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d7429b6a | 1 | /* Data flow analysis for GNU compiler. |
081f5e7e | 2 | Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc. |
d7429b6a RK |
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 | |
a35311b0 RK |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
19 | Boston, MA 02111-1307, USA. */ | |
d7429b6a RK |
20 | |
21 | ||
22 | /* This file contains the data flow analysis pass of the compiler. | |
23 | It computes data flow information | |
24 | which tells combine_instructions which insns to consider combining | |
25 | and controls register allocation. | |
26 | ||
27 | Additional data flow information that is too bulky to record | |
28 | is generated during the analysis, and is used at that time to | |
29 | create autoincrement and autodecrement addressing. | |
30 | ||
31 | The first step is dividing the function into basic blocks. | |
32 | find_basic_blocks does this. Then life_analysis determines | |
33 | where each register is live and where it is dead. | |
34 | ||
35 | ** find_basic_blocks ** | |
36 | ||
37 | find_basic_blocks divides the current function's rtl | |
38 | into basic blocks. It records the beginnings and ends of the | |
39 | basic blocks in the vectors basic_block_head and basic_block_end, | |
40 | and the number of blocks in n_basic_blocks. | |
41 | ||
42 | find_basic_blocks also finds any unreachable loops | |
43 | and deletes them. | |
44 | ||
45 | ** life_analysis ** | |
46 | ||
47 | life_analysis is called immediately after find_basic_blocks. | |
48 | It uses the basic block information to determine where each | |
49 | hard or pseudo register is live. | |
50 | ||
51 | ** live-register info ** | |
52 | ||
53 | The information about where each register is live is in two parts: | |
54 | the REG_NOTES of insns, and the vector basic_block_live_at_start. | |
55 | ||
56 | basic_block_live_at_start has an element for each basic block, | |
57 | and the element is a bit-vector with a bit for each hard or pseudo | |
58 | register. The bit is 1 if the register is live at the beginning | |
59 | of the basic block. | |
60 | ||
61 | Two types of elements can be added to an insn's REG_NOTES. | |
62 | A REG_DEAD note is added to an insn's REG_NOTES for any register | |
63 | that meets both of two conditions: The value in the register is not | |
64 | needed in subsequent insns and the insn does not replace the value in | |
65 | the register (in the case of multi-word hard registers, the value in | |
66 | each register must be replaced by the insn to avoid a REG_DEAD note). | |
67 | ||
68 | In the vast majority of cases, an object in a REG_DEAD note will be | |
69 | used somewhere in the insn. The (rare) exception to this is if an | |
70 | insn uses a multi-word hard register and only some of the registers are | |
71 | needed in subsequent insns. In that case, REG_DEAD notes will be | |
72 | provided for those hard registers that are not subsequently needed. | |
73 | Partial REG_DEAD notes of this type do not occur when an insn sets | |
74 | only some of the hard registers used in such a multi-word operand; | |
75 | omitting REG_DEAD notes for objects stored in an insn is optional and | |
76 | the desire to do so does not justify the complexity of the partial | |
77 | REG_DEAD notes. | |
78 | ||
79 | REG_UNUSED notes are added for each register that is set by the insn | |
80 | but is unused subsequently (if every register set by the insn is unused | |
81 | and the insn does not reference memory or have some other side-effect, | |
82 | the insn is deleted instead). If only part of a multi-word hard | |
83 | register is used in a subsequent insn, REG_UNUSED notes are made for | |
84 | the parts that will not be used. | |
85 | ||
86 | To determine which registers are live after any insn, one can | |
87 | start from the beginning of the basic block and scan insns, noting | |
88 | which registers are set by each insn and which die there. | |
89 | ||
90 | ** Other actions of life_analysis ** | |
91 | ||
92 | life_analysis sets up the LOG_LINKS fields of insns because the | |
93 | information needed to do so is readily available. | |
94 | ||
95 | life_analysis deletes insns whose only effect is to store a value | |
96 | that is never used. | |
97 | ||
98 | life_analysis notices cases where a reference to a register as | |
99 | a memory address can be combined with a preceding or following | |
100 | incrementation or decrementation of the register. The separate | |
101 | instruction to increment or decrement is deleted and the address | |
102 | is changed to a POST_INC or similar rtx. | |
103 | ||
104 | Each time an incrementing or decrementing address is created, | |
105 | a REG_INC element is added to the insn's REG_NOTES list. | |
106 | ||
107 | life_analysis fills in certain vectors containing information about | |
108 | register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length, | |
109 | reg_n_calls_crosses and reg_basic_block. */ | |
110 | \f | |
d7429b6a | 111 | #include "config.h" |
670ee920 | 112 | #include "system.h" |
d7429b6a RK |
113 | #include "rtl.h" |
114 | #include "basic-block.h" | |
115 | #include "insn-config.h" | |
116 | #include "regs.h" | |
117 | #include "hard-reg-set.h" | |
118 | #include "flags.h" | |
119 | #include "output.h" | |
3d195391 | 120 | #include "except.h" |
d7429b6a RK |
121 | |
122 | #include "obstack.h" | |
123 | #define obstack_chunk_alloc xmalloc | |
124 | #define obstack_chunk_free free | |
125 | ||
7eb136d6 MM |
126 | /* The contents of the current function definition are allocated |
127 | in this obstack, and all are freed at the end of the function. | |
128 | For top-level functions, this is temporary_obstack. | |
129 | Separate obstacks are made for nested functions. */ | |
130 | ||
131 | extern struct obstack *function_obstack; | |
132 | ||
d7429b6a RK |
133 | /* List of labels that must never be deleted. */ |
134 | extern rtx forced_labels; | |
135 | ||
136 | /* Get the basic block number of an insn. | |
137 | This info should not be expected to remain available | |
138 | after the end of life_analysis. */ | |
139 | ||
140 | /* This is the limit of the allocated space in the following two arrays. */ | |
141 | ||
142 | static int max_uid_for_flow; | |
143 | ||
144 | #define BLOCK_NUM(INSN) uid_block_number[INSN_UID (INSN)] | |
145 | ||
146 | /* This is where the BLOCK_NUM values are really stored. | |
147 | This is set up by find_basic_blocks and used there and in life_analysis, | |
148 | and then freed. */ | |
149 | ||
5ece9746 | 150 | int *uid_block_number; |
d7429b6a RK |
151 | |
152 | /* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */ | |
153 | ||
154 | #define INSN_VOLATILE(INSN) uid_volatile[INSN_UID (INSN)] | |
155 | static char *uid_volatile; | |
156 | ||
157 | /* Number of basic blocks in the current function. */ | |
158 | ||
159 | int n_basic_blocks; | |
160 | ||
161 | /* Maximum register number used in this function, plus one. */ | |
162 | ||
163 | int max_regno; | |
164 | ||
0f41302f MS |
165 | /* Maximum number of SCRATCH rtx's used in any basic block of this |
166 | function. */ | |
d7429b6a RK |
167 | |
168 | int max_scratch; | |
169 | ||
170 | /* Number of SCRATCH rtx's in the current block. */ | |
171 | ||
172 | static int num_scratch; | |
173 | ||
b1f21e0a | 174 | /* Indexed by n, giving various register information */ |
d7429b6a | 175 | |
b1f21e0a | 176 | reg_info *reg_n_info; |
d7429b6a | 177 | |
a494747c MM |
178 | /* Size of the reg_n_info table. */ |
179 | ||
180 | unsigned int reg_n_max; | |
181 | ||
d7429b6a RK |
182 | /* Element N is the next insn that uses (hard or pseudo) register number N |
183 | within the current basic block; or zero, if there is no such insn. | |
184 | This is valid only during the final backward scan in propagate_block. */ | |
185 | ||
186 | static rtx *reg_next_use; | |
187 | ||
188 | /* Size of a regset for the current function, | |
189 | in (1) bytes and (2) elements. */ | |
190 | ||
191 | int regset_bytes; | |
192 | int regset_size; | |
193 | ||
194 | /* Element N is first insn in basic block N. | |
195 | This info lasts until we finish compiling the function. */ | |
196 | ||
197 | rtx *basic_block_head; | |
198 | ||
199 | /* Element N is last insn in basic block N. | |
200 | This info lasts until we finish compiling the function. */ | |
201 | ||
202 | rtx *basic_block_end; | |
203 | ||
4d1d8045 BS |
204 | /* Element N indicates whether basic block N can be reached through a |
205 | computed jump. */ | |
206 | ||
207 | char *basic_block_computed_jump_target; | |
208 | ||
d7429b6a RK |
209 | /* Element N is a regset describing the registers live |
210 | at the start of basic block N. | |
211 | This info lasts until we finish compiling the function. */ | |
212 | ||
213 | regset *basic_block_live_at_start; | |
214 | ||
215 | /* Regset of regs live when calls to `setjmp'-like functions happen. */ | |
216 | ||
217 | regset regs_live_at_setjmp; | |
218 | ||
219 | /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers | |
220 | that have to go in the same hard reg. | |
221 | The first two regs in the list are a pair, and the next two | |
222 | are another pair, etc. */ | |
223 | rtx regs_may_share; | |
224 | ||
225 | /* Element N is nonzero if control can drop into basic block N | |
226 | from the preceding basic block. Freed after life_analysis. */ | |
227 | ||
228 | static char *basic_block_drops_in; | |
229 | ||
230 | /* Element N is depth within loops of the last insn in basic block number N. | |
231 | Freed after life_analysis. */ | |
232 | ||
233 | static short *basic_block_loop_depth; | |
234 | ||
235 | /* Element N nonzero if basic block N can actually be reached. | |
236 | Vector exists only during find_basic_blocks. */ | |
237 | ||
238 | static char *block_live_static; | |
239 | ||
240 | /* Depth within loops of basic block being scanned for lifetime analysis, | |
241 | plus one. This is the weight attached to references to registers. */ | |
242 | ||
243 | static int loop_depth; | |
244 | ||
245 | /* During propagate_block, this is non-zero if the value of CC0 is live. */ | |
246 | ||
247 | static int cc0_live; | |
248 | ||
249 | /* During propagate_block, this contains the last MEM stored into. It | |
250 | is used to eliminate consecutive stores to the same location. */ | |
251 | ||
252 | static rtx last_mem_set; | |
253 | ||
254 | /* Set of registers that may be eliminable. These are handled specially | |
255 | in updating regs_ever_live. */ | |
256 | ||
257 | static HARD_REG_SET elim_reg_set; | |
258 | ||
259 | /* Forward declarations */ | |
5ece9746 | 260 | static void find_basic_blocks_1 PROTO((rtx, rtx, int)); |
e658434c | 261 | static void mark_label_ref PROTO((rtx, rtx, int)); |
5ece9746 | 262 | static void life_analysis_1 PROTO((rtx, int)); |
e658434c | 263 | void allocate_for_life_analysis PROTO((void)); |
67f0e213 | 264 | void init_regset_vector PROTO((regset *, int, struct obstack *)); |
e658434c RK |
265 | static void propagate_block PROTO((regset, rtx, rtx, int, |
266 | regset, int)); | |
8329b5ec | 267 | static rtx flow_delete_insn PROTO((rtx)); |
e658434c RK |
268 | static int insn_dead_p PROTO((rtx, regset, int)); |
269 | static int libcall_dead_p PROTO((rtx, regset, rtx, rtx)); | |
270 | static void mark_set_regs PROTO((regset, regset, rtx, | |
271 | rtx, regset)); | |
272 | static void mark_set_1 PROTO((regset, regset, rtx, | |
273 | rtx, regset)); | |
1d300e19 | 274 | #ifdef AUTO_INC_DEC |
e658434c | 275 | static void find_auto_inc PROTO((regset, rtx, rtx)); |
e658434c RK |
276 | static int try_pre_increment_1 PROTO((rtx)); |
277 | static int try_pre_increment PROTO((rtx, rtx, HOST_WIDE_INT)); | |
1d300e19 KG |
278 | #endif |
279 | static void mark_used_regs PROTO((regset, regset, rtx, int, rtx)); | |
e658434c | 280 | void dump_flow_info PROTO((FILE *)); |
5ece9746 JL |
281 | static void add_pred_succ PROTO ((int, int, int_list_ptr *, |
282 | int_list_ptr *, int *, int *)); | |
283 | static int_list_ptr alloc_int_list_node PROTO ((int_list_block **)); | |
284 | static int_list_ptr add_int_list_node PROTO ((int_list_block **, | |
285 | int_list **, int)); | |
d7429b6a | 286 | \f |
5ece9746 | 287 | /* Find basic blocks of the current function. |
d7429b6a | 288 | F is the first insn of the function and NREGS the number of register numbers |
5ece9746 JL |
289 | in use. |
290 | LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to | |
291 | be reachable. This turns on a kludge that causes the control flow | |
292 | information to be inaccurate and not suitable for passes like GCSE. */ | |
d7429b6a RK |
293 | |
294 | void | |
5ece9746 | 295 | find_basic_blocks (f, nregs, file, live_reachable_p) |
d7429b6a RK |
296 | rtx f; |
297 | int nregs; | |
298 | FILE *file; | |
5ece9746 | 299 | int live_reachable_p; |
d7429b6a RK |
300 | { |
301 | register rtx insn; | |
302 | register int i; | |
d7e4fe8b | 303 | rtx nonlocal_label_list = nonlocal_label_rtx_list (); |
2c3a56ad | 304 | int in_libcall_block = 0; |
d7429b6a | 305 | |
d7429b6a RK |
306 | /* Count the basic blocks. Also find maximum insn uid value used. */ |
307 | ||
308 | { | |
309 | register RTX_CODE prev_code = JUMP_INSN; | |
310 | register RTX_CODE code; | |
74d7ab55 | 311 | int eh_region = 0; |
d7429b6a RK |
312 | |
313 | max_uid_for_flow = 0; | |
314 | ||
315 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) | |
316 | { | |
2c3a56ad JL |
317 | |
318 | /* Track when we are inside in LIBCALL block. */ | |
319 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
320 | && find_reg_note (insn, REG_LIBCALL, NULL_RTX)) | |
321 | in_libcall_block = 1; | |
322 | ||
d7429b6a RK |
323 | code = GET_CODE (insn); |
324 | if (INSN_UID (insn) > max_uid_for_flow) | |
325 | max_uid_for_flow = INSN_UID (insn); | |
326 | if (code == CODE_LABEL | |
d7e4fe8b RS |
327 | || (GET_RTX_CLASS (code) == 'i' |
328 | && (prev_code == JUMP_INSN | |
329 | || (prev_code == CALL_INSN | |
9b8d9d6b | 330 | && (nonlocal_label_list != 0 || eh_region) |
2c3a56ad | 331 | && ! in_libcall_block) |
d7e4fe8b | 332 | || prev_code == BARRIER))) |
d7429b6a | 333 | i++; |
8cfe18d6 | 334 | |
2dd4cace | 335 | if (code == CALL_INSN && find_reg_note (insn, REG_RETVAL, NULL_RTX)) |
8cfe18d6 RK |
336 | code = INSN; |
337 | ||
6b67ec08 | 338 | if (code != NOTE) |
d7429b6a | 339 | prev_code = code; |
74d7ab55 JM |
340 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) |
341 | ++eh_region; | |
342 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) | |
343 | --eh_region; | |
2c3a56ad JL |
344 | |
345 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
346 | && find_reg_note (insn, REG_RETVAL, NULL_RTX)) | |
347 | in_libcall_block = 0; | |
d7429b6a RK |
348 | } |
349 | } | |
350 | ||
5ece9746 JL |
351 | n_basic_blocks = i; |
352 | ||
d7429b6a | 353 | #ifdef AUTO_INC_DEC |
5ece9746 JL |
354 | /* Leave space for insns life_analysis makes in some cases for auto-inc. |
355 | These cases are rare, so we don't need too much space. */ | |
d7429b6a RK |
356 | max_uid_for_flow += max_uid_for_flow / 10; |
357 | #endif | |
358 | ||
359 | /* Allocate some tables that last till end of compiling this function | |
360 | and some needed only in find_basic_blocks and life_analysis. */ | |
361 | ||
5ece9746 JL |
362 | basic_block_head = (rtx *) xmalloc (n_basic_blocks * sizeof (rtx)); |
363 | basic_block_end = (rtx *) xmalloc (n_basic_blocks * sizeof (rtx)); | |
364 | basic_block_drops_in = (char *) xmalloc (n_basic_blocks); | |
4d1d8045 | 365 | basic_block_computed_jump_target = (char *) oballoc (n_basic_blocks); |
5ece9746 | 366 | basic_block_loop_depth = (short *) xmalloc (n_basic_blocks * sizeof (short)); |
d7429b6a | 367 | uid_block_number |
5ece9746 JL |
368 | = (int *) xmalloc ((max_uid_for_flow + 1) * sizeof (int)); |
369 | uid_volatile = (char *) xmalloc (max_uid_for_flow + 1); | |
d7429b6a RK |
370 | bzero (uid_volatile, max_uid_for_flow + 1); |
371 | ||
5ece9746 | 372 | find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p); |
d7429b6a | 373 | } |
5ece9746 | 374 | |
d7429b6a RK |
375 | /* Find all basic blocks of the function whose first insn is F. |
376 | Store the correct data in the tables that describe the basic blocks, | |
377 | set up the chains of references for each CODE_LABEL, and | |
d7e4fe8b RS |
378 | delete any entire basic blocks that cannot be reached. |
379 | ||
5ece9746 JL |
380 | NONLOCAL_LABEL_LIST is a list of non-local labels in the function. |
381 | Blocks that are otherwise unreachable may be reachable with a non-local | |
382 | goto. | |
