unsigned HOST_WIDE_INT, int *)); | |
6139ff20 | 400 | static rtx force_to_mode PROTO((rtx, enum machine_mode, |
e3d616e3 | 401 | unsigned HOST_WIDE_INT, rtx, int)); |
abe6e52f | 402 | static rtx if_then_else_cond PROTO((rtx, rtx *, rtx *)); |
fe2db4fb RK |
403 | static rtx known_cond PROTO((rtx, enum rtx_code, rtx, rtx)); |
404 | static rtx make_field_assignment PROTO((rtx)); | |
405 | static rtx apply_distributive_law PROTO((rtx)); | |
406 | static rtx simplify_and_const_int PROTO((rtx, enum machine_mode, rtx, | |
407 | unsigned HOST_WIDE_INT)); | |
408 | static unsigned HOST_WIDE_INT nonzero_bits PROTO((rtx, enum machine_mode)); | |
409 | static int num_sign_bit_copies PROTO((rtx, enum machine_mode)); | |
410 | static int merge_outer_ops PROTO((enum rtx_code *, HOST_WIDE_INT *, | |
411 | enum rtx_code, HOST_WIDE_INT, | |
412 | enum machine_mode, int *)); | |
413 | static rtx simplify_shift_const PROTO((rtx, enum rtx_code, enum machine_mode, | |
414 | rtx, int)); | |
415 | static int recog_for_combine PROTO((rtx *, rtx, rtx *)); | |
416 | static rtx gen_lowpart_for_combine PROTO((enum machine_mode, rtx)); | |
d18225c4 | 417 | static rtx gen_rtx_combine PVPROTO((enum rtx_code code, enum machine_mode mode, |
4f90e4a0 | 418 | ...)); |
fe2db4fb RK |
419 | static rtx gen_binary PROTO((enum rtx_code, enum machine_mode, |
420 | rtx, rtx)); | |
0c1c8ea6 RK |
421 | static rtx gen_unary PROTO((enum rtx_code, enum machine_mode, |
422 | enum machine_mode, rtx)); | |
fe2db4fb RK |
423 | static enum rtx_code simplify_comparison PROTO((enum rtx_code, rtx *, rtx *)); |
424 | static int reversible_comparison_p PROTO((rtx)); | |
425 | static void update_table_tick PROTO((rtx)); | |
426 | static void record_value_for_reg PROTO((rtx, rtx, rtx)); | |
427 | static void record_dead_and_set_regs_1 PROTO((rtx, rtx)); | |
428 | static void record_dead_and_set_regs PROTO((rtx)); | |
429 | static int get_last_value_validate PROTO((rtx *, int, int)); | |
430 | static rtx get_last_value PROTO((rtx)); | |
431 | static int use_crosses_set_p PROTO((rtx, int)); | |
432 | static void reg_dead_at_p_1 PROTO((rtx, rtx)); | |
433 | static int reg_dead_at_p PROTO((rtx, rtx)); | |
434 | static void move_deaths PROTO((rtx, int, rtx, rtx *)); | |
435 | static int reg_bitfield_target_p PROTO((rtx, rtx)); | |
436 | static void distribute_notes PROTO((rtx, rtx, rtx, rtx, rtx, rtx)); | |
437 | static void distribute_links PROTO((rtx)); | |
6e25d159 | 438 | static void mark_used_regs_combine PROTO((rtx)); |
230d793d RS |
439 | \f |
440 | /* Main entry point for combiner. F is the first insn of the function. | |
441 | NREGS is the first unused pseudo-reg number. */ | |
442 | ||
443 | void | |
444 | combine_instructions (f, nregs) | |
445 | rtx f; | |
446 | int nregs; | |
447 | { | |
448 | register rtx insn, next, prev; | |
449 | register int i; | |
450 | register rtx links, nextlinks; | |
451 | ||
452 | combine_attempts = 0; | |
453 | combine_merges = 0; | |
454 | combine_extras = 0; | |
455 | combine_successes = 0; | |
bef9925b | 456 | undobuf.num_undo = previous_num_undos = 0; |
230d793d RS |
457 | |
458 | combine_max_regno = nregs; | |
459 | ||
ef026f91 RS |
460 | reg_nonzero_bits |
461 | = (unsigned HOST_WIDE_INT *) alloca (nregs * sizeof (HOST_WIDE_INT)); | |
462 | reg_sign_bit_copies = (char *) alloca (nregs * sizeof (char)); | |
463 | ||
4c9a05bc | 464 | bzero ((char *) reg_nonzero_bits, nregs * sizeof (HOST_WIDE_INT)); |
ef026f91 RS |
465 | bzero (reg_sign_bit_copies, nregs * sizeof (char)); |
466 | ||
230d793d RS |
467 | reg_last_death = (rtx *) alloca (nregs * sizeof (rtx)); |
468 | reg_last_set = (rtx *) alloca (nregs * sizeof (rtx)); | |
469 | reg_last_set_value = (rtx *) alloca (nregs * sizeof (rtx)); | |
568356af RK |
470 | reg_last_set_table_tick = (int *) alloca (nregs * sizeof (int)); |
471 | reg_last_set_label = (int *) alloca (nregs * sizeof (int)); | |
5f4f0e22 | 472 | reg_last_set_invalid = (char *) alloca (nregs * sizeof (char)); |
55310dad RK |
473 | reg_last_set_mode |
474 | = (enum machine_mode *) alloca (nregs * sizeof (enum machine_mode)); | |
475 | reg_last_set_nonzero_bits | |
476 | = (unsigned HOST_WIDE_INT *) alloca (nregs * sizeof (HOST_WIDE_INT)); | |
477 | reg_last_set_sign_bit_copies | |
478 | = (char *) alloca (nregs * sizeof (char)); | |
479 | ||
ef026f91 | 480 | init_reg_last_arrays (); |
230d793d RS |
481 | |
482 | init_recog_no_volatile (); | |
483 | ||
484 | /* Compute maximum uid value so uid_cuid can be allocated. */ | |
485 | ||
486 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) | |
487 | if (INSN_UID (insn) > i) | |
488 | i = INSN_UID (insn); | |
489 | ||
490 | uid_cuid = (int *) alloca ((i + 1) * sizeof (int)); | |
491 | ||
951553af | 492 | nonzero_bits_mode = mode_for_size (HOST_BITS_PER_WIDE_INT, MODE_INT, 0); |
230d793d | 493 | |
951553af | 494 | /* Don't use reg_nonzero_bits when computing it. This can cause problems |
230d793d RS |
495 | when, for example, we have j <<= 1 in a loop. */ |
496 | ||
951553af | 497 | nonzero_sign_valid = 0; |
230d793d RS |
498 | |
499 | /* Compute the mapping from uids to cuids. | |
500 | Cuids are numbers assigned to insns, like uids, | |
501 | except that cuids increase monotonically through the code. | |
502 | ||
503 | Scan all SETs and see if we can deduce anything about what | |
951553af | 504 | bits are known to be zero for some registers and how many copies |
d79f08e0 RK |
505 | of the sign bit are known to exist for those registers. |
506 | ||
507 | Also set any known values so that we can use it while searching | |
508 | for what bits are known to be set. */ | |
509 | ||
510 | label_tick = 1; | |
230d793d | 511 | |
7988fd36 RK |
512 | setup_incoming_promotions (); |
513 | ||
230d793d RS |
514 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) |
515 | { | |
516 | INSN_CUID (insn) = ++i; | |
d79f08e0 RK |
517 | subst_low_cuid = i; |
518 | subst_insn = insn; | |
519 | ||
230d793d | 520 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
d79f08e0 RK |
521 | { |
522 | note_stores (PATTERN (insn), set_nonzero_bits_and_sign_copies); | |
523 | record_dead_and_set_regs (insn); | |
524 | } | |
525 | ||
526 | if (GET_CODE (insn) == CODE_LABEL) | |
527 | label_tick++; | |
230d793d RS |
528 | } |
529 | ||
951553af | 530 | nonzero_sign_valid = 1; |
230d793d RS |
531 | |
532 | /* Now scan all the insns in forward order. */ | |
533 | ||
0d4d42c3 | 534 | this_basic_block = -1; |
230d793d RS |
535 | label_tick = 1; |
536 | last_call_cuid = 0; | |
537 | mem_last_set = 0; | |
ef026f91 | 538 | init_reg_last_arrays (); |
7988fd36 RK |
539 | setup_incoming_promotions (); |
540 | ||
230d793d RS |
541 | for (insn = f; insn; insn = next ? next : NEXT_INSN (insn)) |
542 | { | |
543 | next = 0; | |
544 | ||
0d4d42c3 | 545 | /* If INSN starts a new basic block, update our basic block number. */ |
f085c9cd | 546 | if (this_basic_block + 1 < n_basic_blocks |
0d4d42c3 RK |
547 | && basic_block_head[this_basic_block + 1] == insn) |
548 | this_basic_block++; | |
549 | ||
230d793d RS |
550 | if (GET_CODE (insn) == CODE_LABEL) |
551 | label_tick++; | |
552 | ||
0d4d42c3 | 553 | else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
230d793d RS |
554 | { |
555 | /* Try this insn with each insn it links back to. */ | |
556 | ||
557 | for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) | |
5f4f0e22 | 558 | if ((next = try_combine (insn, XEXP (links, 0), NULL_RTX)) != 0) |
230d793d RS |
559 | goto retry; |
560 | ||
561 | /* Try each sequence of three linked insns ending with this one. */ | |
562 | ||
563 | for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) | |
564 | for (nextlinks = LOG_LINKS (XEXP (links, 0)); nextlinks; | |
565 | nextlinks = XEXP (nextlinks, 1)) | |
566 | if ((next = try_combine (insn, XEXP (links, 0), | |
567 | XEXP (nextlinks, 0))) != 0) | |
568 | goto retry; | |
569 | ||
570 | #ifdef HAVE_cc0 | |
571 | /* Try to combine a jump insn that uses CC0 | |
572 | with a preceding insn that sets CC0, and maybe with its | |
573 | logical predecessor as well. | |
574 | This is how we make decrement-and-branch insns. | |
575 | We need this special code because data flow connections | |
576 | via CC0 do not get entered in LOG_LINKS. */ | |
577 | ||
578 | if (GET_CODE (insn) == JUMP_INSN | |
579 | && (prev = prev_nonnote_insn (insn)) != 0 | |
580 | && GET_CODE (prev) == INSN | |
581 | && sets_cc0_p (PATTERN (prev))) | |
582 | { | |
5f4f0e22 | 583 | if ((next = try_combine (insn, prev, NULL_RTX)) != 0) |
230d793d RS |
584 | goto retry; |
585 | ||
586 | for (nextlinks = LOG_LINKS (prev); nextlinks; | |
587 | nextlinks = XEXP (nextlinks, 1)) | |
588 | if ((next = try_combine (insn, prev, | |
589 | XEXP (nextlinks, 0))) != 0) | |
590 | goto retry; | |
591 | } | |
592 | ||
593 | /* Do the same for an insn that explicitly references CC0. */ | |
594 | if (GET_CODE (insn) == INSN | |
595 | && (prev = prev_nonnote_insn (insn)) != 0 | |
596 | && GET_CODE (prev) == INSN | |
597 | && sets_cc0_p (PATTERN (prev)) | |
598 | && GET_CODE (PATTERN (insn)) == SET | |
599 | && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN (insn)))) | |
600 | { | |
5f4f0e22 | 601 | if ((next = try_combine (insn, prev, NULL_RTX)) != 0) |
230d793d RS |
602 | goto retry; |
603 | ||
604 | for (nextlinks = LOG_LINKS (prev); nextlinks; | |
605 | nextlinks = XEXP (nextlinks, 1)) | |
606 | if ((next = try_combine (insn, prev, | |
607 | XEXP (nextlinks, 0))) != 0) | |
608 | goto retry; | |
609 | } | |
610 | ||
611 | /* Finally, see if any of the insns that this insn links to | |
612 | explicitly references CC0. If so, try this insn, that insn, | |
5089e22e | 613 | and its predecessor if it sets CC0. */ |
230d793d RS |
614 | for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) |
615 | if (GET_CODE (XEXP (links, 0)) == INSN | |
616 | && GET_CODE (PATTERN (XEXP (links, 0))) == SET | |
617 | && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN (XEXP (links, 0)))) | |
618 | && (prev = prev_nonnote_insn (XEXP (links, 0))) != 0 | |
619 | && GET_CODE (prev) == INSN | |
620 | && sets_cc0_p (PATTERN (prev)) | |
621 | && (next = try_combine (insn, XEXP (links, 0), prev)) != 0) | |
622 | goto retry; | |
623 | #endif | |
624 | ||
625 | /* Try combining an insn with two different insns whose results it | |
626 | uses. */ | |
627 | for (links = LOG_LINKS (insn); links; links = XEXP (links, 1)) | |
628 | for (nextlinks = XEXP (links, 1); nextlinks; | |
629 | nextlinks = XEXP (nextlinks, 1)) | |
630 | if ((next = try_combine (insn, XEXP (links, 0), | |
631 | XEXP (nextlinks, 0))) != 0) | |
632 | goto retry; | |
633 | ||
634 | if (GET_CODE (insn) != NOTE) | |
635 | record_dead_and_set_regs (insn); | |
636 | ||
637 | retry: | |
638 | ; | |
639 | } | |
640 | } | |
641 | ||
642 | total_attempts += combine_attempts; | |
643 | total_merges += combine_merges; | |
644 | total_extras += combine_extras; | |
645 | total_successes += combine_successes; | |
1a26b032 | 646 | |
951553af | 647 | nonzero_sign_valid = 0; |
230d793d | 648 | } |
ef026f91 RS |
649 | |
650 | /* Wipe the reg_last_xxx arrays in preparation for another pass. */ | |
651 | ||
652 | static void | |
653 | init_reg_last_arrays () | |
654 | { | |
655 | int nregs = combine_max_regno; | |
656 | ||
4c9a05bc RK |
657 | bzero ((char *) reg_last_death, nregs * sizeof (rtx)); |
658 | bzero ((char *) reg_last_set, nregs * sizeof (rtx)); | |
659 | bzero ((char *) reg_last_set_value, nregs * sizeof (rtx)); | |
660 | bzero ((char *) reg_last_set_table_tick, nregs * sizeof (int)); | |
661 | bzero ((char *) reg_last_set_label, nregs * sizeof (int)); | |
ef026f91 | 662 | bzero (reg_last_set_invalid, nregs * sizeof (char)); |
4c9a05bc RK |
663 | bzero ((char *) reg_last_set_mode, nregs * sizeof (enum machine_mode)); |
664 | bzero ((char *) reg_last_set_nonzero_bits, nregs * sizeof (HOST_WIDE_INT)); | |
ef026f91 RS |
665 | bzero (reg_last_set_sign_bit_copies, nregs * sizeof (char)); |
666 | } | |
230d793d | 667 | \f |
7988fd36 RK |
668 | /* Set up any promoted values for incoming argument registers. */ |
669 | ||
ee791cc3 | 670 | static void |
7988fd36 RK |
671 | setup_incoming_promotions () |
672 | { | |
673 | #ifdef PROMOTE_FUNCTION_ARGS | |
674 | int regno; | |
675 | rtx reg; | |
676 | enum machine_mode mode; | |
677 | int unsignedp; | |
678 | rtx first = get_insns (); | |
679 | ||
680 | for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) | |
681 | if (FUNCTION_ARG_REGNO_P (regno) | |
682 | && (reg = promoted_input_arg (regno, &mode, &unsignedp)) != 0) | |
683 | record_value_for_reg (reg, first, | |
684 | gen_rtx (unsignedp ? ZERO_EXTEND : SIGN_EXTEND, | |
500c518b RK |
685 | GET_MODE (reg), |
686 | gen_rtx (CLOBBER, mode, const0_rtx))); | |
7988fd36 RK |
687 | #endif |
688 | } | |
689 | \f | |
230d793d | 690 | /* Called via note_stores. If X is a pseudo that is used in more than |
5f4f0e22 | 691 | one basic block, is narrower that HOST_BITS_PER_WIDE_INT, and is being |
951553af | 692 | set, record what bits are known zero. If we are clobbering X, |
230d793d RS |
693 | ignore this "set" because the clobbered value won't be used. |
694 | ||
695 | If we are setting only a portion of X and we can't figure out what | |
696 | portion, assume all bits will be used since we don't know what will | |
d0ab8cd3 RK |
697 | be happening. |
698 | ||
699 | Similarly, set how many bits of X are known to be copies of the sign bit | |
700 | at all locations in the function. This is the smallest number implied | |
701 | by any set of X. */ | |
230d793d RS |
702 | |
703 | static void | |
951553af | 704 | set_nonzero_bits_and_sign_copies (x, set) |
230d793d RS |
705 | rtx x; |
706 | rtx set; | |
707 | { | |
d0ab8cd3 RK |
708 | int num; |
709 | ||
230d793d RS |
710 | if (GET_CODE (x) == REG |
711 | && REGNO (x) >= FIRST_PSEUDO_REGISTER | |
712 | && reg_n_sets[REGNO (x)] > 1 | |
713 | && reg_basic_block[REGNO (x)] < 0 | |
e8095e80 RK |
714 | /* If this register is undefined at the start of the file, we can't |
715 | say what its contents were. */ | |
716 | && ! (basic_block_live_at_start[0][REGNO (x) / REGSET_ELT_BITS] | |
717 | & ((REGSET_ELT_TYPE) 1 << (REGNO (x) % REGSET_ELT_BITS))) | |
5f4f0e22 | 718 | && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT) |
230d793d RS |
719 | { |
720 | if (GET_CODE (set) == CLOBBER) | |
e8095e80 RK |
721 | { |
722 | reg_nonzero_bits[REGNO (x)] = GET_MODE_MASK (GET_MODE (x)); | |
723 | reg_sign_bit_copies[REGNO (x)] = 0; | |
724 | return; | |
725 | } | |
230d793d RS |
726 | |
727 | /* If this is a complex assignment, see if we can convert it into a | |
5089e22e | 728 | simple assignment. */ |
230d793d | 729 | set = expand_field_assignment (set); |
d79f08e0 RK |
730 | |
731 | /* If this is a simple assignment, or we have a paradoxical SUBREG, | |
732 | set what we know about X. */ | |
733 | ||
734 | if (SET_DEST (set) == x | |
735 | || (GET_CODE (SET_DEST (set)) == SUBREG | |
705c7b3b JW |
736 | && (GET_MODE_SIZE (GET_MODE (SET_DEST (set))) |
737 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (set))))) | |
d79f08e0 | 738 | && SUBREG_REG (SET_DEST (set)) == x)) |
d0ab8cd3 | 739 | { |
9afa3d54 RK |
740 | rtx src = SET_SRC (set); |
741 | ||
742 | #ifdef SHORT_IMMEDIATES_SIGN_EXTEND | |
743 | /* If X is narrower than a word and SRC is a non-negative | |
744 | constant that would appear negative in the mode of X, | |
745 | sign-extend it for use in reg_nonzero_bits because some | |
746 | machines (maybe most) will actually do the sign-extension | |
747 | and this is the conservative approach. | |
748 | ||
749 | ??? For 2.5, try to tighten up the MD files in this regard | |
750 | instead of this kludge. */ | |
751 | ||
752 | if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD | |
753 | && GET_CODE (src) == CONST_INT | |
754 | && INTVAL (src) > 0 | |
755 | && 0 != (INTVAL (src) | |
756 | & ((HOST_WIDE_INT) 1 | |
9e69be8c | 757 | << (GET_MODE_BITSIZE (GET_MODE (x)) - 1)))) |
9afa3d54 RK |
758 | src = GEN_INT (INTVAL (src) |
759 | | ((HOST_WIDE_INT) (-1) | |
760 | << GET_MODE_BITSIZE (GET_MODE (x)))); | |
761 | #endif | |
762 | ||
951553af | 763 | reg_nonzero_bits[REGNO (x)] |
9afa3d54 | 764 | |= nonzero_bits (src, nonzero_bits_mode); |
d0ab8cd3 RK |
765 | num = num_sign_bit_copies (SET_SRC (set), GET_MODE (x)); |
766 | if (reg_sign_bit_copies[REGNO (x)] == 0 | |
767 | || reg_sign_bit_copies[REGNO (x)] > num) | |
768 | reg_sign_bit_copies[REGNO (x)] = num; | |
769 | } | |
230d793d | 770 | else |
d0ab8cd3 | 771 | { |
951553af | 772 | reg_nonzero_bits[REGNO (x)] = GET_MODE_MASK (GET_MODE (x)); |
d0ab8cd3 RK |
773 | reg_sign_bit_copies[REGNO (x)] = 0; |
774 | } | |
230d793d RS |
775 | } |
776 | } | |
777 | \f | |
778 | /* See if INSN can be combined into I3. PRED and SUCC are optionally | |
779 | insns that were previously combined into I3 or that will be combined | |
780 | into the merger of INSN and I3. | |
781 | ||
782 | Return 0 if the combination is not allowed for any reason. | |
783 | ||
784 | If the combination is allowed, *PDEST will be set to the single | |
785 | destination of INSN and *PSRC to the single source, and this function | |
786 | will return 1. */ | |
787 | ||
788 | static int | |
789 | can_combine_p (insn, i3, pred, succ, pdest, psrc) | |
790 | rtx insn; | |
791 | rtx i3; | |
792 | rtx pred, succ; | |
793 | rtx *pdest, *psrc; | |
794 | { | |
795 | int i; | |
796 | rtx set = 0, src, dest; | |
797 | rtx p, link; | |
798 | int all_adjacent = (succ ? (next_active_insn (insn) == succ | |
799 | && next_active_insn (succ) == i3) | |
800 | : next_active_insn (insn) == i3); | |
801 | ||
802 | /* Can combine only if previous insn is a SET of a REG, a SUBREG or CC0. | |
803 | or a PARALLEL consisting of such a SET and CLOBBERs. | |
804 | ||
805 | If INSN has CLOBBER parallel parts, ignore them for our processing. | |
806 | By definition, these happen during the execution of the insn. When it | |
807 | is merged with another insn, all bets are off. If they are, in fact, | |
808 | needed and aren't also supplied in I3, they may be added by | |
809 | recog_for_combine. Otherwise, it won't match. | |
810 | ||
811 | We can also ignore a SET whose SET_DEST is mentioned in a REG_UNUSED | |
812 | note. | |
813 | ||
814 | Get the source and destination of INSN. If more than one, can't | |
815 | combine. */ | |
816 | ||
817 | if (GET_CODE (PATTERN (insn)) == SET) | |
818 | set = PATTERN (insn); | |
819 | else if (GET_CODE (PATTERN (insn)) == PARALLEL | |
820 | && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET) | |
821 | { | |
822 | for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) | |
823 | { | |
824 | rtx elt = XVECEXP (PATTERN (insn), 0, i); | |
825 | ||
826 | switch (GET_CODE (elt)) | |
827 | { | |
828 | /* We can ignore CLOBBERs. */ | |
829 | case CLOBBER: | |
830 | break; | |
831 | ||
832 | case SET: | |
833 | /* Ignore SETs whose result isn't used but not those that | |
834 | have side-effects. */ | |
835 | if (find_reg_note (insn, REG_UNUSED, SET_DEST (elt)) | |
836 | && ! side_effects_p (elt)) | |
837 | break; | |
838 | ||
839 | /* If we have already found a SET, this is a second one and | |
840 | so we cannot combine with this insn. */ | |
841 | if (set) | |
842 | return 0; | |
843 | ||
844 | set = elt; | |
845 | break; | |
846 | ||
847 | default: | |
848 | /* Anything else means we can't combine. */ | |
849 | return 0; | |
850 | } | |
851 | } | |
852 | ||
853 | if (set == 0 | |
854 | /* If SET_SRC is an ASM_OPERANDS we can't throw away these CLOBBERs, | |
855 | so don't do anything with it. */ | |
856 | || GET_CODE (SET_SRC (set)) == ASM_OPERANDS) | |
857 | return 0; | |
858 | } | |
859 | else | |
860 | return 0; | |
861 | ||
862 | if (set == 0) | |
863 | return 0; | |
864 | ||
865 | set = expand_field_assignment (set); | |
866 | src = SET_SRC (set), dest = SET_DEST (set); | |
867 | ||
868 | /* Don't eliminate a store in the stack pointer. */ | |
869 | if (dest == stack_pointer_rtx | |
230d793d RS |
870 | /* If we couldn't eliminate a field assignment, we can't combine. */ |
871 | || GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == STRICT_LOW_PART | |
872 | /* Don't combine with an insn that sets a register to itself if it has | |
873 | a REG_EQUAL note. This may be part of a REG_NO_CONFLICT sequence. */ | |
5f4f0e22 | 874 | || (rtx_equal_p (src, dest) && find_reg_note (insn, REG_EQUAL, NULL_RTX)) |
230d793d RS |
875 | /* Can't merge a function call. */ |
876 | || GET_CODE (src) == CALL | |
cd5e8f1f RK |
877 | /* Don't eliminate a function call argument. */ |
878 | || (GET_CODE (i3) == CALL_INSN && find_reg_fusage (i3, USE, dest)) | |
230d793d RS |
879 | /* Don't substitute into an incremented register. */ |
880 | || FIND_REG_INC_NOTE (i3, dest) | |
881 | || (succ && FIND_REG_INC_NOTE (succ, dest)) | |
882 | /* Don't combine the end of a libcall into anything. */ | |
5f4f0e22 | 883 | || find_reg_note (insn, REG_RETVAL, NULL_RTX) |
230d793d RS |
884 | /* Make sure that DEST is not used after SUCC but before I3. */ |
885 | || (succ && ! all_adjacent | |
886 | && reg_used_between_p (dest, succ, i3)) | |
887 | /* Make sure that the value that is to be substituted for the register | |
888 | does not use any registers whose values alter in between. However, | |
889 | If the insns are adjacent, a use can't cross a set even though we | |
890 | think it might (this can happen for a sequence of insns each setting | |
891 | the same destination; reg_last_set of that register might point to | |
d81481d3 RK |
892 | a NOTE). If INSN has a REG_EQUIV note, the register is always |
893 | equivalent to the memory so the substitution is valid even if there | |
894 | are intervening stores. Also, don't move a volatile asm or | |
895 | UNSPEC_VOLATILE across any other insns. */ | |
230d793d | 896 | || (! all_adjacent |
d81481d3 RK |
897 | && (((GET_CODE (src) != MEM |
898 | || ! find_reg_note (insn, REG_EQUIV, src)) | |
899 | && use_crosses_set_p (src, INSN_CUID (insn))) | |
a66a10c7 RS |
900 | || (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src)) |
901 | || GET_CODE (src) == UNSPEC_VOLATILE)) | |
230d793d RS |
902 | /* If there is a REG_NO_CONFLICT note for DEST in I3 or SUCC, we get |
903 | better register allocation by not doing the combine. */ | |
904 | || find_reg_note (i3, REG_NO_CONFLICT, dest) | |
905 | || (succ && find_reg_note (succ, REG_NO_CONFLICT, dest)) | |
906 | /* Don't combine across a CALL_INSN, because that would possibly | |
907 | change whether the life span of some REGs crosses calls or not, | |
908 | and it is a pain to update that information. | |
909 | Exception: if source is a constant, moving it later can't hurt. | |
910 | Accept that special case, because it helps -fforce-addr a lot. */ | |
911 | || (INSN_CUID (insn) < last_call_cuid && ! CONSTANT_P (src))) | |
912 | return 0; | |
913 | ||
914 | /* DEST must either be a REG or CC0. */ | |
915 | if (GET_CODE (dest) == REG) | |
916 | { | |
917 | /* If register alignment is being enforced for multi-word items in all | |
918 | cases except for parameters, it is possible to have a register copy | |
919 | insn referencing a hard register that is not allowed to contain the | |
920 | mode being copied and which would not be valid as an operand of most | |
921 | insns. Eliminate this problem by not combining with such an insn. | |
922 | ||
923 | Also, on some machines we don't want to extend the life of a hard | |
924 | register. */ | |
925 | ||
926 | if (GET_CODE (src) == REG | |
927 | && ((REGNO (dest) < FIRST_PSEUDO_REGISTER | |
928 | && ! HARD_REGNO_MODE_OK (REGNO (dest), GET_MODE (dest))) | |
c448a43e RK |
929 | /* Don't extend the life of a hard register unless it is |
930 | user variable (if we have few registers) or it can't | |
931 | fit into the desired register (meaning something special | |
932 | is going on). */ | |
230d793d | 933 | || (REGNO (src) < FIRST_PSEUDO_REGISTER |
c448a43e RK |
934 | && (! HARD_REGNO_MODE_OK (REGNO (src), GET_MODE (src)) |
935 | #ifdef SMALL_REGISTER_CLASSES | |
936 | || ! REG_USERVAR_P (src) | |
230d793d | 937 | #endif |
c448a43e | 938 | )))) |
230d793d RS |
939 | return 0; |
940 | } | |
941 | else if (GET_CODE (dest) != CC0) | |
942 | return 0; | |
943 | ||
5f96750d RS |
944 | /* Don't substitute for a register intended as a clobberable operand. |
945 | Similarly, don't substitute an expression containing a register that | |
946 | will be clobbered in I3. */ | |
230d793d RS |
947 | if (GET_CODE (PATTERN (i3)) == PARALLEL) |
948 | for (i = XVECLEN (PATTERN (i3), 0) - 1; i >= 0; i--) | |
949 | if (GET_CODE (XVECEXP (PATTERN (i3), 0, i)) == CLOBBER | |
5f96750d RS |
950 | && (reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (i3), 0, i), 0), |
951 | src) | |
952 | || rtx_equal_p (XEXP (XVECEXP (PATTERN (i3), 0, i), 0), dest))) | |
230d793d RS |
953 | return 0; |
954 | ||
955 | /* If INSN contains anything volatile, or is an `asm' (whether volatile | |
956 | or not), reject, unless nothing volatile comes between it and I3, | |
957 | with the exception of SUCC. */ | |
958 | ||
959 | if (GET_CODE (src) == ASM_OPERANDS || volatile_refs_p (src)) | |
960 | for (p = NEXT_INSN (insn); p != i3; p = NEXT_INSN (p)) | |
961 | if (GET_RTX_CLASS (GET_CODE (p)) == 'i' | |
962 | && p != succ && volatile_refs_p (PATTERN (p))) | |
963 | return 0; | |
964 | ||
4b2cb4a2 RS |
965 | /* If there are any volatile insns between INSN and I3, reject, because |
966 | they might affect machine state. */ | |
967 | ||
968 | for (p = NEXT_INSN (insn); p != i3; p = NEXT_INSN (p)) | |
969 | if (GET_RTX_CLASS (GET_CODE (p)) == 'i' | |
970 | && p != succ && volatile_insn_p (PATTERN (p))) | |
971 | return 0; | |
972 | ||
230d793d RS |
973 | /* If INSN or I2 contains an autoincrement or autodecrement, |
974 | make sure that register is not used between there and I3, | |
975 | and not already used in I3 either. | |
976 | Also insist that I3 not be a jump; if it were one | |
977 | and the incremented register were spilled, we would lose. */ | |
978 | ||
979 | #ifdef AUTO_INC_DEC | |
980 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
981 | if (REG_NOTE_KIND (link) == REG_INC | |
982 | && (GET_CODE (i3) == JUMP_INSN | |
983 | || reg_used_between_p (XEXP (link, 0), insn, i3) | |
984 | || reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i3)))) | |
985 | return 0; | |
986 | #endif | |
987 | ||
988 | #ifdef HAVE_cc0 | |
989 | /* Don't combine an insn that follows a CC0-setting insn. | |
990 | An insn that uses CC0 must not be separated from the one that sets it. | |
991 | We do, however, allow I2 to follow a CC0-setting insn if that insn | |
992 | is passed as I1; in that case it will be deleted also. | |
993 | We also allow combining in this case if all the insns are adjacent | |
994 | because that would leave the two CC0 insns adjacent as well. | |
995 | It would be more logical to test whether CC0 occurs inside I1 or I2, | |
996 | but that would be much slower, and this ought to be equivalent. */ | |
997 | ||
998 | p = prev_nonnote_insn (insn); | |
999 | if (p && p != pred && GET_CODE (p) == INSN && sets_cc0_p (PATTERN (p)) | |
1000 | && ! all_adjacent) | |
1001 | return 0; | |
1002 | #endif | |
1003 | ||
1004 | /* If we get here, we have passed all the tests and the combination is | |
1005 | to be allowed. */ | |
1006 | ||
1007 | *pdest = dest; | |
1008 | *psrc = src; | |
1009 | ||
1010 | return 1; | |
1011 | } | |
1012 | \f | |
1013 | /* LOC is the location within I3 that contains its pattern or the component | |
1014 | of a PARALLEL of the pattern. We validate that it is valid for combining. | |
1015 | ||
1016 | One problem is if I3 modifies its output, as opposed to replacing it | |
1017 | entirely, we can't allow the output to contain I2DEST or I1DEST as doing | |
1018 | so would produce an insn that is not equivalent to the original insns. | |
1019 | ||
1020 | Consider: | |
1021 | ||
1022 | (set (reg:DI 101) (reg:DI 100)) | |
1023 | (set (subreg:SI (reg:DI 101) 0) <foo>) | |
1024 | ||
1025 | This is NOT equivalent to: | |
1026 | ||
1027 | (parallel [(set (subreg:SI (reg:DI 100) 0) <foo>) | |
1028 | (set (reg:DI 101) (reg:DI 100))]) | |
1029 | ||
1030 | Not only does this modify 100 (in which case it might still be valid | |
1031 | if 100 were dead in I2), it sets 101 to the ORIGINAL value of 100. | |
1032 | ||
1033 | We can also run into a problem if I2 sets a register that I1 | |
1034 | uses and I1 gets directly substituted into I3 (not via I2). In that | |
1035 | case, we would be getting the wrong value of I2DEST into I3, so we | |
1036 | must reject the combination. This case occurs when I2 and I1 both | |
1037 | feed into I3, rather than when I1 feeds into I2, which feeds into I3. | |
1038 | If I1_NOT_IN_SRC is non-zero, it means that finding I1 in the source | |
1039 | of a SET must prevent combination from occurring. | |
1040 | ||
1041 | On machines where SMALL_REGISTER_CLASSES is defined, we don't combine | |
c448a43e RK |
1042 | if the destination of a SET is a hard register that isn't a user |
1043 | variable. | |
230d793d RS |
1044 | |
1045 | Before doing the above check, we first try to expand a field assignment | |
1046 | into a set of logical operations. | |
1047 | ||
1048 | If PI3_DEST_KILLED is non-zero, it is a pointer to a location in which | |
1049 | we place a register that is both set and used within I3. If more than one | |
1050 | such register is detected, we fail. | |
1051 | ||
1052 | Return 1 if the combination is valid, zero otherwise. */ | |
1053 | ||
1054 | static int | |
1055 | combinable_i3pat (i3, loc, i2dest, i1dest, i1_not_in_src, pi3dest_killed) | |
1056 | rtx i3; | |
1057 | rtx *loc; | |
1058 | rtx i2dest; | |
1059 | rtx i1dest; | |
1060 | int i1_not_in_src; | |
1061 | rtx *pi3dest_killed; | |
1062 | { | |
1063 | rtx x = *loc; | |
1064 | ||
1065 | if (GET_CODE (x) == SET) | |
1066 | { | |
1067 | rtx set = expand_field_assignment (x); | |
1068 | rtx dest = SET_DEST (set); | |
1069 | rtx src = SET_SRC (set); | |
1070 | rtx inner_dest = dest, inner_src = src; | |
1071 | ||
1072 | SUBST (*loc, set); | |
1073 | ||
1074 | while (GET_CODE (inner_dest) == STRICT_LOW_PART | |
1075 | || GET_CODE (inner_dest) == SUBREG | |
1076 | || GET_CODE (inner_dest) == ZERO_EXTRACT) | |
1077 | inner_dest = XEXP (inner_dest, 0); | |
1078 | ||
1079 | /* We probably don't need this any more now that LIMIT_RELOAD_CLASS | |
1080 | was added. */ | |
1081 | #if 0 | |
1082 | while (GET_CODE (inner_src) == STRICT_LOW_PART | |
1083 | || GET_CODE (inner_src) == SUBREG | |
1084 | || GET_CODE (inner_src) == ZERO_EXTRACT) | |
1085 | inner_src = XEXP (inner_src, 0); | |
1086 | ||
1087 | /* If it is better that two different modes keep two different pseudos, | |
1088 | avoid combining them. This avoids producing the following pattern | |
1089 | on a 386: | |
1090 | (set (subreg:SI (reg/v:QI 21) 0) | |
1091 | (lshiftrt:SI (reg/v:SI 20) | |
1092 | (const_int 24))) | |
1093 | If that were made, reload could not handle the pair of | |
1094 | reg 20/21, since it would try to get any GENERAL_REGS | |
1095 | but some of them don't handle QImode. */ | |
1096 | ||
1097 | if (rtx_equal_p (inner_src, i2dest) | |
1098 | && GET_CODE (inner_dest) == REG | |
1099 | && ! MODES_TIEABLE_P (GET_MODE (i2dest), GET_MODE (inner_dest))) | |
1100 | return 0; | |
1101 | #endif | |
1102 | ||
1103 | /* Check for the case where I3 modifies its output, as | |
1104 | discussed above. */ | |
1105 | if ((inner_dest != dest | |
1106 | && (reg_overlap_mentioned_p (i2dest, inner_dest) | |
1107 | || (i1dest && reg_overlap_mentioned_p (i1dest, inner_dest)))) | |
3f508eca RK |
1108 | /* This is the same test done in can_combine_p except that we |
1109 | allow a hard register with SMALL_REGISTER_CLASSES if SRC is a | |
1110 | CALL operation. */ | |
230d793d | 1111 | || (GET_CODE (inner_dest) == REG |
dfbe1b2f | 1112 | && REGNO (inner_dest) < FIRST_PSEUDO_REGISTER |
c448a43e RK |
1113 | && (! HARD_REGNO_MODE_OK (REGNO (inner_dest), |
1114 | GET_MODE (inner_dest)) | |
3f508eca | 1115 | #ifdef SMALL_REGISTER_CLASSES |
c448a43e | 1116 | || (GET_CODE (src) != CALL && ! REG_USERVAR_P (inner_dest)) |
230d793d | 1117 | #endif |
c448a43e | 1118 | )) |
230d793d RS |
1119 | || (i1_not_in_src && reg_overlap_mentioned_p (i1dest, src))) |
1120 | return 0; | |
1121 | ||
1122 | /* If DEST is used in I3, it is being killed in this insn, | |
36a9c2e9 JL |
1123 | so record that for later. |
1124 | Never add REG_DEAD notes for the FRAME_POINTER_REGNUM or the | |
1125 | STACK_POINTER_REGNUM, since these are always considered to be | |
1126 | live. Similarly for ARG_POINTER_REGNUM if it is fixed. */ | |
230d793d | 1127 | if (pi3dest_killed && GET_CODE (dest) == REG |
36a9c2e9 JL |
1128 | && reg_referenced_p (dest, PATTERN (i3)) |
1129 | && REGNO (dest) != FRAME_POINTER_REGNUM | |
6d7096b0 DE |
1130 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
1131 | && REGNO (dest) != HARD_FRAME_POINTER_REGNUM | |
1132 | #endif | |
36a9c2e9 JL |
1133 | #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM |
1134 | && (REGNO (dest) != ARG_POINTER_REGNUM | |
1135 | || ! fixed_regs [REGNO (dest)]) | |
1136 | #endif | |
1137 | && REGNO (dest) != STACK_POINTER_REGNUM) | |
230d793d RS |
1138 | { |
1139 | if (*pi3dest_killed) | |
1140 | return 0; | |
1141 | ||
1142 | *pi3dest_killed = dest; | |
1143 | } | |
1144 | } | |
1145 | ||
1146 | else if (GET_CODE (x) == PARALLEL) | |
1147 | { | |
1148 | int i; | |
1149 | ||
1150 | for (i = 0; i < XVECLEN (x, 0); i++) | |
1151 | if (! combinable_i3pat (i3, &XVECEXP (x, 0, i), i2dest, i1dest, | |
1152 | i1_not_in_src, pi3dest_killed)) | |
1153 | return 0; | |
1154 | } | |
1155 | ||
1156 | return 1; | |
1157 | } | |
1158 | \f | |
1159 | /* Try to combine the insns I1 and I2 into I3. | |
1160 | Here I1 and I2 appear earlier than I3. | |
1161 | I1 can be zero; then we combine just I2 into I3. | |
1162 | ||
1163 | It we are combining three insns and the resulting insn is not recognized, | |
1164 | try splitting it into two insns. If that happens, I2 and I3 are retained | |
1165 | and I1 is pseudo-deleted by turning it into a NOTE. Otherwise, I1 and I2 | |
1166 | are pseudo-deleted. | |
1167 | ||
abe6e52f RK |
1168 | Return 0 if the combination does not work. Then nothing is changed. |
1169 | If we did the combination, return the insn at which combine should | |
1170 | resume scanning. */ | |
230d793d RS |
1171 | |
1172 | static rtx | |
1173 | try_combine (i3, i2, i1) | |
1174 | register rtx i3, i2, i1; | |
1175 | { | |
1176 | /* New patterns for I3 and I3, respectively. */ | |
1177 | rtx newpat, newi2pat = 0; | |
1178 | /* Indicates need to preserve SET in I1 or I2 in I3 if it is not dead. */ | |
1179 | int added_sets_1, added_sets_2; | |
1180 | /* Total number of SETs to put into I3. */ | |
1181 | int total_sets; | |
1182 | /* Nonzero is I2's body now appears in I3. */ | |
1183 | int i2_is_used; | |
1184 | /* INSN_CODEs for new I3, new I2, and user of condition code. */ | |
1185 | int insn_code_number, i2_code_number, other_code_number; | |
1186 | /* Contains I3 if the destination of I3 is used in its source, which means | |
1187 | that the old life of I3 is being killed. If that usage is placed into | |
1188 | I2 and not in I3, a REG_DEAD note must be made. */ | |
1189 | rtx i3dest_killed = 0; | |
1190 | /* SET_DEST and SET_SRC of I2 and I1. */ | |
1191 | rtx i2dest, i2src, i1dest = 0, i1src = 0; | |
1192 | /* PATTERN (I2), or a copy of it in certain cases. */ | |
1193 | rtx i2pat; | |
1194 | /* Indicates if I2DEST or I1DEST is in I2SRC or I1_SRC. */ | |
c4e861e8 | 1195 | int i2dest_in_i2src = 0, i1dest_in_i1src = 0, i2dest_in_i1src = 0; |
230d793d RS |
1196 | int i1_feeds_i3 = 0; |
1197 | /* Notes that must be added to REG_NOTES in I3 and I2. */ | |
1198 | rtx new_i3_notes, new_i2_notes; | |
176c9e6b JW |
1199 | /* Notes that we substituted I3 into I2 instead of the normal case. */ |
1200 | int i3_subst_into_i2 = 0; | |
df7d75de RK |
1201 | /* Notes that I1, I2 or I3 is a MULT operation. */ |
1202 | int have_mult = 0; | |
230d793d RS |
1203 | |
1204 | int maxreg; | |
1205 | rtx temp; | |
1206 | register rtx link; | |
1207 | int i; | |
1208 | ||
1209 | /* If any of I1, I2, and I3 isn't really an insn, we can't do anything. | |
1210 | This can occur when flow deletes an insn that it has merged into an | |
1211 | auto-increment address. We also can't do anything if I3 has a | |
1212 | REG_LIBCALL note since we don't want to disrupt the contiguity of a | |
1213 | libcall. */ | |
1214 | ||
1215 | if (GET_RTX_CLASS (GET_CODE (i3)) != 'i' | |
1216 | || GET_RTX_CLASS (GET_CODE (i2)) != 'i' | |
1217 | || (i1 && GET_RTX_CLASS (GET_CODE (i1)) != 'i') | |
5f4f0e22 | 1218 | || find_reg_note (i3, REG_LIBCALL, NULL_RTX)) |
230d793d RS |
1219 | return 0; |
1220 | ||
1221 | combine_attempts++; | |
1222 | ||
1223 | undobuf.num_undo = previous_num_undos = 0; | |
1224 | undobuf.other_insn = 0; | |
1225 | ||
1226 | /* Save the current high-water-mark so we can free storage if we didn't | |
1227 | accept this combination. */ | |
1228 | undobuf.storage = (char *) oballoc (0); | |
1229 | ||
6e25d159 RK |
1230 | /* Reset the hard register usage information. */ |
1231 | CLEAR_HARD_REG_SET (newpat_used_regs); | |
1232 | ||
230d793d RS |
1233 | /* If I1 and I2 both feed I3, they can be in any order. To simplify the |
1234 | code below, set I1 to be the earlier of the two insns. */ | |
1235 | if (i1 && INSN_CUID (i1) > INSN_CUID (i2)) | |
1236 | temp = i1, i1 = i2, i2 = temp; | |
1237 | ||
abe6e52f | 1238 | added_links_insn = 0; |
137e889e | 1239 | |
230d793d RS |
1240 | /* First check for one important special-case that the code below will |
1241 | not handle. Namely, the case where I1 is zero, I2 has multiple sets, | |
1242 | and I3 is a SET whose SET_SRC is a SET_DEST in I2. In that case, | |
1243 | we may be able to replace that destination with the destination of I3. | |
1244 | This occurs in the common code where we compute both a quotient and | |
1245 | remainder into a structure, in which case we want to do the computation | |
1246 | directly into the structure to avoid register-register copies. | |
1247 | ||
1248 | We make very conservative checks below and only try to handle the | |
1249 | most common cases of this. For example, we only handle the case | |
1250 | where I2 and I3 are adjacent to avoid making difficult register | |
1251 | usage tests. */ | |
1252 | ||
1253 | if (i1 == 0 && GET_CODE (i3) == INSN && GET_CODE (PATTERN (i3)) == SET | |
1254 | && GET_CODE (SET_SRC (PATTERN (i3))) == REG | |
1255 | && REGNO (SET_SRC (PATTERN (i3))) >= FIRST_PSEUDO_REGISTER | |
1256 | #ifdef SMALL_REGISTER_CLASSES | |
1257 | && (GET_CODE (SET_DEST (PATTERN (i3))) != REG | |
c448a43e RK |
1258 | || REGNO (SET_DEST (PATTERN (i3))) >= FIRST_PSEUDO_REGISTER |
1259 | || REG_USERVAR_P (SET_DEST (PATTERN (i3)))) | |
230d793d RS |
1260 | #endif |
1261 | && find_reg_note (i3, REG_DEAD, SET_SRC (PATTERN (i3))) | |
1262 | && GET_CODE (PATTERN (i2)) == PARALLEL | |
1263 | && ! side_effects_p (SET_DEST (PATTERN (i3))) | |
5089e22e RS |
1264 | /* If the dest of I3 is a ZERO_EXTRACT or STRICT_LOW_PART, the code |
1265 | below would need to check what is inside (and reg_overlap_mentioned_p | |
1266 | doesn't support those codes anyway). Don't allow those destinations; | |
1267 | the resulting insn isn't likely to be recognized anyway. */ | |
1268 | && GET_CODE (SET_DEST (PATTERN (i3))) != ZERO_EXTRACT | |
1269 | && GET_CODE (SET_DEST (PATTERN (i3))) != STRICT_LOW_PART | |
230d793d RS |
1270 | && ! reg_overlap_mentioned_p (SET_SRC (PATTERN (i3)), |
1271 | SET_DEST (PATTERN (i3))) | |
1272 | && next_real_insn (i2) == i3) | |
5089e22e RS |
1273 | { |
1274 | rtx p2 = PATTERN (i2); | |
1275 | ||
1276 | /* Make sure that the destination of I3, | |
1277 | which we are going to substitute into one output of I2, | |
1278 | is not used within another output of I2. We must avoid making this: | |
1279 | (parallel [(set (mem (reg 69)) ...) | |
1280 | (set (reg 69) ...)]) | |
1281 | which is not well-defined as to order of actions. | |
1282 | (Besides, reload can't handle output reloads for this.) | |
1283 | ||
1284 | The problem can also happen if the dest of I3 is a memory ref, | |
1285 | if another dest in I2 is an indirect memory ref. */ | |
1286 | for (i = 0; i < XVECLEN (p2, 0); i++) | |
1287 | if (GET_CODE (XVECEXP (p2, 0, i)) == SET | |
1288 | && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3)), | |
1289 | SET_DEST (XVECEXP (p2, 0, i)))) | |
1290 | break; | |
230d793d | 1291 | |
5089e22e RS |
1292 | if (i == XVECLEN (p2, 0)) |
1293 | for (i = 0; i < XVECLEN (p2, 0); i++) | |
1294 | if (SET_DEST (XVECEXP (p2, 0, i)) == SET_SRC (PATTERN (i3))) | |
1295 | { | |
1296 | combine_merges++; | |
230d793d | 1297 | |
5089e22e RS |
1298 | subst_insn = i3; |
1299 | subst_low_cuid = INSN_CUID (i2); | |
230d793d | 1300 | |
c4e861e8 | 1301 | added_sets_2 = added_sets_1 = 0; |
5089e22e | 1302 | i2dest = SET_SRC (PATTERN (i3)); |
230d793d | 1303 | |
5089e22e RS |
1304 | /* Replace the dest in I2 with our dest and make the resulting |
1305 | insn the new pattern for I3. Then skip to where we | |
1306 | validate the pattern. Everything was set up above. */ | |
1307 | SUBST (SET_DEST (XVECEXP (p2, 0, i)), | |
1308 | SET_DEST (PATTERN (i3))); | |
1309 | ||
1310 | newpat = p2; | |
176c9e6b | 1311 | i3_subst_into_i2 = 1; |
5089e22e RS |
1312 | goto validate_replacement; |
1313 | } | |
1314 | } | |
230d793d RS |
1315 | |
1316 | #ifndef HAVE_cc0 | |
1317 | /* If we have no I1 and I2 looks like: | |
1318 | (parallel [(set (reg:CC X) (compare:CC OP (const_int 0))) | |
1319 | (set Y OP)]) | |
1320 | make up a dummy I1 that is | |
1321 | (set Y OP) | |
1322 | and change I2 to be | |
1323 | (set (reg:CC X) (compare:CC Y (const_int 0))) | |
1324 | ||
1325 | (We can ignore any trailing CLOBBERs.) | |
1326 | ||
1327 | This undoes a previous combination and allows us to match a branch-and- | |
1328 | decrement insn. */ | |
1329 | ||
1330 | if (i1 == 0 && GET_CODE (PATTERN (i2)) == PARALLEL | |
1331 | && XVECLEN (PATTERN (i2), 0) >= 2 | |
1332 | && GET_CODE (XVECEXP (PATTERN (i2), 0, 0)) == SET | |
1333 | && (GET_MODE_CLASS (GET_MODE (SET_DEST (XVECEXP (PATTERN (i2), 0, 0)))) | |
1334 | == MODE_CC) | |
1335 | && GET_CODE (SET_SRC (XVECEXP (PATTERN (i2), 0, 0))) == COMPARE | |
1336 | && XEXP (SET_SRC (XVECEXP (PATTERN (i2), 0, 0)), 1) == const0_rtx | |
1337 | && GET_CODE (XVECEXP (PATTERN (i2), 0, 1)) == SET | |
1338 | && GET_CODE (SET_DEST (XVECEXP (PATTERN (i2), 0, 1))) == REG | |
1339 | && rtx_equal_p (XEXP (SET_SRC (XVECEXP (PATTERN (i2), 0, 0)), 0), | |
1340 | SET_SRC (XVECEXP (PATTERN (i2), 0, 1)))) | |
1341 | { | |
1342 | for (i = XVECLEN (PATTERN (i2), 0) - 1; i >= 2; i--) | |
1343 | if (GET_CODE (XVECEXP (PATTERN (i2), 0, i)) != CLOBBER) | |
1344 | break; | |
1345 | ||
1346 | if (i == 1) | |
1347 | { | |
1348 | /* We make I1 with the same INSN_UID as I2. This gives it | |
1349 | the same INSN_CUID for value tracking. Our fake I1 will | |
1350 | never appear in the insn stream so giving it the same INSN_UID | |
1351 | as I2 will not cause a problem. */ | |
1352 | ||
3adde2a5 RK |
1353 | i1 = gen_rtx (INSN, VOIDmode, INSN_UID (i2), 0, i2, |
1354 | XVECEXP (PATTERN (i2), 0, 1), -1, 0, 0); | |
230d793d RS |
1355 | |
1356 | SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 0)); | |
1357 | SUBST (XEXP (SET_SRC (PATTERN (i2)), 0), | |
1358 | SET_DEST (PATTERN (i1))); | |
1359 | } | |
1360 | } | |
1361 | #endif | |
1362 | ||
1363 | /* Verify that I2 and I1 are valid for combining. */ | |
5f4f0e22 CH |
1364 | if (! can_combine_p (i2, i3, i1, NULL_RTX, &i2dest, &i2src) |
1365 | || (i1 && ! can_combine_p (i1, i3, NULL_RTX, i2, &i1dest, &i1src))) | |
230d793d RS |
1366 | { |
1367 | undo_all (); | |
1368 | return 0; | |
1369 | } | |
1370 | ||
1371 | /* Record whether I2DEST is used in I2SRC and similarly for the other | |
1372 | cases. Knowing this will help in register status updating below. */ | |
1373 | i2dest_in_i2src = reg_overlap_mentioned_p (i2dest, i2src); | |
1374 | i1dest_in_i1src = i1 && reg_overlap_mentioned_p (i1dest, i1src); | |
1375 | i2dest_in_i1src = i1 && reg_overlap_mentioned_p (i2dest, i1src); | |
1376 | ||
916f14f1 | 1377 | /* See if I1 directly feeds into I3. It does if I1DEST is not used |
230d793d RS |
1378 | in I2SRC. */ |
1379 | i1_feeds_i3 = i1 && ! reg_overlap_mentioned_p (i1dest, i2src); | |
1380 | ||
1381 | /* Ensure that I3's pattern can be the destination of combines. */ | |
1382 | if (! combinable_i3pat (i3, &PATTERN (i3), i2dest, i1dest, | |
1383 | i1 && i2dest_in_i1src && i1_feeds_i3, | |
1384 | &i3dest_killed)) | |
1385 | { | |
1386 | undo_all (); | |
1387 | return 0; | |
1388 | } | |
1389 | ||
df7d75de RK |
1390 | /* See if any of the insns is a MULT operation. Unless one is, we will |
1391 | reject a combination that is, since it must be slower. Be conservative | |
1392 | here. */ | |
1393 | if (GET_CODE (i2src) == MULT | |
1394 | || (i1 != 0 && GET_CODE (i1src) == MULT) | |
1395 | || (GET_CODE (PATTERN (i3)) == SET | |
1396 | && GET_CODE (SET_SRC (PATTERN (i3))) == MULT)) | |
1397 | have_mult = 1; | |
1398 | ||
230d793d RS |
1399 | /* If I3 has an inc, then give up if I1 or I2 uses the reg that is inc'd. |
1400 | We used to do this EXCEPT in one case: I3 has a post-inc in an | |
1401 | output operand. However, that exception can give rise to insns like | |
1402 | mov r3,(r3)+ | |
1403 | which is a famous insn on the PDP-11 where the value of r3 used as the | |
5089e22e | 1404 | source was model-dependent. Avoid this sort of thing. */ |
230d793d RS |
1405 | |
1406 | #if 0 | |
1407 | if (!(GET_CODE (PATTERN (i3)) == SET | |
1408 | && GET_CODE (SET_SRC (PATTERN (i3))) == REG | |
1409 | && GET_CODE (SET_DEST (PATTERN (i3))) == MEM | |
1410 | && (GET_CODE (XEXP (SET_DEST (PATTERN (i3)), 0)) == POST_INC | |
1411 | || GET_CODE (XEXP (SET_DEST (PATTERN (i3)), 0)) == POST_DEC))) | |
1412 | /* It's not the exception. */ | |
1413 | #endif | |
1414 | #ifdef AUTO_INC_DEC | |
1415 | for (link = REG_NOTES (i3); link; link = XEXP (link, 1)) | |
1416 | if (REG_NOTE_KIND (link) == REG_INC | |
1417 | && (reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i2)) | |
1418 | || (i1 != 0 | |
1419 | && reg_overlap_mentioned_p (XEXP (link, 0), PATTERN (i1))))) | |
1420 | { | |
1421 | undo_all (); | |
1422 | return 0; | |
1423 | } | |
1424 | #endif | |
1425 | ||
1426 | /* See if the SETs in I1 or I2 need to be kept around in the merged | |
1427 | instruction: whenever the value set there is still needed past I3. | |
1428 | For the SETs in I2, this is easy: we see if I2DEST dies or is set in I3. | |
1429 | ||
1430 | For the SET in I1, we have two cases: If I1 and I2 independently | |
1431 | feed into I3, the set in I1 needs to be kept around if I1DEST dies | |
1432 | or is set in I3. Otherwise (if I1 feeds I2 which feeds I3), the set | |
1433 | in I1 needs to be kept around unless I1DEST dies or is set in either | |
1434 | I2 or I3. We can distinguish these cases by seeing if I2SRC mentions | |
1435 | I1DEST. If so, we know I1 feeds into I2. */ | |
1436 | ||
1437 | added_sets_2 = ! dead_or_set_p (i3, i2dest); | |
1438 | ||
1439 | added_sets_1 | |
1440 | = i1 && ! (i1_feeds_i3 ? dead_or_set_p (i3, i1dest) | |
1441 | : (dead_or_set_p (i3, i1dest) || dead_or_set_p (i2, i1dest))); | |
1442 | ||
1443 | /* If the set in I2 needs to be kept around, we must make a copy of | |
1444 | PATTERN (I2), so that when we substitute I1SRC for I1DEST in | |
5089e22e | 1445 | PATTERN (I2), we are only substituting for the original I1DEST, not into |
230d793d RS |
1446 | an already-substituted copy. This also prevents making self-referential |
1447 | rtx. If I2 is a PARALLEL, we just need the piece that assigns I2SRC to | |
1448 | I2DEST. */ | |
1449 | ||
1450 | i2pat = (GET_CODE (PATTERN (i2)) == PARALLEL | |
1451 | ? gen_rtx (SET, VOIDmode, i2dest, i2src) | |
1452 | : PATTERN (i2)); | |
1453 | ||
1454 | if (added_sets_2) | |
1455 | i2pat = copy_rtx (i2pat); | |
1456 | ||
1457 | combine_merges++; | |
1458 | ||
1459 | /* Substitute in the latest insn for the regs set by the earlier ones. */ | |
1460 | ||
1461 | maxreg = max_reg_num (); | |
1462 | ||
1463 | subst_insn = i3; | |
230d793d RS |
1464 | |
1465 | /* It is possible that the source of I2 or I1 may be performing an | |
1466 | unneeded operation, such as a ZERO_EXTEND of something that is known | |
1467 | to have the high part zero. Handle that case by letting subst look at | |
1468 | the innermost one of them. | |
1469 | ||
1470 | Another way to do this would be to have a function that tries to | |
1471 | simplify a single insn instead of merging two or more insns. We don't | |
1472 | do this because of the potential of infinite loops and because | |
1473 | of the potential extra memory required. However, doing it the way | |
1474 | we are is a bit of a kludge and doesn't catch all cases. | |
1475 | ||
1476 | But only do this if -fexpensive-optimizations since it slows things down | |
1477 | and doesn't usually win. */ | |
1478 | ||
1479 | if (flag_expensive_optimizations) | |
1480 | { | |
1481 | /* Pass pc_rtx so no substitutions are done, just simplifications. | |
1482 | The cases that we are interested in here do not involve the few | |
1483 | cases were is_replaced is checked. */ | |
1484 | if (i1) | |
d0ab8cd3 RK |
1485 | { |
1486 | subst_low_cuid = INSN_CUID (i1); | |
1487 | i1src = subst (i1src, pc_rtx, pc_rtx, 0, 0); | |
1488 | } | |
230d793d | 1489 | else |
d0ab8cd3 RK |
1490 | { |
1491 | subst_low_cuid = INSN_CUID (i2); | |
1492 | i2src = subst (i2src, pc_rtx, pc_rtx, 0, 0); | |
1493 | } | |
230d793d RS |
1494 | |
1495 | previous_num_undos = undobuf.num_undo; | |
1496 | } | |
1497 | ||
1498 | #ifndef HAVE_cc0 | |
1499 | /* Many machines that don't use CC0 have insns that can both perform an | |
1500 | arithmetic operation and set the condition code. These operations will | |
1501 | be represented as a PARALLEL with the first element of the vector | |
1502 | being a COMPARE of an arithmetic operation with the constant zero. | |
1503 | The second element of the vector will set some pseudo to the result | |
1504 | of the same arithmetic operation. If we simplify the COMPARE, we won't | |
1505 | match such a pattern and so will generate an extra insn. Here we test | |
1506 | for this case, where both the comparison and the operation result are | |
1507 | needed, and make the PARALLEL by just replacing I2DEST in I3SRC with | |
1508 | I2SRC. Later we will make the PARALLEL that contains I2. */ | |
1509 | ||
1510 | if (i1 == 0 && added_sets_2 && GET_CODE (PATTERN (i3)) == SET | |
1511 | && GET_CODE (SET_SRC (PATTERN (i3))) == COMPARE | |
1512 | && XEXP (SET_SRC (PATTERN (i3)), 1) == const0_rtx | |
1513 | && rtx_equal_p (XEXP (SET_SRC (PATTERN (i3)), 0), i2dest)) | |
1514 | { | |
1515 | rtx *cc_use; | |
1516 | enum machine_mode compare_mode; | |
1517 | ||
1518 | newpat = PATTERN (i3); | |
1519 | SUBST (XEXP (SET_SRC (newpat), 0), i2src); | |
1520 | ||
1521 | i2_is_used = 1; | |
1522 | ||
1523 | #ifdef EXTRA_CC_MODES | |
1524 | /* See if a COMPARE with the operand we substituted in should be done | |
1525 | with the mode that is currently being used. If not, do the same | |
1526 | processing we do in `subst' for a SET; namely, if the destination | |
1527 | is used only once, try to replace it with a register of the proper | |
1528 | mode and also replace the COMPARE. */ | |
1529 | if (undobuf.other_insn == 0 | |
1530 | && (cc_use = find_single_use (SET_DEST (newpat), i3, | |
1531 | &undobuf.other_insn)) | |
77fa0940 RK |
1532 | && ((compare_mode = SELECT_CC_MODE (GET_CODE (*cc_use), |
1533 | i2src, const0_rtx)) | |
230d793d RS |
1534 | != GET_MODE (SET_DEST (newpat)))) |
1535 | { | |
1536 | int regno = REGNO (SET_DEST (newpat)); | |
1537 | rtx new_dest = gen_rtx (REG, compare_mode, regno); | |
1538 | ||
1539 | if (regno < FIRST_PSEUDO_REGISTER | |
1540 | || (reg_n_sets[regno] == 1 && ! added_sets_2 | |
1541 | && ! REG_USERVAR_P (SET_DEST (newpat)))) | |
1542 | { | |
1543 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1544 | SUBST (regno_reg_rtx[regno], new_dest); | |
1545 | ||
1546 | SUBST (SET_DEST (newpat), new_dest); | |
1547 | SUBST (XEXP (*cc_use, 0), new_dest); | |
1548 | SUBST (SET_SRC (newpat), | |
1549 | gen_rtx_combine (COMPARE, compare_mode, | |
1550 | i2src, const0_rtx)); | |
1551 | } | |
1552 | else | |
1553 | undobuf.other_insn = 0; | |
1554 | } | |
1555 | #endif | |
1556 | } | |
1557 | else | |
1558 | #endif | |
1559 | { | |
1560 | n_occurrences = 0; /* `subst' counts here */ | |
1561 | ||
1562 | /* If I1 feeds into I2 (not into I3) and I1DEST is in I1SRC, we | |
1563 | need to make a unique copy of I2SRC each time we substitute it | |
1564 | to avoid self-referential rtl. */ | |
1565 | ||
d0ab8cd3 | 1566 | subst_low_cuid = INSN_CUID (i2); |
230d793d RS |
1567 | newpat = subst (PATTERN (i3), i2dest, i2src, 0, |
1568 | ! i1_feeds_i3 && i1dest_in_i1src); | |
1569 | previous_num_undos = undobuf.num_undo; | |
1570 | ||
1571 | /* Record whether i2's body now appears within i3's body. */ | |
1572 | i2_is_used = n_occurrences; | |
1573 | } | |
1574 | ||
1575 | /* If we already got a failure, don't try to do more. Otherwise, | |
1576 | try to substitute in I1 if we have it. */ | |
1577 | ||
1578 | if (i1 && GET_CODE (newpat) != CLOBBER) | |
1579 | { | |
1580 | /* Before we can do this substitution, we must redo the test done | |
1581 | above (see detailed comments there) that ensures that I1DEST | |
1582 | isn't mentioned in any SETs in NEWPAT that are field assignments. */ | |
1583 | ||
5f4f0e22 CH |
1584 | if (! combinable_i3pat (NULL_RTX, &newpat, i1dest, NULL_RTX, |
1585 | 0, NULL_PTR)) | |
230d793d RS |
1586 | { |
1587 | undo_all (); | |
1588 | return 0; | |
1589 | } | |
1590 | ||
1591 | n_occurrences = 0; | |
d0ab8cd3 | 1592 | subst_low_cuid = INSN_CUID (i1); |
230d793d RS |
1593 | newpat = subst (newpat, i1dest, i1src, 0, 0); |
1594 | previous_num_undos = undobuf.num_undo; | |
1595 | } | |
1596 | ||
916f14f1 RK |
1597 | /* Fail if an autoincrement side-effect has been duplicated. Be careful |
1598 | to count all the ways that I2SRC and I1SRC can be used. */ | |
5f4f0e22 | 1599 | if ((FIND_REG_INC_NOTE (i2, NULL_RTX) != 0 |
916f14f1 | 1600 | && i2_is_used + added_sets_2 > 1) |
5f4f0e22 | 1601 | || (i1 != 0 && FIND_REG_INC_NOTE (i1, NULL_RTX) != 0 |
916f14f1 RK |
1602 | && (n_occurrences + added_sets_1 + (added_sets_2 && ! i1_feeds_i3) |
1603 | > 1)) | |
230d793d RS |
1604 | /* Fail if we tried to make a new register (we used to abort, but there's |
1605 | really no reason to). */ | |
1606 | || max_reg_num () != maxreg | |
1607 | /* Fail if we couldn't do something and have a CLOBBER. */ | |
df7d75de RK |
1608 | || GET_CODE (newpat) == CLOBBER |
1609 | /* Fail if this new pattern is a MULT and we didn't have one before | |
1610 | at the outer level. */ | |
1611 | || (GET_CODE (newpat) == SET && GET_CODE (SET_SRC (newpat)) == MULT | |
1612 | && ! have_mult)) | |
230d793d RS |
1613 | { |
1614 | undo_all (); | |
1615 | return 0; | |
1616 | } | |
1617 | ||
1618 | /* If the actions of the earlier insns must be kept | |
1619 | in addition to substituting them into the latest one, | |
1620 | we must make a new PARALLEL for the latest insn | |
1621 | to hold additional the SETs. */ | |
1622 | ||
1623 | if (added_sets_1 || added_sets_2) | |
1624 | { | |
1625 | combine_extras++; | |
1626 | ||
1627 | if (GET_CODE (newpat) == PARALLEL) | |
1628 | { | |
1629 | rtvec old = XVEC (newpat, 0); | |
1630 | total_sets = XVECLEN (newpat, 0) + added_sets_1 + added_sets_2; | |
1631 | newpat = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (total_sets)); | |
4c9a05bc | 1632 | bcopy ((char *) &old->elem[0], (char *) &XVECEXP (newpat, 0, 0), |
230d793d RS |
1633 | sizeof (old->elem[0]) * old->num_elem); |
1634 | } | |
1635 | else | |
1636 | { | |
1637 | rtx old = newpat; | |
1638 | total_sets = 1 + added_sets_1 + added_sets_2; | |
1639 | newpat = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (total_sets)); | |
1640 | XVECEXP (newpat, 0, 0) = old; | |
1641 | } | |
1642 | ||
1643 | if (added_sets_1) | |
1644 | XVECEXP (newpat, 0, --total_sets) | |
1645 | = (GET_CODE (PATTERN (i1)) == PARALLEL | |
1646 | ? gen_rtx (SET, VOIDmode, i1dest, i1src) : PATTERN (i1)); | |
