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2bbd3819 RS |
1 | /* Allocate registers within a basic block, for GNU compiler. |
2 | Copyright (C) 1987, 1988, 1991 Free Software Foundation, Inc. | |
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 | /* Allocation of hard register numbers to pseudo registers is done in | |
22 | two passes. In this pass we consider only regs that are born and | |
23 | die once within one basic block. We do this one basic block at a | |
24 | time. Then the next pass allocates the registers that remain. | |
25 | Two passes are used because this pass uses methods that work only | |
26 | on linear code, but that do a better job than the general methods | |
27 | used in global_alloc, and more quickly too. | |
28 | ||
29 | The assignments made are recorded in the vector reg_renumber | |
30 | whose space is allocated here. The rtl code itself is not altered. | |
31 | ||
32 | We assign each instruction in the basic block a number | |
33 | which is its order from the beginning of the block. | |
34 | Then we can represent the lifetime of a pseudo register with | |
35 | a pair of numbers, and check for conflicts easily. | |
36 | We can record the availability of hard registers with a | |
37 | HARD_REG_SET for each instruction. The HARD_REG_SET | |
38 | contains 0 or 1 for each hard reg. | |
39 | ||
40 | To avoid register shuffling, we tie registers together when one | |
41 | dies by being copied into another, or dies in an instruction that | |
42 | does arithmetic to produce another. The tied registers are | |
43 | allocated as one. Registers with different reg class preferences | |
44 | can never be tied unless the class preferred by one is a subclass | |
45 | of the one preferred by the other. | |
46 | ||
47 | Tying is represented with "quantity numbers". | |
48 | A non-tied register is given a new quantity number. | |
49 | Tied registers have the same quantity number. | |
50 | ||
51 | We have provision to exempt registers, even when they are contained | |
52 | within the block, that can be tied to others that are not contained in it. | |
53 | This is so that global_alloc could process them both and tie them then. | |
54 | But this is currently disabled since tying in global_alloc is not | |
55 | yet implemented. */ | |
56 | ||
57 | #include <stdio.h> | |
58 | #include "config.h" | |
59 | #include "rtl.h" | |
60 | #include "flags.h" | |
61 | #include "basic-block.h" | |
62 | #include "regs.h" | |
63 | #include "hard-reg-set.h" | |
64 | #include "insn-config.h" | |
65 | #include "recog.h" | |
66 | #include "output.h" | |
67 | \f | |
cde62d1a RK |
68 | /* Pseudos allocated here cannot be reallocated by global.c if the hard |
69 | register is used as a spill register. So we don't allocate such pseudos | |
70 | here if their preferred class is likely to be used by spills. | |
71 | ||
72 | On most machines, the appropriate test is if the class has one | |
73 | register, so we default to that. */ | |
74 | ||
75 | #ifndef CLASS_LIKELY_SPILLED_P | |
76 | #define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) | |
77 | #endif | |
78 | ||
2bbd3819 RS |
79 | /* Next quantity number available for allocation. */ |
80 | ||
81 | static int next_qty; | |
82 | ||
83 | /* In all the following vectors indexed by quantity number. */ | |
84 | ||
85 | /* Element Q is the hard reg number chosen for quantity Q, | |
86 | or -1 if none was found. */ | |
87 | ||
88 | static short *qty_phys_reg; | |
89 | ||
90 | /* We maintain two hard register sets that indicate suggested hard registers | |
91 | for each quantity. The first, qty_phys_copy_sugg, contains hard registers | |
92 | that are tied to the quantity by a simple copy. The second contains all | |
93 | hard registers that are tied to the quantity via an arithmetic operation. | |
94 | ||
95 | The former register set is given priority for allocation. This tends to | |
96 | eliminate copy insns. */ | |
97 | ||
98 | /* Element Q is a set of hard registers that are suggested for quantity Q by | |
99 | copy insns. */ | |
100 | ||
101 | static HARD_REG_SET *qty_phys_copy_sugg; | |
102 | ||
103 | /* Element Q is a set of hard registers that are suggested for quantity Q by | |
104 | arithmetic insns. */ | |
105 | ||
106 | static HARD_REG_SET *qty_phys_sugg; | |
107 | ||
108 | /* Element Q is non-zero if there is a suggested register in | |
109 | qty_phys_copy_sugg. */ | |
110 | ||
111 | static char *qty_phys_has_copy_sugg; | |
112 | ||
113 | /* Element Q is non-zero if there is a suggested register in qty_phys_sugg. */ | |
114 | ||
115 | static char *qty_phys_has_sugg; | |
116 | ||
117 | /* Element Q is the number of refs to quantity Q. */ | |
118 | ||
aabf56ce | 119 | static int *qty_n_refs; |
2bbd3819 RS |
120 | |
121 | /* Element Q is a reg class contained in (smaller than) the | |
122 | preferred classes of all the pseudo regs that are tied in quantity Q. | |
123 | This is the preferred class for allocating that quantity. */ | |
124 | ||
125 | static enum reg_class *qty_min_class; | |
126 | ||
127 | /* Insn number (counting from head of basic block) | |
128 | where quantity Q was born. -1 if birth has not been recorded. */ | |
129 | ||
130 | static int *qty_birth; | |
131 | ||
132 | /* Insn number (counting from head of basic block) | |
133 | where quantity Q died. Due to the way tying is done, | |
134 | and the fact that we consider in this pass only regs that die but once, | |
135 | a quantity can die only once. Each quantity's life span | |
136 | is a set of consecutive insns. -1 if death has not been recorded. */ | |
137 | ||
138 | static int *qty_death; | |
139 | ||
140 | /* Number of words needed to hold the data in quantity Q. | |
141 | This depends on its machine mode. It is used for these purposes: | |
142 | 1. It is used in computing the relative importances of qtys, | |
143 | which determines the order in which we look for regs for them. | |
144 | 2. It is used in rules that prevent tying several registers of | |
145 | different sizes in a way that is geometrically impossible | |
146 | (see combine_regs). */ | |
147 | ||
148 | static int *qty_size; | |
149 | ||
150 | /* This holds the mode of the registers that are tied to qty Q, | |
151 | or VOIDmode if registers with differing modes are tied together. */ | |
152 | ||
153 | static enum machine_mode *qty_mode; | |
154 | ||
155 | /* Number of times a reg tied to qty Q lives across a CALL_INSN. */ | |
156 | ||
157 | static int *qty_n_calls_crossed; | |
158 | ||
e4600702 RK |
159 | /* Register class within which we allocate qty Q if we can't get |
160 | its preferred class. */ | |
2bbd3819 | 161 | |
e4600702 | 162 | static enum reg_class *qty_alternate_class; |
2bbd3819 RS |
163 | |
164 | /* Element Q is the SCRATCH expression for which this quantity is being | |
165 | allocated or 0 if this quantity is allocating registers. */ | |
166 | ||
167 | static rtx *qty_scratch_rtx; | |
168 | ||
169 | /* Element Q is the register number of one pseudo register whose | |
170 | reg_qty value is Q, or -1 is this quantity is for a SCRATCH. This | |
171 | register should be the head of the chain maintained in reg_next_in_qty. */ | |
172 | ||
aabf56ce | 173 | static int *qty_first_reg; |
2bbd3819 RS |
174 | |
175 | /* If (REG N) has been assigned a quantity number, is a register number | |
176 | of another register assigned the same quantity number, or -1 for the | |
177 | end of the chain. qty_first_reg point to the head of this chain. */ | |
178 | ||
aabf56ce | 179 | static int *reg_next_in_qty; |
2bbd3819 RS |
180 | |
181 | /* reg_qty[N] (where N is a pseudo reg number) is the qty number of that reg | |
182 | if it is >= 0, | |
183 | of -1 if this register cannot be allocated by local-alloc, | |
184 | or -2 if not known yet. | |
185 | ||
186 | Note that if we see a use or death of pseudo register N with | |
187 | reg_qty[N] == -2, register N must be local to the current block. If | |
188 | it were used in more than one block, we would have reg_qty[N] == -1. | |
189 | This relies on the fact that if reg_basic_block[N] is >= 0, register N | |
190 | will not appear in any other block. We save a considerable number of | |
191 | tests by exploiting this. | |
192 | ||
193 | If N is < FIRST_PSEUDO_REGISTER, reg_qty[N] is undefined and should not | |
194 | be referenced. */ | |
195 | ||
196 | static int *reg_qty; | |
197 | ||
198 | /* The offset (in words) of register N within its quantity. | |
199 | This can be nonzero if register N is SImode, and has been tied | |
200 | to a subreg of a DImode register. */ | |
201 | ||
202 | static char *reg_offset; | |
203 | ||
204 | /* Vector of substitutions of register numbers, | |
205 | used to map pseudo regs into hardware regs. | |
206 | This is set up as a result of register allocation. | |
207 | Element N is the hard reg assigned to pseudo reg N, | |
208 | or is -1 if no hard reg was assigned. | |
209 | If N is a hard reg number, element N is N. */ | |
210 | ||
211 | short *reg_renumber; | |
212 | ||
213 | /* Set of hard registers live at the current point in the scan | |
214 | of the instructions in a basic block. */ | |
215 | ||
216 | static HARD_REG_SET regs_live; | |
217 | ||
218 | /* Each set of hard registers indicates registers live at a particular | |
219 | point in the basic block. For N even, regs_live_at[N] says which | |
220 | hard registers are needed *after* insn N/2 (i.e., they may not | |
221 | conflict with the outputs of insn N/2 or the inputs of insn N/2 + 1. | |
222 | ||
223 | If an object is to conflict with the inputs of insn J but not the | |
224 | outputs of insn J + 1, we say it is born at index J*2 - 1. Similarly, | |
225 | if it is to conflict with the outputs of insn J but not the inputs of | |
226 | insn J + 1, it is said to die at index J*2 + 1. */ | |
227 | ||
228 | static HARD_REG_SET *regs_live_at; | |
229 | ||
230 | /* Communicate local vars `insn_number' and `insn' | |
231 | from `block_alloc' to `reg_is_set', `wipe_dead_reg', and `alloc_qty'. */ | |
232 | static int this_insn_number; | |
233 | static rtx this_insn; | |
234 | ||
235 | static void block_alloc (); | |
236 | static void update_equiv_regs (); | |
237 | static int no_conflict_p (); | |
238 | static int combine_regs (); | |
239 | static void wipe_dead_reg (); | |
240 | static int find_free_reg (); | |
241 | static void reg_is_born (); | |
242 | static void reg_is_set (); | |
243 | static void mark_life (); | |
244 | static void post_mark_life (); | |
245 | static int qty_compare (); | |
246 | static int qty_compare_1 (); | |
247 | static int reg_meets_class_p (); | |
248 | static void update_qty_class (); | |
249 | static int requires_inout_p (); | |
250 | \f | |
251 | /* Allocate a new quantity (new within current basic block) | |
252 | for register number REGNO which is born at index BIRTH | |