383 | LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to | |
384 | be reachable. This turns on a kludge that causes the control flow | |
385 | information to be inaccurate and not suitable for passes like GCSE. */ | |
d7429b6a RK |
386 | |
387 | static void | |
5ece9746 | 388 | find_basic_blocks_1 (f, nonlocal_label_list, live_reachable_p) |
d7e4fe8b | 389 | rtx f, nonlocal_label_list; |
5ece9746 | 390 | int live_reachable_p; |
d7429b6a RK |
391 | { |
392 | register rtx insn; | |
393 | register int i; | |
394 | register char *block_live = (char *) alloca (n_basic_blocks); | |
395 | register char *block_marked = (char *) alloca (n_basic_blocks); | |
2ec1535d JL |
396 | /* An array of CODE_LABELs, indexed by UID for the start of the active |
397 | EH handler for each insn in F. */ | |
9a0d1e1b AM |
398 | int *active_eh_region; |
399 | int *nested_eh_region; | |
d7429b6a RK |
400 | /* List of label_refs to all labels whose addresses are taken |
401 | and used as data. */ | |
8329b5ec | 402 | rtx label_value_list; |
2ec1535d | 403 | rtx x, note, eh_note; |
e658434c | 404 | enum rtx_code prev_code, code; |
8329b5ec | 405 | int depth, pass; |
2c3a56ad | 406 | int in_libcall_block = 0; |
d7429b6a | 407 | |
8329b5ec | 408 | pass = 1; |
9a0d1e1b AM |
409 | active_eh_region = (int *) alloca ((max_uid_for_flow + 1) * sizeof (int)); |
410 | nested_eh_region = (int *) alloca ((max_label_num () + 1) * sizeof (int)); | |
8329b5ec DE |
411 | restart: |
412 | ||
413 | label_value_list = 0; | |
d7429b6a RK |
414 | block_live_static = block_live; |
415 | bzero (block_live, n_basic_blocks); | |
416 | bzero (block_marked, n_basic_blocks); | |
4d1d8045 | 417 | bzero (basic_block_computed_jump_target, n_basic_blocks); |
9a0d1e1b AM |
418 | bzero ((char *) active_eh_region, (max_uid_for_flow + 1) * sizeof (int)); |
419 | bzero ((char *) nested_eh_region, (max_label_num () + 1) * sizeof (int)); | |
4d1d8045 | 420 | current_function_has_computed_jump = 0; |
d7429b6a RK |
421 | |
422 | /* Initialize with just block 0 reachable and no blocks marked. */ | |
423 | if (n_basic_blocks > 0) | |
424 | block_live[0] = 1; | |
425 | ||
e658434c RK |
426 | /* Initialize the ref chain of each label to 0. Record where all the |
427 | blocks start and end and their depth in loops. For each insn, record | |
428 | the block it is in. Also mark as reachable any blocks headed by labels | |
429 | that must not be deleted. */ | |
d7429b6a | 430 | |
2ec1535d | 431 | for (eh_note = NULL_RTX, insn = f, i = -1, prev_code = JUMP_INSN, depth = 1; |
e658434c RK |
432 | insn; insn = NEXT_INSN (insn)) |
433 | { | |
2c3a56ad JL |
434 | |
435 | /* Track when we are inside in LIBCALL block. */ | |
436 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
437 | && find_reg_note (insn, REG_LIBCALL, NULL_RTX)) | |
438 | in_libcall_block = 1; | |
439 | ||
e658434c RK |
440 | code = GET_CODE (insn); |
441 | if (code == NOTE) | |
442 | { | |
443 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
444 | depth++; | |
445 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
446 | depth--; | |
447 | } | |
d7429b6a | 448 | |
e658434c RK |
449 | /* A basic block starts at label, or after something that can jump. */ |
450 | else if (code == CODE_LABEL | |
451 | || (GET_RTX_CLASS (code) == 'i' | |
452 | && (prev_code == JUMP_INSN | |
453 | || (prev_code == CALL_INSN | |
74d7ab55 | 454 | && (nonlocal_label_list != 0 || eh_note) |
2c3a56ad | 455 | && ! in_libcall_block) |
e658434c RK |
456 | || prev_code == BARRIER))) |
457 | { | |
458 | basic_block_head[++i] = insn; | |
459 | basic_block_end[i] = insn; | |
460 | basic_block_loop_depth[i] = depth; | |
461 | ||
462 | if (code == CODE_LABEL) | |
463 | { | |
d7429b6a RK |
464 | LABEL_REFS (insn) = insn; |
465 | /* Any label that cannot be deleted | |
466 | is considered to start a reachable block. */ | |
467 | if (LABEL_PRESERVE_P (insn)) | |
468 | block_live[i] = 1; | |
469 | } | |
e658434c | 470 | } |
d7429b6a | 471 | |
e658434c RK |
472 | else if (GET_RTX_CLASS (code) == 'i') |
473 | { | |
474 | basic_block_end[i] = insn; | |
475 | basic_block_loop_depth[i] = depth; | |
42fa3cfb | 476 | } |
e658434c | 477 | |
42fa3cfb JW |
478 | if (GET_RTX_CLASS (code) == 'i') |
479 | { | |
e658434c RK |
480 | /* Make a list of all labels referred to other than by jumps. */ |
481 | for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
482 | if (REG_NOTE_KIND (note) == REG_LABEL) | |
38a448ca RH |
483 | label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0), |
484 | label_value_list); | |
42fa3cfb | 485 | } |
d7429b6a | 486 | |
9a0d1e1b | 487 | /* Keep a lifo list of the currently active exception notes. */ |
2ec1535d JL |
488 | if (GET_CODE (insn) == NOTE) |
489 | { | |
490 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) | |
491 | { | |
9a0d1e1b AM |
492 | if (eh_note) |
493 | nested_eh_region [NOTE_BLOCK_NUMBER (insn)] = | |
494 | NOTE_BLOCK_NUMBER (XEXP (eh_note, 0)); | |
495 | else | |
496 | nested_eh_region [NOTE_BLOCK_NUMBER (insn)] = 0; | |
497 | eh_note = gen_rtx_EXPR_LIST (VOIDmode, | |
498 | insn, eh_note); | |
2ec1535d JL |
499 | } |
500 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) | |
501 | eh_note = XEXP (eh_note, 1); | |
502 | } | |
503 | /* If we encounter a CALL_INSN, note which exception handler it | |
504 | might pass control to. | |
505 | ||
506 | If doing asynchronous exceptions, record the active EH handler | |
507 | for every insn, since most insns can throw. */ | |
508 | else if (eh_note | |
509 | && (asynchronous_exceptions | |
510 | || (GET_CODE (insn) == CALL_INSN | |
2c3a56ad | 511 | && ! in_libcall_block))) |
9a0d1e1b AM |
512 | active_eh_region[INSN_UID (insn)] = |
513 | NOTE_BLOCK_NUMBER (XEXP (eh_note, 0)); | |
e658434c | 514 | BLOCK_NUM (insn) = i; |
d7e4fe8b | 515 | |
6b67ec08 | 516 | if (code != NOTE) |
e658434c | 517 | prev_code = code; |
2c3a56ad JL |
518 | |
519 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
520 | && find_reg_note (insn, REG_RETVAL, NULL_RTX)) | |
521 | in_libcall_block = 0; | |
e658434c RK |
522 | } |
523 | ||
2aec79e2 DE |
524 | /* During the second pass, `n_basic_blocks' is only an upper bound. |
525 | Only perform the sanity check for the first pass, and on the second | |
526 | pass ensure `n_basic_blocks' is set to the correct value. */ | |
527 | if (pass == 1 && i + 1 != n_basic_blocks) | |
e658434c | 528 | abort (); |
2aec79e2 | 529 | n_basic_blocks = i + 1; |
d7429b6a RK |
530 | |
531 | /* Record which basic blocks control can drop in to. */ | |
532 | ||
e658434c RK |
533 | for (i = 0; i < n_basic_blocks; i++) |
534 | { | |
535 | for (insn = PREV_INSN (basic_block_head[i]); | |
536 | insn && GET_CODE (insn) == NOTE; insn = PREV_INSN (insn)) | |
537 | ; | |
538 | ||
539 | basic_block_drops_in[i] = insn && GET_CODE (insn) != BARRIER; | |
540 | } | |
d7429b6a RK |
541 | |
542 | /* Now find which basic blocks can actually be reached | |
543 | and put all jump insns' LABEL_REFS onto the ref-chains | |
544 | of their target labels. */ | |
545 | ||
546 | if (n_basic_blocks > 0) | |
547 | { | |
548 | int something_marked = 1; | |
8329b5ec | 549 | int deleted; |
d7429b6a | 550 | |
d7429b6a RK |
551 | /* Pass over all blocks, marking each block that is reachable |
552 | and has not yet been marked. | |
553 | Keep doing this until, in one pass, no blocks have been marked. | |
554 | Then blocks_live and blocks_marked are identical and correct. | |
555 | In addition, all jumps actually reachable have been marked. */ | |
556 | ||
557 | while (something_marked) | |
558 | { | |
559 | something_marked = 0; | |
560 | for (i = 0; i < n_basic_blocks; i++) | |
561 | if (block_live[i] && !block_marked[i]) | |
562 | { | |
563 | block_marked[i] = 1; | |
564 | something_marked = 1; | |
565 | if (i + 1 < n_basic_blocks && basic_block_drops_in[i + 1]) | |
566 | block_live[i + 1] = 1; | |
567 | insn = basic_block_end[i]; | |
568 | if (GET_CODE (insn) == JUMP_INSN) | |
569 | mark_label_ref (PATTERN (insn), insn, 0); | |
812059fe | 570 | |
2ec1535d JL |
571 | /* If we have any forced labels, mark them as potentially |
572 | reachable from this block. */ | |
573 | for (x = forced_labels; x; x = XEXP (x, 1)) | |
574 | if (! LABEL_REF_NONLOCAL_P (x)) | |
38a448ca | 575 | mark_label_ref (gen_rtx_LABEL_REF (VOIDmode, XEXP (x, 0)), |
2ec1535d JL |
576 | insn, 0); |
577 | ||
578 | /* Now scan the insns for this block, we may need to make | |
579 | edges for some of them to various non-obvious locations | |
580 | (exception handlers, nonlocal labels, etc). */ | |
581 | for (insn = basic_block_head[i]; | |
582 | insn != NEXT_INSN (basic_block_end[i]); | |
583 | insn = NEXT_INSN (insn)) | |
584 | { | |
585 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') | |
586 | { | |
587 | ||
8930b063 JL |
588 | /* References to labels in non-jumping insns have |
589 | REG_LABEL notes attached to them. | |
590 | ||
591 | This can happen for computed gotos; we don't care | |
592 | about them here since the values are also on the | |
593 | label_value_list and will be marked live if we find | |
594 | a live computed goto. | |
595 | ||
596 | This can also happen when we take the address of | |
597 | a label to pass as an argument to __throw. Note | |
598 | throw only uses the value to determine what handler | |
599 | should be called -- ie the label is not used as | |
600 | a jump target, it just marks regions in the code. | |
601 | ||
602 | In theory we should be able to ignore the REG_LABEL | |
603 | notes, but we have to make sure that the label and | |
604 | associated insns aren't marked dead, so we make | |
605 | the block in question live and create an edge from | |
606 | this insn to the label. This is not strictly | |
e701eb4d | 607 | correct, but it is close enough for now. */ |
2ec1535d JL |
608 | for (note = REG_NOTES (insn); |
609 | note; | |
610 | note = XEXP (note, 1)) | |
611 | { | |
812059fe MS |
612 | if (REG_NOTE_KIND (note) == REG_LABEL) |
613 | { | |
614 | x = XEXP (note, 0); | |
615 | block_live[BLOCK_NUM (x)] = 1; | |
38a448ca | 616 | mark_label_ref (gen_rtx_LABEL_REF (VOIDmode, x), |
8930b063 | 617 | insn, 0); |
2ec1535d JL |
618 | } |
619 | } | |
620 | ||
621 | /* If this is a computed jump, then mark it as | |
622 | reaching everything on the label_value_list | |
623 | and forced_labels list. */ | |
624 | if (computed_jump_p (insn)) | |
625 | { | |
4d1d8045 | 626 | current_function_has_computed_jump = 1; |
2ec1535d | 627 | for (x = label_value_list; x; x = XEXP (x, 1)) |
4d1d8045 BS |
628 | { |
629 | int b = BLOCK_NUM (XEXP (x, 0)); | |
630 | basic_block_computed_jump_target[b] = 1; | |
631 | mark_label_ref (gen_rtx_LABEL_REF (VOIDmode, | |
632 | XEXP (x, 0)), | |
633 | insn, 0); | |
634 | } | |
2ec1535d JL |
635 | |
636 | for (x = forced_labels; x; x = XEXP (x, 1)) | |
4d1d8045 BS |
637 | { |
638 | int b = BLOCK_NUM (XEXP (x, 0)); | |
639 | basic_block_computed_jump_target[b] = 1; | |
640 | mark_label_ref (gen_rtx_LABEL_REF (VOIDmode, | |
641 | XEXP (x, 0)), | |
642 | insn, 0); | |
643 | } | |
644 | } | |
2ec1535d JL |
645 | |
646 | /* If this is a CALL_INSN, then mark it as reaching | |
647 | the active EH handler for this CALL_INSN. If | |
648 | we're handling asynchronous exceptions mark every | |
649 | insn as reaching the active EH handler. | |
650 | ||
651 | Also mark the CALL_INSN as reaching any nonlocal | |
652 | goto sites. */ | |
653 | else if (asynchronous_exceptions | |
654 | || (GET_CODE (insn) == CALL_INSN | |
655 | && ! find_reg_note (insn, REG_RETVAL, | |
656 | NULL_RTX))) | |
657 | { | |
9a0d1e1b AM |
658 | if (active_eh_region[INSN_UID (insn)]) |
659 | { | |
660 | int region; | |
661 | handler_info *ptr; | |
662 | region = active_eh_region[INSN_UID (insn)]; | |
663 | for ( ; region; | |
664 | region = nested_eh_region[region]) | |
665 | { | |
666 | ptr = get_first_handler (region); | |
667 | for ( ; ptr ; ptr = ptr->next) | |
668 | mark_label_ref (gen_rtx_LABEL_REF | |
669 | (VOIDmode, ptr->handler_label), insn, 0); | |
670 | } | |
671 | } | |
2ec1535d JL |
672 | if (!asynchronous_exceptions) |
673 | { | |
674 | for (x = nonlocal_label_list; | |
675 | x; | |
676 | x = XEXP (x, 1)) | |
38a448ca RH |
677 | mark_label_ref (gen_rtx_LABEL_REF (VOIDmode, |
678 | XEXP (x, 0)), | |
2ec1535d | 679 | insn, 0); |
812059fe | 680 | } |
2ec1535d JL |
681 | /* ??? This could be made smarter: |
682 | in some cases it's possible to tell that | |
683 | certain calls will not do a nonlocal goto. | |
684 | ||
685 | For example, if the nested functions that | |
686 | do the nonlocal gotos do not have their | |
687 | addresses taken, then only calls to those | |
688 | functions or to other nested functions that | |
689 | use them could possibly do nonlocal gotos. */ | |
690 | } | |
691 | } | |
692 | } | |
d7429b6a RK |
693 | } |
694 | } | |
695 | ||
2ec1535d JL |
696 | /* This should never happen. If it does that means we've computed an |
697 | incorrect flow graph, which can lead to aborts/crashes later in the | |
698 | compiler or incorrect code generation. | |
af14ce9c | 699 | |
2ec1535d JL |
700 | We used to try and continue here, but that's just asking for trouble |
701 | later during the compile or at runtime. It's easier to debug the | |
702 | problem here than later! */ | |
af14ce9c RK |
703 | for (i = 1; i < n_basic_blocks; i++) |
704 | if (block_live[i] && ! basic_block_drops_in[i] | |
705 | && GET_CODE (basic_block_head[i]) == CODE_LABEL | |
706 | && LABEL_REFS (basic_block_head[i]) == basic_block_head[i]) | |
2ec1535d | 707 | abort (); |
af14ce9c | 708 | |
5ece9746 JL |
709 | /* Now delete the code for any basic blocks that can't be reached. |
710 | They can occur because jump_optimize does not recognize | |
d7429b6a RK |
711 | unreachable loops as unreachable. */ |
712 | ||
8329b5ec | 713 | deleted = 0; |
d7429b6a RK |
714 | for (i = 0; i < n_basic_blocks; i++) |
715 | if (!block_live[i]) | |
716 | { | |
8329b5ec DE |
717 | deleted++; |
718 | ||
719 | /* Delete the insns in a (non-live) block. We physically delete | |
720 | every non-note insn except the start and end (so | |
721 | basic_block_head/end needn't be updated), we turn the latter | |
722 | into NOTE_INSN_DELETED notes. | |
723 | We use to "delete" the insns by turning them into notes, but | |
724 | we may be deleting lots of insns that subsequent passes would | |
725 | otherwise have to process. Secondly, lots of deleted blocks in | |
726 | a row can really slow down propagate_block since it will | |
727 | otherwise process insn-turned-notes multiple times when it | |
728 | looks for loop begin/end notes. */ | |
729 | if (basic_block_head[i] != basic_block_end[i]) | |
730 | { | |
49b6c81e DE |
731 | /* It would be quicker to delete all of these with a single |
732 | unchaining, rather than one at a time, but we need to keep | |
733 | the NOTE's. */ | |
8329b5ec DE |
734 | insn = NEXT_INSN (basic_block_head[i]); |
735 | while (insn != basic_block_end[i]) | |
736 | { | |
737 | if (GET_CODE (insn) == BARRIER) | |
738 | abort (); | |
739 | else if (GET_CODE (insn) != NOTE) | |
740 | insn = flow_delete_insn (insn); | |
741 | else | |
742 | insn = NEXT_INSN (insn); | |
743 | } | |
744 | } | |
d7429b6a | 745 | insn = basic_block_head[i]; |
8329b5ec | 746 | if (GET_CODE (insn) != NOTE) |
d7429b6a | 747 | { |
8329b5ec | 748 | /* Turn the head into a deleted insn note. */ |
d7429b6a RK |
749 | if (GET_CODE (insn) == BARRIER) |
750 | abort (); | |
f8671389 JL |
751 | |
752 | /* If the head of this block is a CODE_LABEL, then it might | |
753 | be the label for an exception handler which can't be | |
754 | reached. | |
755 | ||
756 | We need to remove the label from the exception_handler_label | |
757 | list and remove the associated NOTE_EH_REGION_BEG and | |
758 | NOTE_EH_REGION_END notes. */ | |
759 | if (GET_CODE (insn) == CODE_LABEL) | |
760 | { | |
761 | rtx x, *prev = &exception_handler_labels; | |
762 | ||
763 | for (x = exception_handler_labels; x; x = XEXP (x, 1)) | |
764 | { | |
765 | if (XEXP (x, 0) == insn) | |
766 | { | |
767 | /* Found a match, splice this label out of the | |
768 | EH label list. */ | |
769 | *prev = XEXP (x, 1); | |
770 | XEXP (x, 1) = NULL_RTX; | |
771 | XEXP (x, 0) = NULL_RTX; | |
772 | ||
773 | /* Now we have to find the EH_BEG and EH_END notes | |
774 | associated with this label and remove them. */ | |
775 | ||
9a0d1e1b AM |
776 | #if 0 |
777 | /* Handlers and labels no longer needs to have the same values. | |
778 | If there are no references, scan_region will remove any region | |
779 | labels which are of no use. */ | |
f8671389 JL |
780 | for (x = get_insns (); x; x = NEXT_INSN (x)) |