1647 | ||
1648 | if (added_sets_2) | |
1649 | { | |
1650 | /* If there is no I1, use I2's body as is. We used to also not do | |
1651 | the subst call below if I2 was substituted into I3, | |
1652 | but that could lose a simplification. */ | |
1653 | if (i1 == 0) | |
1654 | XVECEXP (newpat, 0, --total_sets) = i2pat; | |
1655 | else | |
1656 | /* See comment where i2pat is assigned. */ | |
1657 | XVECEXP (newpat, 0, --total_sets) | |
1658 | = subst (i2pat, i1dest, i1src, 0, 0); | |
1659 | } | |
1660 | } | |
1661 | ||
1662 | /* We come here when we are replacing a destination in I2 with the | |
1663 | destination of I3. */ | |
1664 | validate_replacement: | |
1665 | ||
6e25d159 RK |
1666 | /* Note which hard regs this insn has as inputs. */ |
1667 | mark_used_regs_combine (newpat); | |
1668 | ||
230d793d RS |
1669 | /* Is the result of combination a valid instruction? */ |
1670 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); | |
1671 | ||
1672 | /* If the result isn't valid, see if it is a PARALLEL of two SETs where | |
1673 | the second SET's destination is a register that is unused. In that case, | |
1674 | we just need the first SET. This can occur when simplifying a divmod | |
1675 | insn. We *must* test for this case here because the code below that | |
1676 | splits two independent SETs doesn't handle this case correctly when it | |
1677 | updates the register status. Also check the case where the first | |
1678 | SET's destination is unused. That would not cause incorrect code, but | |
1679 | does cause an unneeded insn to remain. */ | |
1680 | ||
1681 | if (insn_code_number < 0 && GET_CODE (newpat) == PARALLEL | |
1682 | && XVECLEN (newpat, 0) == 2 | |
1683 | && GET_CODE (XVECEXP (newpat, 0, 0)) == SET | |
1684 | && GET_CODE (XVECEXP (newpat, 0, 1)) == SET | |
1685 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) == REG | |
1686 | && find_reg_note (i3, REG_UNUSED, SET_DEST (XVECEXP (newpat, 0, 1))) | |
1687 | && ! side_effects_p (SET_SRC (XVECEXP (newpat, 0, 1))) | |
1688 | && asm_noperands (newpat) < 0) | |
1689 | { | |
1690 | newpat = XVECEXP (newpat, 0, 0); | |
1691 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); | |
1692 | } | |
1693 | ||
1694 | else if (insn_code_number < 0 && GET_CODE (newpat) == PARALLEL | |
1695 | && XVECLEN (newpat, 0) == 2 | |
1696 | && GET_CODE (XVECEXP (newpat, 0, 0)) == SET | |
1697 | && GET_CODE (XVECEXP (newpat, 0, 1)) == SET | |
1698 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) == REG | |
1699 | && find_reg_note (i3, REG_UNUSED, SET_DEST (XVECEXP (newpat, 0, 0))) | |
1700 | && ! side_effects_p (SET_SRC (XVECEXP (newpat, 0, 0))) | |
1701 | && asm_noperands (newpat) < 0) | |
1702 | { | |
1703 | newpat = XVECEXP (newpat, 0, 1); | |
1704 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); | |
1705 | } | |
1706 | ||
1707 | /* If we were combining three insns and the result is a simple SET | |
1708 | with no ASM_OPERANDS that wasn't recognized, try to split it into two | |
916f14f1 RK |
1709 | insns. There are two ways to do this. It can be split using a |
1710 | machine-specific method (like when you have an addition of a large | |
1711 | constant) or by combine in the function find_split_point. */ | |
1712 | ||
230d793d RS |
1713 | if (i1 && insn_code_number < 0 && GET_CODE (newpat) == SET |
1714 | && asm_noperands (newpat) < 0) | |
1715 | { | |
916f14f1 | 1716 | rtx m_split, *split; |
42495ca0 | 1717 | rtx ni2dest = i2dest; |
916f14f1 RK |
1718 | |
1719 | /* See if the MD file can split NEWPAT. If it can't, see if letting it | |
42495ca0 RK |
1720 | use I2DEST as a scratch register will help. In the latter case, |
1721 | convert I2DEST to the mode of the source of NEWPAT if we can. */ | |
916f14f1 RK |
1722 | |
1723 | m_split = split_insns (newpat, i3); | |
a70c61d9 JW |
1724 | |
1725 | /* We can only use I2DEST as a scratch reg if it doesn't overlap any | |
1726 | inputs of NEWPAT. */ | |
1727 | ||
1728 | /* ??? If I2DEST is not safe, and I1DEST exists, then it would be | |
1729 | possible to try that as a scratch reg. This would require adding | |
1730 | more code to make it work though. */ | |
1731 | ||
1732 | if (m_split == 0 && ! reg_overlap_mentioned_p (ni2dest, newpat)) | |
42495ca0 RK |
1733 | { |
1734 | /* If I2DEST is a hard register or the only use of a pseudo, | |
1735 | we can change its mode. */ | |
1736 | if (GET_MODE (SET_DEST (newpat)) != GET_MODE (i2dest) | |
02f4ada4 | 1737 | && GET_MODE (SET_DEST (newpat)) != VOIDmode |
60654f77 | 1738 | && GET_CODE (i2dest) == REG |
42495ca0 RK |
1739 | && (REGNO (i2dest) < FIRST_PSEUDO_REGISTER |
1740 | || (reg_n_sets[REGNO (i2dest)] == 1 && ! added_sets_2 | |
1741 | && ! REG_USERVAR_P (i2dest)))) | |
1742 | ni2dest = gen_rtx (REG, GET_MODE (SET_DEST (newpat)), | |
1743 | REGNO (i2dest)); | |
1744 | ||
1745 | m_split = split_insns (gen_rtx (PARALLEL, VOIDmode, | |
1746 | gen_rtvec (2, newpat, | |
1747 | gen_rtx (CLOBBER, | |
1748 | VOIDmode, | |
1749 | ni2dest))), | |
1750 | i3); | |
1751 | } | |
916f14f1 RK |
1752 | |
1753 | if (m_split && GET_CODE (m_split) == SEQUENCE | |
3f508eca RK |
1754 | && XVECLEN (m_split, 0) == 2 |
1755 | && (next_real_insn (i2) == i3 | |
1756 | || ! use_crosses_set_p (PATTERN (XVECEXP (m_split, 0, 0)), | |
1757 | INSN_CUID (i2)))) | |
916f14f1 | 1758 | { |
1a26b032 | 1759 | rtx i2set, i3set; |
d0ab8cd3 | 1760 | rtx newi3pat = PATTERN (XVECEXP (m_split, 0, 1)); |
916f14f1 | 1761 | newi2pat = PATTERN (XVECEXP (m_split, 0, 0)); |
916f14f1 | 1762 | |
e4ba89be RK |
1763 | i3set = single_set (XVECEXP (m_split, 0, 1)); |
1764 | i2set = single_set (XVECEXP (m_split, 0, 0)); | |
1a26b032 | 1765 | |
42495ca0 RK |
1766 | /* In case we changed the mode of I2DEST, replace it in the |
1767 | pseudo-register table here. We can't do it above in case this | |
1768 | code doesn't get executed and we do a split the other way. */ | |
1769 | ||
1770 | if (REGNO (i2dest) >= FIRST_PSEUDO_REGISTER) | |
1771 | SUBST (regno_reg_rtx[REGNO (i2dest)], ni2dest); | |
1772 | ||
916f14f1 | 1773 | i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); |
1a26b032 RK |
1774 | |
1775 | /* If I2 or I3 has multiple SETs, we won't know how to track | |
1776 | register status, so don't use these insns. */ | |
1777 | ||
1778 | if (i2_code_number >= 0 && i2set && i3set) | |
8888fada RK |
1779 | insn_code_number = recog_for_combine (&newi3pat, i3, |
1780 | &new_i3_notes); | |
c767f54b | 1781 | |
d0ab8cd3 RK |
1782 | if (insn_code_number >= 0) |
1783 | newpat = newi3pat; | |
1784 | ||
c767f54b | 1785 | /* It is possible that both insns now set the destination of I3. |
22609cbf | 1786 | If so, we must show an extra use of it. */ |
c767f54b | 1787 | |
1a26b032 RK |
1788 | if (insn_code_number >= 0 && GET_CODE (SET_DEST (i3set)) == REG |
1789 | && GET_CODE (SET_DEST (i2set)) == REG | |
1790 | && REGNO (SET_DEST (i3set)) == REGNO (SET_DEST (i2set))) | |
22609cbf | 1791 | reg_n_sets[REGNO (SET_DEST (i2set))]++; |
916f14f1 | 1792 | } |
230d793d RS |
1793 | |
1794 | /* If we can split it and use I2DEST, go ahead and see if that | |
1795 | helps things be recognized. Verify that none of the registers | |
1796 | are set between I2 and I3. */ | |
d0ab8cd3 | 1797 | if (insn_code_number < 0 && (split = find_split_point (&newpat, i3)) != 0 |
230d793d RS |
1798 | #ifdef HAVE_cc0 |
1799 | && GET_CODE (i2dest) == REG | |
1800 | #endif | |
1801 | /* We need I2DEST in the proper mode. If it is a hard register | |
1802 | or the only use of a pseudo, we can change its mode. */ | |
1803 | && (GET_MODE (*split) == GET_MODE (i2dest) | |
1804 | || GET_MODE (*split) == VOIDmode | |
1805 | || REGNO (i2dest) < FIRST_PSEUDO_REGISTER | |
1806 | || (reg_n_sets[REGNO (i2dest)] == 1 && ! added_sets_2 | |
1807 | && ! REG_USERVAR_P (i2dest))) | |
1808 | && (next_real_insn (i2) == i3 | |
1809 | || ! use_crosses_set_p (*split, INSN_CUID (i2))) | |
1810 | /* We can't overwrite I2DEST if its value is still used by | |
1811 | NEWPAT. */ | |
1812 | && ! reg_referenced_p (i2dest, newpat)) | |
1813 | { | |
1814 | rtx newdest = i2dest; | |
df7d75de RK |
1815 | enum rtx_code split_code = GET_CODE (*split); |
1816 | enum machine_mode split_mode = GET_MODE (*split); | |
230d793d RS |
1817 | |
1818 | /* Get NEWDEST as a register in the proper mode. We have already | |
1819 | validated that we can do this. */ | |
df7d75de | 1820 | if (GET_MODE (i2dest) != split_mode && split_mode != VOIDmode) |
230d793d | 1821 | { |
df7d75de | 1822 | newdest = gen_rtx (REG, split_mode, REGNO (i2dest)); |
230d793d RS |
1823 | |
1824 | if (REGNO (i2dest) >= FIRST_PSEUDO_REGISTER) | |
1825 | SUBST (regno_reg_rtx[REGNO (i2dest)], newdest); | |
1826 | } | |
1827 | ||
1828 | /* If *SPLIT is a (mult FOO (const_int pow2)), convert it to | |
1829 | an ASHIFT. This can occur if it was inside a PLUS and hence | |
1830 | appeared to be a memory address. This is a kludge. */ | |
df7d75de | 1831 | if (split_code == MULT |
230d793d RS |
1832 | && GET_CODE (XEXP (*split, 1)) == CONST_INT |
1833 | && (i = exact_log2 (INTVAL (XEXP (*split, 1)))) >= 0) | |
df7d75de | 1834 | SUBST (*split, gen_rtx_combine (ASHIFT, split_mode, |
5f4f0e22 | 1835 | XEXP (*split, 0), GEN_INT (i))); |
230d793d RS |
1836 | |
1837 | #ifdef INSN_SCHEDULING | |
1838 | /* If *SPLIT is a paradoxical SUBREG, when we split it, it should | |
1839 | be written as a ZERO_EXTEND. */ | |
df7d75de RK |
1840 | if (split_code == SUBREG && GET_CODE (SUBREG_REG (*split)) == MEM) |
1841 | SUBST (*split, gen_rtx_combine (ZERO_EXTEND, split_mode, | |
230d793d RS |
1842 | XEXP (*split, 0))); |
1843 | #endif | |
1844 | ||
1845 | newi2pat = gen_rtx_combine (SET, VOIDmode, newdest, *split); | |
1846 | SUBST (*split, newdest); | |
1847 | i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); | |
df7d75de RK |
1848 | |
1849 | /* If the split point was a MULT and we didn't have one before, | |
1850 | don't use one now. */ | |
1851 | if (i2_code_number >= 0 && ! (split_code == MULT && ! have_mult)) | |
230d793d RS |
1852 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); |
1853 | } | |
1854 | } | |
1855 | ||
1856 | /* Check for a case where we loaded from memory in a narrow mode and | |
1857 | then sign extended it, but we need both registers. In that case, | |
1858 | we have a PARALLEL with both loads from the same memory location. | |
1859 | We can split this into a load from memory followed by a register-register | |
1860 | copy. This saves at least one insn, more if register allocation can | |
f0343c74 RK |
1861 | eliminate the copy. |
1862 | ||
1863 | We cannot do this if the destination of the second assignment is | |
1864 | a register that we have already assumed is zero-extended. Similarly | |
1865 | for a SUBREG of such a register. */ | |
230d793d RS |
1866 | |
1867 | else if (i1 && insn_code_number < 0 && asm_noperands (newpat) < 0 | |
1868 | && GET_CODE (newpat) == PARALLEL | |
1869 | && XVECLEN (newpat, 0) == 2 | |
1870 | && GET_CODE (XVECEXP (newpat, 0, 0)) == SET | |
1871 | && GET_CODE (SET_SRC (XVECEXP (newpat, 0, 0))) == SIGN_EXTEND | |
1872 | && GET_CODE (XVECEXP (newpat, 0, 1)) == SET | |
1873 | && rtx_equal_p (SET_SRC (XVECEXP (newpat, 0, 1)), | |
1874 | XEXP (SET_SRC (XVECEXP (newpat, 0, 0)), 0)) | |
1875 | && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)), | |
1876 | INSN_CUID (i2)) | |
1877 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT | |
1878 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART | |
f0343c74 RK |
1879 | && ! (temp = SET_DEST (XVECEXP (newpat, 0, 1)), |
1880 | (GET_CODE (temp) == REG | |
1881 | && reg_nonzero_bits[REGNO (temp)] != 0 | |
1882 | && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD | |
1883 | && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT | |
1884 | && (reg_nonzero_bits[REGNO (temp)] | |
1885 | != GET_MODE_MASK (word_mode)))) | |
1886 | && ! (GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) == SUBREG | |
1887 | && (temp = SUBREG_REG (SET_DEST (XVECEXP (newpat, 0, 1))), | |
1888 | (GET_CODE (temp) == REG | |
1889 | && reg_nonzero_bits[REGNO (temp)] != 0 | |
1890 | && GET_MODE_BITSIZE (GET_MODE (temp)) < BITS_PER_WORD | |
1891 | && GET_MODE_BITSIZE (GET_MODE (temp)) < HOST_BITS_PER_INT | |
1892 | && (reg_nonzero_bits[REGNO (temp)] | |
1893 | != GET_MODE_MASK (word_mode))))) | |
230d793d RS |
1894 | && ! reg_overlap_mentioned_p (SET_DEST (XVECEXP (newpat, 0, 1)), |
1895 | SET_SRC (XVECEXP (newpat, 0, 1))) | |
1896 | && ! find_reg_note (i3, REG_UNUSED, | |
1897 | SET_DEST (XVECEXP (newpat, 0, 0)))) | |
1898 | { | |
472fbdd1 RK |
1899 | rtx ni2dest; |
1900 | ||
230d793d | 1901 | newi2pat = XVECEXP (newpat, 0, 0); |
472fbdd1 | 1902 | ni2dest = SET_DEST (XVECEXP (newpat, 0, 0)); |
230d793d RS |
1903 | newpat = XVECEXP (newpat, 0, 1); |
1904 | SUBST (SET_SRC (newpat), | |
472fbdd1 | 1905 | gen_lowpart_for_combine (GET_MODE (SET_SRC (newpat)), ni2dest)); |
230d793d RS |
1906 | i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); |
1907 | if (i2_code_number >= 0) | |
1908 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); | |
5089e22e RS |
1909 | |
1910 | if (insn_code_number >= 0) | |
1911 | { | |
1912 | rtx insn; | |
1913 | rtx link; | |
1914 | ||
1915 | /* If we will be able to accept this, we have made a change to the | |
1916 | destination of I3. This can invalidate a LOG_LINKS pointing | |
1917 | to I3. No other part of combine.c makes such a transformation. | |
1918 | ||
1919 | The new I3 will have a destination that was previously the | |
1920 | destination of I1 or I2 and which was used in i2 or I3. Call | |
1921 | distribute_links to make a LOG_LINK from the next use of | |
1922 | that destination. */ | |
1923 | ||
1924 | PATTERN (i3) = newpat; | |
5f4f0e22 | 1925 | distribute_links (gen_rtx (INSN_LIST, VOIDmode, i3, NULL_RTX)); |
5089e22e RS |
1926 | |
1927 | /* I3 now uses what used to be its destination and which is | |
1928 | now I2's destination. That means we need a LOG_LINK from | |
1929 | I3 to I2. But we used to have one, so we still will. | |
1930 | ||
1931 | However, some later insn might be using I2's dest and have | |
1932 | a LOG_LINK pointing at I3. We must remove this link. | |
1933 | The simplest way to remove the link is to point it at I1, | |
1934 | which we know will be a NOTE. */ | |
1935 | ||
1936 | for (insn = NEXT_INSN (i3); | |
0d4d42c3 RK |
1937 | insn && (this_basic_block == n_basic_blocks - 1 |
1938 | || insn != basic_block_head[this_basic_block + 1]); | |
5089e22e RS |
1939 | insn = NEXT_INSN (insn)) |
1940 | { | |
1941 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
472fbdd1 | 1942 | && reg_referenced_p (ni2dest, PATTERN (insn))) |
5089e22e RS |
1943 | { |
1944 | for (link = LOG_LINKS (insn); link; | |
1945 | link = XEXP (link, 1)) | |
1946 | if (XEXP (link, 0) == i3) | |
1947 | XEXP (link, 0) = i1; | |
1948 | ||
1949 | break; | |
1950 | } | |
1951 | } | |
1952 | } | |
230d793d RS |
1953 | } |
1954 | ||
1955 | /* Similarly, check for a case where we have a PARALLEL of two independent | |
1956 | SETs but we started with three insns. In this case, we can do the sets | |
1957 | as two separate insns. This case occurs when some SET allows two | |
1958 | other insns to combine, but the destination of that SET is still live. */ | |
1959 | ||
1960 | else if (i1 && insn_code_number < 0 && asm_noperands (newpat) < 0 | |
1961 | && GET_CODE (newpat) == PARALLEL | |
1962 | && XVECLEN (newpat, 0) == 2 | |
1963 | && GET_CODE (XVECEXP (newpat, 0, 0)) == SET | |
1964 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != ZERO_EXTRACT | |
1965 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != STRICT_LOW_PART | |
1966 | && GET_CODE (XVECEXP (newpat, 0, 1)) == SET | |
1967 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT | |
1968 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART | |
1969 | && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)), | |
1970 | INSN_CUID (i2)) | |
1971 | /* Don't pass sets with (USE (MEM ...)) dests to the following. */ | |
1972 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != USE | |
1973 | && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 0))) != USE | |
1974 | && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 1)), | |
1975 | XVECEXP (newpat, 0, 0)) | |
1976 | && ! reg_referenced_p (SET_DEST (XVECEXP (newpat, 0, 0)), | |
1977 | XVECEXP (newpat, 0, 1))) | |
1978 | { | |
1979 | newi2pat = XVECEXP (newpat, 0, 1); | |
1980 | newpat = XVECEXP (newpat, 0, 0); | |
1981 | ||
1982 | i2_code_number = recog_for_combine (&newi2pat, i2, &new_i2_notes); | |
1983 | if (i2_code_number >= 0) | |
1984 | insn_code_number = recog_for_combine (&newpat, i3, &new_i3_notes); | |
1985 | } | |
1986 | ||
1987 | /* If it still isn't recognized, fail and change things back the way they | |
1988 | were. */ | |
1989 | if ((insn_code_number < 0 | |
1990 | /* Is the result a reasonable ASM_OPERANDS? */ | |
1991 | && (! check_asm_operands (newpat) || added_sets_1 || added_sets_2))) | |
1992 | { | |
1993 | undo_all (); | |
1994 | return 0; | |
1995 | } | |
1996 | ||
1997 | /* If we had to change another insn, make sure it is valid also. */ | |
1998 | if (undobuf.other_insn) | |
1999 | { | |
230d793d RS |
2000 | rtx other_pat = PATTERN (undobuf.other_insn); |
2001 | rtx new_other_notes; | |
2002 | rtx note, next; | |
2003 | ||
6e25d159 RK |
2004 | CLEAR_HARD_REG_SET (newpat_used_regs); |
2005 | ||
230d793d RS |
2006 | other_code_number = recog_for_combine (&other_pat, undobuf.other_insn, |
2007 | &new_other_notes); | |
2008 | ||
2009 | if (other_code_number < 0 && ! check_asm_operands (other_pat)) | |
2010 | { | |
2011 | undo_all (); | |
2012 | return 0; | |
2013 | } | |
2014 | ||
2015 | PATTERN (undobuf.other_insn) = other_pat; | |
2016 | ||
2017 | /* If any of the notes in OTHER_INSN were REG_UNUSED, ensure that they | |
2018 | are still valid. Then add any non-duplicate notes added by | |
2019 | recog_for_combine. */ | |
2020 | for (note = REG_NOTES (undobuf.other_insn); note; note = next) | |
2021 | { | |
2022 | next = XEXP (note, 1); | |
2023 | ||
2024 | if (REG_NOTE_KIND (note) == REG_UNUSED | |
2025 | && ! reg_set_p (XEXP (note, 0), PATTERN (undobuf.other_insn))) | |
1a26b032 RK |
2026 | { |
2027 | if (GET_CODE (XEXP (note, 0)) == REG) | |
2028 | reg_n_deaths[REGNO (XEXP (note, 0))]--; | |
2029 | ||
2030 | remove_note (undobuf.other_insn, note); | |
2031 | } | |
230d793d RS |
2032 | } |
2033 | ||
1a26b032 RK |
2034 | for (note = new_other_notes; note; note = XEXP (note, 1)) |
2035 | if (GET_CODE (XEXP (note, 0)) == REG) | |
2036 | reg_n_deaths[REGNO (XEXP (note, 0))]++; | |
2037 | ||
230d793d | 2038 | distribute_notes (new_other_notes, undobuf.other_insn, |
5f4f0e22 | 2039 | undobuf.other_insn, NULL_RTX, NULL_RTX, NULL_RTX); |
230d793d RS |
2040 | } |
2041 | ||
2042 | /* We now know that we can do this combination. Merge the insns and | |
2043 | update the status of registers and LOG_LINKS. */ | |
2044 | ||
2045 | { | |
2046 | rtx i3notes, i2notes, i1notes = 0; | |
2047 | rtx i3links, i2links, i1links = 0; | |
2048 | rtx midnotes = 0; | |
230d793d RS |
2049 | register int regno; |
2050 | /* Compute which registers we expect to eliminate. */ | |
2051 | rtx elim_i2 = (newi2pat || i2dest_in_i2src || i2dest_in_i1src | |
2052 | ? 0 : i2dest); | |
2053 | rtx elim_i1 = i1 == 0 || i1dest_in_i1src ? 0 : i1dest; | |
2054 | ||
2055 | /* Get the old REG_NOTES and LOG_LINKS from all our insns and | |
2056 | clear them. */ | |
2057 | i3notes = REG_NOTES (i3), i3links = LOG_LINKS (i3); | |
2058 | i2notes = REG_NOTES (i2), i2links = LOG_LINKS (i2); | |
2059 | if (i1) | |
2060 | i1notes = REG_NOTES (i1), i1links = LOG_LINKS (i1); | |
2061 | ||
2062 | /* Ensure that we do not have something that should not be shared but | |
2063 | occurs multiple times in the new insns. Check this by first | |
5089e22e | 2064 | resetting all the `used' flags and then copying anything is shared. */ |
230d793d RS |
2065 | |
2066 | reset_used_flags (i3notes); | |
2067 | reset_used_flags (i2notes); | |
2068 | reset_used_flags (i1notes); | |
2069 | reset_used_flags (newpat); | |
2070 | reset_used_flags (newi2pat); | |
2071 | if (undobuf.other_insn) | |
2072 | reset_used_flags (PATTERN (undobuf.other_insn)); | |
2073 | ||
2074 | i3notes = copy_rtx_if_shared (i3notes); | |
2075 | i2notes = copy_rtx_if_shared (i2notes); | |
2076 | i1notes = copy_rtx_if_shared (i1notes); | |
2077 | newpat = copy_rtx_if_shared (newpat); | |
2078 | newi2pat = copy_rtx_if_shared (newi2pat); | |
2079 | if (undobuf.other_insn) | |
2080 | reset_used_flags (PATTERN (undobuf.other_insn)); | |
2081 | ||
2082 | INSN_CODE (i3) = insn_code_number; | |
2083 | PATTERN (i3) = newpat; | |
2084 | if (undobuf.other_insn) | |
2085 | INSN_CODE (undobuf.other_insn) = other_code_number; | |
2086 | ||
2087 | /* We had one special case above where I2 had more than one set and | |
2088 | we replaced a destination of one of those sets with the destination | |
2089 | of I3. In that case, we have to update LOG_LINKS of insns later | |
176c9e6b JW |
2090 | in this basic block. Note that this (expensive) case is rare. |
2091 | ||
2092 | Also, in this case, we must pretend that all REG_NOTEs for I2 | |
2093 | actually came from I3, so that REG_UNUSED notes from I2 will be | |
2094 | properly handled. */ | |
2095 | ||
2096 | if (i3_subst_into_i2) | |
2097 | { | |
2098 | for (i = 0; i < XVECLEN (PATTERN (i2), 0); i++) | |
2099 | if (GET_CODE (SET_DEST (XVECEXP (PATTERN (i2), 0, i))) == REG | |
2100 | && SET_DEST (XVECEXP (PATTERN (i2), 0, i)) != i2dest | |
2101 | && ! find_reg_note (i2, REG_UNUSED, | |
2102 | SET_DEST (XVECEXP (PATTERN (i2), 0, i)))) | |
2103 | for (temp = NEXT_INSN (i2); | |
2104 | temp && (this_basic_block == n_basic_blocks - 1 | |
2105 | || basic_block_head[this_basic_block] != temp); | |
2106 | temp = NEXT_INSN (temp)) | |
2107 | if (temp != i3 && GET_RTX_CLASS (GET_CODE (temp)) == 'i') | |
2108 | for (link = LOG_LINKS (temp); link; link = XEXP (link, 1)) | |
2109 | if (XEXP (link, 0) == i2) | |
2110 | XEXP (link, 0) = i3; | |
2111 | ||
2112 | if (i3notes) | |
2113 | { | |
2114 | rtx link = i3notes; | |
2115 | while (XEXP (link, 1)) | |
2116 | link = XEXP (link, 1); | |
2117 | XEXP (link, 1) = i2notes; | |
2118 | } | |
2119 | else | |
2120 | i3notes = i2notes; | |
2121 | i2notes = 0; | |
2122 | } | |
230d793d RS |
2123 | |
2124 | LOG_LINKS (i3) = 0; | |
2125 | REG_NOTES (i3) = 0; | |
2126 | LOG_LINKS (i2) = 0; | |
2127 | REG_NOTES (i2) = 0; | |
2128 | ||
2129 | if (newi2pat) | |
2130 | { | |
2131 | INSN_CODE (i2) = i2_code_number; | |
2132 | PATTERN (i2) = newi2pat; | |
2133 | } | |
2134 | else | |
2135 | { | |
2136 | PUT_CODE (i2, NOTE); | |
2137 | NOTE_LINE_NUMBER (i2) = NOTE_INSN_DELETED; | |
2138 | NOTE_SOURCE_FILE (i2) = 0; | |
2139 | } | |
2140 | ||
2141 | if (i1) | |
2142 | { | |
2143 | LOG_LINKS (i1) = 0; | |
2144 | REG_NOTES (i1) = 0; | |
2145 | PUT_CODE (i1, NOTE); | |
2146 | NOTE_LINE_NUMBER (i1) = NOTE_INSN_DELETED; | |
2147 | NOTE_SOURCE_FILE (i1) = 0; | |
2148 | } | |
2149 | ||
2150 | /* Get death notes for everything that is now used in either I3 or | |
2151 | I2 and used to die in a previous insn. */ | |
2152 | ||
2153 | move_deaths (newpat, i1 ? INSN_CUID (i1) : INSN_CUID (i2), i3, &midnotes); | |
2154 | if (newi2pat) | |
2155 | move_deaths (newi2pat, INSN_CUID (i1), i2, &midnotes); | |
2156 | ||
2157 | /* Distribute all the LOG_LINKS and REG_NOTES from I1, I2, and I3. */ | |
2158 | if (i3notes) | |
5f4f0e22 CH |
2159 | distribute_notes (i3notes, i3, i3, newi2pat ? i2 : NULL_RTX, |
2160 | elim_i2, elim_i1); | |
230d793d | 2161 | if (i2notes) |
5f4f0e22 CH |
2162 | distribute_notes (i2notes, i2, i3, newi2pat ? i2 : NULL_RTX, |
2163 | elim_i2, elim_i1); | |
230d793d | 2164 | if (i1notes) |
5f4f0e22 CH |
2165 | distribute_notes (i1notes, i1, i3, newi2pat ? i2 : NULL_RTX, |
2166 | elim_i2, elim_i1); | |
230d793d | 2167 | if (midnotes) |
5f4f0e22 CH |
2168 | distribute_notes (midnotes, NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, |
2169 | elim_i2, elim_i1); | |
230d793d RS |
2170 | |
2171 | /* Distribute any notes added to I2 or I3 by recog_for_combine. We | |
2172 | know these are REG_UNUSED and want them to go to the desired insn, | |
1a26b032 RK |
2173 | so we always pass it as i3. We have not counted the notes in |
2174 | reg_n_deaths yet, so we need to do so now. */ | |
2175 | ||
230d793d | 2176 | if (newi2pat && new_i2_notes) |
1a26b032 RK |
2177 | { |
2178 | for (temp = new_i2_notes; temp; temp = XEXP (temp, 1)) | |
2179 | if (GET_CODE (XEXP (temp, 0)) == REG) | |
2180 | reg_n_deaths[REGNO (XEXP (temp, 0))]++; | |
2181 | ||
2182 | distribute_notes (new_i2_notes, i2, i2, NULL_RTX, NULL_RTX, NULL_RTX); | |
2183 | } | |
2184 | ||
230d793d | 2185 | if (new_i3_notes) |
1a26b032 RK |
2186 | { |
2187 | for (temp = new_i3_notes; temp; temp = XEXP (temp, 1)) | |
2188 | if (GET_CODE (XEXP (temp, 0)) == REG) | |
2189 | reg_n_deaths[REGNO (XEXP (temp, 0))]++; | |
2190 | ||
2191 | distribute_notes (new_i3_notes, i3, i3, NULL_RTX, NULL_RTX, NULL_RTX); | |
2192 | } | |
230d793d RS |
2193 | |
2194 | /* If I3DEST was used in I3SRC, it really died in I3. We may need to | |
1a26b032 RK |
2195 | put a REG_DEAD note for it somewhere. Similarly for I2 and I1. |
2196 | Show an additional death due to the REG_DEAD note we make here. If | |
2197 | we discard it in distribute_notes, we will decrement it again. */ | |
d0ab8cd3 | 2198 | |
230d793d | 2199 | if (i3dest_killed) |
1a26b032 RK |
2200 | { |
2201 | if (GET_CODE (i3dest_killed) == REG) | |
2202 | reg_n_deaths[REGNO (i3dest_killed)]++; | |
2203 | ||
2204 | distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i3dest_killed, | |
2205 | NULL_RTX), | |
2206 | NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, | |
2207 | NULL_RTX, NULL_RTX); | |
2208 | } | |
58c8c593 RK |
2209 | |
2210 | /* For I2 and I1, we have to be careful. If NEWI2PAT exists and sets | |
2211 | I2DEST or I1DEST, the death must be somewhere before I2, not I3. If | |
2212 | we passed I3 in that case, it might delete I2. */ | |
2213 | ||
230d793d | 2214 | if (i2dest_in_i2src) |
58c8c593 | 2215 | { |
1a26b032 RK |
2216 | if (GET_CODE (i2dest) == REG) |
2217 | reg_n_deaths[REGNO (i2dest)]++; | |
2218 | ||
58c8c593 RK |
2219 | if (newi2pat && reg_set_p (i2dest, newi2pat)) |
2220 | distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i2dest, NULL_RTX), | |
2221 | NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX); | |
2222 | else | |
2223 | distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i2dest, NULL_RTX), | |
2224 | NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, | |
2225 | NULL_RTX, NULL_RTX); | |
2226 | } | |
2227 | ||
230d793d | 2228 | if (i1dest_in_i1src) |
58c8c593 | 2229 | { |
1a26b032 RK |
2230 | if (GET_CODE (i1dest) == REG) |
2231 | reg_n_deaths[REGNO (i1dest)]++; | |
2232 | ||
58c8c593 RK |
2233 | if (newi2pat && reg_set_p (i1dest, newi2pat)) |
2234 | distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i1dest, NULL_RTX), | |
2235 | NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX); | |
2236 | else | |
2237 | distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i1dest, NULL_RTX), | |
2238 | NULL_RTX, i3, newi2pat ? i2 : NULL_RTX, | |
2239 | NULL_RTX, NULL_RTX); | |
2240 | } | |
230d793d RS |
2241 | |
2242 | distribute_links (i3links); | |
2243 | distribute_links (i2links); | |
2244 | distribute_links (i1links); | |
2245 | ||
2246 | if (GET_CODE (i2dest) == REG) | |
2247 | { | |
d0ab8cd3 RK |
2248 | rtx link; |
2249 | rtx i2_insn = 0, i2_val = 0, set; | |
2250 | ||
2251 | /* The insn that used to set this register doesn't exist, and | |
2252 | this life of the register may not exist either. See if one of | |
2253 | I3's links points to an insn that sets I2DEST. If it does, | |
2254 | that is now the last known value for I2DEST. If we don't update | |
2255 | this and I2 set the register to a value that depended on its old | |
230d793d RS |
2256 | contents, we will get confused. If this insn is used, thing |
2257 | will be set correctly in combine_instructions. */ | |
d0ab8cd3 RK |
2258 | |
2259 | for (link = LOG_LINKS (i3); link; link = XEXP (link, 1)) | |
2260 | if ((set = single_set (XEXP (link, 0))) != 0 | |
2261 | && rtx_equal_p (i2dest, SET_DEST (set))) | |
2262 | i2_insn = XEXP (link, 0), i2_val = SET_SRC (set); | |
2263 | ||
2264 | record_value_for_reg (i2dest, i2_insn, i2_val); | |
230d793d RS |
2265 | |
2266 | /* If the reg formerly set in I2 died only once and that was in I3, | |
2267 | zero its use count so it won't make `reload' do any work. */ | |
5af91171 | 2268 | if (! added_sets_2 && newi2pat == 0 && ! i2dest_in_i2src) |
230d793d RS |
2269 | { |
2270 | regno = REGNO (i2dest); | |
2271 | reg_n_sets[regno]--; | |
2272 | if (reg_n_sets[regno] == 0 | |
5f4f0e22 CH |
2273 | && ! (basic_block_live_at_start[0][regno / REGSET_ELT_BITS] |
2274 | & ((REGSET_ELT_TYPE) 1 << (regno % REGSET_ELT_BITS)))) | |
230d793d RS |
2275 | reg_n_refs[regno] = 0; |
2276 | } | |
2277 | } | |
2278 | ||
2279 | if (i1 && GET_CODE (i1dest) == REG) | |
2280 | { | |
d0ab8cd3 RK |
2281 | rtx link; |
2282 | rtx i1_insn = 0, i1_val = 0, set; | |
2283 | ||
2284 | for (link = LOG_LINKS (i3); link; link = XEXP (link, 1)) | |
2285 | if ((set = single_set (XEXP (link, 0))) != 0 | |
2286 | && rtx_equal_p (i1dest, SET_DEST (set))) | |
2287 | i1_insn = XEXP (link, 0), i1_val = SET_SRC (set); | |
2288 | ||
2289 | record_value_for_reg (i1dest, i1_insn, i1_val); | |
2290 | ||
230d793d | 2291 | regno = REGNO (i1dest); |
5af91171 | 2292 | if (! added_sets_1 && ! i1dest_in_i1src) |
230d793d RS |
2293 | { |
2294 | reg_n_sets[regno]--; | |
2295 | if (reg_n_sets[regno] == 0 | |
5f4f0e22 CH |
2296 | && ! (basic_block_live_at_start[0][regno / REGSET_ELT_BITS] |
2297 | & ((REGSET_ELT_TYPE) 1 << (regno % REGSET_ELT_BITS)))) | |
230d793d RS |
2298 | reg_n_refs[regno] = 0; |
2299 | } | |
2300 | } | |
2301 | ||
951553af | 2302 | /* Update reg_nonzero_bits et al for any changes that may have been made |
22609cbf RK |
2303 | to this insn. */ |
2304 | ||
951553af | 2305 | note_stores (newpat, set_nonzero_bits_and_sign_copies); |
22609cbf | 2306 | if (newi2pat) |
951553af | 2307 | note_stores (newi2pat, set_nonzero_bits_and_sign_copies); |
22609cbf | 2308 | |
230d793d RS |
2309 | /* If I3 is now an unconditional jump, ensure that it has a |
2310 | BARRIER following it since it may have initially been a | |
381ee8af | 2311 | conditional jump. It may also be the last nonnote insn. */ |
230d793d RS |
2312 | |
2313 | if ((GET_CODE (newpat) == RETURN || simplejump_p (i3)) | |
381ee8af TW |
2314 | && ((temp = next_nonnote_insn (i3)) == NULL_RTX |
2315 | || GET_CODE (temp) != BARRIER)) | |
230d793d RS |
2316 | emit_barrier_after (i3); |
2317 | } | |
2318 | ||
2319 | combine_successes++; | |
2320 | ||
abe6e52f RK |
2321 | if (added_links_insn |
2322 | && (newi2pat == 0 || INSN_CUID (added_links_insn) < INSN_CUID (i2)) | |
2323 | && INSN_CUID (added_links_insn) < INSN_CUID (i3)) | |
2324 | return added_links_insn; | |
2325 | else | |
2326 | return newi2pat ? i2 : i3; | |
230d793d RS |
2327 | } |
2328 | \f | |
2329 | /* Undo all the modifications recorded in undobuf. */ | |
2330 | ||
2331 | static void | |
2332 | undo_all () | |
2333 | { | |
2334 | register int i; | |
2335 | if (undobuf.num_undo > MAX_UNDO) | |
2336 | undobuf.num_undo = MAX_UNDO; | |
2337 | for (i = undobuf.num_undo - 1; i >= 0; i--) | |
7c046e4e RK |
2338 | { |
2339 | if (undobuf.undo[i].is_int) | |
2340 | *undobuf.undo[i].where.i = undobuf.undo[i].old_contents.i; | |
2341 | else | |
f5393ab9 | 2342 | *undobuf.undo[i].where.r = undobuf.undo[i].old_contents.r; |
7c046e4e RK |
2343 | |
2344 | } | |
230d793d RS |
2345 | |
2346 | obfree (undobuf.storage); | |
2347 | undobuf.num_undo = 0; | |
2348 | } | |
2349 | \f | |
2350 | /* Find the innermost point within the rtx at LOC, possibly LOC itself, | |
d0ab8cd3 RK |
2351 | where we have an arithmetic expression and return that point. LOC will |
2352 | be inside INSN. | |
230d793d RS |
2353 | |
2354 | try_combine will call this function to see if an insn can be split into | |
2355 | two insns. */ | |
2356 | ||
2357 | static rtx * | |
d0ab8cd3 | 2358 | find_split_point (loc, insn) |
230d793d | 2359 | rtx *loc; |
d0ab8cd3 | 2360 | rtx insn; |
230d793d RS |
2361 | { |
2362 | rtx x = *loc; | |
2363 | enum rtx_code code = GET_CODE (x); | |
2364 | rtx *split; | |
2365 | int len = 0, pos, unsignedp; | |
2366 | rtx inner; | |
2367 | ||
2368 | /* First special-case some codes. */ | |
2369 | switch (code) | |
2370 | { | |
2371 | case SUBREG: | |
2372 | #ifdef INSN_SCHEDULING | |
2373 | /* If we are making a paradoxical SUBREG invalid, it becomes a split | |
2374 | point. */ | |
2375 | if (GET_CODE (SUBREG_REG (x)) == MEM) | |
2376 | return loc; | |
2377 | #endif | |
d0ab8cd3 | 2378 | return find_split_point (&SUBREG_REG (x), insn); |
230d793d | 2379 | |
230d793d | 2380 | case MEM: |
916f14f1 | 2381 | #ifdef HAVE_lo_sum |
230d793d RS |
2382 | /* If we have (mem (const ..)) or (mem (symbol_ref ...)), split it |
2383 | using LO_SUM and HIGH. */ | |
2384 | if (GET_CODE (XEXP (x, 0)) == CONST | |
2385 | || GET_CODE (XEXP (x, 0)) == SYMBOL_REF) | |
2386 | { | |
2387 | SUBST (XEXP (x, 0), | |
2388 | gen_rtx_combine (LO_SUM, Pmode, | |
2389 | gen_rtx_combine (HIGH, Pmode, XEXP (x, 0)), | |
2390 | XEXP (x, 0))); | |
2391 | return &XEXP (XEXP (x, 0), 0); | |
2392 | } | |
230d793d RS |
2393 | #endif |
2394 | ||
916f14f1 RK |
2395 | /* If we have a PLUS whose second operand is a constant and the |
2396 | address is not valid, perhaps will can split it up using | |
2397 | the machine-specific way to split large constants. We use | |
d0ab8cd3 | 2398 | the first psuedo-reg (one of the virtual regs) as a placeholder; |
916f14f1 RK |
2399 | it will not remain in the result. */ |
2400 | if (GET_CODE (XEXP (x, 0)) == PLUS | |
2401 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
2402 | && ! memory_address_p (GET_MODE (x), XEXP (x, 0))) | |
2403 | { | |
2404 | rtx reg = regno_reg_rtx[FIRST_PSEUDO_REGISTER]; | |
2405 | rtx seq = split_insns (gen_rtx (SET, VOIDmode, reg, XEXP (x, 0)), | |
2406 | subst_insn); | |
2407 | ||
2408 | /* This should have produced two insns, each of which sets our | |
2409 | placeholder. If the source of the second is a valid address, | |
2410 | we can make put both sources together and make a split point | |
2411 | in the middle. */ | |
2412 | ||
2413 | if (seq && XVECLEN (seq, 0) == 2 | |
2414 | && GET_CODE (XVECEXP (seq, 0, 0)) == INSN | |
2415 | && GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) == SET | |
2416 | && SET_DEST (PATTERN (XVECEXP (seq, 0, 0))) == reg | |
2417 | && ! reg_mentioned_p (reg, | |
2418 | SET_SRC (PATTERN (XVECEXP (seq, 0, 0)))) | |
2419 | && GET_CODE (XVECEXP (seq, 0, 1)) == INSN | |
2420 | && GET_CODE (PATTERN (XVECEXP (seq, 0, 1))) == SET | |
2421 | && SET_DEST (PATTERN (XVECEXP (seq, 0, 1))) == reg | |
2422 | && memory_address_p (GET_MODE (x), | |
2423 | SET_SRC (PATTERN (XVECEXP (seq, 0, 1))))) | |
2424 | { | |
2425 | rtx src1 = SET_SRC (PATTERN (XVECEXP (seq, 0, 0))); | |
2426 | rtx src2 = SET_SRC (PATTERN (XVECEXP (seq, 0, 1))); | |
2427 | ||
2428 | /* Replace the placeholder in SRC2 with SRC1. If we can | |
2429 | find where in SRC2 it was placed, that can become our | |
2430 | split point and we can replace this address with SRC2. | |
2431 | Just try two obvious places. */ | |
2432 | ||
2433 | src2 = replace_rtx (src2, reg, src1); | |
2434 | split = 0; | |
2435 | if (XEXP (src2, 0) == src1) | |
2436 | split = &XEXP (src2, 0); | |
2437 | else if (GET_RTX_FORMAT (GET_CODE (XEXP (src2, 0)))[0] == 'e' | |
2438 | && XEXP (XEXP (src2, 0), 0) == src1) | |
2439 | split = &XEXP (XEXP (src2, 0), 0); | |
2440 | ||
2441 | if (split) | |
2442 | { | |
2443 | SUBST (XEXP (x, 0), src2); | |
2444 | return split; | |
2445 | } | |
2446 | } | |
1a26b032 RK |
2447 | |
2448 | /* If that didn't work, perhaps the first operand is complex and | |
2449 | needs to be computed separately, so make a split point there. | |
2450 | This will occur on machines that just support REG + CONST | |
2451 | and have a constant moved through some previous computation. */ | |
2452 | ||
2453 | else if (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (x, 0), 0))) != 'o' | |
2454 | && ! (GET_CODE (XEXP (XEXP (x, 0), 0)) == SUBREG | |
2455 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (XEXP (x, 0), 0)))) | |
2456 | == 'o'))) | |
2457 | return &XEXP (XEXP (x, 0), 0); | |
916f14f1 RK |
2458 | } |
2459 | break; | |
2460 | ||
230d793d RS |
2461 | case SET: |
2462 | #ifdef HAVE_cc0 | |
2463 | /* If SET_DEST is CC0 and SET_SRC is not an operand, a COMPARE, or a | |
2464 | ZERO_EXTRACT, the most likely reason why this doesn't match is that | |
2465 | we need to put the operand into a register. So split at that | |
2466 | point. */ | |
2467 | ||
2468 | if (SET_DEST (x) == cc0_rtx | |
2469 | && GET_CODE (SET_SRC (x)) != COMPARE | |
2470 | && GET_CODE (SET_SRC (x)) != ZERO_EXTRACT | |
2471 | && GET_RTX_CLASS (GET_CODE (SET_SRC (x))) != 'o' | |
2472 | && ! (GET_CODE (SET_SRC (x)) == SUBREG | |
2473 | && GET_RTX_CLASS (GET_CODE (SUBREG_REG (SET_SRC (x)))) == 'o')) | |
2474 | return &SET_SRC (x); | |
2475 | #endif | |
2476 | ||
2477 | /* See if we can split SET_SRC as it stands. */ | |
d0ab8cd3 | 2478 | split = find_split_point (&SET_SRC (x), insn); |
230d793d RS |
2479 | if (split && split != &SET_SRC (x)) |
2480 | return split; | |
2481 | ||
2482 | /* See if this is a bitfield assignment with everything constant. If | |
2483 | so, this is an IOR of an AND, so split it into that. */ | |
2484 | if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT | |
2485 | && (GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0))) | |
5f4f0e22 | 2486 | <= HOST_BITS_PER_WIDE_INT) |
230d793d RS |
2487 | && GET_CODE (XEXP (SET_DEST (x), 1)) == CONST_INT |
2488 | && GET_CODE (XEXP (SET_DEST (x), 2)) == CONST_INT | |
2489 | && GET_CODE (SET_SRC (x)) == CONST_INT | |
2490 | && ((INTVAL (XEXP (SET_DEST (x), 1)) | |
2491 | + INTVAL (XEXP (SET_DEST (x), 2))) | |
2492 | <= GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0)))) | |
2493 | && ! side_effects_p (XEXP (SET_DEST (x), 0))) | |
2494 | { | |
2495 | int pos = INTVAL (XEXP (SET_DEST (x), 2)); | |
2496 | int len = INTVAL (XEXP (SET_DEST (x), 1)); | |
2497 | int src = INTVAL (SET_SRC (x)); | |
2498 | rtx dest = XEXP (SET_DEST (x), 0); | |
2499 | enum machine_mode mode = GET_MODE (dest); | |
5f4f0e22 | 2500 | unsigned HOST_WIDE_INT mask = ((HOST_WIDE_INT) 1 << len) - 1; |
230d793d RS |
2501 | |
2502 | #if BITS_BIG_ENDIAN | |
2503 | pos = GET_MODE_BITSIZE (mode) - len - pos; | |
2504 | #endif | |
2505 | ||
2506 | if (src == mask) | |
2507 | SUBST (SET_SRC (x), | |
5f4f0e22 | 2508 | gen_binary (IOR, mode, dest, GEN_INT (src << pos))); |
230d793d RS |
2509 | else |
2510 | SUBST (SET_SRC (x), | |
2511 | gen_binary (IOR, mode, | |
2512 | gen_binary (AND, mode, dest, | |
5f4f0e22 CH |
2513 | GEN_INT (~ (mask << pos) |
2514 | & GET_MODE_MASK (mode))), | |
2515 | GEN_INT (src << pos))); | |
230d793d RS |
2516 | |
2517 | SUBST (SET_DEST (x), dest); | |
2518 | ||
d0ab8cd3 | 2519 | split = find_split_point (&SET_SRC (x), insn); |
230d793d RS |
2520 | if (split && split != &SET_SRC (x)) |
2521 | return split; | |
2522 | } | |
2523 | ||
2524 | /* Otherwise, see if this is an operation that we can split into two. | |
2525 | If so, try to split that. */ | |
2526 | code = GET_CODE (SET_SRC (x)); | |
2527 | ||
2528 | switch (code) | |
2529 | { | |
d0ab8cd3 RK |
2530 | case AND: |
2531 | /* If we are AND'ing with a large constant that is only a single | |
2532 | bit and the result is only being used in a context where we | |
2533 | need to know if it is zero or non-zero, replace it with a bit | |
2534 | extraction. This will avoid the large constant, which might | |
2535 | have taken more than one insn to make. If the constant were | |
2536 | not a valid argument to the AND but took only one insn to make, | |
2537 | this is no worse, but if it took more than one insn, it will | |
2538 | be better. */ | |
2539 | ||
2540 | if (GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT | |
2541 | && GET_CODE (XEXP (SET_SRC (x), 0)) == REG | |
2542 | && (pos = exact_log2 (INTVAL (XEXP (SET_SRC (x), 1)))) >= 7 | |
2543 | && GET_CODE (SET_DEST (x)) == REG | |
2544 | && (split = find_single_use (SET_DEST (x), insn, NULL_PTR)) != 0 | |
2545 | && (GET_CODE (*split) == EQ || GET_CODE (*split) == NE) | |
2546 | && XEXP (*split, 0) == SET_DEST (x) | |
2547 | && XEXP (*split, 1) == const0_rtx) | |
2548 | { | |
2549 | SUBST (SET_SRC (x), | |
2550 | make_extraction (GET_MODE (SET_DEST (x)), | |
2551 | XEXP (SET_SRC (x), 0), | |
2552 | pos, NULL_RTX, 1, 1, 0, 0)); | |
2553 | return find_split_point (loc, insn); | |
2554 | } | |
2555 | break; | |
2556 | ||
230d793d RS |
2557 | case SIGN_EXTEND: |
2558 | inner = XEXP (SET_SRC (x), 0); | |
2559 | pos = 0; | |
2560 | len = GET_MODE_BITSIZE (GET_MODE (inner)); | |
2561 | unsignedp = 0; | |
2562 | break; | |
2563 | ||
2564 | case SIGN_EXTRACT: | |
2565 | case ZERO_EXTRACT: | |
2566 | if (GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT | |
2567 | && GET_CODE (XEXP (SET_SRC (x), 2)) == CONST_INT) | |
2568 | { | |
2569 | inner = XEXP (SET_SRC (x), 0); | |
2570 | len = INTVAL (XEXP (SET_SRC (x), 1)); | |
2571 | pos = INTVAL (XEXP (SET_SRC (x), 2)); | |
2572 | ||
2573 | #if BITS_BIG_ENDIAN | |
2574 | pos = GET_MODE_BITSIZE (GET_MODE (inner)) - len - pos; | |
2575 | #endif | |
2576 | unsignedp = (code == ZERO_EXTRACT); | |
2577 | } | |
2578 | break; | |
2579 | } | |
2580 | ||
2581 | if (len && pos >= 0 && pos + len <= GET_MODE_BITSIZE (GET_MODE (inner))) | |
2582 | { | |
2583 | enum machine_mode mode = GET_MODE (SET_SRC (x)); | |
2584 | ||
d0ab8cd3 RK |
2585 | /* For unsigned, we have a choice of a shift followed by an |
2586 | AND or two shifts. Use two shifts for field sizes where the | |
2587 | constant might be too large. We assume here that we can | |
2588 | always at least get 8-bit constants in an AND insn, which is | |
2589 | true for every current RISC. */ | |
2590 | ||
2591 | if (unsignedp && len <= 8) | |
230d793d RS |
2592 | { |
2593 | SUBST (SET_SRC (x), | |
2594 | gen_rtx_combine | |
2595 | (AND, mode, | |
2596 | gen_rtx_combine (LSHIFTRT, mode, | |
2597 | gen_lowpart_for_combine (mode, inner), | |
5f4f0e22 CH |
2598 | GEN_INT (pos)), |
2599 | GEN_INT (((HOST_WIDE_INT) 1 << len) - 1))); | |
230d793d | 2600 | |
d0ab8cd3 | 2601 | split = find_split_point (&SET_SRC (x), insn); |
230d793d RS |
2602 | if (split && split != &SET_SRC (x)) |
2603 | return split; | |
2604 | } | |
2605 | else | |
2606 | { | |
2607 | SUBST (SET_SRC (x), | |
2608 | gen_rtx_combine | |
d0ab8cd3 | 2609 | (unsignedp ? LSHIFTRT : ASHIFTRT, mode, |
230d793d RS |
2610 | gen_rtx_combine (ASHIFT, mode, |
2611 | gen_lowpart_for_combine (mode, inner), | |
5f4f0e22 CH |
2612 | GEN_INT (GET_MODE_BITSIZE (mode) |
2613 | - len - pos)), | |
2614 | GEN_INT (GET_MODE_BITSIZE (mode) - len))); | |
230d793d | 2615 | |
d0ab8cd3 | 2616 | split = find_split_point (&SET_SRC (x), insn); |
230d793d RS |
2617 | if (split && split != &SET_SRC (x)) |
2618 | return split; | |
2619 | } | |
2620 | } | |
2621 | ||
2622 | /* See if this is a simple operation with a constant as the second | |
2623 | operand. It might be that this constant is out of range and hence | |
2624 | could be used as a split point. */ | |
2625 | if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '2' | |
2626 | || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == 'c' | |
2627 | || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '<') | |
2628 | && CONSTANT_P (XEXP (SET_SRC (x), 1)) | |
2629 | && (GET_RTX_CLASS (GET_CODE (XEXP (SET_SRC (x), 0))) == 'o' | |
2630 | || (GET_CODE (XEXP (SET_SRC (x), 0)) == SUBREG | |
2631 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (SET_SRC (x), 0)))) | |
2632 | == 'o')))) | |
2633 | return &XEXP (SET_SRC (x), 1); | |
2634 | ||
2635 | /* Finally, see if this is a simple operation with its first operand | |
2636 | not in a register. The operation might require this operand in a | |
2637 | register, so return it as a split point. We can always do this | |
2638 | because if the first operand were another operation, we would have | |
2639 | already found it as a split point. */ | |
2640 | if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '2' | |
2641 | || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == 'c' | |
2642 | || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '<' | |
2643 | || GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '1') | |
2644 | && ! register_operand (XEXP (SET_SRC (x), 0), VOIDmode)) | |
2645 | return &XEXP (SET_SRC (x), 0); | |
2646 | ||
2647 | return 0; | |
2648 | ||
2649 | case AND: | |
2650 | case IOR: | |
2651 | /* We write NOR as (and (not A) (not B)), but if we don't have a NOR, | |
2652 | it is better to write this as (not (ior A B)) so we can split it. | |
2653 | Similarly for IOR. */ | |
2654 | if (GET_CODE (XEXP (x, 0)) == NOT && GET_CODE (XEXP (x, 1)) == NOT) | |
2655 | { | |
2656 | SUBST (*loc, | |
2657 | gen_rtx_combine (NOT, GET_MODE (x), | |
2658 | gen_rtx_combine (code == IOR ? AND : IOR, | |
2659 | GET_MODE (x), | |
2660 | XEXP (XEXP (x, 0), 0), | |
2661 | XEXP (XEXP (x, 1), 0)))); | |
d0ab8cd3 | 2662 | return find_split_point (loc, insn); |
230d793d RS |
2663 | } |
2664 | ||
2665 | /* Many RISC machines have a large set of logical insns. If the | |
2666 | second operand is a NOT, put it first so we will try to split the | |
2667 | other operand first. */ | |
2668 | if (GET_CODE (XEXP (x, 1)) == NOT) | |
2669 | { | |
2670 | rtx tem = XEXP (x, 0); | |
2671 | SUBST (XEXP (x, 0), XEXP (x, 1)); | |
2672 | SUBST (XEXP (x, 1), tem); | |
2673 | } | |
2674 | break; | |
2675 | } | |
2676 | ||
2677 | /* Otherwise, select our actions depending on our rtx class. */ | |
2678 | switch (GET_RTX_CLASS (code)) | |
2679 | { | |
2680 | case 'b': /* This is ZERO_EXTRACT and SIGN_EXTRACT. */ | |
2681 | case '3': | |
d0ab8cd3 | 2682 | split = find_split_point (&XEXP (x, 2), insn); |
230d793d RS |
2683 | if (split) |
2684 | return split; | |
2685 | /* ... fall through ... */ | |
2686 | case '2': | |
2687 | case 'c': | |
2688 | case '<': | |
d0ab8cd3 | 2689 | split = find_split_point (&XEXP (x, 1), insn); |
230d793d RS |
2690 | if (split) |
2691 | return split; | |
2692 | /* ... fall through ... */ | |
2693 | case '1': | |
2694 | /* Some machines have (and (shift ...) ...) insns. If X is not | |
2695 | an AND, but XEXP (X, 0) is, use it as our split point. */ | |
2696 | if (GET_CODE (x) != AND && GET_CODE (XEXP (x, 0)) == AND) | |
2697 | return &XEXP (x, 0); | |
2698 | ||
d0ab8cd3 | 2699 | split = find_split_point (&XEXP (x, 0), insn); |
230d793d RS |
2700 | if (split) |
2701 | return split; | |
2702 | return loc; | |
2703 | } | |
2704 | ||
2705 | /* Otherwise, we don't have a split point. */ | |
2706 | return 0; | |
2707 | } | |
2708 | \f | |
2709 | /* Throughout X, replace FROM with TO, and return the result. | |
2710 | The result is TO if X is FROM; | |
2711 | otherwise the result is X, but its contents may have been modified. | |
2712 | If they were modified, a record was made in undobuf so that | |
2713 | undo_all will (among other things) return X to its original state. | |
2714 | ||
2715 | If the number of changes necessary is too much to record to undo, | |
2716 | the excess changes are not made, so the result is invalid. | |
2717 | The changes already made can still be undone. | |
2718 | undobuf.num_undo is incremented for such changes, so by testing that | |
2719 | the caller can tell whether the result is valid. | |
2720 | ||
2721 | `n_occurrences' is incremented each time FROM is replaced. | |
2722 | ||
2723 | IN_DEST is non-zero if we are processing the SET_DEST of a SET. | |
2724 | ||
5089e22e | 2725 | UNIQUE_COPY is non-zero if each substitution must be unique. We do this |
230d793d RS |
2726 | by copying if `n_occurrences' is non-zero. */ |
2727 | ||
2728 | static rtx | |
2729 | subst (x, from, to, in_dest, unique_copy) | |
2730 | register rtx x, from, to; | |
2731 | int in_dest; | |
2732 | int unique_copy; | |
2733 | { | |
f24ad0e4 | 2734 | register enum rtx_code code = GET_CODE (x); |
230d793d | 2735 | enum machine_mode op0_mode = VOIDmode; |
8079805d RK |
2736 | register char *fmt; |
2737 | register int len, i; | |
2738 | rtx new; | |
230d793d RS |
2739 | |
2740 | /* Two expressions are equal if they are identical copies of a shared | |
2741 | RTX or if they are both registers with the same register number | |
2742 | and mode. */ | |
2743 | ||
2744 | #define COMBINE_RTX_EQUAL_P(X,Y) \ | |
2745 | ((X) == (Y) \ | |
2746 | || (GET_CODE (X) == REG && GET_CODE (Y) == REG \ | |
2747 | && REGNO (X) == REGNO (Y) && GET_MODE (X) == GET_MODE (Y))) | |
2748 | ||
2749 | if (! in_dest && COMBINE_RTX_EQUAL_P (x, from)) | |
2750 | { | |
2751 | n_occurrences++; | |
2752 | return (unique_copy && n_occurrences > 1 ? copy_rtx (to) : to); | |
2753 | } | |
2754 | ||
2755 | /* If X and FROM are the same register but different modes, they will | |
2756 | not have been seen as equal above. However, flow.c will make a | |
2757 | LOG_LINKS entry for that case. If we do nothing, we will try to | |
2758 | rerecognize our original insn and, when it succeeds, we will | |
2759 | delete the feeding insn, which is incorrect. | |
2760 | ||
2761 | So force this insn not to match in this (rare) case. */ | |
2762 | if (! in_dest && code == REG && GET_CODE (from) == REG | |
2763 | && REGNO (x) == REGNO (from)) | |
2764 | return gen_rtx (CLOBBER, GET_MODE (x), const0_rtx); | |
2765 | ||
2766 | /* If this is an object, we are done unless it is a MEM or LO_SUM, both | |
2767 | of which may contain things that can be combined. */ | |
2768 | if (code != MEM && code != LO_SUM && GET_RTX_CLASS (code) == 'o') | |
2769 | return x; | |
2770 | ||
2771 | /* It is possible to have a subexpression appear twice in the insn. | |
2772 | Suppose that FROM is a register that appears within TO. | |
2773 | Then, after that subexpression has been scanned once by `subst', | |
2774 | the second time it is scanned, TO may be found. If we were | |
2775 | to scan TO here, we would find FROM within it and create a | |
2776 | self-referent rtl structure which is completely wrong. */ | |
2777 | if (COMBINE_RTX_EQUAL_P (x, to)) | |
2778 | return to; | |
2779 | ||
2780 | len = GET_RTX_LENGTH (code); | |
2781 | fmt = GET_RTX_FORMAT (code); | |
2782 | ||
2783 | /* We don't need to process a SET_DEST that is a register, CC0, or PC, so | |
2784 | set up to skip this common case. All other cases where we want to | |
2785 | suppress replacing something inside a SET_SRC are handled via the | |
2786 | IN_DEST operand. */ | |
2787 | if (code == SET | |
2788 | && (GET_CODE (SET_DEST (x)) == REG | |
2789 | || GET_CODE (SET_DEST (x)) == CC0 | |
2790 | || GET_CODE (SET_DEST (x)) == PC)) | |
2791 | fmt = "ie"; | |
2792 | ||
2793 | /* Get the mode of operand 0 in case X is now a SIGN_EXTEND of a constant. */ | |
2794 | if (fmt[0] == 'e') | |
2795 | op0_mode = GET_MODE (XEXP (x, 0)); | |
2796 | ||
2797 | for (i = 0; i < len; i++) | |
2798 | { | |
2799 | if (fmt[i] == 'E') | |
2800 | { | |
2801 | register int j; | |
2802 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
2803 | { | |
230d793d RS |
2804 | if (COMBINE_RTX_EQUAL_P (XVECEXP (x, i, j), from)) |
2805 | { | |
2806 | new = (unique_copy && n_occurrences ? copy_rtx (to) : to); | |
2807 | n_occurrences++; | |
2808 | } | |
2809 | else | |
2810 | { | |
2811 | new = subst (XVECEXP (x, i, j), from, to, 0, unique_copy); | |
2812 | ||
2813 | /* If this substitution failed, this whole thing fails. */ | |
2814 | if (GET_CODE (new) == CLOBBER && XEXP (new, 0) == const0_rtx) | |
2815 | return new; | |
2816 | } | |
2817 | ||
2818 | SUBST (XVECEXP (x, i, j), new); | |
2819 | } | |
2820 | } | |
2821 | else if (fmt[i] == 'e') | |
2822 | { | |
230d793d RS |
2823 | if (COMBINE_RTX_EQUAL_P (XEXP (x, i), from)) |
2824 | { | |
42301240 RK |
2825 | /* In general, don't install a subreg involving two modes not |
2826 | tieable. It can worsen register allocation, and can even | |
2827 | make invalid reload insns, since the reg inside may need to | |
2828 | be copied from in the outside mode, and that may be invalid | |
2829 | if it is an fp reg copied in integer mode. | |
2830 | ||
2831 | We allow two exceptions to this: It is valid if it is inside | |
2832 | another SUBREG and the mode of that SUBREG and the mode of | |
2833 | the inside of TO is tieable and it is valid if X is a SET | |
2834 | that copies FROM to CC0. */ | |
2835 | if (GET_CODE (to) == SUBREG | |
2836 | && ! MODES_TIEABLE_P (GET_MODE (to), | |
2837 | GET_MODE (SUBREG_REG (to))) | |
2838 | && ! (code == SUBREG | |
8079805d RK |
2839 | && MODES_TIEABLE_P (GET_MODE (x), |
2840 | GET_MODE (SUBREG_REG (to)))) | |
42301240 RK |
2841 | #ifdef HAVE_cc0 |
2842 | && ! (code == SET && i == 1 && XEXP (x, 0) == cc0_rtx) | |
2843 | #endif | |
2844 | ) | |
2845 | return gen_rtx (CLOBBER, VOIDmode, const0_rtx); | |
2846 | ||
230d793d RS |
2847 | new = (unique_copy && n_occurrences ? copy_rtx (to) : to); |
2848 | n_occurrences++; | |
2849 | } | |
2850 | else | |
2851 | /* If we are in a SET_DEST, suppress most cases unless we | |
2852 | have gone inside a MEM, in which case we want to | |
2853 | simplify the address. We assume here that things that | |
2854 | are actually part of the destination have their inner | |
2855 | parts in the first expression. This is true for SUBREG, | |
2856 | STRICT_LOW_PART, and ZERO_EXTRACT, which are the only | |
2857 | things aside from REG and MEM that should appear in a | |
2858 | SET_DEST. */ | |
2859 | new = subst (XEXP (x, i), from, to, | |
2860 | (((in_dest | |
2861 | && (code == SUBREG || code == STRICT_LOW_PART | |
2862 | || code == ZERO_EXTRACT)) | |
2863 | || code == SET) | |
2864 | && i == 0), unique_copy); | |
2865 | ||
2866 | /* If we found that we will have to reject this combination, | |
2867 | indicate that by returning the CLOBBER ourselves, rather than | |
2868 | an expression containing it. This will speed things up as | |
2869 | well as prevent accidents where two CLOBBERs are considered | |
2870 | to be equal, thus producing an incorrect simplification. */ | |
2871 | ||
2872 | if (GET_CODE (new) == CLOBBER && XEXP (new, 0) == const0_rtx) | |
2873 | return new; | |
2874 | ||
2875 | SUBST (XEXP (x, i), new); | |
2876 | } | |
2877 | } | |
2878 | ||
8079805d RK |
2879 | /* Try to simplify X. If the simplification changed the code, it is likely |
2880 | that further simplification will help, so loop, but limit the number | |
2881 | of repetitions that will be performed. */ | |
2882 | ||
2883 | for (i = 0; i < 4; i++) | |
2884 | { | |
2885 | /* If X is sufficiently simple, don't bother trying to do anything | |
2886 | with it. */ | |
2887 | if (code != CONST_INT && code != REG && code != CLOBBER) | |
2888 | x = simplify_rtx (x, op0_mode, i == 3, in_dest); | |
d0ab8cd3 | 2889 | |
8079805d RK |
2890 | if (GET_CODE (x) == code) |
2891 | break; | |
d0ab8cd3 | 2892 | |
8079805d | 2893 | code = GET_CODE (x); |
eeb43d32 | 2894 | |
8079805d RK |
2895 | /* We no longer know the original mode of operand 0 since we |
2896 | have changed the form of X) */ | |
2897 | op0_mode = VOIDmode; | |
2898 | } | |
eeb43d32 | 2899 | |
8079805d RK |
2900 | return x; |
2901 | } | |
2902 | \f | |
2903 | /* Simplify X, a piece of RTL. We just operate on the expression at the | |
2904 | outer level; call `subst' to simplify recursively. Return the new | |
2905 | expression. | |
2906 | ||
2907 | OP0_MODE is the original mode of XEXP (x, 0); LAST is nonzero if this | |
2908 | will be the iteration even if an expression with a code different from | |
2909 | X is returned; IN_DEST is nonzero if we are inside a SET_DEST. */ | |
eeb43d32 | 2910 | |
8079805d RK |
2911 | static rtx |
2912 | simplify_rtx (x, op0_mode, last, in_dest) | |
2913 | rtx x; | |
2914 | enum machine_mode op0_mode; | |
2915 | int last; | |
2916 | int in_dest; | |
2917 | { | |
2918 | enum rtx_code code = GET_CODE (x); | |
2919 | enum machine_mode mode = GET_MODE (x); | |
2920 | rtx temp; | |
2921 | int i; | |
d0ab8cd3 | 2922 | |
230d793d RS |
2923 | /* If this is a commutative operation, put a constant last and a complex |