253 | within the block. MODE and SIZE are info on reg REGNO. */ | |
254 | ||
255 | static void | |
256 | alloc_qty (regno, mode, size, birth) | |
257 | int regno; | |
258 | enum machine_mode mode; | |
259 | int size, birth; | |
260 | { | |
261 | register int qty = next_qty++; | |
262 | ||
263 | reg_qty[regno] = qty; | |
264 | reg_offset[regno] = 0; | |
265 | reg_next_in_qty[regno] = -1; | |
266 | ||
267 | qty_first_reg[qty] = regno; | |
268 | qty_size[qty] = size; | |
269 | qty_mode[qty] = mode; | |
270 | qty_birth[qty] = birth; | |
271 | qty_n_calls_crossed[qty] = reg_n_calls_crossed[regno]; | |
272 | qty_min_class[qty] = reg_preferred_class (regno); | |
e4600702 | 273 | qty_alternate_class[qty] = reg_alternate_class (regno); |
2bbd3819 RS |
274 | qty_n_refs[qty] = reg_n_refs[regno]; |
275 | } | |
276 | \f | |
277 | /* Similar to `alloc_qty', but allocates a quantity for a SCRATCH rtx | |
278 | used as operand N in INSN. We assume here that the SCRATCH is used in | |
279 | a CLOBBER. */ | |
280 | ||
281 | static void | |
282 | alloc_qty_for_scratch (scratch, n, insn, insn_code_num, insn_number) | |
283 | rtx scratch; | |
284 | int n; | |
285 | rtx insn; | |
286 | int insn_code_num, insn_number; | |
287 | { | |
288 | register int qty; | |
289 | enum reg_class class; | |
290 | char *p, c; | |
291 | int i; | |
292 | ||
7fe4336e | 293 | #ifdef REGISTER_CONSTRAINTS |
2bbd3819 RS |
294 | /* If we haven't yet computed which alternative will be used, do so now. |
295 | Then set P to the constraints for that alternative. */ | |
296 | if (which_alternative == -1) | |
297 | if (! constrain_operands (insn_code_num, 0)) | |
298 | return; | |
299 | ||
300 | for (p = insn_operand_constraint[insn_code_num][n], i = 0; | |
301 | *p && i < which_alternative; p++) | |
302 | if (*p == ',') | |
303 | i++; | |
304 | ||
305 | /* Compute the class required for this SCRATCH. If we don't need a | |
306 | register, the class will remain NO_REGS. If we guessed the alternative | |
307 | number incorrectly, reload will fix things up for us. */ | |
308 | ||
309 | class = NO_REGS; | |
310 | while ((c = *p++) != '\0' && c != ',') | |
311 | switch (c) | |
312 | { | |
313 | case '=': case '+': case '?': | |
314 | case '#': case '&': case '!': | |
315 | case '*': case '%': | |
316 | case '0': case '1': case '2': case '3': case '4': | |
317 | case 'm': case '<': case '>': case 'V': case 'o': | |
318 | case 'E': case 'F': case 'G': case 'H': | |
319 | case 's': case 'i': case 'n': | |
320 | case 'I': case 'J': case 'K': case 'L': | |
321 | case 'M': case 'N': case 'O': case 'P': | |
322 | #ifdef EXTRA_CONSTRAINT | |
323 | case 'Q': case 'R': case 'S': case 'T': case 'U': | |
324 | #endif | |
325 | case 'p': | |
326 | /* These don't say anything we care about. */ | |
327 | break; | |
328 | ||
329 | case 'X': | |
330 | /* We don't need to allocate this SCRATCH. */ | |
331 | return; | |
332 | ||
333 | case 'g': case 'r': | |
334 | class = reg_class_subunion[(int) class][(int) GENERAL_REGS]; | |
335 | break; | |
336 | ||
337 | default: | |
338 | class | |
339 | = reg_class_subunion[(int) class][(int) REG_CLASS_FROM_LETTER (c)]; | |
340 | break; | |
341 | } | |
342 | ||
cde62d1a | 343 | /* If CLASS has only a few registers, don't allocate the SCRATCH here since |
2bbd3819 RS |
344 | it will prevent that register from being used as a spill register. |
345 | reload will do the allocation. */ | |
346 | ||
cde62d1a | 347 | if (class == NO_REGS || CLASS_LIKELY_SPILLED_P (class)) |
2bbd3819 RS |
348 | return; |
349 | ||
7fe4336e RK |
350 | #else /* REGISTER_CONSTRAINTS */ |
351 | ||
352 | class = GENERAL_REGS; | |
353 | #endif | |
354 | ||
355 | ||
2bbd3819 RS |
356 | qty = next_qty++; |
357 | ||
358 | qty_first_reg[qty] = -1; | |
359 | qty_scratch_rtx[qty] = scratch; | |
360 | qty_size[qty] = GET_MODE_SIZE (GET_MODE (scratch)); | |
361 | qty_mode[qty] = GET_MODE (scratch); | |
362 | qty_birth[qty] = 2 * insn_number - 1; | |
363 | qty_death[qty] = 2 * insn_number + 1; | |
364 | qty_n_calls_crossed[qty] = 0; | |
365 | qty_min_class[qty] = class; | |
e4600702 | 366 | qty_alternate_class[qty] = NO_REGS; |
2bbd3819 RS |
367 | qty_n_refs[qty] = 1; |
368 | } | |
369 | \f | |
370 | /* Main entry point of this file. */ | |
371 | ||
372 | void | |
373 | local_alloc () | |
374 | { | |
375 | register int b, i; | |
376 | int max_qty; | |
377 | ||
378 | /* Leaf functions and non-leaf functions have different needs. | |
379 | If defined, let the machine say what kind of ordering we | |
380 | should use. */ | |
381 | #ifdef ORDER_REGS_FOR_LOCAL_ALLOC | |
382 | ORDER_REGS_FOR_LOCAL_ALLOC; | |
383 | #endif | |
384 | ||
385 | /* Promote REG_EQUAL notes to REG_EQUIV notes and adjust status of affected | |
386 | registers. */ | |
387 | update_equiv_regs (); | |
388 | ||
389 | /* This sets the maximum number of quantities we can have. Quantity | |
d45cf215 | 390 | numbers start at zero and we can have one for each pseudo plus the |
6dc42e49 | 391 | number of SCRATCHes in the largest block, in the worst case. */ |
2bbd3819 RS |
392 | max_qty = (max_regno - FIRST_PSEUDO_REGISTER) + max_scratch; |
393 | ||
394 | /* Allocate vectors of temporary data. | |
395 | See the declarations of these variables, above, | |
396 | for what they mean. */ | |
397 | ||
398 | qty_phys_reg = (short *) alloca (max_qty * sizeof (short)); | |
399 | qty_phys_copy_sugg = (HARD_REG_SET *) alloca (max_qty * sizeof (HARD_REG_SET)); | |
400 | qty_phys_has_copy_sugg = (char *) alloca (max_qty * sizeof (char)); | |
401 | qty_phys_sugg = (HARD_REG_SET *) alloca (max_qty * sizeof (HARD_REG_SET)); | |
402 | qty_phys_has_sugg = (char *) alloca (max_qty * sizeof (char)); | |
403 | qty_birth = (int *) alloca (max_qty * sizeof (int)); | |
404 | qty_death = (int *) alloca (max_qty * sizeof (int)); | |
405 | qty_scratch_rtx = (rtx *) alloca (max_qty * sizeof (rtx)); | |
aabf56ce | 406 | qty_first_reg = (int *) alloca (max_qty * sizeof (int)); |
2bbd3819 RS |
407 | qty_size = (int *) alloca (max_qty * sizeof (int)); |
408 | qty_mode = (enum machine_mode *) alloca (max_qty * sizeof (enum machine_mode)); | |
409 | qty_n_calls_crossed = (int *) alloca (max_qty * sizeof (int)); | |
410 | qty_min_class = (enum reg_class *) alloca (max_qty * sizeof (enum reg_class)); | |
e4600702 | 411 | qty_alternate_class = (enum reg_class *) alloca (max_qty * sizeof (enum reg_class)); |
aabf56ce | 412 | qty_n_refs = (int *) alloca (max_qty * sizeof (int)); |
2bbd3819 RS |
413 | |
414 | reg_qty = (int *) alloca (max_regno * sizeof (int)); | |
415 | reg_offset = (char *) alloca (max_regno * sizeof (char)); | |
aabf56ce | 416 | reg_next_in_qty = (int *) alloca (max_regno * sizeof (int)); |
2bbd3819 RS |
417 | |
418 | reg_renumber = (short *) oballoc (max_regno * sizeof (short)); | |
419 | for (i = 0; i < max_regno; i++) | |
420 | reg_renumber[i] = -1; | |
421 | ||
422 | /* Determine which pseudo-registers can be allocated by local-alloc. | |
423 | In general, these are the registers used only in a single block and | |
424 | which only die once. However, if a register's preferred class has only | |
cde62d1a | 425 | a few entries, don't allocate this register here unless it is preferred |
2bbd3819 RS |
426 | or nothing since retry_global_alloc won't be able to move it to |
427 | GENERAL_REGS if a reload register of this class is needed. | |
428 | ||
429 | We need not be concerned with which block actually uses the register | |
430 | since we will never see it outside that block. */ | |
431 | ||
432 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
433 | { | |
434 | if (reg_basic_block[i] >= 0 && reg_n_deaths[i] == 1 | |
e4600702 | 435 | && (reg_alternate_class (i) == NO_REGS |
cde62d1a | 436 | || ! CLASS_LIKELY_SPILLED_P (reg_preferred_class (i)))) |
2bbd3819 RS |
437 | reg_qty[i] = -2; |
438 | else | |
439 | reg_qty[i] = -1; | |
440 | } | |
441 | ||
442 | /* Force loop below to initialize entire quantity array. */ | |
443 | next_qty = max_qty; | |
444 | ||
445 | /* Allocate each block's local registers, block by block. */ | |
446 | ||
447 | for (b = 0; b < n_basic_blocks; b++) | |
448 | { | |
449 | /* NEXT_QTY indicates which elements of the `qty_...' | |
450 | vectors might need to be initialized because they were used | |
451 | for the previous block; it is set to the entire array before | |
452 | block 0. Initialize those, with explicit loop if there are few, | |
453 | else with bzero and bcopy. Do not initialize vectors that are | |
454 | explicit set by `alloc_qty'. */ | |
455 | ||
456 | if (next_qty < 6) | |
457 | { | |
458 | for (i = 0; i < next_qty; i++) | |
459 | { | |
460 | qty_scratch_rtx[i] = 0; | |
461 | CLEAR_HARD_REG_SET (qty_phys_copy_sugg[i]); | |
462 | qty_phys_has_copy_sugg[i] = 0; | |
463 | CLEAR_HARD_REG_SET (qty_phys_sugg[i]); | |
464 | qty_phys_has_sugg[i] = 0; | |
465 | } | |
466 | } | |
467 | else | |
468 | { | |
469 | #define CLEAR(vector) \ | |
470 | bzero ((vector), (sizeof (*(vector))) * next_qty); | |
471 | ||
472 | CLEAR (qty_scratch_rtx); | |
473 | CLEAR (qty_phys_copy_sugg); | |
474 | CLEAR (qty_phys_has_copy_sugg); | |
475 | CLEAR (qty_phys_sugg); | |
476 | CLEAR (qty_phys_has_sugg); | |
477 | } | |
478 | ||
479 | next_qty = 0; | |
480 | ||
481 | block_alloc (b); | |
482 | #ifdef USE_C_ALLOCA | |
483 | alloca (0); | |
484 | #endif | |
485 | } | |
486 | } | |
487 | \f | |
488 | /* Depth of loops we are in while in update_equiv_regs. */ | |
489 | static int loop_depth; | |
490 | ||
491 | /* Used for communication between the following two functions: contains | |
492 | a MEM that we wish to ensure remains unchanged. */ | |
493 | static rtx equiv_mem; | |
494 | ||
495 | /* Set nonzero if EQUIV_MEM is modified. */ | |
496 | static int equiv_mem_modified; | |
497 | ||
498 | /* If EQUIV_MEM is modified by modifying DEST, indicate that it is modified. | |
499 | Called via note_stores. */ | |
500 | ||
501 | static void | |
502 | validate_equiv_mem_from_store (dest, set) | |
503 | rtx dest; | |
504 | rtx set; | |
505 | { | |
506 | if ((GET_CODE (dest) == REG | |
507 | && reg_overlap_mentioned_p (dest, equiv_mem)) | |
508 | || (GET_CODE (dest) == MEM | |
509 | && true_dependence (dest, equiv_mem))) | |
510 | equiv_mem_modified = 1; | |
511 | } | |
512 | ||
513 | /* Verify that no store between START and the death of REG invalidates | |
514 | MEMREF. MEMREF is invalidated by modifying a register used in MEMREF, | |
515 | by storing into an overlapping memory location, or with a non-const | |
516 | CALL_INSN. | |
517 | ||
518 | Return 1 if MEMREF remains valid. */ | |
519 | ||
520 | static int | |
521 | validate_equiv_mem (start, reg, memref) | |
522 | rtx start; | |
523 | rtx reg; | |
524 | rtx memref; | |
525 | { | |
526 | rtx insn; | |
527 | rtx note; | |
528 | ||
529 | equiv_mem = memref; | |