781 | { | |
782 | if (GET_CODE (x) == NOTE | |
783 | && ((NOTE_LINE_NUMBER (x) | |
784 | == NOTE_INSN_EH_REGION_BEG) | |
785 | || (NOTE_LINE_NUMBER (x) | |
786 | == NOTE_INSN_EH_REGION_END)) | |
787 | && (NOTE_BLOCK_NUMBER (x) | |
788 | == CODE_LABEL_NUMBER (insn))) | |
789 | { | |
790 | NOTE_LINE_NUMBER (x) = NOTE_INSN_DELETED; | |
791 | NOTE_SOURCE_FILE (x) = 0; | |
792 | } | |
793 | } | |
9a0d1e1b | 794 | #endif |
f8671389 JL |
795 | break; |
796 | } | |
797 | prev = &XEXP (x, 1); | |
798 | } | |
799 | } | |
800 | ||
8329b5ec DE |
801 | PUT_CODE (insn, NOTE); |
802 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
803 | NOTE_SOURCE_FILE (insn) = 0; | |
804 | } | |
805 | insn = basic_block_end[i]; | |
806 | if (GET_CODE (insn) != NOTE) | |
807 | { | |
808 | /* Turn the tail into a deleted insn note. */ | |
809 | if (GET_CODE (insn) == BARRIER) | |
810 | abort (); | |
811 | PUT_CODE (insn, NOTE); | |
812 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
813 | NOTE_SOURCE_FILE (insn) = 0; | |
d7429b6a | 814 | } |
8329b5ec DE |
815 | /* BARRIERs are between basic blocks, not part of one. |
816 | Delete a BARRIER if the preceding jump is deleted. | |
817 | We cannot alter a BARRIER into a NOTE | |
818 | because it is too short; but we can really delete | |
819 | it because it is not part of a basic block. */ | |
820 | if (NEXT_INSN (insn) != 0 | |
821 | && GET_CODE (NEXT_INSN (insn)) == BARRIER) | |
822 | delete_insn (NEXT_INSN (insn)); | |
823 | ||
d7429b6a RK |
824 | /* Each time we delete some basic blocks, |
825 | see if there is a jump around them that is | |
826 | being turned into a no-op. If so, delete it. */ | |
827 | ||
828 | if (block_live[i - 1]) | |
829 | { | |
830 | register int j; | |
8329b5ec | 831 | for (j = i + 1; j < n_basic_blocks; j++) |
d7429b6a RK |
832 | if (block_live[j]) |
833 | { | |
834 | rtx label; | |
835 | insn = basic_block_end[i - 1]; | |
836 | if (GET_CODE (insn) == JUMP_INSN | |
837 | /* An unconditional jump is the only possibility | |
838 | we must check for, since a conditional one | |
839 | would make these blocks live. */ | |
840 | && simplejump_p (insn) | |
841 | && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1) | |
842 | && INSN_UID (label) != 0 | |
843 | && BLOCK_NUM (label) == j) | |
844 | { | |
df0c5d2f JL |
845 | int k; |
846 | ||
847 | /* The deleted blocks still show up in the cfg, | |
848 | so we must set basic_block_drops_in for blocks | |
849 | I to J inclusive to keep the cfg accurate. */ | |
850 | for (k = i; k <= j; k++) | |
851 | basic_block_drops_in[k] = 1; | |
852 | ||
d7429b6a RK |
853 | PUT_CODE (insn, NOTE); |
854 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
855 | NOTE_SOURCE_FILE (insn) = 0; | |
856 | if (GET_CODE (NEXT_INSN (insn)) != BARRIER) | |
857 | abort (); | |
858 | delete_insn (NEXT_INSN (insn)); | |
859 | } | |
860 | break; | |
861 | } | |
862 | } | |
863 | } | |
8329b5ec | 864 | |
9faa82d8 | 865 | /* There are pathological cases where one function calling hundreds of |
8329b5ec DE |
866 | nested inline functions can generate lots and lots of unreachable |
867 | blocks that jump can't delete. Since we don't use sparse matrices | |
868 | a lot of memory will be needed to compile such functions. | |
869 | Implementing sparse matrices is a fair bit of work and it is not | |
870 | clear that they win more than they lose (we don't want to | |
871 | unnecessarily slow down compilation of normal code). By making | |
9faa82d8 | 872 | another pass for the pathological case, we can greatly speed up |
8329b5ec DE |
873 | their compilation without hurting normal code. This works because |
874 | all the insns in the unreachable blocks have either been deleted or | |
49b6c81e DE |
875 | turned into notes. |
876 | Note that we're talking about reducing memory usage by 10's of | |
877 | megabytes and reducing compilation time by several minutes. */ | |
8329b5ec DE |
878 | /* ??? The choice of when to make another pass is a bit arbitrary, |
879 | and was derived from empirical data. */ | |
880 | if (pass == 1 | |
49b6c81e | 881 | && deleted > 200) |
8329b5ec DE |
882 | { |
883 | pass++; | |
884 | n_basic_blocks -= deleted; | |
2aec79e2 DE |
885 | /* `n_basic_blocks' may not be correct at this point: two previously |
886 | separate blocks may now be merged. That's ok though as we | |
887 | recalculate it during the second pass. It certainly can't be | |
888 | any larger than the current value. */ | |
8329b5ec DE |
889 | goto restart; |
890 | } | |
d7429b6a RK |
891 | } |
892 | } | |
5ece9746 JL |
893 | |
894 | /* Record INSN's block number as BB. */ | |
895 | ||
896 | void | |
897 | set_block_num (insn, bb) | |
898 | rtx insn; | |
899 | int bb; | |
900 | { | |
901 | if (INSN_UID (insn) >= max_uid_for_flow) | |
902 | { | |
903 | /* Add one-eighth the size so we don't keep calling xrealloc. */ | |
904 | max_uid_for_flow = INSN_UID (insn) + (INSN_UID (insn) + 7) / 8; | |
905 | uid_block_number = (int *) | |
906 | xrealloc (uid_block_number, (max_uid_for_flow + 1) * sizeof (int)); | |
907 | } | |
908 | BLOCK_NUM (insn) = bb; | |
909 | } | |
910 | ||
d7429b6a | 911 | \f |
8329b5ec DE |
912 | /* Subroutines of find_basic_blocks. */ |
913 | ||
d7429b6a RK |
914 | /* Check expression X for label references; |
915 | if one is found, add INSN to the label's chain of references. | |
916 | ||
917 | CHECKDUP means check for and avoid creating duplicate references | |
918 | from the same insn. Such duplicates do no serious harm but | |
919 | can slow life analysis. CHECKDUP is set only when duplicates | |
920 | are likely. */ | |
921 | ||
922 | static void | |
923 | mark_label_ref (x, insn, checkdup) | |
924 | rtx x, insn; | |
925 | int checkdup; | |
926 | { | |
927 | register RTX_CODE code; | |
928 | register int i; | |
929 | register char *fmt; | |
930 | ||
931 | /* We can be called with NULL when scanning label_value_list. */ | |
932 | if (x == 0) | |
933 | return; | |
934 | ||
935 | code = GET_CODE (x); | |
936 | if (code == LABEL_REF) | |
937 | { | |
938 | register rtx label = XEXP (x, 0); | |
939 | register rtx y; | |
940 | if (GET_CODE (label) != CODE_LABEL) | |
941 | abort (); | |
942 | /* If the label was never emitted, this insn is junk, | |
943 | but avoid a crash trying to refer to BLOCK_NUM (label). | |
944 | This can happen as a result of a syntax error | |
945 | and a diagnostic has already been printed. */ | |
946 | if (INSN_UID (label) == 0) | |
947 | return; | |
948 | CONTAINING_INSN (x) = insn; | |
949 | /* if CHECKDUP is set, check for duplicate ref from same insn | |
950 | and don't insert. */ | |
951 | if (checkdup) | |
952 | for (y = LABEL_REFS (label); y != label; y = LABEL_NEXTREF (y)) | |
953 | if (CONTAINING_INSN (y) == insn) | |
954 | return; | |
955 | LABEL_NEXTREF (x) = LABEL_REFS (label); | |
956 | LABEL_REFS (label) = x; | |
957 | block_live_static[BLOCK_NUM (label)] = 1; | |
958 | return; | |
959 | } | |
960 | ||
961 | fmt = GET_RTX_FORMAT (code); | |
962 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
963 | { | |
964 | if (fmt[i] == 'e') | |
965 | mark_label_ref (XEXP (x, i), insn, 0); | |
966 | if (fmt[i] == 'E') | |
967 | { | |
968 | register int j; | |
969 | for (j = 0; j < XVECLEN (x, i); j++) | |
970 | mark_label_ref (XVECEXP (x, i, j), insn, 1); | |
971 | } | |
972 | } | |
973 | } | |
8329b5ec DE |
974 | |
975 | /* Delete INSN by patching it out. | |
976 | Return the next insn. */ | |
977 | ||
978 | static rtx | |
979 | flow_delete_insn (insn) | |
980 | rtx insn; | |
981 | { | |
982 | /* ??? For the moment we assume we don't have to watch for NULLs here | |
983 | since the start/end of basic blocks aren't deleted like this. */ | |
984 | NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn); | |
985 | PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn); | |
986 | return NEXT_INSN (insn); | |
987 | } | |
d7429b6a | 988 | \f |
5ece9746 JL |
989 | /* Perform data flow analysis. |
990 | F is the first insn of the function and NREGS the number of register numbers | |
991 | in use. */ | |
992 | ||
993 | void | |
994 | life_analysis (f, nregs, file) | |
995 | rtx f; | |
996 | int nregs; | |
997 | FILE *file; | |
998 | { | |
5ece9746 | 999 | #ifdef ELIMINABLE_REGS |
ecb06768 | 1000 | register size_t i; |
5ece9746 JL |
1001 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; |
1002 | #endif | |
1003 | ||
1004 | /* Record which registers will be eliminated. We use this in | |
1005 | mark_used_regs. */ | |
1006 | ||
1007 | CLEAR_HARD_REG_SET (elim_reg_set); | |
1008 | ||
1009 | #ifdef ELIMINABLE_REGS | |
1010 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) | |
1011 | SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from); | |
1012 | #else | |
1013 | SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM); | |
1014 | #endif | |
1015 | ||
1016 | life_analysis_1 (f, nregs); | |
1017 | if (file) | |
1018 | dump_flow_info (file); | |
1019 | ||
1020 | free_basic_block_vars (1); | |
1021 | } | |
1022 | ||
1023 | /* Free the variables allocated by find_basic_blocks. | |
1024 | ||
1025 | KEEP_HEAD_END_P is non-zero if basic_block_head and basic_block_end | |
1026 | are not to be freed. */ | |
1027 | ||
1028 | void | |
1029 | free_basic_block_vars (keep_head_end_p) | |
1030 | int keep_head_end_p; | |
1031 | { | |
1032 | if (basic_block_drops_in) | |
1033 | { | |
1034 | free (basic_block_drops_in); | |
1035 | /* Tell dump_flow_info this isn't available anymore. */ | |
1036 | basic_block_drops_in = 0; | |
1037 | } | |
1038 | if (basic_block_loop_depth) | |
1039 | { | |
1040 | free (basic_block_loop_depth); | |
1041 | basic_block_loop_depth = 0; | |
1042 | } | |
1043 | if (uid_block_number) | |
1044 | { | |
1045 | free (uid_block_number); | |
1046 | uid_block_number = 0; | |
1047 | } | |
1048 | if (uid_volatile) | |
1049 | { | |
1050 | free (uid_volatile); | |
1051 | uid_volatile = 0; | |
1052 | } | |
1053 | ||
1054 | if (! keep_head_end_p && basic_block_head) | |
1055 | { | |
1056 | free (basic_block_head); | |
1057 | basic_block_head = 0; | |
1058 | free (basic_block_end); | |
1059 | basic_block_end = 0; | |
1060 | } | |
1061 | } | |
1062 | ||
d7429b6a RK |
1063 | /* Determine which registers are live at the start of each |
1064 | basic block of the function whose first insn is F. | |
1065 | NREGS is the number of registers used in F. | |
1066 | We allocate the vector basic_block_live_at_start | |
1067 | and the regsets that it points to, and fill them with the data. | |
1068 | regset_size and regset_bytes are also set here. */ | |
1069 | ||
1070 | static void | |
5ece9746 | 1071 | life_analysis_1 (f, nregs) |
d7429b6a RK |
1072 | rtx f; |
1073 | int nregs; | |
1074 | { | |
d7429b6a RK |
1075 | int first_pass; |
1076 | int changed; | |
1077 | /* For each basic block, a bitmask of regs | |
1078 | live on exit from the block. */ | |
1079 | regset *basic_block_live_at_end; | |
1080 | /* For each basic block, a bitmask of regs | |
1081 | live on entry to a successor-block of this block. | |
1082 | If this does not match basic_block_live_at_end, | |
1083 | that must be updated, and the block must be rescanned. */ | |
1084 | regset *basic_block_new_live_at_end; | |
1085 | /* For each basic block, a bitmask of regs | |
1086 | whose liveness at the end of the basic block | |
1087 | can make a difference in which regs are live on entry to the block. | |
1088 | These are the regs that are set within the basic block, | |
1089 | possibly excluding those that are used after they are set. */ | |
1090 | regset *basic_block_significant; | |
1091 | register int i; | |
1092 | rtx insn; | |
1093 | ||
1094 | struct obstack flow_obstack; | |
1095 | ||
1096 | gcc_obstack_init (&flow_obstack); | |
1097 | ||
1098 | max_regno = nregs; | |
1099 | ||
1100 | bzero (regs_ever_live, sizeof regs_ever_live); | |
1101 | ||
1102 | /* Allocate and zero out many data structures | |
1103 | that will record the data from lifetime analysis. */ | |
1104 | ||
1105 | allocate_for_life_analysis (); | |
1106 | ||
1107 | reg_next_use = (rtx *) alloca (nregs * sizeof (rtx)); | |
4c9a05bc | 1108 | bzero ((char *) reg_next_use, nregs * sizeof (rtx)); |
d7429b6a RK |
1109 | |
1110 | /* Set up several regset-vectors used internally within this function. | |
1111 | Their meanings are documented above, with their declarations. */ | |
1112 | ||
4c9a05bc RK |
1113 | basic_block_live_at_end |
1114 | = (regset *) alloca (n_basic_blocks * sizeof (regset)); | |
1115 | ||
d7429b6a RK |
1116 | /* Don't use alloca since that leads to a crash rather than an error message |
1117 | if there isn't enough space. | |
1118 | Don't use oballoc since we may need to allocate other things during | |
1119 | this function on the temporary obstack. */ | |
67f0e213 | 1120 | init_regset_vector (basic_block_live_at_end, n_basic_blocks, &flow_obstack); |
d7429b6a | 1121 | |
4c9a05bc RK |
1122 | basic_block_new_live_at_end |
1123 | = (regset *) alloca (n_basic_blocks * sizeof (regset)); | |
67f0e213 | 1124 | init_regset_vector (basic_block_new_live_at_end, n_basic_blocks, |
7eb136d6 | 1125 | &flow_obstack); |
d7429b6a | 1126 | |
4c9a05bc RK |
1127 | basic_block_significant |
1128 | = (regset *) alloca (n_basic_blocks * sizeof (regset)); | |
67f0e213 | 1129 | init_regset_vector (basic_block_significant, n_basic_blocks, &flow_obstack); |
d7429b6a RK |
1130 | |
1131 | /* Record which insns refer to any volatile memory | |
1132 | or for any reason can't be deleted just because they are dead stores. | |
0f41302f | 1133 | Also, delete any insns that copy a register to itself. */ |
d7429b6a RK |
1134 | |
1135 | for (insn = f; insn; insn = NEXT_INSN (insn)) | |
1136 | { | |
1137 | enum rtx_code code1 = GET_CODE (insn); | |
1138 | if (code1 == CALL_INSN) | |
1139 | INSN_VOLATILE (insn) = 1; | |
1140 | else if (code1 == INSN || code1 == JUMP_INSN) | |
1141 | { | |
1142 | /* Delete (in effect) any obvious no-op moves. */ | |
1143 | if (GET_CODE (PATTERN (insn)) == SET | |
1144 | && GET_CODE (SET_DEST (PATTERN (insn))) == REG | |
1145 | && GET_CODE (SET_SRC (PATTERN (insn))) == REG | |
db3cf6fb MS |
1146 | && (REGNO (SET_DEST (PATTERN (insn))) |
1147 | == REGNO (SET_SRC (PATTERN (insn)))) | |
d7429b6a | 1148 | /* Insns carrying these notes are useful later on. */ |
5f4f0e22 | 1149 | && ! find_reg_note (insn, REG_EQUAL, NULL_RTX)) |
d7429b6a RK |
1150 | { |
1151 | PUT_CODE (insn, NOTE); | |
1152 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
1153 | NOTE_SOURCE_FILE (insn) = 0; | |
1154 | } | |
ac684a20 JL |
1155 | /* Delete (in effect) any obvious no-op moves. */ |
1156 | else if (GET_CODE (PATTERN (insn)) == SET | |
1157 | && GET_CODE (SET_DEST (PATTERN (insn))) == SUBREG | |
1158 | && GET_CODE (SUBREG_REG (SET_DEST (PATTERN (insn)))) == REG | |
1159 | && GET_CODE (SET_SRC (PATTERN (insn))) == SUBREG | |
1160 | && GET_CODE (SUBREG_REG (SET_SRC (PATTERN (insn)))) == REG | |
db3cf6fb MS |
1161 | && (REGNO (SUBREG_REG (SET_DEST (PATTERN (insn)))) |
1162 | == REGNO (SUBREG_REG (SET_SRC (PATTERN (insn))))) | |
ac684a20 JL |
1163 | && SUBREG_WORD (SET_DEST (PATTERN (insn))) == |
1164 | SUBREG_WORD (SET_SRC (PATTERN (insn))) | |
1165 | /* Insns carrying these notes are useful later on. */ | |
1166 | && ! find_reg_note (insn, REG_EQUAL, NULL_RTX)) | |
1167 | { | |
1168 | PUT_CODE (insn, NOTE); | |
1169 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
1170 | NOTE_SOURCE_FILE (insn) = 0; | |
1171 | } | |
d7429b6a RK |
1172 | else if (GET_CODE (PATTERN (insn)) == PARALLEL) |
1173 | { | |
1174 | /* If nothing but SETs of registers to themselves, | |
1175 | this insn can also be deleted. */ | |
1176 | for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) | |
1177 | { | |
1178 | rtx tem = XVECEXP (PATTERN (insn), 0, i); | |
1179 | ||
1180 | if (GET_CODE (tem) == USE | |
1181 | || GET_CODE (tem) == CLOBBER) | |
1182 | continue; | |
1183 | ||
1184 | if (GET_CODE (tem) != SET | |
1185 | || GET_CODE (SET_DEST (tem)) != REG | |
1186 | || GET_CODE (SET_SRC (tem)) != REG | |
1187 | || REGNO (SET_DEST (tem)) != REGNO (SET_SRC (tem))) | |
1188 | break; | |
1189 | } | |
1190 | ||
1191 | if (i == XVECLEN (PATTERN (insn), 0) | |
1192 | /* Insns carrying these notes are useful later on. */ | |
5f4f0e22 | 1193 | && ! find_reg_note (insn, REG_EQUAL, NULL_RTX)) |
d7429b6a RK |
1194 | { |
1195 | PUT_CODE (insn, NOTE); | |
1196 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
1197 | NOTE_SOURCE_FILE (insn) = 0; | |
1198 | } | |
1199 | else | |
1200 | INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn)); | |
1201 | } | |
1202 | else if (GET_CODE (PATTERN (insn)) != USE) | |