2924 | expression first. We don't need to do this for comparisons here. */ | |
2925 | if (GET_RTX_CLASS (code) == 'c' | |
2926 | && ((CONSTANT_P (XEXP (x, 0)) && GET_CODE (XEXP (x, 1)) != CONST_INT) | |
2927 | || (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'o' | |
2928 | && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o') | |
2929 | || (GET_CODE (XEXP (x, 0)) == SUBREG | |
2930 | && GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) == 'o' | |
2931 | && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o'))) | |
2932 | { | |
2933 | temp = XEXP (x, 0); | |
2934 | SUBST (XEXP (x, 0), XEXP (x, 1)); | |
2935 | SUBST (XEXP (x, 1), temp); | |
2936 | } | |
2937 | ||
22609cbf RK |
2938 | /* If this is a PLUS, MINUS, or MULT, and the first operand is the |
2939 | sign extension of a PLUS with a constant, reverse the order of the sign | |
2940 | extension and the addition. Note that this not the same as the original | |
2941 | code, but overflow is undefined for signed values. Also note that the | |
2942 | PLUS will have been partially moved "inside" the sign-extension, so that | |
2943 | the first operand of X will really look like: | |
2944 | (ashiftrt (plus (ashift A C4) C5) C4). | |
2945 | We convert this to | |
2946 | (plus (ashiftrt (ashift A C4) C2) C4) | |
2947 | and replace the first operand of X with that expression. Later parts | |
2948 | of this function may simplify the expression further. | |
2949 | ||
2950 | For example, if we start with (mult (sign_extend (plus A C1)) C2), | |
2951 | we swap the SIGN_EXTEND and PLUS. Later code will apply the | |
2952 | distributive law to produce (plus (mult (sign_extend X) C1) C3). | |
2953 | ||
2954 | We do this to simplify address expressions. */ | |
2955 | ||
2956 | if ((code == PLUS || code == MINUS || code == MULT) | |
2957 | && GET_CODE (XEXP (x, 0)) == ASHIFTRT | |
2958 | && GET_CODE (XEXP (XEXP (x, 0), 0)) == PLUS | |
2959 | && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == ASHIFT | |
2960 | && GET_CODE (XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1)) == CONST_INT | |
2961 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
2962 | && XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 1) == XEXP (XEXP (x, 0), 1) | |
2963 | && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == CONST_INT | |
2964 | && (temp = simplify_binary_operation (ASHIFTRT, mode, | |
2965 | XEXP (XEXP (XEXP (x, 0), 0), 1), | |
2966 | XEXP (XEXP (x, 0), 1))) != 0) | |
2967 | { | |
2968 | rtx new | |
2969 | = simplify_shift_const (NULL_RTX, ASHIFT, mode, | |
2970 | XEXP (XEXP (XEXP (XEXP (x, 0), 0), 0), 0), | |
2971 | INTVAL (XEXP (XEXP (x, 0), 1))); | |
2972 | ||
2973 | new = simplify_shift_const (NULL_RTX, ASHIFTRT, mode, new, | |
2974 | INTVAL (XEXP (XEXP (x, 0), 1))); | |
2975 | ||
2976 | SUBST (XEXP (x, 0), gen_binary (PLUS, mode, new, temp)); | |
2977 | } | |
2978 | ||
d0ab8cd3 RK |
2979 | /* If this is a simple operation applied to an IF_THEN_ELSE, try |
2980 | applying it to the arms of the IF_THEN_ELSE. This often simplifies | |
abe6e52f RK |
2981 | things. Check for cases where both arms are testing the same |
2982 | condition. | |
2983 | ||
2984 | Don't do anything if all operands are very simple. */ | |
2985 | ||
2986 | if (((GET_RTX_CLASS (code) == '2' || GET_RTX_CLASS (code) == 'c' | |
2987 | || GET_RTX_CLASS (code) == '<') | |
2988 | && ((GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) != 'o' | |
2989 | && ! (GET_CODE (XEXP (x, 0)) == SUBREG | |
2990 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) | |
2991 | == 'o'))) | |
2992 | || (GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) != 'o' | |
2993 | && ! (GET_CODE (XEXP (x, 1)) == SUBREG | |
2994 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 1)))) | |
2995 | == 'o'))))) | |
2996 | || (GET_RTX_CLASS (code) == '1' | |
2997 | && ((GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) != 'o' | |
2998 | && ! (GET_CODE (XEXP (x, 0)) == SUBREG | |
2999 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (XEXP (x, 0)))) | |
3000 | == 'o')))))) | |
d0ab8cd3 | 3001 | { |
abe6e52f RK |
3002 | rtx cond, true, false; |
3003 | ||
3004 | cond = if_then_else_cond (x, &true, &false); | |
3005 | if (cond != 0) | |
3006 | { | |
3007 | rtx cop1 = const0_rtx; | |
3008 | enum rtx_code cond_code = simplify_comparison (NE, &cond, &cop1); | |
3009 | ||
9210df58 RK |
3010 | /* Simplify the alternative arms; this may collapse the true and |
3011 | false arms to store-flag values. */ | |
3012 | true = subst (true, pc_rtx, pc_rtx, 0, 0); | |
3013 | false = subst (false, pc_rtx, pc_rtx, 0, 0); | |
3014 | ||
3015 | /* Restarting if we generate a store-flag expression will cause | |
3016 | us to loop. Just drop through in this case. */ | |
3017 | ||
abe6e52f RK |
3018 | /* If the result values are STORE_FLAG_VALUE and zero, we can |
3019 | just make the comparison operation. */ | |
3020 | if (true == const_true_rtx && false == const0_rtx) | |
3021 | x = gen_binary (cond_code, mode, cond, cop1); | |
3022 | else if (true == const0_rtx && false == const_true_rtx) | |
3023 | x = gen_binary (reverse_condition (cond_code), mode, cond, cop1); | |
3024 | ||
3025 | /* Likewise, we can make the negate of a comparison operation | |
3026 | if the result values are - STORE_FLAG_VALUE and zero. */ | |
3027 | else if (GET_CODE (true) == CONST_INT | |
3028 | && INTVAL (true) == - STORE_FLAG_VALUE | |
3029 | && false == const0_rtx) | |
0c1c8ea6 | 3030 | x = gen_unary (NEG, mode, mode, |
abe6e52f RK |
3031 | gen_binary (cond_code, mode, cond, cop1)); |
3032 | else if (GET_CODE (false) == CONST_INT | |
3033 | && INTVAL (false) == - STORE_FLAG_VALUE | |
3034 | && true == const0_rtx) | |
0c1c8ea6 | 3035 | x = gen_unary (NEG, mode, mode, |
abe6e52f RK |
3036 | gen_binary (reverse_condition (cond_code), |
3037 | mode, cond, cop1)); | |
3038 | else | |
8079805d RK |
3039 | return gen_rtx (IF_THEN_ELSE, mode, |
3040 | gen_binary (cond_code, VOIDmode, cond, cop1), | |
3041 | true, false); | |
5109d49f | 3042 | |
9210df58 RK |
3043 | code = GET_CODE (x); |
3044 | op0_mode = VOIDmode; | |
abe6e52f | 3045 | } |
d0ab8cd3 RK |
3046 | } |
3047 | ||
230d793d RS |
3048 | /* Try to fold this expression in case we have constants that weren't |
3049 | present before. */ | |
3050 | temp = 0; | |
3051 | switch (GET_RTX_CLASS (code)) | |
3052 | { | |
3053 | case '1': | |
3054 | temp = simplify_unary_operation (code, mode, XEXP (x, 0), op0_mode); | |
3055 | break; | |
3056 | case '<': | |
3057 | temp = simplify_relational_operation (code, op0_mode, | |
3058 | XEXP (x, 0), XEXP (x, 1)); | |
77fa0940 RK |
3059 | #ifdef FLOAT_STORE_FLAG_VALUE |
3060 | if (temp != 0 && GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT) | |
3061 | temp = ((temp == const0_rtx) ? CONST0_RTX (GET_MODE (x)) | |
3062 | : immed_real_const_1 (FLOAT_STORE_FLAG_VALUE, GET_MODE (x))); | |
3063 | #endif | |
230d793d RS |
3064 | break; |
3065 | case 'c': | |
3066 | case '2': | |
3067 | temp = simplify_binary_operation (code, mode, XEXP (x, 0), XEXP (x, 1)); | |
3068 | break; | |
3069 | case 'b': | |
3070 | case '3': | |
3071 | temp = simplify_ternary_operation (code, mode, op0_mode, XEXP (x, 0), | |
3072 | XEXP (x, 1), XEXP (x, 2)); | |
3073 | break; | |
3074 | } | |
3075 | ||
3076 | if (temp) | |
d0ab8cd3 | 3077 | x = temp, code = GET_CODE (temp); |
230d793d | 3078 | |
230d793d | 3079 | /* First see if we can apply the inverse distributive law. */ |
224eeff2 RK |
3080 | if (code == PLUS || code == MINUS |
3081 | || code == AND || code == IOR || code == XOR) | |
230d793d RS |
3082 | { |
3083 | x = apply_distributive_law (x); | |
3084 | code = GET_CODE (x); | |
3085 | } | |
3086 | ||
3087 | /* If CODE is an associative operation not otherwise handled, see if we | |
3088 | can associate some operands. This can win if they are constants or | |
3089 | if they are logically related (i.e. (a & b) & a. */ | |
3090 | if ((code == PLUS || code == MINUS | |
3091 | || code == MULT || code == AND || code == IOR || code == XOR | |
3092 | || code == DIV || code == UDIV | |
3093 | || code == SMAX || code == SMIN || code == UMAX || code == UMIN) | |
3ad2180a | 3094 | && INTEGRAL_MODE_P (mode)) |
230d793d RS |
3095 | { |
3096 | if (GET_CODE (XEXP (x, 0)) == code) | |
3097 | { | |
3098 | rtx other = XEXP (XEXP (x, 0), 0); | |
3099 | rtx inner_op0 = XEXP (XEXP (x, 0), 1); | |
3100 | rtx inner_op1 = XEXP (x, 1); | |
3101 | rtx inner; | |
3102 | ||
3103 | /* Make sure we pass the constant operand if any as the second | |
3104 | one if this is a commutative operation. */ | |
3105 | if (CONSTANT_P (inner_op0) && GET_RTX_CLASS (code) == 'c') | |
3106 | { | |
3107 | rtx tem = inner_op0; | |
3108 | inner_op0 = inner_op1; | |
3109 | inner_op1 = tem; | |
3110 | } | |
3111 | inner = simplify_binary_operation (code == MINUS ? PLUS | |
3112 | : code == DIV ? MULT | |
3113 | : code == UDIV ? MULT | |
3114 | : code, | |
3115 | mode, inner_op0, inner_op1); | |
3116 | ||
3117 | /* For commutative operations, try the other pair if that one | |
3118 | didn't simplify. */ | |
3119 | if (inner == 0 && GET_RTX_CLASS (code) == 'c') | |
3120 | { | |
3121 | other = XEXP (XEXP (x, 0), 1); | |
3122 | inner = simplify_binary_operation (code, mode, | |
3123 | XEXP (XEXP (x, 0), 0), | |
3124 | XEXP (x, 1)); | |
3125 | } | |
3126 | ||
3127 | if (inner) | |
8079805d | 3128 | return gen_binary (code, mode, other, inner); |
230d793d RS |
3129 | } |
3130 | } | |
3131 | ||
3132 | /* A little bit of algebraic simplification here. */ | |
3133 | switch (code) | |
3134 | { | |
3135 | case MEM: | |
3136 | /* Ensure that our address has any ASHIFTs converted to MULT in case | |
3137 | address-recognizing predicates are called later. */ | |
3138 | temp = make_compound_operation (XEXP (x, 0), MEM); | |
3139 | SUBST (XEXP (x, 0), temp); | |
3140 | break; | |
3141 | ||
3142 | case SUBREG: | |
3143 | /* (subreg:A (mem:B X) N) becomes a modified MEM unless the SUBREG | |
3144 | is paradoxical. If we can't do that safely, then it becomes | |
3145 | something nonsensical so that this combination won't take place. */ | |
3146 | ||
3147 | if (GET_CODE (SUBREG_REG (x)) == MEM | |
3148 | && (GET_MODE_SIZE (mode) | |
3149 | <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))) | |
3150 | { | |
3151 | rtx inner = SUBREG_REG (x); | |
3152 | int endian_offset = 0; | |
3153 | /* Don't change the mode of the MEM | |
3154 | if that would change the meaning of the address. */ | |
3155 | if (MEM_VOLATILE_P (SUBREG_REG (x)) | |
3156 | || mode_dependent_address_p (XEXP (inner, 0))) | |
3157 | return gen_rtx (CLOBBER, mode, const0_rtx); | |
3158 | ||
3159 | #if BYTES_BIG_ENDIAN | |
3160 | if (GET_MODE_SIZE (mode) < UNITS_PER_WORD) | |
3161 | endian_offset += UNITS_PER_WORD - GET_MODE_SIZE (mode); | |
3162 | if (GET_MODE_SIZE (GET_MODE (inner)) < UNITS_PER_WORD) | |
3163 | endian_offset -= UNITS_PER_WORD - GET_MODE_SIZE (GET_MODE (inner)); | |
3164 | #endif | |
3165 | /* Note if the plus_constant doesn't make a valid address | |
3166 | then this combination won't be accepted. */ | |
3167 | x = gen_rtx (MEM, mode, | |
3168 | plus_constant (XEXP (inner, 0), | |
3169 | (SUBREG_WORD (x) * UNITS_PER_WORD | |
3170 | + endian_offset))); | |
3171 | MEM_VOLATILE_P (x) = MEM_VOLATILE_P (inner); | |
3172 | RTX_UNCHANGING_P (x) = RTX_UNCHANGING_P (inner); | |
3173 | MEM_IN_STRUCT_P (x) = MEM_IN_STRUCT_P (inner); | |
3174 | return x; | |
3175 | } | |
3176 | ||
3177 | /* If we are in a SET_DEST, these other cases can't apply. */ | |
3178 | if (in_dest) | |
3179 | return x; | |
3180 | ||
3181 | /* Changing mode twice with SUBREG => just change it once, | |
3182 | or not at all if changing back to starting mode. */ | |
3183 | if (GET_CODE (SUBREG_REG (x)) == SUBREG) | |
3184 | { | |
3185 | if (mode == GET_MODE (SUBREG_REG (SUBREG_REG (x))) | |
3186 | && SUBREG_WORD (x) == 0 && SUBREG_WORD (SUBREG_REG (x)) == 0) | |
3187 | return SUBREG_REG (SUBREG_REG (x)); | |
3188 | ||
3189 | SUBST_INT (SUBREG_WORD (x), | |
3190 | SUBREG_WORD (x) + SUBREG_WORD (SUBREG_REG (x))); | |
3191 | SUBST (SUBREG_REG (x), SUBREG_REG (SUBREG_REG (x))); | |
3192 | } | |
3193 | ||
3194 | /* SUBREG of a hard register => just change the register number | |
3195 | and/or mode. If the hard register is not valid in that mode, | |
26ecfc76 RK |
3196 | suppress this combination. If the hard register is the stack, |
3197 | frame, or argument pointer, leave this as a SUBREG. */ | |
230d793d RS |
3198 | |
3199 | if (GET_CODE (SUBREG_REG (x)) == REG | |
26ecfc76 RK |
3200 | && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER |
3201 | && REGNO (SUBREG_REG (x)) != FRAME_POINTER_REGNUM | |
6d7096b0 DE |
3202 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
3203 | && REGNO (SUBREG_REG (x)) != HARD_FRAME_POINTER_REGNUM | |
3204 | #endif | |
26ecfc76 RK |
3205 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
3206 | && REGNO (SUBREG_REG (x)) != ARG_POINTER_REGNUM | |
3207 | #endif | |
3208 | && REGNO (SUBREG_REG (x)) != STACK_POINTER_REGNUM) | |
230d793d RS |
3209 | { |
3210 | if (HARD_REGNO_MODE_OK (REGNO (SUBREG_REG (x)) + SUBREG_WORD (x), | |
3211 | mode)) | |
3212 | return gen_rtx (REG, mode, | |
3213 | REGNO (SUBREG_REG (x)) + SUBREG_WORD (x)); | |
3214 | else | |
3215 | return gen_rtx (CLOBBER, mode, const0_rtx); | |
3216 | } | |
3217 | ||
3218 | /* For a constant, try to pick up the part we want. Handle a full | |
a4bde0b1 RK |
3219 | word and low-order part. Only do this if we are narrowing |
3220 | the constant; if it is being widened, we have no idea what | |
3221 | the extra bits will have been set to. */ | |
230d793d RS |
3222 | |
3223 | if (CONSTANT_P (SUBREG_REG (x)) && op0_mode != VOIDmode | |
3224 | && GET_MODE_SIZE (mode) == UNITS_PER_WORD | |
a4bde0b1 | 3225 | && GET_MODE_SIZE (op0_mode) < UNITS_PER_WORD |
230d793d RS |
3226 | && GET_MODE_CLASS (mode) == MODE_INT) |
3227 | { | |
3228 | temp = operand_subword (SUBREG_REG (x), SUBREG_WORD (x), | |
5f4f0e22 | 3229 | 0, op0_mode); |
230d793d RS |
3230 | if (temp) |
3231 | return temp; | |
3232 | } | |
3233 | ||
19808e22 RS |
3234 | /* If we want a subreg of a constant, at offset 0, |
3235 | take the low bits. On a little-endian machine, that's | |
3236 | always valid. On a big-endian machine, it's valid | |
3237 | only if the constant's mode fits in one word. */ | |
a4bde0b1 | 3238 | if (CONSTANT_P (SUBREG_REG (x)) && subreg_lowpart_p (x) |
19808e22 RS |
3239 | && GET_MODE_SIZE (mode) < GET_MODE_SIZE (op0_mode) |
3240 | #if WORDS_BIG_ENDIAN | |
097e45d1 | 3241 | && GET_MODE_BITSIZE (op0_mode) <= BITS_PER_WORD |
19808e22 RS |
3242 | #endif |
3243 | ) | |
230d793d RS |
3244 | return gen_lowpart_for_combine (mode, SUBREG_REG (x)); |
3245 | ||
b65c1b5b RK |
3246 | /* A paradoxical SUBREG of a VOIDmode constant is the same constant, |
3247 | since we are saying that the high bits don't matter. */ | |
3248 | if (CONSTANT_P (SUBREG_REG (x)) && GET_MODE (SUBREG_REG (x)) == VOIDmode | |
3249 | && GET_MODE_SIZE (mode) > GET_MODE_SIZE (op0_mode)) | |
3250 | return SUBREG_REG (x); | |
3251 | ||
87e3e0c1 RK |
3252 | /* Note that we cannot do any narrowing for non-constants since |
3253 | we might have been counting on using the fact that some bits were | |
3254 | zero. We now do this in the SET. */ | |
3255 | ||
230d793d RS |
3256 | break; |
3257 | ||
3258 | case NOT: | |
3259 | /* (not (plus X -1)) can become (neg X). */ | |
3260 | if (GET_CODE (XEXP (x, 0)) == PLUS | |
3261 | && XEXP (XEXP (x, 0), 1) == constm1_rtx) | |
8079805d | 3262 | return gen_rtx_combine (NEG, mode, XEXP (XEXP (x, 0), 0)); |
230d793d RS |
3263 | |
3264 | /* Similarly, (not (neg X)) is (plus X -1). */ | |
3265 | if (GET_CODE (XEXP (x, 0)) == NEG) | |
8079805d RK |
3266 | return gen_rtx_combine (PLUS, mode, XEXP (XEXP (x, 0), 0), |
3267 | constm1_rtx); | |
230d793d | 3268 | |
d0ab8cd3 RK |
3269 | /* (not (xor X C)) for C constant is (xor X D) with D = ~ C. */ |
3270 | if (GET_CODE (XEXP (x, 0)) == XOR | |
3271 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
3272 | && (temp = simplify_unary_operation (NOT, mode, | |
3273 | XEXP (XEXP (x, 0), 1), | |
3274 | mode)) != 0) | |
787745f5 | 3275 | return gen_binary (XOR, mode, XEXP (XEXP (x, 0), 0), temp); |
d0ab8cd3 | 3276 | |
230d793d RS |
3277 | /* (not (ashift 1 X)) is (rotate ~1 X). We used to do this for operands |
3278 | other than 1, but that is not valid. We could do a similar | |
3279 | simplification for (not (lshiftrt C X)) where C is just the sign bit, | |
3280 | but this doesn't seem common enough to bother with. */ | |
3281 | if (GET_CODE (XEXP (x, 0)) == ASHIFT | |
3282 | && XEXP (XEXP (x, 0), 0) == const1_rtx) | |
0c1c8ea6 | 3283 | return gen_rtx (ROTATE, mode, gen_unary (NOT, mode, mode, const1_rtx), |
8079805d | 3284 | XEXP (XEXP (x, 0), 1)); |
230d793d RS |
3285 | |
3286 | if (GET_CODE (XEXP (x, 0)) == SUBREG | |
3287 | && subreg_lowpart_p (XEXP (x, 0)) | |
3288 | && (GET_MODE_SIZE (GET_MODE (XEXP (x, 0))) | |
3289 | < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (x, 0))))) | |
3290 | && GET_CODE (SUBREG_REG (XEXP (x, 0))) == ASHIFT | |
3291 | && XEXP (SUBREG_REG (XEXP (x, 0)), 0) == const1_rtx) | |
3292 | { | |
3293 | enum machine_mode inner_mode = GET_MODE (SUBREG_REG (XEXP (x, 0))); | |
3294 | ||
3295 | x = gen_rtx (ROTATE, inner_mode, | |
0c1c8ea6 | 3296 | gen_unary (NOT, inner_mode, inner_mode, const1_rtx), |
230d793d | 3297 | XEXP (SUBREG_REG (XEXP (x, 0)), 1)); |
8079805d | 3298 | return gen_lowpart_for_combine (mode, x); |
230d793d RS |
3299 | } |
3300 | ||
3301 | #if STORE_FLAG_VALUE == -1 | |
3302 | /* (not (comparison foo bar)) can be done by reversing the comparison | |
3303 | code if valid. */ | |
3304 | if (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' | |
3305 | && reversible_comparison_p (XEXP (x, 0))) | |
3306 | return gen_rtx_combine (reverse_condition (GET_CODE (XEXP (x, 0))), | |
3307 | mode, XEXP (XEXP (x, 0), 0), | |
3308 | XEXP (XEXP (x, 0), 1)); | |
500c518b RK |
3309 | |
3310 | /* (ashiftrt foo C) where C is the number of bits in FOO minus 1 | |
3311 | is (lt foo (const_int 0)), so we can perform the above | |
3312 | simplification. */ | |
3313 | ||
3314 | if (XEXP (x, 1) == const1_rtx | |
3315 | && GET_CODE (XEXP (x, 0)) == ASHIFTRT | |
3316 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
3317 | && INTVAL (XEXP (XEXP (x, 0), 1)) == GET_MODE_BITSIZE (mode) - 1) | |
3318 | return gen_rtx_combine (GE, mode, XEXP (XEXP (x, 0), 0), const0_rtx); | |
230d793d RS |
3319 | #endif |
3320 | ||
3321 | /* Apply De Morgan's laws to reduce number of patterns for machines | |
3322 | with negating logical insns (and-not, nand, etc.). If result has | |
3323 | only one NOT, put it first, since that is how the patterns are | |
3324 | coded. */ | |
3325 | ||
3326 | if (GET_CODE (XEXP (x, 0)) == IOR || GET_CODE (XEXP (x, 0)) == AND) | |
3327 | { | |
3328 | rtx in1 = XEXP (XEXP (x, 0), 0), in2 = XEXP (XEXP (x, 0), 1); | |
3329 | ||
3330 | if (GET_CODE (in1) == NOT) | |
3331 | in1 = XEXP (in1, 0); | |
3332 | else | |
3333 | in1 = gen_rtx_combine (NOT, GET_MODE (in1), in1); | |
3334 | ||
3335 | if (GET_CODE (in2) == NOT) | |
3336 | in2 = XEXP (in2, 0); | |
3337 | else if (GET_CODE (in2) == CONST_INT | |
5f4f0e22 CH |
3338 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) |
3339 | in2 = GEN_INT (GET_MODE_MASK (mode) & ~ INTVAL (in2)); | |
230d793d RS |
3340 | else |
3341 | in2 = gen_rtx_combine (NOT, GET_MODE (in2), in2); | |
3342 | ||
3343 | if (GET_CODE (in2) == NOT) | |
3344 | { | |
3345 | rtx tem = in2; | |
3346 | in2 = in1; in1 = tem; | |
3347 | } | |
3348 | ||
8079805d RK |
3349 | return gen_rtx_combine (GET_CODE (XEXP (x, 0)) == IOR ? AND : IOR, |
3350 | mode, in1, in2); | |
230d793d RS |
3351 | } |
3352 | break; | |
3353 | ||
3354 | case NEG: | |
3355 | /* (neg (plus X 1)) can become (not X). */ | |
3356 | if (GET_CODE (XEXP (x, 0)) == PLUS | |
3357 | && XEXP (XEXP (x, 0), 1) == const1_rtx) | |
8079805d | 3358 | return gen_rtx_combine (NOT, mode, XEXP (XEXP (x, 0), 0)); |
230d793d RS |
3359 | |
3360 | /* Similarly, (neg (not X)) is (plus X 1). */ | |
3361 | if (GET_CODE (XEXP (x, 0)) == NOT) | |
8079805d | 3362 | return plus_constant (XEXP (XEXP (x, 0), 0), 1); |
230d793d | 3363 | |
230d793d RS |
3364 | /* (neg (minus X Y)) can become (minus Y X). */ |
3365 | if (GET_CODE (XEXP (x, 0)) == MINUS | |
3ad2180a | 3366 | && (! FLOAT_MODE_P (mode) |
230d793d | 3367 | /* x-y != -(y-x) with IEEE floating point. */ |
7e2a0d8e RK |
3368 | || TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT |
3369 | || flag_fast_math)) | |
8079805d RK |
3370 | return gen_binary (MINUS, mode, XEXP (XEXP (x, 0), 1), |
3371 | XEXP (XEXP (x, 0), 0)); | |
230d793d | 3372 | |
d0ab8cd3 RK |
3373 | /* (neg (xor A 1)) is (plus A -1) if A is known to be either 0 or 1. */ |
3374 | if (GET_CODE (XEXP (x, 0)) == XOR && XEXP (XEXP (x, 0), 1) == const1_rtx | |
951553af | 3375 | && nonzero_bits (XEXP (XEXP (x, 0), 0), mode) == 1) |
8079805d | 3376 | return gen_binary (PLUS, mode, XEXP (XEXP (x, 0), 0), constm1_rtx); |
d0ab8cd3 | 3377 | |
230d793d RS |
3378 | /* NEG commutes with ASHIFT since it is multiplication. Only do this |
3379 | if we can then eliminate the NEG (e.g., | |
3380 | if the operand is a constant). */ | |
3381 | ||
3382 | if (GET_CODE (XEXP (x, 0)) == ASHIFT) | |
3383 | { | |
3384 | temp = simplify_unary_operation (NEG, mode, | |
3385 | XEXP (XEXP (x, 0), 0), mode); | |
3386 | if (temp) | |
3387 | { | |
3388 | SUBST (XEXP (XEXP (x, 0), 0), temp); | |
3389 | return XEXP (x, 0); | |
3390 | } | |
3391 | } | |
3392 | ||
3393 | temp = expand_compound_operation (XEXP (x, 0)); | |
3394 | ||
3395 | /* For C equal to the width of MODE minus 1, (neg (ashiftrt X C)) can be | |
3396 | replaced by (lshiftrt X C). This will convert | |
3397 | (neg (sign_extract X 1 Y)) to (zero_extract X 1 Y). */ | |
3398 | ||
3399 | if (GET_CODE (temp) == ASHIFTRT | |
3400 | && GET_CODE (XEXP (temp, 1)) == CONST_INT | |
3401 | && INTVAL (XEXP (temp, 1)) == GET_MODE_BITSIZE (mode) - 1) | |
8079805d RK |
3402 | return simplify_shift_const (temp, LSHIFTRT, mode, XEXP (temp, 0), |
3403 | INTVAL (XEXP (temp, 1))); | |
230d793d | 3404 | |
951553af | 3405 | /* If X has only a single bit that might be nonzero, say, bit I, convert |
230d793d RS |
3406 | (neg X) to (ashiftrt (ashift X C-I) C-I) where C is the bitsize of |
3407 | MODE minus 1. This will convert (neg (zero_extract X 1 Y)) to | |
3408 | (sign_extract X 1 Y). But only do this if TEMP isn't a register | |
3409 | or a SUBREG of one since we'd be making the expression more | |
3410 | complex if it was just a register. */ | |
3411 | ||
3412 | if (GET_CODE (temp) != REG | |
3413 | && ! (GET_CODE (temp) == SUBREG | |
3414 | && GET_CODE (SUBREG_REG (temp)) == REG) | |
951553af | 3415 | && (i = exact_log2 (nonzero_bits (temp, mode))) >= 0) |
230d793d RS |
3416 | { |
3417 | rtx temp1 = simplify_shift_const | |
5f4f0e22 CH |
3418 | (NULL_RTX, ASHIFTRT, mode, |
3419 | simplify_shift_const (NULL_RTX, ASHIFT, mode, temp, | |
230d793d RS |
3420 | GET_MODE_BITSIZE (mode) - 1 - i), |
3421 | GET_MODE_BITSIZE (mode) - 1 - i); | |
3422 | ||
3423 | /* If all we did was surround TEMP with the two shifts, we | |
3424 | haven't improved anything, so don't use it. Otherwise, | |
3425 | we are better off with TEMP1. */ | |
3426 | if (GET_CODE (temp1) != ASHIFTRT | |
3427 | || GET_CODE (XEXP (temp1, 0)) != ASHIFT | |
3428 | || XEXP (XEXP (temp1, 0), 0) != temp) | |
8079805d | 3429 | return temp1; |
230d793d RS |
3430 | } |
3431 | break; | |
3432 | ||
3433 | case FLOAT_TRUNCATE: | |
3434 | /* (float_truncate:SF (float_extend:DF foo:SF)) = foo:SF. */ | |
3435 | if (GET_CODE (XEXP (x, 0)) == FLOAT_EXTEND | |
3436 | && GET_MODE (XEXP (XEXP (x, 0), 0)) == mode) | |
3437 | return XEXP (XEXP (x, 0), 0); | |
4635f748 RK |
3438 | |
3439 | /* (float_truncate:SF (OP:DF (float_extend:DF foo:sf))) is | |
3440 | (OP:SF foo:SF) if OP is NEG or ABS. */ | |
3441 | if ((GET_CODE (XEXP (x, 0)) == ABS | |
3442 | || GET_CODE (XEXP (x, 0)) == NEG) | |
3443 | && GET_CODE (XEXP (XEXP (x, 0), 0)) == FLOAT_EXTEND | |
3444 | && GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == mode) | |
0c1c8ea6 RK |
3445 | return gen_unary (GET_CODE (XEXP (x, 0)), mode, mode, |
3446 | XEXP (XEXP (XEXP (x, 0), 0), 0)); | |
1d12df72 RK |
3447 | |
3448 | /* (float_truncate:SF (subreg:DF (float_truncate:SF X) 0)) | |
3449 | is (float_truncate:SF x). */ | |
3450 | if (GET_CODE (XEXP (x, 0)) == SUBREG | |
3451 | && subreg_lowpart_p (XEXP (x, 0)) | |
3452 | && GET_CODE (SUBREG_REG (XEXP (x, 0))) == FLOAT_TRUNCATE) | |
3453 | return SUBREG_REG (XEXP (x, 0)); | |
230d793d RS |
3454 | break; |
3455 | ||
3456 | #ifdef HAVE_cc0 | |
3457 | case COMPARE: | |
3458 | /* Convert (compare FOO (const_int 0)) to FOO unless we aren't | |
3459 | using cc0, in which case we want to leave it as a COMPARE | |
3460 | so we can distinguish it from a register-register-copy. */ | |
3461 | if (XEXP (x, 1) == const0_rtx) | |
3462 | return XEXP (x, 0); | |
3463 | ||
3464 | /* In IEEE floating point, x-0 is not the same as x. */ | |
3465 | if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT | |
7e2a0d8e RK |
3466 | || ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0))) |
3467 | || flag_fast_math) | |
230d793d RS |
3468 | && XEXP (x, 1) == CONST0_RTX (GET_MODE (XEXP (x, 0)))) |
3469 | return XEXP (x, 0); | |
3470 | break; | |
3471 | #endif | |
3472 | ||
3473 | case CONST: | |
3474 | /* (const (const X)) can become (const X). Do it this way rather than | |
3475 | returning the inner CONST since CONST can be shared with a | |
3476 | REG_EQUAL note. */ | |
3477 | if (GET_CODE (XEXP (x, 0)) == CONST) | |
3478 | SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); | |
3479 | break; | |
3480 | ||
3481 | #ifdef HAVE_lo_sum | |
3482 | case LO_SUM: | |
3483 | /* Convert (lo_sum (high FOO) FOO) to FOO. This is necessary so we | |
3484 | can add in an offset. find_split_point will split this address up | |
3485 | again if it doesn't match. */ | |
3486 | if (GET_CODE (XEXP (x, 0)) == HIGH | |
3487 | && rtx_equal_p (XEXP (XEXP (x, 0), 0), XEXP (x, 1))) | |
3488 | return XEXP (x, 1); | |
3489 | break; | |
3490 | #endif | |
3491 | ||
3492 | case PLUS: | |
3493 | /* If we have (plus (plus (A const) B)), associate it so that CONST is | |
3494 | outermost. That's because that's the way indexed addresses are | |
3495 | supposed to appear. This code used to check many more cases, but | |
3496 | they are now checked elsewhere. */ | |
3497 | if (GET_CODE (XEXP (x, 0)) == PLUS | |
3498 | && CONSTANT_ADDRESS_P (XEXP (XEXP (x, 0), 1))) | |
3499 | return gen_binary (PLUS, mode, | |
3500 | gen_binary (PLUS, mode, XEXP (XEXP (x, 0), 0), | |
3501 | XEXP (x, 1)), | |
3502 | XEXP (XEXP (x, 0), 1)); | |
3503 | ||
3504 | /* (plus (xor (and <foo> (const_int pow2 - 1)) <c>) <-c>) | |
3505 | when c is (const_int (pow2 + 1) / 2) is a sign extension of a | |
3506 | bit-field and can be replaced by either a sign_extend or a | |
3507 | sign_extract. The `and' may be a zero_extend. */ | |
3508 | if (GET_CODE (XEXP (x, 0)) == XOR | |
3509 | && GET_CODE (XEXP (x, 1)) == CONST_INT | |
3510 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
3511 | && INTVAL (XEXP (x, 1)) == - INTVAL (XEXP (XEXP (x, 0), 1)) | |
3512 | && (i = exact_log2 (INTVAL (XEXP (XEXP (x, 0), 1)))) >= 0 | |
5f4f0e22 | 3513 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
230d793d RS |
3514 | && ((GET_CODE (XEXP (XEXP (x, 0), 0)) == AND |
3515 | && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 1)) == CONST_INT | |
3516 | && (INTVAL (XEXP (XEXP (XEXP (x, 0), 0), 1)) | |
5f4f0e22 | 3517 | == ((HOST_WIDE_INT) 1 << (i + 1)) - 1)) |
230d793d RS |
3518 | || (GET_CODE (XEXP (XEXP (x, 0), 0)) == ZERO_EXTEND |
3519 | && (GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0))) | |
3520 | == i + 1)))) | |
8079805d RK |
3521 | return simplify_shift_const |
3522 | (NULL_RTX, ASHIFTRT, mode, | |
3523 | simplify_shift_const (NULL_RTX, ASHIFT, mode, | |
3524 | XEXP (XEXP (XEXP (x, 0), 0), 0), | |
3525 | GET_MODE_BITSIZE (mode) - (i + 1)), | |
3526 | GET_MODE_BITSIZE (mode) - (i + 1)); | |
230d793d | 3527 | |
bc0776c6 RK |
3528 | /* (plus (comparison A B) C) can become (neg (rev-comp A B)) if |
3529 | C is 1 and STORE_FLAG_VALUE is -1 or if C is -1 and STORE_FLAG_VALUE | |
3530 | is 1. This produces better code than the alternative immediately | |
3531 | below. */ | |
3532 | if (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == '<' | |
3533 | && reversible_comparison_p (XEXP (x, 0)) | |
3534 | && ((STORE_FLAG_VALUE == -1 && XEXP (x, 1) == const1_rtx) | |
3535 | || (STORE_FLAG_VALUE == 1 && XEXP (x, 1) == constm1_rtx))) | |
8079805d | 3536 | return |
0c1c8ea6 | 3537 | gen_unary (NEG, mode, mode, |
8079805d RK |
3538 | gen_binary (reverse_condition (GET_CODE (XEXP (x, 0))), |
3539 | mode, XEXP (XEXP (x, 0), 0), | |
3540 | XEXP (XEXP (x, 0), 1))); | |
bc0776c6 RK |
3541 | |
3542 | /* If only the low-order bit of X is possibly nonzero, (plus x -1) | |
230d793d RS |
3543 | can become (ashiftrt (ashift (xor x 1) C) C) where C is |
3544 | the bitsize of the mode - 1. This allows simplification of | |
3545 | "a = (b & 8) == 0;" */ | |
3546 | if (XEXP (x, 1) == constm1_rtx | |
3547 | && GET_CODE (XEXP (x, 0)) != REG | |
3548 | && ! (GET_CODE (XEXP (x,0)) == SUBREG | |
3549 | && GET_CODE (SUBREG_REG (XEXP (x, 0))) == REG) | |
951553af | 3550 | && nonzero_bits (XEXP (x, 0), mode) == 1) |
8079805d RK |
3551 | return simplify_shift_const (NULL_RTX, ASHIFTRT, mode, |
3552 | simplify_shift_const (NULL_RTX, ASHIFT, mode, | |
3553 | gen_rtx_combine (XOR, mode, | |
3554 | XEXP (x, 0), const1_rtx), | |
3555 | GET_MODE_BITSIZE (mode) - 1), | |
3556 | GET_MODE_BITSIZE (mode) - 1); | |
02f4ada4 RK |
3557 | |
3558 | /* If we are adding two things that have no bits in common, convert | |
3559 | the addition into an IOR. This will often be further simplified, | |
3560 | for example in cases like ((a & 1) + (a & 2)), which can | |
3561 | become a & 3. */ | |
3562 | ||
ac49a949 | 3563 | if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
951553af RK |
3564 | && (nonzero_bits (XEXP (x, 0), mode) |
3565 | & nonzero_bits (XEXP (x, 1), mode)) == 0) | |
8079805d | 3566 | return gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1)); |
230d793d RS |
3567 | break; |
3568 | ||
3569 | case MINUS: | |
5109d49f RK |
3570 | #if STORE_FLAG_VALUE == 1 |
3571 | /* (minus 1 (comparison foo bar)) can be done by reversing the comparison | |
3572 | code if valid. */ | |
3573 | if (XEXP (x, 0) == const1_rtx | |
3574 | && GET_RTX_CLASS (GET_CODE (XEXP (x, 1))) == '<' | |
3575 | && reversible_comparison_p (XEXP (x, 1))) | |
3576 | return gen_binary (reverse_condition (GET_CODE (XEXP (x, 1))), | |
3577 | mode, XEXP (XEXP (x, 1), 0), | |
3578 | XEXP (XEXP (x, 1), 1)); | |
3579 | #endif | |
3580 | ||
230d793d RS |
3581 | /* (minus <foo> (and <foo> (const_int -pow2))) becomes |
3582 | (and <foo> (const_int pow2-1)) */ | |
3583 | if (GET_CODE (XEXP (x, 1)) == AND | |
3584 | && GET_CODE (XEXP (XEXP (x, 1), 1)) == CONST_INT | |
3585 | && exact_log2 (- INTVAL (XEXP (XEXP (x, 1), 1))) >= 0 | |
3586 | && rtx_equal_p (XEXP (XEXP (x, 1), 0), XEXP (x, 0))) | |
8079805d RK |
3587 | return simplify_and_const_int (NULL_RTX, mode, XEXP (x, 0), |
3588 | - INTVAL (XEXP (XEXP (x, 1), 1)) - 1); | |
7bef8680 RK |
3589 | |
3590 | /* Canonicalize (minus A (plus B C)) to (minus (minus A B) C) for | |
3591 | integers. */ | |
3592 | if (GET_CODE (XEXP (x, 1)) == PLUS && INTEGRAL_MODE_P (mode)) | |
8079805d RK |
3593 | return gen_binary (MINUS, mode, |
3594 | gen_binary (MINUS, mode, XEXP (x, 0), | |
3595 | XEXP (XEXP (x, 1), 0)), | |
3596 | XEXP (XEXP (x, 1), 1)); | |
230d793d RS |
3597 | break; |
3598 | ||
3599 | case MULT: | |
3600 | /* If we have (mult (plus A B) C), apply the distributive law and then | |
3601 | the inverse distributive law to see if things simplify. This | |
3602 | occurs mostly in addresses, often when unrolling loops. */ | |
3603 | ||
3604 | if (GET_CODE (XEXP (x, 0)) == PLUS) | |
3605 | { | |
3606 | x = apply_distributive_law | |
3607 | (gen_binary (PLUS, mode, | |
3608 | gen_binary (MULT, mode, | |
3609 | XEXP (XEXP (x, 0), 0), XEXP (x, 1)), | |
3610 | gen_binary (MULT, mode, | |
3611 | XEXP (XEXP (x, 0), 1), XEXP (x, 1)))); | |
3612 | ||
3613 | if (GET_CODE (x) != MULT) | |
8079805d | 3614 | return x; |
230d793d | 3615 | } |
230d793d RS |
3616 | break; |
3617 | ||
3618 | case UDIV: | |
3619 | /* If this is a divide by a power of two, treat it as a shift if | |
3620 | its first operand is a shift. */ | |
3621 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
3622 | && (i = exact_log2 (INTVAL (XEXP (x, 1)))) >= 0 | |
3623 | && (GET_CODE (XEXP (x, 0)) == ASHIFT | |
3624 | || GET_CODE (XEXP (x, 0)) == LSHIFTRT | |
3625 | || GET_CODE (XEXP (x, 0)) == ASHIFTRT | |
3626 | || GET_CODE (XEXP (x, 0)) == ROTATE | |
3627 | || GET_CODE (XEXP (x, 0)) == ROTATERT)) | |
8079805d | 3628 | return simplify_shift_const (NULL_RTX, LSHIFTRT, mode, XEXP (x, 0), i); |
230d793d RS |
3629 | break; |
3630 | ||
3631 | case EQ: case NE: | |
3632 | case GT: case GTU: case GE: case GEU: | |
3633 | case LT: case LTU: case LE: case LEU: | |
3634 | /* If the first operand is a condition code, we can't do anything | |
3635 | with it. */ | |
3636 | if (GET_CODE (XEXP (x, 0)) == COMPARE | |
3637 | || (GET_MODE_CLASS (GET_MODE (XEXP (x, 0))) != MODE_CC | |
3638 | #ifdef HAVE_cc0 | |
3639 | && XEXP (x, 0) != cc0_rtx | |
3640 | #endif | |
3641 | )) | |
3642 | { | |
3643 | rtx op0 = XEXP (x, 0); | |
3644 | rtx op1 = XEXP (x, 1); | |
3645 | enum rtx_code new_code; | |
3646 | ||
3647 | if (GET_CODE (op0) == COMPARE) | |
3648 | op1 = XEXP (op0, 1), op0 = XEXP (op0, 0); | |
3649 | ||
3650 | /* Simplify our comparison, if possible. */ | |
3651 | new_code = simplify_comparison (code, &op0, &op1); | |
3652 | ||
3653 | #if STORE_FLAG_VALUE == 1 | |
3654 | /* If STORE_FLAG_VALUE is 1, we can convert (ne x 0) to simply X | |
951553af | 3655 | if only the low-order bit is possibly nonzero in X (such as when |
5109d49f RK |
3656 | X is a ZERO_EXTRACT of one bit). Similarly, we can convert EQ to |
3657 | (xor X 1) or (minus 1 X); we use the former. Finally, if X is | |
3658 | known to be either 0 or -1, NE becomes a NEG and EQ becomes | |
3659 | (plus X 1). | |
3660 | ||
3661 | Remove any ZERO_EXTRACT we made when thinking this was a | |
3662 | comparison. It may now be simpler to use, e.g., an AND. If a | |
3663 | ZERO_EXTRACT is indeed appropriate, it will be placed back by | |
3664 | the call to make_compound_operation in the SET case. */ | |
3665 | ||
3f508eca | 3666 | if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT |
230d793d | 3667 | && op1 == const0_rtx |
5109d49f | 3668 | && nonzero_bits (op0, mode) == 1) |
818b11b9 RK |
3669 | return gen_lowpart_for_combine (mode, |
3670 | expand_compound_operation (op0)); | |
5109d49f RK |
3671 | |
3672 | else if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT | |
3673 | && op1 == const0_rtx | |
3674 | && (num_sign_bit_copies (op0, mode) | |
3675 | == GET_MODE_BITSIZE (mode))) | |
3676 | { | |
3677 | op0 = expand_compound_operation (op0); | |
0c1c8ea6 | 3678 | return gen_unary (NEG, mode, mode, |
8079805d | 3679 | gen_lowpart_for_combine (mode, op0)); |
5109d49f RK |
3680 | } |
3681 | ||
3f508eca | 3682 | else if (new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT |
230d793d | 3683 | && op1 == const0_rtx |
5109d49f | 3684 | && nonzero_bits (op0, mode) == 1) |
818b11b9 RK |
3685 | { |
3686 | op0 = expand_compound_operation (op0); | |
8079805d RK |
3687 | return gen_binary (XOR, mode, |
3688 | gen_lowpart_for_combine (mode, op0), | |
3689 | const1_rtx); | |
5109d49f | 3690 | } |
818b11b9 | 3691 | |
5109d49f RK |
3692 | else if (new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT |
3693 | && op1 == const0_rtx | |
3694 | && (num_sign_bit_copies (op0, mode) | |
3695 | == GET_MODE_BITSIZE (mode))) | |
3696 | { | |
3697 | op0 = expand_compound_operation (op0); | |
8079805d | 3698 | return plus_constant (gen_lowpart_for_combine (mode, op0), 1); |
818b11b9 | 3699 | } |
230d793d RS |
3700 | #endif |
3701 | ||
3702 | #if STORE_FLAG_VALUE == -1 | |
5109d49f RK |
3703 | /* If STORE_FLAG_VALUE is -1, we have cases similar to |
3704 | those above. */ | |
3f508eca | 3705 | if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT |
230d793d | 3706 | && op1 == const0_rtx |
5109d49f RK |
3707 | && (num_sign_bit_copies (op0, mode) |
3708 | == GET_MODE_BITSIZE (mode))) | |
3709 | return gen_lowpart_for_combine (mode, | |
3710 | expand_compound_operation (op0)); | |
3711 | ||
3712 | else if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT | |
3713 | && op1 == const0_rtx | |
3714 | && nonzero_bits (op0, mode) == 1) | |
3715 | { | |
3716 | op0 = expand_compound_operation (op0); | |
0c1c8ea6 | 3717 | return gen_unary (NEG, mode, mode, |
8079805d | 3718 | gen_lowpart_for_combine (mode, op0)); |
5109d49f RK |
3719 | } |
3720 | ||
3721 | else if (new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT | |
3722 | && op1 == const0_rtx | |
3723 | && (num_sign_bit_copies (op0, mode) | |
3724 | == GET_MODE_BITSIZE (mode))) | |
230d793d | 3725 | { |
818b11b9 | 3726 | op0 = expand_compound_operation (op0); |
0c1c8ea6 | 3727 | return gen_unary (NOT, mode, mode, |
8079805d | 3728 | gen_lowpart_for_combine (mode, op0)); |
5109d49f RK |
3729 | } |
3730 | ||
3731 | /* If X is 0/1, (eq X 0) is X-1. */ | |
3732 | else if (new_code == EQ && GET_MODE_CLASS (mode) == MODE_INT | |
3733 | && op1 == const0_rtx | |
3734 | && nonzero_bits (op0, mode) == 1) | |
3735 | { | |
3736 | op0 = expand_compound_operation (op0); | |
8079805d | 3737 | return plus_constant (gen_lowpart_for_combine (mode, op0), -1); |
230d793d RS |
3738 | } |
3739 | #endif | |
3740 | ||
3741 | /* If STORE_FLAG_VALUE says to just test the sign bit and X has just | |
951553af RK |
3742 | one bit that might be nonzero, we can convert (ne x 0) to |
3743 | (ashift x c) where C puts the bit in the sign bit. Remove any | |
3744 | AND with STORE_FLAG_VALUE when we are done, since we are only | |
3745 | going to test the sign bit. */ | |
3f508eca | 3746 | if (new_code == NE && GET_MODE_CLASS (mode) == MODE_INT |
5f4f0e22 CH |
3747 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
3748 | && (STORE_FLAG_VALUE | |
3749 | == (HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)) | |
230d793d RS |
3750 | && op1 == const0_rtx |
3751 | && mode == GET_MODE (op0) | |
5109d49f | 3752 | && (i = exact_log2 (nonzero_bits (op0, mode))) >= 0) |
230d793d | 3753 | { |
818b11b9 RK |
3754 | x = simplify_shift_const (NULL_RTX, ASHIFT, mode, |
3755 | expand_compound_operation (op0), | |
230d793d RS |
3756 | GET_MODE_BITSIZE (mode) - 1 - i); |
3757 | if (GET_CODE (x) == AND && XEXP (x, 1) == const_true_rtx) | |
3758 | return XEXP (x, 0); | |
3759 | else | |
3760 | return x; | |
3761 | } | |
3762 | ||
3763 | /* If the code changed, return a whole new comparison. */ | |
3764 | if (new_code != code) | |
3765 | return gen_rtx_combine (new_code, mode, op0, op1); | |
3766 | ||
3767 | /* Otherwise, keep this operation, but maybe change its operands. | |
3768 | This also converts (ne (compare FOO BAR) 0) to (ne FOO BAR). */ | |
3769 | SUBST (XEXP (x, 0), op0); | |
3770 | SUBST (XEXP (x, 1), op1); | |
3771 | } | |
3772 | break; | |
3773 | ||
3774 | case IF_THEN_ELSE: | |
8079805d | 3775 | return simplify_if_then_else (x); |
9210df58 | 3776 | |
8079805d RK |
3777 | case ZERO_EXTRACT: |
3778 | case SIGN_EXTRACT: | |
3779 | case ZERO_EXTEND: | |
3780 | case SIGN_EXTEND: | |
3781 | /* If we are processing SET_DEST, we are done. */ | |
3782 | if (in_dest) | |
3783 | return x; | |
d0ab8cd3 | 3784 | |
8079805d | 3785 | return expand_compound_operation (x); |
d0ab8cd3 | 3786 | |
8079805d RK |
3787 | case SET: |
3788 | return simplify_set (x); | |
1a26b032 | 3789 | |
8079805d RK |
3790 | case AND: |
3791 | case IOR: | |
3792 | case XOR: | |
3793 | return simplify_logical (x, last); | |
d0ab8cd3 | 3794 | |
8079805d RK |
3795 | case ABS: |
3796 | /* (abs (neg <foo>)) -> (abs <foo>) */ | |
3797 | if (GET_CODE (XEXP (x, 0)) == NEG) | |
3798 | SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); | |
1a26b032 | 3799 | |
8079805d RK |
3800 | /* If operand is something known to be positive, ignore the ABS. */ |
3801 | if (GET_CODE (XEXP (x, 0)) == FFS || GET_CODE (XEXP (x, 0)) == ABS | |
3802 | || ((GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) | |
3803 | <= HOST_BITS_PER_WIDE_INT) | |
3804 | && ((nonzero_bits (XEXP (x, 0), GET_MODE (XEXP (x, 0))) | |
3805 | & ((HOST_WIDE_INT) 1 | |
3806 | << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1))) | |
3807 | == 0))) | |
3808 | return XEXP (x, 0); | |
1a26b032 | 3809 | |
1a26b032 | 3810 | |
8079805d RK |
3811 | /* If operand is known to be only -1 or 0, convert ABS to NEG. */ |
3812 | if (num_sign_bit_copies (XEXP (x, 0), mode) == GET_MODE_BITSIZE (mode)) | |
3813 | return gen_rtx_combine (NEG, mode, XEXP (x, 0)); | |
1a26b032 | 3814 | |
8079805d | 3815 | break; |
1a26b032 | 3816 | |
8079805d RK |
3817 | case FFS: |
3818 | /* (ffs (*_extend <X>)) = (ffs <X>) */ | |
3819 | if (GET_CODE (XEXP (x, 0)) == SIGN_EXTEND | |
3820 | || GET_CODE (XEXP (x, 0)) == ZERO_EXTEND) | |
3821 | SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); | |
3822 | break; | |
1a26b032 | 3823 | |
8079805d RK |
3824 | case FLOAT: |
3825 | /* (float (sign_extend <X>)) = (float <X>). */ | |
3826 | if (GET_CODE (XEXP (x, 0)) == SIGN_EXTEND) | |
3827 | SUBST (XEXP (x, 0), XEXP (XEXP (x, 0), 0)); | |
3828 | break; | |
1a26b032 | 3829 | |
8079805d RK |
3830 | case ASHIFT: |
3831 | case LSHIFTRT: | |
3832 | case ASHIFTRT: | |
3833 | case ROTATE: | |
3834 | case ROTATERT: | |
3835 | /* If this is a shift by a constant amount, simplify it. */ | |
3836 | if (GET_CODE (XEXP (x, 1)) == CONST_INT) | |
3837 | return simplify_shift_const (x, code, mode, XEXP (x, 0), | |
3838 | INTVAL (XEXP (x, 1))); | |
3839 | ||
3840 | #ifdef SHIFT_COUNT_TRUNCATED | |
3841 | else if (SHIFT_COUNT_TRUNCATED && GET_CODE (XEXP (x, 1)) != REG) | |
3842 | SUBST (XEXP (x, 1), | |
3843 | force_to_mode (XEXP (x, 1), GET_MODE (x), | |
3844 | ((HOST_WIDE_INT) 1 | |
3845 | << exact_log2 (GET_MODE_BITSIZE (GET_MODE (x)))) | |
3846 | - 1, | |
3847 | NULL_RTX, 0)); | |
3848 | #endif | |
3849 | ||
3850 | break; | |
3851 | } | |
3852 | ||
3853 | return x; | |
3854 | } | |
3855 | \f | |
3856 | /* Simplify X, an IF_THEN_ELSE expression. Return the new expression. */ | |
5109d49f | 3857 | |
8079805d RK |
3858 | static rtx |
3859 | simplify_if_then_else (x) | |
3860 | rtx x; | |
3861 | { | |
3862 | enum machine_mode mode = GET_MODE (x); | |
3863 | rtx cond = XEXP (x, 0); | |
3864 | rtx true = XEXP (x, 1); | |
3865 | rtx false = XEXP (x, 2); | |
3866 | enum rtx_code true_code = GET_CODE (cond); | |
3867 | int comparison_p = GET_RTX_CLASS (true_code) == '<'; | |
3868 | rtx temp; | |
3869 | int i; | |
3870 | ||
3871 | /* Simplify storing of the truth value. */ | |
3872 | if (comparison_p && true == const_true_rtx && false == const0_rtx) | |
3873 | return gen_binary (true_code, mode, XEXP (cond, 0), XEXP (cond, 1)); | |
3874 | ||
3875 | /* Also when the truth value has to be reversed. */ | |
3876 | if (comparison_p && reversible_comparison_p (cond) | |
3877 | && true == const0_rtx && false == const_true_rtx) | |
3878 | return gen_binary (reverse_condition (true_code), | |
3879 | mode, XEXP (cond, 0), XEXP (cond, 1)); | |
3880 | ||
3881 | /* Sometimes we can simplify the arm of an IF_THEN_ELSE if a register used | |
3882 | in it is being compared against certain values. Get the true and false | |
3883 | comparisons and see if that says anything about the value of each arm. */ | |
3884 | ||
3885 | if (comparison_p && reversible_comparison_p (cond) | |
3886 | && GET_CODE (XEXP (cond, 0)) == REG) | |
3887 | { | |
3888 | HOST_WIDE_INT nzb; | |
3889 | rtx from = XEXP (cond, 0); | |
3890 | enum rtx_code false_code = reverse_condition (true_code); | |
3891 | rtx true_val = XEXP (cond, 1); | |
3892 | rtx false_val = true_val; | |
3893 | int swapped = 0; | |
9210df58 | 3894 | |
8079805d | 3895 | /* If FALSE_CODE is EQ, swap the codes and arms. */ |
5109d49f | 3896 | |
8079805d | 3897 | if (false_code == EQ) |
1a26b032 | 3898 | { |
8079805d RK |
3899 | swapped = 1, true_code = EQ, false_code = NE; |
3900 | temp = true, true = false, false = temp; | |
3901 | } | |
5109d49f | 3902 | |
8079805d RK |
3903 | /* If we are comparing against zero and the expression being tested has |
3904 | only a single bit that might be nonzero, that is its value when it is | |
3905 | not equal to zero. Similarly if it is known to be -1 or 0. */ | |
3906 | ||
3907 | if (true_code == EQ && true_val == const0_rtx | |
3908 | && exact_log2 (nzb = nonzero_bits (from, GET_MODE (from))) >= 0) | |
3909 | false_code = EQ, false_val = GEN_INT (nzb); | |
3910 | else if (true_code == EQ && true_val == const0_rtx | |
3911 | && (num_sign_bit_copies (from, GET_MODE (from)) | |
3912 | == GET_MODE_BITSIZE (GET_MODE (from)))) | |
3913 | false_code = EQ, false_val = constm1_rtx; | |
3914 | ||
3915 | /* Now simplify an arm if we know the value of the register in the | |
3916 | branch and it is used in the arm. Be careful due to the potential | |
3917 | of locally-shared RTL. */ | |
3918 | ||
3919 | if (reg_mentioned_p (from, true)) | |
3920 | true = subst (known_cond (copy_rtx (true), true_code, from, true_val), | |
3921 | pc_rtx, pc_rtx, 0, 0); | |
3922 | if (reg_mentioned_p (from, false)) | |
3923 | false = subst (known_cond (copy_rtx (false), false_code, | |
3924 | from, false_val), | |
3925 | pc_rtx, pc_rtx, 0, 0); | |
3926 | ||
3927 | SUBST (XEXP (x, 1), swapped ? false : true); | |
3928 | SUBST (XEXP (x, 2), swapped ? true : false); | |
3929 | ||
3930 | true = XEXP (x, 1), false = XEXP (x, 2), true_code = GET_CODE (cond); | |
3931 | } | |
5109d49f | 3932 | |
8079805d RK |
3933 | /* If we have (if_then_else FOO (pc) (label_ref BAR)) and FOO can be |
3934 | reversed, do so to avoid needing two sets of patterns for | |
3935 | subtract-and-branch insns. Similarly if we have a constant in the true | |
3936 | arm, the false arm is the same as the first operand of the comparison, or | |
3937 | the false arm is more complicated than the true arm. */ | |
3938 | ||
3939 | if (comparison_p && reversible_comparison_p (cond) | |
3940 | && (true == pc_rtx | |
3941 | || (CONSTANT_P (true) | |
3942 | && GET_CODE (false) != CONST_INT && false != pc_rtx) | |
3943 | || true == const0_rtx | |
3944 | || (GET_RTX_CLASS (GET_CODE (true)) == 'o' | |
3945 | && GET_RTX_CLASS (GET_CODE (false)) != 'o') | |
3946 | || (GET_CODE (true) == SUBREG | |
3947 | && GET_RTX_CLASS (GET_CODE (SUBREG_REG (true))) == 'o' | |
3948 | && GET_RTX_CLASS (GET_CODE (false)) != 'o') | |
3949 | || reg_mentioned_p (true, false) | |
3950 | || rtx_equal_p (false, XEXP (cond, 0)))) | |
3951 | { | |
3952 | true_code = reverse_condition (true_code); | |
3953 | SUBST (XEXP (x, 0), | |
3954 | gen_binary (true_code, GET_MODE (cond), XEXP (cond, 0), | |
3955 | XEXP (cond, 1))); | |
5109d49f | 3956 | |
8079805d RK |
3957 | SUBST (XEXP (x, 1), false); |
3958 | SUBST (XEXP (x, 2), true); | |
1a26b032 | 3959 | |
8079805d RK |
3960 | temp = true, true = false, false = temp, cond = XEXP (x, 0); |
3961 | } | |
abe6e52f | 3962 | |
8079805d | 3963 | /* If the two arms are identical, we don't need the comparison. */ |
1a26b032 | 3964 | |
8079805d RK |
3965 | if (rtx_equal_p (true, false) && ! side_effects_p (cond)) |
3966 | return true; | |
1a26b032 | 3967 | |
8079805d RK |
3968 | /* Look for cases where we have (abs x) or (neg (abs X)). */ |
3969 | ||
3970 | if (GET_MODE_CLASS (mode) == MODE_INT | |
3971 | && GET_CODE (false) == NEG | |
3972 | && rtx_equal_p (true, XEXP (false, 0)) | |
3973 | && comparison_p | |
3974 | && rtx_equal_p (true, XEXP (cond, 0)) | |
3975 | && ! side_effects_p (true)) | |
3976 | switch (true_code) | |
3977 | { | |
3978 | case GT: | |
3979 | case GE: | |
0c1c8ea6 | 3980 | return gen_unary (ABS, mode, mode, true); |
8079805d RK |
3981 | case LT: |
3982 | case LE: | |
0c1c8ea6 | 3983 | return gen_unary (NEG, mode, mode, gen_unary (ABS, mode, mode, true)); |
8079805d RK |
3984 | } |
3985 | ||
3986 | /* Look for MIN or MAX. */ | |
3987 | ||
3988 | if ((! FLOAT_MODE_P (mode) | flag_fast_math) | |
3989 | && comparison_p | |
3990 | && rtx_equal_p (XEXP (cond, 0), true) | |
3991 | && rtx_equal_p (XEXP (cond, 1), false) | |
3992 | && ! side_effects_p (cond)) | |
3993 | switch (true_code) | |
3994 | { | |
3995 | case GE: | |
3996 | case GT: | |
3997 | return gen_binary (SMAX, mode, true, false); | |
3998 | case LE: | |
3999 | case LT: | |
4000 | return gen_binary (SMIN, mode, true, false); | |
4001 | case GEU: | |
4002 | case GTU: | |
4003 | return gen_binary (UMAX, mode, true, false); | |
4004 | case LEU: | |
4005 | case LTU: | |
4006 | return gen_binary (UMIN, mode, true, false); | |
4007 | } | |
4008 | ||
4009 | #if STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1 | |
4010 | ||
4011 | /* If we have (if_then_else COND (OP Z C1) Z) and OP is an identity when its | |
4012 | second operand is zero, this can be done as (OP Z (mult COND C2)) where | |
4013 | C2 = C1 * STORE_FLAG_VALUE. Similarly if OP has an outer ZERO_EXTEND or | |
4014 | SIGN_EXTEND as long as Z is already extended (so we don't destroy it). | |
4015 | We can do this kind of thing in some cases when STORE_FLAG_VALUE is | |
d5a4ebdc | 4016 | neither of the above, but it isn't worth checking for. */ |
8079805d RK |
4017 | |
4018 | if (comparison_p && mode != VOIDmode && ! side_effects_p (x)) | |
4019 | { | |
4020 | rtx t = make_compound_operation (true, SET); | |
4021 | rtx f = make_compound_operation (false, SET); | |
4022 | rtx cond_op0 = XEXP (cond, 0); | |
4023 | rtx cond_op1 = XEXP (cond, 1); | |
4024 | enum rtx_code op, extend_op = NIL; | |
4025 | enum machine_mode m = mode; | |
f24ad0e4 | 4026 | rtx z = 0, c1; |
8079805d | 4027 | |
8079805d RK |
4028 | if ((GET_CODE (t) == PLUS || GET_CODE (t) == MINUS |
4029 | || GET_CODE (t) == IOR || GET_CODE (t) == XOR | |
4030 | || GET_CODE (t) == ASHIFT | |
4031 | || GET_CODE (t) == LSHIFTRT || GET_CODE (t) == ASHIFTRT) | |
4032 | && rtx_equal_p (XEXP (t, 0), f)) | |
4033 | c1 = XEXP (t, 1), op = GET_CODE (t), z = f; | |
4034 | ||
4035 | /* If an identity-zero op is commutative, check whether there | |
4036 | would be a match if we swapped the operands. */ | |
4037 | else if ((GET_CODE (t) == PLUS || GET_CODE (t) == IOR | |
4038 | || GET_CODE (t) == XOR) | |
4039 | && rtx_equal_p (XEXP (t, 1), f)) | |
4040 | c1 = XEXP (t, 0), op = GET_CODE (t), z = f; | |
4041 | else if (GET_CODE (t) == SIGN_EXTEND | |
4042 | && (GET_CODE (XEXP (t, 0)) == PLUS | |
4043 | || GET_CODE (XEXP (t, 0)) == MINUS | |
4044 | || GET_CODE (XEXP (t, 0)) == IOR | |
4045 | || GET_CODE (XEXP (t, 0)) == XOR | |
4046 | || GET_CODE (XEXP (t, 0)) == ASHIFT | |
4047 | || GET_CODE (XEXP (t, 0)) == LSHIFTRT | |
4048 | || GET_CODE (XEXP (t, 0)) == ASHIFTRT) | |
4049 | && GET_CODE (XEXP (XEXP (t, 0), 0)) == SUBREG | |
4050 | && subreg_lowpart_p (XEXP (XEXP (t, 0), 0)) | |
4051 | && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 0)), f) | |
4052 | && (num_sign_bit_copies (f, GET_MODE (f)) | |
4053 | > (GET_MODE_BITSIZE (mode) | |
4054 | - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t, 0), 0)))))) | |
4055 | { | |
4056 | c1 = XEXP (XEXP (t, 0), 1); z = f; op = GET_CODE (XEXP (t, 0)); | |
4057 | extend_op = SIGN_EXTEND; | |
4058 | m = GET_MODE (XEXP (t, 0)); | |
1a26b032 | 4059 | } |
8079805d RK |
4060 | else if (GET_CODE (t) == SIGN_EXTEND |
4061 | && (GET_CODE (XEXP (t, 0)) == PLUS | |
4062 | || GET_CODE (XEXP (t, 0)) == IOR | |
4063 | || GET_CODE (XEXP (t, 0)) == XOR) | |
4064 | && GET_CODE (XEXP (XEXP (t, 0), 1)) == SUBREG | |
4065 | && subreg_lowpart_p (XEXP (XEXP (t, 0), 1)) | |
4066 | && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 1)), f) | |
4067 | && (num_sign_bit_copies (f, GET_MODE (f)) | |
4068 | > (GET_MODE_BITSIZE (mode) | |
4069 | - GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (t, 0), 1)))))) | |
4070 | { | |
4071 | c1 = XEXP (XEXP (t, 0), 0); z = f; op = GET_CODE (XEXP (t, 0)); | |
4072 | extend_op = SIGN_EXTEND; | |
4073 | m = GET_MODE (XEXP (t, 0)); | |
4074 | } | |
4075 | else if (GET_CODE (t) == ZERO_EXTEND | |
4076 | && (GET_CODE (XEXP (t, 0)) == PLUS | |
4077 | || GET_CODE (XEXP (t, 0)) == MINUS | |
4078 | || GET_CODE (XEXP (t, 0)) == IOR | |
4079 | || GET_CODE (XEXP (t, 0)) == XOR | |
4080 | || GET_CODE (XEXP (t, 0)) == ASHIFT | |
4081 | || GET_CODE (XEXP (t, 0)) == LSHIFTRT | |
4082 | || GET_CODE (XEXP (t, 0)) == ASHIFTRT) | |
4083 | && GET_CODE (XEXP (XEXP (t, 0), 0)) == SUBREG | |
4084 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT | |
4085 | && subreg_lowpart_p (XEXP (XEXP (t, 0), 0)) | |
4086 | && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 0)), f) | |
4087 | && ((nonzero_bits (f, GET_MODE (f)) | |
4088 | & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t, 0), 0)))) | |
4089 | == 0)) | |
4090 | { | |
4091 | c1 = XEXP (XEXP (t, 0), 1); z = f; op = GET_CODE (XEXP (t, 0)); | |
4092 | extend_op = ZERO_EXTEND; | |
4093 | m = GET_MODE (XEXP (t, 0)); | |
4094 | } | |
4095 | else if (GET_CODE (t) == ZERO_EXTEND | |
4096 | && (GET_CODE (XEXP (t, 0)) == PLUS | |
4097 | || GET_CODE (XEXP (t, 0)) == IOR | |
4098 | || GET_CODE (XEXP (t, 0)) == XOR) | |
4099 | && GET_CODE (XEXP (XEXP (t, 0), 1)) == SUBREG | |
4100 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT | |
4101 | && subreg_lowpart_p (XEXP (XEXP (t, 0), 1)) | |
4102 | && rtx_equal_p (SUBREG_REG (XEXP (XEXP (t, 0), 1)), f) | |
4103 | && ((nonzero_bits (f, GET_MODE (f)) | |
4104 | & ~ GET_MODE_MASK (GET_MODE (XEXP (XEXP (t, 0), 1)))) | |
4105 | == 0)) | |
4106 | { | |
4107 | c1 = XEXP (XEXP (t, 0), 0); z = f; op = GET_CODE (XEXP (t, 0)); | |
4108 | extend_op = ZERO_EXTEND; | |
4109 | m = GET_MODE (XEXP (t, 0)); | |
4110 | } | |
4111 | ||
4112 | if (z) | |
4113 | { | |
4114 | temp = subst (gen_binary (true_code, m, cond_op0, cond_op1), | |
4115 | pc_rtx, pc_rtx, 0, 0); | |
4116 | temp = gen_binary (MULT, m, temp, | |
4117 | gen_binary (MULT, m, c1, const_true_rtx)); | |
4118 | temp = subst (temp, pc_rtx, pc_rtx, 0, 0); | |
4119 | temp = gen_binary (op, m, gen_lowpart_for_combine (m, z), temp); | |
4120 | ||
4121 | if (extend_op != NIL) | |
0c1c8ea6 | 4122 | temp = gen_unary (extend_op, mode, m, temp); |
8079805d RK |
4123 | |
4124 | return temp; | |
4125 | } | |
4126 | } | |
5109d49f | 4127 | #endif |
224eeff2 | 4128 | |
8079805d RK |
4129 | /* If we have (if_then_else (ne A 0) C1 0) and either A is known to be 0 or |
4130 | 1 and C1 is a single bit or A is known to be 0 or -1 and C1 is the | |
4131 | negation of a single bit, we can convert this operation to a shift. We | |
4132 | can actually do this more generally, but it doesn't seem worth it. */ | |
4133 | ||
4134 | if (true_code == NE && XEXP (cond, 1) == const0_rtx | |
4135 | && false == const0_rtx && GET_CODE (true) == CONST_INT | |
4136 | && ((1 == nonzero_bits (XEXP (cond, 0), mode) | |
4137 | && (i = exact_log2 (INTVAL (true))) >= 0) | |
4138 | || ((num_sign_bit_copies (XEXP (cond, 0), mode) | |
4139 | == GET_MODE_BITSIZE (mode)) | |
4140 | && (i = exact_log2 (- INTVAL (true))) >= 0))) | |
4141 | return | |
4142 | simplify_shift_const (NULL_RTX, ASHIFT, mode, | |
4143 | gen_lowpart_for_combine (mode, XEXP (cond, 0)), i); | |
230d793d | 4144 | |
8079805d RK |
4145 | return x; |
4146 | } | |
4147 | \f | |
4148 | /* Simplify X, a SET expression. Return the new expression. */ | |
230d793d | 4149 | |
8079805d RK |
4150 | static rtx |
4151 | simplify_set (x) | |
4152 | rtx x; | |
4153 | { | |
4154 | rtx src = SET_SRC (x); | |
4155 | rtx dest = SET_DEST (x); | |
4156 | enum machine_mode mode | |
4157 | = GET_MODE (src) != VOIDmode ? GET_MODE (src) : GET_MODE (dest); | |
4158 | rtx other_insn; | |
4159 | rtx *cc_use; | |
4160 | ||
4161 | /* (set (pc) (return)) gets written as (return). */ | |
4162 | if (GET_CODE (dest) == PC && GET_CODE (src) == RETURN) | |
4163 | return src; | |
230d793d | 4164 | |
87e3e0c1 RK |
4165 | /* Now that we know for sure which bits of SRC we are using, see if we can |
4166 | simplify the expression for the object knowing that we only need the | |