530 | equiv_mem_modified = 0; | |
531 | ||
532 | /* If the memory reference has side effects or is volatile, it isn't a | |
533 | valid equivalence. */ | |
534 | if (side_effects_p (memref)) | |
535 | return 0; | |
536 | ||
537 | for (insn = start; insn && ! equiv_mem_modified; insn = NEXT_INSN (insn)) | |
538 | { | |
539 | if (GET_RTX_CLASS (GET_CODE (insn)) != 'i') | |
540 | continue; | |
541 | ||
542 | if (find_reg_note (insn, REG_DEAD, reg)) | |
543 | return 1; | |
544 | ||
545 | if (GET_CODE (insn) == CALL_INSN && ! RTX_UNCHANGING_P (memref) | |
546 | && ! CONST_CALL_P (insn)) | |
547 | return 0; | |
548 | ||
549 | note_stores (PATTERN (insn), validate_equiv_mem_from_store); | |
550 | ||
551 | /* If a register mentioned in MEMREF is modified via an | |
552 | auto-increment, we lose the equivalence. Do the same if one | |
553 | dies; although we could extend the life, it doesn't seem worth | |
554 | the trouble. */ | |
555 | ||
556 | for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
557 | if ((REG_NOTE_KIND (note) == REG_INC | |
558 | || REG_NOTE_KIND (note) == REG_DEAD) | |
559 | && GET_CODE (XEXP (note, 0)) == REG | |
560 | && reg_overlap_mentioned_p (XEXP (note, 0), memref)) | |
561 | return 0; | |
562 | } | |
563 | ||
564 | return 0; | |
565 | } | |
566 | \f | |
567 | /* TRUE if X references a memory location that would be affected by a store | |
568 | to MEMREF. */ | |
569 | ||
570 | static int | |
571 | memref_referenced_p (memref, x) | |
572 | rtx x; | |
573 | rtx memref; | |
574 | { | |
575 | int i, j; | |
576 | char *fmt; | |
577 | enum rtx_code code = GET_CODE (x); | |
578 | ||
579 | switch (code) | |
580 | { | |
581 | case REG: | |
582 | case CONST_INT: | |
583 | case CONST: | |
584 | case LABEL_REF: | |
585 | case SYMBOL_REF: | |
586 | case CONST_DOUBLE: | |
587 | case PC: | |
588 | case CC0: | |
589 | case HIGH: | |
590 | case LO_SUM: | |
591 | return 0; | |
592 | ||
593 | case MEM: | |
594 | if (true_dependence (memref, x)) | |
595 | return 1; | |
596 | break; | |
597 | ||
598 | case SET: | |
599 | /* If we are setting a MEM, it doesn't count (its address does), but any | |
600 | other SET_DEST that has a MEM in it is referencing the MEM. */ | |
601 | if (GET_CODE (SET_DEST (x)) == MEM) | |
602 | { | |
603 | if (memref_referenced_p (memref, XEXP (SET_DEST (x), 0))) | |
604 | return 1; | |
605 | } | |
606 | else if (memref_referenced_p (memref, SET_DEST (x))) | |
607 | return 1; | |
608 | ||
609 | return memref_referenced_p (memref, SET_SRC (x)); | |
610 | } | |
611 | ||
612 | fmt = GET_RTX_FORMAT (code); | |
613 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
614 | switch (fmt[i]) | |
615 | { | |
616 | case 'e': | |
617 | if (memref_referenced_p (memref, XEXP (x, i))) | |
618 | return 1; | |
619 | break; | |
620 | case 'E': | |
621 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
622 | if (memref_referenced_p (memref, XVECEXP (x, i, j))) | |
623 | return 1; | |
624 | break; | |
625 | } | |
626 | ||
627 | return 0; | |
628 | } | |
629 | ||
630 | /* TRUE if some insn in the range (START, END] references a memory location | |
631 | that would be affected by a store to MEMREF. */ | |
632 | ||
633 | static int | |
634 | memref_used_between_p (memref, start, end) | |
635 | rtx memref; | |
636 | rtx start; | |
637 | rtx end; | |
638 | { | |
639 | rtx insn; | |
640 | ||
641 | for (insn = NEXT_INSN (start); insn != NEXT_INSN (end); | |
642 | insn = NEXT_INSN (insn)) | |
643 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
644 | && memref_referenced_p (memref, PATTERN (insn))) | |
645 | return 1; | |
646 | ||
647 | return 0; | |
648 | } | |
649 | \f | |
650 | /* INSN is a copy from SRC to DEST, both registers, and SRC does not die | |
651 | in INSN. | |
652 | ||
653 | Search forward to see if SRC dies before either it or DEST is modified, | |
654 | but don't scan past the end of a basic block. If so, we can replace SRC | |
655 | with DEST and let SRC die in INSN. | |
656 | ||
657 | This will reduce the number of registers live in that range and may enable | |
658 | DEST to be tied to SRC, thus often saving one register in addition to a | |
659 | register-register copy. */ | |
660 | ||
661 | static void | |
d45cf215 | 662 | optimize_reg_copy_1 (insn, dest, src) |
2bbd3819 RS |
663 | rtx insn; |
664 | rtx dest; | |
665 | rtx src; | |
666 | { | |
667 | rtx p, q; | |
668 | rtx note; | |
669 | rtx dest_death = 0; | |
670 | int sregno = REGNO (src); | |
671 | int dregno = REGNO (dest); | |
672 | ||
673 | if (sregno == dregno | |
674 | #ifdef SMALL_REGISTER_CLASSES | |
675 | /* We don't want to mess with hard regs if register classes are small. */ | |
676 | || sregno < FIRST_PSEUDO_REGISTER || dregno < FIRST_PSEUDO_REGISTER | |
677 | #endif | |
678 | /* We don't see all updates to SP if they are in an auto-inc memory | |
679 | reference, so we must disallow this optimization on them. */ | |
680 | || sregno == STACK_POINTER_REGNUM || dregno == STACK_POINTER_REGNUM) | |
681 | return; | |
682 | ||
683 | for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p)) | |
684 | { | |
685 | if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN | |
686 | || (GET_CODE (p) == NOTE | |
687 | && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG | |
688 | || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) | |
689 | break; | |
690 | ||
691 | if (GET_RTX_CLASS (GET_CODE (p)) != 'i') | |
692 | continue; | |
693 | ||
694 | if (reg_set_p (src, p) || reg_set_p (dest, p) | |
695 | /* Don't change a USE of a register. */ | |
696 | || (GET_CODE (PATTERN (p)) == USE | |
697 | && reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0)))) | |
698 | break; | |
699 | ||
d9983d6c RK |
700 | /* See if all of SRC dies in P. This test is slightly more |
701 | conservative than it needs to be. */ | |
702 | if ((note = find_regno_note (p, REG_DEAD, sregno)) != 0 | |
703 | && GET_MODE (XEXP (note, 0)) == GET_MODE (src)) | |
2bbd3819 RS |
704 | { |
705 | int failed = 0; | |
706 | int length = 0; | |
d9983d6c | 707 | int d_length = 0; |
2bbd3819 | 708 | int n_calls = 0; |
d9983d6c | 709 | int d_n_calls = 0; |
2bbd3819 RS |
710 | |
711 | /* We can do the optimization. Scan forward from INSN again, | |
712 | replacing regs as we go. Set FAILED if a replacement can't | |
713 | be done. In that case, we can't move the death note for SRC. | |
714 | This should be rare. */ | |
715 | ||
716 | /* Set to stop at next insn. */ | |
717 | for (q = next_real_insn (insn); | |
718 | q != next_real_insn (p); | |
719 | q = next_real_insn (q)) | |
720 | { | |
d9983d6c | 721 | if (reg_overlap_mentioned_p (src, PATTERN (q))) |
2bbd3819 | 722 | { |
d9983d6c RK |
723 | /* If SRC is a hard register, we might miss some |
724 | overlapping registers with validate_replace_rtx, | |
725 | so we would have to undo it. We can't if DEST is | |
726 | present in the insn, so fail in that combination | |
727 | of cases. */ | |
728 | if (sregno < FIRST_PSEUDO_REGISTER | |
729 | && reg_mentioned_p (dest, PATTERN (q))) | |
730 | failed = 1; | |
731 | ||
732 | /* Replace all uses and make sure that the register | |
733 | isn't still present. */ | |
734 | else if (validate_replace_rtx (src, dest, q) | |
735 | && (sregno >= FIRST_PSEUDO_REGISTER | |
736 | || ! reg_overlap_mentioned_p (src, | |
737 | PATTERN (q)))) | |
2bbd3819 RS |
738 | { |
739 | /* We assume that a register is used exactly once per | |
740 | insn in the updates below. If this is not correct, | |
741 | no great harm is done. */ | |
742 | if (sregno >= FIRST_PSEUDO_REGISTER) | |
743 | reg_n_refs[sregno] -= loop_depth; | |
744 | if (dregno >= FIRST_PSEUDO_REGISTER) | |
745 | reg_n_refs[dregno] += loop_depth; | |
746 | } | |
747 | else | |
d9983d6c RK |
748 | { |
749 | validate_replace_rtx (dest, src, q); | |
750 | failed = 1; | |
751 | } | |
2bbd3819 RS |
752 | } |
753 | ||
754 | /* Count the insns and CALL_INSNs passed. If we passed the | |
755 | death note of DEST, show increased live length. */ | |
756 | length++; | |
757 | if (dest_death) | |
d9983d6c | 758 | d_length++; |
2bbd3819 RS |
759 | |
760 | if (GET_CODE (q) == CALL_INSN) | |
761 | { | |
762 | n_calls++; | |
763 | if (dest_death) | |
d9983d6c | 764 | d_n_calls++; |
2bbd3819 RS |
765 | } |
766 | ||
767 | /* If DEST dies here, remove the death note and save it for | |
d9983d6c RK |
768 | later. Make sure ALL of DEST dies here; again, this is |
769 | overly conservative. */ | |
2bbd3819 | 770 | if (dest_death == 0 |
d9983d6c RK |
771 | && (dest_death = find_regno_note (q, REG_DEAD, dregno)) != 0 |
772 | && GET_MODE (XEXP (dest_death, 0)) == GET_MODE (dest)) | |
2bbd3819 RS |
773 | remove_note (q, dest_death); |
774 | } | |
775 | ||
776 | if (! failed) | |
777 | { | |
778 | if (sregno >= FIRST_PSEUDO_REGISTER) | |
779 | { | |
780 | reg_live_length[sregno] -= length; | |
781 | reg_n_calls_crossed[sregno] -= n_calls; | |
782 | } | |
783 | ||
d9983d6c RK |
784 | if (dregno >= FIRST_PSEUDO_REGISTER) |
785 | { | |
786 | reg_live_length[dregno] += d_length; | |
787 | reg_n_calls_crossed[dregno] += d_n_calls; | |
788 | } | |
789 | ||
2bbd3819 RS |
790 | /* Move death note of SRC from P to INSN. */ |
791 | remove_note (p, note); | |
792 | XEXP (note, 1) = REG_NOTES (insn); | |
793 | REG_NOTES (insn) = note; | |
794 | } | |
795 | ||
796 | /* Put death note of DEST on P if we saw it die. */ | |
797 | if (dest_death) | |
798 | { | |
799 | XEXP (dest_death, 1) = REG_NOTES (p); | |
800 | REG_NOTES (p) = dest_death; | |
801 | } | |
802 | ||
803 | return; | |
804 | } | |
d9983d6c RK |
805 | |
806 | /* If SRC is a hard register which is set or killed in some other | |
807 | way, we can't do this optimization. */ | |
808 | else if (sregno < FIRST_PSEUDO_REGISTER | |
809 | && dead_or_set_p (p, src)) | |
810 | break; | |
2bbd3819 RS |
811 | } |
812 | } | |
d45cf215 RS |
813 | \f |
814 | /* INSN is a copy of SRC to DEST, in which SRC dies. See if we now have | |
815 | a sequence of insns that modify DEST followed by an insn that sets | |
816 | SRC to DEST in which DEST dies, with no prior modification of DEST. | |
817 | (There is no need to check if the insns in between actually modify | |
818 | DEST. We should not have cases where DEST is not modified, but | |
819 | the optimization is safe if no such modification is detected.) | |
820 | In that case, we can replace all uses of DEST, starting with INSN and | |
821 | ending with the set of SRC to DEST, with SRC. We do not do this | |
822 | optimization if a CALL_INSN is crossed unless SRC already crosses a | |
823 | call. | |
824 | ||
825 | It is assumed that DEST and SRC are pseudos; it is too complicated to do | |
826 | this for hard registers since the substitutions we may make might fail. */ | |
827 | ||
828 | static void | |
829 | optimize_reg_copy_2 (insn, dest, src) | |