1203 | INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn)); | |
1204 | /* A SET that makes space on the stack cannot be dead. | |
1205 | (Such SETs occur only for allocating variable-size data, | |
1206 | so they will always have a PLUS or MINUS according to the | |
1207 | direction of stack growth.) | |
1208 | Even if this function never uses this stack pointer value, | |
1209 | signal handlers do! */ | |
1210 | else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET | |
1211 | && SET_DEST (PATTERN (insn)) == stack_pointer_rtx | |
1212 | #ifdef STACK_GROWS_DOWNWARD | |
1213 | && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS | |
1214 | #else | |
1215 | && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS | |
1216 | #endif | |
1217 | && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx) | |
1218 | INSN_VOLATILE (insn) = 1; | |
1219 | } | |
1220 | } | |
1221 | ||
1222 | if (n_basic_blocks > 0) | |
1223 | #ifdef EXIT_IGNORE_STACK | |
1224 | if (! EXIT_IGNORE_STACK | |
0200b5ed JL |
1225 | || (! FRAME_POINTER_REQUIRED |
1226 | && ! current_function_calls_alloca | |
1227 | && flag_omit_frame_pointer)) | |
d7429b6a RK |
1228 | #endif |
1229 | { | |
1230 | /* If exiting needs the right stack value, | |
1231 | consider the stack pointer live at the end of the function. */ | |
916b1701 MM |
1232 | SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], |
1233 | STACK_POINTER_REGNUM); | |
1234 | SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], | |
1235 | STACK_POINTER_REGNUM); | |
d7429b6a RK |
1236 | } |
1237 | ||
fe0f9c4b RK |
1238 | /* Mark the frame pointer is needed at the end of the function. If |
1239 | we end up eliminating it, it will be removed from the live list | |
1240 | of each basic block by reload. */ | |
1241 | ||
1242 | if (n_basic_blocks > 0) | |
1243 | { | |
916b1701 MM |
1244 | SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], |
1245 | FRAME_POINTER_REGNUM); | |
1246 | SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], | |
1247 | FRAME_POINTER_REGNUM); | |
73a187c1 DE |
1248 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
1249 | /* If they are different, also mark the hard frame pointer as live */ | |
916b1701 MM |
1250 | SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], |
1251 | HARD_FRAME_POINTER_REGNUM); | |
1252 | SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], | |
1253 | HARD_FRAME_POINTER_REGNUM); | |
73a187c1 | 1254 | #endif |
fe0f9c4b RK |
1255 | } |
1256 | ||
632c9d9e MS |
1257 | /* Mark all global registers and all registers used by the epilogue |
1258 | as being live at the end of the function since they may be | |
1259 | referenced by our caller. */ | |
d7429b6a RK |
1260 | |
1261 | if (n_basic_blocks > 0) | |
1262 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
632c9d9e MS |
1263 | if (global_regs[i] |
1264 | #ifdef EPILOGUE_USES | |
1265 | || EPILOGUE_USES (i) | |
1266 | #endif | |
1267 | ) | |
d7429b6a | 1268 | { |
916b1701 MM |
1269 | SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], i); |
1270 | SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], i); | |
d7429b6a RK |
1271 | } |
1272 | ||
1273 | /* Propagate life info through the basic blocks | |
1274 | around the graph of basic blocks. | |
1275 | ||
1276 | This is a relaxation process: each time a new register | |
1277 | is live at the end of the basic block, we must scan the block | |
1278 | to determine which registers are, as a consequence, live at the beginning | |
1279 | of that block. These registers must then be marked live at the ends | |
1280 | of all the blocks that can transfer control to that block. | |
1281 | The process continues until it reaches a fixed point. */ | |
1282 | ||
1283 | first_pass = 1; | |
1284 | changed = 1; | |
1285 | while (changed) | |
1286 | { | |
1287 | changed = 0; | |
1288 | for (i = n_basic_blocks - 1; i >= 0; i--) | |
1289 | { | |
1290 | int consider = first_pass; | |
1291 | int must_rescan = first_pass; | |
1292 | register int j; | |
1293 | ||
1294 | if (!first_pass) | |
1295 | { | |
1296 | /* Set CONSIDER if this block needs thinking about at all | |
1297 | (that is, if the regs live now at the end of it | |
1298 | are not the same as were live at the end of it when | |
1299 | we last thought about it). | |
1300 | Set must_rescan if it needs to be thought about | |
1301 | instruction by instruction (that is, if any additional | |
1302 | reg that is live at the end now but was not live there before | |
1303 | is one of the significant regs of this basic block). */ | |
1304 | ||
b5835272 RK |
1305 | EXECUTE_IF_AND_COMPL_IN_REG_SET |
1306 | (basic_block_new_live_at_end[i], | |
1307 | basic_block_live_at_end[i], 0, j, | |
1308 | { | |
1309 | consider = 1; | |
1310 | if (REGNO_REG_SET_P (basic_block_significant[i], j)) | |
1311 | { | |
1312 | must_rescan = 1; | |
1313 | goto done; | |
1314 | } | |
1315 | }); | |
916b1701 | 1316 | done: |
d7429b6a RK |
1317 | if (! consider) |
1318 | continue; | |
1319 | } | |
1320 | ||
1321 | /* The live_at_start of this block may be changing, | |
1322 | so another pass will be required after this one. */ | |
1323 | changed = 1; | |
1324 | ||
1325 | if (! must_rescan) | |
1326 | { | |
1327 | /* No complete rescan needed; | |
1328 | just record those variables newly known live at end | |
1329 | as live at start as well. */ | |
916b1701 MM |
1330 | IOR_AND_COMPL_REG_SET (basic_block_live_at_start[i], |
1331 | basic_block_new_live_at_end[i], | |
1332 | basic_block_live_at_end[i]); | |
1333 | ||
1334 | IOR_AND_COMPL_REG_SET (basic_block_live_at_end[i], | |
1335 | basic_block_new_live_at_end[i], | |
1336 | basic_block_live_at_end[i]); | |
d7429b6a RK |
1337 | } |
1338 | else | |
1339 | { | |
1340 | /* Update the basic_block_live_at_start | |
1341 | by propagation backwards through the block. */ | |
916b1701 MM |
1342 | COPY_REG_SET (basic_block_live_at_end[i], |
1343 | basic_block_new_live_at_end[i]); | |
1344 | COPY_REG_SET (basic_block_live_at_start[i], | |
1345 | basic_block_live_at_end[i]); | |
d7429b6a RK |
1346 | propagate_block (basic_block_live_at_start[i], |
1347 | basic_block_head[i], basic_block_end[i], 0, | |
5f4f0e22 CH |
1348 | first_pass ? basic_block_significant[i] |
1349 | : (regset) 0, | |
d7429b6a RK |
1350 | i); |
1351 | } | |
1352 | ||
1353 | { | |
1354 | register rtx jump, head; | |
af14ce9c | 1355 | |
d7429b6a RK |
1356 | /* Update the basic_block_new_live_at_end's of the block |
1357 | that falls through into this one (if any). */ | |
1358 | head = basic_block_head[i]; | |
d7429b6a | 1359 | if (basic_block_drops_in[i]) |
916b1701 MM |
1360 | IOR_REG_SET (basic_block_new_live_at_end[i-1], |
1361 | basic_block_live_at_start[i]); | |
af14ce9c | 1362 | |
d7429b6a RK |
1363 | /* Update the basic_block_new_live_at_end's of |
1364 | all the blocks that jump to this one. */ | |
1365 | if (GET_CODE (head) == CODE_LABEL) | |
1366 | for (jump = LABEL_REFS (head); | |
1367 | jump != head; | |
1368 | jump = LABEL_NEXTREF (jump)) | |
1369 | { | |
1370 | register int from_block = BLOCK_NUM (CONTAINING_INSN (jump)); | |
916b1701 MM |
1371 | IOR_REG_SET (basic_block_new_live_at_end[from_block], |
1372 | basic_block_live_at_start[i]); | |
d7429b6a RK |
1373 | } |
1374 | } | |
1375 | #ifdef USE_C_ALLOCA | |
1376 | alloca (0); | |
1377 | #endif | |
1378 | } | |
1379 | first_pass = 0; | |
1380 | } | |
1381 | ||
1382 | /* The only pseudos that are live at the beginning of the function are | |
1383 | those that were not set anywhere in the function. local-alloc doesn't | |
1384 | know how to handle these correctly, so mark them as not local to any | |
1385 | one basic block. */ | |
1386 | ||
1387 | if (n_basic_blocks > 0) | |
916b1701 MM |
1388 | EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[0], |
1389 | FIRST_PSEUDO_REGISTER, i, | |
1390 | { | |
1391 | REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; | |
1392 | }); | |
d7429b6a RK |
1393 | |
1394 | /* Now the life information is accurate. | |
1395 | Make one more pass over each basic block | |
1396 | to delete dead stores, create autoincrement addressing | |
1397 | and record how many times each register is used, is set, or dies. | |
1398 | ||
1399 | To save time, we operate directly in basic_block_live_at_end[i], | |
1400 | thus destroying it (in fact, converting it into a copy of | |
1401 | basic_block_live_at_start[i]). This is ok now because | |
1402 | basic_block_live_at_end[i] is no longer used past this point. */ | |
1403 | ||
1404 | max_scratch = 0; | |
1405 | ||
1406 | for (i = 0; i < n_basic_blocks; i++) | |
1407 | { | |
1408 | propagate_block (basic_block_live_at_end[i], | |
5f4f0e22 CH |
1409 | basic_block_head[i], basic_block_end[i], 1, |
1410 | (regset) 0, i); | |
d7429b6a RK |
1411 | #ifdef USE_C_ALLOCA |
1412 | alloca (0); | |
1413 | #endif | |
1414 | } | |
1415 | ||
1416 | #if 0 | |
1417 | /* Something live during a setjmp should not be put in a register | |
1418 | on certain machines which restore regs from stack frames | |
1419 | rather than from the jmpbuf. | |
1420 | But we don't need to do this for the user's variables, since | |
1421 | ANSI says only volatile variables need this. */ | |
1422 | #ifdef LONGJMP_RESTORE_FROM_STACK | |
916b1701 MM |
1423 | EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp, |
1424 | FIRST_PSEUDO_REGISTER, i, | |
1425 | { | |
1426 | if (regno_reg_rtx[i] != 0 | |
1427 | && ! REG_USERVAR_P (regno_reg_rtx[i])) | |
1428 | { | |
1429 | REG_LIVE_LENGTH (i) = -1; | |
1430 | REG_BASIC_BLOCK (i) = -1; | |
1431 | } | |
1432 | }); | |
d7429b6a RK |
1433 | #endif |
1434 | #endif | |
1435 | ||
1436 | /* We have a problem with any pseudoreg that | |
1437 | lives across the setjmp. ANSI says that if a | |
1438 | user variable does not change in value | |
1439 | between the setjmp and the longjmp, then the longjmp preserves it. | |
1440 | This includes longjmp from a place where the pseudo appears dead. | |
1441 | (In principle, the value still exists if it is in scope.) | |
1442 | If the pseudo goes in a hard reg, some other value may occupy | |
1443 | that hard reg where this pseudo is dead, thus clobbering the pseudo. | |
1444 | Conclusion: such a pseudo must not go in a hard reg. */ | |
916b1701 MM |
1445 | EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp, |
1446 | FIRST_PSEUDO_REGISTER, i, | |
1447 | { | |
1448 | if (regno_reg_rtx[i] != 0) | |
1449 | { | |
1450 | REG_LIVE_LENGTH (i) = -1; | |
1451 | REG_BASIC_BLOCK (i) = -1; | |
1452 | } | |
1453 | }); | |
d7429b6a | 1454 | |
67f0e213 RK |
1455 | |
1456 | free_regset_vector (basic_block_live_at_end, n_basic_blocks); | |
1457 | free_regset_vector (basic_block_new_live_at_end, n_basic_blocks); | |
1458 | free_regset_vector (basic_block_significant, n_basic_blocks); | |
1459 | basic_block_live_at_end = (regset *)0; | |
1460 | basic_block_new_live_at_end = (regset *)0; | |
1461 | basic_block_significant = (regset *)0; | |
1462 | ||
5f4f0e22 | 1463 | obstack_free (&flow_obstack, NULL_PTR); |
d7429b6a RK |
1464 | } |
1465 | \f | |
1466 | /* Subroutines of life analysis. */ | |
1467 | ||
1468 | /* Allocate the permanent data structures that represent the results | |
1469 | of life analysis. Not static since used also for stupid life analysis. */ | |
1470 | ||
1471 | void | |
1472 | allocate_for_life_analysis () | |
1473 | { | |
1474 | register int i; | |
d7429b6a | 1475 | |
67f0e213 RK |
1476 | /* Recalculate the register space, in case it has grown. Old style |
1477 | vector oriented regsets would set regset_{size,bytes} here also. */ | |
1478 | allocate_reg_info (max_regno, FALSE, FALSE); | |
d7429b6a | 1479 | |
b1f21e0a MM |
1480 | /* Because both reg_scan and flow_analysis want to set up the REG_N_SETS |
1481 | information, explicitly reset it here. The allocation should have | |
1482 | already happened on the previous reg_scan pass. Make sure in case | |
1483 | some more registers were allocated. */ | |
d7429b6a | 1484 | for (i = 0; i < max_regno; i++) |
b1f21e0a | 1485 | REG_N_SETS (i) = 0; |
d7429b6a | 1486 | |
4c9a05bc RK |
1487 | basic_block_live_at_start |
1488 | = (regset *) oballoc (n_basic_blocks * sizeof (regset)); | |
67f0e213 | 1489 | init_regset_vector (basic_block_live_at_start, n_basic_blocks, |
7eb136d6 | 1490 | function_obstack); |
d7429b6a | 1491 | |
7eb136d6 MM |
1492 | regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack); |
1493 | CLEAR_REG_SET (regs_live_at_setjmp); | |
d7429b6a RK |
1494 | } |
1495 | ||
67f0e213 RK |
1496 | /* Make each element of VECTOR point at a regset. The vector has |
1497 | NELTS elements, and space is allocated from the ALLOC_OBSTACK | |
1498 | obstack. */ | |
d7429b6a | 1499 | |
67f0e213 RK |
1500 | void |
1501 | init_regset_vector (vector, nelts, alloc_obstack) | |
d7429b6a | 1502 | regset *vector; |
d7429b6a | 1503 | int nelts; |
7eb136d6 | 1504 | struct obstack *alloc_obstack; |
d7429b6a RK |
1505 | { |
1506 | register int i; | |
d7429b6a RK |
1507 | |
1508 | for (i = 0; i < nelts; i++) | |
1509 | { | |
7eb136d6 MM |
1510 | vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack); |
1511 | CLEAR_REG_SET (vector[i]); | |
d7429b6a RK |
1512 | } |
1513 | } | |
e658434c | 1514 | |
67f0e213 RK |
1515 | /* Release any additional space allocated for each element of VECTOR point |
1516 | other than the regset header itself. The vector has NELTS elements. */ | |
1517 | ||
1518 | void | |
1519 | free_regset_vector (vector, nelts) | |
1520 | regset *vector; | |
1521 | int nelts; | |
1522 | { | |
1523 | register int i; | |
1524 | ||
1525 | for (i = 0; i < nelts; i++) | |
1526 | FREE_REG_SET (vector[i]); | |
1527 | } | |
1528 | ||
d7429b6a RK |
1529 | /* Compute the registers live at the beginning of a basic block |
1530 | from those live at the end. | |
1531 | ||
1532 | When called, OLD contains those live at the end. | |
1533 | On return, it contains those live at the beginning. | |
1534 | FIRST and LAST are the first and last insns of the basic block. | |
1535 | ||
1536 | FINAL is nonzero if we are doing the final pass which is not | |
1537 | for computing the life info (since that has already been done) | |
1538 | but for acting on it. On this pass, we delete dead stores, | |
1539 | set up the logical links and dead-variables lists of instructions, | |
1540 | and merge instructions for autoincrement and autodecrement addresses. | |
1541 | ||
1542 | SIGNIFICANT is nonzero only the first time for each basic block. | |
1543 | If it is nonzero, it points to a regset in which we store | |
1544 | a 1 for each register that is set within the block. | |
1545 | ||
1546 | BNUM is the number of the basic block. */ | |
1547 | ||
1548 | static void | |
1549 | propagate_block (old, first, last, final, significant, bnum) | |
1550 | register regset old; | |
1551 | rtx first; | |
1552 | rtx last; | |
1553 | int final; | |
1554 | regset significant; | |
1555 | int bnum; | |
1556 | { | |
1557 | register rtx insn; | |
1558 | rtx prev; | |
1559 | regset live; | |
1560 | regset dead; | |
1561 | ||
1562 | /* The following variables are used only if FINAL is nonzero. */ | |
1563 | /* This vector gets one element for each reg that has been live | |
1564 | at any point in the basic block that has been scanned so far. | |
916b1701 MM |
1565 | SOMETIMES_MAX says how many elements are in use so far. */ |
1566 | register int *regs_sometimes_live; | |
d7429b6a RK |
1567 | int sometimes_max = 0; |
1568 | /* This regset has 1 for each reg that we have seen live so far. | |
1569 | It and REGS_SOMETIMES_LIVE are updated together. */ | |
1570 | regset maxlive; | |
1571 | ||
1572 | /* The loop depth may change in the middle of a basic block. Since we | |
1573 | scan from end to beginning, we start with the depth at the end of the | |
1574 | current basic block, and adjust as we pass ends and starts of loops. */ | |
1575 | loop_depth = basic_block_loop_depth[bnum]; | |
1576 | ||
7eb136d6 MM |
1577 | dead = ALLOCA_REG_SET (); |
1578 | live = ALLOCA_REG_SET (); | |
d7429b6a RK |
1579 | |
1580 | cc0_live = 0; | |
1581 | last_mem_set = 0; | |
1582 | ||
1583 | /* Include any notes at the end of the block in the scan. | |
1584 | This is in case the block ends with a call to setjmp. */ | |
1585 | ||
1586 | while (NEXT_INSN (last) != 0 && GET_CODE (NEXT_INSN (last)) == NOTE) | |
1587 | { | |
1588 | /* Look for loop boundaries, we are going forward here. */ | |
1589 | last = NEXT_INSN (last); | |
1590 | if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_BEG) | |
1591 | loop_depth++; | |
1592 | else if (NOTE_LINE_NUMBER (last) == NOTE_INSN_LOOP_END) | |
1593 | loop_depth--; | |