4167 | low-order bits. */ | |
4168 | ||
4169 | if (GET_MODE_CLASS (mode) == MODE_INT) | |
4170 | src = force_to_mode (src, mode, GET_MODE_MASK (mode), NULL_RTX, 0); | |
4171 | ||
8079805d RK |
4172 | /* If we are setting CC0 or if the source is a COMPARE, look for the use of |
4173 | the comparison result and try to simplify it unless we already have used | |
4174 | undobuf.other_insn. */ | |
4175 | if ((GET_CODE (src) == COMPARE | |
230d793d | 4176 | #ifdef HAVE_cc0 |
8079805d | 4177 | || dest == cc0_rtx |
230d793d | 4178 | #endif |
8079805d RK |
4179 | ) |
4180 | && (cc_use = find_single_use (dest, subst_insn, &other_insn)) != 0 | |
4181 | && (undobuf.other_insn == 0 || other_insn == undobuf.other_insn) | |
4182 | && GET_RTX_CLASS (GET_CODE (*cc_use)) == '<' | |
c0d3ac4d | 4183 | && rtx_equal_p (XEXP (*cc_use, 0), dest)) |
8079805d RK |
4184 | { |
4185 | enum rtx_code old_code = GET_CODE (*cc_use); | |
4186 | enum rtx_code new_code; | |
4187 | rtx op0, op1; | |
4188 | int other_changed = 0; | |
4189 | enum machine_mode compare_mode = GET_MODE (dest); | |
4190 | ||
4191 | if (GET_CODE (src) == COMPARE) | |
4192 | op0 = XEXP (src, 0), op1 = XEXP (src, 1); | |
4193 | else | |
4194 | op0 = src, op1 = const0_rtx; | |
230d793d | 4195 | |
8079805d RK |
4196 | /* Simplify our comparison, if possible. */ |
4197 | new_code = simplify_comparison (old_code, &op0, &op1); | |
230d793d | 4198 | |
c141a106 | 4199 | #ifdef EXTRA_CC_MODES |
8079805d RK |
4200 | /* If this machine has CC modes other than CCmode, check to see if we |
4201 | need to use a different CC mode here. */ | |
4202 | compare_mode = SELECT_CC_MODE (new_code, op0, op1); | |
c141a106 | 4203 | #endif /* EXTRA_CC_MODES */ |
230d793d | 4204 | |
c141a106 | 4205 | #if !defined (HAVE_cc0) && defined (EXTRA_CC_MODES) |
8079805d RK |
4206 | /* If the mode changed, we have to change SET_DEST, the mode in the |
4207 | compare, and the mode in the place SET_DEST is used. If SET_DEST is | |
4208 | a hard register, just build new versions with the proper mode. If it | |
4209 | is a pseudo, we lose unless it is only time we set the pseudo, in | |
4210 | which case we can safely change its mode. */ | |
4211 | if (compare_mode != GET_MODE (dest)) | |
4212 | { | |
4213 | int regno = REGNO (dest); | |
4214 | rtx new_dest = gen_rtx (REG, compare_mode, regno); | |
4215 | ||
4216 | if (regno < FIRST_PSEUDO_REGISTER | |
4217 | || (reg_n_sets[regno] == 1 && ! REG_USERVAR_P (dest))) | |
230d793d | 4218 | { |
8079805d RK |
4219 | if (regno >= FIRST_PSEUDO_REGISTER) |
4220 | SUBST (regno_reg_rtx[regno], new_dest); | |
230d793d | 4221 | |
8079805d RK |
4222 | SUBST (SET_DEST (x), new_dest); |
4223 | SUBST (XEXP (*cc_use, 0), new_dest); | |
4224 | other_changed = 1; | |
230d793d | 4225 | |
8079805d | 4226 | dest = new_dest; |
230d793d | 4227 | } |
8079805d | 4228 | } |
230d793d RS |
4229 | #endif |
4230 | ||
8079805d RK |
4231 | /* If the code changed, we have to build a new comparison in |
4232 | undobuf.other_insn. */ | |
4233 | if (new_code != old_code) | |
4234 | { | |
4235 | unsigned HOST_WIDE_INT mask; | |
4236 | ||
4237 | SUBST (*cc_use, gen_rtx_combine (new_code, GET_MODE (*cc_use), | |
4238 | dest, const0_rtx)); | |
4239 | ||
4240 | /* If the only change we made was to change an EQ into an NE or | |
4241 | vice versa, OP0 has only one bit that might be nonzero, and OP1 | |
4242 | is zero, check if changing the user of the condition code will | |
4243 | produce a valid insn. If it won't, we can keep the original code | |
4244 | in that insn by surrounding our operation with an XOR. */ | |
4245 | ||
4246 | if (((old_code == NE && new_code == EQ) | |
4247 | || (old_code == EQ && new_code == NE)) | |
4248 | && ! other_changed && op1 == const0_rtx | |
4249 | && GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT | |
4250 | && exact_log2 (mask = nonzero_bits (op0, GET_MODE (op0))) >= 0) | |
230d793d | 4251 | { |
8079805d | 4252 | rtx pat = PATTERN (other_insn), note = 0; |
230d793d | 4253 | |
8079805d RK |
4254 | if ((recog_for_combine (&pat, other_insn, ¬e) < 0 |
4255 | && ! check_asm_operands (pat))) | |
4256 | { | |
4257 | PUT_CODE (*cc_use, old_code); | |
4258 | other_insn = 0; | |
230d793d | 4259 | |
8079805d | 4260 | op0 = gen_binary (XOR, GET_MODE (op0), op0, GEN_INT (mask)); |
230d793d | 4261 | } |
230d793d RS |
4262 | } |
4263 | ||
8079805d RK |
4264 | other_changed = 1; |
4265 | } | |
4266 | ||
4267 | if (other_changed) | |
4268 | undobuf.other_insn = other_insn; | |
230d793d RS |
4269 | |
4270 | #ifdef HAVE_cc0 | |
8079805d RK |
4271 | /* If we are now comparing against zero, change our source if |
4272 | needed. If we do not use cc0, we always have a COMPARE. */ | |
4273 | if (op1 == const0_rtx && dest == cc0_rtx) | |
4274 | { | |
4275 | SUBST (SET_SRC (x), op0); | |
4276 | src = op0; | |
4277 | } | |
4278 | else | |
230d793d RS |
4279 | #endif |
4280 | ||
8079805d RK |
4281 | /* Otherwise, if we didn't previously have a COMPARE in the |
4282 | correct mode, we need one. */ | |
4283 | if (GET_CODE (src) != COMPARE || GET_MODE (src) != compare_mode) | |
4284 | { | |
4285 | SUBST (SET_SRC (x), | |
4286 | gen_rtx_combine (COMPARE, compare_mode, op0, op1)); | |
4287 | src = SET_SRC (x); | |
230d793d RS |
4288 | } |
4289 | else | |
4290 | { | |
8079805d RK |
4291 | /* Otherwise, update the COMPARE if needed. */ |
4292 | SUBST (XEXP (src, 0), op0); | |
4293 | SUBST (XEXP (src, 1), op1); | |
230d793d | 4294 | } |
8079805d RK |
4295 | } |
4296 | else | |
4297 | { | |
4298 | /* Get SET_SRC in a form where we have placed back any | |
4299 | compound expressions. Then do the checks below. */ | |
4300 | src = make_compound_operation (src, SET); | |
4301 | SUBST (SET_SRC (x), src); | |
4302 | } | |
230d793d | 4303 | |
8079805d RK |
4304 | /* If we have (set x (subreg:m1 (op:m2 ...) 0)) with OP being some operation, |
4305 | and X being a REG or (subreg (reg)), we may be able to convert this to | |
4306 | (set (subreg:m2 x) (op)). | |
df62f951 | 4307 | |
8079805d RK |
4308 | We can always do this if M1 is narrower than M2 because that means that |
4309 | we only care about the low bits of the result. | |
df62f951 | 4310 | |
8079805d RK |
4311 | However, on machines without WORD_REGISTER_OPERATIONS defined, we cannot |
4312 | perform a narrower operation that requested since the high-order bits will | |
4313 | be undefined. On machine where it is defined, this transformation is safe | |
4314 | as long as M1 and M2 have the same number of words. */ | |
df62f951 | 4315 | |
8079805d RK |
4316 | if (GET_CODE (src) == SUBREG && subreg_lowpart_p (src) |
4317 | && GET_RTX_CLASS (GET_CODE (SUBREG_REG (src))) != 'o' | |
4318 | && (((GET_MODE_SIZE (GET_MODE (src)) + (UNITS_PER_WORD - 1)) | |
4319 | / UNITS_PER_WORD) | |
4320 | == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (src))) | |
4321 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)) | |
8baf60bb | 4322 | #ifndef WORD_REGISTER_OPERATIONS |
8079805d RK |
4323 | && (GET_MODE_SIZE (GET_MODE (src)) |
4324 | < GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))) | |
df62f951 | 4325 | #endif |
8079805d RK |
4326 | && (GET_CODE (dest) == REG |
4327 | || (GET_CODE (dest) == SUBREG | |
4328 | && GET_CODE (SUBREG_REG (dest)) == REG))) | |
4329 | { | |
4330 | SUBST (SET_DEST (x), | |
4331 | gen_lowpart_for_combine (GET_MODE (SUBREG_REG (src)), | |
4332 | dest)); | |
4333 | SUBST (SET_SRC (x), SUBREG_REG (src)); | |
4334 | ||
4335 | src = SET_SRC (x), dest = SET_DEST (x); | |
4336 | } | |
df62f951 | 4337 | |
8baf60bb | 4338 | #ifdef LOAD_EXTEND_OP |
8079805d RK |
4339 | /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with M wider than N, this |
4340 | would require a paradoxical subreg. Replace the subreg with a | |
4341 | zero_extend to avoid the reload that would otherwise be required. */ | |
4342 | ||
4343 | if (GET_CODE (src) == SUBREG && subreg_lowpart_p (src) | |
4344 | && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src))) != NIL | |
4345 | && SUBREG_WORD (src) == 0 | |
4346 | && (GET_MODE_SIZE (GET_MODE (src)) | |
4347 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))) | |
4348 | && GET_CODE (SUBREG_REG (src)) == MEM) | |
4349 | { | |
4350 | SUBST (SET_SRC (x), | |
4351 | gen_rtx_combine (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (src))), | |
4352 | GET_MODE (src), XEXP (src, 0))); | |
4353 | ||
4354 | src = SET_SRC (x); | |
4355 | } | |
230d793d RS |
4356 | #endif |
4357 | ||
8079805d RK |
4358 | /* If we don't have a conditional move, SET_SRC is an IF_THEN_ELSE, and we |
4359 | are comparing an item known to be 0 or -1 against 0, use a logical | |
4360 | operation instead. Check for one of the arms being an IOR of the other | |
4361 | arm with some value. We compute three terms to be IOR'ed together. In | |
4362 | practice, at most two will be nonzero. Then we do the IOR's. */ | |
4363 | ||
4364 | if (GET_CODE (dest) != PC | |
4365 | && GET_CODE (src) == IF_THEN_ELSE | |
094030c9 DE |
4366 | #ifdef HAVE_conditional_move |
4367 | && ! HAVE_conditional_move | |
4368 | #endif | |
36b8d792 | 4369 | && GET_MODE_CLASS (GET_MODE (src)) == MODE_INT |
8079805d RK |
4370 | && (GET_CODE (XEXP (src, 0)) == EQ || GET_CODE (XEXP (src, 0)) == NE) |
4371 | && XEXP (XEXP (src, 0), 1) == const0_rtx | |
4372 | && (num_sign_bit_copies (XEXP (XEXP (src, 0), 0), | |
4373 | GET_MODE (XEXP (XEXP (src, 0), 0))) | |
4374 | == GET_MODE_BITSIZE (GET_MODE (XEXP (XEXP (src, 0), 0)))) | |
4375 | && ! side_effects_p (src)) | |
4376 | { | |
4377 | rtx true = (GET_CODE (XEXP (src, 0)) == NE | |
4378 | ? XEXP (src, 1) : XEXP (src, 2)); | |
4379 | rtx false = (GET_CODE (XEXP (src, 0)) == NE | |
4380 | ? XEXP (src, 2) : XEXP (src, 1)); | |
4381 | rtx term1 = const0_rtx, term2, term3; | |
4382 | ||
4383 | if (GET_CODE (true) == IOR && rtx_equal_p (XEXP (true, 0), false)) | |
4384 | term1 = false, true = XEXP (true, 1), false = const0_rtx; | |
4385 | else if (GET_CODE (true) == IOR | |
4386 | && rtx_equal_p (XEXP (true, 1), false)) | |
4387 | term1 = false, true = XEXP (true, 0), false = const0_rtx; | |
4388 | else if (GET_CODE (false) == IOR | |
4389 | && rtx_equal_p (XEXP (false, 0), true)) | |
4390 | term1 = true, false = XEXP (false, 1), true = const0_rtx; | |
4391 | else if (GET_CODE (false) == IOR | |
4392 | && rtx_equal_p (XEXP (false, 1), true)) | |
4393 | term1 = true, false = XEXP (false, 0), true = const0_rtx; | |
4394 | ||
4395 | term2 = gen_binary (AND, GET_MODE (src), XEXP (XEXP (src, 0), 0), true); | |
4396 | term3 = gen_binary (AND, GET_MODE (src), | |
0c1c8ea6 | 4397 | gen_unary (NOT, GET_MODE (src), GET_MODE (src), |
8079805d RK |
4398 | XEXP (XEXP (src, 0), 0)), |
4399 | false); | |
4400 | ||
4401 | SUBST (SET_SRC (x), | |
4402 | gen_binary (IOR, GET_MODE (src), | |
4403 | gen_binary (IOR, GET_MODE (src), term1, term2), | |
4404 | term3)); | |
4405 | ||
4406 | src = SET_SRC (x); | |
4407 | } | |
230d793d | 4408 | |
246e00f2 RK |
4409 | /* If either SRC or DEST is a CLOBBER of (const_int 0), make this |
4410 | whole thing fail. */ | |
4411 | if (GET_CODE (src) == CLOBBER && XEXP (src, 0) == const0_rtx) | |
4412 | return src; | |
4413 | else if (GET_CODE (dest) == CLOBBER && XEXP (dest, 0) == const0_rtx) | |
4414 | return dest; | |
4415 | else | |
4416 | /* Convert this into a field assignment operation, if possible. */ | |
4417 | return make_field_assignment (x); | |
8079805d RK |
4418 | } |
4419 | \f | |
4420 | /* Simplify, X, and AND, IOR, or XOR operation, and return the simplified | |
4421 | result. LAST is nonzero if this is the last retry. */ | |
4422 | ||
4423 | static rtx | |
4424 | simplify_logical (x, last) | |
4425 | rtx x; | |
4426 | int last; | |
4427 | { | |
4428 | enum machine_mode mode = GET_MODE (x); | |
4429 | rtx op0 = XEXP (x, 0); | |
4430 | rtx op1 = XEXP (x, 1); | |
4431 | ||
4432 | switch (GET_CODE (x)) | |
4433 | { | |
230d793d | 4434 | case AND: |
8079805d RK |
4435 | /* Convert (A ^ B) & A to A & (~ B) since the latter is often a single |
4436 | insn (and may simplify more). */ | |
4437 | if (GET_CODE (op0) == XOR | |
4438 | && rtx_equal_p (XEXP (op0, 0), op1) | |
4439 | && ! side_effects_p (op1)) | |
0c1c8ea6 RK |
4440 | x = gen_binary (AND, mode, |
4441 | gen_unary (NOT, mode, mode, XEXP (op0, 1)), op1); | |
8079805d RK |
4442 | |
4443 | if (GET_CODE (op0) == XOR | |
4444 | && rtx_equal_p (XEXP (op0, 1), op1) | |
4445 | && ! side_effects_p (op1)) | |
0c1c8ea6 RK |
4446 | x = gen_binary (AND, mode, |
4447 | gen_unary (NOT, mode, mode, XEXP (op0, 0)), op1); | |
8079805d RK |
4448 | |
4449 | /* Similarly for (~ (A ^ B)) & A. */ | |
4450 | if (GET_CODE (op0) == NOT | |
4451 | && GET_CODE (XEXP (op0, 0)) == XOR | |
4452 | && rtx_equal_p (XEXP (XEXP (op0, 0), 0), op1) | |
4453 | && ! side_effects_p (op1)) | |
4454 | x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 1), op1); | |
4455 | ||
4456 | if (GET_CODE (op0) == NOT | |
4457 | && GET_CODE (XEXP (op0, 0)) == XOR | |
4458 | && rtx_equal_p (XEXP (XEXP (op0, 0), 1), op1) | |
4459 | && ! side_effects_p (op1)) | |
4460 | x = gen_binary (AND, mode, XEXP (XEXP (op0, 0), 0), op1); | |
4461 | ||
4462 | if (GET_CODE (op1) == CONST_INT) | |
230d793d | 4463 | { |
8079805d | 4464 | x = simplify_and_const_int (x, mode, op0, INTVAL (op1)); |
230d793d RS |
4465 | |
4466 | /* If we have (ior (and (X C1) C2)) and the next restart would be | |
4467 | the last, simplify this by making C1 as small as possible | |
4468 | and then exit. */ | |
8079805d RK |
4469 | if (last |
4470 | && GET_CODE (x) == IOR && GET_CODE (op0) == AND | |
4471 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
4472 | && GET_CODE (op1) == CONST_INT) | |
4473 | return gen_binary (IOR, mode, | |
4474 | gen_binary (AND, mode, XEXP (op0, 0), | |
4475 | GEN_INT (INTVAL (XEXP (op0, 1)) | |
4476 | & ~ INTVAL (op1))), op1); | |
230d793d RS |
4477 | |
4478 | if (GET_CODE (x) != AND) | |
8079805d | 4479 | return x; |
230d793d RS |
4480 | } |
4481 | ||
4482 | /* Convert (A | B) & A to A. */ | |
8079805d RK |
4483 | if (GET_CODE (op0) == IOR |
4484 | && (rtx_equal_p (XEXP (op0, 0), op1) | |
4485 | || rtx_equal_p (XEXP (op0, 1), op1)) | |
4486 | && ! side_effects_p (XEXP (op0, 0)) | |
4487 | && ! side_effects_p (XEXP (op0, 1))) | |
4488 | return op1; | |
230d793d | 4489 | |
d0ab8cd3 | 4490 | /* In the following group of tests (and those in case IOR below), |
230d793d RS |
4491 | we start with some combination of logical operations and apply |
4492 | the distributive law followed by the inverse distributive law. | |
4493 | Most of the time, this results in no change. However, if some of | |
4494 | the operands are the same or inverses of each other, simplifications | |
4495 | will result. | |
4496 | ||
4497 | For example, (and (ior A B) (not B)) can occur as the result of | |
4498 | expanding a bit field assignment. When we apply the distributive | |
4499 | law to this, we get (ior (and (A (not B))) (and (B (not B)))), | |
8079805d | 4500 | which then simplifies to (and (A (not B))). |
230d793d | 4501 | |
8079805d | 4502 | If we have (and (ior A B) C), apply the distributive law and then |
230d793d RS |
4503 | the inverse distributive law to see if things simplify. */ |
4504 | ||
8079805d | 4505 | if (GET_CODE (op0) == IOR || GET_CODE (op0) == XOR) |
230d793d RS |
4506 | { |
4507 | x = apply_distributive_law | |
8079805d RK |
4508 | (gen_binary (GET_CODE (op0), mode, |
4509 | gen_binary (AND, mode, XEXP (op0, 0), op1), | |
4510 | gen_binary (AND, mode, XEXP (op0, 1), op1))); | |
230d793d | 4511 | if (GET_CODE (x) != AND) |
8079805d | 4512 | return x; |
230d793d RS |
4513 | } |
4514 | ||
8079805d RK |
4515 | if (GET_CODE (op1) == IOR || GET_CODE (op1) == XOR) |
4516 | return apply_distributive_law | |
4517 | (gen_binary (GET_CODE (op1), mode, | |
4518 | gen_binary (AND, mode, XEXP (op1, 0), op0), | |
4519 | gen_binary (AND, mode, XEXP (op1, 1), op0))); | |
230d793d RS |
4520 | |
4521 | /* Similarly, taking advantage of the fact that | |
4522 | (and (not A) (xor B C)) == (xor (ior A B) (ior A C)) */ | |
4523 | ||
8079805d RK |
4524 | if (GET_CODE (op0) == NOT && GET_CODE (op1) == XOR) |
4525 | return apply_distributive_law | |
4526 | (gen_binary (XOR, mode, | |
4527 | gen_binary (IOR, mode, XEXP (op0, 0), XEXP (op1, 0)), | |
4528 | gen_binary (IOR, mode, XEXP (op0, 0), XEXP (op1, 1)))); | |
230d793d | 4529 | |
8079805d RK |
4530 | else if (GET_CODE (op1) == NOT && GET_CODE (op0) == XOR) |
4531 | return apply_distributive_law | |
4532 | (gen_binary (XOR, mode, | |
4533 | gen_binary (IOR, mode, XEXP (op1, 0), XEXP (op0, 0)), | |
4534 | gen_binary (IOR, mode, XEXP (op1, 0), XEXP (op0, 1)))); | |
230d793d RS |
4535 | break; |
4536 | ||
4537 | case IOR: | |
951553af | 4538 | /* (ior A C) is C if all bits of A that might be nonzero are on in C. */ |
8079805d | 4539 | if (GET_CODE (op1) == CONST_INT |
ac49a949 | 4540 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
8079805d RK |
4541 | && (nonzero_bits (op0, mode) & ~ INTVAL (op1)) == 0) |
4542 | return op1; | |
d0ab8cd3 | 4543 | |
230d793d | 4544 | /* Convert (A & B) | A to A. */ |
8079805d RK |
4545 | if (GET_CODE (op0) == AND |
4546 | && (rtx_equal_p (XEXP (op0, 0), op1) | |
4547 | || rtx_equal_p (XEXP (op0, 1), op1)) | |
4548 | && ! side_effects_p (XEXP (op0, 0)) | |
4549 | && ! side_effects_p (XEXP (op0, 1))) | |
4550 | return op1; | |
230d793d RS |
4551 | |
4552 | /* If we have (ior (and A B) C), apply the distributive law and then | |
4553 | the inverse distributive law to see if things simplify. */ | |
4554 | ||
8079805d | 4555 | if (GET_CODE (op0) == AND) |
230d793d RS |
4556 | { |
4557 | x = apply_distributive_law | |
4558 | (gen_binary (AND, mode, | |
8079805d RK |
4559 | gen_binary (IOR, mode, XEXP (op0, 0), op1), |
4560 | gen_binary (IOR, mode, XEXP (op0, 1), op1))); | |
230d793d RS |
4561 | |
4562 | if (GET_CODE (x) != IOR) | |
8079805d | 4563 | return x; |
230d793d RS |
4564 | } |
4565 | ||
8079805d | 4566 | if (GET_CODE (op1) == AND) |
230d793d RS |
4567 | { |
4568 | x = apply_distributive_law | |
4569 | (gen_binary (AND, mode, | |
8079805d RK |
4570 | gen_binary (IOR, mode, XEXP (op1, 0), op0), |
4571 | gen_binary (IOR, mode, XEXP (op1, 1), op0))); | |
230d793d RS |
4572 | |
4573 | if (GET_CODE (x) != IOR) | |
8079805d | 4574 | return x; |
230d793d RS |
4575 | } |
4576 | ||
4577 | /* Convert (ior (ashift A CX) (lshiftrt A CY)) where CX+CY equals the | |
4578 | mode size to (rotate A CX). */ | |
4579 | ||
8079805d RK |
4580 | if (((GET_CODE (op0) == ASHIFT && GET_CODE (op1) == LSHIFTRT) |
4581 | || (GET_CODE (op1) == ASHIFT && GET_CODE (op0) == LSHIFTRT)) | |
4582 | && rtx_equal_p (XEXP (op0, 0), XEXP (op1, 0)) | |
4583 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
4584 | && GET_CODE (XEXP (op1, 1)) == CONST_INT | |
4585 | && (INTVAL (XEXP (op0, 1)) + INTVAL (XEXP (op1, 1)) | |
230d793d | 4586 | == GET_MODE_BITSIZE (mode))) |
8079805d RK |
4587 | return gen_rtx (ROTATE, mode, XEXP (op0, 0), |
4588 | (GET_CODE (op0) == ASHIFT | |
4589 | ? XEXP (op0, 1) : XEXP (op1, 1))); | |
230d793d | 4590 | |
71923da7 RK |
4591 | /* If OP0 is (ashiftrt (plus ...) C), it might actually be |
4592 | a (sign_extend (plus ...)). If so, OP1 is a CONST_INT, and the PLUS | |
4593 | does not affect any of the bits in OP1, it can really be done | |
4594 | as a PLUS and we can associate. We do this by seeing if OP1 | |
4595 | can be safely shifted left C bits. */ | |
4596 | if (GET_CODE (op1) == CONST_INT && GET_CODE (op0) == ASHIFTRT | |
4597 | && GET_CODE (XEXP (op0, 0)) == PLUS | |
4598 | && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT | |
4599 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
4600 | && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT) | |
4601 | { | |
4602 | int count = INTVAL (XEXP (op0, 1)); | |
4603 | HOST_WIDE_INT mask = INTVAL (op1) << count; | |
4604 | ||
4605 | if (mask >> count == INTVAL (op1) | |
4606 | && (mask & nonzero_bits (XEXP (op0, 0), mode)) == 0) | |
4607 | { | |
4608 | SUBST (XEXP (XEXP (op0, 0), 1), | |
4609 | GEN_INT (INTVAL (XEXP (XEXP (op0, 0), 1)) | mask)); | |
4610 | return op0; | |
4611 | } | |
4612 | } | |
230d793d RS |
4613 | break; |
4614 | ||
4615 | case XOR: | |
4616 | /* Convert (XOR (NOT x) (NOT y)) to (XOR x y). | |
4617 | Also convert (XOR (NOT x) y) to (NOT (XOR x y)), similarly for | |
4618 | (NOT y). */ | |
4619 | { | |
4620 | int num_negated = 0; | |
230d793d | 4621 | |
8079805d RK |
4622 | if (GET_CODE (op0) == NOT) |
4623 | num_negated++, op0 = XEXP (op0, 0); | |
4624 | if (GET_CODE (op1) == NOT) | |
4625 | num_negated++, op1 = XEXP (op1, 0); | |
230d793d RS |
4626 | |
4627 | if (num_negated == 2) | |
4628 | { | |
8079805d RK |
4629 | SUBST (XEXP (x, 0), op0); |
4630 | SUBST (XEXP (x, 1), op1); | |
230d793d RS |
4631 | } |
4632 | else if (num_negated == 1) | |
0c1c8ea6 | 4633 | return gen_unary (NOT, mode, mode, gen_binary (XOR, mode, op0, op1)); |
230d793d RS |
4634 | } |
4635 | ||
4636 | /* Convert (xor (and A B) B) to (and (not A) B). The latter may | |
4637 | correspond to a machine insn or result in further simplifications | |
4638 | if B is a constant. */ | |
4639 | ||
8079805d RK |
4640 | if (GET_CODE (op0) == AND |
4641 | && rtx_equal_p (XEXP (op0, 1), op1) | |
4642 | && ! side_effects_p (op1)) | |
0c1c8ea6 RK |
4643 | return gen_binary (AND, mode, |
4644 | gen_unary (NOT, mode, mode, XEXP (op0, 0)), | |
8079805d | 4645 | op1); |
230d793d | 4646 | |
8079805d RK |
4647 | else if (GET_CODE (op0) == AND |
4648 | && rtx_equal_p (XEXP (op0, 0), op1) | |
4649 | && ! side_effects_p (op1)) | |
0c1c8ea6 RK |
4650 | return gen_binary (AND, mode, |
4651 | gen_unary (NOT, mode, mode, XEXP (op0, 1)), | |
8079805d | 4652 | op1); |
230d793d RS |
4653 | |
4654 | #if STORE_FLAG_VALUE == 1 | |
4655 | /* (xor (comparison foo bar) (const_int 1)) can become the reversed | |
4656 | comparison. */ | |
8079805d RK |
4657 | if (op1 == const1_rtx |
4658 | && GET_RTX_CLASS (GET_CODE (op0)) == '<' | |
4659 | && reversible_comparison_p (op0)) | |
4660 | return gen_rtx_combine (reverse_condition (GET_CODE (op0)), | |
4661 | mode, XEXP (op0, 0), XEXP (op0, 1)); | |
500c518b RK |
4662 | |
4663 | /* (lshiftrt foo C) where C is the number of bits in FOO minus 1 | |
4664 | is (lt foo (const_int 0)), so we can perform the above | |
4665 | simplification. */ | |
4666 | ||
8079805d RK |
4667 | if (op1 == const1_rtx |
4668 | && GET_CODE (op0) == LSHIFTRT | |
4669 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
4670 | && INTVAL (XEXP (op0, 1)) == GET_MODE_BITSIZE (mode) - 1) | |
4671 | return gen_rtx_combine (GE, mode, XEXP (op0, 0), const0_rtx); | |
230d793d RS |
4672 | #endif |
4673 | ||
4674 | /* (xor (comparison foo bar) (const_int sign-bit)) | |
4675 | when STORE_FLAG_VALUE is the sign bit. */ | |
5f4f0e22 CH |
4676 | if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
4677 | && (STORE_FLAG_VALUE | |
4678 | == (HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)) | |
8079805d RK |
4679 | && op1 == const_true_rtx |
4680 | && GET_RTX_CLASS (GET_CODE (op0)) == '<' | |
4681 | && reversible_comparison_p (op0)) | |
4682 | return gen_rtx_combine (reverse_condition (GET_CODE (op0)), | |
4683 | mode, XEXP (op0, 0), XEXP (op0, 1)); | |
230d793d RS |
4684 | break; |
4685 | } | |
4686 | ||
4687 | return x; | |
4688 | } | |
4689 | \f | |
4690 | /* We consider ZERO_EXTRACT, SIGN_EXTRACT, and SIGN_EXTEND as "compound | |
4691 | operations" because they can be replaced with two more basic operations. | |
4692 | ZERO_EXTEND is also considered "compound" because it can be replaced with | |
4693 | an AND operation, which is simpler, though only one operation. | |
4694 | ||
4695 | The function expand_compound_operation is called with an rtx expression | |
4696 | and will convert it to the appropriate shifts and AND operations, | |
4697 | simplifying at each stage. | |
4698 | ||
4699 | The function make_compound_operation is called to convert an expression | |
4700 | consisting of shifts and ANDs into the equivalent compound expression. | |
4701 | It is the inverse of this function, loosely speaking. */ | |
4702 | ||
4703 | static rtx | |
4704 | expand_compound_operation (x) | |
4705 | rtx x; | |
4706 | { | |
4707 | int pos = 0, len; | |
4708 | int unsignedp = 0; | |
4709 | int modewidth; | |
4710 | rtx tem; | |
4711 | ||
4712 | switch (GET_CODE (x)) | |
4713 | { | |
4714 | case ZERO_EXTEND: | |
4715 | unsignedp = 1; | |
4716 | case SIGN_EXTEND: | |
75473182 RS |
4717 | /* We can't necessarily use a const_int for a multiword mode; |
4718 | it depends on implicitly extending the value. | |
4719 | Since we don't know the right way to extend it, | |
4720 | we can't tell whether the implicit way is right. | |
4721 | ||
4722 | Even for a mode that is no wider than a const_int, | |
4723 | we can't win, because we need to sign extend one of its bits through | |
4724 | the rest of it, and we don't know which bit. */ | |
230d793d | 4725 | if (GET_CODE (XEXP (x, 0)) == CONST_INT) |
75473182 | 4726 | return x; |
230d793d | 4727 | |
8079805d RK |
4728 | /* Return if (subreg:MODE FROM 0) is not a safe replacement for |
4729 | (zero_extend:MODE FROM) or (sign_extend:MODE FROM). It is for any MEM | |
4730 | because (SUBREG (MEM...)) is guaranteed to cause the MEM to be | |
4731 | reloaded. If not for that, MEM's would very rarely be safe. | |
4732 | ||
4733 | Reject MODEs bigger than a word, because we might not be able | |
4734 | to reference a two-register group starting with an arbitrary register | |
4735 | (and currently gen_lowpart might crash for a SUBREG). */ | |
4736 | ||
4737 | if (GET_MODE_SIZE (GET_MODE (XEXP (x, 0))) > UNITS_PER_WORD) | |
230d793d RS |
4738 | return x; |
4739 | ||
4740 | len = GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))); | |
4741 | /* If the inner object has VOIDmode (the only way this can happen | |
4742 | is if it is a ASM_OPERANDS), we can't do anything since we don't | |
4743 | know how much masking to do. */ | |
4744 | if (len == 0) | |
4745 | return x; | |
4746 | ||
4747 | break; | |
4748 | ||
4749 | case ZERO_EXTRACT: | |
4750 | unsignedp = 1; | |
4751 | case SIGN_EXTRACT: | |
4752 | /* If the operand is a CLOBBER, just return it. */ | |
4753 | if (GET_CODE (XEXP (x, 0)) == CLOBBER) | |
4754 | return XEXP (x, 0); | |
4755 | ||
4756 | if (GET_CODE (XEXP (x, 1)) != CONST_INT | |
4757 | || GET_CODE (XEXP (x, 2)) != CONST_INT | |
4758 | || GET_MODE (XEXP (x, 0)) == VOIDmode) | |
4759 | return x; | |
4760 | ||
4761 | len = INTVAL (XEXP (x, 1)); | |
4762 | pos = INTVAL (XEXP (x, 2)); | |
4763 | ||
4764 | /* If this goes outside the object being extracted, replace the object | |
4765 | with a (use (mem ...)) construct that only combine understands | |
4766 | and is used only for this purpose. */ | |
4767 | if (len + pos > GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))) | |
4768 | SUBST (XEXP (x, 0), gen_rtx (USE, GET_MODE (x), XEXP (x, 0))); | |
4769 | ||
4770 | #if BITS_BIG_ENDIAN | |
4771 | pos = GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - len - pos; | |
4772 | #endif | |
4773 | break; | |
4774 | ||
4775 | default: | |
4776 | return x; | |
4777 | } | |
4778 | ||
4779 | /* If we reach here, we want to return a pair of shifts. The inner | |
4780 | shift is a left shift of BITSIZE - POS - LEN bits. The outer | |
4781 | shift is a right shift of BITSIZE - LEN bits. It is arithmetic or | |
4782 | logical depending on the value of UNSIGNEDP. | |
4783 | ||
4784 | If this was a ZERO_EXTEND or ZERO_EXTRACT, this pair of shifts will be | |
4785 | converted into an AND of a shift. | |
4786 | ||
4787 | We must check for the case where the left shift would have a negative | |
4788 | count. This can happen in a case like (x >> 31) & 255 on machines | |
4789 | that can't shift by a constant. On those machines, we would first | |
4790 | combine the shift with the AND to produce a variable-position | |
4791 | extraction. Then the constant of 31 would be substituted in to produce | |
4792 | a such a position. */ | |
4793 | ||
4794 | modewidth = GET_MODE_BITSIZE (GET_MODE (x)); | |
4795 | if (modewidth >= pos - len) | |
5f4f0e22 | 4796 | tem = simplify_shift_const (NULL_RTX, unsignedp ? LSHIFTRT : ASHIFTRT, |
230d793d | 4797 | GET_MODE (x), |
5f4f0e22 CH |
4798 | simplify_shift_const (NULL_RTX, ASHIFT, |
4799 | GET_MODE (x), | |
230d793d RS |
4800 | XEXP (x, 0), |
4801 | modewidth - pos - len), | |
4802 | modewidth - len); | |
4803 | ||
5f4f0e22 CH |
4804 | else if (unsignedp && len < HOST_BITS_PER_WIDE_INT) |
4805 | tem = simplify_and_const_int (NULL_RTX, GET_MODE (x), | |
4806 | simplify_shift_const (NULL_RTX, LSHIFTRT, | |
230d793d RS |
4807 | GET_MODE (x), |
4808 | XEXP (x, 0), pos), | |
5f4f0e22 | 4809 | ((HOST_WIDE_INT) 1 << len) - 1); |
230d793d RS |
4810 | else |
4811 | /* Any other cases we can't handle. */ | |
4812 | return x; | |
4813 | ||
4814 | ||
4815 | /* If we couldn't do this for some reason, return the original | |
4816 | expression. */ | |
4817 | if (GET_CODE (tem) == CLOBBER) | |
4818 | return x; | |
4819 | ||
4820 | return tem; | |
4821 | } | |
4822 | \f | |
4823 | /* X is a SET which contains an assignment of one object into | |
4824 | a part of another (such as a bit-field assignment, STRICT_LOW_PART, | |
4825 | or certain SUBREGS). If possible, convert it into a series of | |
4826 | logical operations. | |
4827 | ||
4828 | We half-heartedly support variable positions, but do not at all | |
4829 | support variable lengths. */ | |
4830 | ||
4831 | static rtx | |
4832 | expand_field_assignment (x) | |
4833 | rtx x; | |
4834 | { | |
4835 | rtx inner; | |
4836 | rtx pos; /* Always counts from low bit. */ | |
4837 | int len; | |
4838 | rtx mask; | |
4839 | enum machine_mode compute_mode; | |
4840 | ||
4841 | /* Loop until we find something we can't simplify. */ | |
4842 | while (1) | |
4843 | { | |
4844 | if (GET_CODE (SET_DEST (x)) == STRICT_LOW_PART | |
4845 | && GET_CODE (XEXP (SET_DEST (x), 0)) == SUBREG) | |
4846 | { | |
4847 | inner = SUBREG_REG (XEXP (SET_DEST (x), 0)); | |
4848 | len = GET_MODE_BITSIZE (GET_MODE (XEXP (SET_DEST (x), 0))); | |
4849 | pos = const0_rtx; | |
4850 | } | |
4851 | else if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT | |
4852 | && GET_CODE (XEXP (SET_DEST (x), 1)) == CONST_INT) | |
4853 | { | |
4854 | inner = XEXP (SET_DEST (x), 0); | |
4855 | len = INTVAL (XEXP (SET_DEST (x), 1)); | |
4856 | pos = XEXP (SET_DEST (x), 2); | |
4857 | ||
4858 | /* If the position is constant and spans the width of INNER, | |
4859 | surround INNER with a USE to indicate this. */ | |
4860 | if (GET_CODE (pos) == CONST_INT | |
4861 | && INTVAL (pos) + len > GET_MODE_BITSIZE (GET_MODE (inner))) | |
4862 | inner = gen_rtx (USE, GET_MODE (SET_DEST (x)), inner); | |
4863 | ||
4864 | #if BITS_BIG_ENDIAN | |
4865 | if (GET_CODE (pos) == CONST_INT) | |
5f4f0e22 CH |
4866 | pos = GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner)) - len |
4867 | - INTVAL (pos)); | |
230d793d RS |
4868 | else if (GET_CODE (pos) == MINUS |
4869 | && GET_CODE (XEXP (pos, 1)) == CONST_INT | |
4870 | && (INTVAL (XEXP (pos, 1)) | |
4871 | == GET_MODE_BITSIZE (GET_MODE (inner)) - len)) | |
4872 | /* If position is ADJUST - X, new position is X. */ | |
4873 | pos = XEXP (pos, 0); | |
4874 | else | |
4875 | pos = gen_binary (MINUS, GET_MODE (pos), | |
5f4f0e22 CH |
4876 | GEN_INT (GET_MODE_BITSIZE (GET_MODE (inner)) |
4877 | - len), | |
4878 | pos); | |
230d793d RS |
4879 | #endif |
4880 | } | |
4881 | ||
4882 | /* A SUBREG between two modes that occupy the same numbers of words | |
4883 | can be done by moving the SUBREG to the source. */ | |
4884 | else if (GET_CODE (SET_DEST (x)) == SUBREG | |
4885 | && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) | |
4886 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
4887 | == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) | |
4888 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))) | |
4889 | { | |
4890 | x = gen_rtx (SET, VOIDmode, SUBREG_REG (SET_DEST (x)), | |
4891 | gen_lowpart_for_combine (GET_MODE (SUBREG_REG (SET_DEST (x))), | |
4892 | SET_SRC (x))); | |
4893 | continue; | |
4894 | } | |
4895 | else | |
4896 | break; | |
4897 | ||
4898 | while (GET_CODE (inner) == SUBREG && subreg_lowpart_p (inner)) | |
4899 | inner = SUBREG_REG (inner); | |
4900 | ||
4901 | compute_mode = GET_MODE (inner); | |
4902 | ||
4903 | /* Compute a mask of LEN bits, if we can do this on the host machine. */ | |
5f4f0e22 CH |
4904 | if (len < HOST_BITS_PER_WIDE_INT) |
4905 | mask = GEN_INT (((HOST_WIDE_INT) 1 << len) - 1); | |
230d793d RS |
4906 | else |
4907 | break; | |
4908 | ||
4909 | /* Now compute the equivalent expression. Make a copy of INNER | |
4910 | for the SET_DEST in case it is a MEM into which we will substitute; | |
4911 | we don't want shared RTL in that case. */ | |
4912 | x = gen_rtx (SET, VOIDmode, copy_rtx (inner), | |
4913 | gen_binary (IOR, compute_mode, | |
4914 | gen_binary (AND, compute_mode, | |
4915 | gen_unary (NOT, compute_mode, | |
0c1c8ea6 | 4916 | compute_mode, |
230d793d RS |
4917 | gen_binary (ASHIFT, |
4918 | compute_mode, | |
4919 | mask, pos)), | |
4920 | inner), | |
4921 | gen_binary (ASHIFT, compute_mode, | |
4922 | gen_binary (AND, compute_mode, | |
4923 | gen_lowpart_for_combine | |
4924 | (compute_mode, | |
4925 | SET_SRC (x)), | |
4926 | mask), | |
4927 | pos))); | |
4928 | } | |
4929 | ||
4930 | return x; | |
4931 | } | |
4932 | \f | |
8999a12e RK |
4933 | /* Return an RTX for a reference to LEN bits of INNER. If POS_RTX is nonzero, |
4934 | it is an RTX that represents a variable starting position; otherwise, | |
4935 | POS is the (constant) starting bit position (counted from the LSB). | |
230d793d RS |
4936 | |
4937 | INNER may be a USE. This will occur when we started with a bitfield | |
4938 | that went outside the boundary of the object in memory, which is | |
4939 | allowed on most machines. To isolate this case, we produce a USE | |
4940 | whose mode is wide enough and surround the MEM with it. The only | |
4941 | code that understands the USE is this routine. If it is not removed, | |
4942 | it will cause the resulting insn not to match. | |
4943 | ||
4944 | UNSIGNEDP is non-zero for an unsigned reference and zero for a | |
4945 | signed reference. | |
4946 | ||
4947 | IN_DEST is non-zero if this is a reference in the destination of a | |
4948 | SET. This is used when a ZERO_ or SIGN_EXTRACT isn't needed. If non-zero, | |
4949 | a STRICT_LOW_PART will be used, if zero, ZERO_EXTEND or SIGN_EXTEND will | |
4950 | be used. | |
4951 | ||
4952 | IN_COMPARE is non-zero if we are in a COMPARE. This means that a | |
4953 | ZERO_EXTRACT should be built even for bits starting at bit 0. | |
4954 | ||
4955 | MODE is the desired mode of the result (if IN_DEST == 0). */ | |
4956 | ||
4957 | static rtx | |
4958 | make_extraction (mode, inner, pos, pos_rtx, len, | |
4959 | unsignedp, in_dest, in_compare) | |
4960 | enum machine_mode mode; | |
4961 | rtx inner; | |
4962 | int pos; | |
4963 | rtx pos_rtx; | |
4964 | int len; | |
4965 | int unsignedp; | |
4966 | int in_dest, in_compare; | |
4967 | { | |
94b4b17a RS |
4968 | /* This mode describes the size of the storage area |
4969 | to fetch the overall value from. Within that, we | |
4970 | ignore the POS lowest bits, etc. */ | |
230d793d RS |
4971 | enum machine_mode is_mode = GET_MODE (inner); |
4972 | enum machine_mode inner_mode; | |
4973 | enum machine_mode wanted_mem_mode = byte_mode; | |
4974 | enum machine_mode pos_mode = word_mode; | |
4975 | enum machine_mode extraction_mode = word_mode; | |
4976 | enum machine_mode tmode = mode_for_size (len, MODE_INT, 1); | |
4977 | int spans_byte = 0; | |
4978 | rtx new = 0; | |
8999a12e | 4979 | rtx orig_pos_rtx = pos_rtx; |
6139ff20 | 4980 | int orig_pos; |
230d793d RS |
4981 | |
4982 | /* Get some information about INNER and get the innermost object. */ | |
4983 | if (GET_CODE (inner) == USE) | |
94b4b17a | 4984 | /* (use:SI (mem:QI foo)) stands for (mem:SI foo). */ |
230d793d RS |
4985 | /* We don't need to adjust the position because we set up the USE |
4986 | to pretend that it was a full-word object. */ | |
4987 | spans_byte = 1, inner = XEXP (inner, 0); | |
4988 | else if (GET_CODE (inner) == SUBREG && subreg_lowpart_p (inner)) | |
94b4b17a RS |
4989 | { |
4990 | /* If going from (subreg:SI (mem:QI ...)) to (mem:QI ...), | |
4991 | consider just the QI as the memory to extract from. | |
4992 | The subreg adds or removes high bits; its mode is | |
4993 | irrelevant to the meaning of this extraction, | |
4994 | since POS and LEN count from the lsb. */ | |
4995 | if (GET_CODE (SUBREG_REG (inner)) == MEM) | |
4996 | is_mode = GET_MODE (SUBREG_REG (inner)); | |
4997 | inner = SUBREG_REG (inner); | |
4998 | } | |
230d793d RS |
4999 | |
5000 | inner_mode = GET_MODE (inner); | |
5001 | ||
5002 | if (pos_rtx && GET_CODE (pos_rtx) == CONST_INT) | |
8999a12e | 5003 | pos = INTVAL (pos_rtx), pos_rtx = 0; |
230d793d RS |
5004 | |
5005 | /* See if this can be done without an extraction. We never can if the | |
5006 | width of the field is not the same as that of some integer mode. For | |
5007 | registers, we can only avoid the extraction if the position is at the | |
5008 | low-order bit and this is either not in the destination or we have the | |
5009 | appropriate STRICT_LOW_PART operation available. | |
5010 | ||
5011 | For MEM, we can avoid an extract if the field starts on an appropriate | |
5012 | boundary and we can change the mode of the memory reference. However, | |
5013 | we cannot directly access the MEM if we have a USE and the underlying | |
5014 | MEM is not TMODE. This combination means that MEM was being used in a | |
5015 | context where bits outside its mode were being referenced; that is only | |
5016 | valid in bit-field insns. */ | |
5017 | ||
5018 | if (tmode != BLKmode | |
5019 | && ! (spans_byte && inner_mode != tmode) | |
8999a12e | 5020 | && ((pos_rtx == 0 && pos == 0 && GET_CODE (inner) != MEM |
230d793d | 5021 | && (! in_dest |
df62f951 RK |
5022 | || (GET_CODE (inner) == REG |
5023 | && (movstrict_optab->handlers[(int) tmode].insn_code | |
5024 | != CODE_FOR_nothing)))) | |
8999a12e | 5025 | || (GET_CODE (inner) == MEM && pos_rtx == 0 |
dfbe1b2f RK |
5026 | && (pos |
5027 | % (STRICT_ALIGNMENT ? GET_MODE_ALIGNMENT (tmode) | |
5028 | : BITS_PER_UNIT)) == 0 | |
230d793d RS |
5029 | /* We can't do this if we are widening INNER_MODE (it |
5030 | may not be aligned, for one thing). */ | |
5031 | && GET_MODE_BITSIZE (inner_mode) >= GET_MODE_BITSIZE (tmode) | |
5032 | && (inner_mode == tmode | |
5033 | || (! mode_dependent_address_p (XEXP (inner, 0)) | |
5034 | && ! MEM_VOLATILE_P (inner)))))) | |
5035 | { | |
230d793d RS |
5036 | /* If INNER is a MEM, make a new MEM that encompasses just the desired |
5037 | field. If the original and current mode are the same, we need not | |
5038 | adjust the offset. Otherwise, we do if bytes big endian. | |
5039 | ||
5040 | If INNER is not a MEM, get a piece consisting of the just the field | |
df62f951 | 5041 | of interest (in this case POS must be 0). */ |
230d793d RS |
5042 | |
5043 | if (GET_CODE (inner) == MEM) | |
5044 | { | |
94b4b17a RS |
5045 | int offset; |
5046 | /* POS counts from lsb, but make OFFSET count in memory order. */ | |
5047 | if (BYTES_BIG_ENDIAN) | |
5048 | offset = (GET_MODE_BITSIZE (is_mode) - len - pos) / BITS_PER_UNIT; | |
5049 | else | |
5050 | offset = pos / BITS_PER_UNIT; | |
230d793d RS |
5051 | |
5052 | new = gen_rtx (MEM, tmode, plus_constant (XEXP (inner, 0), offset)); | |
5053 | RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (inner); | |
5054 | MEM_VOLATILE_P (new) = MEM_VOLATILE_P (inner); | |
5055 | MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (inner); | |
5056 | } | |
df62f951 | 5057 | else if (GET_CODE (inner) == REG) |
c0d3ac4d RK |
5058 | { |
5059 | /* We can't call gen_lowpart_for_combine here since we always want | |
5060 | a SUBREG and it would sometimes return a new hard register. */ | |
5061 | if (tmode != inner_mode) | |
5062 | new = gen_rtx (SUBREG, tmode, inner, | |
5063 | (WORDS_BIG_ENDIAN | |
5064 | && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD | |
5065 | ? ((GET_MODE_SIZE (inner_mode) | |
5066 | - GET_MODE_SIZE (tmode)) | |
5067 | / UNITS_PER_WORD) | |
5068 | : 0)); | |
5069 | else | |
5070 | new = inner; | |
5071 | } | |
230d793d | 5072 | else |
6139ff20 RK |
5073 | new = force_to_mode (inner, tmode, |
5074 | len >= HOST_BITS_PER_WIDE_INT | |
5075 | ? GET_MODE_MASK (tmode) | |
5076 | : ((HOST_WIDE_INT) 1 << len) - 1, | |
e3d616e3 | 5077 | NULL_RTX, 0); |
230d793d RS |
5078 | |
5079 | /* If this extraction is going into the destination of a SET, | |
5080 | make a STRICT_LOW_PART unless we made a MEM. */ | |
5081 | ||
5082 | if (in_dest) | |
5083 | return (GET_CODE (new) == MEM ? new | |
77fa0940 RK |
5084 | : (GET_CODE (new) != SUBREG |
5085 | ? gen_rtx (CLOBBER, tmode, const0_rtx) | |
5086 | : gen_rtx_combine (STRICT_LOW_PART, VOIDmode, new))); | |
230d793d RS |
5087 | |
5088 | /* Otherwise, sign- or zero-extend unless we already are in the | |
5089 | proper mode. */ | |
5090 | ||
5091 | return (mode == tmode ? new | |
5092 | : gen_rtx_combine (unsignedp ? ZERO_EXTEND : SIGN_EXTEND, | |
5093 | mode, new)); | |
5094 | } | |
5095 | ||
cc471082 RS |
5096 | /* Unless this is a COMPARE or we have a funny memory reference, |
5097 | don't do anything with zero-extending field extracts starting at | |
5098 | the low-order bit since they are simple AND operations. */ | |
8999a12e RK |
5099 | if (pos_rtx == 0 && pos == 0 && ! in_dest |
5100 | && ! in_compare && ! spans_byte && unsignedp) | |
230d793d RS |
5101 | return 0; |
5102 | ||
e7373556 RK |
5103 | /* Unless we are allowed to span bytes, reject this if we would be |
5104 | spanning bytes or if the position is not a constant and the length | |
5105 | is not 1. In all other cases, we would only be going outside | |
5106 | out object in cases when an original shift would have been | |
5107 | undefined. */ | |
5108 | if (! spans_byte | |
5109 | && ((pos_rtx == 0 && pos + len > GET_MODE_BITSIZE (is_mode)) | |
5110 | || (pos_rtx != 0 && len != 1))) | |
5111 | return 0; | |
5112 | ||
230d793d RS |
5113 | /* Get the mode to use should INNER be a MEM, the mode for the position, |
5114 | and the mode for the result. */ | |
5115 | #ifdef HAVE_insv | |
5116 | if (in_dest) | |
5117 | { | |
5118 | wanted_mem_mode = insn_operand_mode[(int) CODE_FOR_insv][0]; | |
5119 | pos_mode = insn_operand_mode[(int) CODE_FOR_insv][2]; | |
5120 | extraction_mode = insn_operand_mode[(int) CODE_FOR_insv][3]; | |
5121 | } | |
5122 | #endif | |
5123 | ||
5124 | #ifdef HAVE_extzv | |
5125 | if (! in_dest && unsignedp) | |
5126 | { | |
5127 | wanted_mem_mode = insn_operand_mode[(int) CODE_FOR_extzv][1]; | |
5128 | pos_mode = insn_operand_mode[(int) CODE_FOR_extzv][3]; | |
5129 | extraction_mode = insn_operand_mode[(int) CODE_FOR_extzv][0]; | |
5130 | } | |
5131 | #endif | |
5132 | ||
5133 | #ifdef HAVE_extv | |
5134 | if (! in_dest && ! unsignedp) | |
5135 | { | |
5136 | wanted_mem_mode = insn_operand_mode[(int) CODE_FOR_extv][1]; | |
5137 | pos_mode = insn_operand_mode[(int) CODE_FOR_extv][3]; | |
5138 | extraction_mode = insn_operand_mode[(int) CODE_FOR_extv][0]; | |
5139 | } | |
5140 | #endif | |
5141 | ||
5142 | /* Never narrow an object, since that might not be safe. */ | |
5143 | ||
5144 | if (mode != VOIDmode | |
5145 | && GET_MODE_SIZE (extraction_mode) < GET_MODE_SIZE (mode)) | |
5146 | extraction_mode = mode; | |
5147 | ||
5148 | if (pos_rtx && GET_MODE (pos_rtx) != VOIDmode | |
5149 | && GET_MODE_SIZE (pos_mode) < GET_MODE_SIZE (GET_MODE (pos_rtx))) | |
5150 | pos_mode = GET_MODE (pos_rtx); | |
5151 | ||
5152 | /* If this is not from memory or we have to change the mode of memory and | |
5153 | cannot, the desired mode is EXTRACTION_MODE. */ | |
5154 | if (GET_CODE (inner) != MEM | |
5155 | || (inner_mode != wanted_mem_mode | |
5156 | && (mode_dependent_address_p (XEXP (inner, 0)) | |
5157 | || MEM_VOLATILE_P (inner)))) | |
5158 | wanted_mem_mode = extraction_mode; | |
5159 | ||
6139ff20 RK |
5160 | orig_pos = pos; |
5161 | ||
230d793d RS |
5162 | #if BITS_BIG_ENDIAN |
5163 | /* If position is constant, compute new position. Otherwise, build | |
5164 | subtraction. */ | |
8999a12e | 5165 | if (pos_rtx == 0) |
230d793d RS |
5166 | pos = (MAX (GET_MODE_BITSIZE (is_mode), GET_MODE_BITSIZE (wanted_mem_mode)) |
5167 | - len - pos); | |
5168 | else | |
5169 | pos_rtx | |
5170 | = gen_rtx_combine (MINUS, GET_MODE (pos_rtx), | |
5f4f0e22 CH |
5171 | GEN_INT (MAX (GET_MODE_BITSIZE (is_mode), |
5172 | GET_MODE_BITSIZE (wanted_mem_mode)) | |
5173 | - len), | |
5174 | pos_rtx); | |
230d793d RS |
5175 | #endif |
5176 | ||
5177 | /* If INNER has a wider mode, make it smaller. If this is a constant | |
5178 | extract, try to adjust the byte to point to the byte containing | |
5179 | the value. */ | |
5180 | if (wanted_mem_mode != VOIDmode | |
5181 | && GET_MODE_SIZE (wanted_mem_mode) < GET_MODE_SIZE (is_mode) | |
5182 | && ((GET_CODE (inner) == MEM | |
5183 | && (inner_mode == wanted_mem_mode | |
5184 | || (! mode_dependent_address_p (XEXP (inner, 0)) | |
5185 | && ! MEM_VOLATILE_P (inner)))))) | |
5186 | { | |
5187 | int offset = 0; | |
5188 | ||
5189 | /* The computations below will be correct if the machine is big | |
5190 | endian in both bits and bytes or little endian in bits and bytes. | |
5191 | If it is mixed, we must adjust. */ | |
5192 | ||
230d793d RS |
5193 | /* If bytes are big endian and we had a paradoxical SUBREG, we must |
5194 | adjust OFFSET to compensate. */ | |
5195 | #if BYTES_BIG_ENDIAN | |
5196 | if (! spans_byte | |
5197 | && GET_MODE_SIZE (inner_mode) < GET_MODE_SIZE (is_mode)) | |
5198 | offset -= GET_MODE_SIZE (is_mode) - GET_MODE_SIZE (inner_mode); | |
5199 | #endif | |
5200 | ||
5201 | /* If this is a constant position, we can move to the desired byte. */ | |
8999a12e | 5202 | if (pos_rtx == 0) |
230d793d RS |
5203 | { |
5204 | offset += pos / BITS_PER_UNIT; | |
5205 | pos %= GET_MODE_BITSIZE (wanted_mem_mode); | |
5206 | } | |
5207 | ||
c6b3f1f2 JW |
5208 | #if BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN |
5209 | if (! spans_byte && is_mode != wanted_mem_mode) | |
5210 | offset = (GET_MODE_SIZE (is_mode) | |
5211 | - GET_MODE_SIZE (wanted_mem_mode) - offset); | |
5212 | #endif | |
5213 | ||
230d793d RS |
5214 | if (offset != 0 || inner_mode != wanted_mem_mode) |
5215 | { | |
5216 | rtx newmem = gen_rtx (MEM, wanted_mem_mode, | |
5217 | plus_constant (XEXP (inner, 0), offset)); | |
5218 | RTX_UNCHANGING_P (newmem) = RTX_UNCHANGING_P (inner); | |
5219 | MEM_VOLATILE_P (newmem) = MEM_VOLATILE_P (inner); | |
5220 | MEM_IN_STRUCT_P (newmem) = MEM_IN_STRUCT_P (inner); | |
5221 | inner = newmem; | |
5222 | } | |
5223 | } | |
5224 | ||
5225 | /* If INNER is not memory, we can always get it into the proper mode. */ | |
5226 | else if (GET_CODE (inner) != MEM) | |
d0ab8cd3 | 5227 | inner = force_to_mode (inner, extraction_mode, |
6139ff20 RK |
5228 | pos_rtx || len + orig_pos >= HOST_BITS_PER_WIDE_INT |
5229 | ? GET_MODE_MASK (extraction_mode) | |
5230 | : (((HOST_WIDE_INT) 1 << len) - 1) << orig_pos, | |
e3d616e3 | 5231 | NULL_RTX, 0); |
230d793d RS |
5232 | |
5233 | /* Adjust mode of POS_RTX, if needed. If we want a wider mode, we | |
5234 | have to zero extend. Otherwise, we can just use a SUBREG. */ | |
8999a12e | 5235 | if (pos_rtx != 0 |
230d793d RS |
5236 | && GET_MODE_SIZE (pos_mode) > GET_MODE_SIZE (GET_MODE (pos_rtx))) |
5237 | pos_rtx = gen_rtx_combine (ZERO_EXTEND, pos_mode, pos_rtx); | |
8999a12e | 5238 | else if (pos_rtx != 0 |
230d793d RS |
5239 | && GET_MODE_SIZE (pos_mode) < GET_MODE_SIZE (GET_MODE (pos_rtx))) |
5240 | pos_rtx = gen_lowpart_for_combine (pos_mode, pos_rtx); | |
5241 | ||
8999a12e RK |
5242 | /* Make POS_RTX unless we already have it and it is correct. If we don't |
5243 | have a POS_RTX but we do have an ORIG_POS_RTX, the latter must | |
5244 | be a CONST_INT. */ | |
5245 | if (pos_rtx == 0 && orig_pos_rtx != 0 && INTVAL (orig_pos_rtx) == pos) | |
5246 | pos_rtx = orig_pos_rtx; | |
5247 | ||
5248 | else if (pos_rtx == 0) | |
5f4f0e22 | 5249 | pos_rtx = GEN_INT (pos); |
230d793d RS |
5250 | |
5251 | /* Make the required operation. See if we can use existing rtx. */ | |
5252 | new = gen_rtx_combine (unsignedp ? ZERO_EXTRACT : SIGN_EXTRACT, | |
5f4f0e22 | 5253 | extraction_mode, inner, GEN_INT (len), pos_rtx); |
230d793d RS |
5254 | if (! in_dest) |
5255 | new = gen_lowpart_for_combine (mode, new); | |
5256 | ||
5257 | return new; | |
5258 | } | |
5259 | \f | |
71923da7 RK |
5260 | /* See if X contains an ASHIFT of COUNT or more bits that can be commuted |
5261 | with any other operations in X. Return X without that shift if so. */ | |
5262 | ||
5263 | static rtx | |
5264 | extract_left_shift (x, count) | |
5265 | rtx x; | |
5266 | int count; | |
5267 | { | |
5268 | enum rtx_code code = GET_CODE (x); | |
5269 | enum machine_mode mode = GET_MODE (x); | |
5270 | rtx tem; | |
5271 | ||
5272 | switch (code) | |
5273 | { | |
5274 | case ASHIFT: | |
5275 | /* This is the shift itself. If it is wide enough, we will return | |
5276 | either the value being shifted if the shift count is equal to | |
5277 | COUNT or a shift for the difference. */ | |
5278 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
5279 | && INTVAL (XEXP (x, 1)) >= count) | |
5280 | return simplify_shift_const (NULL_RTX, ASHIFT, mode, XEXP (x, 0), | |
5281 | INTVAL (XEXP (x, 1)) - count); | |
5282 | break; | |
5283 | ||
5284 | case NEG: case NOT: | |
5285 | if ((tem = extract_left_shift (XEXP (x, 0), count)) != 0) | |
0c1c8ea6 | 5286 | return gen_unary (code, mode, mode, tem); |
71923da7 RK |
5287 | |
5288 | break; | |
5289 | ||
5290 | case PLUS: case IOR: case XOR: case AND: | |
5291 | /* If we can safely shift this constant and we find the inner shift, | |
5292 | make a new operation. */ | |
5293 | if (GET_CODE (XEXP (x,1)) == CONST_INT | |
5294 | && (INTVAL (XEXP (x, 1)) & (((HOST_WIDE_INT) 1 << count)) - 1) == 0 | |
5295 | && (tem = extract_left_shift (XEXP (x, 0), count)) != 0) | |
5296 | return gen_binary (code, mode, tem, | |
5297 | GEN_INT (INTVAL (XEXP (x, 1)) >> count)); | |
5298 | ||
5299 | break; | |
5300 | } | |
5301 | ||
5302 | return 0; | |
5303 | } | |
5304 | \f | |
230d793d RS |
5305 | /* Look at the expression rooted at X. Look for expressions |
5306 | equivalent to ZERO_EXTRACT, SIGN_EXTRACT, ZERO_EXTEND, SIGN_EXTEND. | |
5307 | Form these expressions. | |
5308 | ||
5309 | Return the new rtx, usually just X. | |
5310 | ||
5311 | Also, for machines like the Vax that don't have logical shift insns, | |
5312 | try to convert logical to arithmetic shift operations in cases where | |
5313 | they are equivalent. This undoes the canonicalizations to logical | |
5314 | shifts done elsewhere. | |
5315 | ||
5316 | We try, as much as possible, to re-use rtl expressions to save memory. | |
5317 | ||
5318 | IN_CODE says what kind of expression we are processing. Normally, it is | |
42495ca0 RK |
5319 | SET. In a memory address (inside a MEM, PLUS or minus, the latter two |
5320 | being kludges), it is MEM. When processing the arguments of a comparison | |
230d793d RS |
5321 | or a COMPARE against zero, it is COMPARE. */ |
5322 | ||
5323 | static rtx | |
5324 | make_compound_operation (x, in_code) | |
5325 | rtx x; | |
5326 | enum rtx_code in_code; | |
5327 | { | |
5328 | enum rtx_code code = GET_CODE (x); | |
5329 | enum machine_mode mode = GET_MODE (x); | |
5330 | int mode_width = GET_MODE_BITSIZE (mode); | |
71923da7 | 5331 | rtx rhs, lhs; |
230d793d | 5332 | enum rtx_code next_code; |
f24ad0e4 | 5333 | int i; |
230d793d | 5334 | rtx new = 0; |
280f58ba | 5335 | rtx tem; |
230d793d RS |
5336 | char *fmt; |
5337 | ||
5338 | /* Select the code to be used in recursive calls. Once we are inside an | |
5339 | address, we stay there. If we have a comparison, set to COMPARE, | |
5340 | but once inside, go back to our default of SET. */ | |
5341 | ||
42495ca0 | 5342 | next_code = (code == MEM || code == PLUS || code == MINUS ? MEM |
230d793d RS |
5343 | : ((code == COMPARE || GET_RTX_CLASS (code) == '<') |
5344 | && XEXP (x, 1) == const0_rtx) ? COMPARE | |
5345 | : in_code == COMPARE ? SET : in_code); | |
5346 | ||
5347 | /* Process depending on the code of this operation. If NEW is set | |
5348 | non-zero, it will be returned. */ | |
5349 | ||
5350 | switch (code) | |
5351 | { | |
5352 | case ASHIFT: | |
230d793d RS |
5353 | /* Convert shifts by constants into multiplications if inside |
5354 | an address. */ | |
5355 | if (in_code == MEM && GET_CODE (XEXP (x, 1)) == CONST_INT | |
5f4f0e22 | 5356 | && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT |
230d793d | 5357 | && INTVAL (XEXP (x, 1)) >= 0) |
280f58ba RK |
5358 | { |
5359 | new = make_compound_operation (XEXP (x, 0), next_code); | |
5360 | new = gen_rtx_combine (MULT, mode, new, | |
5361 | GEN_INT ((HOST_WIDE_INT) 1 | |
5362 | << INTVAL (XEXP (x, 1)))); | |
5363 | } | |
230d793d RS |
5364 | break; |
5365 | ||
5366 | case AND: | |
5367 | /* If the second operand is not a constant, we can't do anything | |
5368 | with it. */ | |
5369 | if (GET_CODE (XEXP (x, 1)) != CONST_INT) | |
5370 | break; | |
5371 | ||
5372 | /* If the constant is a power of two minus one and the first operand | |
5373 | is a logical right shift, make an extraction. */ | |
5374 | if (GET_CODE (XEXP (x, 0)) == LSHIFTRT | |
5375 | && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) | |
280f58ba RK |
5376 | { |
5377 | new = make_compound_operation (XEXP (XEXP (x, 0), 0), next_code); | |
5378 | new = make_extraction (mode, new, 0, XEXP (XEXP (x, 0), 1), i, 1, | |
5379 | 0, in_code == COMPARE); | |
5380 | } | |
dfbe1b2f | 5381 | |
230d793d RS |
5382 | /* Same as previous, but for (subreg (lshiftrt ...)) in first op. */ |
5383 | else if (GET_CODE (XEXP (x, 0)) == SUBREG | |
5384 | && subreg_lowpart_p (XEXP (x, 0)) | |
5385 | && GET_CODE (SUBREG_REG (XEXP (x, 0))) == LSHIFTRT | |
5386 | && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) | |
280f58ba RK |
5387 | { |
5388 | new = make_compound_operation (XEXP (SUBREG_REG (XEXP (x, 0)), 0), | |
5389 | next_code); | |
aadfb062 | 5390 | new = make_extraction (mode, new, 0, |
280f58ba RK |
5391 | XEXP (SUBREG_REG (XEXP (x, 0)), 1), i, 1, |
5392 | 0, in_code == COMPARE); | |
5393 | } | |
45620ed4 | 5394 | /* Same as previous, but for (xor/ior (lshiftrt...) (lshiftrt...)). */ |
c2f9f64e JW |
5395 | else if ((GET_CODE (XEXP (x, 0)) == XOR |
5396 | || GET_CODE (XEXP (x, 0)) == IOR) | |
5397 | && GET_CODE (XEXP (XEXP (x, 0), 0)) == LSHIFTRT | |
5398 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == LSHIFTRT | |
5399 | && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) | |
5400 | { | |
5401 | /* Apply the distributive law, and then try to make extractions. */ | |
5402 | new = gen_rtx_combine (GET_CODE (XEXP (x, 0)), mode, | |
5403 | gen_rtx (AND, mode, XEXP (XEXP (x, 0), 0), | |
5404 | XEXP (x, 1)), | |
5405 | gen_rtx (AND, mode, XEXP (XEXP (x, 0), 1), | |
5406 | XEXP (x, 1))); | |
5407 | new = make_compound_operation (new, in_code); | |
5408 | } | |
a7c99304 RK |
5409 | |
5410 | /* If we are have (and (rotate X C) M) and C is larger than the number | |
5411 | of bits in M, this is an extraction. */ | |
5412 | ||
5413 | else if (GET_CODE (XEXP (x, 0)) == ROTATE | |
5414 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
5415 | && (i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0 | |
5416 | && i <= INTVAL (XEXP (XEXP (x, 0), 1))) | |
280f58ba RK |
5417 | { |
5418 | new = make_compound_operation (XEXP (XEXP (x, 0), 0), next_code); | |
5419 | new = make_extraction (mode, new, | |
5420 | (GET_MODE_BITSIZE (mode) | |
5421 | - INTVAL (XEXP (XEXP (x, 0), 1))), | |
5422 | NULL_RTX, i, 1, 0, in_code == COMPARE); | |
5423 | } | |
a7c99304 RK |
5424 | |
5425 | /* On machines without logical shifts, if the operand of the AND is | |
230d793d RS |
5426 | a logical shift and our mask turns off all the propagated sign |
5427 | bits, we can replace the logical shift with an arithmetic shift. */ | |
d0ab8cd3 RK |
5428 | else if (ashr_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing |
5429 | && (lshr_optab->handlers[(int) mode].insn_code | |