830 | rtx insn; | |
831 | rtx dest; | |
832 | rtx src; | |
833 | { | |
834 | rtx p, q; | |
835 | rtx set; | |
836 | int sregno = REGNO (src); | |
837 | int dregno = REGNO (dest); | |
838 | ||
839 | for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p)) | |
840 | { | |
841 | if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN | |
842 | || (GET_CODE (p) == NOTE | |
843 | && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG | |
844 | || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) | |
845 | break; | |
846 | ||
847 | if (GET_RTX_CLASS (GET_CODE (p)) != 'i') | |
848 | continue; | |
849 | ||
850 | set = single_set (p); | |
851 | if (set && SET_SRC (set) == dest && SET_DEST (set) == src | |
852 | && find_reg_note (p, REG_DEAD, dest)) | |
853 | { | |
854 | /* We can do the optimization. Scan forward from INSN again, | |
855 | replacing regs as we go. */ | |
856 | ||
857 | /* Set to stop at next insn. */ | |
858 | for (q = insn; q != NEXT_INSN (p); q = NEXT_INSN (q)) | |
859 | if (GET_RTX_CLASS (GET_CODE (q)) == 'i') | |
860 | { | |
861 | if (reg_mentioned_p (dest, PATTERN (q))) | |
862 | { | |
863 | PATTERN (q) = replace_rtx (PATTERN (q), dest, src); | |
864 | ||
865 | /* We assume that a register is used exactly once per | |
866 | insn in the updates below. If this is not correct, | |
867 | no great harm is done. */ | |
6102fe95 JW |
868 | reg_n_refs[dregno] -= loop_depth; |
869 | reg_n_refs[sregno] += loop_depth; | |
d45cf215 RS |
870 | } |
871 | ||
872 | ||
873 | if (GET_CODE (q) == CALL_INSN) | |
874 | { | |
875 | reg_n_calls_crossed[dregno]--; | |
876 | reg_n_calls_crossed[sregno]++; | |
877 | } | |
878 | } | |
879 | ||
880 | remove_note (p, find_reg_note (p, REG_DEAD, dest)); | |
881 | reg_n_deaths[dregno]--; | |
882 | remove_note (insn, find_reg_note (insn, REG_DEAD, src)); | |
883 | reg_n_deaths[sregno]--; | |
884 | return; | |
885 | } | |
886 | ||
887 | if (reg_set_p (src, p) | |
888 | || (GET_CODE (p) == CALL_INSN && reg_n_calls_crossed[sregno] == 0)) | |
889 | break; | |
890 | } | |
891 | } | |
2bbd3819 RS |
892 | \f |
893 | /* Find registers that are equivalent to a single value throughout the | |
894 | compilation (either because they can be referenced in memory or are set once | |
895 | from a single constant). Lower their priority for a register. | |
896 | ||
897 | If such a register is only referenced once, try substituting its value | |
898 | into the using insn. If it succeeds, we can eliminate the register | |
899 | completely. */ | |
900 | ||
901 | static void | |
902 | update_equiv_regs () | |
903 | { | |
904 | rtx *reg_equiv_init_insn = (rtx *) alloca (max_regno * sizeof (rtx *)); | |
905 | rtx *reg_equiv_replacement = (rtx *) alloca (max_regno * sizeof (rtx *)); | |
906 | rtx insn; | |
907 | ||
908 | bzero (reg_equiv_init_insn, max_regno * sizeof (rtx *)); | |
909 | bzero (reg_equiv_replacement, max_regno * sizeof (rtx *)); | |
910 | ||
911 | init_alias_analysis (); | |
912 | ||
913 | loop_depth = 1; | |
914 | ||
915 | /* Scan the insns and find which registers have equivalences. Do this | |
916 | in a separate scan of the insns because (due to -fcse-follow-jumps) | |
917 | a register can be set below its use. */ | |
918 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
919 | { | |
920 | rtx note; | |
921 | rtx set = single_set (insn); | |
922 | rtx dest; | |
923 | int regno; | |
924 | ||
925 | if (GET_CODE (insn) == NOTE) | |
926 | { | |
927 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
928 | loop_depth++; | |
929 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
930 | loop_depth--; | |
931 | } | |
932 | ||
933 | /* If this insn contains more (or less) than a single SET, ignore it. */ | |
934 | if (set == 0) | |
935 | continue; | |
936 | ||
937 | dest = SET_DEST (set); | |
938 | ||
939 | /* If this sets a MEM to the contents of a REG that is only used | |
940 | in a single basic block, see if the register is always equivalent | |
941 | to that memory location and if moving the store from INSN to the | |
942 | insn that set REG is safe. If so, put a REG_EQUIV note on the | |
943 | initializing insn. */ | |
944 | ||
945 | if (GET_CODE (dest) == MEM && GET_CODE (SET_SRC (set)) == REG | |
946 | && (regno = REGNO (SET_SRC (set))) >= FIRST_PSEUDO_REGISTER | |
947 | && reg_basic_block[regno] >= 0 | |
948 | && reg_equiv_init_insn[regno] != 0 | |
949 | && validate_equiv_mem (reg_equiv_init_insn[regno], SET_SRC (set), | |
950 | dest) | |
951 | && ! memref_used_between_p (SET_DEST (set), | |
952 | reg_equiv_init_insn[regno], insn)) | |
953 | REG_NOTES (reg_equiv_init_insn[regno]) | |
954 | = gen_rtx (EXPR_LIST, REG_EQUIV, dest, | |
955 | REG_NOTES (reg_equiv_init_insn[regno])); | |
956 | ||
957 | /* If this is a register-register copy where SRC is not dead, see if we | |
958 | can optimize it. */ | |
959 | if (flag_expensive_optimizations && GET_CODE (dest) == REG | |
960 | && GET_CODE (SET_SRC (set)) == REG | |
961 | && ! find_reg_note (insn, REG_DEAD, SET_SRC (set))) | |
d45cf215 RS |
962 | optimize_reg_copy_1 (insn, dest, SET_SRC (set)); |
963 | ||
964 | /* Similarly for a pseudo-pseudo copy when SRC is dead. */ | |
965 | else if (flag_expensive_optimizations && GET_CODE (dest) == REG | |
966 | && REGNO (dest) >= FIRST_PSEUDO_REGISTER | |
967 | && GET_CODE (SET_SRC (set)) == REG | |
968 | && REGNO (SET_SRC (set)) >= FIRST_PSEUDO_REGISTER | |
969 | && find_reg_note (insn, REG_DEAD, SET_SRC (set))) | |
970 | optimize_reg_copy_2 (insn, dest, SET_SRC (set)); | |
2bbd3819 RS |
971 | |
972 | /* Otherwise, we only handle the case of a pseudo register being set | |
973 | once. */ | |
974 | if (GET_CODE (dest) != REG | |
975 | || (regno = REGNO (dest)) < FIRST_PSEUDO_REGISTER | |
976 | || reg_n_sets[regno] != 1) | |
977 | continue; | |
978 | ||
b1ec3c92 | 979 | note = find_reg_note (insn, REG_EQUAL, NULL_RTX); |
2bbd3819 RS |
980 | |
981 | /* Record this insn as initializing this register. */ | |
982 | reg_equiv_init_insn[regno] = insn; | |
983 | ||
984 | /* If this register is known to be equal to a constant, record that | |
985 | it is always equivalent to the constant. */ | |
986 | if (note && CONSTANT_P (XEXP (note, 0))) | |
987 | PUT_MODE (note, (enum machine_mode) REG_EQUIV); | |
988 | ||
989 | /* If this insn introduces a "constant" register, decrease the priority | |
990 | of that register. Record this insn if the register is only used once | |
991 | more and the equivalence value is the same as our source. | |
992 | ||
993 | The latter condition is checked for two reasons: First, it is an | |
994 | indication that it may be more efficient to actually emit the insn | |
995 | as written (if no registers are available, reload will substitute | |
996 | the equivalence). Secondly, it avoids problems with any registers | |
997 | dying in this insn whose death notes would be missed. | |
998 | ||
999 | If we don't have a REG_EQUIV note, see if this insn is loading | |
1000 | a register used only in one basic block from a MEM. If so, and the | |
1001 | MEM remains unchanged for the life of the register, add a REG_EQUIV | |
1002 | note. */ | |
1003 | ||
b1ec3c92 | 1004 | note = find_reg_note (insn, REG_EQUIV, NULL_RTX); |
2bbd3819 RS |
1005 | |
1006 | if (note == 0 && reg_basic_block[regno] >= 0 | |
1007 | && GET_CODE (SET_SRC (set)) == MEM | |
1008 | && validate_equiv_mem (insn, dest, SET_SRC (set))) | |
1009 | REG_NOTES (insn) = note = gen_rtx (EXPR_LIST, REG_EQUIV, SET_SRC (set), | |
1010 | REG_NOTES (insn)); | |
1011 | ||
1012 | /* Don't mess with things live during setjmp. */ | |
1013 | if (note && reg_live_length[regno] >= 0) | |
1014 | { | |
1015 | int regno = REGNO (dest); | |
1016 | ||
1017 | /* Note that the statement below does not affect the priority | |
1018 | in local-alloc! */ | |
1019 | reg_live_length[regno] *= 2; | |
1020 | ||
1021 | /* If the register is referenced exactly twice, meaning it is set | |
1022 | once and used once, indicate that the reference may be replaced | |
1023 | by the equivalence we computed above. If the register is only | |
1024 | used in one basic block, this can't succeed or combine would | |
1025 | have done it. | |
1026 | ||
1027 | It would be nice to use "loop_depth * 2" in the compare | |
1028 | below. Unfortunately, LOOP_DEPTH need not be constant within | |
1029 | a basic block so this would be too complicated. | |
1030 | ||
1031 | This case normally occurs when a parameter is read from memory | |
1032 | and then used exactly once, not in a loop. */ | |
1033 | ||
1034 | if (reg_n_refs[regno] == 2 | |
1035 | && reg_basic_block[regno] < 0 | |
1036 | && rtx_equal_p (XEXP (note, 0), SET_SRC (set))) | |
1037 | reg_equiv_replacement[regno] = SET_SRC (set); | |
1038 | } | |
1039 | } | |
1040 | ||
1041 | /* Now scan all regs killed in an insn to see if any of them are registers | |
1042 | only used that once. If so, see if we can replace the reference with | |
1043 | the equivalent from. If we can, delete the initializing reference | |
1044 | and this register will go away. */ | |
1045 | for (insn = next_active_insn (get_insns ()); | |
1046 | insn; | |
1047 | insn = next_active_insn (insn)) | |
1048 | { | |
1049 | rtx link; | |
1050 | ||
1051 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
1052 | if (REG_NOTE_KIND (link) == REG_DEAD | |
1053 | /* Make sure this insn still refers to the register. */ | |
1054 | && reg_mentioned_p (XEXP (link, 0), PATTERN (insn))) | |
1055 | { | |
1056 | int regno = REGNO (XEXP (link, 0)); | |
1057 | ||
1058 | if (reg_equiv_replacement[regno] | |
1059 | && validate_replace_rtx (regno_reg_rtx[regno], | |
1060 | reg_equiv_replacement[regno], insn)) | |
1061 | { | |
1062 | rtx equiv_insn = reg_equiv_init_insn[regno]; | |
1063 | ||
1064 | remove_death (regno, insn); | |
1065 | reg_n_refs[regno] = 0; | |
1066 | PUT_CODE (equiv_insn, NOTE); | |
1067 | NOTE_LINE_NUMBER (equiv_insn) = NOTE_INSN_DELETED; | |
1068 | NOTE_SOURCE_FILE (equiv_insn) = 0; | |
1069 | } | |
1070 | } | |
1071 | } | |
1072 | } | |
1073 | \f | |
1074 | /* Allocate hard regs to the pseudo regs used only within block number B. | |
1075 | Only the pseudos that die but once can be handled. */ | |
1076 | ||
1077 | static void | |
1078 | block_alloc (b) | |
1079 | int b; | |
1080 | { | |
1081 | register int i, q; | |
1082 | register rtx insn; | |
1083 | rtx note; | |
1084 | int insn_number = 0; | |
1085 | int insn_count = 0; | |
1086 | int max_uid = get_max_uid (); | |
aabf56ce | 1087 | int *qty_order; |
2bbd3819 RS |
1088 | int no_conflict_combined_regno = -1; |
1089 | ||
1090 | /* Count the instructions in the basic block. */ | |
1091 | ||
1092 | insn = basic_block_end[b]; | |
1093 | while (1) | |
1094 | { | |
1095 | if (GET_CODE (insn) != NOTE) | |
1096 | if (++insn_count > max_uid) | |
1097 | abort (); | |
1098 | if (insn == basic_block_head[b]) | |