1594 | } | |
1595 | ||
1596 | if (final) | |
1597 | { | |
916b1701 | 1598 | register int i; |
d7429b6a RK |
1599 | |
1600 | num_scratch = 0; | |
7eb136d6 | 1601 | maxlive = ALLOCA_REG_SET (); |
916b1701 MM |
1602 | COPY_REG_SET (maxlive, old); |
1603 | regs_sometimes_live = (int *) alloca (max_regno * sizeof (int)); | |
d7429b6a RK |
1604 | |
1605 | /* Process the regs live at the end of the block. | |
1606 | Enter them in MAXLIVE and REGS_SOMETIMES_LIVE. | |
916b1701 MM |
1607 | Also mark them as not local to any one basic block. */ |
1608 | EXECUTE_IF_SET_IN_REG_SET (old, 0, i, | |
1609 | { | |
1610 | REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; | |
1611 | regs_sometimes_live[sometimes_max] = i; | |
1612 | sometimes_max++; | |
1613 | }); | |
d7429b6a RK |
1614 | } |
1615 | ||
1616 | /* Scan the block an insn at a time from end to beginning. */ | |
1617 | ||
1618 | for (insn = last; ; insn = prev) | |
1619 | { | |
1620 | prev = PREV_INSN (insn); | |
1621 | ||
8329b5ec | 1622 | if (GET_CODE (insn) == NOTE) |
d7429b6a | 1623 | { |
8329b5ec DE |
1624 | /* Look for loop boundaries, remembering that we are going |
1625 | backwards. */ | |
1626 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
1627 | loop_depth++; | |
1628 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
1629 | loop_depth--; | |
1630 | ||
1631 | /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. | |
1632 | Abort now rather than setting register status incorrectly. */ | |
1633 | if (loop_depth == 0) | |
1634 | abort (); | |
1635 | ||
1636 | /* If this is a call to `setjmp' et al, | |
1637 | warn if any non-volatile datum is live. */ | |
1638 | ||
1639 | if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP) | |
916b1701 | 1640 | IOR_REG_SET (regs_live_at_setjmp, old); |
d7429b6a RK |
1641 | } |
1642 | ||
1643 | /* Update the life-status of regs for this insn. | |
1644 | First DEAD gets which regs are set in this insn | |
1645 | then LIVE gets which regs are used in this insn. | |
1646 | Then the regs live before the insn | |
1647 | are those live after, with DEAD regs turned off, | |
1648 | and then LIVE regs turned on. */ | |
1649 | ||
8329b5ec | 1650 | else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
d7429b6a RK |
1651 | { |
1652 | register int i; | |
5f4f0e22 | 1653 | rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX); |
d7429b6a RK |
1654 | int insn_is_dead |
1655 | = (insn_dead_p (PATTERN (insn), old, 0) | |
1656 | /* Don't delete something that refers to volatile storage! */ | |
1657 | && ! INSN_VOLATILE (insn)); | |
1658 | int libcall_is_dead | |
1659 | = (insn_is_dead && note != 0 | |
1660 | && libcall_dead_p (PATTERN (insn), old, note, insn)); | |
1661 | ||
1662 | /* If an instruction consists of just dead store(s) on final pass, | |
1663 | "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED. | |
1664 | We could really delete it with delete_insn, but that | |
1665 | can cause trouble for first or last insn in a basic block. */ | |
1666 | if (final && insn_is_dead) | |
1667 | { | |
1668 | PUT_CODE (insn, NOTE); | |
1669 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
1670 | NOTE_SOURCE_FILE (insn) = 0; | |
1671 | ||
e5df1ea3 RK |
1672 | /* CC0 is now known to be dead. Either this insn used it, |
1673 | in which case it doesn't anymore, or clobbered it, | |
1674 | so the next insn can't use it. */ | |
1675 | cc0_live = 0; | |
1676 | ||
d7429b6a RK |
1677 | /* If this insn is copying the return value from a library call, |
1678 | delete the entire library call. */ | |
1679 | if (libcall_is_dead) | |
1680 | { | |
1681 | rtx first = XEXP (note, 0); | |
1682 | rtx p = insn; | |
1683 | while (INSN_DELETED_P (first)) | |
1684 | first = NEXT_INSN (first); | |
1685 | while (p != first) | |
1686 | { | |
1687 | p = PREV_INSN (p); | |
1688 | PUT_CODE (p, NOTE); | |
1689 | NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED; | |
1690 | NOTE_SOURCE_FILE (p) = 0; | |
1691 | } | |
1692 | } | |
1693 | goto flushed; | |
1694 | } | |
1695 | ||
916b1701 MM |
1696 | CLEAR_REG_SET (dead); |
1697 | CLEAR_REG_SET (live); | |
d7429b6a RK |
1698 | |
1699 | /* See if this is an increment or decrement that can be | |
1700 | merged into a following memory address. */ | |
1701 | #ifdef AUTO_INC_DEC | |
1702 | { | |
956d6950 JL |
1703 | register rtx x = single_set (insn); |
1704 | ||
d7429b6a | 1705 | /* Does this instruction increment or decrement a register? */ |
956d6950 | 1706 | if (final && x != 0 |
d7429b6a RK |
1707 | && GET_CODE (SET_DEST (x)) == REG |
1708 | && (GET_CODE (SET_SRC (x)) == PLUS | |
1709 | || GET_CODE (SET_SRC (x)) == MINUS) | |
1710 | && XEXP (SET_SRC (x), 0) == SET_DEST (x) | |
1711 | && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT | |
1712 | /* Ok, look for a following memory ref we can combine with. | |
1713 | If one is found, change the memory ref to a PRE_INC | |
1714 | or PRE_DEC, cancel this insn, and return 1. | |
1715 | Return 0 if nothing has been done. */ | |
1716 | && try_pre_increment_1 (insn)) | |
1717 | goto flushed; | |
1718 | } | |
1719 | #endif /* AUTO_INC_DEC */ | |
1720 | ||
1721 | /* If this is not the final pass, and this insn is copying the | |
1722 | value of a library call and it's dead, don't scan the | |
1723 | insns that perform the library call, so that the call's | |
1724 | arguments are not marked live. */ | |
1725 | if (libcall_is_dead) | |
1726 | { | |
1727 | /* Mark the dest reg as `significant'. */ | |
5f4f0e22 | 1728 | mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant); |
d7429b6a RK |
1729 | |
1730 | insn = XEXP (note, 0); | |
1731 | prev = PREV_INSN (insn); | |
1732 | } | |
1733 | else if (GET_CODE (PATTERN (insn)) == SET | |
1734 | && SET_DEST (PATTERN (insn)) == stack_pointer_rtx | |
1735 | && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS | |
1736 | && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx | |
1737 | && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT) | |
1738 | /* We have an insn to pop a constant amount off the stack. | |
1739 | (Such insns use PLUS regardless of the direction of the stack, | |
1740 | and any insn to adjust the stack by a constant is always a pop.) | |
1741 | These insns, if not dead stores, have no effect on life. */ | |
1742 | ; | |
1743 | else | |
1744 | { | |
1745 | /* LIVE gets the regs used in INSN; | |
1746 | DEAD gets those set by it. Dead insns don't make anything | |
1747 | live. */ | |
1748 | ||
5f4f0e22 CH |
1749 | mark_set_regs (old, dead, PATTERN (insn), |
1750 | final ? insn : NULL_RTX, significant); | |
d7429b6a RK |
1751 | |
1752 | /* If an insn doesn't use CC0, it becomes dead since we | |
1753 | assume that every insn clobbers it. So show it dead here; | |
1754 | mark_used_regs will set it live if it is referenced. */ | |
1755 | cc0_live = 0; | |
1756 | ||
1757 | if (! insn_is_dead) | |
1758 | mark_used_regs (old, live, PATTERN (insn), final, insn); | |
1759 | ||
1760 | /* Sometimes we may have inserted something before INSN (such as | |
1761 | a move) when we make an auto-inc. So ensure we will scan | |
1762 | those insns. */ | |
1763 | #ifdef AUTO_INC_DEC | |
1764 | prev = PREV_INSN (insn); | |
1765 | #endif | |
1766 | ||
1767 | if (! insn_is_dead && GET_CODE (insn) == CALL_INSN) | |
1768 | { | |
1769 | register int i; | |
1770 | ||
6b67ec08 RK |
1771 | rtx note; |
1772 | ||
1773 | for (note = CALL_INSN_FUNCTION_USAGE (insn); | |
1774 | note; | |
1775 | note = XEXP (note, 1)) | |
1776 | if (GET_CODE (XEXP (note, 0)) == USE) | |
1777 | mark_used_regs (old, live, SET_DEST (XEXP (note, 0)), | |
1778 | final, insn); | |
1779 | ||
d7429b6a | 1780 | /* Each call clobbers all call-clobbered regs that are not |
e4329280 | 1781 | global or fixed. Note that the function-value reg is a |
d7429b6a RK |
1782 | call-clobbered reg, and mark_set_regs has already had |
1783 | a chance to handle it. */ | |
1784 | ||
1785 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
e4329280 RK |
1786 | if (call_used_regs[i] && ! global_regs[i] |
1787 | && ! fixed_regs[i]) | |
916b1701 | 1788 | SET_REGNO_REG_SET (dead, i); |
d7429b6a RK |
1789 | |
1790 | /* The stack ptr is used (honorarily) by a CALL insn. */ | |
916b1701 | 1791 | SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
d7429b6a RK |
1792 | |
1793 | /* Calls may also reference any of the global registers, | |
1794 | so they are made live. */ | |
d7429b6a RK |
1795 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
1796 | if (global_regs[i]) | |
9b316aa2 | 1797 | mark_used_regs (old, live, |
38a448ca | 1798 | gen_rtx_REG (reg_raw_mode[i], i), |
9b316aa2 | 1799 | final, insn); |
d7429b6a RK |
1800 | |
1801 | /* Calls also clobber memory. */ | |
1802 | last_mem_set = 0; | |
1803 | } | |
1804 | ||
1805 | /* Update OLD for the registers used or set. */ | |
916b1701 MM |
1806 | AND_COMPL_REG_SET (old, dead); |
1807 | IOR_REG_SET (old, live); | |
d7429b6a RK |
1808 | |
1809 | if (GET_CODE (insn) == CALL_INSN && final) | |
1810 | { | |
1811 | /* Any regs live at the time of a call instruction | |
1812 | must not go in a register clobbered by calls. | |
1813 | Find all regs now live and record this for them. */ | |
1814 | ||
916b1701 | 1815 | register int *p = regs_sometimes_live; |
d7429b6a RK |
1816 | |
1817 | for (i = 0; i < sometimes_max; i++, p++) | |
916b1701 MM |
1818 | if (REGNO_REG_SET_P (old, *p)) |
1819 | REG_N_CALLS_CROSSED (*p)++; | |
d7429b6a RK |
1820 | } |
1821 | } | |
1822 | ||
1823 | /* On final pass, add any additional sometimes-live regs | |
1824 | into MAXLIVE and REGS_SOMETIMES_LIVE. | |
1825 | Also update counts of how many insns each reg is live at. */ | |
1826 | ||
1827 | if (final) | |
1828 | { | |
916b1701 MM |
1829 | register int regno; |
1830 | register int *p; | |
d7429b6a | 1831 | |
b5835272 RK |
1832 | EXECUTE_IF_AND_COMPL_IN_REG_SET |
1833 | (live, maxlive, 0, regno, | |
1834 | { | |
1835 | regs_sometimes_live[sometimes_max++] = regno; | |
1836 | SET_REGNO_REG_SET (maxlive, regno); | |
1837 | }); | |
d7429b6a | 1838 | |
916b1701 MM |
1839 | p = regs_sometimes_live; |
1840 | for (i = 0; i < sometimes_max; i++) | |
1841 | { | |
1842 | regno = *p++; | |
1843 | if (REGNO_REG_SET_P (old, regno)) | |
1844 | REG_LIVE_LENGTH (regno)++; | |
1845 | } | |
d7429b6a RK |
1846 | } |
1847 | } | |
1848 | flushed: ; | |
1849 | if (insn == first) | |
1850 | break; | |
1851 | } | |
1852 | ||
67f0e213 RK |
1853 | FREE_REG_SET (dead); |
1854 | FREE_REG_SET (live); | |
1855 | if (final) | |
1856 | FREE_REG_SET (maxlive); | |
1857 | ||
d7429b6a RK |
1858 | if (num_scratch > max_scratch) |
1859 | max_scratch = num_scratch; | |
1860 | } | |
1861 | \f | |
1862 | /* Return 1 if X (the body of an insn, or part of it) is just dead stores | |
1863 | (SET expressions whose destinations are registers dead after the insn). | |
1864 | NEEDED is the regset that says which regs are alive after the insn. | |
1865 | ||
1866 | Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. */ | |
1867 | ||
1868 | static int | |
1869 | insn_dead_p (x, needed, call_ok) | |
1870 | rtx x; | |
1871 | regset needed; | |
1872 | int call_ok; | |
1873 | { | |
e5e809f4 JL |
1874 | enum rtx_code code = GET_CODE (x); |
1875 | ||
d7429b6a RK |
1876 | /* If setting something that's a reg or part of one, |
1877 | see if that register's altered value will be live. */ | |
1878 | ||
1879 | if (code == SET) | |
1880 | { | |
e5e809f4 JL |
1881 | rtx r = SET_DEST (x); |
1882 | ||
d7429b6a RK |
1883 | /* A SET that is a subroutine call cannot be dead. */ |
1884 | if (! call_ok && GET_CODE (SET_SRC (x)) == CALL) | |
1885 | return 0; | |
1886 | ||
1887 | #ifdef HAVE_cc0 | |
1888 | if (GET_CODE (r) == CC0) | |
1889 | return ! cc0_live; | |
1890 | #endif | |
1891 | ||
1892 | if (GET_CODE (r) == MEM && last_mem_set && ! MEM_VOLATILE_P (r) | |
1893 | && rtx_equal_p (r, last_mem_set)) | |
1894 | return 1; | |
1895 | ||
e5e809f4 JL |
1896 | while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART |
1897 | || GET_CODE (r) == ZERO_EXTRACT) | |
d7429b6a RK |
1898 | r = SUBREG_REG (r); |
1899 | ||
1900 | if (GET_CODE (r) == REG) | |
1901 | { | |
e5e809f4 | 1902 | int regno = REGNO (r); |
d7429b6a | 1903 | |
d8c8b8e3 | 1904 | /* Don't delete insns to set global regs. */ |
d7429b6a RK |
1905 | if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) |
1906 | /* Make sure insns to set frame pointer aren't deleted. */ | |
1907 | || regno == FRAME_POINTER_REGNUM | |
73a187c1 DE |
1908 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
1909 | || regno == HARD_FRAME_POINTER_REGNUM | |
1910 | #endif | |
d7e4fe8b RS |
1911 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
1912 | /* Make sure insns to set arg pointer are never deleted | |
1913 | (if the arg pointer isn't fixed, there will be a USE for | |
0f41302f | 1914 | it, so we can treat it normally). */ |
d7e4fe8b RS |
1915 | || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
1916 | #endif | |
916b1701 | 1917 | || REGNO_REG_SET_P (needed, regno)) |
d7429b6a RK |
1918 | return 0; |
1919 | ||
1920 | /* If this is a hard register, verify that subsequent words are | |
1921 | not needed. */ | |
1922 | if (regno < FIRST_PSEUDO_REGISTER) | |
1923 | { | |
1924 | int n = HARD_REGNO_NREGS (regno, GET_MODE (r)); | |
1925 | ||
1926 | while (--n > 0) | |
916b1701 | 1927 | if (REGNO_REG_SET_P (needed, regno+n)) |
d7429b6a RK |
1928 | return 0; |
1929 | } | |
1930 | ||
1931 | return 1; | |
1932 | } | |
1933 | } | |
e5e809f4 | 1934 | |
d7429b6a RK |
1935 | /* If performing several activities, |
1936 | insn is dead if each activity is individually dead. | |
1937 | Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE | |
1938 | that's inside a PARALLEL doesn't make the insn worth keeping. */ | |
1939 | else if (code == PARALLEL) | |
1940 | { | |
e5e809f4 JL |
1941 | int i = XVECLEN (x, 0); |
1942 | ||
d7429b6a | 1943 | for (i--; i >= 0; i--) |
e5e809f4 JL |
1944 | if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER |
1945 | && GET_CODE (XVECEXP (x, 0, i)) != USE | |
1946 | && ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok)) | |
1947 | return 0; | |
1948 | ||
d7429b6a RK |
1949 | return 1; |
1950 | } | |
e5e809f4 JL |
1951 | |
1952 | /* A CLOBBER of a pseudo-register that is dead serves no purpose. That | |
1953 | is not necessarily true for hard registers. */ | |
1954 | else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG | |
1955 | && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER | |
1956 | && ! REGNO_REG_SET_P (needed, REGNO (XEXP (x, 0)))) | |
1957 | return 1; | |
1958 | ||
1959 | /* We do not check other CLOBBER or USE here. An insn consisting of just | |
1960 | a CLOBBER or just a USE should not be deleted. */ | |
d7429b6a RK |
1961 | return 0; |
1962 | } | |
1963 | ||
1964 | /* If X is the pattern of the last insn in a libcall, and assuming X is dead, | |
1965 | return 1 if the entire library call is dead. | |
1966 | This is true if X copies a register (hard or pseudo) | |
1967 | and if the hard return reg of the call insn is dead. | |
1968 | (The caller should have tested the destination of X already for death.) | |
1969 | ||
1970 | If this insn doesn't just copy a register, then we don't | |
1971 | have an ordinary libcall. In that case, cse could not have | |
1972 | managed to substitute the source for the dest later on, | |
1973 | so we can assume the libcall is dead. | |
1974 | ||
1975 | NEEDED is the bit vector of pseudoregs live before this insn. | |
1976 | NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */ | |
1977 | ||
1978 | static int | |
1979 | libcall_dead_p (x, needed, note, insn) | |
1980 | rtx x; | |
1981 | regset needed; | |
1982 | rtx note; | |
1983 | rtx insn; | |
1984 | { | |
1985 | register RTX_CODE code = GET_CODE (x); | |
1986 | ||
1987 | if (code == SET) | |
1988 | { | |
1989 | register rtx r = SET_SRC (x); | |
1990 | if (GET_CODE (r) == REG) | |
1991 | { | |
1992 | rtx call = XEXP (note, 0); | |
1993 | register int i; | |
1994 | ||
1995 | /* Find the call insn. */ | |
1996 | while (call != insn && GET_CODE (call) != CALL_INSN) | |
1997 | call = NEXT_INSN (call); | |
1998 | ||
1999 | /* If there is none, do nothing special, | |
2000 | since ordinary death handling can understand these insns. */ | |
2001 | if (call == insn) | |
2002 | return 0; | |
2003 | ||
2004 | /* See if the hard reg holding the value is dead. | |
2005 | If this is a PARALLEL, find the call within it. */ | |
2006 | call = PATTERN (call); | |
2007 | if (GET_CODE (call) == PARALLEL) | |
2008 | { | |
2009 | for (i = XVECLEN (call, 0) - 1; i >= 0; i--) | |