5430 | == CODE_FOR_nothing) | |
230d793d RS |
5431 | && GET_CODE (XEXP (x, 0)) == LSHIFTRT |
5432 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
5433 | && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 | |
5f4f0e22 CH |
5434 | && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT |
5435 | && mode_width <= HOST_BITS_PER_WIDE_INT) | |
230d793d | 5436 | { |
5f4f0e22 | 5437 | unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); |
230d793d RS |
5438 | |
5439 | mask >>= INTVAL (XEXP (XEXP (x, 0), 1)); | |
5440 | if ((INTVAL (XEXP (x, 1)) & ~mask) == 0) | |
5441 | SUBST (XEXP (x, 0), | |
280f58ba RK |
5442 | gen_rtx_combine (ASHIFTRT, mode, |
5443 | make_compound_operation (XEXP (XEXP (x, 0), 0), | |
5444 | next_code), | |
230d793d RS |
5445 | XEXP (XEXP (x, 0), 1))); |
5446 | } | |
5447 | ||
5448 | /* If the constant is one less than a power of two, this might be | |
5449 | representable by an extraction even if no shift is present. | |
5450 | If it doesn't end up being a ZERO_EXTEND, we will ignore it unless | |
5451 | we are in a COMPARE. */ | |
5452 | else if ((i = exact_log2 (INTVAL (XEXP (x, 1)) + 1)) >= 0) | |
280f58ba RK |
5453 | new = make_extraction (mode, |
5454 | make_compound_operation (XEXP (x, 0), | |
5455 | next_code), | |
5456 | 0, NULL_RTX, i, 1, 0, in_code == COMPARE); | |
230d793d RS |
5457 | |
5458 | /* If we are in a comparison and this is an AND with a power of two, | |
5459 | convert this into the appropriate bit extract. */ | |
5460 | else if (in_code == COMPARE | |
5461 | && (i = exact_log2 (INTVAL (XEXP (x, 1)))) >= 0) | |
280f58ba RK |
5462 | new = make_extraction (mode, |
5463 | make_compound_operation (XEXP (x, 0), | |
5464 | next_code), | |
5465 | i, NULL_RTX, 1, 1, 0, 1); | |
230d793d RS |
5466 | |
5467 | break; | |
5468 | ||
5469 | case LSHIFTRT: | |
5470 | /* If the sign bit is known to be zero, replace this with an | |
5471 | arithmetic shift. */ | |
d0ab8cd3 RK |
5472 | if (ashr_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing |
5473 | && lshr_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing | |
5f4f0e22 | 5474 | && mode_width <= HOST_BITS_PER_WIDE_INT |
951553af | 5475 | && (nonzero_bits (XEXP (x, 0), mode) & (1 << (mode_width - 1))) == 0) |
230d793d | 5476 | { |
280f58ba RK |
5477 | new = gen_rtx_combine (ASHIFTRT, mode, |
5478 | make_compound_operation (XEXP (x, 0), | |
5479 | next_code), | |
5480 | XEXP (x, 1)); | |
230d793d RS |
5481 | break; |
5482 | } | |
5483 | ||
5484 | /* ... fall through ... */ | |
5485 | ||
5486 | case ASHIFTRT: | |
71923da7 RK |
5487 | lhs = XEXP (x, 0); |
5488 | rhs = XEXP (x, 1); | |
5489 | ||
230d793d RS |
5490 | /* If we have (ashiftrt (ashift foo C1) C2) with C2 >= C1, |
5491 | this is a SIGN_EXTRACT. */ | |
71923da7 RK |
5492 | if (GET_CODE (rhs) == CONST_INT |
5493 | && GET_CODE (lhs) == ASHIFT | |
5494 | && GET_CODE (XEXP (lhs, 1)) == CONST_INT | |
5495 | && INTVAL (rhs) >= INTVAL (XEXP (lhs, 1))) | |
280f58ba | 5496 | { |
71923da7 | 5497 | new = make_compound_operation (XEXP (lhs, 0), next_code); |
280f58ba | 5498 | new = make_extraction (mode, new, |
71923da7 RK |
5499 | INTVAL (rhs) - INTVAL (XEXP (lhs, 1)), |
5500 | NULL_RTX, mode_width - INTVAL (rhs), | |
d0ab8cd3 RK |
5501 | code == LSHIFTRT, 0, in_code == COMPARE); |
5502 | } | |
5503 | ||
71923da7 RK |
5504 | /* See if we have operations between an ASHIFTRT and an ASHIFT. |
5505 | If so, try to merge the shifts into a SIGN_EXTEND. We could | |
5506 | also do this for some cases of SIGN_EXTRACT, but it doesn't | |
5507 | seem worth the effort; the case checked for occurs on Alpha. */ | |
5508 | ||
5509 | if (GET_RTX_CLASS (GET_CODE (lhs)) != 'o' | |
5510 | && ! (GET_CODE (lhs) == SUBREG | |
5511 | && (GET_RTX_CLASS (GET_CODE (SUBREG_REG (lhs))) == 'o')) | |
5512 | && GET_CODE (rhs) == CONST_INT | |
5513 | && INTVAL (rhs) < HOST_BITS_PER_WIDE_INT | |
5514 | && (new = extract_left_shift (lhs, INTVAL (rhs))) != 0) | |
5515 | new = make_extraction (mode, make_compound_operation (new, next_code), | |
5516 | 0, NULL_RTX, mode_width - INTVAL (rhs), | |
5517 | code == LSHIFTRT, 0, in_code == COMPARE); | |
5518 | ||
230d793d | 5519 | break; |
280f58ba RK |
5520 | |
5521 | case SUBREG: | |
5522 | /* Call ourselves recursively on the inner expression. If we are | |
5523 | narrowing the object and it has a different RTL code from | |
5524 | what it originally did, do this SUBREG as a force_to_mode. */ | |
5525 | ||
0a5cbff6 | 5526 | tem = make_compound_operation (SUBREG_REG (x), in_code); |
280f58ba RK |
5527 | if (GET_CODE (tem) != GET_CODE (SUBREG_REG (x)) |
5528 | && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (tem)) | |
5529 | && subreg_lowpart_p (x)) | |
0a5cbff6 RK |
5530 | { |
5531 | rtx newer = force_to_mode (tem, mode, | |
e3d616e3 | 5532 | GET_MODE_MASK (mode), NULL_RTX, 0); |
0a5cbff6 RK |
5533 | |
5534 | /* If we have something other than a SUBREG, we might have | |
5535 | done an expansion, so rerun outselves. */ | |
5536 | if (GET_CODE (newer) != SUBREG) | |
5537 | newer = make_compound_operation (newer, in_code); | |
5538 | ||
5539 | return newer; | |
5540 | } | |
230d793d RS |
5541 | } |
5542 | ||
5543 | if (new) | |
5544 | { | |
df62f951 | 5545 | x = gen_lowpart_for_combine (mode, new); |
230d793d RS |
5546 | code = GET_CODE (x); |
5547 | } | |
5548 | ||
5549 | /* Now recursively process each operand of this operation. */ | |
5550 | fmt = GET_RTX_FORMAT (code); | |
5551 | for (i = 0; i < GET_RTX_LENGTH (code); i++) | |
5552 | if (fmt[i] == 'e') | |
5553 | { | |
5554 | new = make_compound_operation (XEXP (x, i), next_code); | |
5555 | SUBST (XEXP (x, i), new); | |
5556 | } | |
5557 | ||
5558 | return x; | |
5559 | } | |
5560 | \f | |
5561 | /* Given M see if it is a value that would select a field of bits | |
5562 | within an item, but not the entire word. Return -1 if not. | |
5563 | Otherwise, return the starting position of the field, where 0 is the | |
5564 | low-order bit. | |
5565 | ||
5566 | *PLEN is set to the length of the field. */ | |
5567 | ||
5568 | static int | |
5569 | get_pos_from_mask (m, plen) | |
5f4f0e22 | 5570 | unsigned HOST_WIDE_INT m; |
230d793d RS |
5571 | int *plen; |
5572 | { | |
5573 | /* Get the bit number of the first 1 bit from the right, -1 if none. */ | |
5574 | int pos = exact_log2 (m & - m); | |
5575 | ||
5576 | if (pos < 0) | |
5577 | return -1; | |
5578 | ||
5579 | /* Now shift off the low-order zero bits and see if we have a power of | |
5580 | two minus 1. */ | |
5581 | *plen = exact_log2 ((m >> pos) + 1); | |
5582 | ||
5583 | if (*plen <= 0) | |
5584 | return -1; | |
5585 | ||
5586 | return pos; | |
5587 | } | |
5588 | \f | |
6139ff20 RK |
5589 | /* See if X can be simplified knowing that we will only refer to it in |
5590 | MODE and will only refer to those bits that are nonzero in MASK. | |
5591 | If other bits are being computed or if masking operations are done | |
5592 | that select a superset of the bits in MASK, they can sometimes be | |
5593 | ignored. | |
5594 | ||
5595 | Return a possibly simplified expression, but always convert X to | |
5596 | MODE. If X is a CONST_INT, AND the CONST_INT with MASK. | |
dfbe1b2f RK |
5597 | |
5598 | Also, if REG is non-zero and X is a register equal in value to REG, | |
e3d616e3 RK |
5599 | replace X with REG. |
5600 | ||
5601 | If JUST_SELECT is nonzero, don't optimize by noticing that bits in MASK | |
5602 | are all off in X. This is used when X will be complemented, by either | |
180b8e4b | 5603 | NOT, NEG, or XOR. */ |
dfbe1b2f RK |
5604 | |
5605 | static rtx | |
e3d616e3 | 5606 | force_to_mode (x, mode, mask, reg, just_select) |
dfbe1b2f RK |
5607 | rtx x; |
5608 | enum machine_mode mode; | |
6139ff20 | 5609 | unsigned HOST_WIDE_INT mask; |
dfbe1b2f | 5610 | rtx reg; |
e3d616e3 | 5611 | int just_select; |
dfbe1b2f RK |
5612 | { |
5613 | enum rtx_code code = GET_CODE (x); | |
180b8e4b | 5614 | int next_select = just_select || code == XOR || code == NOT || code == NEG; |
ef026f91 RS |
5615 | enum machine_mode op_mode; |
5616 | unsigned HOST_WIDE_INT fuller_mask, nonzero; | |
6139ff20 RK |
5617 | rtx op0, op1, temp; |
5618 | ||
246e00f2 RK |
5619 | /* If this is a CALL, don't do anything. Some of the code below |
5620 | will do the wrong thing since the mode of a CALL is VOIDmode. */ | |
5621 | if (code == CALL) | |
5622 | return x; | |
5623 | ||
6139ff20 RK |
5624 | /* We want to perform the operation is its present mode unless we know |
5625 | that the operation is valid in MODE, in which case we do the operation | |
5626 | in MODE. */ | |
1c75dfa4 RK |
5627 | op_mode = ((GET_MODE_CLASS (mode) == GET_MODE_CLASS (GET_MODE (x)) |
5628 | && code_to_optab[(int) code] != 0 | |
ef026f91 RS |
5629 | && (code_to_optab[(int) code]->handlers[(int) mode].insn_code |
5630 | != CODE_FOR_nothing)) | |
5631 | ? mode : GET_MODE (x)); | |
e3d616e3 | 5632 | |
aa988991 RS |
5633 | /* It is not valid to do a right-shift in a narrower mode |
5634 | than the one it came in with. */ | |
5635 | if ((code == LSHIFTRT || code == ASHIFTRT) | |
5636 | && GET_MODE_BITSIZE (mode) < GET_MODE_BITSIZE (GET_MODE (x))) | |
5637 | op_mode = GET_MODE (x); | |
ef026f91 RS |
5638 | |
5639 | /* Truncate MASK to fit OP_MODE. */ | |
5640 | if (op_mode) | |
5641 | mask &= GET_MODE_MASK (op_mode); | |
6139ff20 RK |
5642 | |
5643 | /* When we have an arithmetic operation, or a shift whose count we | |
5644 | do not know, we need to assume that all bit the up to the highest-order | |
5645 | bit in MASK will be needed. This is how we form such a mask. */ | |
ef026f91 RS |
5646 | if (op_mode) |
5647 | fuller_mask = (GET_MODE_BITSIZE (op_mode) >= HOST_BITS_PER_WIDE_INT | |
5648 | ? GET_MODE_MASK (op_mode) | |
5649 | : ((HOST_WIDE_INT) 1 << (floor_log2 (mask) + 1)) - 1); | |
5650 | else | |
5651 | fuller_mask = ~ (HOST_WIDE_INT) 0; | |
5652 | ||
5653 | /* Determine what bits of X are guaranteed to be (non)zero. */ | |
5654 | nonzero = nonzero_bits (x, mode); | |
6139ff20 RK |
5655 | |
5656 | /* If none of the bits in X are needed, return a zero. */ | |
e3d616e3 | 5657 | if (! just_select && (nonzero & mask) == 0) |
6139ff20 | 5658 | return const0_rtx; |
dfbe1b2f | 5659 | |
6139ff20 RK |
5660 | /* If X is a CONST_INT, return a new one. Do this here since the |
5661 | test below will fail. */ | |
5662 | if (GET_CODE (x) == CONST_INT) | |
ceb7983c RK |
5663 | { |
5664 | HOST_WIDE_INT cval = INTVAL (x) & mask; | |
5665 | int width = GET_MODE_BITSIZE (mode); | |
5666 | ||
5667 | /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative | |
5668 | number, sign extend it. */ | |
5669 | if (width > 0 && width < HOST_BITS_PER_WIDE_INT | |
5670 | && (cval & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) | |
5671 | cval |= (HOST_WIDE_INT) -1 << width; | |
5672 | ||
5673 | return GEN_INT (cval); | |
5674 | } | |
dfbe1b2f | 5675 | |
180b8e4b RK |
5676 | /* If X is narrower than MODE and we want all the bits in X's mode, just |
5677 | get X in the proper mode. */ | |
5678 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (mode) | |
5679 | && (GET_MODE_MASK (GET_MODE (x)) & ~ mask) == 0) | |
dfbe1b2f RK |
5680 | return gen_lowpart_for_combine (mode, x); |
5681 | ||
71923da7 RK |
5682 | /* If we aren't changing the mode, X is not a SUBREG, and all zero bits in |
5683 | MASK are already known to be zero in X, we need not do anything. */ | |
5684 | if (GET_MODE (x) == mode && code != SUBREG && (~ mask & nonzero) == 0) | |
6139ff20 RK |
5685 | return x; |
5686 | ||
dfbe1b2f RK |
5687 | switch (code) |
5688 | { | |
6139ff20 RK |
5689 | case CLOBBER: |
5690 | /* If X is a (clobber (const_int)), return it since we know we are | |
5691 | generating something that won't match. */ | |
5692 | return x; | |
5693 | ||
5694 | #if ! BITS_BIG_ENDIAN | |
5695 | case USE: | |
5696 | /* X is a (use (mem ..)) that was made from a bit-field extraction that | |
5697 | spanned the boundary of the MEM. If we are now masking so it is | |
5698 | within that boundary, we don't need the USE any more. */ | |
5699 | if ((mask & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))) == 0) | |
e3d616e3 | 5700 | return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); |
6139ff20 RK |
5701 | #endif |
5702 | ||
dfbe1b2f RK |
5703 | case SIGN_EXTEND: |
5704 | case ZERO_EXTEND: | |
5705 | case ZERO_EXTRACT: | |
5706 | case SIGN_EXTRACT: | |
5707 | x = expand_compound_operation (x); | |
5708 | if (GET_CODE (x) != code) | |
e3d616e3 | 5709 | return force_to_mode (x, mode, mask, reg, next_select); |
dfbe1b2f RK |
5710 | break; |
5711 | ||
5712 | case REG: | |
5713 | if (reg != 0 && (rtx_equal_p (get_last_value (reg), x) | |
5714 | || rtx_equal_p (reg, get_last_value (x)))) | |
5715 | x = reg; | |
5716 | break; | |
5717 | ||
dfbe1b2f | 5718 | case SUBREG: |
6139ff20 | 5719 | if (subreg_lowpart_p (x) |
180b8e4b RK |
5720 | /* We can ignore the effect of this SUBREG if it narrows the mode or |
5721 | if the constant masks to zero all the bits the mode doesn't | |
5722 | have. */ | |
6139ff20 RK |
5723 | && ((GET_MODE_SIZE (GET_MODE (x)) |
5724 | < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) | |
6139ff20 RK |
5725 | || (0 == (mask |
5726 | & GET_MODE_MASK (GET_MODE (x)) | |
180b8e4b | 5727 | & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x))))))) |
e3d616e3 | 5728 | return force_to_mode (SUBREG_REG (x), mode, mask, reg, next_select); |
dfbe1b2f RK |
5729 | break; |
5730 | ||
5731 | case AND: | |
6139ff20 RK |
5732 | /* If this is an AND with a constant, convert it into an AND |
5733 | whose constant is the AND of that constant with MASK. If it | |
5734 | remains an AND of MASK, delete it since it is redundant. */ | |
dfbe1b2f | 5735 | |
6139ff20 RK |
5736 | if (GET_CODE (XEXP (x, 1)) == CONST_INT |
5737 | && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT) | |
dfbe1b2f | 5738 | { |
6139ff20 RK |
5739 | x = simplify_and_const_int (x, op_mode, XEXP (x, 0), |
5740 | mask & INTVAL (XEXP (x, 1))); | |
dfbe1b2f RK |
5741 | |
5742 | /* If X is still an AND, see if it is an AND with a mask that | |
71923da7 RK |
5743 | is just some low-order bits. If so, and it is MASK, we don't |
5744 | need it. */ | |
dfbe1b2f RK |
5745 | |
5746 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT | |
6139ff20 | 5747 | && INTVAL (XEXP (x, 1)) == mask) |
dfbe1b2f | 5748 | x = XEXP (x, 0); |
d0ab8cd3 | 5749 | |
71923da7 RK |
5750 | /* If it remains an AND, try making another AND with the bits |
5751 | in the mode mask that aren't in MASK turned on. If the | |
5752 | constant in the AND is wide enough, this might make a | |
5753 | cheaper constant. */ | |
5754 | ||
5755 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT | |
5756 | && GET_MODE_MASK (GET_MODE (x)) != mask) | |
5757 | { | |
5758 | HOST_WIDE_INT cval = (INTVAL (XEXP (x, 1)) | |
5759 | | (GET_MODE_MASK (GET_MODE (x)) & ~ mask)); | |
5760 | int width = GET_MODE_BITSIZE (GET_MODE (x)); | |
5761 | rtx y; | |
5762 | ||
5763 | /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative | |
5764 | number, sign extend it. */ | |
5765 | if (width > 0 && width < HOST_BITS_PER_WIDE_INT | |
5766 | && (cval & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) | |
5767 | cval |= (HOST_WIDE_INT) -1 << width; | |
5768 | ||
5769 | y = gen_binary (AND, GET_MODE (x), XEXP (x, 0), GEN_INT (cval)); | |
5770 | if (rtx_cost (y, SET) < rtx_cost (x, SET)) | |
5771 | x = y; | |
5772 | } | |
5773 | ||
d0ab8cd3 | 5774 | break; |
dfbe1b2f RK |
5775 | } |
5776 | ||
6139ff20 | 5777 | goto binop; |
dfbe1b2f RK |
5778 | |
5779 | case PLUS: | |
6139ff20 RK |
5780 | /* In (and (plus FOO C1) M), if M is a mask that just turns off |
5781 | low-order bits (as in an alignment operation) and FOO is already | |
5782 | aligned to that boundary, mask C1 to that boundary as well. | |
5783 | This may eliminate that PLUS and, later, the AND. */ | |
5784 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
5785 | && exact_log2 (- mask) >= 0 | |
5786 | && (nonzero_bits (XEXP (x, 0), mode) & ~ mask) == 0 | |
5787 | && (INTVAL (XEXP (x, 1)) & ~ mask) != 0) | |
5788 | return force_to_mode (plus_constant (XEXP (x, 0), | |
5789 | INTVAL (XEXP (x, 1)) & mask), | |
e3d616e3 | 5790 | mode, mask, reg, next_select); |
6139ff20 RK |
5791 | |
5792 | /* ... fall through ... */ | |
5793 | ||
dfbe1b2f RK |
5794 | case MINUS: |
5795 | case MULT: | |
6139ff20 RK |
5796 | /* For PLUS, MINUS and MULT, we need any bits less significant than the |
5797 | most significant bit in MASK since carries from those bits will | |
5798 | affect the bits we are interested in. */ | |
5799 | mask = fuller_mask; | |
5800 | goto binop; | |
5801 | ||
dfbe1b2f RK |
5802 | case IOR: |
5803 | case XOR: | |
6139ff20 RK |
5804 | /* If X is (ior (lshiftrt FOO C1) C2), try to commute the IOR and |
5805 | LSHIFTRT so we end up with an (and (lshiftrt (ior ...) ...) ...) | |
5806 | operation which may be a bitfield extraction. Ensure that the | |
5807 | constant we form is not wider than the mode of X. */ | |
5808 | ||
5809 | if (GET_CODE (XEXP (x, 0)) == LSHIFTRT | |
5810 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
5811 | && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 | |
5812 | && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT | |
5813 | && GET_CODE (XEXP (x, 1)) == CONST_INT | |
5814 | && ((INTVAL (XEXP (XEXP (x, 0), 1)) | |
5815 | + floor_log2 (INTVAL (XEXP (x, 1)))) | |
5816 | < GET_MODE_BITSIZE (GET_MODE (x))) | |
5817 | && (INTVAL (XEXP (x, 1)) | |
5818 | & ~ nonzero_bits (XEXP (x, 0), GET_MODE (x)) == 0)) | |
5819 | { | |
5820 | temp = GEN_INT ((INTVAL (XEXP (x, 1)) & mask) | |
5821 | << INTVAL (XEXP (XEXP (x, 0), 1))); | |
5822 | temp = gen_binary (GET_CODE (x), GET_MODE (x), | |
5823 | XEXP (XEXP (x, 0), 0), temp); | |
5824 | x = gen_binary (LSHIFTRT, GET_MODE (x), temp, XEXP (x, 1)); | |
e3d616e3 | 5825 | return force_to_mode (x, mode, mask, reg, next_select); |
6139ff20 RK |
5826 | } |
5827 | ||
5828 | binop: | |
dfbe1b2f | 5829 | /* For most binary operations, just propagate into the operation and |
6139ff20 RK |
5830 | change the mode if we have an operation of that mode. */ |
5831 | ||
e3d616e3 RK |
5832 | op0 = gen_lowpart_for_combine (op_mode, |
5833 | force_to_mode (XEXP (x, 0), mode, mask, | |
5834 | reg, next_select)); | |
5835 | op1 = gen_lowpart_for_combine (op_mode, | |
5836 | force_to_mode (XEXP (x, 1), mode, mask, | |
5837 | reg, next_select)); | |
6139ff20 | 5838 | |
2dd484ed RK |
5839 | /* If OP1 is a CONST_INT and X is an IOR or XOR, clear bits outside |
5840 | MASK since OP1 might have been sign-extended but we never want | |
5841 | to turn on extra bits, since combine might have previously relied | |
5842 | on them being off. */ | |
5843 | if (GET_CODE (op1) == CONST_INT && (code == IOR || code == XOR) | |
5844 | && (INTVAL (op1) & mask) != 0) | |
5845 | op1 = GEN_INT (INTVAL (op1) & mask); | |
5846 | ||
6139ff20 RK |
5847 | if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0) || op1 != XEXP (x, 1)) |
5848 | x = gen_binary (code, op_mode, op0, op1); | |
d0ab8cd3 | 5849 | break; |
dfbe1b2f RK |
5850 | |
5851 | case ASHIFT: | |
dfbe1b2f | 5852 | /* For left shifts, do the same, but just for the first operand. |
f6785026 RK |
5853 | However, we cannot do anything with shifts where we cannot |
5854 | guarantee that the counts are smaller than the size of the mode | |
5855 | because such a count will have a different meaning in a | |
6139ff20 | 5856 | wider mode. */ |
f6785026 RK |
5857 | |
5858 | if (! (GET_CODE (XEXP (x, 1)) == CONST_INT | |
6139ff20 | 5859 | && INTVAL (XEXP (x, 1)) >= 0 |
f6785026 RK |
5860 | && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (mode)) |
5861 | && ! (GET_MODE (XEXP (x, 1)) != VOIDmode | |
5862 | && (nonzero_bits (XEXP (x, 1), GET_MODE (XEXP (x, 1))) | |
adb7a1cb | 5863 | < (unsigned HOST_WIDE_INT) GET_MODE_BITSIZE (mode)))) |
f6785026 RK |
5864 | break; |
5865 | ||
6139ff20 RK |
5866 | /* If the shift count is a constant and we can do arithmetic in |
5867 | the mode of the shift, refine which bits we need. Otherwise, use the | |
5868 | conservative form of the mask. */ | |
5869 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
5870 | && INTVAL (XEXP (x, 1)) >= 0 | |
5871 | && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (op_mode) | |
5872 | && GET_MODE_BITSIZE (op_mode) <= HOST_BITS_PER_WIDE_INT) | |
5873 | mask >>= INTVAL (XEXP (x, 1)); | |
5874 | else | |
5875 | mask = fuller_mask; | |
5876 | ||
5877 | op0 = gen_lowpart_for_combine (op_mode, | |
5878 | force_to_mode (XEXP (x, 0), op_mode, | |
e3d616e3 | 5879 | mask, reg, next_select)); |
6139ff20 RK |
5880 | |
5881 | if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0)) | |
5882 | x = gen_binary (code, op_mode, op0, XEXP (x, 1)); | |
d0ab8cd3 | 5883 | break; |
dfbe1b2f RK |
5884 | |
5885 | case LSHIFTRT: | |
1347292b JW |
5886 | /* Here we can only do something if the shift count is a constant, |
5887 | this shift constant is valid for the host, and we can do arithmetic | |
5888 | in OP_MODE. */ | |
dfbe1b2f RK |
5889 | |
5890 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
1347292b | 5891 | && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT |
6139ff20 | 5892 | && GET_MODE_BITSIZE (op_mode) <= HOST_BITS_PER_WIDE_INT) |
d0ab8cd3 | 5893 | { |
6139ff20 RK |
5894 | rtx inner = XEXP (x, 0); |
5895 | ||
5896 | /* Select the mask of the bits we need for the shift operand. */ | |
5897 | mask <<= INTVAL (XEXP (x, 1)); | |
d0ab8cd3 | 5898 | |
6139ff20 RK |
5899 | /* We can only change the mode of the shift if we can do arithmetic |
5900 | in the mode of the shift and MASK is no wider than the width of | |
5901 | OP_MODE. */ | |
5902 | if (GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT | |
5903 | || (mask & ~ GET_MODE_MASK (op_mode)) != 0) | |
d0ab8cd3 RK |
5904 | op_mode = GET_MODE (x); |
5905 | ||
e3d616e3 | 5906 | inner = force_to_mode (inner, op_mode, mask, reg, next_select); |
6139ff20 RK |
5907 | |
5908 | if (GET_MODE (x) != op_mode || inner != XEXP (x, 0)) | |
5909 | x = gen_binary (LSHIFTRT, op_mode, inner, XEXP (x, 1)); | |
d0ab8cd3 | 5910 | } |
6139ff20 RK |
5911 | |
5912 | /* If we have (and (lshiftrt FOO C1) C2) where the combination of the | |
5913 | shift and AND produces only copies of the sign bit (C2 is one less | |
5914 | than a power of two), we can do this with just a shift. */ | |
5915 | ||
5916 | if (GET_CODE (x) == LSHIFTRT | |
5917 | && GET_CODE (XEXP (x, 1)) == CONST_INT | |
5918 | && ((INTVAL (XEXP (x, 1)) | |
5919 | + num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0)))) | |
5920 | >= GET_MODE_BITSIZE (GET_MODE (x))) | |
5921 | && exact_log2 (mask + 1) >= 0 | |
5922 | && (num_sign_bit_copies (XEXP (x, 0), GET_MODE (XEXP (x, 0))) | |
5923 | >= exact_log2 (mask + 1))) | |
5924 | x = gen_binary (LSHIFTRT, GET_MODE (x), XEXP (x, 0), | |
5925 | GEN_INT (GET_MODE_BITSIZE (GET_MODE (x)) | |
5926 | - exact_log2 (mask + 1))); | |
d0ab8cd3 RK |
5927 | break; |
5928 | ||
5929 | case ASHIFTRT: | |
6139ff20 RK |
5930 | /* If we are just looking for the sign bit, we don't need this shift at |
5931 | all, even if it has a variable count. */ | |
5932 | if (mask == ((HOST_WIDE_INT) 1 | |
5933 | << (GET_MODE_BITSIZE (GET_MODE (x)) - 1))) | |
e3d616e3 | 5934 | return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); |
6139ff20 RK |
5935 | |
5936 | /* If this is a shift by a constant, get a mask that contains those bits | |
5937 | that are not copies of the sign bit. We then have two cases: If | |
5938 | MASK only includes those bits, this can be a logical shift, which may | |
5939 | allow simplifications. If MASK is a single-bit field not within | |
5940 | those bits, we are requesting a copy of the sign bit and hence can | |
5941 | shift the sign bit to the appropriate location. */ | |
5942 | ||
5943 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) >= 0 | |
5944 | && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) | |
5945 | { | |
5946 | int i = -1; | |
5947 | ||
5948 | nonzero = GET_MODE_MASK (GET_MODE (x)); | |
5949 | nonzero >>= INTVAL (XEXP (x, 1)); | |
5950 | ||
5951 | if ((mask & ~ nonzero) == 0 | |
5952 | || (i = exact_log2 (mask)) >= 0) | |
5953 | { | |
5954 | x = simplify_shift_const | |
5955 | (x, LSHIFTRT, GET_MODE (x), XEXP (x, 0), | |
5956 | i < 0 ? INTVAL (XEXP (x, 1)) | |
5957 | : GET_MODE_BITSIZE (GET_MODE (x)) - 1 - i); | |
5958 | ||
5959 | if (GET_CODE (x) != ASHIFTRT) | |
e3d616e3 | 5960 | return force_to_mode (x, mode, mask, reg, next_select); |
6139ff20 RK |
5961 | } |
5962 | } | |
5963 | ||
5964 | /* If MASK is 1, convert this to a LSHIFTRT. This can be done | |
5965 | even if the shift count isn't a constant. */ | |
5966 | if (mask == 1) | |
5967 | x = gen_binary (LSHIFTRT, GET_MODE (x), XEXP (x, 0), XEXP (x, 1)); | |
5968 | ||
d0ab8cd3 | 5969 | /* If this is a sign-extension operation that just affects bits |
4c002f29 RK |
5970 | we don't care about, remove it. Be sure the call above returned |
5971 | something that is still a shift. */ | |
d0ab8cd3 | 5972 | |
4c002f29 RK |
5973 | if ((GET_CODE (x) == LSHIFTRT || GET_CODE (x) == ASHIFTRT) |
5974 | && GET_CODE (XEXP (x, 1)) == CONST_INT | |
d0ab8cd3 | 5975 | && INTVAL (XEXP (x, 1)) >= 0 |
6139ff20 RK |
5976 | && (INTVAL (XEXP (x, 1)) |
5977 | <= GET_MODE_BITSIZE (GET_MODE (x)) - (floor_log2 (mask) + 1)) | |
d0ab8cd3 RK |
5978 | && GET_CODE (XEXP (x, 0)) == ASHIFT |
5979 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
5980 | && INTVAL (XEXP (XEXP (x, 0), 1)) == INTVAL (XEXP (x, 1))) | |
e3d616e3 RK |
5981 | return force_to_mode (XEXP (XEXP (x, 0), 0), mode, mask, |
5982 | reg, next_select); | |
6139ff20 | 5983 | |
dfbe1b2f RK |
5984 | break; |
5985 | ||
6139ff20 RK |
5986 | case ROTATE: |
5987 | case ROTATERT: | |
5988 | /* If the shift count is constant and we can do computations | |
5989 | in the mode of X, compute where the bits we care about are. | |
5990 | Otherwise, we can't do anything. Don't change the mode of | |
5991 | the shift or propagate MODE into the shift, though. */ | |
5992 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
5993 | && INTVAL (XEXP (x, 1)) >= 0) | |
5994 | { | |
5995 | temp = simplify_binary_operation (code == ROTATE ? ROTATERT : ROTATE, | |
5996 | GET_MODE (x), GEN_INT (mask), | |
5997 | XEXP (x, 1)); | |
7d171a1e | 5998 | if (temp && GET_CODE(temp) == CONST_INT) |
6139ff20 RK |
5999 | SUBST (XEXP (x, 0), |
6000 | force_to_mode (XEXP (x, 0), GET_MODE (x), | |
e3d616e3 | 6001 | INTVAL (temp), reg, next_select)); |
6139ff20 RK |
6002 | } |
6003 | break; | |
6004 | ||
dfbe1b2f | 6005 | case NEG: |
180b8e4b RK |
6006 | /* If we just want the low-order bit, the NEG isn't needed since it |
6007 | won't change the low-order bit. */ | |
6008 | if (mask == 1) | |
6009 | return force_to_mode (XEXP (x, 0), mode, mask, reg, just_select); | |
6010 | ||
6139ff20 RK |
6011 | /* We need any bits less significant than the most significant bit in |
6012 | MASK since carries from those bits will affect the bits we are | |
6013 | interested in. */ | |
6014 | mask = fuller_mask; | |
6015 | goto unop; | |
6016 | ||
dfbe1b2f | 6017 | case NOT: |
6139ff20 RK |
6018 | /* (not FOO) is (xor FOO CONST), so if FOO is an LSHIFTRT, we can do the |
6019 | same as the XOR case above. Ensure that the constant we form is not | |
6020 | wider than the mode of X. */ | |
6021 | ||
6022 | if (GET_CODE (XEXP (x, 0)) == LSHIFTRT | |
6023 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
6024 | && INTVAL (XEXP (XEXP (x, 0), 1)) >= 0 | |
6025 | && (INTVAL (XEXP (XEXP (x, 0), 1)) + floor_log2 (mask) | |
6026 | < GET_MODE_BITSIZE (GET_MODE (x))) | |
6027 | && INTVAL (XEXP (XEXP (x, 0), 1)) < HOST_BITS_PER_WIDE_INT) | |
6028 | { | |
6029 | temp = GEN_INT (mask << INTVAL (XEXP (XEXP (x, 0), 1))); | |
6030 | temp = gen_binary (XOR, GET_MODE (x), XEXP (XEXP (x, 0), 0), temp); | |
6031 | x = gen_binary (LSHIFTRT, GET_MODE (x), temp, XEXP (XEXP (x, 0), 1)); | |
6032 | ||
e3d616e3 | 6033 | return force_to_mode (x, mode, mask, reg, next_select); |
6139ff20 RK |
6034 | } |
6035 | ||
6036 | unop: | |
e3d616e3 RK |
6037 | op0 = gen_lowpart_for_combine (op_mode, |
6038 | force_to_mode (XEXP (x, 0), mode, mask, | |
6039 | reg, next_select)); | |
6139ff20 | 6040 | if (op_mode != GET_MODE (x) || op0 != XEXP (x, 0)) |
0c1c8ea6 | 6041 | x = gen_unary (code, op_mode, op_mode, op0); |
6139ff20 RK |
6042 | break; |
6043 | ||
6044 | case NE: | |
6045 | /* (and (ne FOO 0) CONST) can be (and FOO CONST) if CONST is included | |
6046 | in STORE_FLAG_VALUE and FOO has no bits that might be nonzero not | |
6047 | in CONST. */ | |
6048 | if ((mask & ~ STORE_FLAG_VALUE) == 0 && XEXP (x, 0) == const0_rtx | |
6049 | && (nonzero_bits (XEXP (x, 0), mode) & ~ mask) == 0) | |
e3d616e3 | 6050 | return force_to_mode (XEXP (x, 0), mode, mask, reg, next_select); |
6139ff20 | 6051 | |
d0ab8cd3 RK |
6052 | break; |
6053 | ||
6054 | case IF_THEN_ELSE: | |
6055 | /* We have no way of knowing if the IF_THEN_ELSE can itself be | |
6056 | written in a narrower mode. We play it safe and do not do so. */ | |
6057 | ||
6058 | SUBST (XEXP (x, 1), | |
6059 | gen_lowpart_for_combine (GET_MODE (x), | |
6060 | force_to_mode (XEXP (x, 1), mode, | |
e3d616e3 | 6061 | mask, reg, next_select))); |
d0ab8cd3 RK |
6062 | SUBST (XEXP (x, 2), |
6063 | gen_lowpart_for_combine (GET_MODE (x), | |
6064 | force_to_mode (XEXP (x, 2), mode, | |
e3d616e3 | 6065 | mask, reg,next_select))); |
d0ab8cd3 | 6066 | break; |
dfbe1b2f RK |
6067 | } |
6068 | ||
d0ab8cd3 | 6069 | /* Ensure we return a value of the proper mode. */ |
dfbe1b2f RK |
6070 | return gen_lowpart_for_combine (mode, x); |
6071 | } | |
6072 | \f | |
abe6e52f RK |
6073 | /* Return nonzero if X is an expression that has one of two values depending on |
6074 | whether some other value is zero or nonzero. In that case, we return the | |
6075 | value that is being tested, *PTRUE is set to the value if the rtx being | |
6076 | returned has a nonzero value, and *PFALSE is set to the other alternative. | |
6077 | ||
6078 | If we return zero, we set *PTRUE and *PFALSE to X. */ | |
6079 | ||
6080 | static rtx | |
6081 | if_then_else_cond (x, ptrue, pfalse) | |
6082 | rtx x; | |
6083 | rtx *ptrue, *pfalse; | |
6084 | { | |
6085 | enum machine_mode mode = GET_MODE (x); | |
6086 | enum rtx_code code = GET_CODE (x); | |
6087 | int size = GET_MODE_BITSIZE (mode); | |
6088 | rtx cond0, cond1, true0, true1, false0, false1; | |
6089 | unsigned HOST_WIDE_INT nz; | |
6090 | ||
6091 | /* If this is a unary operation whose operand has one of two values, apply | |
6092 | our opcode to compute those values. */ | |
6093 | if (GET_RTX_CLASS (code) == '1' | |
6094 | && (cond0 = if_then_else_cond (XEXP (x, 0), &true0, &false0)) != 0) | |
6095 | { | |
0c1c8ea6 RK |
6096 | *ptrue = gen_unary (code, mode, GET_MODE (XEXP (x, 0)), true0); |
6097 | *pfalse = gen_unary (code, mode, GET_MODE (XEXP (x, 0)), false0); | |
abe6e52f RK |
6098 | return cond0; |
6099 | } | |
6100 | ||
3a19aabc RK |
6101 | /* If this is a COMPARE, do nothing, since the IF_THEN_ELSE we would |
6102 | make can't possibly match and would supress other optimizations. */ | |
6103 | else if (code == COMPARE) | |
6104 | ; | |
6105 | ||
abe6e52f RK |
6106 | /* If this is a binary operation, see if either side has only one of two |
6107 | values. If either one does or if both do and they are conditional on | |
6108 | the same value, compute the new true and false values. */ | |
6109 | else if (GET_RTX_CLASS (code) == 'c' || GET_RTX_CLASS (code) == '2' | |
6110 | || GET_RTX_CLASS (code) == '<') | |
6111 | { | |
6112 | cond0 = if_then_else_cond (XEXP (x, 0), &true0, &false0); | |
6113 | cond1 = if_then_else_cond (XEXP (x, 1), &true1, &false1); | |
6114 | ||
6115 | if ((cond0 != 0 || cond1 != 0) | |
6116 | && ! (cond0 != 0 && cond1 != 0 && ! rtx_equal_p (cond0, cond1))) | |
6117 | { | |
6118 | *ptrue = gen_binary (code, mode, true0, true1); | |
6119 | *pfalse = gen_binary (code, mode, false0, false1); | |
6120 | return cond0 ? cond0 : cond1; | |
6121 | } | |
9210df58 RK |
6122 | |
6123 | #if STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1 | |
6124 | ||
6125 | /* See if we have PLUS, IOR, XOR, MINUS or UMAX, where one of the | |
6126 | operands is zero when the other is non-zero, and vice-versa. */ | |
6127 | ||
6128 | if ((code == PLUS || code == IOR || code == XOR || code == MINUS | |
6129 | || code == UMAX) | |
6130 | && GET_CODE (XEXP (x, 0)) == MULT && GET_CODE (XEXP (x, 1)) == MULT) | |
6131 | { | |
6132 | rtx op0 = XEXP (XEXP (x, 0), 1); | |
6133 | rtx op1 = XEXP (XEXP (x, 1), 1); | |
6134 | ||
6135 | cond0 = XEXP (XEXP (x, 0), 0); | |
6136 | cond1 = XEXP (XEXP (x, 1), 0); | |
6137 | ||
6138 | if (GET_RTX_CLASS (GET_CODE (cond0)) == '<' | |
6139 | && GET_RTX_CLASS (GET_CODE (cond1)) == '<' | |
6140 | && reversible_comparison_p (cond1) | |
6141 | && ((GET_CODE (cond0) == reverse_condition (GET_CODE (cond1)) | |
6142 | && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 0)) | |
6143 | && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 1))) | |
6144 | || ((swap_condition (GET_CODE (cond0)) | |
6145 | == reverse_condition (GET_CODE (cond1))) | |
6146 | && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 1)) | |
6147 | && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 0)))) | |
6148 | && ! side_effects_p (x)) | |
6149 | { | |
6150 | *ptrue = gen_binary (MULT, mode, op0, const_true_rtx); | |
6151 | *pfalse = gen_binary (MULT, mode, | |
6152 | (code == MINUS | |
0c1c8ea6 | 6153 | ? gen_unary (NEG, mode, mode, op1) : op1), |
9210df58 RK |
6154 | const_true_rtx); |
6155 | return cond0; | |
6156 | } | |
6157 | } | |
6158 | ||
6159 | /* Similarly for MULT, AND and UMIN, execpt that for these the result | |
6160 | is always zero. */ | |
6161 | if ((code == MULT || code == AND || code == UMIN) | |
6162 | && GET_CODE (XEXP (x, 0)) == MULT && GET_CODE (XEXP (x, 1)) == MULT) | |
6163 | { | |
6164 | cond0 = XEXP (XEXP (x, 0), 0); | |
6165 | cond1 = XEXP (XEXP (x, 1), 0); | |
6166 | ||
6167 | if (GET_RTX_CLASS (GET_CODE (cond0)) == '<' | |
6168 | && GET_RTX_CLASS (GET_CODE (cond1)) == '<' | |
6169 | && reversible_comparison_p (cond1) | |
6170 | && ((GET_CODE (cond0) == reverse_condition (GET_CODE (cond1)) | |
6171 | && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 0)) | |
6172 | && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 1))) | |
6173 | || ((swap_condition (GET_CODE (cond0)) | |
6174 | == reverse_condition (GET_CODE (cond1))) | |
6175 | && rtx_equal_p (XEXP (cond0, 0), XEXP (cond1, 1)) | |
6176 | && rtx_equal_p (XEXP (cond0, 1), XEXP (cond1, 0)))) | |
6177 | && ! side_effects_p (x)) | |
6178 | { | |
6179 | *ptrue = *pfalse = const0_rtx; | |
6180 | return cond0; | |
6181 | } | |
6182 | } | |
6183 | #endif | |
abe6e52f RK |
6184 | } |
6185 | ||
6186 | else if (code == IF_THEN_ELSE) | |
6187 | { | |
6188 | /* If we have IF_THEN_ELSE already, extract the condition and | |
6189 | canonicalize it if it is NE or EQ. */ | |
6190 | cond0 = XEXP (x, 0); | |
6191 | *ptrue = XEXP (x, 1), *pfalse = XEXP (x, 2); | |
6192 | if (GET_CODE (cond0) == NE && XEXP (cond0, 1) == const0_rtx) | |
6193 | return XEXP (cond0, 0); | |
6194 | else if (GET_CODE (cond0) == EQ && XEXP (cond0, 1) == const0_rtx) | |
6195 | { | |
6196 | *ptrue = XEXP (x, 2), *pfalse = XEXP (x, 1); | |
6197 | return XEXP (cond0, 0); | |
6198 | } | |
6199 | else | |
6200 | return cond0; | |
6201 | } | |
6202 | ||
6203 | /* If X is a normal SUBREG with both inner and outer modes integral, | |
6204 | we can narrow both the true and false values of the inner expression, | |
6205 | if there is a condition. */ | |
6206 | else if (code == SUBREG && GET_MODE_CLASS (mode) == MODE_INT | |
6207 | && GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT | |
6208 | && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) | |
6209 | && 0 != (cond0 = if_then_else_cond (SUBREG_REG (x), | |
6210 | &true0, &false0))) | |
6211 | { | |
00244e6b RK |
6212 | *ptrue = force_to_mode (true0, mode, GET_MODE_MASK (mode), NULL_RTX, 0); |
6213 | *pfalse | |
6214 | = force_to_mode (false0, mode, GET_MODE_MASK (mode), NULL_RTX, 0); | |
abe6e52f | 6215 | |
abe6e52f RK |
6216 | return cond0; |
6217 | } | |
6218 | ||
6219 | /* If X is a constant, this isn't special and will cause confusions | |
6220 | if we treat it as such. Likewise if it is equivalent to a constant. */ | |
6221 | else if (CONSTANT_P (x) | |
6222 | || ((cond0 = get_last_value (x)) != 0 && CONSTANT_P (cond0))) | |
6223 | ; | |
6224 | ||
6225 | /* If X is known to be either 0 or -1, those are the true and | |
6226 | false values when testing X. */ | |
6227 | else if (num_sign_bit_copies (x, mode) == size) | |
6228 | { | |
6229 | *ptrue = constm1_rtx, *pfalse = const0_rtx; | |
6230 | return x; | |
6231 | } | |
6232 | ||
6233 | /* Likewise for 0 or a single bit. */ | |
6234 | else if (exact_log2 (nz = nonzero_bits (x, mode)) >= 0) | |
6235 | { | |
6236 | *ptrue = GEN_INT (nz), *pfalse = const0_rtx; | |
6237 | return x; | |
6238 | } | |
6239 | ||
6240 | /* Otherwise fail; show no condition with true and false values the same. */ | |
6241 | *ptrue = *pfalse = x; | |
6242 | return 0; | |
6243 | } | |
6244 | \f | |
1a26b032 RK |
6245 | /* Return the value of expression X given the fact that condition COND |
6246 | is known to be true when applied to REG as its first operand and VAL | |
6247 | as its second. X is known to not be shared and so can be modified in | |
6248 | place. | |
6249 | ||
6250 | We only handle the simplest cases, and specifically those cases that | |
6251 | arise with IF_THEN_ELSE expressions. */ | |
6252 | ||
6253 | static rtx | |
6254 | known_cond (x, cond, reg, val) | |
6255 | rtx x; | |
6256 | enum rtx_code cond; | |
6257 | rtx reg, val; | |
6258 | { | |
6259 | enum rtx_code code = GET_CODE (x); | |
f24ad0e4 | 6260 | rtx temp; |
1a26b032 RK |
6261 | char *fmt; |
6262 | int i, j; | |
6263 | ||
6264 | if (side_effects_p (x)) | |
6265 | return x; | |
6266 | ||
6267 | if (cond == EQ && rtx_equal_p (x, reg)) | |
6268 | return val; | |
6269 | ||
6270 | /* If X is (abs REG) and we know something about REG's relationship | |
6271 | with zero, we may be able to simplify this. */ | |
6272 | ||
6273 | if (code == ABS && rtx_equal_p (XEXP (x, 0), reg) && val == const0_rtx) | |
6274 | switch (cond) | |
6275 | { | |
6276 | case GE: case GT: case EQ: | |
6277 | return XEXP (x, 0); | |
6278 | case LT: case LE: | |
0c1c8ea6 RK |
6279 | return gen_unary (NEG, GET_MODE (XEXP (x, 0)), GET_MODE (XEXP (x, 0)), |
6280 | XEXP (x, 0)); | |
1a26b032 RK |
6281 | } |
6282 | ||
6283 | /* The only other cases we handle are MIN, MAX, and comparisons if the | |
6284 | operands are the same as REG and VAL. */ | |
6285 | ||
6286 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == 'c') | |
6287 | { | |
6288 | if (rtx_equal_p (XEXP (x, 0), val)) | |
6289 | cond = swap_condition (cond), temp = val, val = reg, reg = temp; | |
6290 | ||
6291 | if (rtx_equal_p (XEXP (x, 0), reg) && rtx_equal_p (XEXP (x, 1), val)) | |
6292 | { | |
6293 | if (GET_RTX_CLASS (code) == '<') | |
6294 | return (comparison_dominates_p (cond, code) ? const_true_rtx | |
6295 | : (comparison_dominates_p (cond, | |
6296 | reverse_condition (code)) | |
6297 | ? const0_rtx : x)); | |
6298 | ||
6299 | else if (code == SMAX || code == SMIN | |
6300 | || code == UMIN || code == UMAX) | |
6301 | { | |
6302 | int unsignedp = (code == UMIN || code == UMAX); | |
6303 | ||
6304 | if (code == SMAX || code == UMAX) | |
6305 | cond = reverse_condition (cond); | |
6306 | ||
6307 | switch (cond) | |
6308 | { | |
6309 | case GE: case GT: | |
6310 | return unsignedp ? x : XEXP (x, 1); | |
6311 | case LE: case LT: | |
6312 | return unsignedp ? x : XEXP (x, 0); | |
6313 | case GEU: case GTU: | |
6314 | return unsignedp ? XEXP (x, 1) : x; | |
6315 | case LEU: case LTU: | |
6316 | return unsignedp ? XEXP (x, 0) : x; | |
6317 | } | |
6318 | } | |
6319 | } | |
6320 | } | |
6321 | ||
6322 | fmt = GET_RTX_FORMAT (code); | |
6323 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
6324 | { | |
6325 | if (fmt[i] == 'e') | |
6326 | SUBST (XEXP (x, i), known_cond (XEXP (x, i), cond, reg, val)); | |
6327 | else if (fmt[i] == 'E') | |
6328 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
6329 | SUBST (XVECEXP (x, i, j), known_cond (XVECEXP (x, i, j), | |
6330 | cond, reg, val)); | |
6331 | } | |
6332 | ||
6333 | return x; | |
6334 | } | |
6335 | \f | |
230d793d RS |
6336 | /* See if X, a SET operation, can be rewritten as a bit-field assignment. |
6337 | Return that assignment if so. | |
6338 | ||
6339 | We only handle the most common cases. */ | |
6340 | ||
6341 | static rtx | |
6342 | make_field_assignment (x) | |
6343 | rtx x; | |
6344 | { | |
6345 | rtx dest = SET_DEST (x); | |
6346 | rtx src = SET_SRC (x); | |
dfbe1b2f | 6347 | rtx assign; |
5f4f0e22 CH |
6348 | HOST_WIDE_INT c1; |
6349 | int pos, len; | |
dfbe1b2f RK |
6350 | rtx other; |
6351 | enum machine_mode mode; | |
230d793d RS |
6352 | |
6353 | /* If SRC was (and (not (ashift (const_int 1) POS)) DEST), this is | |
6354 | a clear of a one-bit field. We will have changed it to | |
6355 | (and (rotate (const_int -2) POS) DEST), so check for that. Also check | |
6356 | for a SUBREG. */ | |
6357 | ||
6358 | if (GET_CODE (src) == AND && GET_CODE (XEXP (src, 0)) == ROTATE | |
6359 | && GET_CODE (XEXP (XEXP (src, 0), 0)) == CONST_INT | |
6360 | && INTVAL (XEXP (XEXP (src, 0), 0)) == -2 | |
dfbe1b2f RK |
6361 | && (rtx_equal_p (dest, XEXP (src, 1)) |
6362 | || rtx_equal_p (dest, get_last_value (XEXP (src, 1))) | |
6363 | || rtx_equal_p (get_last_value (dest), XEXP (src, 1)))) | |
230d793d | 6364 | { |
8999a12e | 6365 | assign = make_extraction (VOIDmode, dest, 0, XEXP (XEXP (src, 0), 1), |
230d793d | 6366 | 1, 1, 1, 0); |
dfbe1b2f | 6367 | return gen_rtx (SET, VOIDmode, assign, const0_rtx); |
230d793d RS |
6368 | } |
6369 | ||
6370 | else if (GET_CODE (src) == AND && GET_CODE (XEXP (src, 0)) == SUBREG | |
6371 | && subreg_lowpart_p (XEXP (src, 0)) | |
6372 | && (GET_MODE_SIZE (GET_MODE (XEXP (src, 0))) | |
6373 | < GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (src, 0))))) | |
6374 | && GET_CODE (SUBREG_REG (XEXP (src, 0))) == ROTATE | |
6375 | && INTVAL (XEXP (SUBREG_REG (XEXP (src, 0)), 0)) == -2 | |
dfbe1b2f RK |
6376 | && (rtx_equal_p (dest, XEXP (src, 1)) |
6377 | || rtx_equal_p (dest, get_last_value (XEXP (src, 1))) | |
6378 | || rtx_equal_p (get_last_value (dest), XEXP (src, 1)))) | |
230d793d | 6379 | { |
8999a12e | 6380 | assign = make_extraction (VOIDmode, dest, 0, |
230d793d RS |
6381 | XEXP (SUBREG_REG (XEXP (src, 0)), 1), |
6382 | 1, 1, 1, 0); | |
dfbe1b2f | 6383 | return gen_rtx (SET, VOIDmode, assign, const0_rtx); |
230d793d RS |
6384 | } |
6385 | ||
6386 | /* If SRC is (ior (ashift (const_int 1) POS DEST)), this is a set of a | |
6387 | one-bit field. */ | |
6388 | else if (GET_CODE (src) == IOR && GET_CODE (XEXP (src, 0)) == ASHIFT | |
6389 | && XEXP (XEXP (src, 0), 0) == const1_rtx | |
dfbe1b2f RK |
6390 | && (rtx_equal_p (dest, XEXP (src, 1)) |
6391 | || rtx_equal_p (dest, get_last_value (XEXP (src, 1))) | |
6392 | || rtx_equal_p (get_last_value (dest), XEXP (src, 1)))) | |
230d793d | 6393 | { |
8999a12e | 6394 | assign = make_extraction (VOIDmode, dest, 0, XEXP (XEXP (src, 0), 1), |
230d793d | 6395 | 1, 1, 1, 0); |
dfbe1b2f | 6396 | return gen_rtx (SET, VOIDmode, assign, const1_rtx); |
230d793d RS |
6397 | } |
6398 | ||
dfbe1b2f RK |
6399 | /* The other case we handle is assignments into a constant-position |
6400 | field. They look like (ior (and DEST C1) OTHER). If C1 represents | |
6401 | a mask that has all one bits except for a group of zero bits and | |
6402 | OTHER is known to have zeros where C1 has ones, this is such an | |
6403 | assignment. Compute the position and length from C1. Shift OTHER | |
6404 | to the appropriate position, force it to the required mode, and | |
6405 | make the extraction. Check for the AND in both operands. */ | |
6406 | ||
6407 | if (GET_CODE (src) == IOR && GET_CODE (XEXP (src, 0)) == AND | |
6408 | && GET_CODE (XEXP (XEXP (src, 0), 1)) == CONST_INT | |
6409 | && (rtx_equal_p (XEXP (XEXP (src, 0), 0), dest) | |
6410 | || rtx_equal_p (XEXP (XEXP (src, 0), 0), get_last_value (dest)) | |
6411 | || rtx_equal_p (get_last_value (XEXP (XEXP (src, 0), 1)), dest))) | |
6412 | c1 = INTVAL (XEXP (XEXP (src, 0), 1)), other = XEXP (src, 1); | |
6413 | else if (GET_CODE (src) == IOR && GET_CODE (XEXP (src, 1)) == AND | |
6414 | && GET_CODE (XEXP (XEXP (src, 1), 1)) == CONST_INT | |
6415 | && (rtx_equal_p (XEXP (XEXP (src, 1), 0), dest) | |
6416 | || rtx_equal_p (XEXP (XEXP (src, 1), 0), get_last_value (dest)) | |
6417 | || rtx_equal_p (get_last_value (XEXP (XEXP (src, 1), 0)), | |
6418 | dest))) | |
6419 | c1 = INTVAL (XEXP (XEXP (src, 1), 1)), other = XEXP (src, 0); | |
6420 | else | |
6421 | return x; | |
230d793d | 6422 | |
c2f9f64e | 6423 | pos = get_pos_from_mask (c1 ^ GET_MODE_MASK (GET_MODE (dest)), &len); |
dfbe1b2f | 6424 | if (pos < 0 || pos + len > GET_MODE_BITSIZE (GET_MODE (dest)) |
ac49a949 | 6425 | || (GET_MODE_BITSIZE (GET_MODE (other)) <= HOST_BITS_PER_WIDE_INT |
951553af | 6426 | && (c1 & nonzero_bits (other, GET_MODE (other))) != 0)) |
dfbe1b2f | 6427 | return x; |
230d793d | 6428 | |
5f4f0e22 | 6429 | assign = make_extraction (VOIDmode, dest, pos, NULL_RTX, len, 1, 1, 0); |
230d793d | 6430 | |
dfbe1b2f RK |
6431 | /* The mode to use for the source is the mode of the assignment, or of |
6432 | what is inside a possible STRICT_LOW_PART. */ | |
6433 | mode = (GET_CODE (assign) == STRICT_LOW_PART | |
6434 | ? GET_MODE (XEXP (assign, 0)) : GET_MODE (assign)); | |
230d793d | 6435 | |
dfbe1b2f RK |
6436 | /* Shift OTHER right POS places and make it the source, restricting it |
6437 | to the proper length and mode. */ | |
230d793d | 6438 | |
5f4f0e22 CH |
6439 | src = force_to_mode (simplify_shift_const (NULL_RTX, LSHIFTRT, |
6440 | GET_MODE (src), other, pos), | |
6139ff20 RK |
6441 | mode, |
6442 | GET_MODE_BITSIZE (mode) >= HOST_BITS_PER_WIDE_INT | |
6443 | ? GET_MODE_MASK (mode) | |
6444 | : ((HOST_WIDE_INT) 1 << len) - 1, | |
e3d616e3 | 6445 | dest, 0); |
230d793d | 6446 | |
dfbe1b2f | 6447 | return gen_rtx_combine (SET, VOIDmode, assign, src); |
230d793d RS |
6448 | } |
6449 | \f | |
6450 | /* See if X is of the form (+ (* a c) (* b c)) and convert to (* (+ a b) c) | |
6451 | if so. */ | |
6452 | ||
6453 | static rtx | |
6454 | apply_distributive_law (x) | |
6455 | rtx x; | |
6456 | { | |
6457 | enum rtx_code code = GET_CODE (x); | |
6458 | rtx lhs, rhs, other; | |
6459 | rtx tem; | |
6460 | enum rtx_code inner_code; | |
6461 | ||
d8a8a4da RS |
6462 | /* Distributivity is not true for floating point. |
6463 | It can change the value. So don't do it. | |
6464 | -- rms and moshier@world.std.com. */ | |
3ad2180a | 6465 | if (FLOAT_MODE_P (GET_MODE (x))) |
d8a8a4da RS |
6466 | return x; |
6467 | ||
230d793d RS |
6468 | /* The outer operation can only be one of the following: */ |
6469 | if (code != IOR && code != AND && code != XOR | |
6470 | && code != PLUS && code != MINUS) | |
6471 | return x; | |
6472 | ||
6473 | lhs = XEXP (x, 0), rhs = XEXP (x, 1); | |
6474 | ||
dfbe1b2f | 6475 | /* If either operand is a primitive we can't do anything, so get out fast. */ |
230d793d | 6476 | if (GET_RTX_CLASS (GET_CODE (lhs)) == 'o' |
dfbe1b2f | 6477 | || GET_RTX_CLASS (GET_CODE (rhs)) == 'o') |
230d793d RS |
6478 | return x; |
6479 | ||
6480 | lhs = expand_compound_operation (lhs); | |
6481 | rhs = expand_compound_operation (rhs); | |
6482 | inner_code = GET_CODE (lhs); | |
6483 | if (inner_code != GET_CODE (rhs)) | |
6484 | return x; | |
6485 | ||
6486 | /* See if the inner and outer operations distribute. */ | |
6487 | switch (inner_code) | |
6488 | { | |
6489 | case LSHIFTRT: | |
6490 | case ASHIFTRT: | |
6491 | case AND: | |
6492 | case IOR: | |
6493 | /* These all distribute except over PLUS. */ | |
6494 | if (code == PLUS || code == MINUS) | |
6495 | return x; | |
6496 | break; | |
6497 | ||
6498 | case MULT: | |
6499 | if (code != PLUS && code != MINUS) | |
6500 | return x; | |
6501 | break; | |
6502 | ||
6503 | case ASHIFT: | |
45620ed4 | 6504 | /* This is also a multiply, so it distributes over everything. */ |
230d793d RS |
6505 | break; |
6506 | ||
6507 | case SUBREG: | |
dfbe1b2f RK |
6508 | /* Non-paradoxical SUBREGs distributes over all operations, provided |
6509 | the inner modes and word numbers are the same, this is an extraction | |
2b4bd1bc JW |
6510 | of a low-order part, we don't convert an fp operation to int or |
6511 | vice versa, and we would not be converting a single-word | |
dfbe1b2f | 6512 | operation into a multi-word operation. The latter test is not |
2b4bd1bc | 6513 | required, but it prevents generating unneeded multi-word operations. |
dfbe1b2f RK |
6514 | Some of the previous tests are redundant given the latter test, but |
6515 | are retained because they are required for correctness. | |
6516 | ||
6517 | We produce the result slightly differently in this case. */ | |
6518 | ||
6519 | if (GET_MODE (SUBREG_REG (lhs)) != GET_MODE (SUBREG_REG (rhs)) | |
6520 | || SUBREG_WORD (lhs) != SUBREG_WORD (rhs) | |
6521 | || ! subreg_lowpart_p (lhs) | |
2b4bd1bc JW |
6522 | || (GET_MODE_CLASS (GET_MODE (lhs)) |
6523 | != GET_MODE_CLASS (GET_MODE (SUBREG_REG (lhs)))) | |
dfbe1b2f RK |
6524 | || (GET_MODE_SIZE (GET_MODE (lhs)) |
6525 | < GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs)))) | |
6526 | || GET_MODE_SIZE (GET_MODE (SUBREG_REG (lhs))) > UNITS_PER_WORD) | |
230d793d RS |
6527 | return x; |
6528 | ||
6529 | tem = gen_binary (code, GET_MODE (SUBREG_REG (lhs)), | |
6530 | SUBREG_REG (lhs), SUBREG_REG (rhs)); | |
6531 | return gen_lowpart_for_combine (GET_MODE (x), tem); | |
6532 | ||
6533 | default: | |
6534 | return x; | |
6535 | } | |
6536 | ||
6537 | /* Set LHS and RHS to the inner operands (A and B in the example | |
6538 | above) and set OTHER to the common operand (C in the example). | |
6539 | These is only one way to do this unless the inner operation is | |
6540 | commutative. */ | |
6541 | if (GET_RTX_CLASS (inner_code) == 'c' | |
6542 | && rtx_equal_p (XEXP (lhs, 0), XEXP (rhs, 0))) | |
6543 | other = XEXP (lhs, 0), lhs = XEXP (lhs, 1), rhs = XEXP (rhs, 1); | |
6544 | else if (GET_RTX_CLASS (inner_code) == 'c' | |
6545 | && rtx_equal_p (XEXP (lhs, 0), XEXP (rhs, 1))) | |
6546 | other = XEXP (lhs, 0), lhs = XEXP (lhs, 1), rhs = XEXP (rhs, 0); | |
6547 | else if (GET_RTX_CLASS (inner_code) == 'c' | |
6548 | && rtx_equal_p (XEXP (lhs, 1), XEXP (rhs, 0))) | |
6549 | other = XEXP (lhs, 1), lhs = XEXP (lhs, 0), rhs = XEXP (rhs, 1); | |
6550 | else if (rtx_equal_p (XEXP (lhs, 1), XEXP (rhs, 1))) | |
6551 | other = XEXP (lhs, 1), lhs = XEXP (lhs, 0), rhs = XEXP (rhs, 0); | |
6552 | else | |
6553 | return x; | |
6554 | ||
6555 | /* Form the new inner operation, seeing if it simplifies first. */ | |
6556 | tem = gen_binary (code, GET_MODE (x), lhs, rhs); | |
6557 | ||
6558 | /* There is one exception to the general way of distributing: | |
6559 | (a ^ b) | (a ^ c) -> (~a) & (b ^ c) */ | |
6560 | if (code == XOR && inner_code == IOR) | |
6561 | { | |
6562 | inner_code = AND; | |
0c1c8ea6 | 6563 | other = gen_unary (NOT, GET_MODE (x), GET_MODE (x), other); |
230d793d RS |
6564 | } |
6565 | ||
6566 | /* We may be able to continuing distributing the result, so call | |
6567 | ourselves recursively on the inner operation before forming the | |
6568 | outer operation, which we return. */ | |
6569 | return gen_binary (inner_code, GET_MODE (x), | |
6570 | apply_distributive_law (tem), other); | |
6571 | } | |
6572 | \f | |
6573 | /* We have X, a logical `and' of VAROP with the constant CONSTOP, to be done | |
6574 | in MODE. | |
6575 | ||
6576 | Return an equivalent form, if different from X. Otherwise, return X. If | |
6577 | X is zero, we are to always construct the equivalent form. */ | |
6578 | ||
6579 | static rtx | |
6580 | simplify_and_const_int (x, mode, varop, constop) | |
6581 | rtx x; | |
6582 | enum machine_mode mode; | |
6583 | rtx varop; | |
5f4f0e22 | 6584 | unsigned HOST_WIDE_INT constop; |
230d793d | 6585 | { |
951553af | 6586 | unsigned HOST_WIDE_INT nonzero; |
42301240 | 6587 | int i; |
230d793d | 6588 | |
6139ff20 RK |
6589 | /* Simplify VAROP knowing that we will be only looking at some of the |
6590 | bits in it. */ | |
e3d616e3 | 6591 | varop = force_to_mode (varop, mode, constop, NULL_RTX, 0); |
230d793d | 6592 | |
6139ff20 RK |
6593 | /* If VAROP is a CLOBBER, we will fail so return it; if it is a |
6594 | CONST_INT, we are done. */ | |
6595 | if (GET_CODE (varop) == CLOBBER || GET_CODE (varop) == CONST_INT) | |
6596 | return varop; | |
230d793d | 6597 | |
fc06d7aa RK |
6598 | /* See what bits may be nonzero in VAROP. Unlike the general case of |
6599 | a call to nonzero_bits, here we don't care about bits outside | |
6600 | MODE. */ | |
6601 | ||
6602 | nonzero = nonzero_bits (varop, mode) & GET_MODE_MASK (mode); | |
230d793d RS |
6603 | |
6604 | /* Turn off all bits in the constant that are known to already be zero. | |
951553af | 6605 | Thus, if the AND isn't needed at all, we will have CONSTOP == NONZERO_BITS |
230d793d RS |
6606 | which is tested below. */ |
6607 | ||
951553af | 6608 | constop &= nonzero; |
230d793d RS |
6609 | |
6610 | /* If we don't have any bits left, return zero. */ | |
6611 | if (constop == 0) | |
6612 | return const0_rtx; | |
6613 | ||
42301240 RK |
6614 | /* If VAROP is a NEG of something known to be zero or 1 and CONSTOP is |
6615 | a power of two, we can replace this with a ASHIFT. */ | |
6616 | if (GET_CODE (varop) == NEG && nonzero_bits (XEXP (varop, 0), mode) == 1 | |
6617 | && (i = exact_log2 (constop)) >= 0) | |
6618 | return simplify_shift_const (NULL_RTX, ASHIFT, mode, XEXP (varop, 0), i); | |
6619 | ||
6139ff20 RK |
6620 | /* If VAROP is an IOR or XOR, apply the AND to both branches of the IOR |
6621 | or XOR, then try to apply the distributive law. This may eliminate | |
6622 | operations if either branch can be simplified because of the AND. | |
6623 | It may also make some cases more complex, but those cases probably | |
6624 | won't match a pattern either with or without this. */ | |
6625 | ||
6626 | if (GET_CODE (varop) == IOR || GET_CODE (varop) == XOR) | |
6627 | return | |
6628 | gen_lowpart_for_combine | |
6629 | (mode, | |
6630 | apply_distributive_law | |
6631 | (gen_binary (GET_CODE (varop), GET_MODE (varop), | |
6632 | simplify_and_const_int (NULL_RTX, GET_MODE (varop), | |
6633 | XEXP (varop, 0), constop), | |
6634 | simplify_and_const_int (NULL_RTX, GET_MODE (varop), | |
6635 | XEXP (varop, 1), constop)))); | |
6636 | ||
230d793d RS |
6637 | /* Get VAROP in MODE. Try to get a SUBREG if not. Don't make a new SUBREG |
6638 | if we already had one (just check for the simplest cases). */ | |
6639 | if (x && GET_CODE (XEXP (x, 0)) == SUBREG | |
6640 | && GET_MODE (XEXP (x, 0)) == mode | |
6641 | && SUBREG_REG (XEXP (x, 0)) == varop) | |
6642 | varop = XEXP (x, 0); | |
6643 | else | |
6644 | varop = gen_lowpart_for_combine (mode, varop); | |
6645 | ||
6646 | /* If we can't make the SUBREG, try to return what we were given. */ | |
6647 | if (GET_CODE (varop) == CLOBBER) | |
6648 | return x ? x : varop; | |
6649 | ||
6650 | /* If we are only masking insignificant bits, return VAROP. */ | |
951553af | 6651 | if (constop == nonzero) |
230d793d RS |
6652 | x = varop; |
6653 | ||
6654 | /* Otherwise, return an AND. See how much, if any, of X we can use. */ | |
6655 | else if (x == 0 || GET_CODE (x) != AND || GET_MODE (x) != mode) | |
6139ff20 | 6656 | x = gen_binary (AND, mode, varop, GEN_INT (constop)); |
230d793d RS |
6657 | |
6658 | else | |
6659 | { | |
6660 | if (GET_CODE (XEXP (x, 1)) != CONST_INT | |
6661 | || INTVAL (XEXP (x, 1)) != constop) | |
5f4f0e22 | 6662 | SUBST (XEXP (x, 1), GEN_INT (constop)); |
230d793d RS |
6663 | |
6664 | SUBST (XEXP (x, 0), varop); | |
6665 | } | |
6666 | ||
6667 | return x; | |
6668 | } | |
6669 | \f | |
6670 | /* Given an expression, X, compute which bits in X can be non-zero. | |
6671 | We don't care about bits outside of those defined in MODE. | |
6672 | ||
6673 | For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is | |
6674 | a shift, AND, or zero_extract, we can do better. */ | |
6675 | ||
5f4f0e22 | 6676 | static unsigned HOST_WIDE_INT |