1099 | break; | |
1100 | insn = PREV_INSN (insn); | |
1101 | } | |
1102 | ||
1103 | /* +2 to leave room for a post_mark_life at the last insn and for | |
1104 | the birth of a CLOBBER in the first insn. */ | |
1105 | regs_live_at = (HARD_REG_SET *) alloca ((2 * insn_count + 2) | |
1106 | * sizeof (HARD_REG_SET)); | |
1107 | bzero (regs_live_at, (2 * insn_count + 2) * sizeof (HARD_REG_SET)); | |
1108 | ||
1109 | /* Initialize table of hardware registers currently live. */ | |
1110 | ||
1111 | #ifdef HARD_REG_SET | |
1112 | regs_live = *basic_block_live_at_start[b]; | |
1113 | #else | |
1114 | COPY_HARD_REG_SET (regs_live, basic_block_live_at_start[b]); | |
1115 | #endif | |
1116 | ||
1117 | /* This loop scans the instructions of the basic block | |
1118 | and assigns quantities to registers. | |
1119 | It computes which registers to tie. */ | |
1120 | ||
1121 | insn = basic_block_head[b]; | |
1122 | while (1) | |
1123 | { | |
1124 | register rtx body = PATTERN (insn); | |
1125 | ||
1126 | if (GET_CODE (insn) != NOTE) | |
1127 | insn_number++; | |
1128 | ||
1129 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') | |
1130 | { | |
1131 | register rtx link, set; | |
1132 | register int win = 0; | |
1133 | register rtx r0, r1; | |
1134 | int combined_regno = -1; | |
1135 | int i; | |
1136 | int insn_code_number = recog_memoized (insn); | |
1137 | ||
1138 | this_insn_number = insn_number; | |
1139 | this_insn = insn; | |
1140 | ||
1141 | if (insn_code_number >= 0) | |
1142 | insn_extract (insn); | |
1143 | which_alternative = -1; | |
1144 | ||
1145 | /* Is this insn suitable for tying two registers? | |
1146 | If so, try doing that. | |
1147 | Suitable insns are those with at least two operands and where | |
1148 | operand 0 is an output that is a register that is not | |
1149 | earlyclobber. | |
7aba0f0b RK |
1150 | |
1151 | We can tie operand 0 with some operand that dies in this insn. | |
1152 | First look for operands that are required to be in the same | |
1153 | register as operand 0. If we find such, only try tying that | |
1154 | operand or one that can be put into that operand if the | |
1155 | operation is commutative. If we don't find an operand | |
1156 | that is required to be in the same register as operand 0, | |
1157 | we can tie with any operand. | |
1158 | ||
2bbd3819 RS |
1159 | Subregs in place of regs are also ok. |
1160 | ||
1161 | If tying is done, WIN is set nonzero. */ | |
1162 | ||
1163 | if (insn_code_number >= 0 | |
7fe4336e | 1164 | #ifdef REGISTER_CONSTRAINTS |
2bbd3819 RS |
1165 | && insn_n_operands[insn_code_number] > 1 |
1166 | && insn_operand_constraint[insn_code_number][0][0] == '=' | |
7fe4336e RK |
1167 | && insn_operand_constraint[insn_code_number][0][1] != '&' |
1168 | #else | |
1169 | && GET_CODE (PATTERN (insn)) == SET | |
1170 | && rtx_equal_p (SET_DEST (PATTERN (insn)), recog_operand[0]) | |
1171 | #endif | |
1172 | ) | |
2bbd3819 | 1173 | { |
7fe4336e | 1174 | #ifdef REGISTER_CONSTRAINTS |
7aba0f0b RK |
1175 | int must_match_0 = -1; |
1176 | ||
1177 | ||
1178 | for (i = 1; i < insn_n_operands[insn_code_number]; i++) | |
1179 | if (requires_inout_p | |
1180 | (insn_operand_constraint[insn_code_number][i])) | |
1181 | must_match_0 = i; | |
7fe4336e | 1182 | #endif |
2bbd3819 | 1183 | |
7aba0f0b RK |
1184 | r0 = recog_operand[0]; |
1185 | for (i = 1; i < insn_n_operands[insn_code_number]; i++) | |
2bbd3819 | 1186 | { |
7fe4336e | 1187 | #ifdef REGISTER_CONSTRAINTS |
7aba0f0b RK |
1188 | /* Skip this operand if we found an operand that |
1189 | must match operand 0 and this operand isn't it | |
1190 | and can't be made to be it by commutativity. */ | |
1191 | ||
1192 | if (must_match_0 >= 0 && i != must_match_0 | |
1193 | && ! (i == must_match_0 + 1 | |
1194 | && insn_operand_constraint[insn_code_number][i-1][0] == '%') | |
1195 | && ! (i == must_match_0 - 1 | |
1196 | && insn_operand_constraint[insn_code_number][i][0] == '%')) | |
1197 | continue; | |
7fe4336e | 1198 | #endif |
2bbd3819 | 1199 | |
7aba0f0b | 1200 | r1 = recog_operand[i]; |
2bbd3819 | 1201 | |
7aba0f0b RK |
1202 | /* If the operand is an address, find a register in it. |
1203 | There may be more than one register, but we only try one | |
1204 | of them. */ | |
1205 | if ( | |
7fe4336e | 1206 | #ifdef REGISTER_CONSTRAINTS |
7aba0f0b | 1207 | insn_operand_constraint[insn_code_number][i][0] == 'p' |
7fe4336e | 1208 | #else |
7aba0f0b | 1209 | insn_operand_address_p[insn_code_number][i] |
7fe4336e | 1210 | #endif |
7aba0f0b RK |
1211 | ) |
1212 | while (GET_CODE (r1) == PLUS || GET_CODE (r1) == MULT) | |
1213 | r1 = XEXP (r1, 0); | |
1214 | ||
1215 | if (GET_CODE (r0) == REG || GET_CODE (r0) == SUBREG) | |
1216 | { | |
1217 | /* We have two priorities for hard register preferences. | |
1218 | If we have a move insn or an insn whose first input | |
1219 | can only be in the same register as the output, give | |
1220 | priority to an equivalence found from that insn. */ | |
1221 | int may_save_copy | |
1222 | = ((SET_DEST (body) == r0 && SET_SRC (body) == r1) | |
1223 | #ifdef REGISTER_CONSTRAINTS | |
1224 | || (r1 == recog_operand[i] && must_match_0 >= 0) | |
1225 | #endif | |
1226 | ); | |
1227 | ||
1228 | if (GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG) | |
1229 | win = combine_regs (r1, r0, may_save_copy, | |
1230 | insn_number, insn, 0); | |
1231 | } | |
2bbd3819 RS |
1232 | } |
1233 | } | |
1234 | ||
1235 | /* Recognize an insn sequence with an ultimate result | |
1236 | which can safely overlap one of the inputs. | |
1237 | The sequence begins with a CLOBBER of its result, | |
1238 | and ends with an insn that copies the result to itself | |
1239 | and has a REG_EQUAL note for an equivalent formula. | |
1240 | That note indicates what the inputs are. | |
1241 | The result and the input can overlap if each insn in | |
1242 | the sequence either doesn't mention the input | |
1243 | or has a REG_NO_CONFLICT note to inhibit the conflict. | |
1244 | ||
1245 | We do the combining test at the CLOBBER so that the | |
1246 | destination register won't have had a quantity number | |
1247 | assigned, since that would prevent combining. */ | |
1248 | ||
1249 | if (GET_CODE (PATTERN (insn)) == CLOBBER | |
1250 | && (r0 = XEXP (PATTERN (insn), 0), | |
1251 | GET_CODE (r0) == REG) | |
b1ec3c92 | 1252 | && (link = find_reg_note (insn, REG_LIBCALL, NULL_RTX)) != 0 |
2bbd3819 RS |
1253 | && GET_CODE (XEXP (link, 0)) == INSN |
1254 | && (set = single_set (XEXP (link, 0))) != 0 | |
1255 | && SET_DEST (set) == r0 && SET_SRC (set) == r0 | |
b1ec3c92 CH |
1256 | && (note = find_reg_note (XEXP (link, 0), REG_EQUAL, |
1257 | NULL_RTX)) != 0) | |
2bbd3819 RS |
1258 | { |
1259 | if (r1 = XEXP (note, 0), GET_CODE (r1) == REG | |
1260 | /* Check that we have such a sequence. */ | |
1261 | && no_conflict_p (insn, r0, r1)) | |
1262 | win = combine_regs (r1, r0, 1, insn_number, insn, 1); | |
1263 | else if (GET_RTX_FORMAT (GET_CODE (XEXP (note, 0)))[0] == 'e' | |
1264 | && (r1 = XEXP (XEXP (note, 0), 0), | |
1265 | GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG) | |
1266 | && no_conflict_p (insn, r0, r1)) | |
1267 | win = combine_regs (r1, r0, 0, insn_number, insn, 1); | |
1268 | ||
1269 | /* Here we care if the operation to be computed is | |
1270 | commutative. */ | |
1271 | else if ((GET_CODE (XEXP (note, 0)) == EQ | |
1272 | || GET_CODE (XEXP (note, 0)) == NE | |
1273 | || GET_RTX_CLASS (GET_CODE (XEXP (note, 0))) == 'c') | |
1274 | && (r1 = XEXP (XEXP (note, 0), 1), | |
1275 | (GET_CODE (r1) == REG || GET_CODE (r1) == SUBREG)) | |
1276 | && no_conflict_p (insn, r0, r1)) | |
1277 | win = combine_regs (r1, r0, 0, insn_number, insn, 1); | |
1278 | ||
1279 | /* If we did combine something, show the register number | |
1280 | in question so that we know to ignore its death. */ | |
1281 | if (win) | |
1282 | no_conflict_combined_regno = REGNO (r1); | |
1283 | } | |
1284 | ||
1285 | /* If registers were just tied, set COMBINED_REGNO | |
1286 | to the number of the register used in this insn | |
1287 | that was tied to the register set in this insn. | |
1288 | This register's qty should not be "killed". */ | |
1289 | ||
1290 | if (win) | |
1291 | { | |
1292 | while (GET_CODE (r1) == SUBREG) | |
1293 | r1 = SUBREG_REG (r1); | |
1294 | combined_regno = REGNO (r1); | |
1295 | } | |
1296 | ||
1297 | /* Mark the death of everything that dies in this instruction, | |
1298 | except for anything that was just combined. */ | |
1299 | ||
1300 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
1301 | if (REG_NOTE_KIND (link) == REG_DEAD | |
1302 | && GET_CODE (XEXP (link, 0)) == REG | |
1303 | && combined_regno != REGNO (XEXP (link, 0)) | |
1304 | && (no_conflict_combined_regno != REGNO (XEXP (link, 0)) | |
1305 | || ! find_reg_note (insn, REG_NO_CONFLICT, XEXP (link, 0)))) | |
1306 | wipe_dead_reg (XEXP (link, 0), 0); | |
1307 | ||
1308 | /* Allocate qty numbers for all registers local to this block | |
1309 | that are born (set) in this instruction. | |
1310 | A pseudo that already has a qty is not changed. */ | |
1311 | ||
1312 | note_stores (PATTERN (insn), reg_is_set); | |
1313 | ||
1314 | /* If anything is set in this insn and then unused, mark it as dying | |
1315 | after this insn, so it will conflict with our outputs. This | |
1316 | can't match with something that combined, and it doesn't matter | |
1317 | if it did. Do this after the calls to reg_is_set since these | |
1318 | die after, not during, the current insn. */ | |
1319 | ||
1320 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) | |
1321 | if (REG_NOTE_KIND (link) == REG_UNUSED | |
1322 | && GET_CODE (XEXP (link, 0)) == REG) | |
1323 | wipe_dead_reg (XEXP (link, 0), 1); | |
1324 | ||
1325 | #ifndef SMALL_REGISTER_CLASSES | |
1326 | /* Allocate quantities for any SCRATCH operands of this insn. We | |
1327 | don't do this for machines with small register classes because | |
1328 | those machines can use registers explicitly mentioned in the | |
1329 | RTL as spill registers and our usage of hard registers | |
1330 | explicitly for SCRATCH operands will conflict. On those machines, | |
1331 | reload will allocate the SCRATCH. */ | |
1332 | ||
1333 | if (insn_code_number >= 0) | |
1334 | for (i = 0; i < insn_n_operands[insn_code_number]; i++) | |
1335 | if (GET_CODE (recog_operand[i]) == SCRATCH) | |
1336 | alloc_qty_for_scratch (recog_operand[i], i, insn, | |
1337 | insn_code_number, insn_number); | |
1338 | #endif | |
1339 | ||
1340 | /* If this is an insn that has a REG_RETVAL note pointing at a | |
1341 | CLOBBER insn, we have reached the end of a REG_NO_CONFLICT | |
1342 | block, so clear any register number that combined within it. */ | |
b1ec3c92 | 1343 | if ((note = find_reg_note (insn, REG_RETVAL, NULL_RTX)) != 0 |