2010 | if (GET_CODE (XVECEXP (call, 0, i)) == SET | |
2011 | && GET_CODE (SET_SRC (XVECEXP (call, 0, i))) == CALL) | |
2012 | break; | |
2013 | ||
761a5bcd JW |
2014 | /* This may be a library call that is returning a value |
2015 | via invisible pointer. Do nothing special, since | |
2016 | ordinary death handling can understand these insns. */ | |
d7429b6a | 2017 | if (i < 0) |
761a5bcd | 2018 | return 0; |
d7429b6a RK |
2019 | |
2020 | call = XVECEXP (call, 0, i); | |
2021 | } | |
2022 | ||
2023 | return insn_dead_p (call, needed, 1); | |
2024 | } | |
2025 | } | |
2026 | return 1; | |
2027 | } | |
2028 | ||
2029 | /* Return 1 if register REGNO was used before it was set. | |
944e5f77 | 2030 | In other words, if it is live at function entry. |
6a45254e RK |
2031 | Don't count global register variables or variables in registers |
2032 | that can be used for function arg passing, though. */ | |
d7429b6a RK |
2033 | |
2034 | int | |
2035 | regno_uninitialized (regno) | |
2036 | int regno; | |
2037 | { | |
b0b7b46a | 2038 | if (n_basic_blocks == 0 |
6a45254e RK |
2039 | || (regno < FIRST_PSEUDO_REGISTER |
2040 | && (global_regs[regno] || FUNCTION_ARG_REGNO_P (regno)))) | |
d7429b6a RK |
2041 | return 0; |
2042 | ||
916b1701 | 2043 | return REGNO_REG_SET_P (basic_block_live_at_start[0], regno); |
d7429b6a RK |
2044 | } |
2045 | ||
2046 | /* 1 if register REGNO was alive at a place where `setjmp' was called | |
2047 | and was set more than once or is an argument. | |
2048 | Such regs may be clobbered by `longjmp'. */ | |
2049 | ||
2050 | int | |
2051 | regno_clobbered_at_setjmp (regno) | |
2052 | int regno; | |
2053 | { | |
2054 | if (n_basic_blocks == 0) | |
2055 | return 0; | |
2056 | ||
b1f21e0a | 2057 | return ((REG_N_SETS (regno) > 1 |
916b1701 MM |
2058 | || REGNO_REG_SET_P (basic_block_live_at_start[0], regno)) |
2059 | && REGNO_REG_SET_P (regs_live_at_setjmp, regno)); | |
d7429b6a RK |
2060 | } |
2061 | \f | |
2062 | /* Process the registers that are set within X. | |
2063 | Their bits are set to 1 in the regset DEAD, | |
2064 | because they are dead prior to this insn. | |
2065 | ||
2066 | If INSN is nonzero, it is the insn being processed | |
2067 | and the fact that it is nonzero implies this is the FINAL pass | |
2068 | in propagate_block. In this case, various info about register | |
2069 | usage is stored, LOG_LINKS fields of insns are set up. */ | |
2070 | ||
d7429b6a RK |
2071 | static void |
2072 | mark_set_regs (needed, dead, x, insn, significant) | |
2073 | regset needed; | |
2074 | regset dead; | |
2075 | rtx x; | |
2076 | rtx insn; | |
2077 | regset significant; | |
2078 | { | |
2079 | register RTX_CODE code = GET_CODE (x); | |
2080 | ||
2081 | if (code == SET || code == CLOBBER) | |
2082 | mark_set_1 (needed, dead, x, insn, significant); | |
2083 | else if (code == PARALLEL) | |
2084 | { | |
2085 | register int i; | |
2086 | for (i = XVECLEN (x, 0) - 1; i >= 0; i--) | |
2087 | { | |
2088 | code = GET_CODE (XVECEXP (x, 0, i)); | |
2089 | if (code == SET || code == CLOBBER) | |
2090 | mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant); | |
2091 | } | |
2092 | } | |
2093 | } | |
2094 | ||
2095 | /* Process a single SET rtx, X. */ | |
2096 | ||
2097 | static void | |
2098 | mark_set_1 (needed, dead, x, insn, significant) | |
2099 | regset needed; | |
2100 | regset dead; | |
2101 | rtx x; | |
2102 | rtx insn; | |
2103 | regset significant; | |
2104 | { | |
2105 | register int regno; | |
2106 | register rtx reg = SET_DEST (x); | |
2107 | ||
2108 | /* Modifying just one hardware register of a multi-reg value | |
2109 | or just a byte field of a register | |
2110 | does not mean the value from before this insn is now dead. | |
2111 | But it does mean liveness of that register at the end of the block | |
2112 | is significant. | |
2113 | ||
2114 | Within mark_set_1, however, we treat it as if the register is | |
2115 | indeed modified. mark_used_regs will, however, also treat this | |
2116 | register as being used. Thus, we treat these insns as setting a | |
2117 | new value for the register as a function of its old value. This | |
2118 | cases LOG_LINKS to be made appropriately and this will help combine. */ | |
2119 | ||
2120 | while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT | |
2121 | || GET_CODE (reg) == SIGN_EXTRACT | |
2122 | || GET_CODE (reg) == STRICT_LOW_PART) | |
2123 | reg = XEXP (reg, 0); | |
2124 | ||
2125 | /* If we are writing into memory or into a register mentioned in the | |
2126 | address of the last thing stored into memory, show we don't know | |
2127 | what the last store was. If we are writing memory, save the address | |
2128 | unless it is volatile. */ | |
2129 | if (GET_CODE (reg) == MEM | |
2130 | || (GET_CODE (reg) == REG | |
2131 | && last_mem_set != 0 && reg_overlap_mentioned_p (reg, last_mem_set))) | |
2132 | last_mem_set = 0; | |
2133 | ||
2134 | if (GET_CODE (reg) == MEM && ! side_effects_p (reg) | |
2135 | /* There are no REG_INC notes for SP, so we can't assume we'll see | |
2136 | everything that invalidates it. To be safe, don't eliminate any | |
2137 | stores though SP; none of them should be redundant anyway. */ | |
2138 | && ! reg_mentioned_p (stack_pointer_rtx, reg)) | |
2139 | last_mem_set = reg; | |
2140 | ||
2141 | if (GET_CODE (reg) == REG | |
2142 | && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM) | |
73a187c1 DE |
2143 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
2144 | && regno != HARD_FRAME_POINTER_REGNUM | |
2145 | #endif | |
d7e4fe8b RS |
2146 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
2147 | && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
2148 | #endif | |
d7429b6a RK |
2149 | && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])) |
2150 | /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */ | |
2151 | { | |
916b1701 MM |
2152 | int some_needed = REGNO_REG_SET_P (needed, regno); |
2153 | int some_not_needed = ! some_needed; | |
d7429b6a RK |
2154 | |
2155 | /* Mark it as a significant register for this basic block. */ | |
2156 | if (significant) | |
916b1701 | 2157 | SET_REGNO_REG_SET (significant, regno); |
d7429b6a | 2158 | |
38e01259 | 2159 | /* Mark it as dead before this insn. */ |
916b1701 | 2160 | SET_REGNO_REG_SET (dead, regno); |
d7429b6a RK |
2161 | |
2162 | /* A hard reg in a wide mode may really be multiple registers. | |
2163 | If so, mark all of them just like the first. */ | |
2164 | if (regno < FIRST_PSEUDO_REGISTER) | |
2165 | { | |
2166 | int n; | |
2167 | ||
2168 | /* Nothing below is needed for the stack pointer; get out asap. | |
2169 | Eg, log links aren't needed, since combine won't use them. */ | |
2170 | if (regno == STACK_POINTER_REGNUM) | |
2171 | return; | |
2172 | ||
2173 | n = HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
2174 | while (--n > 0) | |
2175 | { | |
916b1701 MM |
2176 | int regno_n = regno + n; |
2177 | int needed_regno = REGNO_REG_SET_P (needed, regno_n); | |
d7429b6a | 2178 | if (significant) |
916b1701 | 2179 | SET_REGNO_REG_SET (significant, regno_n); |
cb9e8ad1 | 2180 | |
916b1701 MM |
2181 | SET_REGNO_REG_SET (dead, regno_n); |
2182 | some_needed |= needed_regno; | |
2183 | some_not_needed |= ! needed_regno; | |
d7429b6a RK |
2184 | } |
2185 | } | |
2186 | /* Additional data to record if this is the final pass. */ | |
2187 | if (insn) | |
2188 | { | |
2189 | register rtx y = reg_next_use[regno]; | |
2190 | register int blocknum = BLOCK_NUM (insn); | |
2191 | ||
2192 | /* If this is a hard reg, record this function uses the reg. */ | |
2193 | ||
2194 | if (regno < FIRST_PSEUDO_REGISTER) | |
2195 | { | |
2196 | register int i; | |
2197 | int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
2198 | ||
2199 | for (i = regno; i < endregno; i++) | |
2200 | { | |
93514916 JW |
2201 | /* The next use is no longer "next", since a store |
2202 | intervenes. */ | |
2203 | reg_next_use[i] = 0; | |
2204 | ||
d7429b6a | 2205 | regs_ever_live[i] = 1; |
b1f21e0a | 2206 | REG_N_SETS (i)++; |
d7429b6a RK |
2207 | } |
2208 | } | |
2209 | else | |
2210 | { | |
93514916 JW |
2211 | /* The next use is no longer "next", since a store |
2212 | intervenes. */ | |
2213 | reg_next_use[regno] = 0; | |
2214 | ||
d7429b6a RK |
2215 | /* Keep track of which basic blocks each reg appears in. */ |
2216 | ||
b1f21e0a MM |
2217 | if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
2218 | REG_BASIC_BLOCK (regno) = blocknum; | |
2219 | else if (REG_BASIC_BLOCK (regno) != blocknum) | |
2220 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; | |
d7429b6a RK |
2221 | |
2222 | /* Count (weighted) references, stores, etc. This counts a | |
2223 | register twice if it is modified, but that is correct. */ | |
b1f21e0a | 2224 | REG_N_SETS (regno)++; |
d7429b6a | 2225 | |
b1f21e0a | 2226 | REG_N_REFS (regno) += loop_depth; |
d7429b6a RK |
2227 | |
2228 | /* The insns where a reg is live are normally counted | |
2229 | elsewhere, but we want the count to include the insn | |
2230 | where the reg is set, and the normal counting mechanism | |
2231 | would not count it. */ | |
b1f21e0a | 2232 | REG_LIVE_LENGTH (regno)++; |
d7429b6a RK |
2233 | } |
2234 | ||
cb9e8ad1 | 2235 | if (! some_not_needed) |
d7429b6a RK |
2236 | { |
2237 | /* Make a logical link from the next following insn | |
2238 | that uses this register, back to this insn. | |
2239 | The following insns have already been processed. | |
2240 | ||
2241 | We don't build a LOG_LINK for hard registers containing | |
2242 | in ASM_OPERANDs. If these registers get replaced, | |
2243 | we might wind up changing the semantics of the insn, | |
2244 | even if reload can make what appear to be valid assignments | |
2245 | later. */ | |
2246 | if (y && (BLOCK_NUM (y) == blocknum) | |
2247 | && (regno >= FIRST_PSEUDO_REGISTER | |
2248 | || asm_noperands (PATTERN (y)) < 0)) | |
2249 | LOG_LINKS (y) | |
38a448ca | 2250 | = gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y)); |
d7429b6a RK |
2251 | } |
2252 | else if (! some_needed) | |
2253 | { | |
2254 | /* Note that dead stores have already been deleted when possible | |
2255 | If we get here, we have found a dead store that cannot | |
2256 | be eliminated (because the same insn does something useful). | |
2257 | Indicate this by marking the reg being set as dying here. */ | |
2258 | REG_NOTES (insn) | |
38a448ca | 2259 | = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
b1f21e0a | 2260 | REG_N_DEATHS (REGNO (reg))++; |
d7429b6a RK |
2261 | } |
2262 | else | |
2263 | { | |
2264 | /* This is a case where we have a multi-word hard register | |
2265 | and some, but not all, of the words of the register are | |
2266 | needed in subsequent insns. Write REG_UNUSED notes | |
2267 | for those parts that were not needed. This case should | |
2268 | be rare. */ | |
2269 | ||
2270 | int i; | |
2271 | ||
2272 | for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1; | |
2273 | i >= 0; i--) | |
916b1701 | 2274 | if (!REGNO_REG_SET_P (needed, regno + i)) |
d7429b6a | 2275 | REG_NOTES (insn) |
38a448ca RH |
2276 | = gen_rtx_EXPR_LIST (REG_UNUSED, |
2277 | gen_rtx_REG (reg_raw_mode[regno + i], | |
2278 | regno + i), | |
2279 | REG_NOTES (insn)); | |
d7429b6a RK |
2280 | } |
2281 | } | |
2282 | } | |
8244fc4f RS |
2283 | else if (GET_CODE (reg) == REG) |
2284 | reg_next_use[regno] = 0; | |
d7429b6a RK |
2285 | |
2286 | /* If this is the last pass and this is a SCRATCH, show it will be dying | |
2287 | here and count it. */ | |
2288 | else if (GET_CODE (reg) == SCRATCH && insn != 0) | |
2289 | { | |
2290 | REG_NOTES (insn) | |
38a448ca | 2291 | = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
d7429b6a RK |
2292 | num_scratch++; |
2293 | } | |
2294 | } | |
2295 | \f | |
2296 | #ifdef AUTO_INC_DEC | |
2297 | ||
2298 | /* X is a MEM found in INSN. See if we can convert it into an auto-increment | |
2299 | reference. */ | |
2300 | ||
2301 | static void | |
2302 | find_auto_inc (needed, x, insn) | |
2303 | regset needed; | |
2304 | rtx x; | |
2305 | rtx insn; | |
2306 | { | |
2307 | rtx addr = XEXP (x, 0); | |
e658434c | 2308 | HOST_WIDE_INT offset = 0; |
05ed5d57 | 2309 | rtx set; |
d7429b6a RK |
2310 | |
2311 | /* Here we detect use of an index register which might be good for | |
2312 | postincrement, postdecrement, preincrement, or predecrement. */ | |
2313 | ||
2314 | if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT) | |
2315 | offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0); | |
2316 | ||
2317 | if (GET_CODE (addr) == REG) | |
2318 | { | |
2319 | register rtx y; | |
2320 | register int size = GET_MODE_SIZE (GET_MODE (x)); | |
2321 | rtx use; | |
2322 | rtx incr; | |
2323 | int regno = REGNO (addr); | |
2324 | ||
2325 | /* Is the next use an increment that might make auto-increment? */ | |
05ed5d57 RK |
2326 | if ((incr = reg_next_use[regno]) != 0 |
2327 | && (set = single_set (incr)) != 0 | |
2328 | && GET_CODE (set) == SET | |
d7429b6a RK |
2329 | && BLOCK_NUM (incr) == BLOCK_NUM (insn) |
2330 | /* Can't add side effects to jumps; if reg is spilled and | |
2331 | reloaded, there's no way to store back the altered value. */ | |
2332 | && GET_CODE (insn) != JUMP_INSN | |
05ed5d57 | 2333 | && (y = SET_SRC (set), GET_CODE (y) == PLUS) |
d7429b6a RK |
2334 | && XEXP (y, 0) == addr |
2335 | && GET_CODE (XEXP (y, 1)) == CONST_INT | |
2336 | && (0 | |
2337 | #ifdef HAVE_POST_INCREMENT | |
2338 | || (INTVAL (XEXP (y, 1)) == size && offset == 0) | |
2339 | #endif | |
2340 | #ifdef HAVE_POST_DECREMENT | |
2341 | || (INTVAL (XEXP (y, 1)) == - size && offset == 0) | |
2342 | #endif | |
2343 | #ifdef HAVE_PRE_INCREMENT | |
2344 | || (INTVAL (XEXP (y, 1)) == size && offset == size) | |
2345 | #endif | |
2346 | #ifdef HAVE_PRE_DECREMENT | |
2347 | || (INTVAL (XEXP (y, 1)) == - size && offset == - size) | |
2348 | #endif | |
2349 | ) | |
2350 | /* Make sure this reg appears only once in this insn. */ | |
2351 | && (use = find_use_as_address (PATTERN (insn), addr, offset), | |
2352 | use != 0 && use != (rtx) 1)) | |
2353 | { | |
05ed5d57 | 2354 | rtx q = SET_DEST (set); |
7280c2a4 RK |
2355 | enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size |
2356 | ? (offset ? PRE_INC : POST_INC) | |
2357 | : (offset ? PRE_DEC : POST_DEC)); | |
d7429b6a RK |
2358 | |
2359 | if (dead_or_set_p (incr, addr)) | |
7280c2a4 RK |
2360 | { |
2361 | /* This is the simple case. Try to make the auto-inc. If | |
2362 | we can't, we are done. Otherwise, we will do any | |
2363 | needed updates below. */ | |
2364 | if (! validate_change (insn, &XEXP (x, 0), | |
38a448ca | 2365 | gen_rtx_fmt_e (inc_code, Pmode, addr), |
7280c2a4 RK |
2366 | 0)) |
2367 | return; | |
2368 | } | |
5175ad37 DE |
2369 | else if (GET_CODE (q) == REG |
2370 | /* PREV_INSN used here to check the semi-open interval | |
2371 | [insn,incr). */ | |
b24884cd JL |
2372 | && ! reg_used_between_p (q, PREV_INSN (insn), incr) |
2373 | /* We must also check for sets of q as q may be | |
2374 | a call clobbered hard register and there may | |
2375 | be a call between PREV_INSN (insn) and incr. */ | |
2376 | && ! reg_set_between_p (q, PREV_INSN (insn), incr)) | |
d7429b6a | 2377 | { |
5175ad37 | 2378 | /* We have *p followed sometime later by q = p+size. |
d7429b6a | 2379 | Both p and q must be live afterward, |
5175ad37 | 2380 | and q is not used between INSN and it's assignment. |
d7429b6a RK |
2381 | Change it to q = p, ...*q..., q = q+size. |
2382 | Then fall into the usual case. */ | |
2383 | rtx insns, temp; | |
2384 | ||
2385 | start_sequence (); | |
2386 | emit_move_insn (q, addr); | |
2387 | insns = get_insns (); | |
2388 | end_sequence (); | |
2389 | ||
2390 | /* If anything in INSNS have UID's that don't fit within the | |
2391 | extra space we allocate earlier, we can't make this auto-inc. | |
2392 | This should never happen. */ | |
2393 | for (temp = insns; temp; temp = NEXT_INSN (temp)) | |
2394 | { | |
2395 | if (INSN_UID (temp) > max_uid_for_flow) | |
2396 | return; | |
2397 | BLOCK_NUM (temp) = BLOCK_NUM (insn); | |
2398 | } | |
2399 | ||
7280c2a4 RK |
2400 | /* If we can't make the auto-inc, or can't make the |
2401 | replacement into Y, exit. There's no point in making | |
2402 | the change below if we can't do the auto-inc and doing | |
2403 | so is not correct in the pre-inc case. */ | |
2404 | ||
2405 | validate_change (insn, &XEXP (x, 0), | |
38a448ca | 2406 | gen_rtx_fmt_e (inc_code, Pmode, q), |
7280c2a4 RK |
2407 | 1); |
2408 | validate_change (incr, &XEXP (y, 0), q, 1); | |
2409 | if (! apply_change_group ()) | |
2410 | return; | |
2411 | ||
2412 | /* We now know we'll be doing this change, so emit the | |