951553af | 6677 | nonzero_bits (x, mode) |
230d793d RS |
6678 | rtx x; |
6679 | enum machine_mode mode; | |
6680 | { | |
951553af RK |
6681 | unsigned HOST_WIDE_INT nonzero = GET_MODE_MASK (mode); |
6682 | unsigned HOST_WIDE_INT inner_nz; | |
230d793d RS |
6683 | enum rtx_code code; |
6684 | int mode_width = GET_MODE_BITSIZE (mode); | |
6685 | rtx tem; | |
6686 | ||
1c75dfa4 RK |
6687 | /* For floating-point values, assume all bits are needed. */ |
6688 | if (FLOAT_MODE_P (GET_MODE (x)) || FLOAT_MODE_P (mode)) | |
6689 | return nonzero; | |
6690 | ||
230d793d RS |
6691 | /* If X is wider than MODE, use its mode instead. */ |
6692 | if (GET_MODE_BITSIZE (GET_MODE (x)) > mode_width) | |
6693 | { | |
6694 | mode = GET_MODE (x); | |
951553af | 6695 | nonzero = GET_MODE_MASK (mode); |
230d793d RS |
6696 | mode_width = GET_MODE_BITSIZE (mode); |
6697 | } | |
6698 | ||
5f4f0e22 | 6699 | if (mode_width > HOST_BITS_PER_WIDE_INT) |
230d793d RS |
6700 | /* Our only callers in this case look for single bit values. So |
6701 | just return the mode mask. Those tests will then be false. */ | |
951553af | 6702 | return nonzero; |
230d793d | 6703 | |
8baf60bb | 6704 | #ifndef WORD_REGISTER_OPERATIONS |
c6965c0f | 6705 | /* If MODE is wider than X, but both are a single word for both the host |
0840fd91 RK |
6706 | and target machines, we can compute this from which bits of the |
6707 | object might be nonzero in its own mode, taking into account the fact | |
6708 | that on many CISC machines, accessing an object in a wider mode | |
6709 | causes the high-order bits to become undefined. So they are | |
6710 | not known to be zero. */ | |
6711 | ||
6712 | if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode | |
6713 | && GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD | |
6714 | && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT | |
c6965c0f | 6715 | && GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (GET_MODE (x))) |
0840fd91 RK |
6716 | { |
6717 | nonzero &= nonzero_bits (x, GET_MODE (x)); | |
6718 | nonzero |= GET_MODE_MASK (mode) & ~ GET_MODE_MASK (GET_MODE (x)); | |
6719 | return nonzero; | |
6720 | } | |
6721 | #endif | |
6722 | ||
230d793d RS |
6723 | code = GET_CODE (x); |
6724 | switch (code) | |
6725 | { | |
6726 | case REG: | |
6727 | #ifdef STACK_BOUNDARY | |
6728 | /* If this is the stack pointer, we may know something about its | |
6729 | alignment. If PUSH_ROUNDING is defined, it is possible for the | |
6730 | stack to be momentarily aligned only to that amount, so we pick | |
6731 | the least alignment. */ | |
6732 | ||
6733 | if (x == stack_pointer_rtx) | |
6734 | { | |
6735 | int sp_alignment = STACK_BOUNDARY / BITS_PER_UNIT; | |
6736 | ||
6737 | #ifdef PUSH_ROUNDING | |
6738 | sp_alignment = MIN (PUSH_ROUNDING (1), sp_alignment); | |
6739 | #endif | |
6740 | ||
951553af | 6741 | return nonzero & ~ (sp_alignment - 1); |
230d793d RS |
6742 | } |
6743 | #endif | |
6744 | ||
55310dad RK |
6745 | /* If X is a register whose nonzero bits value is current, use it. |
6746 | Otherwise, if X is a register whose value we can find, use that | |
6747 | value. Otherwise, use the previously-computed global nonzero bits | |
6748 | for this register. */ | |
6749 | ||
6750 | if (reg_last_set_value[REGNO (x)] != 0 | |
6751 | && reg_last_set_mode[REGNO (x)] == mode | |
6752 | && (reg_n_sets[REGNO (x)] == 1 | |
6753 | || reg_last_set_label[REGNO (x)] == label_tick) | |
6754 | && INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid) | |
6755 | return reg_last_set_nonzero_bits[REGNO (x)]; | |
230d793d RS |
6756 | |
6757 | tem = get_last_value (x); | |
9afa3d54 | 6758 | |
230d793d | 6759 | if (tem) |
9afa3d54 RK |
6760 | { |
6761 | #ifdef SHORT_IMMEDIATES_SIGN_EXTEND | |
6762 | /* If X is narrower than MODE and TEM is a non-negative | |
6763 | constant that would appear negative in the mode of X, | |
6764 | sign-extend it for use in reg_nonzero_bits because some | |
6765 | machines (maybe most) will actually do the sign-extension | |
6766 | and this is the conservative approach. | |
6767 | ||
6768 | ??? For 2.5, try to tighten up the MD files in this regard | |
6769 | instead of this kludge. */ | |
6770 | ||
6771 | if (GET_MODE_BITSIZE (GET_MODE (x)) < mode_width | |
6772 | && GET_CODE (tem) == CONST_INT | |
6773 | && INTVAL (tem) > 0 | |
6774 | && 0 != (INTVAL (tem) | |
6775 | & ((HOST_WIDE_INT) 1 | |
9e69be8c | 6776 | << (GET_MODE_BITSIZE (GET_MODE (x)) - 1)))) |
9afa3d54 RK |
6777 | tem = GEN_INT (INTVAL (tem) |
6778 | | ((HOST_WIDE_INT) (-1) | |
6779 | << GET_MODE_BITSIZE (GET_MODE (x)))); | |
6780 | #endif | |
6781 | return nonzero_bits (tem, mode); | |
6782 | } | |
951553af RK |
6783 | else if (nonzero_sign_valid && reg_nonzero_bits[REGNO (x)]) |
6784 | return reg_nonzero_bits[REGNO (x)] & nonzero; | |
230d793d | 6785 | else |
951553af | 6786 | return nonzero; |
230d793d RS |
6787 | |
6788 | case CONST_INT: | |
9afa3d54 RK |
6789 | #ifdef SHORT_IMMEDIATES_SIGN_EXTEND |
6790 | /* If X is negative in MODE, sign-extend the value. */ | |
9e69be8c RK |
6791 | if (INTVAL (x) > 0 && mode_width < BITS_PER_WORD |
6792 | && 0 != (INTVAL (x) & ((HOST_WIDE_INT) 1 << (mode_width - 1)))) | |
6793 | return (INTVAL (x) | ((HOST_WIDE_INT) (-1) << mode_width)); | |
9afa3d54 RK |
6794 | #endif |
6795 | ||
230d793d RS |
6796 | return INTVAL (x); |
6797 | ||
230d793d | 6798 | case MEM: |
8baf60bb | 6799 | #ifdef LOAD_EXTEND_OP |
230d793d RS |
6800 | /* In many, if not most, RISC machines, reading a byte from memory |
6801 | zeros the rest of the register. Noticing that fact saves a lot | |
6802 | of extra zero-extends. */ | |
8baf60bb RK |
6803 | if (LOAD_EXTEND_OP (GET_MODE (x)) == ZERO_EXTEND) |
6804 | nonzero &= GET_MODE_MASK (GET_MODE (x)); | |
230d793d | 6805 | #endif |
8baf60bb | 6806 | break; |
230d793d | 6807 | |
230d793d RS |
6808 | case EQ: case NE: |
6809 | case GT: case GTU: | |
6810 | case LT: case LTU: | |
6811 | case GE: case GEU: | |
6812 | case LE: case LEU: | |
3f508eca | 6813 | |
c6965c0f RK |
6814 | /* If this produces an integer result, we know which bits are set. |
6815 | Code here used to clear bits outside the mode of X, but that is | |
6816 | now done above. */ | |
230d793d | 6817 | |
c6965c0f RK |
6818 | if (GET_MODE_CLASS (mode) == MODE_INT |
6819 | && mode_width <= HOST_BITS_PER_WIDE_INT) | |
6820 | nonzero = STORE_FLAG_VALUE; | |
230d793d | 6821 | break; |
230d793d | 6822 | |
230d793d | 6823 | case NEG: |
d0ab8cd3 RK |
6824 | if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) |
6825 | == GET_MODE_BITSIZE (GET_MODE (x))) | |
951553af | 6826 | nonzero = 1; |
230d793d RS |
6827 | |
6828 | if (GET_MODE_SIZE (GET_MODE (x)) < mode_width) | |
951553af | 6829 | nonzero |= (GET_MODE_MASK (mode) & ~ GET_MODE_MASK (GET_MODE (x))); |
230d793d | 6830 | break; |
d0ab8cd3 RK |
6831 | |
6832 | case ABS: | |
6833 | if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) | |
6834 | == GET_MODE_BITSIZE (GET_MODE (x))) | |
951553af | 6835 | nonzero = 1; |
d0ab8cd3 | 6836 | break; |
230d793d RS |
6837 | |
6838 | case TRUNCATE: | |
951553af | 6839 | nonzero &= (nonzero_bits (XEXP (x, 0), mode) & GET_MODE_MASK (mode)); |
230d793d RS |
6840 | break; |
6841 | ||
6842 | case ZERO_EXTEND: | |
951553af | 6843 | nonzero &= nonzero_bits (XEXP (x, 0), mode); |
230d793d | 6844 | if (GET_MODE (XEXP (x, 0)) != VOIDmode) |
951553af | 6845 | nonzero &= GET_MODE_MASK (GET_MODE (XEXP (x, 0))); |
230d793d RS |
6846 | break; |
6847 | ||
6848 | case SIGN_EXTEND: | |
6849 | /* If the sign bit is known clear, this is the same as ZERO_EXTEND. | |
6850 | Otherwise, show all the bits in the outer mode but not the inner | |
6851 | may be non-zero. */ | |
951553af | 6852 | inner_nz = nonzero_bits (XEXP (x, 0), mode); |
230d793d RS |
6853 | if (GET_MODE (XEXP (x, 0)) != VOIDmode) |
6854 | { | |
951553af RK |
6855 | inner_nz &= GET_MODE_MASK (GET_MODE (XEXP (x, 0))); |
6856 | if (inner_nz & | |
5f4f0e22 CH |
6857 | (((HOST_WIDE_INT) 1 |
6858 | << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1)))) | |
951553af | 6859 | inner_nz |= (GET_MODE_MASK (mode) |
230d793d RS |
6860 | & ~ GET_MODE_MASK (GET_MODE (XEXP (x, 0)))); |
6861 | } | |
6862 | ||
951553af | 6863 | nonzero &= inner_nz; |
230d793d RS |
6864 | break; |
6865 | ||
6866 | case AND: | |
951553af RK |
6867 | nonzero &= (nonzero_bits (XEXP (x, 0), mode) |
6868 | & nonzero_bits (XEXP (x, 1), mode)); | |
230d793d RS |
6869 | break; |
6870 | ||
d0ab8cd3 RK |
6871 | case XOR: case IOR: |
6872 | case UMIN: case UMAX: case SMIN: case SMAX: | |
951553af RK |
6873 | nonzero &= (nonzero_bits (XEXP (x, 0), mode) |
6874 | | nonzero_bits (XEXP (x, 1), mode)); | |
230d793d RS |
6875 | break; |
6876 | ||
6877 | case PLUS: case MINUS: | |
6878 | case MULT: | |
6879 | case DIV: case UDIV: | |
6880 | case MOD: case UMOD: | |
6881 | /* We can apply the rules of arithmetic to compute the number of | |
6882 | high- and low-order zero bits of these operations. We start by | |
6883 | computing the width (position of the highest-order non-zero bit) | |
6884 | and the number of low-order zero bits for each value. */ | |
6885 | { | |
951553af RK |
6886 | unsigned HOST_WIDE_INT nz0 = nonzero_bits (XEXP (x, 0), mode); |
6887 | unsigned HOST_WIDE_INT nz1 = nonzero_bits (XEXP (x, 1), mode); | |
6888 | int width0 = floor_log2 (nz0) + 1; | |
6889 | int width1 = floor_log2 (nz1) + 1; | |
6890 | int low0 = floor_log2 (nz0 & -nz0); | |
6891 | int low1 = floor_log2 (nz1 & -nz1); | |
6892 | int op0_maybe_minusp = (nz0 & ((HOST_WIDE_INT) 1 << (mode_width - 1))); | |
6893 | int op1_maybe_minusp = (nz1 & ((HOST_WIDE_INT) 1 << (mode_width - 1))); | |
230d793d RS |
6894 | int result_width = mode_width; |
6895 | int result_low = 0; | |
6896 | ||
6897 | switch (code) | |
6898 | { | |
6899 | case PLUS: | |
6900 | result_width = MAX (width0, width1) + 1; | |
6901 | result_low = MIN (low0, low1); | |
6902 | break; | |
6903 | case MINUS: | |
6904 | result_low = MIN (low0, low1); | |
6905 | break; | |
6906 | case MULT: | |
6907 | result_width = width0 + width1; | |
6908 | result_low = low0 + low1; | |
6909 | break; | |
6910 | case DIV: | |
6911 | if (! op0_maybe_minusp && ! op1_maybe_minusp) | |
6912 | result_width = width0; | |
6913 | break; | |
6914 | case UDIV: | |
6915 | result_width = width0; | |
6916 | break; | |
6917 | case MOD: | |
6918 | if (! op0_maybe_minusp && ! op1_maybe_minusp) | |
6919 | result_width = MIN (width0, width1); | |
6920 | result_low = MIN (low0, low1); | |
6921 | break; | |
6922 | case UMOD: | |
6923 | result_width = MIN (width0, width1); | |
6924 | result_low = MIN (low0, low1); | |
6925 | break; | |
6926 | } | |
6927 | ||
6928 | if (result_width < mode_width) | |
951553af | 6929 | nonzero &= ((HOST_WIDE_INT) 1 << result_width) - 1; |
230d793d RS |
6930 | |
6931 | if (result_low > 0) | |
951553af | 6932 | nonzero &= ~ (((HOST_WIDE_INT) 1 << result_low) - 1); |
230d793d RS |
6933 | } |
6934 | break; | |
6935 | ||
6936 | case ZERO_EXTRACT: | |
6937 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
5f4f0e22 | 6938 | && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) |
951553af | 6939 | nonzero &= ((HOST_WIDE_INT) 1 << INTVAL (XEXP (x, 1))) - 1; |
230d793d RS |
6940 | break; |
6941 | ||
6942 | case SUBREG: | |
c3c2cb37 RK |
6943 | /* If this is a SUBREG formed for a promoted variable that has |
6944 | been zero-extended, we know that at least the high-order bits | |
6945 | are zero, though others might be too. */ | |
6946 | ||
6947 | if (SUBREG_PROMOTED_VAR_P (x) && SUBREG_PROMOTED_UNSIGNED_P (x)) | |
951553af RK |
6948 | nonzero = (GET_MODE_MASK (GET_MODE (x)) |
6949 | & nonzero_bits (SUBREG_REG (x), GET_MODE (x))); | |
c3c2cb37 | 6950 | |
230d793d RS |
6951 | /* If the inner mode is a single word for both the host and target |
6952 | machines, we can compute this from which bits of the inner | |
951553af | 6953 | object might be nonzero. */ |
230d793d | 6954 | if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) <= BITS_PER_WORD |
5f4f0e22 CH |
6955 | && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) |
6956 | <= HOST_BITS_PER_WIDE_INT)) | |
230d793d | 6957 | { |
951553af | 6958 | nonzero &= nonzero_bits (SUBREG_REG (x), mode); |
8baf60bb RK |
6959 | |
6960 | #ifndef WORD_REGISTER_OPERATIONS | |
230d793d RS |
6961 | /* On many CISC machines, accessing an object in a wider mode |
6962 | causes the high-order bits to become undefined. So they are | |
6963 | not known to be zero. */ | |
6964 | if (GET_MODE_SIZE (GET_MODE (x)) | |
6965 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) | |
951553af RK |
6966 | nonzero |= (GET_MODE_MASK (GET_MODE (x)) |
6967 | & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x)))); | |
230d793d RS |
6968 | #endif |
6969 | } | |
6970 | break; | |
6971 | ||
6972 | case ASHIFTRT: | |
6973 | case LSHIFTRT: | |
6974 | case ASHIFT: | |
230d793d | 6975 | case ROTATE: |
951553af | 6976 | /* The nonzero bits are in two classes: any bits within MODE |
230d793d | 6977 | that aren't in GET_MODE (x) are always significant. The rest of the |
951553af | 6978 | nonzero bits are those that are significant in the operand of |
230d793d RS |
6979 | the shift when shifted the appropriate number of bits. This |
6980 | shows that high-order bits are cleared by the right shift and | |
6981 | low-order bits by left shifts. */ | |
6982 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
6983 | && INTVAL (XEXP (x, 1)) >= 0 | |
5f4f0e22 | 6984 | && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT) |
230d793d RS |
6985 | { |
6986 | enum machine_mode inner_mode = GET_MODE (x); | |
6987 | int width = GET_MODE_BITSIZE (inner_mode); | |
6988 | int count = INTVAL (XEXP (x, 1)); | |
5f4f0e22 | 6989 | unsigned HOST_WIDE_INT mode_mask = GET_MODE_MASK (inner_mode); |
951553af RK |
6990 | unsigned HOST_WIDE_INT op_nonzero = nonzero_bits (XEXP (x, 0), mode); |
6991 | unsigned HOST_WIDE_INT inner = op_nonzero & mode_mask; | |
5f4f0e22 | 6992 | unsigned HOST_WIDE_INT outer = 0; |
230d793d RS |
6993 | |
6994 | if (mode_width > width) | |
951553af | 6995 | outer = (op_nonzero & nonzero & ~ mode_mask); |
230d793d RS |
6996 | |
6997 | if (code == LSHIFTRT) | |
6998 | inner >>= count; | |
6999 | else if (code == ASHIFTRT) | |
7000 | { | |
7001 | inner >>= count; | |
7002 | ||
951553af | 7003 | /* If the sign bit may have been nonzero before the shift, we |
230d793d | 7004 | need to mark all the places it could have been copied to |
951553af | 7005 | by the shift as possibly nonzero. */ |
5f4f0e22 CH |
7006 | if (inner & ((HOST_WIDE_INT) 1 << (width - 1 - count))) |
7007 | inner |= (((HOST_WIDE_INT) 1 << count) - 1) << (width - count); | |
230d793d | 7008 | } |
45620ed4 | 7009 | else if (code == ASHIFT) |
230d793d RS |
7010 | inner <<= count; |
7011 | else | |
7012 | inner = ((inner << (count % width) | |
7013 | | (inner >> (width - (count % width)))) & mode_mask); | |
7014 | ||
951553af | 7015 | nonzero &= (outer | inner); |
230d793d RS |
7016 | } |
7017 | break; | |
7018 | ||
7019 | case FFS: | |
7020 | /* This is at most the number of bits in the mode. */ | |
951553af | 7021 | nonzero = ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width) + 1)) - 1; |
230d793d | 7022 | break; |
d0ab8cd3 RK |
7023 | |
7024 | case IF_THEN_ELSE: | |
951553af RK |
7025 | nonzero &= (nonzero_bits (XEXP (x, 1), mode) |
7026 | | nonzero_bits (XEXP (x, 2), mode)); | |
d0ab8cd3 | 7027 | break; |
230d793d RS |
7028 | } |
7029 | ||
951553af | 7030 | return nonzero; |
230d793d RS |
7031 | } |
7032 | \f | |
d0ab8cd3 | 7033 | /* Return the number of bits at the high-order end of X that are known to |
5109d49f RK |
7034 | be equal to the sign bit. X will be used in mode MODE; if MODE is |
7035 | VOIDmode, X will be used in its own mode. The returned value will always | |
7036 | be between 1 and the number of bits in MODE. */ | |
d0ab8cd3 RK |
7037 | |
7038 | static int | |
7039 | num_sign_bit_copies (x, mode) | |
7040 | rtx x; | |
7041 | enum machine_mode mode; | |
7042 | { | |
7043 | enum rtx_code code = GET_CODE (x); | |
7044 | int bitwidth; | |
7045 | int num0, num1, result; | |
951553af | 7046 | unsigned HOST_WIDE_INT nonzero; |
d0ab8cd3 RK |
7047 | rtx tem; |
7048 | ||
7049 | /* If we weren't given a mode, use the mode of X. If the mode is still | |
1c75dfa4 RK |
7050 | VOIDmode, we don't know anything. Likewise if one of the modes is |
7051 | floating-point. */ | |
d0ab8cd3 RK |
7052 | |
7053 | if (mode == VOIDmode) | |
7054 | mode = GET_MODE (x); | |
7055 | ||
1c75dfa4 | 7056 | if (mode == VOIDmode || FLOAT_MODE_P (mode) || FLOAT_MODE_P (GET_MODE (x))) |
6752e8d2 | 7057 | return 1; |
d0ab8cd3 RK |
7058 | |
7059 | bitwidth = GET_MODE_BITSIZE (mode); | |
7060 | ||
312def2e RK |
7061 | /* For a smaller object, just ignore the high bits. */ |
7062 | if (bitwidth < GET_MODE_BITSIZE (GET_MODE (x))) | |
7063 | return MAX (1, (num_sign_bit_copies (x, GET_MODE (x)) | |
7064 | - (GET_MODE_BITSIZE (GET_MODE (x)) - bitwidth))); | |
7065 | ||
0c314d1a RK |
7066 | #ifndef WORD_REGISTER_OPERATIONS |
7067 | /* If this machine does not do all register operations on the entire | |
7068 | register and MODE is wider than the mode of X, we can say nothing | |
7069 | at all about the high-order bits. */ | |
7070 | if (GET_MODE (x) != VOIDmode && bitwidth > GET_MODE_BITSIZE (GET_MODE (x))) | |
7071 | return 1; | |
7072 | #endif | |
7073 | ||
d0ab8cd3 RK |
7074 | switch (code) |
7075 | { | |
7076 | case REG: | |
55310dad RK |
7077 | |
7078 | if (reg_last_set_value[REGNO (x)] != 0 | |
7079 | && reg_last_set_mode[REGNO (x)] == mode | |
7080 | && (reg_n_sets[REGNO (x)] == 1 | |
7081 | || reg_last_set_label[REGNO (x)] == label_tick) | |
7082 | && INSN_CUID (reg_last_set[REGNO (x)]) < subst_low_cuid) | |
7083 | return reg_last_set_sign_bit_copies[REGNO (x)]; | |
d0ab8cd3 RK |
7084 | |
7085 | tem = get_last_value (x); | |
7086 | if (tem != 0) | |
7087 | return num_sign_bit_copies (tem, mode); | |
55310dad RK |
7088 | |
7089 | if (nonzero_sign_valid && reg_sign_bit_copies[REGNO (x)] != 0) | |
7090 | return reg_sign_bit_copies[REGNO (x)]; | |
d0ab8cd3 RK |
7091 | break; |
7092 | ||
457816e2 | 7093 | case MEM: |
8baf60bb | 7094 | #ifdef LOAD_EXTEND_OP |
457816e2 | 7095 | /* Some RISC machines sign-extend all loads of smaller than a word. */ |
8baf60bb RK |
7096 | if (LOAD_EXTEND_OP (GET_MODE (x)) == SIGN_EXTEND) |
7097 | return MAX (1, bitwidth - GET_MODE_BITSIZE (GET_MODE (x)) + 1); | |
457816e2 | 7098 | #endif |
8baf60bb | 7099 | break; |
457816e2 | 7100 | |
d0ab8cd3 RK |
7101 | case CONST_INT: |
7102 | /* If the constant is negative, take its 1's complement and remask. | |
7103 | Then see how many zero bits we have. */ | |
951553af | 7104 | nonzero = INTVAL (x) & GET_MODE_MASK (mode); |
ac49a949 | 7105 | if (bitwidth <= HOST_BITS_PER_WIDE_INT |
951553af RK |
7106 | && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) |
7107 | nonzero = (~ nonzero) & GET_MODE_MASK (mode); | |
d0ab8cd3 | 7108 | |
951553af | 7109 | return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1); |
d0ab8cd3 RK |
7110 | |
7111 | case SUBREG: | |
c3c2cb37 RK |
7112 | /* If this is a SUBREG for a promoted object that is sign-extended |
7113 | and we are looking at it in a wider mode, we know that at least the | |
7114 | high-order bits are known to be sign bit copies. */ | |
7115 | ||
7116 | if (SUBREG_PROMOTED_VAR_P (x) && ! SUBREG_PROMOTED_UNSIGNED_P (x)) | |
dc3e17ad RK |
7117 | return MAX (bitwidth - GET_MODE_BITSIZE (GET_MODE (x)) + 1, |
7118 | num_sign_bit_copies (SUBREG_REG (x), mode)); | |
c3c2cb37 | 7119 | |
d0ab8cd3 RK |
7120 | /* For a smaller object, just ignore the high bits. */ |
7121 | if (bitwidth <= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))) | |
7122 | { | |
7123 | num0 = num_sign_bit_copies (SUBREG_REG (x), VOIDmode); | |
7124 | return MAX (1, (num0 | |
7125 | - (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) | |
7126 | - bitwidth))); | |
7127 | } | |
457816e2 | 7128 | |
8baf60bb RK |
7129 | #ifdef WORD_REGISTER_OPERATIONS |
7130 | /* For paradoxical SUBREGs on machines where all register operations | |
7131 | affect the entire register, just look inside. Note that we are | |
7132 | passing MODE to the recursive call, so the number of sign bit copies | |
7133 | will remain relative to that mode, not the inner mode. */ | |
457816e2 RK |
7134 | |
7135 | if (GET_MODE_SIZE (GET_MODE (x)) | |
7136 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) | |
7137 | return num_sign_bit_copies (SUBREG_REG (x), mode); | |
7138 | #endif | |
d0ab8cd3 RK |
7139 | break; |
7140 | ||
7141 | case SIGN_EXTRACT: | |
7142 | if (GET_CODE (XEXP (x, 1)) == CONST_INT) | |
7143 | return MAX (1, bitwidth - INTVAL (XEXP (x, 1))); | |
7144 | break; | |
7145 | ||
7146 | case SIGN_EXTEND: | |
7147 | return (bitwidth - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) | |
7148 | + num_sign_bit_copies (XEXP (x, 0), VOIDmode)); | |
7149 | ||
7150 | case TRUNCATE: | |
7151 | /* For a smaller object, just ignore the high bits. */ | |
7152 | num0 = num_sign_bit_copies (XEXP (x, 0), VOIDmode); | |
7153 | return MAX (1, (num0 - (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) | |
7154 | - bitwidth))); | |
7155 | ||
7156 | case NOT: | |
7157 | return num_sign_bit_copies (XEXP (x, 0), mode); | |
7158 | ||
7159 | case ROTATE: case ROTATERT: | |
7160 | /* If we are rotating left by a number of bits less than the number | |
7161 | of sign bit copies, we can just subtract that amount from the | |
7162 | number. */ | |
7163 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
7164 | && INTVAL (XEXP (x, 1)) >= 0 && INTVAL (XEXP (x, 1)) < bitwidth) | |
7165 | { | |
7166 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7167 | return MAX (1, num0 - (code == ROTATE ? INTVAL (XEXP (x, 1)) | |
7168 | : bitwidth - INTVAL (XEXP (x, 1)))); | |
7169 | } | |
7170 | break; | |
7171 | ||
7172 | case NEG: | |
7173 | /* In general, this subtracts one sign bit copy. But if the value | |
7174 | is known to be positive, the number of sign bit copies is the | |
951553af RK |
7175 | same as that of the input. Finally, if the input has just one bit |
7176 | that might be nonzero, all the bits are copies of the sign bit. */ | |
7177 | nonzero = nonzero_bits (XEXP (x, 0), mode); | |
7178 | if (nonzero == 1) | |
d0ab8cd3 RK |
7179 | return bitwidth; |
7180 | ||
7181 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7182 | if (num0 > 1 | |
ac49a949 | 7183 | && bitwidth <= HOST_BITS_PER_WIDE_INT |
951553af | 7184 | && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero)) |
d0ab8cd3 RK |
7185 | num0--; |
7186 | ||
7187 | return num0; | |
7188 | ||
7189 | case IOR: case AND: case XOR: | |
7190 | case SMIN: case SMAX: case UMIN: case UMAX: | |
7191 | /* Logical operations will preserve the number of sign-bit copies. | |
7192 | MIN and MAX operations always return one of the operands. */ | |
7193 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7194 | num1 = num_sign_bit_copies (XEXP (x, 1), mode); | |
7195 | return MIN (num0, num1); | |
7196 | ||
7197 | case PLUS: case MINUS: | |
7198 | /* For addition and subtraction, we can have a 1-bit carry. However, | |
7199 | if we are subtracting 1 from a positive number, there will not | |
7200 | be such a carry. Furthermore, if the positive number is known to | |
7201 | be 0 or 1, we know the result is either -1 or 0. */ | |
7202 | ||
3e3ea975 | 7203 | if (code == PLUS && XEXP (x, 1) == constm1_rtx |
9295e6af | 7204 | && bitwidth <= HOST_BITS_PER_WIDE_INT) |
d0ab8cd3 | 7205 | { |
951553af RK |
7206 | nonzero = nonzero_bits (XEXP (x, 0), mode); |
7207 | if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero) == 0) | |
7208 | return (nonzero == 1 || nonzero == 0 ? bitwidth | |
7209 | : bitwidth - floor_log2 (nonzero) - 1); | |
d0ab8cd3 RK |
7210 | } |
7211 | ||
7212 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7213 | num1 = num_sign_bit_copies (XEXP (x, 1), mode); | |
7214 | return MAX (1, MIN (num0, num1) - 1); | |
7215 | ||
7216 | case MULT: | |
7217 | /* The number of bits of the product is the sum of the number of | |
7218 | bits of both terms. However, unless one of the terms if known | |
7219 | to be positive, we must allow for an additional bit since negating | |
7220 | a negative number can remove one sign bit copy. */ | |
7221 | ||
7222 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7223 | num1 = num_sign_bit_copies (XEXP (x, 1), mode); | |
7224 | ||
7225 | result = bitwidth - (bitwidth - num0) - (bitwidth - num1); | |
7226 | if (result > 0 | |
9295e6af | 7227 | && bitwidth <= HOST_BITS_PER_WIDE_INT |
951553af | 7228 | && ((nonzero_bits (XEXP (x, 0), mode) |
d0ab8cd3 | 7229 | & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) |
951553af | 7230 | && (nonzero_bits (XEXP (x, 1), mode) |
d0ab8cd3 RK |
7231 | & ((HOST_WIDE_INT) 1 << (bitwidth - 1)) != 0)) |
7232 | result--; | |
7233 | ||
7234 | return MAX (1, result); | |
7235 | ||
7236 | case UDIV: | |
7237 | /* The result must be <= the first operand. */ | |
7238 | return num_sign_bit_copies (XEXP (x, 0), mode); | |
7239 | ||
7240 | case UMOD: | |
7241 | /* The result must be <= the scond operand. */ | |
7242 | return num_sign_bit_copies (XEXP (x, 1), mode); | |
7243 | ||
7244 | case DIV: | |
7245 | /* Similar to unsigned division, except that we have to worry about | |
7246 | the case where the divisor is negative, in which case we have | |
7247 | to add 1. */ | |
7248 | result = num_sign_bit_copies (XEXP (x, 0), mode); | |
7249 | if (result > 1 | |
ac49a949 | 7250 | && bitwidth <= HOST_BITS_PER_WIDE_INT |
951553af | 7251 | && (nonzero_bits (XEXP (x, 1), mode) |
d0ab8cd3 RK |
7252 | & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) |
7253 | result --; | |
7254 | ||
7255 | return result; | |
7256 | ||
7257 | case MOD: | |
7258 | result = num_sign_bit_copies (XEXP (x, 1), mode); | |
7259 | if (result > 1 | |
ac49a949 | 7260 | && bitwidth <= HOST_BITS_PER_WIDE_INT |
951553af | 7261 | && (nonzero_bits (XEXP (x, 1), mode) |
d0ab8cd3 RK |
7262 | & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0) |
7263 | result --; | |
7264 | ||
7265 | return result; | |
7266 | ||
7267 | case ASHIFTRT: | |
7268 | /* Shifts by a constant add to the number of bits equal to the | |
7269 | sign bit. */ | |
7270 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7271 | if (GET_CODE (XEXP (x, 1)) == CONST_INT | |
7272 | && INTVAL (XEXP (x, 1)) > 0) | |
7273 | num0 = MIN (bitwidth, num0 + INTVAL (XEXP (x, 1))); | |
7274 | ||
7275 | return num0; | |
7276 | ||
7277 | case ASHIFT: | |
d0ab8cd3 RK |
7278 | /* Left shifts destroy copies. */ |
7279 | if (GET_CODE (XEXP (x, 1)) != CONST_INT | |
7280 | || INTVAL (XEXP (x, 1)) < 0 | |
7281 | || INTVAL (XEXP (x, 1)) >= bitwidth) | |
7282 | return 1; | |
7283 | ||
7284 | num0 = num_sign_bit_copies (XEXP (x, 0), mode); | |
7285 | return MAX (1, num0 - INTVAL (XEXP (x, 1))); | |
7286 | ||
7287 | case IF_THEN_ELSE: | |
7288 | num0 = num_sign_bit_copies (XEXP (x, 1), mode); | |
7289 | num1 = num_sign_bit_copies (XEXP (x, 2), mode); | |
7290 | return MIN (num0, num1); | |
7291 | ||
7292 | #if STORE_FLAG_VALUE == -1 | |
7293 | case EQ: case NE: case GE: case GT: case LE: case LT: | |
7294 | case GEU: case GTU: case LEU: case LTU: | |
7295 | return bitwidth; | |
7296 | #endif | |
7297 | } | |
7298 | ||
7299 | /* If we haven't been able to figure it out by one of the above rules, | |
7300 | see if some of the high-order bits are known to be zero. If so, | |
ac49a949 RS |
7301 | count those bits and return one less than that amount. If we can't |
7302 | safely compute the mask for this mode, always return BITWIDTH. */ | |
7303 | ||
7304 | if (bitwidth > HOST_BITS_PER_WIDE_INT) | |
6752e8d2 | 7305 | return 1; |
d0ab8cd3 | 7306 | |
951553af | 7307 | nonzero = nonzero_bits (x, mode); |
df6f4086 | 7308 | return (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1)) |
951553af | 7309 | ? 1 : bitwidth - floor_log2 (nonzero) - 1); |
d0ab8cd3 RK |
7310 | } |
7311 | \f | |
1a26b032 RK |
7312 | /* Return the number of "extended" bits there are in X, when interpreted |
7313 | as a quantity in MODE whose signedness is indicated by UNSIGNEDP. For | |
7314 | unsigned quantities, this is the number of high-order zero bits. | |
7315 | For signed quantities, this is the number of copies of the sign bit | |
7316 | minus 1. In both case, this function returns the number of "spare" | |
7317 | bits. For example, if two quantities for which this function returns | |
7318 | at least 1 are added, the addition is known not to overflow. | |
7319 | ||
7320 | This function will always return 0 unless called during combine, which | |
7321 | implies that it must be called from a define_split. */ | |
7322 | ||
7323 | int | |
7324 | extended_count (x, mode, unsignedp) | |
7325 | rtx x; | |
7326 | enum machine_mode mode; | |
7327 | int unsignedp; | |
7328 | { | |
951553af | 7329 | if (nonzero_sign_valid == 0) |
1a26b032 RK |
7330 | return 0; |
7331 | ||
7332 | return (unsignedp | |
ac49a949 RS |
7333 | ? (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT |
7334 | && (GET_MODE_BITSIZE (mode) - 1 | |
951553af | 7335 | - floor_log2 (nonzero_bits (x, mode)))) |
1a26b032 RK |
7336 | : num_sign_bit_copies (x, mode) - 1); |
7337 | } | |
7338 | \f | |
230d793d RS |
7339 | /* This function is called from `simplify_shift_const' to merge two |
7340 | outer operations. Specifically, we have already found that we need | |
7341 | to perform operation *POP0 with constant *PCONST0 at the outermost | |
7342 | position. We would now like to also perform OP1 with constant CONST1 | |
7343 | (with *POP0 being done last). | |
7344 | ||
7345 | Return 1 if we can do the operation and update *POP0 and *PCONST0 with | |
7346 | the resulting operation. *PCOMP_P is set to 1 if we would need to | |
7347 | complement the innermost operand, otherwise it is unchanged. | |
7348 | ||
7349 | MODE is the mode in which the operation will be done. No bits outside | |
7350 | the width of this mode matter. It is assumed that the width of this mode | |
5f4f0e22 | 7351 | is smaller than or equal to HOST_BITS_PER_WIDE_INT. |
230d793d RS |
7352 | |
7353 | If *POP0 or OP1 are NIL, it means no operation is required. Only NEG, PLUS, | |
7354 | IOR, XOR, and AND are supported. We may set *POP0 to SET if the proper | |
7355 | result is simply *PCONST0. | |
7356 | ||
7357 | If the resulting operation cannot be expressed as one operation, we | |
7358 | return 0 and do not change *POP0, *PCONST0, and *PCOMP_P. */ | |
7359 | ||
7360 | static int | |
7361 | merge_outer_ops (pop0, pconst0, op1, const1, mode, pcomp_p) | |
7362 | enum rtx_code *pop0; | |
5f4f0e22 | 7363 | HOST_WIDE_INT *pconst0; |
230d793d | 7364 | enum rtx_code op1; |
5f4f0e22 | 7365 | HOST_WIDE_INT const1; |
230d793d RS |
7366 | enum machine_mode mode; |
7367 | int *pcomp_p; | |
7368 | { | |
7369 | enum rtx_code op0 = *pop0; | |
5f4f0e22 | 7370 | HOST_WIDE_INT const0 = *pconst0; |
230d793d RS |
7371 | |
7372 | const0 &= GET_MODE_MASK (mode); | |
7373 | const1 &= GET_MODE_MASK (mode); | |
7374 | ||
7375 | /* If OP0 is an AND, clear unimportant bits in CONST1. */ | |
7376 | if (op0 == AND) | |
7377 | const1 &= const0; | |
7378 | ||
7379 | /* If OP0 or OP1 is NIL, this is easy. Similarly if they are the same or | |
7380 | if OP0 is SET. */ | |
7381 | ||
7382 | if (op1 == NIL || op0 == SET) | |
7383 | return 1; | |
7384 | ||
7385 | else if (op0 == NIL) | |
7386 | op0 = op1, const0 = const1; | |
7387 | ||
7388 | else if (op0 == op1) | |
7389 | { | |
7390 | switch (op0) | |
7391 | { | |
7392 | case AND: | |
7393 | const0 &= const1; | |
7394 | break; | |
7395 | case IOR: | |
7396 | const0 |= const1; | |
7397 | break; | |
7398 | case XOR: | |
7399 | const0 ^= const1; | |
7400 | break; | |
7401 | case PLUS: | |
7402 | const0 += const1; | |
7403 | break; | |
7404 | case NEG: | |
7405 | op0 = NIL; | |
7406 | break; | |
7407 | } | |
7408 | } | |
7409 | ||
7410 | /* Otherwise, if either is a PLUS or NEG, we can't do anything. */ | |
7411 | else if (op0 == PLUS || op1 == PLUS || op0 == NEG || op1 == NEG) | |
7412 | return 0; | |
7413 | ||
7414 | /* If the two constants aren't the same, we can't do anything. The | |
7415 | remaining six cases can all be done. */ | |
7416 | else if (const0 != const1) | |
7417 | return 0; | |
7418 | ||
7419 | else | |
7420 | switch (op0) | |
7421 | { | |
7422 | case IOR: | |
7423 | if (op1 == AND) | |
7424 | /* (a & b) | b == b */ | |
7425 | op0 = SET; | |
7426 | else /* op1 == XOR */ | |
7427 | /* (a ^ b) | b == a | b */ | |
7428 | ; | |
7429 | break; | |
7430 | ||
7431 | case XOR: | |
7432 | if (op1 == AND) | |
7433 | /* (a & b) ^ b == (~a) & b */ | |
7434 | op0 = AND, *pcomp_p = 1; | |
7435 | else /* op1 == IOR */ | |
7436 | /* (a | b) ^ b == a & ~b */ | |
7437 | op0 = AND, *pconst0 = ~ const0; | |
7438 | break; | |
7439 | ||
7440 | case AND: | |
7441 | if (op1 == IOR) | |
7442 | /* (a | b) & b == b */ | |
7443 | op0 = SET; | |
7444 | else /* op1 == XOR */ | |
7445 | /* (a ^ b) & b) == (~a) & b */ | |
7446 | *pcomp_p = 1; | |
7447 | break; | |
7448 | } | |
7449 | ||
7450 | /* Check for NO-OP cases. */ | |
7451 | const0 &= GET_MODE_MASK (mode); | |
7452 | if (const0 == 0 | |
7453 | && (op0 == IOR || op0 == XOR || op0 == PLUS)) | |
7454 | op0 = NIL; | |
7455 | else if (const0 == 0 && op0 == AND) | |
7456 | op0 = SET; | |
7457 | else if (const0 == GET_MODE_MASK (mode) && op0 == AND) | |
7458 | op0 = NIL; | |
7459 | ||
7460 | *pop0 = op0; | |
7461 | *pconst0 = const0; | |
7462 | ||
7463 | return 1; | |
7464 | } | |
7465 | \f | |
7466 | /* Simplify a shift of VAROP by COUNT bits. CODE says what kind of shift. | |
7467 | The result of the shift is RESULT_MODE. X, if non-zero, is an expression | |
7468 | that we started with. | |
7469 | ||
7470 | The shift is normally computed in the widest mode we find in VAROP, as | |
7471 | long as it isn't a different number of words than RESULT_MODE. Exceptions | |
7472 | are ASHIFTRT and ROTATE, which are always done in their original mode, */ | |
7473 | ||
7474 | static rtx | |
7475 | simplify_shift_const (x, code, result_mode, varop, count) | |
7476 | rtx x; | |
7477 | enum rtx_code code; | |
7478 | enum machine_mode result_mode; | |
7479 | rtx varop; | |
7480 | int count; | |
7481 | { | |
7482 | enum rtx_code orig_code = code; | |
7483 | int orig_count = count; | |
7484 | enum machine_mode mode = result_mode; | |
7485 | enum machine_mode shift_mode, tmode; | |
7486 | int mode_words | |
7487 | = (GET_MODE_SIZE (mode) + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD; | |
7488 | /* We form (outer_op (code varop count) (outer_const)). */ | |
7489 | enum rtx_code outer_op = NIL; | |
c4e861e8 | 7490 | HOST_WIDE_INT outer_const = 0; |
230d793d RS |
7491 | rtx const_rtx; |
7492 | int complement_p = 0; | |
7493 | rtx new; | |
7494 | ||
7495 | /* If we were given an invalid count, don't do anything except exactly | |
7496 | what was requested. */ | |
7497 | ||
7498 | if (count < 0 || count > GET_MODE_BITSIZE (mode)) | |
7499 | { | |
7500 | if (x) | |
7501 | return x; | |
7502 | ||
5f4f0e22 | 7503 | return gen_rtx (code, mode, varop, GEN_INT (count)); |
230d793d RS |
7504 | } |
7505 | ||
7506 | /* Unless one of the branches of the `if' in this loop does a `continue', | |
7507 | we will `break' the loop after the `if'. */ | |
7508 | ||
7509 | while (count != 0) | |
7510 | { | |
7511 | /* If we have an operand of (clobber (const_int 0)), just return that | |
7512 | value. */ | |
7513 | if (GET_CODE (varop) == CLOBBER) | |
7514 | return varop; | |
7515 | ||
7516 | /* If we discovered we had to complement VAROP, leave. Making a NOT | |
7517 | here would cause an infinite loop. */ | |
7518 | if (complement_p) | |
7519 | break; | |
7520 | ||
7521 | /* Convert ROTATETRT to ROTATE. */ | |
7522 | if (code == ROTATERT) | |
7523 | code = ROTATE, count = GET_MODE_BITSIZE (result_mode) - count; | |
7524 | ||
230d793d RS |
7525 | /* We need to determine what mode we will do the shift in. If the |
7526 | shift is a ASHIFTRT or ROTATE, we must always do it in the mode it | |
7527 | was originally done in. Otherwise, we can do it in MODE, the widest | |
7528 | mode encountered. */ | |
7529 | shift_mode = (code == ASHIFTRT || code == ROTATE ? result_mode : mode); | |
7530 | ||
7531 | /* Handle cases where the count is greater than the size of the mode | |
7532 | minus 1. For ASHIFT, use the size minus one as the count (this can | |
7533 | occur when simplifying (lshiftrt (ashiftrt ..))). For rotates, | |
7534 | take the count modulo the size. For other shifts, the result is | |
7535 | zero. | |
7536 | ||
7537 | Since these shifts are being produced by the compiler by combining | |
7538 | multiple operations, each of which are defined, we know what the | |
7539 | result is supposed to be. */ | |
7540 | ||
7541 | if (count > GET_MODE_BITSIZE (shift_mode) - 1) | |
7542 | { | |
7543 | if (code == ASHIFTRT) | |
7544 | count = GET_MODE_BITSIZE (shift_mode) - 1; | |
7545 | else if (code == ROTATE || code == ROTATERT) | |
7546 | count %= GET_MODE_BITSIZE (shift_mode); | |
7547 | else | |
7548 | { | |
7549 | /* We can't simply return zero because there may be an | |
7550 | outer op. */ | |
7551 | varop = const0_rtx; | |
7552 | count = 0; | |
7553 | break; | |
7554 | } | |
7555 | } | |
7556 | ||
7557 | /* Negative counts are invalid and should not have been made (a | |
7558 | programmer-specified negative count should have been handled | |
7559 | above). */ | |
7560 | else if (count < 0) | |
7561 | abort (); | |
7562 | ||
312def2e RK |
7563 | /* An arithmetic right shift of a quantity known to be -1 or 0 |
7564 | is a no-op. */ | |
7565 | if (code == ASHIFTRT | |
7566 | && (num_sign_bit_copies (varop, shift_mode) | |
7567 | == GET_MODE_BITSIZE (shift_mode))) | |
d0ab8cd3 | 7568 | { |
312def2e RK |
7569 | count = 0; |
7570 | break; | |
7571 | } | |
d0ab8cd3 | 7572 | |
312def2e RK |
7573 | /* If we are doing an arithmetic right shift and discarding all but |
7574 | the sign bit copies, this is equivalent to doing a shift by the | |
7575 | bitsize minus one. Convert it into that shift because it will often | |
7576 | allow other simplifications. */ | |
500c518b | 7577 | |
312def2e RK |
7578 | if (code == ASHIFTRT |
7579 | && (count + num_sign_bit_copies (varop, shift_mode) | |
7580 | >= GET_MODE_BITSIZE (shift_mode))) | |
7581 | count = GET_MODE_BITSIZE (shift_mode) - 1; | |
500c518b | 7582 | |
230d793d RS |
7583 | /* We simplify the tests below and elsewhere by converting |
7584 | ASHIFTRT to LSHIFTRT if we know the sign bit is clear. | |
7585 | `make_compound_operation' will convert it to a ASHIFTRT for | |
7586 | those machines (such as Vax) that don't have a LSHIFTRT. */ | |
5f4f0e22 | 7587 | if (GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT |
230d793d | 7588 | && code == ASHIFTRT |
951553af | 7589 | && ((nonzero_bits (varop, shift_mode) |
5f4f0e22 CH |
7590 | & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (shift_mode) - 1))) |
7591 | == 0)) | |
230d793d RS |
7592 | code = LSHIFTRT; |
7593 | ||
7594 | switch (GET_CODE (varop)) | |
7595 | { | |
7596 | case SIGN_EXTEND: | |
7597 | case ZERO_EXTEND: | |
7598 | case SIGN_EXTRACT: | |
7599 | case ZERO_EXTRACT: | |
7600 | new = expand_compound_operation (varop); | |
7601 | if (new != varop) | |
7602 | { | |
7603 | varop = new; | |
7604 | continue; | |
7605 | } | |
7606 | break; | |
7607 | ||
7608 | case MEM: | |
7609 | /* If we have (xshiftrt (mem ...) C) and C is MODE_WIDTH | |
7610 | minus the width of a smaller mode, we can do this with a | |
7611 | SIGN_EXTEND or ZERO_EXTEND from the narrower memory location. */ | |
7612 | if ((code == ASHIFTRT || code == LSHIFTRT) | |
7613 | && ! mode_dependent_address_p (XEXP (varop, 0)) | |
7614 | && ! MEM_VOLATILE_P (varop) | |
7615 | && (tmode = mode_for_size (GET_MODE_BITSIZE (mode) - count, | |
7616 | MODE_INT, 1)) != BLKmode) | |
7617 | { | |
7618 | #if BYTES_BIG_ENDIAN | |
7619 | new = gen_rtx (MEM, tmode, XEXP (varop, 0)); | |
7620 | #else | |
7621 | new = gen_rtx (MEM, tmode, | |
7622 | plus_constant (XEXP (varop, 0), | |
7623 | count / BITS_PER_UNIT)); | |
7624 | RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (varop); | |
7625 | MEM_VOLATILE_P (new) = MEM_VOLATILE_P (varop); | |
7626 | MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (varop); | |
7627 | #endif | |
7628 | varop = gen_rtx_combine (code == ASHIFTRT ? SIGN_EXTEND | |
7629 | : ZERO_EXTEND, mode, new); | |
7630 | count = 0; | |
7631 | continue; | |
7632 | } | |
7633 | break; | |
7634 | ||
7635 | case USE: | |
7636 | /* Similar to the case above, except that we can only do this if | |
7637 | the resulting mode is the same as that of the underlying | |
7638 | MEM and adjust the address depending on the *bits* endianness | |
7639 | because of the way that bit-field extract insns are defined. */ | |
7640 | if ((code == ASHIFTRT || code == LSHIFTRT) | |
7641 | && (tmode = mode_for_size (GET_MODE_BITSIZE (mode) - count, | |
7642 | MODE_INT, 1)) != BLKmode | |
7643 | && tmode == GET_MODE (XEXP (varop, 0))) | |
7644 | { | |
7645 | #if BITS_BIG_ENDIAN | |
7646 | new = XEXP (varop, 0); | |
7647 | #else | |
7648 | new = copy_rtx (XEXP (varop, 0)); | |
7649 | SUBST (XEXP (new, 0), | |
7650 | plus_constant (XEXP (new, 0), | |
7651 | count / BITS_PER_UNIT)); | |
7652 | #endif | |
7653 | ||
7654 | varop = gen_rtx_combine (code == ASHIFTRT ? SIGN_EXTEND | |
7655 | : ZERO_EXTEND, mode, new); | |
7656 | count = 0; | |
7657 | continue; | |
7658 | } | |
7659 | break; | |
7660 | ||
7661 | case SUBREG: | |
7662 | /* If VAROP is a SUBREG, strip it as long as the inner operand has | |
7663 | the same number of words as what we've seen so far. Then store | |
7664 | the widest mode in MODE. */ | |
f9e67232 RS |
7665 | if (subreg_lowpart_p (varop) |
7666 | && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop))) | |
7667 | > GET_MODE_SIZE (GET_MODE (varop))) | |
230d793d RS |
7668 | && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (varop))) |
7669 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
7670 | == mode_words)) | |
7671 | { | |
7672 | varop = SUBREG_REG (varop); | |
7673 | if (GET_MODE_SIZE (GET_MODE (varop)) > GET_MODE_SIZE (mode)) | |
7674 | mode = GET_MODE (varop); | |
7675 | continue; | |
7676 | } | |
7677 | break; | |
7678 | ||
7679 | case MULT: | |
7680 | /* Some machines use MULT instead of ASHIFT because MULT | |
7681 | is cheaper. But it is still better on those machines to | |
7682 | merge two shifts into one. */ | |
7683 | if (GET_CODE (XEXP (varop, 1)) == CONST_INT | |
7684 | && exact_log2 (INTVAL (XEXP (varop, 1))) >= 0) | |
7685 | { | |
7686 | varop = gen_binary (ASHIFT, GET_MODE (varop), XEXP (varop, 0), | |
5f4f0e22 | 7687 | GEN_INT (exact_log2 (INTVAL (XEXP (varop, 1)))));; |
230d793d RS |
7688 | continue; |
7689 | } | |
7690 | break; | |
7691 | ||
7692 | case UDIV: | |
7693 | /* Similar, for when divides are cheaper. */ | |
7694 | if (GET_CODE (XEXP (varop, 1)) == CONST_INT | |
7695 | && exact_log2 (INTVAL (XEXP (varop, 1))) >= 0) | |
7696 | { | |
7697 | varop = gen_binary (LSHIFTRT, GET_MODE (varop), XEXP (varop, 0), | |
5f4f0e22 | 7698 | GEN_INT (exact_log2 (INTVAL (XEXP (varop, 1))))); |
230d793d RS |
7699 | continue; |
7700 | } | |
7701 | break; | |
7702 | ||
7703 | case ASHIFTRT: | |
7704 | /* If we are extracting just the sign bit of an arithmetic right | |
7705 | shift, that shift is not needed. */ | |
7706 | if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1) | |
7707 | { | |
7708 | varop = XEXP (varop, 0); | |
7709 | continue; | |
7710 | } | |
7711 | ||
7712 | /* ... fall through ... */ | |
7713 | ||
7714 | case LSHIFTRT: | |
7715 | case ASHIFT: | |
230d793d RS |
7716 | case ROTATE: |
7717 | /* Here we have two nested shifts. The result is usually the | |
7718 | AND of a new shift with a mask. We compute the result below. */ | |
7719 | if (GET_CODE (XEXP (varop, 1)) == CONST_INT | |
7720 | && INTVAL (XEXP (varop, 1)) >= 0 | |
7721 | && INTVAL (XEXP (varop, 1)) < GET_MODE_BITSIZE (GET_MODE (varop)) | |
5f4f0e22 CH |
7722 | && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT |
7723 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) | |
230d793d RS |
7724 | { |
7725 | enum rtx_code first_code = GET_CODE (varop); | |
7726 | int first_count = INTVAL (XEXP (varop, 1)); | |
5f4f0e22 | 7727 | unsigned HOST_WIDE_INT mask; |
230d793d | 7728 | rtx mask_rtx; |
230d793d | 7729 | |
230d793d RS |
7730 | /* We have one common special case. We can't do any merging if |
7731 | the inner code is an ASHIFTRT of a smaller mode. However, if | |
7732 | we have (ashift:M1 (subreg:M1 (ashiftrt:M2 FOO C1) 0) C2) | |
7733 | with C2 == GET_MODE_BITSIZE (M1) - GET_MODE_BITSIZE (M2), | |
7734 | we can convert it to | |
7735 | (ashiftrt:M1 (ashift:M1 (and:M1 (subreg:M1 FOO 0 C2) C3) C1). | |
7736 | This simplifies certain SIGN_EXTEND operations. */ | |
7737 | if (code == ASHIFT && first_code == ASHIFTRT | |
7738 | && (GET_MODE_BITSIZE (result_mode) | |
7739 | - GET_MODE_BITSIZE (GET_MODE (varop))) == count) | |
7740 | { | |
7741 | /* C3 has the low-order C1 bits zero. */ | |
7742 | ||
5f4f0e22 CH |
7743 | mask = (GET_MODE_MASK (mode) |
7744 | & ~ (((HOST_WIDE_INT) 1 << first_count) - 1)); | |
230d793d | 7745 | |
5f4f0e22 | 7746 | varop = simplify_and_const_int (NULL_RTX, result_mode, |
230d793d | 7747 | XEXP (varop, 0), mask); |
5f4f0e22 | 7748 | varop = simplify_shift_const (NULL_RTX, ASHIFT, result_mode, |
230d793d RS |
7749 | varop, count); |
7750 | count = first_count; | |
7751 | code = ASHIFTRT; | |
7752 | continue; | |
7753 | } | |
7754 | ||
d0ab8cd3 RK |
7755 | /* If this was (ashiftrt (ashift foo C1) C2) and FOO has more |
7756 | than C1 high-order bits equal to the sign bit, we can convert | |
7757 | this to either an ASHIFT or a ASHIFTRT depending on the | |
7758 | two counts. | |
230d793d RS |
7759 | |
7760 | We cannot do this if VAROP's mode is not SHIFT_MODE. */ | |
7761 | ||
7762 | if (code == ASHIFTRT && first_code == ASHIFT | |
7763 | && GET_MODE (varop) == shift_mode | |
d0ab8cd3 RK |
7764 | && (num_sign_bit_copies (XEXP (varop, 0), shift_mode) |
7765 | > first_count)) | |
230d793d | 7766 | { |
d0ab8cd3 RK |
7767 | count -= first_count; |
7768 | if (count < 0) | |
7769 | count = - count, code = ASHIFT; | |
7770 | varop = XEXP (varop, 0); | |
7771 | continue; | |
230d793d RS |
7772 | } |
7773 | ||
7774 | /* There are some cases we can't do. If CODE is ASHIFTRT, | |
7775 | we can only do this if FIRST_CODE is also ASHIFTRT. | |
7776 | ||
7777 | We can't do the case when CODE is ROTATE and FIRST_CODE is | |
7778 | ASHIFTRT. | |
7779 | ||
7780 | If the mode of this shift is not the mode of the outer shift, | |
7781 | we can't do this if either shift is ASHIFTRT or ROTATE. | |
7782 | ||
7783 | Finally, we can't do any of these if the mode is too wide | |
7784 | unless the codes are the same. | |
7785 | ||
7786 | Handle the case where the shift codes are the same | |
7787 | first. */ | |
7788 | ||
7789 | if (code == first_code) | |
7790 | { | |
7791 | if (GET_MODE (varop) != result_mode | |
7792 | && (code == ASHIFTRT || code == ROTATE)) | |
7793 | break; | |
7794 | ||
7795 | count += first_count; | |
7796 | varop = XEXP (varop, 0); | |
7797 | continue; | |
7798 | } | |
7799 | ||
7800 | if (code == ASHIFTRT | |
7801 | || (code == ROTATE && first_code == ASHIFTRT) | |
5f4f0e22 | 7802 | || GET_MODE_BITSIZE (mode) > HOST_BITS_PER_WIDE_INT |
230d793d RS |
7803 | || (GET_MODE (varop) != result_mode |
7804 | && (first_code == ASHIFTRT || first_code == ROTATE | |
7805 | || code == ROTATE))) | |
7806 | break; | |
7807 | ||
7808 | /* To compute the mask to apply after the shift, shift the | |
951553af | 7809 | nonzero bits of the inner shift the same way the |
230d793d RS |
7810 | outer shift will. */ |
7811 | ||
951553af | 7812 | mask_rtx = GEN_INT (nonzero_bits (varop, GET_MODE (varop))); |
230d793d RS |
7813 | |
7814 | mask_rtx | |
7815 | = simplify_binary_operation (code, result_mode, mask_rtx, | |
5f4f0e22 | 7816 | GEN_INT (count)); |
230d793d RS |
7817 | |
7818 | /* Give up if we can't compute an outer operation to use. */ | |
7819 | if (mask_rtx == 0 | |
7820 | || GET_CODE (mask_rtx) != CONST_INT | |
7821 | || ! merge_outer_ops (&outer_op, &outer_const, AND, | |
7822 | INTVAL (mask_rtx), | |
7823 | result_mode, &complement_p)) | |
7824 | break; | |
7825 | ||
7826 | /* If the shifts are in the same direction, we add the | |
7827 | counts. Otherwise, we subtract them. */ | |
7828 | if ((code == ASHIFTRT || code == LSHIFTRT) | |
7829 | == (first_code == ASHIFTRT || first_code == LSHIFTRT)) | |
7830 | count += first_count; | |
7831 | else | |
7832 | count -= first_count; | |
7833 | ||
7834 | /* If COUNT is positive, the new shift is usually CODE, | |
7835 | except for the two exceptions below, in which case it is | |
7836 | FIRST_CODE. If the count is negative, FIRST_CODE should | |
7837 | always be used */ | |
7838 | if (count > 0 | |
7839 | && ((first_code == ROTATE && code == ASHIFT) | |
7840 | || (first_code == ASHIFTRT && code == LSHIFTRT))) | |
7841 | code = first_code; | |
7842 | else if (count < 0) | |
7843 | code = first_code, count = - count; | |
7844 | ||
7845 | varop = XEXP (varop, 0); | |
7846 | continue; | |
7847 | } | |
7848 | ||
7849 | /* If we have (A << B << C) for any shift, we can convert this to | |
7850 | (A << C << B). This wins if A is a constant. Only try this if | |
7851 | B is not a constant. */ | |
7852 | ||
7853 | else if (GET_CODE (varop) == code | |
7854 | && GET_CODE (XEXP (varop, 1)) != CONST_INT | |
7855 | && 0 != (new | |
7856 | = simplify_binary_operation (code, mode, | |
7857 | XEXP (varop, 0), | |
5f4f0e22 | 7858 | GEN_INT (count)))) |
230d793d RS |
7859 | { |
7860 | varop = gen_rtx_combine (code, mode, new, XEXP (varop, 1)); | |
7861 | count = 0; | |
7862 | continue; | |
7863 | } | |
7864 | break; | |
7865 | ||
7866 | case NOT: | |
7867 | /* Make this fit the case below. */ | |
7868 | varop = gen_rtx_combine (XOR, mode, XEXP (varop, 0), | |
5f4f0e22 | 7869 | GEN_INT (GET_MODE_MASK (mode))); |
230d793d RS |
7870 | continue; |
7871 | ||
7872 | case IOR: | |
7873 | case AND: | |
7874 | case XOR: | |
7875 | /* If we have (xshiftrt (ior (plus X (const_int -1)) X) C) | |
7876 | with C the size of VAROP - 1 and the shift is logical if | |
7877 | STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1, | |
7878 | we have an (le X 0) operation. If we have an arithmetic shift | |
7879 | and STORE_FLAG_VALUE is 1 or we have a logical shift with | |
7880 | STORE_FLAG_VALUE of -1, we have a (neg (le X 0)) operation. */ | |
7881 | ||
7882 | if (GET_CODE (varop) == IOR && GET_CODE (XEXP (varop, 0)) == PLUS | |
7883 | && XEXP (XEXP (varop, 0), 1) == constm1_rtx | |
7884 | && (STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) | |
7885 | && (code == LSHIFTRT || code == ASHIFTRT) | |
7886 | && count == GET_MODE_BITSIZE (GET_MODE (varop)) - 1 | |
7887 | && rtx_equal_p (XEXP (XEXP (varop, 0), 0), XEXP (varop, 1))) | |
7888 | { | |
7889 | count = 0; | |
7890 | varop = gen_rtx_combine (LE, GET_MODE (varop), XEXP (varop, 1), | |
7891 | const0_rtx); | |
7892 | ||
7893 | if (STORE_FLAG_VALUE == 1 ? code == ASHIFTRT : code == LSHIFTRT) | |
7894 | varop = gen_rtx_combine (NEG, GET_MODE (varop), varop); | |
7895 | ||
7896 | continue; | |
7897 | } | |
7898 | ||
7899 | /* If we have (shift (logical)), move the logical to the outside | |
7900 | to allow it to possibly combine with another logical and the | |
7901 | shift to combine with another shift. This also canonicalizes to | |
7902 | what a ZERO_EXTRACT looks like. Also, some machines have | |
7903 | (and (shift)) insns. */ | |
7904 | ||
7905 | if (GET_CODE (XEXP (varop, 1)) == CONST_INT | |
7906 | && (new = simplify_binary_operation (code, result_mode, | |
7907 | XEXP (varop, 1), | |
5f4f0e22 | 7908 | GEN_INT (count))) != 0 |
7d171a1e | 7909 | && GET_CODE(new) == CONST_INT |
230d793d RS |
7910 | && merge_outer_ops (&outer_op, &outer_const, GET_CODE (varop), |
7911 | INTVAL (new), result_mode, &complement_p)) | |
7912 | { | |
7913 | varop = XEXP (varop, 0); | |
7914 | continue; | |
7915 | } | |
7916 | ||
7917 | /* If we can't do that, try to simplify the shift in each arm of the | |
7918 | logical expression, make a new logical expression, and apply | |
7919 | the inverse distributive law. */ | |
7920 | { | |
00d4ca1c | 7921 | rtx lhs = simplify_shift_const (NULL_RTX, code, shift_mode, |
230d793d | 7922 | XEXP (varop, 0), count); |
00d4ca1c | 7923 | rtx rhs = simplify_shift_const (NULL_RTX, code, shift_mode, |
230d793d RS |
7924 | XEXP (varop, 1), count); |
7925 | ||
21a64bf1 | 7926 | varop = gen_binary (GET_CODE (varop), shift_mode, lhs, rhs); |
230d793d RS |
7927 | varop = apply_distributive_law (varop); |
7928 | ||
7929 | count = 0; | |
7930 | } | |
7931 | break; | |
7932 | ||
7933 | case EQ: | |
45620ed4 | 7934 | /* convert (lshiftrt (eq FOO 0) C) to (xor FOO 1) if STORE_FLAG_VALUE |
230d793d | 7935 | says that the sign bit can be tested, FOO has mode MODE, C is |
45620ed4 RK |
7936 | GET_MODE_BITSIZE (MODE) - 1, and FOO has only its low-order bit |
7937 | that may be nonzero. */ | |
7938 | if (code == LSHIFTRT | |
230d793d RS |
7939 | && XEXP (varop, 1) == const0_rtx |
7940 | && GET_MODE (XEXP (varop, 0)) == result_mode | |
7941 | && count == GET_MODE_BITSIZE (result_mode) - 1 | |
5f4f0e22 | 7942 | && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT |
230d793d | 7943 | && ((STORE_FLAG_VALUE |
5f4f0e22 | 7944 | & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (result_mode) - 1)))) |
951553af | 7945 | && nonzero_bits (XEXP (varop, 0), result_mode) == 1 |
5f4f0e22 CH |
7946 | && merge_outer_ops (&outer_op, &outer_const, XOR, |
7947 | (HOST_WIDE_INT) 1, result_mode, | |
7948 | &complement_p)) | |
230d793d RS |
7949 | { |
7950 | varop = XEXP (varop, 0); | |
7951 | count = 0; | |
7952 | continue; | |
7953 | } | |
7954 | break; | |
7955 | ||
7956 | case NEG: | |
d0ab8cd3 RK |
7957 | /* (lshiftrt (neg A) C) where A is either 0 or 1 and C is one less |
7958 | than the number of bits in the mode is equivalent to A. */ | |
7959 | if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1 | |
951553af | 7960 | && nonzero_bits (XEXP (varop, 0), result_mode) == 1) |
230d793d | 7961 | { |
d0ab8cd3 | 7962 | varop = XEXP (varop, 0); |
230d793d RS |
7963 | count = 0; |
7964 | continue; | |
7965 | } | |
7966 | ||
7967 | /* NEG commutes with ASHIFT since it is multiplication. Move the | |
7968 | NEG outside to allow shifts to combine. */ | |
7969 | if (code == ASHIFT | |
5f4f0e22 CH |
7970 | && merge_outer_ops (&outer_op, &outer_const, NEG, |
7971 | (HOST_WIDE_INT) 0, result_mode, | |
7972 | &complement_p)) | |
230d793d RS |
7973 | { |
7974 | varop = XEXP (varop, 0); | |
7975 | continue; | |
7976 | } | |
7977 | break; | |
7978 | ||
7979 | case PLUS: | |
d0ab8cd3 RK |
7980 | /* (lshiftrt (plus A -1) C) where A is either 0 or 1 and C |
7981 | is one less than the number of bits in the mode is | |
7982 | equivalent to (xor A 1). */ | |
230d793d RS |
7983 | if (code == LSHIFTRT && count == GET_MODE_BITSIZE (result_mode) - 1 |
7984 | && XEXP (varop, 1) == constm1_rtx | |
951553af | 7985 | && nonzero_bits (XEXP (varop, 0), result_mode) == 1 |
5f4f0e22 CH |
7986 | && merge_outer_ops (&outer_op, &outer_const, XOR, |
7987 | (HOST_WIDE_INT) 1, result_mode, | |
7988 | &complement_p)) | |
230d793d RS |
7989 | { |
7990 | count = 0; | |
7991 | varop = XEXP (varop, 0); | |
7992 | continue; | |
7993 | } | |
7994 | ||
3f508eca | 7995 | /* If we have (xshiftrt (plus FOO BAR) C), and the only bits |
951553af | 7996 | that might be nonzero in BAR are those being shifted out and those |
3f508eca RK |
7997 | bits are known zero in FOO, we can replace the PLUS with FOO. |
7998 | Similarly in the other operand order. This code occurs when | |
7999 | we are computing the size of a variable-size array. */ | |
8000 | ||
8001 | if ((code == ASHIFTRT || code == LSHIFTRT) | |
5f4f0e22 | 8002 | && count < HOST_BITS_PER_WIDE_INT |
951553af RK |
8003 | && nonzero_bits (XEXP (varop, 1), result_mode) >> count == 0 |
8004 | && (nonzero_bits (XEXP (varop, 1), result_mode) | |
8005 | & nonzero_bits (XEXP (varop, 0), result_mode)) == 0) | |
3f508eca RK |
8006 | { |
8007 | varop = XEXP (varop, 0); | |
8008 | continue; | |