2bbd3819 RS |
1344 | && GET_CODE (XEXP (note, 0)) == INSN |
1345 | && GET_CODE (PATTERN (XEXP (note, 0))) == CLOBBER) | |
1346 | no_conflict_combined_regno = -1; | |
1347 | } | |
1348 | ||
1349 | /* Set the registers live after INSN_NUMBER. Note that we never | |
1350 | record the registers live before the block's first insn, since no | |
1351 | pseudos we care about are live before that insn. */ | |
1352 | ||
1353 | IOR_HARD_REG_SET (regs_live_at[2 * insn_number], regs_live); | |
1354 | IOR_HARD_REG_SET (regs_live_at[2 * insn_number + 1], regs_live); | |
1355 | ||
1356 | if (insn == basic_block_end[b]) | |
1357 | break; | |
1358 | ||
1359 | insn = NEXT_INSN (insn); | |
1360 | } | |
1361 | ||
1362 | /* Now every register that is local to this basic block | |
1363 | should have been given a quantity, or else -1 meaning ignore it. | |
1364 | Every quantity should have a known birth and death. | |
1365 | ||
1366 | Order the qtys so we assign them registers in order of | |
1367 | decreasing length of life. Normally call qsort, but if we | |
1368 | have only a very small number of quantities, sort them ourselves. */ | |
1369 | ||
aabf56ce | 1370 | qty_order = (int *) alloca (next_qty * sizeof (int)); |
2bbd3819 RS |
1371 | for (i = 0; i < next_qty; i++) |
1372 | qty_order[i] = i; | |
1373 | ||
1374 | #define EXCHANGE(I1, I2) \ | |
1375 | { i = qty_order[I1]; qty_order[I1] = qty_order[I2]; qty_order[I2] = i; } | |
1376 | ||
1377 | switch (next_qty) | |
1378 | { | |
1379 | case 3: | |
1380 | /* Make qty_order[2] be the one to allocate last. */ | |
1381 | if (qty_compare (0, 1) > 0) | |
1382 | EXCHANGE (0, 1); | |
1383 | if (qty_compare (1, 2) > 0) | |
1384 | EXCHANGE (2, 1); | |
1385 | ||
1386 | /* ... Fall through ... */ | |
1387 | case 2: | |
1388 | /* Put the best one to allocate in qty_order[0]. */ | |
1389 | if (qty_compare (0, 1) > 0) | |
1390 | EXCHANGE (0, 1); | |
1391 | ||
1392 | /* ... Fall through ... */ | |
1393 | ||
1394 | case 1: | |
1395 | case 0: | |
1396 | /* Nothing to do here. */ | |
1397 | break; | |
1398 | ||
1399 | default: | |
aabf56ce | 1400 | qsort (qty_order, next_qty, sizeof (int), qty_compare_1); |
2bbd3819 RS |
1401 | } |
1402 | ||
1403 | /* Try to put each quantity in a suggested physical register, if it has one. | |
1404 | This may cause registers to be allocated that otherwise wouldn't be, but | |
1405 | this seems acceptable in local allocation (unlike global allocation). */ | |
1406 | for (i = 0; i < next_qty; i++) | |
1407 | { | |
1408 | q = qty_order[i]; | |
1409 | if (qty_phys_has_sugg[q] || qty_phys_has_copy_sugg[q]) | |
1410 | qty_phys_reg[q] = find_free_reg (qty_min_class[q], qty_mode[q], q, | |
1411 | 0, 1, qty_birth[q], qty_death[q]); | |
1412 | else | |
1413 | qty_phys_reg[q] = -1; | |
1414 | } | |
1415 | ||
1416 | /* Now for each qty that is not a hardware register, | |
1417 | look for a hardware register to put it in. | |
1418 | First try the register class that is cheapest for this qty, | |
1419 | if there is more than one class. */ | |
1420 | ||
1421 | for (i = 0; i < next_qty; i++) | |
1422 | { | |
1423 | q = qty_order[i]; | |
1424 | if (qty_phys_reg[q] < 0) | |
1425 | { | |
1426 | if (N_REG_CLASSES > 1) | |
1427 | { | |
1428 | qty_phys_reg[q] = find_free_reg (qty_min_class[q], | |
1429 | qty_mode[q], q, 0, 0, | |
1430 | qty_birth[q], qty_death[q]); | |
1431 | if (qty_phys_reg[q] >= 0) | |
1432 | continue; | |
1433 | } | |
1434 | ||
e4600702 RK |
1435 | if (qty_alternate_class[q] != NO_REGS) |
1436 | qty_phys_reg[q] = find_free_reg (qty_alternate_class[q], | |
2bbd3819 RS |
1437 | qty_mode[q], q, 0, 0, |
1438 | qty_birth[q], qty_death[q]); | |
1439 | } | |
1440 | } | |
1441 | ||
1442 | /* Now propagate the register assignments | |
1443 | to the pseudo regs belonging to the qtys. */ | |
1444 | ||
1445 | for (q = 0; q < next_qty; q++) | |
1446 | if (qty_phys_reg[q] >= 0) | |
1447 | { | |
1448 | for (i = qty_first_reg[q]; i >= 0; i = reg_next_in_qty[i]) | |
1449 | reg_renumber[i] = qty_phys_reg[q] + reg_offset[i]; | |
1450 | if (qty_scratch_rtx[q]) | |
1451 | { | |
1452 | PUT_CODE (qty_scratch_rtx[q], REG); | |
1453 | REGNO (qty_scratch_rtx[q]) = qty_phys_reg[q]; | |
1454 | ||
1455 | for (i = HARD_REGNO_NREGS (qty_phys_reg[q], | |
1456 | GET_MODE (qty_scratch_rtx[q])) - 1; | |
1457 | i >= 0; i--) | |
1458 | regs_ever_live[qty_phys_reg[q] + i] = 1; | |
1459 | ||
1460 | /* Must clear the USED field, because it will have been set by | |
1461 | copy_rtx_if_shared, but the leaf_register code expects that | |
1462 | it is zero in all REG rtx. copy_rtx_if_shared does not set the | |
1463 | used bit for REGs, but does for SCRATCHes. */ | |
1464 | qty_scratch_rtx[q]->used = 0; | |
1465 | } | |
1466 | } | |
1467 | } | |
1468 | \f | |
1469 | /* Compare two quantities' priority for getting real registers. | |
1470 | We give shorter-lived quantities higher priority. | |
6dc42e49 RS |
1471 | Quantities with more references are also preferred, as are quantities that |
1472 | require multiple registers. This is the identical prioritization as | |
2bbd3819 RS |
1473 | done by global-alloc. |
1474 | ||
1475 | We used to give preference to registers with *longer* lives, but using | |
1476 | the same algorithm in both local- and global-alloc can speed up execution | |
1477 | of some programs by as much as a factor of three! */ | |
1478 | ||
1479 | static int | |
1480 | qty_compare (q1, q2) | |
1481 | int q1, q2; | |
1482 | { | |
1483 | /* Note that the quotient will never be bigger than | |
1484 | the value of floor_log2 times the maximum number of | |
1485 | times a register can occur in one insn (surely less than 100). | |
1486 | Multiplying this by 10000 can't overflow. */ | |
1487 | register int pri1 | |
1488 | = (((double) (floor_log2 (qty_n_refs[q1]) * qty_n_refs[q1]) | |
1489 | / ((qty_death[q1] - qty_birth[q1]) * qty_size[q1])) | |
1490 | * 10000); | |
1491 | register int pri2 | |
1492 | = (((double) (floor_log2 (qty_n_refs[q2]) * qty_n_refs[q2]) | |
1493 | / ((qty_death[q2] - qty_birth[q2]) * qty_size[q2])) | |
1494 | * 10000); | |
1495 | return pri2 - pri1; | |
1496 | } | |
1497 | ||
1498 | static int | |
1499 | qty_compare_1 (q1, q2) | |
aabf56ce | 1500 | int *q1, *q2; |
2bbd3819 RS |
1501 | { |
1502 | register int tem; | |
1503 | ||
1504 | /* Note that the quotient will never be bigger than | |
1505 | the value of floor_log2 times the maximum number of | |
1506 | times a register can occur in one insn (surely less than 100). | |
1507 | Multiplying this by 10000 can't overflow. */ | |
1508 | register int pri1 | |
1509 | = (((double) (floor_log2 (qty_n_refs[*q1]) * qty_n_refs[*q1]) | |
1510 | / ((qty_death[*q1] - qty_birth[*q1]) * qty_size[*q1])) | |
1511 | * 10000); | |
1512 | register int pri2 | |
1513 | = (((double) (floor_log2 (qty_n_refs[*q2]) * qty_n_refs[*q2]) | |
1514 | / ((qty_death[*q2] - qty_birth[*q2]) * qty_size[*q2])) | |
1515 | * 10000); | |
1516 | ||
1517 | tem = pri2 - pri1; | |
1518 | if (tem != 0) return tem; | |
1519 | /* If qtys are equally good, sort by qty number, | |
1520 | so that the results of qsort leave nothing to chance. */ | |
1521 | return *q1 - *q2; | |
1522 | } | |
1523 | \f | |
1524 | /* Attempt to combine the two registers (rtx's) USEDREG and SETREG. | |
1525 | Returns 1 if have done so, or 0 if cannot. | |
1526 | ||
1527 | Combining registers means marking them as having the same quantity | |
1528 | and adjusting the offsets within the quantity if either of | |
1529 | them is a SUBREG). | |
1530 | ||
1531 | We don't actually combine a hard reg with a pseudo; instead | |
1532 | we just record the hard reg as the suggestion for the pseudo's quantity. | |
1533 | If we really combined them, we could lose if the pseudo lives | |
1534 | across an insn that clobbers the hard reg (eg, movstr). | |
1535 | ||
1536 | ALREADY_DEAD is non-zero if USEDREG is known to be dead even though | |
1537 | there is no REG_DEAD note on INSN. This occurs during the processing | |
1538 | of REG_NO_CONFLICT blocks. | |
1539 | ||
1540 | MAY_SAVE_COPYCOPY is non-zero if this insn is simply copying USEDREG to | |
1541 | SETREG or if the input and output must share a register. | |
1542 | In that case, we record a hard reg suggestion in QTY_PHYS_COPY_SUGG. | |
1543 | ||
1544 | There are elaborate checks for the validity of combining. */ | |
1545 | ||
1546 | ||
1547 | static int | |
1548 | combine_regs (usedreg, setreg, may_save_copy, insn_number, insn, already_dead) | |
1549 | rtx usedreg, setreg; | |
1550 | int may_save_copy; | |
1551 | int insn_number; | |
1552 | rtx insn; | |
1553 | int already_dead; | |
1554 | { | |
1555 | register int ureg, sreg; | |
1556 | register int offset = 0; | |
1557 | int usize, ssize; | |
1558 | register int sqty; | |
1559 | ||
1560 | /* Determine the numbers and sizes of registers being used. If a subreg | |
6dc42e49 | 1561 | is present that does not change the entire register, don't consider |
2bbd3819 RS |
1562 | this a copy insn. */ |
1563 | ||
1564 | while (GET_CODE (usedreg) == SUBREG) | |
1565 | { | |
1566 | if (GET_MODE_SIZE (GET_MODE (SUBREG_REG (usedreg))) > UNITS_PER_WORD) | |
1567 | may_save_copy = 0; | |
1568 | offset += SUBREG_WORD (usedreg); | |
1569 | usedreg = SUBREG_REG (usedreg); | |
1570 | } | |
1571 | if (GET_CODE (usedreg) != REG) | |
1572 | return 0; | |
1573 | ureg = REGNO (usedreg); | |
1574 | usize = REG_SIZE (usedreg); | |
1575 | ||
1576 | while (GET_CODE (setreg) == SUBREG) | |
1577 | { | |
1578 | if (GET_MODE_SIZE (GET_MODE (SUBREG_REG (setreg))) > UNITS_PER_WORD) | |
1579 | may_save_copy = 0; | |
1580 | offset -= SUBREG_WORD (setreg); | |
1581 | setreg = SUBREG_REG (setreg); | |
1582 | } | |
1583 | if (GET_CODE (setreg) != REG) | |
1584 | return 0; | |
1585 | sreg = REGNO (setreg); | |
1586 | ssize = REG_SIZE (setreg); | |
1587 | ||
1588 | /* If UREG is a pseudo-register that hasn't already been assigned a | |
1589 | quantity number, it means that it is not local to this block or dies | |
1590 | more than once. In either event, we can't do anything with it. */ | |
1591 | if ((ureg >= FIRST_PSEUDO_REGISTER && reg_qty[ureg] < 0) | |
1592 | /* Do not combine registers unless one fits within the other. */ | |
1593 | || (offset > 0 && usize + offset > ssize) | |
1594 | || (offset < 0 && usize + offset < ssize) | |
1595 | /* Do not combine with a smaller already-assigned object | |
1596 | if that smaller object is already combined with something bigger. */ | |
1597 | || (ssize > usize && ureg >= FIRST_PSEUDO_REGISTER | |
1598 | && usize < qty_size[reg_qty[ureg]]) | |
1599 | /* Can't combine if SREG is not a register we can allocate. */ | |
1600 | || (sreg >= FIRST_PSEUDO_REGISTER && reg_qty[sreg] == -1) | |
1601 | /* Don't combine with a pseudo mentioned in a REG_NO_CONFLICT note. | |
1602 | These have already been taken care of. This probably wouldn't | |