2413 | new insn(s) and do the updates. */ | |
d7429b6a | 2414 | emit_insns_before (insns, insn); |
e8b641a1 RK |
2415 | |
2416 | if (basic_block_head[BLOCK_NUM (insn)] == insn) | |
2417 | basic_block_head[BLOCK_NUM (insn)] = insns; | |
2418 | ||
d7429b6a RK |
2419 | /* INCR will become a NOTE and INSN won't contain a |
2420 | use of ADDR. If a use of ADDR was just placed in | |
2421 | the insn before INSN, make that the next use. | |
2422 | Otherwise, invalidate it. */ | |
2423 | if (GET_CODE (PREV_INSN (insn)) == INSN | |
2424 | && GET_CODE (PATTERN (PREV_INSN (insn))) == SET | |
2425 | && SET_SRC (PATTERN (PREV_INSN (insn))) == addr) | |
2426 | reg_next_use[regno] = PREV_INSN (insn); | |
2427 | else | |
2428 | reg_next_use[regno] = 0; | |
2429 | ||
2430 | addr = q; | |
2431 | regno = REGNO (q); | |
d7429b6a RK |
2432 | |
2433 | /* REGNO is now used in INCR which is below INSN, but | |
2434 | it previously wasn't live here. If we don't mark | |
2435 | it as needed, we'll put a REG_DEAD note for it | |
2436 | on this insn, which is incorrect. */ | |
916b1701 | 2437 | SET_REGNO_REG_SET (needed, regno); |
d7429b6a RK |
2438 | |
2439 | /* If there are any calls between INSN and INCR, show | |
2440 | that REGNO now crosses them. */ | |
2441 | for (temp = insn; temp != incr; temp = NEXT_INSN (temp)) | |
2442 | if (GET_CODE (temp) == CALL_INSN) | |
b1f21e0a | 2443 | REG_N_CALLS_CROSSED (regno)++; |
d7429b6a | 2444 | } |
02df8aba RK |
2445 | else |
2446 | return; | |
d7429b6a | 2447 | |
7280c2a4 RK |
2448 | /* If we haven't returned, it means we were able to make the |
2449 | auto-inc, so update the status. First, record that this insn | |
2450 | has an implicit side effect. */ | |
2451 | ||
2452 | REG_NOTES (insn) | |
38a448ca | 2453 | = gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn)); |
7280c2a4 RK |
2454 | |
2455 | /* Modify the old increment-insn to simply copy | |
2456 | the already-incremented value of our register. */ | |
2457 | if (! validate_change (incr, &SET_SRC (set), addr, 0)) | |
2458 | abort (); | |
2459 | ||
2460 | /* If that makes it a no-op (copying the register into itself) delete | |
2461 | it so it won't appear to be a "use" and a "set" of this | |
2462 | register. */ | |
2463 | if (SET_DEST (set) == addr) | |
d7429b6a | 2464 | { |
7280c2a4 RK |
2465 | PUT_CODE (incr, NOTE); |
2466 | NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED; | |
2467 | NOTE_SOURCE_FILE (incr) = 0; | |
2468 | } | |
d7429b6a | 2469 | |
7280c2a4 RK |
2470 | if (regno >= FIRST_PSEUDO_REGISTER) |
2471 | { | |
2472 | /* Count an extra reference to the reg. When a reg is | |
2473 | incremented, spilling it is worse, so we want to make | |
2474 | that less likely. */ | |
b1f21e0a | 2475 | REG_N_REFS (regno) += loop_depth; |
7280c2a4 RK |
2476 | |
2477 | /* Count the increment as a setting of the register, | |
2478 | even though it isn't a SET in rtl. */ | |
b1f21e0a | 2479 | REG_N_SETS (regno)++; |
d7429b6a RK |
2480 | } |
2481 | } | |
2482 | } | |
2483 | } | |
2484 | #endif /* AUTO_INC_DEC */ | |
2485 | \f | |
2486 | /* Scan expression X and store a 1-bit in LIVE for each reg it uses. | |
2487 | This is done assuming the registers needed from X | |
2488 | are those that have 1-bits in NEEDED. | |
2489 | ||
2490 | On the final pass, FINAL is 1. This means try for autoincrement | |
2491 | and count the uses and deaths of each pseudo-reg. | |
2492 | ||
2493 | INSN is the containing instruction. If INSN is dead, this function is not | |
2494 | called. */ | |
2495 | ||
2496 | static void | |
2497 | mark_used_regs (needed, live, x, final, insn) | |
2498 | regset needed; | |
2499 | regset live; | |
2500 | rtx x; | |
d7429b6a | 2501 | int final; |
e658434c | 2502 | rtx insn; |
d7429b6a RK |
2503 | { |
2504 | register RTX_CODE code; | |
2505 | register int regno; | |
2506 | int i; | |
2507 | ||
2508 | retry: | |
2509 | code = GET_CODE (x); | |
2510 | switch (code) | |
2511 | { | |
2512 | case LABEL_REF: | |
2513 | case SYMBOL_REF: | |
2514 | case CONST_INT: | |
2515 | case CONST: | |
2516 | case CONST_DOUBLE: | |
2517 | case PC: | |
d7429b6a RK |
2518 | case ADDR_VEC: |
2519 | case ADDR_DIFF_VEC: | |
2520 | case ASM_INPUT: | |
2521 | return; | |
2522 | ||
2523 | #ifdef HAVE_cc0 | |
2524 | case CC0: | |
2525 | cc0_live = 1; | |
2526 | return; | |
2527 | #endif | |
2528 | ||
2f1553a4 RK |
2529 | case CLOBBER: |
2530 | /* If we are clobbering a MEM, mark any registers inside the address | |
2531 | as being used. */ | |
2532 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
2533 | mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn); | |
2534 | return; | |
2535 | ||
d7429b6a | 2536 | case MEM: |
7eb136d6 MM |
2537 | /* Invalidate the data for the last MEM stored, but only if MEM is |
2538 | something that can be stored into. */ | |
2539 | if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF | |
2540 | && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) | |
2541 | ; /* needn't clear last_mem_set */ | |
2542 | else | |
2543 | last_mem_set = 0; | |
d7429b6a RK |
2544 | |
2545 | #ifdef AUTO_INC_DEC | |
2546 | if (final) | |
2547 | find_auto_inc (needed, x, insn); | |
2548 | #endif | |
2549 | break; | |
2550 | ||
80f8f04a RK |
2551 | case SUBREG: |
2552 | if (GET_CODE (SUBREG_REG (x)) == REG | |
2553 | && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER | |
2554 | && (GET_MODE_SIZE (GET_MODE (x)) | |
88285acf | 2555 | != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))) |
b1f21e0a | 2556 | REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1; |
80f8f04a RK |
2557 | |
2558 | /* While we're here, optimize this case. */ | |
2559 | x = SUBREG_REG (x); | |
2560 | ||
e100a3bb | 2561 | /* In case the SUBREG is not of a register, don't optimize */ |
ce79abf3 | 2562 | if (GET_CODE (x) != REG) |
e100a3bb MM |
2563 | { |
2564 | mark_used_regs (needed, live, x, final, insn); | |
2565 | return; | |
2566 | } | |
ce79abf3 | 2567 | |
0f41302f | 2568 | /* ... fall through ... */ |
80f8f04a | 2569 | |
d7429b6a RK |
2570 | case REG: |
2571 | /* See a register other than being set | |
2572 | => mark it as needed. */ | |
2573 | ||
2574 | regno = REGNO (x); | |
2575 | { | |
67f0e213 RK |
2576 | int some_needed = REGNO_REG_SET_P (needed, regno); |
2577 | int some_not_needed = ! some_needed; | |
d7429b6a | 2578 | |
916b1701 | 2579 | SET_REGNO_REG_SET (live, regno); |
cb9e8ad1 | 2580 | |
d7429b6a RK |
2581 | /* A hard reg in a wide mode may really be multiple registers. |
2582 | If so, mark all of them just like the first. */ | |
2583 | if (regno < FIRST_PSEUDO_REGISTER) | |
2584 | { | |
2585 | int n; | |
2586 | ||
d7e4fe8b | 2587 | /* For stack ptr or fixed arg pointer, |
d7429b6a RK |
2588 | nothing below can be necessary, so waste no more time. */ |
2589 | if (regno == STACK_POINTER_REGNUM | |
73a187c1 DE |
2590 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
2591 | || regno == HARD_FRAME_POINTER_REGNUM | |
2592 | #endif | |
d7e4fe8b RS |
2593 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
2594 | || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
2595 | #endif | |
d7429b6a RK |
2596 | || regno == FRAME_POINTER_REGNUM) |
2597 | { | |
2598 | /* If this is a register we are going to try to eliminate, | |
2599 | don't mark it live here. If we are successful in | |
2600 | eliminating it, it need not be live unless it is used for | |
2601 | pseudos, in which case it will have been set live when | |
2602 | it was allocated to the pseudos. If the register will not | |
2603 | be eliminated, reload will set it live at that point. */ | |
2604 | ||
2605 | if (! TEST_HARD_REG_BIT (elim_reg_set, regno)) | |
2606 | regs_ever_live[regno] = 1; | |
2607 | return; | |
2608 | } | |
2609 | /* No death notes for global register variables; | |
2610 | their values are live after this function exits. */ | |
2611 | if (global_regs[regno]) | |
d8c8b8e3 RS |
2612 | { |
2613 | if (final) | |
2614 | reg_next_use[regno] = insn; | |
2615 | return; | |
2616 | } | |
d7429b6a RK |
2617 | |
2618 | n = HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
2619 | while (--n > 0) | |
2620 | { | |
916b1701 MM |
2621 | int regno_n = regno + n; |
2622 | int needed_regno = REGNO_REG_SET_P (needed, regno_n); | |
cb9e8ad1 | 2623 | |
916b1701 MM |
2624 | SET_REGNO_REG_SET (live, regno_n); |
2625 | some_needed |= needed_regno; | |
931c6c7a | 2626 | some_not_needed |= ! needed_regno; |
d7429b6a RK |
2627 | } |
2628 | } | |
2629 | if (final) | |
2630 | { | |
2631 | /* Record where each reg is used, so when the reg | |
2632 | is set we know the next insn that uses it. */ | |
2633 | ||
2634 | reg_next_use[regno] = insn; | |
2635 | ||
2636 | if (regno < FIRST_PSEUDO_REGISTER) | |
2637 | { | |
2638 | /* If a hard reg is being used, | |
2639 | record that this function does use it. */ | |
2640 | ||
2641 | i = HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
2642 | if (i == 0) | |
2643 | i = 1; | |
2644 | do | |
2645 | regs_ever_live[regno + --i] = 1; | |
2646 | while (i > 0); | |
2647 | } | |
2648 | else | |
2649 | { | |
2650 | /* Keep track of which basic block each reg appears in. */ | |
2651 | ||
2652 | register int blocknum = BLOCK_NUM (insn); | |
2653 | ||
b1f21e0a MM |
2654 | if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
2655 | REG_BASIC_BLOCK (regno) = blocknum; | |
2656 | else if (REG_BASIC_BLOCK (regno) != blocknum) | |
2657 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; | |
d7429b6a RK |
2658 | |
2659 | /* Count (weighted) number of uses of each reg. */ | |
2660 | ||
b1f21e0a | 2661 | REG_N_REFS (regno) += loop_depth; |
d7429b6a RK |
2662 | } |
2663 | ||
2664 | /* Record and count the insns in which a reg dies. | |
2665 | If it is used in this insn and was dead below the insn | |
2666 | then it dies in this insn. If it was set in this insn, | |
2667 | we do not make a REG_DEAD note; likewise if we already | |
2668 | made such a note. */ | |
2669 | ||
cb9e8ad1 | 2670 | if (some_not_needed |
d7429b6a RK |
2671 | && ! dead_or_set_p (insn, x) |
2672 | #if 0 | |
2673 | && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
2674 | #endif | |
2675 | ) | |
2676 | { | |
ab28041e JW |
2677 | /* Check for the case where the register dying partially |
2678 | overlaps the register set by this insn. */ | |
2679 | if (regno < FIRST_PSEUDO_REGISTER | |
2680 | && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1) | |
2681 | { | |
480eac3b | 2682 | int n = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
ab28041e JW |
2683 | while (--n >= 0) |
2684 | some_needed |= dead_or_set_regno_p (insn, regno + n); | |
2685 | } | |
2686 | ||
d7429b6a RK |
2687 | /* If none of the words in X is needed, make a REG_DEAD |
2688 | note. Otherwise, we must make partial REG_DEAD notes. */ | |
2689 | if (! some_needed) | |
2690 | { | |
2691 | REG_NOTES (insn) | |
38a448ca | 2692 | = gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn)); |
b1f21e0a | 2693 | REG_N_DEATHS (regno)++; |
d7429b6a RK |
2694 | } |
2695 | else | |
2696 | { | |
2697 | int i; | |
2698 | ||
2699 | /* Don't make a REG_DEAD note for a part of a register | |
2700 | that is set in the insn. */ | |
2701 | ||
2702 | for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1; | |
2703 | i >= 0; i--) | |
916b1701 | 2704 | if (!REGNO_REG_SET_P (needed, regno + i) |
d7429b6a RK |
2705 | && ! dead_or_set_regno_p (insn, regno + i)) |
2706 | REG_NOTES (insn) | |
38a448ca RH |
2707 | = gen_rtx_EXPR_LIST (REG_DEAD, |
2708 | gen_rtx_REG (reg_raw_mode[regno + i], | |
2709 | regno + i), | |
2710 | REG_NOTES (insn)); | |
d7429b6a RK |
2711 | } |
2712 | } | |
2713 | } | |
2714 | } | |
2715 | return; | |
2716 | ||
2717 | case SET: | |
2718 | { | |
2719 | register rtx testreg = SET_DEST (x); | |
2720 | int mark_dest = 0; | |
2721 | ||
2722 | /* If storing into MEM, don't show it as being used. But do | |
2723 | show the address as being used. */ | |
2724 | if (GET_CODE (testreg) == MEM) | |
2725 | { | |
2726 | #ifdef AUTO_INC_DEC | |
2727 | if (final) | |
2728 | find_auto_inc (needed, testreg, insn); | |
2729 | #endif | |
2730 | mark_used_regs (needed, live, XEXP (testreg, 0), final, insn); | |
2731 | mark_used_regs (needed, live, SET_SRC (x), final, insn); | |
2732 | return; | |
2733 | } | |
2734 | ||
2735 | /* Storing in STRICT_LOW_PART is like storing in a reg | |
2736 | in that this SET might be dead, so ignore it in TESTREG. | |
2737 | but in some other ways it is like using the reg. | |
2738 | ||
2739 | Storing in a SUBREG or a bit field is like storing the entire | |
2740 | register in that if the register's value is not used | |
2741 | then this SET is not needed. */ | |
2742 | while (GET_CODE (testreg) == STRICT_LOW_PART | |
2743 | || GET_CODE (testreg) == ZERO_EXTRACT | |
2744 | || GET_CODE (testreg) == SIGN_EXTRACT | |
2745 | || GET_CODE (testreg) == SUBREG) | |
2746 | { | |
88285acf RK |
2747 | if (GET_CODE (testreg) == SUBREG |
2748 | && GET_CODE (SUBREG_REG (testreg)) == REG | |
2749 | && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER | |
2750 | && (GET_MODE_SIZE (GET_MODE (testreg)) | |
2751 | != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg))))) | |
b1f21e0a | 2752 | REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1; |
88285acf | 2753 | |
d7429b6a RK |
2754 | /* Modifying a single register in an alternate mode |
2755 | does not use any of the old value. But these other | |
2756 | ways of storing in a register do use the old value. */ | |
2757 | if (GET_CODE (testreg) == SUBREG | |
2758 | && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg))) | |
2759 | ; | |
2760 | else | |
2761 | mark_dest = 1; | |
2762 | ||
2763 | testreg = XEXP (testreg, 0); | |
2764 | } | |
2765 | ||
2766 | /* If this is a store into a register, | |
2767 | recursively scan the value being stored. */ | |
2768 | ||
2769 | if (GET_CODE (testreg) == REG | |
2770 | && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM) | |
73a187c1 DE |
2771 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
2772 | && regno != HARD_FRAME_POINTER_REGNUM | |
2773 | #endif | |
d7e4fe8b RS |
2774 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
2775 | && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
2776 | #endif | |
d8c8b8e3 RS |
2777 | ) |
2778 | /* We used to exclude global_regs here, but that seems wrong. | |
2779 | Storing in them is like storing in mem. */ | |
d7429b6a RK |
2780 | { |
2781 | mark_used_regs (needed, live, SET_SRC (x), final, insn); | |
2782 | if (mark_dest) | |
2783 | mark_used_regs (needed, live, SET_DEST (x), final, insn); | |
2784 | return; | |
2785 | } | |
2786 | } | |
2787 | break; | |
2788 | ||
2789 | case RETURN: | |
2790 | /* If exiting needs the right stack value, consider this insn as | |
2791 | using the stack pointer. In any event, consider it as using | |
632c9d9e | 2792 | all global registers and all registers used by return. */ |
d7429b6a RK |
2793 | |
2794 | #ifdef EXIT_IGNORE_STACK | |
2795 | if (! EXIT_IGNORE_STACK | |
0200b5ed JL |
2796 | || (! FRAME_POINTER_REQUIRED |
2797 | && ! current_function_calls_alloca | |
2798 | && flag_omit_frame_pointer)) | |
d7429b6a | 2799 | #endif |
916b1701 | 2800 | SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
d7429b6a RK |
2801 | |
2802 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
632c9d9e MS |
2803 | if (global_regs[i] |
2804 | #ifdef EPILOGUE_USES | |
2805 | || EPILOGUE_USES (i) | |
2806 | #endif | |
2807 | ) | |
916b1701 | 2808 | SET_REGNO_REG_SET (live, i); |
d7429b6a | 2809 | break; |
e9a25f70 JL |
2810 | |
2811 | default: | |
2812 | break; | |
d7429b6a RK |
2813 | } |
2814 | ||
2815 | /* Recursively scan the operands of this expression. */ | |
2816 | ||
2817 | { | |
2818 | register char *fmt = GET_RTX_FORMAT (code); | |
2819 | register int i; | |
2820 | ||
2821 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
2822 | { | |
2823 | if (fmt[i] == 'e') | |
2824 | { | |
2825 | /* Tail recursive case: save a function call level. */ | |
2826 | if (i == 0) | |
2827 | { | |
2828 | x = XEXP (x, 0); | |
2829 | goto retry; | |
2830 | } | |
2831 | mark_used_regs (needed, live, XEXP (x, i), final, insn); | |
2832 | } | |
2833 | else if (fmt[i] == 'E') | |
2834 | { | |
2835 | register int j; | |
2836 | for (j = 0; j < XVECLEN (x, i); j++) | |
2837 | mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn); | |
2838 | } | |
2839 | } | |
2840 | } | |
2841 | } | |
2842 | \f | |
2843 | #ifdef AUTO_INC_DEC | |
2844 | ||
2845 | static int | |
2846 | try_pre_increment_1 (insn) | |
2847 | rtx insn; | |
2848 | { | |
2849 | /* Find the next use of this reg. If in same basic block, | |