8009 | } | |
8010 | else if ((code == ASHIFTRT || code == LSHIFTRT) | |
5f4f0e22 | 8011 | && count < HOST_BITS_PER_WIDE_INT |
ac49a949 | 8012 | && GET_MODE_BITSIZE (result_mode) <= HOST_BITS_PER_WIDE_INT |
951553af | 8013 | && 0 == (nonzero_bits (XEXP (varop, 0), result_mode) |
3f508eca | 8014 | >> count) |
951553af RK |
8015 | && 0 == (nonzero_bits (XEXP (varop, 0), result_mode) |
8016 | & nonzero_bits (XEXP (varop, 1), | |
3f508eca RK |
8017 | result_mode))) |
8018 | { | |
8019 | varop = XEXP (varop, 1); | |
8020 | continue; | |
8021 | } | |
8022 | ||
230d793d RS |
8023 | /* (ashift (plus foo C) N) is (plus (ashift foo N) C'). */ |
8024 | if (code == ASHIFT | |
8025 | && GET_CODE (XEXP (varop, 1)) == CONST_INT | |
8026 | && (new = simplify_binary_operation (ASHIFT, result_mode, | |
8027 | XEXP (varop, 1), | |
5f4f0e22 | 8028 | GEN_INT (count))) != 0 |
7d171a1e | 8029 | && GET_CODE(new) == CONST_INT |
230d793d RS |
8030 | && merge_outer_ops (&outer_op, &outer_const, PLUS, |
8031 | INTVAL (new), result_mode, &complement_p)) | |
8032 | { | |
8033 | varop = XEXP (varop, 0); | |
8034 | continue; | |
8035 | } | |
8036 | break; | |
8037 | ||
8038 | case MINUS: | |
8039 | /* If we have (xshiftrt (minus (ashiftrt X C)) X) C) | |
8040 | with C the size of VAROP - 1 and the shift is logical if | |
8041 | STORE_FLAG_VALUE is 1 and arithmetic if STORE_FLAG_VALUE is -1, | |
8042 | we have a (gt X 0) operation. If the shift is arithmetic with | |
8043 | STORE_FLAG_VALUE of 1 or logical with STORE_FLAG_VALUE == -1, | |
8044 | we have a (neg (gt X 0)) operation. */ | |
8045 | ||
8046 | if (GET_CODE (XEXP (varop, 0)) == ASHIFTRT | |
8047 | && count == GET_MODE_BITSIZE (GET_MODE (varop)) - 1 | |
8048 | && (STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1) | |
8049 | && (code == LSHIFTRT || code == ASHIFTRT) | |
8050 | && GET_CODE (XEXP (XEXP (varop, 0), 1)) == CONST_INT | |
8051 | && INTVAL (XEXP (XEXP (varop, 0), 1)) == count | |
8052 | && rtx_equal_p (XEXP (XEXP (varop, 0), 0), XEXP (varop, 1))) | |
8053 | { | |
8054 | count = 0; | |
8055 | varop = gen_rtx_combine (GT, GET_MODE (varop), XEXP (varop, 1), | |
8056 | const0_rtx); | |
8057 | ||
8058 | if (STORE_FLAG_VALUE == 1 ? code == ASHIFTRT : code == LSHIFTRT) | |
8059 | varop = gen_rtx_combine (NEG, GET_MODE (varop), varop); | |
8060 | ||
8061 | continue; | |
8062 | } | |
8063 | break; | |
8064 | } | |
8065 | ||
8066 | break; | |
8067 | } | |
8068 | ||
8069 | /* We need to determine what mode to do the shift in. If the shift is | |
8070 | a ASHIFTRT or ROTATE, we must always do it in the mode it was originally | |
8071 | done in. Otherwise, we can do it in MODE, the widest mode encountered. | |
8072 | The code we care about is that of the shift that will actually be done, | |
8073 | not the shift that was originally requested. */ | |
8074 | shift_mode = (code == ASHIFTRT || code == ROTATE ? result_mode : mode); | |
8075 | ||
8076 | /* We have now finished analyzing the shift. The result should be | |
8077 | a shift of type CODE with SHIFT_MODE shifting VAROP COUNT places. If | |
8078 | OUTER_OP is non-NIL, it is an operation that needs to be applied | |
8079 | to the result of the shift. OUTER_CONST is the relevant constant, | |
8080 | but we must turn off all bits turned off in the shift. | |
8081 | ||
8082 | If we were passed a value for X, see if we can use any pieces of | |
8083 | it. If not, make new rtx. */ | |
8084 | ||
8085 | if (x && GET_RTX_CLASS (GET_CODE (x)) == '2' | |
8086 | && GET_CODE (XEXP (x, 1)) == CONST_INT | |
8087 | && INTVAL (XEXP (x, 1)) == count) | |
8088 | const_rtx = XEXP (x, 1); | |
8089 | else | |
5f4f0e22 | 8090 | const_rtx = GEN_INT (count); |
230d793d RS |
8091 | |
8092 | if (x && GET_CODE (XEXP (x, 0)) == SUBREG | |
8093 | && GET_MODE (XEXP (x, 0)) == shift_mode | |
8094 | && SUBREG_REG (XEXP (x, 0)) == varop) | |
8095 | varop = XEXP (x, 0); | |
8096 | else if (GET_MODE (varop) != shift_mode) | |
8097 | varop = gen_lowpart_for_combine (shift_mode, varop); | |
8098 | ||
8099 | /* If we can't make the SUBREG, try to return what we were given. */ | |
8100 | if (GET_CODE (varop) == CLOBBER) | |
8101 | return x ? x : varop; | |
8102 | ||
8103 | new = simplify_binary_operation (code, shift_mode, varop, const_rtx); | |
8104 | if (new != 0) | |
8105 | x = new; | |
8106 | else | |
8107 | { | |
8108 | if (x == 0 || GET_CODE (x) != code || GET_MODE (x) != shift_mode) | |
8109 | x = gen_rtx_combine (code, shift_mode, varop, const_rtx); | |
8110 | ||
8111 | SUBST (XEXP (x, 0), varop); | |
8112 | SUBST (XEXP (x, 1), const_rtx); | |
8113 | } | |
8114 | ||
224eeff2 RK |
8115 | /* If we have an outer operation and we just made a shift, it is |
8116 | possible that we could have simplified the shift were it not | |
8117 | for the outer operation. So try to do the simplification | |
8118 | recursively. */ | |
8119 | ||
8120 | if (outer_op != NIL && GET_CODE (x) == code | |
8121 | && GET_CODE (XEXP (x, 1)) == CONST_INT) | |
8122 | x = simplify_shift_const (x, code, shift_mode, XEXP (x, 0), | |
8123 | INTVAL (XEXP (x, 1))); | |
8124 | ||
230d793d RS |
8125 | /* If we were doing a LSHIFTRT in a wider mode than it was originally, |
8126 | turn off all the bits that the shift would have turned off. */ | |
8127 | if (orig_code == LSHIFTRT && result_mode != shift_mode) | |
5f4f0e22 | 8128 | x = simplify_and_const_int (NULL_RTX, shift_mode, x, |
230d793d RS |
8129 | GET_MODE_MASK (result_mode) >> orig_count); |
8130 | ||
8131 | /* Do the remainder of the processing in RESULT_MODE. */ | |
8132 | x = gen_lowpart_for_combine (result_mode, x); | |
8133 | ||
8134 | /* If COMPLEMENT_P is set, we have to complement X before doing the outer | |
8135 | operation. */ | |
8136 | if (complement_p) | |
0c1c8ea6 | 8137 | x = gen_unary (NOT, result_mode, result_mode, x); |
230d793d RS |
8138 | |
8139 | if (outer_op != NIL) | |
8140 | { | |
5f4f0e22 | 8141 | if (GET_MODE_BITSIZE (result_mode) < HOST_BITS_PER_WIDE_INT) |
230d793d RS |
8142 | outer_const &= GET_MODE_MASK (result_mode); |
8143 | ||
8144 | if (outer_op == AND) | |
5f4f0e22 | 8145 | x = simplify_and_const_int (NULL_RTX, result_mode, x, outer_const); |
230d793d RS |
8146 | else if (outer_op == SET) |
8147 | /* This means that we have determined that the result is | |
8148 | equivalent to a constant. This should be rare. */ | |
5f4f0e22 | 8149 | x = GEN_INT (outer_const); |
230d793d | 8150 | else if (GET_RTX_CLASS (outer_op) == '1') |
0c1c8ea6 | 8151 | x = gen_unary (outer_op, result_mode, result_mode, x); |
230d793d | 8152 | else |
5f4f0e22 | 8153 | x = gen_binary (outer_op, result_mode, x, GEN_INT (outer_const)); |
230d793d RS |
8154 | } |
8155 | ||
8156 | return x; | |
8157 | } | |
8158 | \f | |
8159 | /* Like recog, but we receive the address of a pointer to a new pattern. | |
8160 | We try to match the rtx that the pointer points to. | |
8161 | If that fails, we may try to modify or replace the pattern, | |
8162 | storing the replacement into the same pointer object. | |
8163 | ||
8164 | Modifications include deletion or addition of CLOBBERs. | |
8165 | ||
8166 | PNOTES is a pointer to a location where any REG_UNUSED notes added for | |
8167 | the CLOBBERs are placed. | |
8168 | ||
8169 | The value is the final insn code from the pattern ultimately matched, | |
8170 | or -1. */ | |
8171 | ||
8172 | static int | |
8173 | recog_for_combine (pnewpat, insn, pnotes) | |
8174 | rtx *pnewpat; | |
8175 | rtx insn; | |
8176 | rtx *pnotes; | |
8177 | { | |
8178 | register rtx pat = *pnewpat; | |
8179 | int insn_code_number; | |
8180 | int num_clobbers_to_add = 0; | |
8181 | int i; | |
8182 | rtx notes = 0; | |
8183 | ||
974f4146 RK |
8184 | /* If PAT is a PARALLEL, check to see if it contains the CLOBBER |
8185 | we use to indicate that something didn't match. If we find such a | |
8186 | thing, force rejection. */ | |
d96023cf | 8187 | if (GET_CODE (pat) == PARALLEL) |
974f4146 | 8188 | for (i = XVECLEN (pat, 0) - 1; i >= 0; i--) |
d96023cf RK |
8189 | if (GET_CODE (XVECEXP (pat, 0, i)) == CLOBBER |
8190 | && XEXP (XVECEXP (pat, 0, i), 0) == const0_rtx) | |
974f4146 RK |
8191 | return -1; |
8192 | ||
230d793d RS |
8193 | /* Is the result of combination a valid instruction? */ |
8194 | insn_code_number = recog (pat, insn, &num_clobbers_to_add); | |
8195 | ||
8196 | /* If it isn't, there is the possibility that we previously had an insn | |
8197 | that clobbered some register as a side effect, but the combined | |
8198 | insn doesn't need to do that. So try once more without the clobbers | |
8199 | unless this represents an ASM insn. */ | |
8200 | ||
8201 | if (insn_code_number < 0 && ! check_asm_operands (pat) | |
8202 | && GET_CODE (pat) == PARALLEL) | |
8203 | { | |
8204 | int pos; | |
8205 | ||
8206 | for (pos = 0, i = 0; i < XVECLEN (pat, 0); i++) | |
8207 | if (GET_CODE (XVECEXP (pat, 0, i)) != CLOBBER) | |
8208 | { | |
8209 | if (i != pos) | |
8210 | SUBST (XVECEXP (pat, 0, pos), XVECEXP (pat, 0, i)); | |
8211 | pos++; | |
8212 | } | |
8213 | ||
8214 | SUBST_INT (XVECLEN (pat, 0), pos); | |
8215 | ||
8216 | if (pos == 1) | |
8217 | pat = XVECEXP (pat, 0, 0); | |
8218 | ||
8219 | insn_code_number = recog (pat, insn, &num_clobbers_to_add); | |
8220 | } | |
8221 | ||
8222 | /* If we had any clobbers to add, make a new pattern than contains | |
8223 | them. Then check to make sure that all of them are dead. */ | |
8224 | if (num_clobbers_to_add) | |
8225 | { | |
8226 | rtx newpat = gen_rtx (PARALLEL, VOIDmode, | |
8227 | gen_rtvec (GET_CODE (pat) == PARALLEL | |
8228 | ? XVECLEN (pat, 0) + num_clobbers_to_add | |
8229 | : num_clobbers_to_add + 1)); | |
8230 | ||
8231 | if (GET_CODE (pat) == PARALLEL) | |
8232 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
8233 | XVECEXP (newpat, 0, i) = XVECEXP (pat, 0, i); | |
8234 | else | |
8235 | XVECEXP (newpat, 0, 0) = pat; | |
8236 | ||
8237 | add_clobbers (newpat, insn_code_number); | |
8238 | ||
8239 | for (i = XVECLEN (newpat, 0) - num_clobbers_to_add; | |
8240 | i < XVECLEN (newpat, 0); i++) | |
8241 | { | |
8242 | if (GET_CODE (XEXP (XVECEXP (newpat, 0, i), 0)) == REG | |
8243 | && ! reg_dead_at_p (XEXP (XVECEXP (newpat, 0, i), 0), insn)) | |
8244 | return -1; | |
8245 | notes = gen_rtx (EXPR_LIST, REG_UNUSED, | |
8246 | XEXP (XVECEXP (newpat, 0, i), 0), notes); | |
8247 | } | |
8248 | pat = newpat; | |
8249 | } | |
8250 | ||
8251 | *pnewpat = pat; | |
8252 | *pnotes = notes; | |
8253 | ||
8254 | return insn_code_number; | |
8255 | } | |
8256 | \f | |
8257 | /* Like gen_lowpart but for use by combine. In combine it is not possible | |
8258 | to create any new pseudoregs. However, it is safe to create | |
8259 | invalid memory addresses, because combine will try to recognize | |
8260 | them and all they will do is make the combine attempt fail. | |
8261 | ||
8262 | If for some reason this cannot do its job, an rtx | |
8263 | (clobber (const_int 0)) is returned. | |
8264 | An insn containing that will not be recognized. */ | |
8265 | ||
8266 | #undef gen_lowpart | |
8267 | ||
8268 | static rtx | |
8269 | gen_lowpart_for_combine (mode, x) | |
8270 | enum machine_mode mode; | |
8271 | register rtx x; | |
8272 | { | |
8273 | rtx result; | |
8274 | ||
8275 | if (GET_MODE (x) == mode) | |
8276 | return x; | |
8277 | ||
eae957a8 RK |
8278 | /* We can only support MODE being wider than a word if X is a |
8279 | constant integer or has a mode the same size. */ | |
8280 | ||
8281 | if (GET_MODE_SIZE (mode) > UNITS_PER_WORD | |
8282 | && ! ((GET_MODE (x) == VOIDmode | |
8283 | && (GET_CODE (x) == CONST_INT | |
8284 | || GET_CODE (x) == CONST_DOUBLE)) | |
8285 | || GET_MODE_SIZE (GET_MODE (x)) == GET_MODE_SIZE (mode))) | |
230d793d RS |
8286 | return gen_rtx (CLOBBER, GET_MODE (x), const0_rtx); |
8287 | ||
8288 | /* X might be a paradoxical (subreg (mem)). In that case, gen_lowpart | |
8289 | won't know what to do. So we will strip off the SUBREG here and | |
8290 | process normally. */ | |
8291 | if (GET_CODE (x) == SUBREG && GET_CODE (SUBREG_REG (x)) == MEM) | |
8292 | { | |
8293 | x = SUBREG_REG (x); | |
8294 | if (GET_MODE (x) == mode) | |
8295 | return x; | |
8296 | } | |
8297 | ||
8298 | result = gen_lowpart_common (mode, x); | |
8299 | if (result) | |
8300 | return result; | |
8301 | ||
8302 | if (GET_CODE (x) == MEM) | |
8303 | { | |
8304 | register int offset = 0; | |
8305 | rtx new; | |
8306 | ||
8307 | /* Refuse to work on a volatile memory ref or one with a mode-dependent | |
8308 | address. */ | |
8309 | if (MEM_VOLATILE_P (x) || mode_dependent_address_p (XEXP (x, 0))) | |
8310 | return gen_rtx (CLOBBER, GET_MODE (x), const0_rtx); | |
8311 | ||
8312 | /* If we want to refer to something bigger than the original memref, | |
8313 | generate a perverse subreg instead. That will force a reload | |
8314 | of the original memref X. */ | |
8315 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (mode)) | |
8316 | return gen_rtx (SUBREG, mode, x, 0); | |
8317 | ||
8318 | #if WORDS_BIG_ENDIAN | |
8319 | offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD) | |
8320 | - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)); | |
8321 | #endif | |
8322 | #if BYTES_BIG_ENDIAN | |
8323 | /* Adjust the address so that the address-after-the-data | |
8324 | is unchanged. */ | |
8325 | offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)) | |
8326 | - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))); | |
8327 | #endif | |
8328 | new = gen_rtx (MEM, mode, plus_constant (XEXP (x, 0), offset)); | |
8329 | RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x); | |
8330 | MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x); | |
8331 | MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x); | |
8332 | return new; | |
8333 | } | |
8334 | ||
8335 | /* If X is a comparison operator, rewrite it in a new mode. This | |
8336 | probably won't match, but may allow further simplifications. */ | |
8337 | else if (GET_RTX_CLASS (GET_CODE (x)) == '<') | |
8338 | return gen_rtx_combine (GET_CODE (x), mode, XEXP (x, 0), XEXP (x, 1)); | |
8339 | ||
8340 | /* If we couldn't simplify X any other way, just enclose it in a | |
8341 | SUBREG. Normally, this SUBREG won't match, but some patterns may | |
a7c99304 | 8342 | include an explicit SUBREG or we may simplify it further in combine. */ |
230d793d | 8343 | else |
dfbe1b2f RK |
8344 | { |
8345 | int word = 0; | |
8346 | ||
8347 | if (WORDS_BIG_ENDIAN && GET_MODE_SIZE (GET_MODE (x)) > UNITS_PER_WORD) | |
8348 | word = ((GET_MODE_SIZE (GET_MODE (x)) | |
8349 | - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)) | |
8350 | / UNITS_PER_WORD); | |
8351 | return gen_rtx (SUBREG, mode, x, word); | |
8352 | } | |
230d793d RS |
8353 | } |
8354 | \f | |
8355 | /* Make an rtx expression. This is a subset of gen_rtx and only supports | |
8356 | expressions of 1, 2, or 3 operands, each of which are rtx expressions. | |
8357 | ||
8358 | If the identical expression was previously in the insn (in the undobuf), | |
8359 | it will be returned. Only if it is not found will a new expression | |
8360 | be made. */ | |
8361 | ||
8362 | /*VARARGS2*/ | |
8363 | static rtx | |
4f90e4a0 | 8364 | gen_rtx_combine VPROTO((enum rtx_code code, enum machine_mode mode, ...)) |
230d793d | 8365 | { |
4f90e4a0 | 8366 | #ifndef __STDC__ |
230d793d RS |
8367 | enum rtx_code code; |
8368 | enum machine_mode mode; | |
4f90e4a0 RK |
8369 | #endif |
8370 | va_list p; | |
230d793d RS |
8371 | int n_args; |
8372 | rtx args[3]; | |
8373 | int i, j; | |
8374 | char *fmt; | |
8375 | rtx rt; | |
8376 | ||
4f90e4a0 RK |
8377 | VA_START (p, mode); |
8378 | ||
8379 | #ifndef __STDC__ | |
230d793d RS |
8380 | code = va_arg (p, enum rtx_code); |
8381 | mode = va_arg (p, enum machine_mode); | |
4f90e4a0 RK |
8382 | #endif |
8383 | ||
230d793d RS |
8384 | n_args = GET_RTX_LENGTH (code); |
8385 | fmt = GET_RTX_FORMAT (code); | |
8386 | ||
8387 | if (n_args == 0 || n_args > 3) | |
8388 | abort (); | |
8389 | ||
8390 | /* Get each arg and verify that it is supposed to be an expression. */ | |
8391 | for (j = 0; j < n_args; j++) | |
8392 | { | |
8393 | if (*fmt++ != 'e') | |
8394 | abort (); | |
8395 | ||
8396 | args[j] = va_arg (p, rtx); | |
8397 | } | |
8398 | ||
8399 | /* See if this is in undobuf. Be sure we don't use objects that came | |
8400 | from another insn; this could produce circular rtl structures. */ | |
8401 | ||
8402 | for (i = previous_num_undos; i < undobuf.num_undo; i++) | |
8403 | if (!undobuf.undo[i].is_int | |
f5393ab9 RS |
8404 | && GET_CODE (undobuf.undo[i].old_contents.r) == code |
8405 | && GET_MODE (undobuf.undo[i].old_contents.r) == mode) | |
230d793d RS |
8406 | { |
8407 | for (j = 0; j < n_args; j++) | |
f5393ab9 | 8408 | if (XEXP (undobuf.undo[i].old_contents.r, j) != args[j]) |
230d793d RS |
8409 | break; |
8410 | ||
8411 | if (j == n_args) | |
f5393ab9 | 8412 | return undobuf.undo[i].old_contents.r; |
230d793d RS |
8413 | } |
8414 | ||
8415 | /* Otherwise make a new rtx. We know we have 1, 2, or 3 args. | |
8416 | Use rtx_alloc instead of gen_rtx because it's faster on RISC. */ | |
8417 | rt = rtx_alloc (code); | |
8418 | PUT_MODE (rt, mode); | |
8419 | XEXP (rt, 0) = args[0]; | |
8420 | if (n_args > 1) | |
8421 | { | |
8422 | XEXP (rt, 1) = args[1]; | |
8423 | if (n_args > 2) | |
8424 | XEXP (rt, 2) = args[2]; | |
8425 | } | |
8426 | return rt; | |
8427 | } | |
8428 | ||
8429 | /* These routines make binary and unary operations by first seeing if they | |
8430 | fold; if not, a new expression is allocated. */ | |
8431 | ||
8432 | static rtx | |
8433 | gen_binary (code, mode, op0, op1) | |
8434 | enum rtx_code code; | |
8435 | enum machine_mode mode; | |
8436 | rtx op0, op1; | |
8437 | { | |
8438 | rtx result; | |
1a26b032 RK |
8439 | rtx tem; |
8440 | ||
8441 | if (GET_RTX_CLASS (code) == 'c' | |
8442 | && (GET_CODE (op0) == CONST_INT | |
8443 | || (CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT))) | |
8444 | tem = op0, op0 = op1, op1 = tem; | |
230d793d RS |
8445 | |
8446 | if (GET_RTX_CLASS (code) == '<') | |
8447 | { | |
8448 | enum machine_mode op_mode = GET_MODE (op0); | |
9210df58 RK |
8449 | |
8450 | /* Strip the COMPARE from (REL_OP (compare X Y) 0) to get | |
8451 | just (REL_OP X Y). */ | |
8452 | if (GET_CODE (op0) == COMPARE && op1 == const0_rtx) | |
8453 | { | |
8454 | op1 = XEXP (op0, 1); | |
8455 | op0 = XEXP (op0, 0); | |
8456 | op_mode = GET_MODE (op0); | |
8457 | } | |
8458 | ||
230d793d RS |
8459 | if (op_mode == VOIDmode) |
8460 | op_mode = GET_MODE (op1); | |
8461 | result = simplify_relational_operation (code, op_mode, op0, op1); | |
8462 | } | |
8463 | else | |
8464 | result = simplify_binary_operation (code, mode, op0, op1); | |
8465 | ||
8466 | if (result) | |
8467 | return result; | |
8468 | ||
8469 | /* Put complex operands first and constants second. */ | |
8470 | if (GET_RTX_CLASS (code) == 'c' | |
8471 | && ((CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT) | |
8472 | || (GET_RTX_CLASS (GET_CODE (op0)) == 'o' | |
8473 | && GET_RTX_CLASS (GET_CODE (op1)) != 'o') | |
8474 | || (GET_CODE (op0) == SUBREG | |
8475 | && GET_RTX_CLASS (GET_CODE (SUBREG_REG (op0))) == 'o' | |
8476 | && GET_RTX_CLASS (GET_CODE (op1)) != 'o'))) | |
8477 | return gen_rtx_combine (code, mode, op1, op0); | |
8478 | ||
8479 | return gen_rtx_combine (code, mode, op0, op1); | |
8480 | } | |
8481 | ||
8482 | static rtx | |
0c1c8ea6 | 8483 | gen_unary (code, mode, op0_mode, op0) |
230d793d | 8484 | enum rtx_code code; |
0c1c8ea6 | 8485 | enum machine_mode mode, op0_mode; |
230d793d RS |
8486 | rtx op0; |
8487 | { | |
0c1c8ea6 | 8488 | rtx result = simplify_unary_operation (code, mode, op0, op0_mode); |
230d793d RS |
8489 | |
8490 | if (result) | |
8491 | return result; | |
8492 | ||
8493 | return gen_rtx_combine (code, mode, op0); | |
8494 | } | |
8495 | \f | |
8496 | /* Simplify a comparison between *POP0 and *POP1 where CODE is the | |
8497 | comparison code that will be tested. | |
8498 | ||
8499 | The result is a possibly different comparison code to use. *POP0 and | |
8500 | *POP1 may be updated. | |
8501 | ||
8502 | It is possible that we might detect that a comparison is either always | |
8503 | true or always false. However, we do not perform general constant | |
5089e22e | 8504 | folding in combine, so this knowledge isn't useful. Such tautologies |
230d793d RS |
8505 | should have been detected earlier. Hence we ignore all such cases. */ |
8506 | ||
8507 | static enum rtx_code | |
8508 | simplify_comparison (code, pop0, pop1) | |
8509 | enum rtx_code code; | |
8510 | rtx *pop0; | |
8511 | rtx *pop1; | |
8512 | { | |
8513 | rtx op0 = *pop0; | |
8514 | rtx op1 = *pop1; | |
8515 | rtx tem, tem1; | |
8516 | int i; | |
8517 | enum machine_mode mode, tmode; | |
8518 | ||
8519 | /* Try a few ways of applying the same transformation to both operands. */ | |
8520 | while (1) | |
8521 | { | |
3a19aabc RK |
8522 | #ifndef WORD_REGISTER_OPERATIONS |
8523 | /* The test below this one won't handle SIGN_EXTENDs on these machines, | |
8524 | so check specially. */ | |
8525 | if (code != GTU && code != GEU && code != LTU && code != LEU | |
8526 | && GET_CODE (op0) == ASHIFTRT && GET_CODE (op1) == ASHIFTRT | |
8527 | && GET_CODE (XEXP (op0, 0)) == ASHIFT | |
8528 | && GET_CODE (XEXP (op1, 0)) == ASHIFT | |
8529 | && GET_CODE (XEXP (XEXP (op0, 0), 0)) == SUBREG | |
8530 | && GET_CODE (XEXP (XEXP (op1, 0), 0)) == SUBREG | |
8531 | && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0))) | |
ad25ba17 | 8532 | == GET_MODE (SUBREG_REG (XEXP (XEXP (op1, 0), 0)))) |
3a19aabc RK |
8533 | && GET_CODE (XEXP (op0, 1)) == CONST_INT |
8534 | && GET_CODE (XEXP (op1, 1)) == CONST_INT | |
8535 | && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT | |
8536 | && GET_CODE (XEXP (XEXP (op1, 0), 1)) == CONST_INT | |
8537 | && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (op1, 1)) | |
8538 | && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (XEXP (op0, 0), 1)) | |
8539 | && INTVAL (XEXP (op0, 1)) == INTVAL (XEXP (XEXP (op1, 0), 1)) | |
8540 | && (INTVAL (XEXP (op0, 1)) | |
8541 | == (GET_MODE_BITSIZE (GET_MODE (op0)) | |
8542 | - (GET_MODE_BITSIZE | |
8543 | (GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0)))))))) | |
8544 | { | |
8545 | op0 = SUBREG_REG (XEXP (XEXP (op0, 0), 0)); | |
8546 | op1 = SUBREG_REG (XEXP (XEXP (op1, 0), 0)); | |
8547 | } | |
8548 | #endif | |
8549 | ||
230d793d RS |
8550 | /* If both operands are the same constant shift, see if we can ignore the |
8551 | shift. We can if the shift is a rotate or if the bits shifted out of | |
951553af | 8552 | this shift are known to be zero for both inputs and if the type of |
230d793d | 8553 | comparison is compatible with the shift. */ |
67232b23 RK |
8554 | if (GET_CODE (op0) == GET_CODE (op1) |
8555 | && GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT | |
8556 | && ((GET_CODE (op0) == ROTATE && (code == NE || code == EQ)) | |
45620ed4 | 8557 | || ((GET_CODE (op0) == LSHIFTRT || GET_CODE (op0) == ASHIFT) |
67232b23 RK |
8558 | && (code != GT && code != LT && code != GE && code != LE)) |
8559 | || (GET_CODE (op0) == ASHIFTRT | |
8560 | && (code != GTU && code != LTU | |
8561 | && code != GEU && code != GEU))) | |
8562 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
8563 | && INTVAL (XEXP (op0, 1)) >= 0 | |
8564 | && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT | |
8565 | && XEXP (op0, 1) == XEXP (op1, 1)) | |
230d793d RS |
8566 | { |
8567 | enum machine_mode mode = GET_MODE (op0); | |
5f4f0e22 | 8568 | unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); |
230d793d RS |
8569 | int shift_count = INTVAL (XEXP (op0, 1)); |
8570 | ||
8571 | if (GET_CODE (op0) == LSHIFTRT || GET_CODE (op0) == ASHIFTRT) | |
8572 | mask &= (mask >> shift_count) << shift_count; | |
45620ed4 | 8573 | else if (GET_CODE (op0) == ASHIFT) |
230d793d RS |
8574 | mask = (mask & (mask << shift_count)) >> shift_count; |
8575 | ||
951553af RK |
8576 | if ((nonzero_bits (XEXP (op0, 0), mode) & ~ mask) == 0 |
8577 | && (nonzero_bits (XEXP (op1, 0), mode) & ~ mask) == 0) | |
230d793d RS |
8578 | op0 = XEXP (op0, 0), op1 = XEXP (op1, 0); |
8579 | else | |
8580 | break; | |
8581 | } | |
8582 | ||
8583 | /* If both operands are AND's of a paradoxical SUBREG by constant, the | |
8584 | SUBREGs are of the same mode, and, in both cases, the AND would | |
8585 | be redundant if the comparison was done in the narrower mode, | |
8586 | do the comparison in the narrower mode (e.g., we are AND'ing with 1 | |
951553af RK |
8587 | and the operand's possibly nonzero bits are 0xffffff01; in that case |
8588 | if we only care about QImode, we don't need the AND). This case | |
8589 | occurs if the output mode of an scc insn is not SImode and | |
7e4dc511 RK |
8590 | STORE_FLAG_VALUE == 1 (e.g., the 386). |
8591 | ||
8592 | Similarly, check for a case where the AND's are ZERO_EXTEND | |
8593 | operations from some narrower mode even though a SUBREG is not | |
8594 | present. */ | |
230d793d RS |
8595 | |
8596 | else if (GET_CODE (op0) == AND && GET_CODE (op1) == AND | |
8597 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
7e4dc511 | 8598 | && GET_CODE (XEXP (op1, 1)) == CONST_INT) |
230d793d | 8599 | { |
7e4dc511 RK |
8600 | rtx inner_op0 = XEXP (op0, 0); |
8601 | rtx inner_op1 = XEXP (op1, 0); | |
8602 | HOST_WIDE_INT c0 = INTVAL (XEXP (op0, 1)); | |
8603 | HOST_WIDE_INT c1 = INTVAL (XEXP (op1, 1)); | |
8604 | int changed = 0; | |
8605 | ||
8606 | if (GET_CODE (inner_op0) == SUBREG && GET_CODE (inner_op1) == SUBREG | |
8607 | && (GET_MODE_SIZE (GET_MODE (inner_op0)) | |
8608 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (inner_op0)))) | |
8609 | && (GET_MODE (SUBREG_REG (inner_op0)) | |
8610 | == GET_MODE (SUBREG_REG (inner_op1))) | |
8611 | && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) | |
8612 | <= HOST_BITS_PER_WIDE_INT) | |
8613 | && (0 == (~c0) & nonzero_bits (SUBREG_REG (inner_op0), | |
8614 | GET_MODE (SUBREG_REG (op0)))) | |
8615 | && (0 == (~c1) & nonzero_bits (SUBREG_REG (inner_op1), | |
8616 | GET_MODE (SUBREG_REG (inner_op1))))) | |
8617 | { | |
8618 | op0 = SUBREG_REG (inner_op0); | |
8619 | op1 = SUBREG_REG (inner_op1); | |
8620 | ||
8621 | /* The resulting comparison is always unsigned since we masked | |
8622 | off the original sign bit. */ | |
8623 | code = unsigned_condition (code); | |
8624 | ||
8625 | changed = 1; | |
8626 | } | |
230d793d | 8627 | |
7e4dc511 RK |
8628 | else if (c0 == c1) |
8629 | for (tmode = GET_CLASS_NARROWEST_MODE | |
8630 | (GET_MODE_CLASS (GET_MODE (op0))); | |
8631 | tmode != GET_MODE (op0); tmode = GET_MODE_WIDER_MODE (tmode)) | |
8632 | if (c0 == GET_MODE_MASK (tmode)) | |
8633 | { | |
8634 | op0 = gen_lowpart_for_combine (tmode, inner_op0); | |
8635 | op1 = gen_lowpart_for_combine (tmode, inner_op1); | |
8636 | changed = 1; | |
8637 | break; | |
8638 | } | |
8639 | ||
8640 | if (! changed) | |
8641 | break; | |
230d793d | 8642 | } |
3a19aabc | 8643 | |
ad25ba17 RK |
8644 | /* If both operands are NOT, we can strip off the outer operation |
8645 | and adjust the comparison code for swapped operands; similarly for | |
8646 | NEG, except that this must be an equality comparison. */ | |
8647 | else if ((GET_CODE (op0) == NOT && GET_CODE (op1) == NOT) | |
8648 | || (GET_CODE (op0) == NEG && GET_CODE (op1) == NEG | |
8649 | && (code == EQ || code == NE))) | |
8650 | op0 = XEXP (op0, 0), op1 = XEXP (op1, 0), code = swap_condition (code); | |
3a19aabc | 8651 | |
230d793d RS |
8652 | else |
8653 | break; | |
8654 | } | |
8655 | ||
8656 | /* If the first operand is a constant, swap the operands and adjust the | |
8657 | comparison code appropriately. */ | |
8658 | if (CONSTANT_P (op0)) | |
8659 | { | |
8660 | tem = op0, op0 = op1, op1 = tem; | |
8661 | code = swap_condition (code); | |
8662 | } | |
8663 | ||
8664 | /* We now enter a loop during which we will try to simplify the comparison. | |
8665 | For the most part, we only are concerned with comparisons with zero, | |
8666 | but some things may really be comparisons with zero but not start | |
8667 | out looking that way. */ | |
8668 | ||
8669 | while (GET_CODE (op1) == CONST_INT) | |
8670 | { | |
8671 | enum machine_mode mode = GET_MODE (op0); | |
8672 | int mode_width = GET_MODE_BITSIZE (mode); | |
5f4f0e22 | 8673 | unsigned HOST_WIDE_INT mask = GET_MODE_MASK (mode); |
230d793d RS |
8674 | int equality_comparison_p; |
8675 | int sign_bit_comparison_p; | |
8676 | int unsigned_comparison_p; | |
5f4f0e22 | 8677 | HOST_WIDE_INT const_op; |
230d793d RS |
8678 | |
8679 | /* We only want to handle integral modes. This catches VOIDmode, | |
8680 | CCmode, and the floating-point modes. An exception is that we | |
8681 | can handle VOIDmode if OP0 is a COMPARE or a comparison | |
8682 | operation. */ | |
8683 | ||
8684 | if (GET_MODE_CLASS (mode) != MODE_INT | |
8685 | && ! (mode == VOIDmode | |
8686 | && (GET_CODE (op0) == COMPARE | |
8687 | || GET_RTX_CLASS (GET_CODE (op0)) == '<'))) | |
8688 | break; | |
8689 | ||
8690 | /* Get the constant we are comparing against and turn off all bits | |
8691 | not on in our mode. */ | |
8692 | const_op = INTVAL (op1); | |
5f4f0e22 | 8693 | if (mode_width <= HOST_BITS_PER_WIDE_INT) |
4803a34a | 8694 | const_op &= mask; |
230d793d RS |
8695 | |
8696 | /* If we are comparing against a constant power of two and the value | |
951553af | 8697 | being compared can only have that single bit nonzero (e.g., it was |
230d793d RS |
8698 | `and'ed with that bit), we can replace this with a comparison |
8699 | with zero. */ | |
8700 | if (const_op | |
8701 | && (code == EQ || code == NE || code == GE || code == GEU | |
8702 | || code == LT || code == LTU) | |
5f4f0e22 | 8703 | && mode_width <= HOST_BITS_PER_WIDE_INT |
230d793d | 8704 | && exact_log2 (const_op) >= 0 |
951553af | 8705 | && nonzero_bits (op0, mode) == const_op) |
230d793d RS |
8706 | { |
8707 | code = (code == EQ || code == GE || code == GEU ? NE : EQ); | |
8708 | op1 = const0_rtx, const_op = 0; | |
8709 | } | |
8710 | ||
d0ab8cd3 RK |
8711 | /* Similarly, if we are comparing a value known to be either -1 or |
8712 | 0 with -1, change it to the opposite comparison against zero. */ | |
8713 | ||
8714 | if (const_op == -1 | |
8715 | && (code == EQ || code == NE || code == GT || code == LE | |
8716 | || code == GEU || code == LTU) | |
8717 | && num_sign_bit_copies (op0, mode) == mode_width) | |
8718 | { | |
8719 | code = (code == EQ || code == LE || code == GEU ? NE : EQ); | |
8720 | op1 = const0_rtx, const_op = 0; | |
8721 | } | |
8722 | ||
230d793d | 8723 | /* Do some canonicalizations based on the comparison code. We prefer |
4803a34a RK |
8724 | comparisons against zero and then prefer equality comparisons. |
8725 | If we can reduce the size of a constant, we will do that too. */ | |
230d793d RS |
8726 | |
8727 | switch (code) | |
8728 | { | |
8729 | case LT: | |
4803a34a RK |
8730 | /* < C is equivalent to <= (C - 1) */ |
8731 | if (const_op > 0) | |
230d793d | 8732 | { |
4803a34a | 8733 | const_op -= 1; |
5f4f0e22 | 8734 | op1 = GEN_INT (const_op); |
230d793d RS |
8735 | code = LE; |
8736 | /* ... fall through to LE case below. */ | |
8737 | } | |
8738 | else | |
8739 | break; | |
8740 | ||
8741 | case LE: | |
4803a34a RK |
8742 | /* <= C is equivalent to < (C + 1); we do this for C < 0 */ |
8743 | if (const_op < 0) | |
8744 | { | |
8745 | const_op += 1; | |
5f4f0e22 | 8746 | op1 = GEN_INT (const_op); |
4803a34a RK |
8747 | code = LT; |
8748 | } | |
230d793d RS |
8749 | |
8750 | /* If we are doing a <= 0 comparison on a value known to have | |
8751 | a zero sign bit, we can replace this with == 0. */ | |
8752 | else if (const_op == 0 | |
5f4f0e22 | 8753 | && mode_width <= HOST_BITS_PER_WIDE_INT |
951553af | 8754 | && (nonzero_bits (op0, mode) |
5f4f0e22 | 8755 | & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0) |
230d793d RS |
8756 | code = EQ; |
8757 | break; | |
8758 | ||
8759 | case GE: | |
4803a34a RK |
8760 | /* >= C is equivalent to > (C - 1). */ |
8761 | if (const_op > 0) | |
230d793d | 8762 | { |
4803a34a | 8763 | const_op -= 1; |
5f4f0e22 | 8764 | op1 = GEN_INT (const_op); |
230d793d RS |
8765 | code = GT; |
8766 | /* ... fall through to GT below. */ | |
8767 | } | |
8768 | else | |
8769 | break; | |
8770 | ||
8771 | case GT: | |
4803a34a RK |
8772 | /* > C is equivalent to >= (C + 1); we do this for C < 0*/ |
8773 | if (const_op < 0) | |
8774 | { | |
8775 | const_op += 1; | |
5f4f0e22 | 8776 | op1 = GEN_INT (const_op); |
4803a34a RK |
8777 | code = GE; |
8778 | } | |
230d793d RS |
8779 | |
8780 | /* If we are doing a > 0 comparison on a value known to have | |
8781 | a zero sign bit, we can replace this with != 0. */ | |
8782 | else if (const_op == 0 | |
5f4f0e22 | 8783 | && mode_width <= HOST_BITS_PER_WIDE_INT |
951553af | 8784 | && (nonzero_bits (op0, mode) |
5f4f0e22 | 8785 | & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0) |
230d793d RS |
8786 | code = NE; |
8787 | break; | |
8788 | ||
230d793d | 8789 | case LTU: |
4803a34a RK |
8790 | /* < C is equivalent to <= (C - 1). */ |
8791 | if (const_op > 0) | |
8792 | { | |
8793 | const_op -= 1; | |
5f4f0e22 | 8794 | op1 = GEN_INT (const_op); |
4803a34a RK |
8795 | code = LEU; |
8796 | /* ... fall through ... */ | |
8797 | } | |
d0ab8cd3 RK |
8798 | |
8799 | /* (unsigned) < 0x80000000 is equivalent to >= 0. */ | |
8800 | else if (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1)) | |
8801 | { | |
8802 | const_op = 0, op1 = const0_rtx; | |
8803 | code = GE; | |
8804 | break; | |
8805 | } | |
4803a34a RK |
8806 | else |
8807 | break; | |
230d793d RS |
8808 | |
8809 | case LEU: | |
8810 | /* unsigned <= 0 is equivalent to == 0 */ | |
8811 | if (const_op == 0) | |
8812 | code = EQ; | |
d0ab8cd3 RK |
8813 | |
8814 | /* (unsigned) <= 0x7fffffff is equivalent to >= 0. */ | |
8815 | else if (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1) | |
8816 | { | |
8817 | const_op = 0, op1 = const0_rtx; | |
8818 | code = GE; | |
8819 | } | |
230d793d RS |
8820 | break; |
8821 | ||
4803a34a RK |
8822 | case GEU: |
8823 | /* >= C is equivalent to < (C - 1). */ | |
8824 | if (const_op > 1) | |
8825 | { | |
8826 | const_op -= 1; | |
5f4f0e22 | 8827 | op1 = GEN_INT (const_op); |
4803a34a RK |
8828 | code = GTU; |
8829 | /* ... fall through ... */ | |
8830 | } | |
d0ab8cd3 RK |
8831 | |
8832 | /* (unsigned) >= 0x80000000 is equivalent to < 0. */ | |
8833 | else if (const_op == (HOST_WIDE_INT) 1 << (mode_width - 1)) | |
8834 | { | |
8835 | const_op = 0, op1 = const0_rtx; | |
8836 | code = LT; | |
8837 | } | |
4803a34a RK |
8838 | else |
8839 | break; | |
8840 | ||
230d793d RS |
8841 | case GTU: |
8842 | /* unsigned > 0 is equivalent to != 0 */ | |
8843 | if (const_op == 0) | |
8844 | code = NE; | |
d0ab8cd3 RK |
8845 | |
8846 | /* (unsigned) > 0x7fffffff is equivalent to < 0. */ | |
8847 | else if (const_op == ((HOST_WIDE_INT) 1 << (mode_width - 1)) - 1) | |
8848 | { | |
8849 | const_op = 0, op1 = const0_rtx; | |
8850 | code = LT; | |
8851 | } | |
230d793d RS |
8852 | break; |
8853 | } | |
8854 | ||
8855 | /* Compute some predicates to simplify code below. */ | |
8856 | ||
8857 | equality_comparison_p = (code == EQ || code == NE); | |
8858 | sign_bit_comparison_p = ((code == LT || code == GE) && const_op == 0); | |
8859 | unsigned_comparison_p = (code == LTU || code == LEU || code == GTU | |
8860 | || code == LEU); | |
8861 | ||
6139ff20 RK |
8862 | /* If this is a sign bit comparison and we can do arithmetic in |
8863 | MODE, say that we will only be needing the sign bit of OP0. */ | |
8864 | if (sign_bit_comparison_p | |
8865 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) | |
8866 | op0 = force_to_mode (op0, mode, | |
8867 | ((HOST_WIDE_INT) 1 | |
8868 | << (GET_MODE_BITSIZE (mode) - 1)), | |
e3d616e3 | 8869 | NULL_RTX, 0); |
6139ff20 | 8870 | |
230d793d RS |
8871 | /* Now try cases based on the opcode of OP0. If none of the cases |
8872 | does a "continue", we exit this loop immediately after the | |
8873 | switch. */ | |
8874 | ||
8875 | switch (GET_CODE (op0)) | |
8876 | { | |
8877 | case ZERO_EXTRACT: | |
8878 | /* If we are extracting a single bit from a variable position in | |
8879 | a constant that has only a single bit set and are comparing it | |
8880 | with zero, we can convert this into an equality comparison | |
8881 | between the position and the location of the single bit. We can't | |
8882 | do this if bit endian and we don't have an extzv since we then | |
8883 | can't know what mode to use for the endianness adjustment. */ | |
8884 | ||
8885 | #if ! BITS_BIG_ENDIAN || defined (HAVE_extzv) | |
8886 | if (GET_CODE (XEXP (op0, 0)) == CONST_INT | |
8887 | && XEXP (op0, 1) == const1_rtx | |
8888 | && equality_comparison_p && const_op == 0 | |
8889 | && (i = exact_log2 (INTVAL (XEXP (op0, 0)))) >= 0) | |
8890 | { | |
8891 | #if BITS_BIG_ENDIAN | |
8892 | i = (GET_MODE_BITSIZE | |
8893 | (insn_operand_mode[(int) CODE_FOR_extzv][1]) - 1 - i); | |
8894 | #endif | |
8895 | ||
8896 | op0 = XEXP (op0, 2); | |
5f4f0e22 | 8897 | op1 = GEN_INT (i); |
230d793d RS |
8898 | const_op = i; |
8899 | ||
8900 | /* Result is nonzero iff shift count is equal to I. */ | |
8901 | code = reverse_condition (code); | |
8902 | continue; | |
8903 | } | |
8904 | #endif | |
8905 | ||
8906 | /* ... fall through ... */ | |
8907 | ||
8908 | case SIGN_EXTRACT: | |
8909 | tem = expand_compound_operation (op0); | |
8910 | if (tem != op0) | |
8911 | { | |
8912 | op0 = tem; | |
8913 | continue; | |
8914 | } | |
8915 | break; | |
8916 | ||
8917 | case NOT: | |
8918 | /* If testing for equality, we can take the NOT of the constant. */ | |
8919 | if (equality_comparison_p | |
8920 | && (tem = simplify_unary_operation (NOT, mode, op1, mode)) != 0) | |
8921 | { | |
8922 | op0 = XEXP (op0, 0); | |
8923 | op1 = tem; | |
8924 | continue; | |
8925 | } | |
8926 | ||
8927 | /* If just looking at the sign bit, reverse the sense of the | |
8928 | comparison. */ | |
8929 | if (sign_bit_comparison_p) | |
8930 | { | |
8931 | op0 = XEXP (op0, 0); | |
8932 | code = (code == GE ? LT : GE); | |
8933 | continue; | |
8934 | } | |
8935 | break; | |
8936 | ||
8937 | case NEG: | |
8938 | /* If testing for equality, we can take the NEG of the constant. */ | |
8939 | if (equality_comparison_p | |
8940 | && (tem = simplify_unary_operation (NEG, mode, op1, mode)) != 0) | |
8941 | { | |
8942 | op0 = XEXP (op0, 0); | |
8943 | op1 = tem; | |
8944 | continue; | |
8945 | } | |
8946 | ||
8947 | /* The remaining cases only apply to comparisons with zero. */ | |
8948 | if (const_op != 0) | |
8949 | break; | |
8950 | ||
8951 | /* When X is ABS or is known positive, | |
8952 | (neg X) is < 0 if and only if X != 0. */ | |
8953 | ||
8954 | if (sign_bit_comparison_p | |
8955 | && (GET_CODE (XEXP (op0, 0)) == ABS | |
5f4f0e22 | 8956 | || (mode_width <= HOST_BITS_PER_WIDE_INT |
951553af | 8957 | && (nonzero_bits (XEXP (op0, 0), mode) |
5f4f0e22 | 8958 | & ((HOST_WIDE_INT) 1 << (mode_width - 1))) == 0))) |
230d793d RS |
8959 | { |
8960 | op0 = XEXP (op0, 0); | |
8961 | code = (code == LT ? NE : EQ); | |
8962 | continue; | |
8963 | } | |
8964 | ||
3bed8141 RK |
8965 | /* If we have NEG of something whose two high-order bits are the |
8966 | same, we know that "(-a) < 0" is equivalent to "a > 0". */ | |
8967 | if (num_sign_bit_copies (op0, mode) >= 2) | |
230d793d RS |
8968 | { |
8969 | op0 = XEXP (op0, 0); | |
8970 | code = swap_condition (code); | |
8971 | continue; | |
8972 | } | |
8973 | break; | |
8974 | ||
8975 | case ROTATE: | |
8976 | /* If we are testing equality and our count is a constant, we | |
8977 | can perform the inverse operation on our RHS. */ | |
8978 | if (equality_comparison_p && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
8979 | && (tem = simplify_binary_operation (ROTATERT, mode, | |
8980 | op1, XEXP (op0, 1))) != 0) | |
8981 | { | |
8982 | op0 = XEXP (op0, 0); | |
8983 | op1 = tem; | |
8984 | continue; | |
8985 | } | |
8986 | ||
8987 | /* If we are doing a < 0 or >= 0 comparison, it means we are testing | |
8988 | a particular bit. Convert it to an AND of a constant of that | |
8989 | bit. This will be converted into a ZERO_EXTRACT. */ | |
8990 | if (const_op == 0 && sign_bit_comparison_p | |
8991 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
5f4f0e22 | 8992 | && mode_width <= HOST_BITS_PER_WIDE_INT) |
230d793d | 8993 | { |
5f4f0e22 CH |
8994 | op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), |
8995 | ((HOST_WIDE_INT) 1 | |
8996 | << (mode_width - 1 | |
8997 | - INTVAL (XEXP (op0, 1))))); | |
230d793d RS |
8998 | code = (code == LT ? NE : EQ); |
8999 | continue; | |
9000 | } | |
9001 | ||
9002 | /* ... fall through ... */ | |
9003 | ||
9004 | case ABS: | |
9005 | /* ABS is ignorable inside an equality comparison with zero. */ | |
9006 | if (const_op == 0 && equality_comparison_p) | |
9007 | { | |
9008 | op0 = XEXP (op0, 0); | |
9009 | continue; | |
9010 | } | |
9011 | break; | |
9012 | ||
9013 | ||
9014 | case SIGN_EXTEND: | |
9015 | /* Can simplify (compare (zero/sign_extend FOO) CONST) | |
9016 | to (compare FOO CONST) if CONST fits in FOO's mode and we | |
9017 | are either testing inequality or have an unsigned comparison | |
9018 | with ZERO_EXTEND or a signed comparison with SIGN_EXTEND. */ | |
9019 | if (! unsigned_comparison_p | |
9020 | && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) | |
5f4f0e22 CH |
9021 | <= HOST_BITS_PER_WIDE_INT) |
9022 | && ((unsigned HOST_WIDE_INT) const_op | |
9023 | < (((HOST_WIDE_INT) 1 | |
9024 | << (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) - 1))))) | |
230d793d RS |
9025 | { |
9026 | op0 = XEXP (op0, 0); | |
9027 | continue; | |
9028 | } | |
9029 | break; | |
9030 | ||
9031 | case SUBREG: | |
a687e897 RK |
9032 | /* Check for the case where we are comparing A - C1 with C2, |
9033 | both constants are smaller than 1/2 the maxium positive | |
9034 | value in MODE, and the comparison is equality or unsigned. | |
9035 | In that case, if A is either zero-extended to MODE or has | |
9036 | sufficient sign bits so that the high-order bit in MODE | |
9037 | is a copy of the sign in the inner mode, we can prove that it is | |
9038 | safe to do the operation in the wider mode. This simplifies | |
9039 | many range checks. */ | |
9040 | ||
9041 | if (mode_width <= HOST_BITS_PER_WIDE_INT | |
9042 | && subreg_lowpart_p (op0) | |
9043 | && GET_CODE (SUBREG_REG (op0)) == PLUS | |
9044 | && GET_CODE (XEXP (SUBREG_REG (op0), 1)) == CONST_INT | |
9045 | && INTVAL (XEXP (SUBREG_REG (op0), 1)) < 0 | |
9046 | && (- INTVAL (XEXP (SUBREG_REG (op0), 1)) | |
9047 | < GET_MODE_MASK (mode) / 2) | |
adb7a1cb | 9048 | && (unsigned HOST_WIDE_INT) const_op < GET_MODE_MASK (mode) / 2 |
951553af RK |
9049 | && (0 == (nonzero_bits (XEXP (SUBREG_REG (op0), 0), |
9050 | GET_MODE (SUBREG_REG (op0))) | |
a687e897 RK |
9051 | & ~ GET_MODE_MASK (mode)) |
9052 | || (num_sign_bit_copies (XEXP (SUBREG_REG (op0), 0), | |
9053 | GET_MODE (SUBREG_REG (op0))) | |
9054 | > (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) | |
9055 | - GET_MODE_BITSIZE (mode))))) | |
9056 | { | |
9057 | op0 = SUBREG_REG (op0); | |
9058 | continue; | |
9059 | } | |
9060 | ||
fe0cf571 RK |
9061 | /* If the inner mode is narrower and we are extracting the low part, |
9062 | we can treat the SUBREG as if it were a ZERO_EXTEND. */ | |
9063 | if (subreg_lowpart_p (op0) | |
89f1c7f2 RS |
9064 | && GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) < mode_width) |
9065 | /* Fall through */ ; | |
9066 | else | |
230d793d RS |
9067 | break; |
9068 | ||
9069 | /* ... fall through ... */ | |
9070 | ||
9071 | case ZERO_EXTEND: | |
9072 | if ((unsigned_comparison_p || equality_comparison_p) | |
9073 | && (GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0))) | |
5f4f0e22 CH |
9074 | <= HOST_BITS_PER_WIDE_INT) |
9075 | && ((unsigned HOST_WIDE_INT) const_op | |
230d793d RS |
9076 | < GET_MODE_MASK (GET_MODE (XEXP (op0, 0))))) |
9077 | { | |
9078 | op0 = XEXP (op0, 0); | |
9079 | continue; | |
9080 | } | |
9081 | break; | |
9082 | ||
9083 | case PLUS: | |
20fdd649 | 9084 | /* (eq (plus X A) B) -> (eq X (minus B A)). We can only do |
5089e22e | 9085 | this for equality comparisons due to pathological cases involving |
230d793d | 9086 | overflows. */ |
20fdd649 RK |
9087 | if (equality_comparison_p |
9088 | && 0 != (tem = simplify_binary_operation (MINUS, mode, | |
9089 | op1, XEXP (op0, 1)))) | |
230d793d RS |
9090 | { |
9091 | op0 = XEXP (op0, 0); | |
9092 | op1 = tem; | |
9093 | continue; | |
9094 | } | |
9095 | ||
9096 | /* (plus (abs X) (const_int -1)) is < 0 if and only if X == 0. */ | |
9097 | if (const_op == 0 && XEXP (op0, 1) == constm1_rtx | |
9098 | && GET_CODE (XEXP (op0, 0)) == ABS && sign_bit_comparison_p) | |
9099 | { | |
9100 | op0 = XEXP (XEXP (op0, 0), 0); | |
9101 | code = (code == LT ? EQ : NE); | |
9102 | continue; | |
9103 | } | |
9104 | break; | |
9105 | ||
9106 | case MINUS: | |
20fdd649 RK |
9107 | /* (eq (minus A B) C) -> (eq A (plus B C)) or |
9108 | (eq B (minus A C)), whichever simplifies. We can only do | |
9109 | this for equality comparisons due to pathological cases involving | |
9110 | overflows. */ | |
9111 | if (equality_comparison_p | |
9112 | && 0 != (tem = simplify_binary_operation (PLUS, mode, | |
9113 | XEXP (op0, 1), op1))) | |
9114 | { | |
9115 | op0 = XEXP (op0, 0); | |
9116 | op1 = tem; | |
9117 | continue; | |
9118 | } | |
9119 | ||
9120 | if (equality_comparison_p | |
9121 | && 0 != (tem = simplify_binary_operation (MINUS, mode, | |
9122 | XEXP (op0, 0), op1))) | |
9123 | { | |
9124 | op0 = XEXP (op0, 1); | |
9125 | op1 = tem; | |
9126 | continue; | |
9127 | } | |
9128 | ||
230d793d RS |
9129 | /* The sign bit of (minus (ashiftrt X C) X), where C is the number |
9130 | of bits in X minus 1, is one iff X > 0. */ | |
9131 | if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 0)) == ASHIFTRT | |
9132 | && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT | |
9133 | && INTVAL (XEXP (XEXP (op0, 0), 1)) == mode_width - 1 | |
9134 | && rtx_equal_p (XEXP (XEXP (op0, 0), 0), XEXP (op0, 1))) | |
9135 | { | |
9136 | op0 = XEXP (op0, 1); | |
9137 | code = (code == GE ? LE : GT); | |
9138 | continue; | |
9139 | } | |
9140 | break; | |
9141 | ||
9142 | case XOR: | |
9143 | /* (eq (xor A B) C) -> (eq A (xor B C)). This is a simplification | |
9144 | if C is zero or B is a constant. */ | |
9145 | if (equality_comparison_p | |
9146 | && 0 != (tem = simplify_binary_operation (XOR, mode, | |
9147 | XEXP (op0, 1), op1))) | |
9148 | { | |
9149 | op0 = XEXP (op0, 0); | |
9150 | op1 = tem; | |
9151 | continue; | |
9152 | } | |
9153 | break; | |
9154 | ||
9155 | case EQ: case NE: | |
9156 | case LT: case LTU: case LE: case LEU: | |
9157 | case GT: case GTU: case GE: case GEU: | |
9158 | /* We can't do anything if OP0 is a condition code value, rather | |
9159 | than an actual data value. */ | |
9160 | if (const_op != 0 | |
9161 | #ifdef HAVE_cc0 | |
9162 | || XEXP (op0, 0) == cc0_rtx | |
9163 | #endif | |
9164 | || GET_MODE_CLASS (GET_MODE (XEXP (op0, 0))) == MODE_CC) | |
9165 | break; | |
9166 | ||
9167 | /* Get the two operands being compared. */ | |
9168 | if (GET_CODE (XEXP (op0, 0)) == COMPARE) | |
9169 | tem = XEXP (XEXP (op0, 0), 0), tem1 = XEXP (XEXP (op0, 0), 1); | |
9170 | else | |
9171 | tem = XEXP (op0, 0), tem1 = XEXP (op0, 1); | |
9172 | ||
9173 | /* Check for the cases where we simply want the result of the | |
9174 | earlier test or the opposite of that result. */ | |
9175 | if (code == NE | |
9176 | || (code == EQ && reversible_comparison_p (op0)) | |
5f4f0e22 | 9177 | || (GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT |
3f508eca | 9178 | && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT |
230d793d | 9179 | && (STORE_FLAG_VALUE |
5f4f0e22 CH |
9180 | & (((HOST_WIDE_INT) 1 |
9181 | << (GET_MODE_BITSIZE (GET_MODE (op0)) - 1)))) | |
230d793d RS |
9182 | && (code == LT |
9183 | || (code == GE && reversible_comparison_p (op0))))) | |
9184 | { | |
9185 | code = (code == LT || code == NE | |
9186 | ? GET_CODE (op0) : reverse_condition (GET_CODE (op0))); | |
9187 | op0 = tem, op1 = tem1; | |
9188 | continue; | |
9189 | } | |
9190 | break; | |
9191 | ||
9192 | case IOR: | |
9193 | /* The sign bit of (ior (plus X (const_int -1)) X) is non-zero | |
9194 | iff X <= 0. */ | |
9195 | if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 0)) == PLUS | |
9196 | && XEXP (XEXP (op0, 0), 1) == constm1_rtx | |
9197 | && rtx_equal_p (XEXP (XEXP (op0, 0), 0), XEXP (op0, 1))) | |
9198 | { | |
9199 | op0 = XEXP (op0, 1); | |
9200 | code = (code == GE ? GT : LE); | |
9201 | continue; | |
9202 | } | |
9203 | break; | |
9204 | ||
9205 | case AND: | |
9206 | /* Convert (and (xshift 1 X) Y) to (and (lshiftrt Y X) 1). This | |
9207 | will be converted to a ZERO_EXTRACT later. */ | |
9208 | if (const_op == 0 && equality_comparison_p | |
45620ed4 | 9209 | && GET_CODE (XEXP (op0, 0)) == ASHIFT |
230d793d RS |
9210 | && XEXP (XEXP (op0, 0), 0) == const1_rtx) |
9211 | { | |
9212 | op0 = simplify_and_const_int | |
9213 | (op0, mode, gen_rtx_combine (LSHIFTRT, mode, | |
9214 | XEXP (op0, 1), | |
9215 | XEXP (XEXP (op0, 0), 1)), | |
5f4f0e22 | 9216 | (HOST_WIDE_INT) 1); |
230d793d RS |
9217 | continue; |
9218 | } | |
9219 | ||
9220 | /* If we are comparing (and (lshiftrt X C1) C2) for equality with | |
9221 | zero and X is a comparison and C1 and C2 describe only bits set | |
9222 | in STORE_FLAG_VALUE, we can compare with X. */ | |
9223 | if (const_op == 0 && equality_comparison_p | |
5f4f0e22 | 9224 | && mode_width <= HOST_BITS_PER_WIDE_INT |
230d793d RS |
9225 | && GET_CODE (XEXP (op0, 1)) == CONST_INT |
9226 | && GET_CODE (XEXP (op0, 0)) == LSHIFTRT | |
9227 | && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT | |
9228 | && INTVAL (XEXP (XEXP (op0, 0), 1)) >= 0 | |
5f4f0e22 | 9229 | && INTVAL (XEXP (XEXP (op0, 0), 1)) < HOST_BITS_PER_WIDE_INT) |
230d793d RS |
9230 | { |
9231 | mask = ((INTVAL (XEXP (op0, 1)) & GET_MODE_MASK (mode)) | |
9232 | << INTVAL (XEXP (XEXP (op0, 0), 1))); | |
9233 | if ((~ STORE_FLAG_VALUE & mask) == 0 | |
9234 | && (GET_RTX_CLASS (GET_CODE (XEXP (XEXP (op0, 0), 0))) == '<' | |
9235 | || ((tem = get_last_value (XEXP (XEXP (op0, 0), 0))) != 0 | |
9236 | && GET_RTX_CLASS (GET_CODE (tem)) == '<'))) | |
9237 | { | |
9238 | op0 = XEXP (XEXP (op0, 0), 0); | |
9239 | continue; | |
9240 | } | |
9241 | } | |
9242 | ||
9243 | /* If we are doing an equality comparison of an AND of a bit equal | |
9244 | to the sign bit, replace this with a LT or GE comparison of | |
9245 | the underlying value. */ | |
9246 | if (equality_comparison_p | |
9247 | && const_op == 0 | |
9248 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
5f4f0e22 | 9249 | && mode_width <= HOST_BITS_PER_WIDE_INT |
230d793d | 9250 | && ((INTVAL (XEXP (op0, 1)) & GET_MODE_MASK (mode)) |
5f4f0e22 | 9251 | == (HOST_WIDE_INT) 1 << (mode_width - 1))) |
230d793d RS |
9252 | { |
9253 | op0 = XEXP (op0, 0); | |
9254 | code = (code == EQ ? GE : LT); | |
9255 | continue; | |
9256 | } | |
9257 | ||
9258 | /* If this AND operation is really a ZERO_EXTEND from a narrower | |
9259 | mode, the constant fits within that mode, and this is either an | |
9260 | equality or unsigned comparison, try to do this comparison in | |
9261 | the narrower mode. */ | |
9262 | if ((equality_comparison_p || unsigned_comparison_p) | |
9263 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9264 | && (i = exact_log2 ((INTVAL (XEXP (op0, 1)) | |
9265 | & GET_MODE_MASK (mode)) | |
9266 | + 1)) >= 0 | |
9267 | && const_op >> i == 0 | |
9268 | && (tmode = mode_for_size (i, MODE_INT, 1)) != BLKmode) | |
9269 | { | |
9270 | op0 = gen_lowpart_for_combine (tmode, XEXP (op0, 0)); | |
9271 | continue; | |
9272 | } | |
9273 | break; | |
9274 | ||
9275 | case ASHIFT: | |
45620ed4 | 9276 | /* If we have (compare (ashift FOO N) (const_int C)) and |
230d793d | 9277 | the high order N bits of FOO (N+1 if an inequality comparison) |
951553af | 9278 | are known to be zero, we can do this by comparing FOO with C |
230d793d RS |
9279 | shifted right N bits so long as the low-order N bits of C are |
9280 | zero. */ | |
9281 | if (GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9282 | && INTVAL (XEXP (op0, 1)) >= 0 | |
9283 | && ((INTVAL (XEXP (op0, 1)) + ! equality_comparison_p) | |
5f4f0e22 CH |
9284 | < HOST_BITS_PER_WIDE_INT) |
9285 | && ((const_op | |
34785d05 | 9286 | & (((HOST_WIDE_INT) 1 << INTVAL (XEXP (op0, 1))) - 1)) == 0) |
5f4f0e22 | 9287 | && mode_width <= HOST_BITS_PER_WIDE_INT |
951553af | 9288 | && (nonzero_bits (XEXP (op0, 0), mode) |
230d793d RS |
9289 | & ~ (mask >> (INTVAL (XEXP (op0, 1)) |
9290 | + ! equality_comparison_p))) == 0) | |
9291 | { | |
9292 | const_op >>= INTVAL (XEXP (op0, 1)); | |
5f4f0e22 | 9293 | op1 = GEN_INT (const_op); |
230d793d RS |
9294 | op0 = XEXP (op0, 0); |
9295 | continue; | |
9296 | } | |
9297 | ||
dfbe1b2f | 9298 | /* If we are doing a sign bit comparison, it means we are testing |
230d793d | 9299 | a particular bit. Convert it to the appropriate AND. */ |
dfbe1b2f | 9300 | if (sign_bit_comparison_p && GET_CODE (XEXP (op0, 1)) == CONST_INT |
5f4f0e22 | 9301 | && mode_width <= HOST_BITS_PER_WIDE_INT) |
230d793d | 9302 | { |
5f4f0e22 CH |
9303 | op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), |
9304 | ((HOST_WIDE_INT) 1 | |
9305 | << (mode_width - 1 | |
9306 | - INTVAL (XEXP (op0, 1))))); | |
230d793d RS |
9307 | code = (code == LT ? NE : EQ); |
9308 | continue; | |
9309 | } | |
dfbe1b2f RK |
9310 | |
9311 | /* If this an equality comparison with zero and we are shifting | |
9312 | the low bit to the sign bit, we can convert this to an AND of the | |
9313 | low-order bit. */ | |
9314 | if (const_op == 0 && equality_comparison_p | |
9315 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9316 | && INTVAL (XEXP (op0, 1)) == mode_width - 1) | |
9317 | { | |
5f4f0e22 CH |
9318 | op0 = simplify_and_const_int (NULL_RTX, mode, XEXP (op0, 0), |
9319 | (HOST_WIDE_INT) 1); | |
dfbe1b2f RK |
9320 | continue; |
9321 | } | |
230d793d RS |
9322 | break; |
9323 | ||
9324 | case ASHIFTRT: | |
d0ab8cd3 RK |
9325 | /* If this is an equality comparison with zero, we can do this |
9326 | as a logical shift, which might be much simpler. */ | |
9327 | if (equality_comparison_p && const_op == 0 | |
9328 | && GET_CODE (XEXP (op0, 1)) == CONST_INT) | |
9329 | { | |
9330 | op0 = simplify_shift_const (NULL_RTX, LSHIFTRT, mode, | |
9331 | XEXP (op0, 0), | |
9332 | INTVAL (XEXP (op0, 1))); | |
9333 | continue; | |
9334 | } | |
9335 | ||
230d793d RS |
9336 | /* If OP0 is a sign extension and CODE is not an unsigned comparison, |
9337 | do the comparison in a narrower mode. */ | |
9338 | if (! unsigned_comparison_p | |
9339 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9340 | && GET_CODE (XEXP (op0, 0)) == ASHIFT | |
9341 | && XEXP (op0, 1) == XEXP (XEXP (op0, 0), 1) | |
9342 | && (tmode = mode_for_size (mode_width - INTVAL (XEXP (op0, 1)), | |
22331794 | 9343 | MODE_INT, 1)) != BLKmode |
5f4f0e22 CH |
9344 | && ((unsigned HOST_WIDE_INT) const_op <= GET_MODE_MASK (tmode) |
9345 | || ((unsigned HOST_WIDE_INT) - const_op | |
9346 | <= GET_MODE_MASK (tmode)))) | |
230d793d RS |
9347 | { |
9348 | op0 = gen_lowpart_for_combine (tmode, XEXP (XEXP (op0, 0), 0)); | |
9349 | continue; | |
9350 | } | |
9351 | ||
9352 | /* ... fall through ... */ | |
9353 | case LSHIFTRT: | |
9354 | /* If we have (compare (xshiftrt FOO N) (const_int C)) and | |
951553af | 9355 | the low order N bits of FOO are known to be zero, we can do this |
230d793d RS |
9356 | by comparing FOO with C shifted left N bits so long as no |
9357 | overflow occurs. */ | |
9358 | if (GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9359 | && INTVAL (XEXP (op0, 1)) >= 0 | |
5f4f0e22 CH |
9360 | && INTVAL (XEXP (op0, 1)) < HOST_BITS_PER_WIDE_INT |
9361 | && mode_width <= HOST_BITS_PER_WIDE_INT | |
951553af | 9362 | && (nonzero_bits (XEXP (op0, 0), mode) |
5f4f0e22 | 9363 | & (((HOST_WIDE_INT) 1 << INTVAL (XEXP (op0, 1))) - 1)) == 0 |
230d793d RS |
9364 | && (const_op == 0 |
9365 | || (floor_log2 (const_op) + INTVAL (XEXP (op0, 1)) | |
9366 | < mode_width))) | |
9367 | { | |
9368 | const_op <<= INTVAL (XEXP (op0, 1)); | |
5f4f0e22 | 9369 | op1 = GEN_INT (const_op); |
230d793d RS |
9370 | op0 = XEXP (op0, 0); |
9371 | continue; | |
9372 | } | |
9373 | ||