1603 | combine anyway, but don't take any chances. */ | |
1604 | || (ureg >= FIRST_PSEUDO_REGISTER | |
1605 | && find_reg_note (insn, REG_NO_CONFLICT, usedreg)) | |
1606 | /* Don't tie something to itself. In most cases it would make no | |
1607 | difference, but it would screw up if the reg being tied to itself | |
1608 | also dies in this insn. */ | |
1609 | || ureg == sreg | |
1610 | /* Don't try to connect two different hardware registers. */ | |
1611 | || (ureg < FIRST_PSEUDO_REGISTER && sreg < FIRST_PSEUDO_REGISTER) | |
1612 | /* Don't connect two different machine modes if they have different | |
1613 | implications as to which registers may be used. */ | |
1614 | || !MODES_TIEABLE_P (GET_MODE (usedreg), GET_MODE (setreg))) | |
1615 | return 0; | |
1616 | ||
1617 | /* Now, if UREG is a hard reg and SREG is a pseudo, record the hard reg in | |
1618 | qty_phys_sugg for the pseudo instead of tying them. | |
1619 | ||
1620 | Return "failure" so that the lifespan of UREG is terminated here; | |
1621 | that way the two lifespans will be disjoint and nothing will prevent | |
1622 | the pseudo reg from being given this hard reg. */ | |
1623 | ||
1624 | if (ureg < FIRST_PSEUDO_REGISTER) | |
1625 | { | |
1626 | /* Allocate a quantity number so we have a place to put our | |
1627 | suggestions. */ | |
1628 | if (reg_qty[sreg] == -2) | |
1629 | reg_is_born (setreg, 2 * insn_number); | |
1630 | ||
1631 | if (reg_qty[sreg] >= 0) | |
1632 | { | |
1633 | if (may_save_copy) | |
1634 | { | |
1635 | SET_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[sreg]], ureg); | |
1636 | qty_phys_has_copy_sugg[reg_qty[sreg]] = 1; | |
1637 | } | |
1638 | else | |
1639 | { | |
1640 | SET_HARD_REG_BIT (qty_phys_sugg[reg_qty[sreg]], ureg); | |
1641 | qty_phys_has_sugg[reg_qty[sreg]] = 1; | |
1642 | } | |
1643 | } | |
1644 | return 0; | |
1645 | } | |
1646 | ||
1647 | /* Similarly for SREG a hard register and UREG a pseudo register. */ | |
1648 | ||
1649 | if (sreg < FIRST_PSEUDO_REGISTER) | |
1650 | { | |
1651 | if (may_save_copy) | |
1652 | { | |
1653 | SET_HARD_REG_BIT (qty_phys_copy_sugg[reg_qty[ureg]], sreg); | |
1654 | qty_phys_has_copy_sugg[reg_qty[ureg]] = 1; | |
1655 | } | |
1656 | else | |
1657 | { | |
1658 | SET_HARD_REG_BIT (qty_phys_sugg[reg_qty[ureg]], sreg); | |
1659 | qty_phys_has_sugg[reg_qty[ureg]] = 1; | |
1660 | } | |
1661 | return 0; | |
1662 | } | |
1663 | ||
1664 | /* At this point we know that SREG and UREG are both pseudos. | |
1665 | Do nothing if SREG already has a quantity or is a register that we | |
1666 | don't allocate. */ | |
1667 | if (reg_qty[sreg] >= -1 | |
1668 | /* If we are not going to let any regs live across calls, | |
1669 | don't tie a call-crossing reg to a non-call-crossing reg. */ | |
1670 | || (current_function_has_nonlocal_label | |
1671 | && ((reg_n_calls_crossed[ureg] > 0) | |
1672 | != (reg_n_calls_crossed[sreg] > 0)))) | |
1673 | return 0; | |
1674 | ||
1675 | /* We don't already know about SREG, so tie it to UREG | |
1676 | if this is the last use of UREG, provided the classes they want | |
1677 | are compatible. */ | |
1678 | ||
1679 | if ((already_dead || find_regno_note (insn, REG_DEAD, ureg)) | |
1680 | && reg_meets_class_p (sreg, qty_min_class[reg_qty[ureg]])) | |
1681 | { | |
1682 | /* Add SREG to UREG's quantity. */ | |
1683 | sqty = reg_qty[ureg]; | |
1684 | reg_qty[sreg] = sqty; | |
1685 | reg_offset[sreg] = reg_offset[ureg] + offset; | |
1686 | reg_next_in_qty[sreg] = qty_first_reg[sqty]; | |
1687 | qty_first_reg[sqty] = sreg; | |
1688 | ||
1689 | /* If SREG's reg class is smaller, set qty_min_class[SQTY]. */ | |
1690 | update_qty_class (sqty, sreg); | |
1691 | ||
1692 | /* Update info about quantity SQTY. */ | |
1693 | qty_n_calls_crossed[sqty] += reg_n_calls_crossed[sreg]; | |
1694 | qty_n_refs[sqty] += reg_n_refs[sreg]; | |
2bbd3819 RS |
1695 | if (usize < ssize) |
1696 | { | |
1697 | register int i; | |
1698 | ||
1699 | for (i = qty_first_reg[sqty]; i >= 0; i = reg_next_in_qty[i]) | |
1700 | reg_offset[i] -= offset; | |
1701 | ||
1702 | qty_size[sqty] = ssize; | |
1703 | qty_mode[sqty] = GET_MODE (setreg); | |
1704 | } | |
1705 | } | |
1706 | else | |
1707 | return 0; | |
1708 | ||
1709 | return 1; | |
1710 | } | |
1711 | \f | |
1712 | /* Return 1 if the preferred class of REG allows it to be tied | |
1713 | to a quantity or register whose class is CLASS. | |
1714 | True if REG's reg class either contains or is contained in CLASS. */ | |
1715 | ||
1716 | static int | |
1717 | reg_meets_class_p (reg, class) | |
1718 | int reg; | |
1719 | enum reg_class class; | |
1720 | { | |
1721 | register enum reg_class rclass = reg_preferred_class (reg); | |
1722 | return (reg_class_subset_p (rclass, class) | |
1723 | || reg_class_subset_p (class, rclass)); | |
1724 | } | |
1725 | ||
1726 | /* Return 1 if the two specified classes have registers in common. | |
1727 | If CALL_SAVED, then consider only call-saved registers. */ | |
1728 | ||
1729 | static int | |
1730 | reg_classes_overlap_p (c1, c2, call_saved) | |
1731 | register enum reg_class c1; | |
1732 | register enum reg_class c2; | |
1733 | int call_saved; | |
1734 | { | |
1735 | HARD_REG_SET c; | |
1736 | int i; | |
1737 | ||
1738 | COPY_HARD_REG_SET (c, reg_class_contents[(int) c1]); | |
1739 | AND_HARD_REG_SET (c, reg_class_contents[(int) c2]); | |
1740 | ||
1741 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1742 | if (TEST_HARD_REG_BIT (c, i) | |
1743 | && (! call_saved || ! call_used_regs[i])) | |
1744 | return 1; | |
1745 | ||
1746 | return 0; | |
1747 | } | |
1748 | ||
1749 | /* Update the class of QTY assuming that REG is being tied to it. */ | |
1750 | ||
1751 | static void | |
1752 | update_qty_class (qty, reg) | |
1753 | int qty; | |
1754 | int reg; | |
1755 | { | |
1756 | enum reg_class rclass = reg_preferred_class (reg); | |
1757 | if (reg_class_subset_p (rclass, qty_min_class[qty])) | |
1758 | qty_min_class[qty] = rclass; | |
e4600702 RK |
1759 | |
1760 | rclass = reg_alternate_class (reg); | |
1761 | if (reg_class_subset_p (rclass, qty_alternate_class[qty])) | |
1762 | qty_alternate_class[qty] = rclass; | |
2bbd3819 RS |
1763 | } |
1764 | \f | |
1765 | /* Handle something which alters the value of an rtx REG. | |
1766 | ||
1767 | REG is whatever is set or clobbered. SETTER is the rtx that | |
1768 | is modifying the register. | |
1769 | ||
1770 | If it is not really a register, we do nothing. | |
1771 | The file-global variables `this_insn' and `this_insn_number' | |
1772 | carry info from `block_alloc'. */ | |
1773 | ||
1774 | static void | |
1775 | reg_is_set (reg, setter) | |
1776 | rtx reg; | |
1777 | rtx setter; | |
1778 | { | |
1779 | /* Note that note_stores will only pass us a SUBREG if it is a SUBREG of | |
1780 | a hard register. These may actually not exist any more. */ | |
1781 | ||
1782 | if (GET_CODE (reg) != SUBREG | |
1783 | && GET_CODE (reg) != REG) | |
1784 | return; | |
1785 | ||
1786 | /* Mark this register as being born. If it is used in a CLOBBER, mark | |
1787 | it as being born halfway between the previous insn and this insn so that | |
1788 | it conflicts with our inputs but not the outputs of the previous insn. */ | |
1789 | ||
1790 | reg_is_born (reg, 2 * this_insn_number - (GET_CODE (setter) == CLOBBER)); | |
1791 | } | |
1792 | \f | |
1793 | /* Handle beginning of the life of register REG. | |
1794 | BIRTH is the index at which this is happening. */ | |
1795 | ||
1796 | static void | |
1797 | reg_is_born (reg, birth) | |
1798 | rtx reg; | |
1799 | int birth; | |
1800 | { | |
1801 | register int regno; | |
1802 | ||
1803 | if (GET_CODE (reg) == SUBREG) | |
1804 | regno = REGNO (SUBREG_REG (reg)) + SUBREG_WORD (reg); | |
1805 | else | |
1806 | regno = REGNO (reg); | |
1807 | ||
1808 | if (regno < FIRST_PSEUDO_REGISTER) | |
1809 | { | |
1810 | mark_life (regno, GET_MODE (reg), 1); | |
1811 | ||
1812 | /* If the register was to have been born earlier that the present | |
1813 | insn, mark it as live where it is actually born. */ | |
1814 | if (birth < 2 * this_insn_number) | |
1815 | post_mark_life (regno, GET_MODE (reg), 1, birth, 2 * this_insn_number); | |
1816 | } | |
1817 | else | |
1818 | { | |
1819 | if (reg_qty[regno] == -2) | |
1820 | alloc_qty (regno, GET_MODE (reg), PSEUDO_REGNO_SIZE (regno), birth); | |
1821 | ||
1822 | /* If this register has a quantity number, show that it isn't dead. */ | |
1823 | if (reg_qty[regno] >= 0) | |
1824 | qty_death[reg_qty[regno]] = -1; | |
1825 | } | |
1826 | } | |
1827 | ||
1828 | /* Record the death of REG in the current insn. If OUTPUT_P is non-zero, | |
1829 | REG is an output that is dying (i.e., it is never used), otherwise it | |
333e0f7d RS |
1830 | is an input (the normal case). |
1831 | If OUTPUT_P is 1, then we extend the life past the end of this insn. */ | |
2bbd3819 RS |
1832 | |
1833 | static void | |
1834 | wipe_dead_reg (reg, output_p) | |
1835 | register rtx reg; | |
1836 | int output_p; | |
1837 | { | |
1838 | register int regno = REGNO (reg); | |
1839 | ||
333e0f7d RS |
1840 | /* If this insn has multiple results, |
1841 | and the dead reg is used in one of the results, | |
1842 | extend its life to after this insn, | |
1843 | so it won't get allocated together with any other result of this insn. */ | |
1844 | if (GET_CODE (PATTERN (this_insn)) == PARALLEL | |
1845 | && !single_set (this_insn)) | |
1846 | { | |
1847 | int i; | |
1848 | for (i = XVECLEN (PATTERN (this_insn), 0) - 1; i >= 0; i--) | |
1849 | { | |
1850 | rtx set = XVECEXP (PATTERN (this_insn), 0, i); | |
1851 | if (GET_CODE (set) == SET | |
1852 | && GET_CODE (SET_DEST (set)) != REG | |
1853 | && !rtx_equal_p (reg, SET_DEST (set)) | |
1854 | && reg_overlap_mentioned_p (reg, SET_DEST (set))) | |
1855 | output_p = 1; | |
1856 | } | |
1857 | } | |
1858 | ||
2bbd3819 RS |
1859 | if (regno < FIRST_PSEUDO_REGISTER) |
1860 | { | |
1861 | mark_life (regno, GET_MODE (reg), 0); | |
1862 | ||
1863 | /* If a hard register is dying as an output, mark it as in use at | |
1864 | the beginning of this insn (the above statement would cause this | |
1865 | not to happen). */ | |
1866 | if (output_p) | |
1867 | post_mark_life (regno, GET_MODE (reg), 1, | |
1868 | 2 * this_insn_number, 2 * this_insn_number+ 1); | |
1869 | } | |
1870 | ||
1871 | else if (reg_qty[regno] >= 0) | |
1872 | qty_death[reg_qty[regno]] = 2 * this_insn_number + output_p; | |
1873 | } | |
1874 | \f | |
1875 | /* Find a block of SIZE words of hard regs in reg_class CLASS | |
1876 | that can hold something of machine-mode MODE | |
1877 | (but actually we test only the first of the block for holding MODE) | |
1878 | and still free between insn BORN_INDEX and insn DEAD_INDEX, | |
1879 | and return the number of the first of them. | |
1880 | Return -1 if such a block cannot be found. | |
1881 | If QTY crosses calls, insist on a register preserved by calls, | |
1882 | unless ACCEPT_CALL_CLOBBERED is nonzero. | |
1883 | ||
1884 | If JUST_TRY_SUGGESTED is non-zero, only try to see if the suggested | |
1885 | register is available. If not, return -1. */ | |
1886 | ||
1887 | static int | |
1888 | find_free_reg (class, mode, qty, accept_call_clobbered, just_try_suggested, | |
1889 | born_index, dead_index) | |
1890 | enum reg_class class; | |
1891 | enum machine_mode mode; | |
1892 | int accept_call_clobbered; | |
1893 | int just_try_suggested; | |
1894 | int qty; | |
1895 | int born_index, dead_index; | |
1896 | { | |
1897 | register int i, ins; | |
1898 | #ifdef HARD_REG_SET | |
1899 | register /* Declare it register if it's a scalar. */ | |
1900 | #endif | |
1901 | HARD_REG_SET used, first_used; | |
1902 | #ifdef ELIMINABLE_REGS | |
1903 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; | |
1904 | #endif | |
1905 | ||
1906 | /* Validate our parameters. */ | |
1907 | if (born_index < 0 || born_index > dead_index) | |
1908 | abort (); | |
1909 | ||
1910 | /* Don't let a pseudo live in a reg across a function call | |
1911 | if we might get a nonlocal goto. */ | |
1912 | if (current_function_has_nonlocal_label | |
1913 | && qty_n_calls_crossed[qty] > 0) | |
1914 | return -1; | |
1915 | ||
1916 | if (accept_call_clobbered) | |
1917 | COPY_HARD_REG_SET (used, call_fixed_reg_set); | |
1918 | else if (qty_n_calls_crossed[qty] == 0) | |
1919 | COPY_HARD_REG_SET (used, fixed_reg_set); | |
1920 | else | |
1921 | COPY_HARD_REG_SET (used, call_used_reg_set); | |
1922 | ||
1923 | for (ins = born_index; ins < dead_index; ins++) | |
1924 | IOR_HARD_REG_SET (used, regs_live_at[ins]); | |
1925 | ||
1926 | IOR_COMPL_HARD_REG_SET (used, reg_class_contents[(int) class]); | |
1927 | ||
1928 | /* Don't use the frame pointer reg in local-alloc even if | |
1929 | we may omit the frame pointer, because if we do that and then we | |
1930 | need a frame pointer, reload won't know how to move the pseudo | |
1931 | to another hard reg. It can move only regs made by global-alloc. | |
1932 | ||
1933 | This is true of any register that can be eliminated. */ | |
1934 | #ifdef ELIMINABLE_REGS | |
1935 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) | |
1936 | SET_HARD_REG_BIT (used, eliminables[i].from); | |
1937 | #else | |
1938 | SET_HARD_REG_BIT (used, FRAME_POINTER_REGNUM); | |
1939 | #endif | |
1940 | ||
1941 | /* Normally, the registers that can be used for the first register in | |
1942 | a multi-register quantity are the same as those that can be used for | |
1943 | subsequent registers. However, if just trying suggested registers, | |
1944 | restrict our consideration to them. If there are copy-suggested | |
1945 | register, try them. Otherwise, try the arithmetic-suggested | |
1946 | registers. */ | |
1947 | COPY_HARD_REG_SET (first_used, used); | |
1948 | ||
1949 | if (just_try_suggested) | |
1950 | { | |
1951 | if (qty_phys_has_copy_sugg[qty]) | |
1952 | IOR_COMPL_HARD_REG_SET (first_used, qty_phys_copy_sugg[qty]); | |
1953 | else | |
1954 | IOR_COMPL_HARD_REG_SET (first_used, qty_phys_sugg[qty]); | |
1955 | } | |
1956 | ||
1957 | /* If all registers are excluded, we can't do anything. */ | |
1958 | GO_IF_HARD_REG_SUBSET (reg_class_contents[(int) ALL_REGS], first_used, fail); | |
1959 | ||
1960 | /* If at least one would be suitable, test each hard reg. */ | |
1961 | ||
1962 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
1963 | { | |
1964 | #ifdef REG_ALLOC_ORDER | |
1965 | int regno = reg_alloc_order[i]; | |
1966 | #else | |
1967 | int regno = i; | |
1968 | #endif | |
1969 | if (! TEST_HARD_REG_BIT (first_used, regno) | |
1970 | && HARD_REGNO_MODE_OK (regno, mode)) | |
1971 | { | |
1972 | register int j; | |
1973 | register int size1 = HARD_REGNO_NREGS (regno, mode); | |
1974 | for (j = 1; j < size1 && ! TEST_HARD_REG_BIT (used, regno + j); j++); | |
1975 | if (j == size1) | |
1976 | { | |
1977 | /* Mark that this register is in use between its birth and death | |
1978 | insns. */ | |
1979 | post_mark_life (regno, mode, 1, born_index, dead_index); | |
1980 | return regno; | |
1981 | } | |
1982 | #ifndef REG_ALLOC_ORDER | |
1983 | i += j; /* Skip starting points we know will lose */ | |
1984 | #endif | |
1985 | } | |
1986 | } | |
1987 | ||
1988 | fail: | |
1989 | ||
1990 | /* If we are just trying suggested register, we have just tried copy- | |
1991 | suggested registers, and there are arithmetic-suggested registers, | |
1992 | try them. */ | |
1993 | ||
1994 | /* If it would be profitable to allocate a call-clobbered register | |
1995 | and save and restore it around calls, do that. */ | |
1996 | if (just_try_suggested && qty_phys_has_copy_sugg[qty] | |
1997 | && qty_phys_has_sugg[qty]) | |
1998 | { | |
1999 | /* Don't try the copy-suggested regs again. */ | |
2000 | qty_phys_has_copy_sugg[qty] = 0; | |
2001 | return find_free_reg (class, mode, qty, accept_call_clobbered, 1, | |
2002 | born_index, dead_index); | |
2003 | } | |
2004 | ||
e19f5192 RK |
2005 | /* We need not check to see if the current function has nonlocal |
2006 | labels because we don't put any pseudos that are live over calls in | |
2007 | registers in that case. */ | |
2008 | ||
2bbd3819 RS |
2009 | if (! accept_call_clobbered |
2010 | && flag_caller_saves | |
2011 | && ! just_try_suggested | |
2012 | && qty_n_calls_crossed[qty] != 0 | |
2013 | && CALLER_SAVE_PROFITABLE (qty_n_refs[qty], qty_n_calls_crossed[qty])) | |
2014 | { | |
2015 | i = find_free_reg (class, mode, qty, 1, 0, born_index, dead_index); | |
2016 | if (i >= 0) | |
2017 | caller_save_needed = 1; | |
2018 | return i; | |
2019 | } | |
2020 | return -1; | |
2021 | } | |
2022 | \f | |
2023 | /* Mark that REGNO with machine-mode MODE is live starting from the current | |
2024 | insn (if LIFE is non-zero) or dead starting at the current insn (if LIFE | |
2025 | is zero). */ | |
2026 | ||
2027 | static void | |
2028 | mark_life (regno, mode, life) | |
2029 | register int regno; | |
2030 | enum machine_mode mode; | |
2031 | int life; | |
2032 | { | |
2033 | register int j = HARD_REGNO_NREGS (regno, mode); | |
2034 | if (life) | |
2035 | while (--j >= 0) | |
2036 | SET_HARD_REG_BIT (regs_live, regno + j); | |
2037 | else | |
2038 | while (--j >= 0) | |
2039 | CLEAR_HARD_REG_BIT (regs_live, regno + j); | |
2040 | } | |
2041 | ||
2042 | /* Mark register number REGNO (with machine-mode MODE) as live (if LIFE | |
2043 | is non-zero) or dead (if LIFE is zero) from insn number BIRTH (inclusive) | |
2044 | to insn number DEATH (exclusive). */ | |
2045 | ||
2046 | static void | |
2047 | post_mark_life (regno, mode, life, birth, death) | |
2048 | register int regno, life, birth; | |
2049 | enum machine_mode mode; | |
2050 | int death; | |
2051 | { | |
2052 | register int j = HARD_REGNO_NREGS (regno, mode); | |
2053 | #ifdef HARD_REG_SET | |
2054 | register /* Declare it register if it's a scalar. */ | |
2055 | #endif | |
2056 | HARD_REG_SET this_reg; | |
2057 | ||
2058 | CLEAR_HARD_REG_SET (this_reg); | |
2059 | while (--j >= 0) | |
2060 | SET_HARD_REG_BIT (this_reg, regno + j); | |
2061 | ||
2062 | if (life) | |
2063 | while (birth < death) | |
2064 | { | |
2065 | IOR_HARD_REG_SET (regs_live_at[birth], this_reg); | |
2066 | birth++; | |
2067 | } | |
2068 | else | |
2069 | while (birth < death) | |
2070 | { | |
2071 | AND_COMPL_HARD_REG_SET (regs_live_at[birth], this_reg); | |
2072 | birth++; | |
2073 | } | |
2074 | } | |
2075 | \f | |
2076 | /* INSN is the CLOBBER insn that starts a REG_NO_NOCONFLICT block, R0 | |
2077 | is the register being clobbered, and R1 is a register being used in | |
2078 | the equivalent expression. | |
2079 | ||
2080 | If R1 dies in the block and has a REG_NO_CONFLICT note on every insn | |
2081 | in which it is used, return 1. | |
2082 | ||
2083 | Otherwise, return 0. */ | |
2084 | ||
2085 | static int | |
2086 | no_conflict_p (insn, r0, r1) | |
2087 | rtx insn, r0, r1; | |
2088 | { | |
2089 | int ok = 0; | |
b1ec3c92 | 2090 | rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX); |
2bbd3819 RS |
2091 | rtx p, last; |
2092 | ||
2093 | /* If R1 is a hard register, return 0 since we handle this case | |
2094 | when we scan the insns that actually use it. */ | |
2095 | ||
2096 | if (note == 0 | |
2097 | || (GET_CODE (r1) == REG && REGNO (r1) < FIRST_PSEUDO_REGISTER) | |
2098 | || (GET_CODE (r1) == SUBREG && GET_CODE (SUBREG_REG (r1)) == REG | |
2099 | && REGNO (SUBREG_REG (r1)) < FIRST_PSEUDO_REGISTER)) | |
2100 | return 0; | |
2101 | ||
2102 | last = XEXP (note, 0); | |
2103 | ||
2104 | for (p = NEXT_INSN (insn); p && p != last; p = NEXT_INSN (p)) | |
2105 | if (GET_RTX_CLASS (GET_CODE (p)) == 'i') | |
2106 | { | |
2107 | if (find_reg_note (p, REG_DEAD, r1)) | |
2108 | ok = 1; | |
2109 | ||
2110 | if (reg_mentioned_p (r1, PATTERN (p)) | |
2111 | && ! find_reg_note (p, REG_NO_CONFLICT, r1)) | |
2112 | return 0; | |
2113 | } | |
2114 | ||
2115 | return ok; | |
2116 | } | |
2117 | \f | |
7fe4336e RK |
2118 | #ifdef REGISTER_CONSTRAINTS |
2119 | ||
2bbd3819 RS |
2120 | /* Return 1 if the constraint string P indicates that the a the operand |
2121 | must be equal to operand 0 and that no register is acceptable. */ | |
2122 | ||
2123 | static int | |
2124 | requires_inout_p (p) | |
2125 | char *p; | |
2126 | { | |
2127 | char c; | |
2128 | int found_zero = 0; | |
2129 | ||
2130 | while (c = *p++) | |
2131 | switch (c) | |
2132 | { | |
2133 | case '0': | |
2134 | found_zero = 1; | |
2135 | break; | |
2136 | ||
2137 | case '=': case '+': case '?': | |
2138 | case '#': case '&': case '!': | |
2139 | case '*': case '%': case ',': | |
2140 | case '1': case '2': case '3': case '4': | |
2141 | case 'm': case '<': case '>': case 'V': case 'o': | |
2142 | case 'E': case 'F': case 'G': case 'H': | |
2143 | case 's': case 'i': case 'n': | |
2144 | case 'I': case 'J': case 'K': case 'L': | |
2145 | case 'M': case 'N': case 'O': case 'P': | |
2146 | #ifdef EXTRA_CONSTRAINT | |
2147 | case 'Q': case 'R': case 'S': case 'T': case 'U': | |
2148 | #endif | |
2149 | case 'X': | |
2150 | /* These don't say anything we care about. */ | |
2151 | break; | |
2152 | ||
2153 | case 'p': | |
2154 | case 'g': case 'r': | |
2155 | default: | |
2156 | /* These mean a register is allowed. Fail if so. */ | |
2157 | return 0; | |
2158 | } | |
2159 | ||
2160 | return found_zero; | |
2161 | } | |
7fe4336e | 2162 | #endif /* REGISTER_CONSTRAINTS */ |
2bbd3819 RS |
2163 | \f |
2164 | void | |
2165 | dump_local_alloc (file) | |
2166 | FILE *file; | |
2167 | { | |
2168 | register int i; | |
2169 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
2170 | if (reg_renumber[i] != -1) | |
2171 | fprintf (file, ";; Register %d in %d.\n", i, reg_renumber[i]); | |
2172 | } |