9374 | /* If we are using this shift to extract just the sign bit, we | |
9375 | can replace this with an LT or GE comparison. */ | |
9376 | if (const_op == 0 | |
9377 | && (equality_comparison_p || sign_bit_comparison_p) | |
9378 | && GET_CODE (XEXP (op0, 1)) == CONST_INT | |
9379 | && INTVAL (XEXP (op0, 1)) == mode_width - 1) | |
9380 | { | |
9381 | op0 = XEXP (op0, 0); | |
9382 | code = (code == NE || code == GT ? LT : GE); | |
9383 | continue; | |
9384 | } | |
9385 | break; | |
9386 | } | |
9387 | ||
9388 | break; | |
9389 | } | |
9390 | ||
9391 | /* Now make any compound operations involved in this comparison. Then, | |
9392 | check for an outmost SUBREG on OP0 that isn't doing anything or is | |
9393 | paradoxical. The latter case can only occur when it is known that the | |
9394 | "extra" bits will be zero. Therefore, it is safe to remove the SUBREG. | |
9395 | We can never remove a SUBREG for a non-equality comparison because the | |
9396 | sign bit is in a different place in the underlying object. */ | |
9397 | ||
9398 | op0 = make_compound_operation (op0, op1 == const0_rtx ? COMPARE : SET); | |
9399 | op1 = make_compound_operation (op1, SET); | |
9400 | ||
9401 | if (GET_CODE (op0) == SUBREG && subreg_lowpart_p (op0) | |
9402 | && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT | |
9403 | && (code == NE || code == EQ) | |
9404 | && ((GET_MODE_SIZE (GET_MODE (op0)) | |
9405 | > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))) | |
9406 | { | |
9407 | op0 = SUBREG_REG (op0); | |
9408 | op1 = gen_lowpart_for_combine (GET_MODE (op0), op1); | |
9409 | } | |
9410 | ||
9411 | else if (GET_CODE (op0) == SUBREG && subreg_lowpart_p (op0) | |
9412 | && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT | |
9413 | && (code == NE || code == EQ) | |
ac49a949 RS |
9414 | && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0))) |
9415 | <= HOST_BITS_PER_WIDE_INT) | |
951553af | 9416 | && (nonzero_bits (SUBREG_REG (op0), GET_MODE (SUBREG_REG (op0))) |
230d793d RS |
9417 | & ~ GET_MODE_MASK (GET_MODE (op0))) == 0 |
9418 | && (tem = gen_lowpart_for_combine (GET_MODE (SUBREG_REG (op0)), | |
9419 | op1), | |
951553af | 9420 | (nonzero_bits (tem, GET_MODE (SUBREG_REG (op0))) |
230d793d RS |
9421 | & ~ GET_MODE_MASK (GET_MODE (op0))) == 0)) |
9422 | op0 = SUBREG_REG (op0), op1 = tem; | |
9423 | ||
9424 | /* We now do the opposite procedure: Some machines don't have compare | |
9425 | insns in all modes. If OP0's mode is an integer mode smaller than a | |
9426 | word and we can't do a compare in that mode, see if there is a larger | |
a687e897 RK |
9427 | mode for which we can do the compare. There are a number of cases in |
9428 | which we can use the wider mode. */ | |
230d793d RS |
9429 | |
9430 | mode = GET_MODE (op0); | |
9431 | if (mode != VOIDmode && GET_MODE_CLASS (mode) == MODE_INT | |
9432 | && GET_MODE_SIZE (mode) < UNITS_PER_WORD | |
9433 | && cmp_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing) | |
9434 | for (tmode = GET_MODE_WIDER_MODE (mode); | |
5f4f0e22 CH |
9435 | (tmode != VOIDmode |
9436 | && GET_MODE_BITSIZE (tmode) <= HOST_BITS_PER_WIDE_INT); | |
230d793d | 9437 | tmode = GET_MODE_WIDER_MODE (tmode)) |
a687e897 | 9438 | if (cmp_optab->handlers[(int) tmode].insn_code != CODE_FOR_nothing) |
230d793d | 9439 | { |
951553af | 9440 | /* If the only nonzero bits in OP0 and OP1 are those in the |
a687e897 RK |
9441 | narrower mode and this is an equality or unsigned comparison, |
9442 | we can use the wider mode. Similarly for sign-extended | |
7e4dc511 | 9443 | values, in which case it is true for all comparisons. */ |
a687e897 RK |
9444 | if (((code == EQ || code == NE |
9445 | || code == GEU || code == GTU || code == LEU || code == LTU) | |
951553af RK |
9446 | && (nonzero_bits (op0, tmode) & ~ GET_MODE_MASK (mode)) == 0 |
9447 | && (nonzero_bits (op1, tmode) & ~ GET_MODE_MASK (mode)) == 0) | |
7e4dc511 RK |
9448 | || ((num_sign_bit_copies (op0, tmode) |
9449 | > GET_MODE_BITSIZE (tmode) - GET_MODE_BITSIZE (mode)) | |
a687e897 | 9450 | && (num_sign_bit_copies (op1, tmode) |
58744483 | 9451 | > GET_MODE_BITSIZE (tmode) - GET_MODE_BITSIZE (mode)))) |
a687e897 RK |
9452 | { |
9453 | op0 = gen_lowpart_for_combine (tmode, op0); | |
9454 | op1 = gen_lowpart_for_combine (tmode, op1); | |
9455 | break; | |
9456 | } | |
230d793d | 9457 | |
a687e897 RK |
9458 | /* If this is a test for negative, we can make an explicit |
9459 | test of the sign bit. */ | |
9460 | ||
9461 | if (op1 == const0_rtx && (code == LT || code == GE) | |
9462 | && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) | |
230d793d | 9463 | { |
a687e897 RK |
9464 | op0 = gen_binary (AND, tmode, |
9465 | gen_lowpart_for_combine (tmode, op0), | |
5f4f0e22 CH |
9466 | GEN_INT ((HOST_WIDE_INT) 1 |
9467 | << (GET_MODE_BITSIZE (mode) - 1))); | |
230d793d | 9468 | code = (code == LT) ? NE : EQ; |
a687e897 | 9469 | break; |
230d793d | 9470 | } |
230d793d RS |
9471 | } |
9472 | ||
b7a775b2 RK |
9473 | #ifdef CANONICALIZE_COMPARISON |
9474 | /* If this machine only supports a subset of valid comparisons, see if we | |
9475 | can convert an unsupported one into a supported one. */ | |
9476 | CANONICALIZE_COMPARISON (code, op0, op1); | |
9477 | #endif | |
9478 | ||
230d793d RS |
9479 | *pop0 = op0; |
9480 | *pop1 = op1; | |
9481 | ||
9482 | return code; | |
9483 | } | |
9484 | \f | |
9485 | /* Return 1 if we know that X, a comparison operation, is not operating | |
9486 | on a floating-point value or is EQ or NE, meaning that we can safely | |
9487 | reverse it. */ | |
9488 | ||
9489 | static int | |
9490 | reversible_comparison_p (x) | |
9491 | rtx x; | |
9492 | { | |
9493 | if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT | |
7e2a0d8e | 9494 | || flag_fast_math |
230d793d RS |
9495 | || GET_CODE (x) == NE || GET_CODE (x) == EQ) |
9496 | return 1; | |
9497 | ||
9498 | switch (GET_MODE_CLASS (GET_MODE (XEXP (x, 0)))) | |
9499 | { | |
9500 | case MODE_INT: | |
3ad2180a RK |
9501 | case MODE_PARTIAL_INT: |
9502 | case MODE_COMPLEX_INT: | |
230d793d RS |
9503 | return 1; |
9504 | ||
9505 | case MODE_CC: | |
9210df58 RK |
9506 | /* If the mode of the condition codes tells us that this is safe, |
9507 | we need look no further. */ | |
9508 | if (REVERSIBLE_CC_MODE (GET_MODE (XEXP (x, 0)))) | |
9509 | return 1; | |
9510 | ||
9511 | /* Otherwise try and find where the condition codes were last set and | |
9512 | use that. */ | |
230d793d RS |
9513 | x = get_last_value (XEXP (x, 0)); |
9514 | return (x && GET_CODE (x) == COMPARE | |
3ad2180a | 9515 | && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0)))); |
230d793d RS |
9516 | } |
9517 | ||
9518 | return 0; | |
9519 | } | |
9520 | \f | |
9521 | /* Utility function for following routine. Called when X is part of a value | |
9522 | being stored into reg_last_set_value. Sets reg_last_set_table_tick | |
9523 | for each register mentioned. Similar to mention_regs in cse.c */ | |
9524 | ||
9525 | static void | |
9526 | update_table_tick (x) | |
9527 | rtx x; | |
9528 | { | |
9529 | register enum rtx_code code = GET_CODE (x); | |
9530 | register char *fmt = GET_RTX_FORMAT (code); | |
9531 | register int i; | |
9532 | ||
9533 | if (code == REG) | |
9534 | { | |
9535 | int regno = REGNO (x); | |
9536 | int endregno = regno + (regno < FIRST_PSEUDO_REGISTER | |
9537 | ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); | |
9538 | ||
9539 | for (i = regno; i < endregno; i++) | |
9540 | reg_last_set_table_tick[i] = label_tick; | |
9541 | ||
9542 | return; | |
9543 | } | |
9544 | ||
9545 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
9546 | /* Note that we can't have an "E" in values stored; see | |
9547 | get_last_value_validate. */ | |
9548 | if (fmt[i] == 'e') | |
9549 | update_table_tick (XEXP (x, i)); | |
9550 | } | |
9551 | ||
9552 | /* Record that REG is set to VALUE in insn INSN. If VALUE is zero, we | |
9553 | are saying that the register is clobbered and we no longer know its | |
7988fd36 RK |
9554 | value. If INSN is zero, don't update reg_last_set; this is only permitted |
9555 | with VALUE also zero and is used to invalidate the register. */ | |
230d793d RS |
9556 | |
9557 | static void | |
9558 | record_value_for_reg (reg, insn, value) | |
9559 | rtx reg; | |
9560 | rtx insn; | |
9561 | rtx value; | |
9562 | { | |
9563 | int regno = REGNO (reg); | |
9564 | int endregno = regno + (regno < FIRST_PSEUDO_REGISTER | |
9565 | ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1); | |
9566 | int i; | |
9567 | ||
9568 | /* If VALUE contains REG and we have a previous value for REG, substitute | |
9569 | the previous value. */ | |
9570 | if (value && insn && reg_overlap_mentioned_p (reg, value)) | |
9571 | { | |
9572 | rtx tem; | |
9573 | ||
9574 | /* Set things up so get_last_value is allowed to see anything set up to | |
9575 | our insn. */ | |
9576 | subst_low_cuid = INSN_CUID (insn); | |
9577 | tem = get_last_value (reg); | |
9578 | ||
9579 | if (tem) | |
9580 | value = replace_rtx (copy_rtx (value), reg, tem); | |
9581 | } | |
9582 | ||
9583 | /* For each register modified, show we don't know its value, that | |
ef026f91 RS |
9584 | we don't know about its bitwise content, that its value has been |
9585 | updated, and that we don't know the location of the death of the | |
9586 | register. */ | |
230d793d RS |
9587 | for (i = regno; i < endregno; i ++) |
9588 | { | |
9589 | if (insn) | |
9590 | reg_last_set[i] = insn; | |
9591 | reg_last_set_value[i] = 0; | |
ef026f91 RS |
9592 | reg_last_set_mode[i] = 0; |
9593 | reg_last_set_nonzero_bits[i] = 0; | |
9594 | reg_last_set_sign_bit_copies[i] = 0; | |
230d793d RS |
9595 | reg_last_death[i] = 0; |
9596 | } | |
9597 | ||
9598 | /* Mark registers that are being referenced in this value. */ | |
9599 | if (value) | |
9600 | update_table_tick (value); | |
9601 | ||
9602 | /* Now update the status of each register being set. | |
9603 | If someone is using this register in this block, set this register | |
9604 | to invalid since we will get confused between the two lives in this | |
9605 | basic block. This makes using this register always invalid. In cse, we | |
9606 | scan the table to invalidate all entries using this register, but this | |
9607 | is too much work for us. */ | |
9608 | ||
9609 | for (i = regno; i < endregno; i++) | |
9610 | { | |
9611 | reg_last_set_label[i] = label_tick; | |
9612 | if (value && reg_last_set_table_tick[i] == label_tick) | |
9613 | reg_last_set_invalid[i] = 1; | |
9614 | else | |
9615 | reg_last_set_invalid[i] = 0; | |
9616 | } | |
9617 | ||
9618 | /* The value being assigned might refer to X (like in "x++;"). In that | |
9619 | case, we must replace it with (clobber (const_int 0)) to prevent | |
9620 | infinite loops. */ | |
9621 | if (value && ! get_last_value_validate (&value, | |
9622 | reg_last_set_label[regno], 0)) | |
9623 | { | |
9624 | value = copy_rtx (value); | |
9625 | if (! get_last_value_validate (&value, reg_last_set_label[regno], 1)) | |
9626 | value = 0; | |
9627 | } | |
9628 | ||
55310dad RK |
9629 | /* For the main register being modified, update the value, the mode, the |
9630 | nonzero bits, and the number of sign bit copies. */ | |
9631 | ||
230d793d RS |
9632 | reg_last_set_value[regno] = value; |
9633 | ||
55310dad RK |
9634 | if (value) |
9635 | { | |
2afabb48 | 9636 | subst_low_cuid = INSN_CUID (insn); |
55310dad RK |
9637 | reg_last_set_mode[regno] = GET_MODE (reg); |
9638 | reg_last_set_nonzero_bits[regno] = nonzero_bits (value, GET_MODE (reg)); | |
9639 | reg_last_set_sign_bit_copies[regno] | |
9640 | = num_sign_bit_copies (value, GET_MODE (reg)); | |
9641 | } | |
230d793d RS |
9642 | } |
9643 | ||
9644 | /* Used for communication between the following two routines. */ | |
9645 | static rtx record_dead_insn; | |
9646 | ||
9647 | /* Called via note_stores from record_dead_and_set_regs to handle one | |
9648 | SET or CLOBBER in an insn. */ | |
9649 | ||
9650 | static void | |
9651 | record_dead_and_set_regs_1 (dest, setter) | |
9652 | rtx dest, setter; | |
9653 | { | |
9654 | if (GET_CODE (dest) == REG) | |
9655 | { | |
9656 | /* If we are setting the whole register, we know its value. Otherwise | |
9657 | show that we don't know the value. We can handle SUBREG in | |
9658 | some cases. */ | |
9659 | if (GET_CODE (setter) == SET && dest == SET_DEST (setter)) | |
9660 | record_value_for_reg (dest, record_dead_insn, SET_SRC (setter)); | |
9661 | else if (GET_CODE (setter) == SET | |
9662 | && GET_CODE (SET_DEST (setter)) == SUBREG | |
9663 | && SUBREG_REG (SET_DEST (setter)) == dest | |
90bf8081 | 9664 | && GET_MODE_BITSIZE (GET_MODE (dest)) <= BITS_PER_WORD |
230d793d | 9665 | && subreg_lowpart_p (SET_DEST (setter))) |
d0ab8cd3 RK |
9666 | record_value_for_reg (dest, record_dead_insn, |
9667 | gen_lowpart_for_combine (GET_MODE (dest), | |
9668 | SET_SRC (setter))); | |
230d793d | 9669 | else |
5f4f0e22 | 9670 | record_value_for_reg (dest, record_dead_insn, NULL_RTX); |
230d793d RS |
9671 | } |
9672 | else if (GET_CODE (dest) == MEM | |
9673 | /* Ignore pushes, they clobber nothing. */ | |
9674 | && ! push_operand (dest, GET_MODE (dest))) | |
9675 | mem_last_set = INSN_CUID (record_dead_insn); | |
9676 | } | |
9677 | ||
9678 | /* Update the records of when each REG was most recently set or killed | |
9679 | for the things done by INSN. This is the last thing done in processing | |
9680 | INSN in the combiner loop. | |
9681 | ||
ef026f91 RS |
9682 | We update reg_last_set, reg_last_set_value, reg_last_set_mode, |
9683 | reg_last_set_nonzero_bits, reg_last_set_sign_bit_copies, reg_last_death, | |
9684 | and also the similar information mem_last_set (which insn most recently | |
9685 | modified memory) and last_call_cuid (which insn was the most recent | |
9686 | subroutine call). */ | |
230d793d RS |
9687 | |
9688 | static void | |
9689 | record_dead_and_set_regs (insn) | |
9690 | rtx insn; | |
9691 | { | |
9692 | register rtx link; | |
55310dad RK |
9693 | int i; |
9694 | ||
230d793d RS |
9695 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
9696 | { | |
dbc131f3 RK |
9697 | if (REG_NOTE_KIND (link) == REG_DEAD |
9698 | && GET_CODE (XEXP (link, 0)) == REG) | |
9699 | { | |
9700 | int regno = REGNO (XEXP (link, 0)); | |
9701 | int endregno | |
9702 | = regno + (regno < FIRST_PSEUDO_REGISTER | |
9703 | ? HARD_REGNO_NREGS (regno, GET_MODE (XEXP (link, 0))) | |
9704 | : 1); | |
dbc131f3 RK |
9705 | |
9706 | for (i = regno; i < endregno; i++) | |
9707 | reg_last_death[i] = insn; | |
9708 | } | |
230d793d | 9709 | else if (REG_NOTE_KIND (link) == REG_INC) |
5f4f0e22 | 9710 | record_value_for_reg (XEXP (link, 0), insn, NULL_RTX); |
230d793d RS |
9711 | } |
9712 | ||
9713 | if (GET_CODE (insn) == CALL_INSN) | |
55310dad RK |
9714 | { |
9715 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
9716 | if (call_used_regs[i]) | |
9717 | { | |
9718 | reg_last_set_value[i] = 0; | |
ef026f91 RS |
9719 | reg_last_set_mode[i] = 0; |
9720 | reg_last_set_nonzero_bits[i] = 0; | |
9721 | reg_last_set_sign_bit_copies[i] = 0; | |
55310dad RK |
9722 | reg_last_death[i] = 0; |
9723 | } | |
9724 | ||
9725 | last_call_cuid = mem_last_set = INSN_CUID (insn); | |
9726 | } | |
230d793d RS |
9727 | |
9728 | record_dead_insn = insn; | |
9729 | note_stores (PATTERN (insn), record_dead_and_set_regs_1); | |
9730 | } | |
9731 | \f | |
9732 | /* Utility routine for the following function. Verify that all the registers | |
9733 | mentioned in *LOC are valid when *LOC was part of a value set when | |
9734 | label_tick == TICK. Return 0 if some are not. | |
9735 | ||
9736 | If REPLACE is non-zero, replace the invalid reference with | |
9737 | (clobber (const_int 0)) and return 1. This replacement is useful because | |
9738 | we often can get useful information about the form of a value (e.g., if | |
9739 | it was produced by a shift that always produces -1 or 0) even though | |
9740 | we don't know exactly what registers it was produced from. */ | |
9741 | ||
9742 | static int | |
9743 | get_last_value_validate (loc, tick, replace) | |
9744 | rtx *loc; | |
9745 | int tick; | |
9746 | int replace; | |
9747 | { | |
9748 | rtx x = *loc; | |
9749 | char *fmt = GET_RTX_FORMAT (GET_CODE (x)); | |
9750 | int len = GET_RTX_LENGTH (GET_CODE (x)); | |
9751 | int i; | |
9752 | ||
9753 | if (GET_CODE (x) == REG) | |
9754 | { | |
9755 | int regno = REGNO (x); | |
9756 | int endregno = regno + (regno < FIRST_PSEUDO_REGISTER | |
9757 | ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); | |
9758 | int j; | |
9759 | ||
9760 | for (j = regno; j < endregno; j++) | |
9761 | if (reg_last_set_invalid[j] | |
9762 | /* If this is a pseudo-register that was only set once, it is | |
9763 | always valid. */ | |
9764 | || (! (regno >= FIRST_PSEUDO_REGISTER && reg_n_sets[regno] == 1) | |
9765 | && reg_last_set_label[j] > tick)) | |
9766 | { | |
9767 | if (replace) | |
9768 | *loc = gen_rtx (CLOBBER, GET_MODE (x), const0_rtx); | |
9769 | return replace; | |
9770 | } | |
9771 | ||
9772 | return 1; | |
9773 | } | |
9774 | ||
9775 | for (i = 0; i < len; i++) | |
9776 | if ((fmt[i] == 'e' | |
9777 | && get_last_value_validate (&XEXP (x, i), tick, replace) == 0) | |
9778 | /* Don't bother with these. They shouldn't occur anyway. */ | |
9779 | || fmt[i] == 'E') | |
9780 | return 0; | |
9781 | ||
9782 | /* If we haven't found a reason for it to be invalid, it is valid. */ | |
9783 | return 1; | |
9784 | } | |
9785 | ||
9786 | /* Get the last value assigned to X, if known. Some registers | |
9787 | in the value may be replaced with (clobber (const_int 0)) if their value | |
9788 | is known longer known reliably. */ | |
9789 | ||
9790 | static rtx | |
9791 | get_last_value (x) | |
9792 | rtx x; | |
9793 | { | |
9794 | int regno; | |
9795 | rtx value; | |
9796 | ||
9797 | /* If this is a non-paradoxical SUBREG, get the value of its operand and | |
9798 | then convert it to the desired mode. If this is a paradoxical SUBREG, | |
9799 | we cannot predict what values the "extra" bits might have. */ | |
9800 | if (GET_CODE (x) == SUBREG | |
9801 | && subreg_lowpart_p (x) | |
9802 | && (GET_MODE_SIZE (GET_MODE (x)) | |
9803 | <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) | |
9804 | && (value = get_last_value (SUBREG_REG (x))) != 0) | |
9805 | return gen_lowpart_for_combine (GET_MODE (x), value); | |
9806 | ||
9807 | if (GET_CODE (x) != REG) | |
9808 | return 0; | |
9809 | ||
9810 | regno = REGNO (x); | |
9811 | value = reg_last_set_value[regno]; | |
9812 | ||
d0ab8cd3 | 9813 | /* If we don't have a value or if it isn't for this basic block, return 0. */ |
230d793d RS |
9814 | |
9815 | if (value == 0 | |
9816 | || (reg_n_sets[regno] != 1 | |
55310dad | 9817 | && reg_last_set_label[regno] != label_tick)) |
230d793d RS |
9818 | return 0; |
9819 | ||
d0ab8cd3 | 9820 | /* If the value was set in a later insn that the ones we are processing, |
4090a6b3 RK |
9821 | we can't use it even if the register was only set once, but make a quick |
9822 | check to see if the previous insn set it to something. This is commonly | |
9823 | the case when the same pseudo is used by repeated insns. */ | |
d0ab8cd3 | 9824 | |
4090a6b3 | 9825 | if (INSN_CUID (reg_last_set[regno]) >= subst_low_cuid) |
d0ab8cd3 RK |
9826 | { |
9827 | rtx insn, set; | |
9828 | ||
3adde2a5 RK |
9829 | for (insn = prev_nonnote_insn (subst_insn); |
9830 | insn && INSN_CUID (insn) >= subst_low_cuid; | |
9831 | insn = prev_nonnote_insn (insn)) | |
9832 | ; | |
d0ab8cd3 RK |
9833 | |
9834 | if (insn | |
9835 | && (set = single_set (insn)) != 0 | |
9836 | && rtx_equal_p (SET_DEST (set), x)) | |
9837 | { | |
9838 | value = SET_SRC (set); | |
9839 | ||
9840 | /* Make sure that VALUE doesn't reference X. Replace any | |
9841 | expliit references with a CLOBBER. If there are any remaining | |
9842 | references (rare), don't use the value. */ | |
9843 | ||
9844 | if (reg_mentioned_p (x, value)) | |
9845 | value = replace_rtx (copy_rtx (value), x, | |
9846 | gen_rtx (CLOBBER, GET_MODE (x), const0_rtx)); | |
9847 | ||
9848 | if (reg_overlap_mentioned_p (x, value)) | |
9849 | return 0; | |
9850 | } | |
9851 | else | |
9852 | return 0; | |
9853 | } | |
9854 | ||
9855 | /* If the value has all its registers valid, return it. */ | |
230d793d RS |
9856 | if (get_last_value_validate (&value, reg_last_set_label[regno], 0)) |
9857 | return value; | |
9858 | ||
9859 | /* Otherwise, make a copy and replace any invalid register with | |
9860 | (clobber (const_int 0)). If that fails for some reason, return 0. */ | |
9861 | ||
9862 | value = copy_rtx (value); | |
9863 | if (get_last_value_validate (&value, reg_last_set_label[regno], 1)) | |
9864 | return value; | |
9865 | ||
9866 | return 0; | |
9867 | } | |
9868 | \f | |
9869 | /* Return nonzero if expression X refers to a REG or to memory | |
9870 | that is set in an instruction more recent than FROM_CUID. */ | |
9871 | ||
9872 | static int | |
9873 | use_crosses_set_p (x, from_cuid) | |
9874 | register rtx x; | |
9875 | int from_cuid; | |
9876 | { | |
9877 | register char *fmt; | |
9878 | register int i; | |
9879 | register enum rtx_code code = GET_CODE (x); | |
9880 | ||
9881 | if (code == REG) | |
9882 | { | |
9883 | register int regno = REGNO (x); | |
e28f5732 RK |
9884 | int endreg = regno + (regno < FIRST_PSEUDO_REGISTER |
9885 | ? HARD_REGNO_NREGS (regno, GET_MODE (x)) : 1); | |
9886 | ||
230d793d RS |
9887 | #ifdef PUSH_ROUNDING |
9888 | /* Don't allow uses of the stack pointer to be moved, | |
9889 | because we don't know whether the move crosses a push insn. */ | |
9890 | if (regno == STACK_POINTER_REGNUM) | |
9891 | return 1; | |
9892 | #endif | |
e28f5732 RK |
9893 | for (;regno < endreg; regno++) |
9894 | if (reg_last_set[regno] | |
9895 | && INSN_CUID (reg_last_set[regno]) > from_cuid) | |
9896 | return 1; | |
9897 | return 0; | |
230d793d RS |
9898 | } |
9899 | ||
9900 | if (code == MEM && mem_last_set > from_cuid) | |
9901 | return 1; | |
9902 | ||
9903 | fmt = GET_RTX_FORMAT (code); | |
9904 | ||
9905 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
9906 | { | |
9907 | if (fmt[i] == 'E') | |
9908 | { | |
9909 | register int j; | |
9910 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
9911 | if (use_crosses_set_p (XVECEXP (x, i, j), from_cuid)) | |
9912 | return 1; | |
9913 | } | |
9914 | else if (fmt[i] == 'e' | |
9915 | && use_crosses_set_p (XEXP (x, i), from_cuid)) | |
9916 | return 1; | |
9917 | } | |
9918 | return 0; | |
9919 | } | |
9920 | \f | |
9921 | /* Define three variables used for communication between the following | |
9922 | routines. */ | |
9923 | ||
9924 | static int reg_dead_regno, reg_dead_endregno; | |
9925 | static int reg_dead_flag; | |
9926 | ||
9927 | /* Function called via note_stores from reg_dead_at_p. | |
9928 | ||
9929 | If DEST is within [reg_dead_rengno, reg_dead_endregno), set | |
9930 | reg_dead_flag to 1 if X is a CLOBBER and to -1 it is a SET. */ | |
9931 | ||
9932 | static void | |
9933 | reg_dead_at_p_1 (dest, x) | |
9934 | rtx dest; | |
9935 | rtx x; | |
9936 | { | |
9937 | int regno, endregno; | |
9938 | ||
9939 | if (GET_CODE (dest) != REG) | |
9940 | return; | |
9941 | ||
9942 | regno = REGNO (dest); | |
9943 | endregno = regno + (regno < FIRST_PSEUDO_REGISTER | |
9944 | ? HARD_REGNO_NREGS (regno, GET_MODE (dest)) : 1); | |
9945 | ||
9946 | if (reg_dead_endregno > regno && reg_dead_regno < endregno) | |
9947 | reg_dead_flag = (GET_CODE (x) == CLOBBER) ? 1 : -1; | |
9948 | } | |
9949 | ||
9950 | /* Return non-zero if REG is known to be dead at INSN. | |
9951 | ||
9952 | We scan backwards from INSN. If we hit a REG_DEAD note or a CLOBBER | |
9953 | referencing REG, it is dead. If we hit a SET referencing REG, it is | |
9954 | live. Otherwise, see if it is live or dead at the start of the basic | |
6e25d159 RK |
9955 | block we are in. Hard regs marked as being live in NEWPAT_USED_REGS |
9956 | must be assumed to be always live. */ | |
230d793d RS |
9957 | |
9958 | static int | |
9959 | reg_dead_at_p (reg, insn) | |
9960 | rtx reg; | |
9961 | rtx insn; | |
9962 | { | |
9963 | int block, i; | |
9964 | ||
9965 | /* Set variables for reg_dead_at_p_1. */ | |
9966 | reg_dead_regno = REGNO (reg); | |
9967 | reg_dead_endregno = reg_dead_regno + (reg_dead_regno < FIRST_PSEUDO_REGISTER | |
9968 | ? HARD_REGNO_NREGS (reg_dead_regno, | |
9969 | GET_MODE (reg)) | |
9970 | : 1); | |
9971 | ||
9972 | reg_dead_flag = 0; | |
9973 | ||
6e25d159 RK |
9974 | /* Check that reg isn't mentioned in NEWPAT_USED_REGS. */ |
9975 | if (reg_dead_regno < FIRST_PSEUDO_REGISTER) | |
9976 | { | |
9977 | for (i = reg_dead_regno; i < reg_dead_endregno; i++) | |
9978 | if (TEST_HARD_REG_BIT (newpat_used_regs, i)) | |
9979 | return 0; | |
9980 | } | |
9981 | ||
230d793d RS |
9982 | /* Scan backwards until we find a REG_DEAD note, SET, CLOBBER, label, or |
9983 | beginning of function. */ | |
9984 | for (; insn && GET_CODE (insn) != CODE_LABEL; | |
9985 | insn = prev_nonnote_insn (insn)) | |
9986 | { | |
9987 | note_stores (PATTERN (insn), reg_dead_at_p_1); | |
9988 | if (reg_dead_flag) | |
9989 | return reg_dead_flag == 1 ? 1 : 0; | |
9990 | ||
9991 | if (find_regno_note (insn, REG_DEAD, reg_dead_regno)) | |
9992 | return 1; | |
9993 | } | |
9994 | ||
9995 | /* Get the basic block number that we were in. */ | |
9996 | if (insn == 0) | |
9997 | block = 0; | |
9998 | else | |
9999 | { | |
10000 | for (block = 0; block < n_basic_blocks; block++) | |
10001 | if (insn == basic_block_head[block]) | |
10002 | break; | |
10003 | ||
10004 | if (block == n_basic_blocks) | |
10005 | return 0; | |
10006 | } | |
10007 | ||
10008 | for (i = reg_dead_regno; i < reg_dead_endregno; i++) | |
5f4f0e22 CH |
10009 | if (basic_block_live_at_start[block][i / REGSET_ELT_BITS] |
10010 | & ((REGSET_ELT_TYPE) 1 << (i % REGSET_ELT_BITS))) | |
230d793d RS |
10011 | return 0; |
10012 | ||
10013 | return 1; | |
10014 | } | |
6e25d159 RK |
10015 | \f |
10016 | /* Note hard registers in X that are used. This code is similar to | |
10017 | that in flow.c, but much simpler since we don't care about pseudos. */ | |
10018 | ||
10019 | static void | |
10020 | mark_used_regs_combine (x) | |
10021 | rtx x; | |
10022 | { | |
10023 | register RTX_CODE code = GET_CODE (x); | |
10024 | register int regno; | |
10025 | int i; | |
10026 | ||
10027 | switch (code) | |
10028 | { | |
10029 | case LABEL_REF: | |
10030 | case SYMBOL_REF: | |
10031 | case CONST_INT: | |
10032 | case CONST: | |
10033 | case CONST_DOUBLE: | |
10034 | case PC: | |
10035 | case ADDR_VEC: | |
10036 | case ADDR_DIFF_VEC: | |
10037 | case ASM_INPUT: | |
10038 | #ifdef HAVE_cc0 | |
10039 | /* CC0 must die in the insn after it is set, so we don't need to take | |
10040 | special note of it here. */ | |
10041 | case CC0: | |
10042 | #endif | |
10043 | return; | |
10044 | ||
10045 | case CLOBBER: | |
10046 | /* If we are clobbering a MEM, mark any hard registers inside the | |
10047 | address as used. */ | |
10048 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
10049 | mark_used_regs_combine (XEXP (XEXP (x, 0), 0)); | |
10050 | return; | |
10051 | ||
10052 | case REG: | |
10053 | regno = REGNO (x); | |
10054 | /* A hard reg in a wide mode may really be multiple registers. | |
10055 | If so, mark all of them just like the first. */ | |
10056 | if (regno < FIRST_PSEUDO_REGISTER) | |
10057 | { | |
10058 | /* None of this applies to the stack, frame or arg pointers */ | |
10059 | if (regno == STACK_POINTER_REGNUM | |
10060 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM | |
10061 | || regno == HARD_FRAME_POINTER_REGNUM | |
10062 | #endif | |
10063 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM | |
10064 | || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
10065 | #endif | |
10066 | || regno == FRAME_POINTER_REGNUM) | |
10067 | return; | |
10068 | ||
10069 | i = HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
10070 | while (i-- > 0) | |
10071 | SET_HARD_REG_BIT (newpat_used_regs, regno + i); | |
10072 | } | |
10073 | return; | |
10074 | ||
10075 | case SET: | |
10076 | { | |
10077 | /* If setting a MEM, or a SUBREG of a MEM, then note any hard regs in | |
10078 | the address. */ | |
10079 | register rtx testreg = SET_DEST (x); | |
10080 | ||
e048778f RK |
10081 | while (GET_CODE (testreg) == SUBREG |
10082 | || GET_CODE (testreg) == ZERO_EXTRACT | |
10083 | || GET_CODE (testreg) == SIGN_EXTRACT | |
10084 | || GET_CODE (testreg) == STRICT_LOW_PART) | |
6e25d159 RK |
10085 | testreg = XEXP (testreg, 0); |
10086 | ||
10087 | if (GET_CODE (testreg) == MEM) | |
10088 | mark_used_regs_combine (XEXP (testreg, 0)); | |
10089 | ||
10090 | mark_used_regs_combine (SET_SRC (x)); | |
10091 | return; | |
10092 | } | |
10093 | } | |
10094 | ||
10095 | /* Recursively scan the operands of this expression. */ | |
10096 | ||
10097 | { | |
10098 | register char *fmt = GET_RTX_FORMAT (code); | |
10099 | ||
10100 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
10101 | { | |
10102 | if (fmt[i] == 'e') | |
10103 | mark_used_regs_combine (XEXP (x, i)); | |
10104 | else if (fmt[i] == 'E') | |
10105 | { | |
10106 | register int j; | |
10107 | ||
10108 | for (j = 0; j < XVECLEN (x, i); j++) | |
10109 | mark_used_regs_combine (XVECEXP (x, i, j)); | |
10110 | } | |
10111 | } | |
10112 | } | |
10113 | } | |
10114 | ||
230d793d RS |
10115 | \f |
10116 | /* Remove register number REGNO from the dead registers list of INSN. | |
10117 | ||
10118 | Return the note used to record the death, if there was one. */ | |
10119 | ||
10120 | rtx | |
10121 | remove_death (regno, insn) | |
10122 | int regno; | |
10123 | rtx insn; | |
10124 | { | |
10125 | register rtx note = find_regno_note (insn, REG_DEAD, regno); | |
10126 | ||
10127 | if (note) | |
1a26b032 RK |
10128 | { |
10129 | reg_n_deaths[regno]--; | |
10130 | remove_note (insn, note); | |
10131 | } | |
230d793d RS |
10132 | |
10133 | return note; | |
10134 | } | |
10135 | ||
10136 | /* For each register (hardware or pseudo) used within expression X, if its | |
10137 | death is in an instruction with cuid between FROM_CUID (inclusive) and | |
10138 | TO_INSN (exclusive), put a REG_DEAD note for that register in the | |
10139 | list headed by PNOTES. | |
10140 | ||
10141 | This is done when X is being merged by combination into TO_INSN. These | |
10142 | notes will then be distributed as needed. */ | |
10143 | ||
10144 | static void | |
10145 | move_deaths (x, from_cuid, to_insn, pnotes) | |
10146 | rtx x; | |
10147 | int from_cuid; | |
10148 | rtx to_insn; | |
10149 | rtx *pnotes; | |
10150 | { | |
10151 | register char *fmt; | |
10152 | register int len, i; | |
10153 | register enum rtx_code code = GET_CODE (x); | |
10154 | ||
10155 | if (code == REG) | |
10156 | { | |
10157 | register int regno = REGNO (x); | |
10158 | register rtx where_dead = reg_last_death[regno]; | |
10159 | ||
10160 | if (where_dead && INSN_CUID (where_dead) >= from_cuid | |
10161 | && INSN_CUID (where_dead) < INSN_CUID (to_insn)) | |
10162 | { | |
dbc131f3 | 10163 | rtx note = remove_death (regno, where_dead); |
230d793d RS |
10164 | |
10165 | /* It is possible for the call above to return 0. This can occur | |
10166 | when reg_last_death points to I2 or I1 that we combined with. | |
dbc131f3 RK |
10167 | In that case make a new note. |
10168 | ||
10169 | We must also check for the case where X is a hard register | |
10170 | and NOTE is a death note for a range of hard registers | |
10171 | including X. In that case, we must put REG_DEAD notes for | |
10172 | the remaining registers in place of NOTE. */ | |
10173 | ||
10174 | if (note != 0 && regno < FIRST_PSEUDO_REGISTER | |
10175 | && (GET_MODE_SIZE (GET_MODE (XEXP (note, 0))) | |
10176 | != GET_MODE_SIZE (GET_MODE (x)))) | |
10177 | { | |
10178 | int deadregno = REGNO (XEXP (note, 0)); | |
10179 | int deadend | |
10180 | = (deadregno + HARD_REGNO_NREGS (deadregno, | |
10181 | GET_MODE (XEXP (note, 0)))); | |
10182 | int ourend = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
10183 | int i; | |
10184 | ||
10185 | for (i = deadregno; i < deadend; i++) | |
10186 | if (i < regno || i >= ourend) | |
10187 | REG_NOTES (where_dead) | |
10188 | = gen_rtx (EXPR_LIST, REG_DEAD, | |
36b878d1 | 10189 | gen_rtx (REG, reg_raw_mode[i], i), |
dbc131f3 RK |
10190 | REG_NOTES (where_dead)); |
10191 | } | |
230d793d | 10192 | |
dbc131f3 | 10193 | if (note != 0 && GET_MODE (XEXP (note, 0)) == GET_MODE (x)) |
230d793d RS |
10194 | { |
10195 | XEXP (note, 1) = *pnotes; | |
10196 | *pnotes = note; | |
10197 | } | |
10198 | else | |
10199 | *pnotes = gen_rtx (EXPR_LIST, REG_DEAD, x, *pnotes); | |
1a26b032 RK |
10200 | |
10201 | reg_n_deaths[regno]++; | |
230d793d RS |
10202 | } |
10203 | ||
10204 | return; | |
10205 | } | |
10206 | ||
10207 | else if (GET_CODE (x) == SET) | |
10208 | { | |
10209 | rtx dest = SET_DEST (x); | |
10210 | ||
10211 | move_deaths (SET_SRC (x), from_cuid, to_insn, pnotes); | |
10212 | ||
a7c99304 RK |
10213 | /* In the case of a ZERO_EXTRACT, a STRICT_LOW_PART, or a SUBREG |
10214 | that accesses one word of a multi-word item, some | |
10215 | piece of everything register in the expression is used by | |
10216 | this insn, so remove any old death. */ | |
10217 | ||
10218 | if (GET_CODE (dest) == ZERO_EXTRACT | |
10219 | || GET_CODE (dest) == STRICT_LOW_PART | |
10220 | || (GET_CODE (dest) == SUBREG | |
10221 | && (((GET_MODE_SIZE (GET_MODE (dest)) | |
10222 | + UNITS_PER_WORD - 1) / UNITS_PER_WORD) | |
10223 | == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) | |
10224 | + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))) | |
230d793d | 10225 | { |
a7c99304 RK |
10226 | move_deaths (dest, from_cuid, to_insn, pnotes); |
10227 | return; | |
230d793d RS |
10228 | } |
10229 | ||
a7c99304 RK |
10230 | /* If this is some other SUBREG, we know it replaces the entire |
10231 | value, so use that as the destination. */ | |
10232 | if (GET_CODE (dest) == SUBREG) | |
10233 | dest = SUBREG_REG (dest); | |
10234 | ||
10235 | /* If this is a MEM, adjust deaths of anything used in the address. | |
10236 | For a REG (the only other possibility), the entire value is | |
10237 | being replaced so the old value is not used in this insn. */ | |
230d793d RS |
10238 | |
10239 | if (GET_CODE (dest) == MEM) | |
10240 | move_deaths (XEXP (dest, 0), from_cuid, to_insn, pnotes); | |
10241 | return; | |
10242 | } | |
10243 | ||
10244 | else if (GET_CODE (x) == CLOBBER) | |
10245 | return; | |
10246 | ||
10247 | len = GET_RTX_LENGTH (code); | |
10248 | fmt = GET_RTX_FORMAT (code); | |
10249 | ||
10250 | for (i = 0; i < len; i++) | |
10251 | { | |
10252 | if (fmt[i] == 'E') | |
10253 | { | |
10254 | register int j; | |
10255 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
10256 | move_deaths (XVECEXP (x, i, j), from_cuid, to_insn, pnotes); | |
10257 | } | |
10258 | else if (fmt[i] == 'e') | |
10259 | move_deaths (XEXP (x, i), from_cuid, to_insn, pnotes); | |
10260 | } | |
10261 | } | |
10262 | \f | |
a7c99304 RK |
10263 | /* Return 1 if X is the target of a bit-field assignment in BODY, the |
10264 | pattern of an insn. X must be a REG. */ | |
230d793d RS |
10265 | |
10266 | static int | |
a7c99304 RK |
10267 | reg_bitfield_target_p (x, body) |
10268 | rtx x; | |
230d793d RS |
10269 | rtx body; |
10270 | { | |
10271 | int i; | |
10272 | ||
10273 | if (GET_CODE (body) == SET) | |
a7c99304 RK |
10274 | { |
10275 | rtx dest = SET_DEST (body); | |
10276 | rtx target; | |
10277 | int regno, tregno, endregno, endtregno; | |
10278 | ||
10279 | if (GET_CODE (dest) == ZERO_EXTRACT) | |
10280 | target = XEXP (dest, 0); | |
10281 | else if (GET_CODE (dest) == STRICT_LOW_PART) | |
10282 | target = SUBREG_REG (XEXP (dest, 0)); | |
10283 | else | |
10284 | return 0; | |
10285 | ||
10286 | if (GET_CODE (target) == SUBREG) | |
10287 | target = SUBREG_REG (target); | |
10288 | ||
10289 | if (GET_CODE (target) != REG) | |
10290 | return 0; | |
10291 | ||
10292 | tregno = REGNO (target), regno = REGNO (x); | |
10293 | if (tregno >= FIRST_PSEUDO_REGISTER || regno >= FIRST_PSEUDO_REGISTER) | |
10294 | return target == x; | |
10295 | ||
10296 | endtregno = tregno + HARD_REGNO_NREGS (tregno, GET_MODE (target)); | |
10297 | endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
10298 | ||
10299 | return endregno > tregno && regno < endtregno; | |
10300 | } | |
230d793d RS |
10301 | |
10302 | else if (GET_CODE (body) == PARALLEL) | |
10303 | for (i = XVECLEN (body, 0) - 1; i >= 0; i--) | |
a7c99304 | 10304 | if (reg_bitfield_target_p (x, XVECEXP (body, 0, i))) |
230d793d RS |
10305 | return 1; |
10306 | ||
10307 | return 0; | |
10308 | } | |
10309 | \f | |
10310 | /* Given a chain of REG_NOTES originally from FROM_INSN, try to place them | |
10311 | as appropriate. I3 and I2 are the insns resulting from the combination | |
10312 | insns including FROM (I2 may be zero). | |
10313 | ||
10314 | ELIM_I2 and ELIM_I1 are either zero or registers that we know will | |
10315 | not need REG_DEAD notes because they are being substituted for. This | |
10316 | saves searching in the most common cases. | |
10317 | ||
10318 | Each note in the list is either ignored or placed on some insns, depending | |
10319 | on the type of note. */ | |
10320 | ||
10321 | static void | |
10322 | distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) | |
10323 | rtx notes; | |
10324 | rtx from_insn; | |
10325 | rtx i3, i2; | |
10326 | rtx elim_i2, elim_i1; | |
10327 | { | |
10328 | rtx note, next_note; | |
10329 | rtx tem; | |
10330 | ||
10331 | for (note = notes; note; note = next_note) | |
10332 | { | |
10333 | rtx place = 0, place2 = 0; | |
10334 | ||
10335 | /* If this NOTE references a pseudo register, ensure it references | |
10336 | the latest copy of that register. */ | |
10337 | if (XEXP (note, 0) && GET_CODE (XEXP (note, 0)) == REG | |
10338 | && REGNO (XEXP (note, 0)) >= FIRST_PSEUDO_REGISTER) | |
10339 | XEXP (note, 0) = regno_reg_rtx[REGNO (XEXP (note, 0))]; | |
10340 | ||
10341 | next_note = XEXP (note, 1); | |
10342 | switch (REG_NOTE_KIND (note)) | |
10343 | { | |
10344 | case REG_UNUSED: | |
176c9e6b JW |
10345 | /* If this note is from any insn other than i3, then we have no |
10346 | use for it, and must ignore it. | |
10347 | ||
10348 | Any clobbers for i3 may still exist, and so we must process | |
10349 | REG_UNUSED notes from that insn. | |
10350 | ||
10351 | Any clobbers from i2 or i1 can only exist if they were added by | |
10352 | recog_for_combine. In that case, recog_for_combine created the | |
10353 | necessary REG_UNUSED notes. Trying to keep any original | |
10354 | REG_UNUSED notes from these insns can cause incorrect output | |
10355 | if it is for the same register as the original i3 dest. | |
10356 | In that case, we will notice that the register is set in i3, | |
10357 | and then add a REG_UNUSED note for the destination of i3, which | |
10358 | is wrong. */ | |
10359 | if (from_insn != i3) | |
10360 | break; | |
10361 | ||
230d793d RS |
10362 | /* If this register is set or clobbered in I3, put the note there |
10363 | unless there is one already. */ | |
176c9e6b | 10364 | else if (reg_set_p (XEXP (note, 0), PATTERN (i3))) |
230d793d RS |
10365 | { |
10366 | if (! (GET_CODE (XEXP (note, 0)) == REG | |
10367 | ? find_regno_note (i3, REG_UNUSED, REGNO (XEXP (note, 0))) | |
10368 | : find_reg_note (i3, REG_UNUSED, XEXP (note, 0)))) | |
10369 | place = i3; | |
10370 | } | |
10371 | /* Otherwise, if this register is used by I3, then this register | |
10372 | now dies here, so we must put a REG_DEAD note here unless there | |
10373 | is one already. */ | |
10374 | else if (reg_referenced_p (XEXP (note, 0), PATTERN (i3)) | |
10375 | && ! (GET_CODE (XEXP (note, 0)) == REG | |
10376 | ? find_regno_note (i3, REG_DEAD, REGNO (XEXP (note, 0))) | |
10377 | : find_reg_note (i3, REG_DEAD, XEXP (note, 0)))) | |
10378 | { | |
10379 | PUT_REG_NOTE_KIND (note, REG_DEAD); | |
10380 | place = i3; | |
10381 | } | |
10382 | break; | |
10383 | ||
10384 | case REG_EQUAL: | |
10385 | case REG_EQUIV: | |
10386 | case REG_NONNEG: | |
10387 | /* These notes say something about results of an insn. We can | |
10388 | only support them if they used to be on I3 in which case they | |
a687e897 RK |
10389 | remain on I3. Otherwise they are ignored. |
10390 | ||
10391 | If the note refers to an expression that is not a constant, we | |
10392 | must also ignore the note since we cannot tell whether the | |
10393 | equivalence is still true. It might be possible to do | |
10394 | slightly better than this (we only have a problem if I2DEST | |
10395 | or I1DEST is present in the expression), but it doesn't | |
10396 | seem worth the trouble. */ | |
10397 | ||
10398 | if (from_insn == i3 | |
10399 | && (XEXP (note, 0) == 0 || CONSTANT_P (XEXP (note, 0)))) | |
230d793d RS |
10400 | place = i3; |
10401 | break; | |
10402 | ||
10403 | case REG_INC: | |
10404 | case REG_NO_CONFLICT: | |
10405 | case REG_LABEL: | |
10406 | /* These notes say something about how a register is used. They must | |
10407 | be present on any use of the register in I2 or I3. */ | |
10408 | if (reg_mentioned_p (XEXP (note, 0), PATTERN (i3))) | |
10409 | place = i3; | |
10410 | ||
10411 | if (i2 && reg_mentioned_p (XEXP (note, 0), PATTERN (i2))) | |
10412 | { | |
10413 | if (place) | |
10414 | place2 = i2; | |
10415 | else | |
10416 | place = i2; | |
10417 | } | |
10418 | break; | |
10419 | ||
10420 | case REG_WAS_0: | |
10421 | /* It is too much trouble to try to see if this note is still | |
10422 | correct in all situations. It is better to simply delete it. */ | |
10423 | break; | |
10424 | ||
10425 | case REG_RETVAL: | |
10426 | /* If the insn previously containing this note still exists, | |
10427 | put it back where it was. Otherwise move it to the previous | |
10428 | insn. Adjust the corresponding REG_LIBCALL note. */ | |
10429 | if (GET_CODE (from_insn) != NOTE) | |
10430 | place = from_insn; | |
10431 | else | |
10432 | { | |
5f4f0e22 | 10433 | tem = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX); |
230d793d RS |
10434 | place = prev_real_insn (from_insn); |
10435 | if (tem && place) | |
10436 | XEXP (tem, 0) = place; | |
10437 | } | |
10438 | break; | |
10439 | ||
10440 | case REG_LIBCALL: | |
10441 | /* This is handled similarly to REG_RETVAL. */ | |
10442 | if (GET_CODE (from_insn) != NOTE) | |
10443 | place = from_insn; | |
10444 | else | |
10445 | { | |
5f4f0e22 | 10446 | tem = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX); |
230d793d RS |
10447 | place = next_real_insn (from_insn); |
10448 | if (tem && place) | |
10449 | XEXP (tem, 0) = place; | |
10450 | } | |
10451 | break; | |
10452 | ||
10453 | case REG_DEAD: | |
10454 | /* If the register is used as an input in I3, it dies there. | |
10455 | Similarly for I2, if it is non-zero and adjacent to I3. | |
10456 | ||
10457 | If the register is not used as an input in either I3 or I2 | |
10458 | and it is not one of the registers we were supposed to eliminate, | |
10459 | there are two possibilities. We might have a non-adjacent I2 | |
10460 | or we might have somehow eliminated an additional register | |
10461 | from a computation. For example, we might have had A & B where | |
10462 | we discover that B will always be zero. In this case we will | |
10463 | eliminate the reference to A. | |
10464 | ||
10465 | In both cases, we must search to see if we can find a previous | |
10466 | use of A and put the death note there. */ | |
10467 | ||
6e2d1486 RK |
10468 | if (from_insn |
10469 | && GET_CODE (from_insn) == CALL_INSN | |
10470 | && find_reg_fusage (from_insn, USE, XEXP (note, 0))) | |
10471 | place = from_insn; | |
10472 | else if (reg_referenced_p (XEXP (note, 0), PATTERN (i3))) | |
230d793d RS |
10473 | place = i3; |
10474 | else if (i2 != 0 && next_nonnote_insn (i2) == i3 | |
10475 | && reg_referenced_p (XEXP (note, 0), PATTERN (i2))) | |
10476 | place = i2; | |
10477 | ||
10478 | if (XEXP (note, 0) == elim_i2 || XEXP (note, 0) == elim_i1) | |
10479 | break; | |
10480 | ||
510dd77e RK |
10481 | /* If the register is used in both I2 and I3 and it dies in I3, |
10482 | we might have added another reference to it. If reg_n_refs | |
10483 | was 2, bump it to 3. This has to be correct since the | |
10484 | register must have been set somewhere. The reason this is | |
10485 | done is because local-alloc.c treats 2 references as a | |
10486 | special case. */ | |
10487 | ||
10488 | if (place == i3 && i2 != 0 && GET_CODE (XEXP (note, 0)) == REG | |
10489 | && reg_n_refs[REGNO (XEXP (note, 0))]== 2 | |
10490 | && reg_referenced_p (XEXP (note, 0), PATTERN (i2))) | |
10491 | reg_n_refs[REGNO (XEXP (note, 0))] = 3; | |
10492 | ||
230d793d RS |
10493 | if (place == 0) |
10494 | for (tem = prev_nonnote_insn (i3); | |
10495 | tem && (GET_CODE (tem) == INSN | |
10496 | || GET_CODE (tem) == CALL_INSN); | |
10497 | tem = prev_nonnote_insn (tem)) | |
10498 | { | |
10499 | /* If the register is being set at TEM, see if that is all | |
10500 | TEM is doing. If so, delete TEM. Otherwise, make this | |
10501 | into a REG_UNUSED note instead. */ | |
10502 | if (reg_set_p (XEXP (note, 0), PATTERN (tem))) | |
10503 | { | |
10504 | rtx set = single_set (tem); | |
10505 | ||
5089e22e RS |
10506 | /* Verify that it was the set, and not a clobber that |
10507 | modified the register. */ | |
10508 | ||
10509 | if (set != 0 && ! side_effects_p (SET_SRC (set)) | |
10510 | && rtx_equal_p (XEXP (note, 0), SET_DEST (set))) | |
230d793d RS |
10511 | { |
10512 | /* Move the notes and links of TEM elsewhere. | |
10513 | This might delete other dead insns recursively. | |
10514 | First set the pattern to something that won't use | |
10515 | any register. */ | |
10516 | ||
10517 | PATTERN (tem) = pc_rtx; | |
10518 | ||
5f4f0e22 CH |
10519 | distribute_notes (REG_NOTES (tem), tem, tem, |
10520 | NULL_RTX, NULL_RTX, NULL_RTX); | |
230d793d RS |
10521 | distribute_links (LOG_LINKS (tem)); |
10522 | ||
10523 | PUT_CODE (tem, NOTE); | |
10524 | NOTE_LINE_NUMBER (tem) = NOTE_INSN_DELETED; | |
10525 | NOTE_SOURCE_FILE (tem) = 0; | |
10526 | } | |
10527 | else | |
10528 | { | |
10529 | PUT_REG_NOTE_KIND (note, REG_UNUSED); | |
10530 | ||
10531 | /* If there isn't already a REG_UNUSED note, put one | |
10532 | here. */ | |
10533 | if (! find_regno_note (tem, REG_UNUSED, | |
10534 | REGNO (XEXP (note, 0)))) | |
10535 | place = tem; | |
10536 | break; | |
10537 | } | |
10538 | } | |
13018fad RE |
10539 | else if (reg_referenced_p (XEXP (note, 0), PATTERN (tem)) |
10540 | || (GET_CODE (tem) == CALL_INSN | |
10541 | && find_reg_fusage (tem, USE, XEXP (note, 0)))) | |
230d793d RS |
10542 | { |
10543 | place = tem; | |
10544 | break; | |
10545 | } | |
10546 | } | |
10547 | ||
10548 | /* If the register is set or already dead at PLACE, we needn't do | |
10549 | anything with this note if it is still a REG_DEAD note. | |
10550 | ||
10551 | Note that we cannot use just `dead_or_set_p' here since we can | |
10552 | convert an assignment to a register into a bit-field assignment. | |
10553 | Therefore, we must also omit the note if the register is the | |
10554 | target of a bitfield assignment. */ | |
10555 | ||
10556 | if (place && REG_NOTE_KIND (note) == REG_DEAD) | |
10557 | { | |
10558 | int regno = REGNO (XEXP (note, 0)); | |
10559 | ||
10560 | if (dead_or_set_p (place, XEXP (note, 0)) | |
10561 | || reg_bitfield_target_p (XEXP (note, 0), PATTERN (place))) | |
10562 | { | |
10563 | /* Unless the register previously died in PLACE, clear | |
10564 | reg_last_death. [I no longer understand why this is | |
10565 | being done.] */ | |
10566 | if (reg_last_death[regno] != place) | |
10567 | reg_last_death[regno] = 0; | |
10568 | place = 0; | |
10569 | } | |
10570 | else | |
10571 | reg_last_death[regno] = place; | |
10572 | ||
10573 | /* If this is a death note for a hard reg that is occupying | |
10574 | multiple registers, ensure that we are still using all | |
10575 | parts of the object. If we find a piece of the object | |
10576 | that is unused, we must add a USE for that piece before | |
10577 | PLACE and put the appropriate REG_DEAD note on it. | |
10578 | ||
10579 | An alternative would be to put a REG_UNUSED for the pieces | |
10580 | on the insn that set the register, but that can't be done if | |
10581 | it is not in the same block. It is simpler, though less | |
10582 | efficient, to add the USE insns. */ | |
10583 | ||
10584 | if (place && regno < FIRST_PSEUDO_REGISTER | |
10585 | && HARD_REGNO_NREGS (regno, GET_MODE (XEXP (note, 0))) > 1) | |
10586 | { | |
10587 | int endregno | |
10588 | = regno + HARD_REGNO_NREGS (regno, | |
10589 | GET_MODE (XEXP (note, 0))); | |
10590 | int all_used = 1; | |
10591 | int i; | |
10592 | ||
10593 | for (i = regno; i < endregno; i++) | |
9fd5bb62 JW |
10594 | if (! refers_to_regno_p (i, i + 1, PATTERN (place), 0) |
10595 | && ! find_regno_fusage (place, USE, i)) | |
230d793d | 10596 | { |
485eeec4 | 10597 | rtx piece = gen_rtx (REG, reg_raw_mode[i], i); |
28f6d3af RK |
10598 | rtx p; |
10599 | ||
10600 | /* See if we already placed a USE note for this | |
10601 | register in front of PLACE. */ | |
10602 | for (p = place; | |
10603 | GET_CODE (PREV_INSN (p)) == INSN | |
10604 | && GET_CODE (PATTERN (PREV_INSN (p))) == USE; | |
10605 | p = PREV_INSN (p)) | |
10606 | if (rtx_equal_p (piece, | |
10607 | XEXP (PATTERN (PREV_INSN (p)), 0))) | |
10608 | { | |
10609 | p = 0; | |
10610 | break; | |
10611 | } | |
10612 | ||
10613 | if (p) | |
10614 | { | |
10615 | rtx use_insn | |
10616 | = emit_insn_before (gen_rtx (USE, VOIDmode, | |
10617 | piece), | |
10618 | p); | |
10619 | REG_NOTES (use_insn) | |
10620 | = gen_rtx (EXPR_LIST, REG_DEAD, piece, | |
10621 | REG_NOTES (use_insn)); | |
10622 | } | |
230d793d | 10623 | |
5089e22e | 10624 | all_used = 0; |
230d793d RS |
10625 | } |
10626 | ||
a394b17b JW |
10627 | /* Check for the case where the register dying partially |
10628 | overlaps the register set by this insn. */ | |
10629 | if (all_used) | |
10630 | for (i = regno; i < endregno; i++) | |
10631 | if (dead_or_set_regno_p (place, i)) | |
10632 | { | |
10633 | all_used = 0; | |
10634 | break; | |
10635 | } | |
10636 | ||
230d793d RS |
10637 | if (! all_used) |
10638 | { | |
10639 | /* Put only REG_DEAD notes for pieces that are | |
10640 | still used and that are not already dead or set. */ | |
10641 | ||
10642 | for (i = regno; i < endregno; i++) | |
10643 | { | |
485eeec4 | 10644 | rtx piece = gen_rtx (REG, reg_raw_mode[i], i); |
230d793d RS |
10645 | |
10646 | if (reg_referenced_p (piece, PATTERN (place)) | |
10647 | && ! dead_or_set_p (place, piece) | |
10648 | && ! reg_bitfield_target_p (piece, | |
10649 | PATTERN (place))) | |
10650 | REG_NOTES (place) = gen_rtx (EXPR_LIST, REG_DEAD, | |
10651 | piece, | |
10652 | REG_NOTES (place)); | |
10653 | } | |
10654 | ||
10655 | place = 0; | |
10656 | } | |
10657 | } | |
10658 | } | |
10659 | break; | |
10660 | ||
10661 | default: | |
10662 | /* Any other notes should not be present at this point in the | |
10663 | compilation. */ | |
10664 | abort (); | |
10665 | } | |
10666 | ||
10667 | if (place) | |
10668 | { | |
10669 | XEXP (note, 1) = REG_NOTES (place); | |
10670 | REG_NOTES (place) = note; | |
10671 | } | |
1a26b032 RK |
10672 | else if ((REG_NOTE_KIND (note) == REG_DEAD |
10673 | || REG_NOTE_KIND (note) == REG_UNUSED) | |
10674 | && GET_CODE (XEXP (note, 0)) == REG) | |
10675 | reg_n_deaths[REGNO (XEXP (note, 0))]--; | |
230d793d RS |
10676 | |
10677 | if (place2) | |
1a26b032 RK |
10678 | { |
10679 | if ((REG_NOTE_KIND (note) == REG_DEAD | |
10680 | || REG_NOTE_KIND (note) == REG_UNUSED) | |
10681 | && GET_CODE (XEXP (note, 0)) == REG) | |
10682 | reg_n_deaths[REGNO (XEXP (note, 0))]++; | |
10683 | ||
10684 | REG_NOTES (place2) = gen_rtx (GET_CODE (note), REG_NOTE_KIND (note), | |
10685 | XEXP (note, 0), REG_NOTES (place2)); | |
10686 | } | |
230d793d RS |
10687 | } |
10688 | } | |
10689 | \f | |
10690 | /* Similarly to above, distribute the LOG_LINKS that used to be present on | |
5089e22e RS |
10691 | I3, I2, and I1 to new locations. This is also called in one case to |
10692 | add a link pointing at I3 when I3's destination is changed. */ | |
230d793d RS |
10693 | |
10694 | static void | |
10695 | distribute_links (links) | |
10696 | rtx links; | |
10697 | { | |
10698 | rtx link, next_link; | |
10699 | ||
10700 | for (link = links; link; link = next_link) | |
10701 | { | |
10702 | rtx place = 0; | |
10703 | rtx insn; | |
10704 | rtx set, reg; | |
10705 | ||
10706 | next_link = XEXP (link, 1); | |
10707 | ||
10708 | /* If the insn that this link points to is a NOTE or isn't a single | |
10709 | set, ignore it. In the latter case, it isn't clear what we | |
10710 | can do other than ignore the link, since we can't tell which | |
10711 | register it was for. Such links wouldn't be used by combine | |
10712 | anyway. | |
10713 | ||
10714 | It is not possible for the destination of the target of the link to | |
10715 | have been changed by combine. The only potential of this is if we | |
10716 | replace I3, I2, and I1 by I3 and I2. But in that case the | |
10717 | destination of I2 also remains unchanged. */ | |
10718 | ||
10719 | if (GET_CODE (XEXP (link, 0)) == NOTE | |
10720 | || (set = single_set (XEXP (link, 0))) == 0) | |
10721 | continue; | |
10722 | ||
10723 | reg = SET_DEST (set); | |
10724 | while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT | |
10725 | || GET_CODE (reg) == SIGN_EXTRACT | |
10726 | || GET_CODE (reg) == STRICT_LOW_PART) | |
10727 | reg = XEXP (reg, 0); | |
10728 | ||
10729 | /* A LOG_LINK is defined as being placed on the first insn that uses | |
10730 | a register and points to the insn that sets the register. Start | |
10731 | searching at the next insn after the target of the link and stop | |
10732 | when we reach a set of the register or the end of the basic block. | |
10733 | ||
10734 | Note that this correctly handles the link that used to point from | |
5089e22e | 10735 | I3 to I2. Also note that not much searching is typically done here |
230d793d RS |
10736 | since most links don't point very far away. */ |
10737 | ||
10738 | for (insn = NEXT_INSN (XEXP (link, 0)); | |
0d4d42c3 RK |
10739 | (insn && (this_basic_block == n_basic_blocks - 1 |
10740 | || basic_block_head[this_basic_block + 1] != insn)); | |
230d793d RS |
10741 | insn = NEXT_INSN (insn)) |
10742 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
10743 | && reg_overlap_mentioned_p (reg, PATTERN (insn))) | |
10744 | { | |
10745 | if (reg_referenced_p (reg, PATTERN (insn))) | |
10746 | place = insn; | |
10747 | break; | |
10748 | } | |
6e2d1486 RK |
10749 | else if (GET_CODE (insn) == CALL_INSN |
10750 | && find_reg_fusage (insn, USE, reg)) | |
10751 | { | |
10752 | place = insn; | |
10753 | break; | |
10754 | } | |
230d793d RS |
10755 | |
10756 | /* If we found a place to put the link, place it there unless there | |
10757 | is already a link to the same insn as LINK at that point. */ | |
10758 | ||
10759 | if (place) | |
10760 | { | |
10761 | rtx link2; | |
10762 | ||
10763 | for (link2 = LOG_LINKS (place); link2; link2 = XEXP (link2, 1)) | |
10764 | if (XEXP (link2, 0) == XEXP (link, 0)) | |
10765 | break; | |
10766 | ||
10767 | if (link2 == 0) | |
10768 | { | |
10769 | XEXP (link, 1) = LOG_LINKS (place); | |
10770 | LOG_LINKS (place) = link; | |
abe6e52f RK |
10771 | |
10772 | /* Set added_links_insn to the earliest insn we added a | |
10773 | link to. */ | |
10774 | if (added_links_insn == 0 | |
10775 | || INSN_CUID (added_links_insn) > INSN_CUID (place)) | |
10776 | added_links_insn = place; | |
230d793d RS |
10777 | } |
10778 | } | |
10779 | } | |
10780 | } | |
10781 | \f | |
10782 | void | |
10783 | dump_combine_stats (file) | |
10784 | FILE *file; | |
10785 | { | |
10786 | fprintf | |
10787 | (file, | |
10788 | ";; Combiner statistics: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n\n", | |
10789 | combine_attempts, combine_merges, combine_extras, combine_successes); | |
10790 | } | |
10791 | ||
10792 | void | |
10793 | dump_combine_total_stats (file) | |
10794 | FILE *file; | |
10795 | { | |
10796 | fprintf | |
10797 | (file, | |
10798 | "\n;; Combiner totals: %d attempts, %d substitutions (%d requiring new space),\n;; %d successes.\n", | |
10799 | total_attempts, total_merges, total_extras, total_successes); | |
10800 | } |