2850 | make it do pre-increment or pre-decrement if appropriate. */ | |
956d6950 | 2851 | rtx x = single_set (insn); |
5f4f0e22 | 2852 | HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1) |
d7429b6a RK |
2853 | * INTVAL (XEXP (SET_SRC (x), 1))); |
2854 | int regno = REGNO (SET_DEST (x)); | |
2855 | rtx y = reg_next_use[regno]; | |
2856 | if (y != 0 | |
2857 | && BLOCK_NUM (y) == BLOCK_NUM (insn) | |
89861c38 | 2858 | /* Don't do this if the reg dies, or gets set in y; a standard addressing |
0f41302f | 2859 | mode would be better. */ |
89861c38 | 2860 | && ! dead_or_set_p (y, SET_DEST (x)) |
956d6950 | 2861 | && try_pre_increment (y, SET_DEST (x), amount)) |
d7429b6a RK |
2862 | { |
2863 | /* We have found a suitable auto-increment | |
2864 | and already changed insn Y to do it. | |
2865 | So flush this increment-instruction. */ | |
2866 | PUT_CODE (insn, NOTE); | |
2867 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
2868 | NOTE_SOURCE_FILE (insn) = 0; | |
2869 | /* Count a reference to this reg for the increment | |
2870 | insn we are deleting. When a reg is incremented. | |
2871 | spilling it is worse, so we want to make that | |
2872 | less likely. */ | |
2873 | if (regno >= FIRST_PSEUDO_REGISTER) | |
2874 | { | |
b1f21e0a MM |
2875 | REG_N_REFS (regno) += loop_depth; |
2876 | REG_N_SETS (regno)++; | |
d7429b6a RK |
2877 | } |
2878 | return 1; | |
2879 | } | |
2880 | return 0; | |
2881 | } | |
2882 | ||
2883 | /* Try to change INSN so that it does pre-increment or pre-decrement | |
2884 | addressing on register REG in order to add AMOUNT to REG. | |
2885 | AMOUNT is negative for pre-decrement. | |
2886 | Returns 1 if the change could be made. | |
2887 | This checks all about the validity of the result of modifying INSN. */ | |
2888 | ||
2889 | static int | |
2890 | try_pre_increment (insn, reg, amount) | |
2891 | rtx insn, reg; | |
5f4f0e22 | 2892 | HOST_WIDE_INT amount; |
d7429b6a RK |
2893 | { |
2894 | register rtx use; | |
2895 | ||
2896 | /* Nonzero if we can try to make a pre-increment or pre-decrement. | |
2897 | For example, addl $4,r1; movl (r1),... can become movl +(r1),... */ | |
2898 | int pre_ok = 0; | |
2899 | /* Nonzero if we can try to make a post-increment or post-decrement. | |
2900 | For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,... | |
2901 | It is possible for both PRE_OK and POST_OK to be nonzero if the machine | |
2902 | supports both pre-inc and post-inc, or both pre-dec and post-dec. */ | |
2903 | int post_ok = 0; | |
2904 | ||
2905 | /* Nonzero if the opportunity actually requires post-inc or post-dec. */ | |
2906 | int do_post = 0; | |
2907 | ||
2908 | /* From the sign of increment, see which possibilities are conceivable | |
2909 | on this target machine. */ | |
2910 | #ifdef HAVE_PRE_INCREMENT | |
2911 | if (amount > 0) | |
2912 | pre_ok = 1; | |
2913 | #endif | |
2914 | #ifdef HAVE_POST_INCREMENT | |
2915 | if (amount > 0) | |
2916 | post_ok = 1; | |
2917 | #endif | |
2918 | ||
2919 | #ifdef HAVE_PRE_DECREMENT | |
2920 | if (amount < 0) | |
2921 | pre_ok = 1; | |
2922 | #endif | |
2923 | #ifdef HAVE_POST_DECREMENT | |
2924 | if (amount < 0) | |
2925 | post_ok = 1; | |
2926 | #endif | |
2927 | ||
2928 | if (! (pre_ok || post_ok)) | |
2929 | return 0; | |
2930 | ||
2931 | /* It is not safe to add a side effect to a jump insn | |
2932 | because if the incremented register is spilled and must be reloaded | |
2933 | there would be no way to store the incremented value back in memory. */ | |
2934 | ||
2935 | if (GET_CODE (insn) == JUMP_INSN) | |
2936 | return 0; | |
2937 | ||
2938 | use = 0; | |
2939 | if (pre_ok) | |
2940 | use = find_use_as_address (PATTERN (insn), reg, 0); | |
2941 | if (post_ok && (use == 0 || use == (rtx) 1)) | |
2942 | { | |
2943 | use = find_use_as_address (PATTERN (insn), reg, -amount); | |
2944 | do_post = 1; | |
2945 | } | |
2946 | ||
2947 | if (use == 0 || use == (rtx) 1) | |
2948 | return 0; | |
2949 | ||
2950 | if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount)) | |
2951 | return 0; | |
2952 | ||
a0fbc3a9 SC |
2953 | /* See if this combination of instruction and addressing mode exists. */ |
2954 | if (! validate_change (insn, &XEXP (use, 0), | |
38a448ca RH |
2955 | gen_rtx_fmt_e (amount > 0 |
2956 | ? (do_post ? POST_INC : PRE_INC) | |
2957 | : (do_post ? POST_DEC : PRE_DEC), | |
2958 | Pmode, reg), 0)) | |
a0fbc3a9 | 2959 | return 0; |
d7429b6a RK |
2960 | |
2961 | /* Record that this insn now has an implicit side effect on X. */ | |
38a448ca | 2962 | REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn)); |
d7429b6a RK |
2963 | return 1; |
2964 | } | |
2965 | ||
2966 | #endif /* AUTO_INC_DEC */ | |
2967 | \f | |
2968 | /* Find the place in the rtx X where REG is used as a memory address. | |
2969 | Return the MEM rtx that so uses it. | |
2970 | If PLUSCONST is nonzero, search instead for a memory address equivalent to | |
2971 | (plus REG (const_int PLUSCONST)). | |
2972 | ||
2973 | If such an address does not appear, return 0. | |
2974 | If REG appears more than once, or is used other than in such an address, | |
2975 | return (rtx)1. */ | |
2976 | ||
8c660648 | 2977 | rtx |
d7429b6a RK |
2978 | find_use_as_address (x, reg, plusconst) |
2979 | register rtx x; | |
2980 | rtx reg; | |
e658434c | 2981 | HOST_WIDE_INT plusconst; |
d7429b6a RK |
2982 | { |
2983 | enum rtx_code code = GET_CODE (x); | |
2984 | char *fmt = GET_RTX_FORMAT (code); | |
2985 | register int i; | |
2986 | register rtx value = 0; | |
2987 | register rtx tem; | |
2988 | ||
2989 | if (code == MEM && XEXP (x, 0) == reg && plusconst == 0) | |
2990 | return x; | |
2991 | ||
2992 | if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS | |
2993 | && XEXP (XEXP (x, 0), 0) == reg | |
2994 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
2995 | && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst) | |
2996 | return x; | |
2997 | ||
2998 | if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) | |
2999 | { | |
3000 | /* If REG occurs inside a MEM used in a bit-field reference, | |
3001 | that is unacceptable. */ | |
3002 | if (find_use_as_address (XEXP (x, 0), reg, 0) != 0) | |
6fa5c106 | 3003 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
3004 | } |
3005 | ||
3006 | if (x == reg) | |
6fa5c106 | 3007 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
3008 | |
3009 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
3010 | { | |
3011 | if (fmt[i] == 'e') | |
3012 | { | |
3013 | tem = find_use_as_address (XEXP (x, i), reg, plusconst); | |
3014 | if (value == 0) | |
3015 | value = tem; | |
3016 | else if (tem != 0) | |
6fa5c106 | 3017 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
3018 | } |
3019 | if (fmt[i] == 'E') | |
3020 | { | |
3021 | register int j; | |
3022 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
3023 | { | |
3024 | tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst); | |
3025 | if (value == 0) | |
3026 | value = tem; | |
3027 | else if (tem != 0) | |
6fa5c106 | 3028 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
3029 | } |
3030 | } | |
3031 | } | |
3032 | ||
3033 | return value; | |
3034 | } | |
3035 | \f | |
3036 | /* Write information about registers and basic blocks into FILE. | |
3037 | This is part of making a debugging dump. */ | |
3038 | ||
3039 | void | |
3040 | dump_flow_info (file) | |
3041 | FILE *file; | |
3042 | { | |
3043 | register int i; | |
3044 | static char *reg_class_names[] = REG_CLASS_NAMES; | |
3045 | ||
3046 | fprintf (file, "%d registers.\n", max_regno); | |
3047 | ||
3048 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) | |
b1f21e0a | 3049 | if (REG_N_REFS (i)) |
d7429b6a | 3050 | { |
e4600702 | 3051 | enum reg_class class, altclass; |
d7429b6a | 3052 | fprintf (file, "\nRegister %d used %d times across %d insns", |
b1f21e0a MM |
3053 | i, REG_N_REFS (i), REG_LIVE_LENGTH (i)); |
3054 | if (REG_BASIC_BLOCK (i) >= 0) | |
3055 | fprintf (file, " in block %d", REG_BASIC_BLOCK (i)); | |
6fc4610b MM |
3056 | if (REG_N_SETS (i)) |
3057 | fprintf (file, "; set %d time%s", REG_N_SETS (i), | |
3058 | (REG_N_SETS (i) == 1) ? "" : "s"); | |
3059 | if (REG_USERVAR_P (regno_reg_rtx[i])) | |
3060 | fprintf (file, "; user var"); | |
b1f21e0a MM |
3061 | if (REG_N_DEATHS (i) != 1) |
3062 | fprintf (file, "; dies in %d places", REG_N_DEATHS (i)); | |
3063 | if (REG_N_CALLS_CROSSED (i) == 1) | |
d7429b6a | 3064 | fprintf (file, "; crosses 1 call"); |
b1f21e0a MM |
3065 | else if (REG_N_CALLS_CROSSED (i)) |
3066 | fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i)); | |
d7429b6a RK |
3067 | if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD) |
3068 | fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i)); | |
3069 | class = reg_preferred_class (i); | |
e4600702 RK |
3070 | altclass = reg_alternate_class (i); |
3071 | if (class != GENERAL_REGS || altclass != ALL_REGS) | |
d7429b6a | 3072 | { |
e4600702 RK |
3073 | if (altclass == ALL_REGS || class == ALL_REGS) |
3074 | fprintf (file, "; pref %s", reg_class_names[(int) class]); | |
3075 | else if (altclass == NO_REGS) | |
d7429b6a RK |
3076 | fprintf (file, "; %s or none", reg_class_names[(int) class]); |
3077 | else | |
e4600702 RK |
3078 | fprintf (file, "; pref %s, else %s", |
3079 | reg_class_names[(int) class], | |
3080 | reg_class_names[(int) altclass]); | |
d7429b6a RK |
3081 | } |
3082 | if (REGNO_POINTER_FLAG (i)) | |
3083 | fprintf (file, "; pointer"); | |
3084 | fprintf (file, ".\n"); | |
3085 | } | |
3086 | fprintf (file, "\n%d basic blocks.\n", n_basic_blocks); | |
3087 | for (i = 0; i < n_basic_blocks; i++) | |
3088 | { | |
3089 | register rtx head, jump; | |
3090 | register int regno; | |
3091 | fprintf (file, "\nBasic block %d: first insn %d, last %d.\n", | |
3092 | i, | |
3093 | INSN_UID (basic_block_head[i]), | |
3094 | INSN_UID (basic_block_end[i])); | |
3095 | /* The control flow graph's storage is freed | |
3096 | now when flow_analysis returns. | |
3097 | Don't try to print it if it is gone. */ | |
3098 | if (basic_block_drops_in) | |
3099 | { | |
3100 | fprintf (file, "Reached from blocks: "); | |
3101 | head = basic_block_head[i]; | |
3102 | if (GET_CODE (head) == CODE_LABEL) | |
3103 | for (jump = LABEL_REFS (head); | |
3104 | jump != head; | |
3105 | jump = LABEL_NEXTREF (jump)) | |
3106 | { | |
3107 | register int from_block = BLOCK_NUM (CONTAINING_INSN (jump)); | |
3108 | fprintf (file, " %d", from_block); | |
3109 | } | |
3110 | if (basic_block_drops_in[i]) | |
3111 | fprintf (file, " previous"); | |
3112 | } | |
3113 | fprintf (file, "\nRegisters live at start:"); | |
3114 | for (regno = 0; regno < max_regno; regno++) | |
916b1701 MM |
3115 | if (REGNO_REG_SET_P (basic_block_live_at_start[i], regno)) |
3116 | fprintf (file, " %d", regno); | |
d7429b6a RK |
3117 | fprintf (file, "\n"); |
3118 | } | |
3119 | fprintf (file, "\n"); | |
3120 | } | |
3e28fe44 MM |
3121 | |
3122 | \f | |
3123 | /* Like print_rtl, but also print out live information for the start of each | |
3124 | basic block. */ | |
3125 | ||
3126 | void | |
3127 | print_rtl_with_bb (outf, rtx_first) | |
3128 | FILE *outf; | |
3129 | rtx rtx_first; | |
3130 | { | |
3131 | register rtx tmp_rtx; | |
3132 | ||
3133 | if (rtx_first == 0) | |
3134 | fprintf (outf, "(nil)\n"); | |
3135 | ||
3136 | else | |
3137 | { | |
3138 | int i, bb; | |
3139 | enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; | |
3140 | int max_uid = get_max_uid (); | |
adfc539e PDM |
3141 | int *start = (int *) alloca (max_uid * sizeof (int)); |
3142 | int *end = (int *) alloca (max_uid * sizeof (int)); | |
d8d64559 | 3143 | char *in_bb_p = (char *) alloca (max_uid * sizeof (enum bb_state)); |
3e28fe44 MM |
3144 | |
3145 | for (i = 0; i < max_uid; i++) | |
3146 | { | |
3147 | start[i] = end[i] = -1; | |
3148 | in_bb_p[i] = NOT_IN_BB; | |
3149 | } | |
3150 | ||
3151 | for (i = n_basic_blocks-1; i >= 0; i--) | |
3152 | { | |
3153 | rtx x; | |
3154 | start[INSN_UID (basic_block_head[i])] = i; | |
3155 | end[INSN_UID (basic_block_end[i])] = i; | |
3156 | for (x = basic_block_head[i]; x != NULL_RTX; x = NEXT_INSN (x)) | |
3157 | { | |
1791f8e2 MM |
3158 | in_bb_p[ INSN_UID(x)] |
3159 | = (in_bb_p[ INSN_UID(x)] == NOT_IN_BB) | |
3b33f637 | 3160 | ? IN_ONE_BB : IN_MULTIPLE_BB; |
3e28fe44 MM |
3161 | if (x == basic_block_end[i]) |
3162 | break; | |
3163 | } | |
3164 | } | |
3165 | ||
3166 | for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) | |
3167 | { | |
3168 | if ((bb = start[INSN_UID (tmp_rtx)]) >= 0) | |
3169 | { | |
3170 | fprintf (outf, ";; Start of basic block %d, registers live:", | |
3171 | bb); | |
3172 | ||
3173 | EXECUTE_IF_SET_IN_REG_SET (basic_block_live_at_start[bb], 0, i, | |
3174 | { | |
3175 | fprintf (outf, " %d", i); | |
3176 | if (i < FIRST_PSEUDO_REGISTER) | |
3177 | fprintf (outf, " [%s]", | |
3178 | reg_names[i]); | |
3179 | }); | |
3180 | putc ('\n', outf); | |
3181 | } | |
3182 | ||
3183 | if (in_bb_p[ INSN_UID(tmp_rtx)] == NOT_IN_BB | |
3184 | && GET_CODE (tmp_rtx) != NOTE | |
3185 | && GET_CODE (tmp_rtx) != BARRIER) | |
3186 | fprintf (outf, ";; Insn is not within a basic block\n"); | |
3187 | else if (in_bb_p[ INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB) | |
3188 | fprintf (outf, ";; Insn is in multiple basic blocks\n"); | |
3189 | ||
3190 | print_rtl_single (outf, tmp_rtx); | |
3191 | ||
3192 | if ((bb = end[INSN_UID (tmp_rtx)]) >= 0) | |
3193 | fprintf (outf, ";; End of basic block %d\n", bb); | |
3194 | ||
3195 | putc ('\n', outf); | |
3196 | } | |
3197 | } | |
3198 | } | |
5ece9746 JL |
3199 | |
3200 | \f | |
3201 | /* Integer list support. */ | |
3202 | ||
3203 | /* Allocate a node from list *HEAD_PTR. */ | |
3204 | ||
3205 | static int_list_ptr | |
3206 | alloc_int_list_node (head_ptr) | |
3207 | int_list_block **head_ptr; | |
3208 | { | |
3209 | struct int_list_block *first_blk = *head_ptr; | |
3210 | ||
3211 | if (first_blk == NULL || first_blk->nodes_left <= 0) | |
3212 | { | |
3213 | first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block)); | |
3214 | first_blk->nodes_left = INT_LIST_NODES_IN_BLK; | |
3215 | first_blk->next = *head_ptr; | |
3216 | *head_ptr = first_blk; | |
3217 | } | |
3218 | ||
3219 | first_blk->nodes_left--; | |
3220 | return &first_blk->nodes[first_blk->nodes_left]; | |
3221 | } | |
3222 | ||
3223 | /* Pointer to head of predecessor/successor block list. */ | |
3224 | static int_list_block *pred_int_list_blocks; | |
3225 | ||
3226 | /* Add a new node to integer list LIST with value VAL. | |
3227 | LIST is a pointer to a list object to allow for different implementations. | |
3228 | If *LIST is initially NULL, the list is empty. | |
3229 | The caller must not care whether the element is added to the front or | |
3230 | to the end of the list (to allow for different implementations). */ | |
3231 | ||
3232 | static int_list_ptr | |
3233 | add_int_list_node (blk_list, list, val) | |
3234 | int_list_block **blk_list; | |
3235 | int_list **list; | |
3236 | int val; | |
3237 | { | |
3238 | int_list_ptr p = alloc_int_list_node (blk_list); | |
3239 | ||
3240 | p->val = val; | |
3241 | p->next = *list; | |
3242 | *list = p; | |
3243 | return p; | |
3244 | } | |
3245 | ||
3246 | /* Free the blocks of lists at BLK_LIST. */ | |
3247 | ||
3248 | void | |
3249 | free_int_list (blk_list) | |
3250 | int_list_block **blk_list; | |
3251 | { | |
3252 | int_list_block *p, *next; | |
3253 | ||
3254 | for (p = *blk_list; p != NULL; p = next) | |
3255 | { | |
3256 | next = p->next; | |
3257 | free (p); | |
3258 | } | |
3259 | ||
3260 | /* Mark list as empty for the next function we compile. */ | |
3261 | *blk_list = NULL; | |
3262 | } | |
3263 | \f | |
3264 | /* Predecessor/successor computation. */ | |
3265 | ||
3266 | /* Mark PRED_BB a precessor of SUCC_BB, | |
3267 | and conversely SUCC_BB a successor of PRED_BB. */ | |
3268 | ||
3269 | static void | |
3270 | add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs) | |
3271 | int pred_bb; | |
3272 | int succ_bb; | |
3273 | int_list_ptr *s_preds; | |
3274 | int_list_ptr *s_succs; | |
3275 | int *num_preds; | |
3276 | int *num_succs; | |
3277 | { | |
3278 | if (succ_bb != EXIT_BLOCK) | |
3279 | { | |
3280 | add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb); | |
3281 | num_preds[succ_bb]++; | |
3282 | } | |
3283 | if (pred_bb != ENTRY_BLOCK) | |
3284 | { | |
3285 | add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb); | |
3286 | num_succs[pred_bb]++; | |
3287 | } | |
3288 | } | |
3289 | ||
3290 | /* Compute the predecessors and successors for each block. */ | |
743bb12d | 3291 | void |
5ece9746 JL |
3292 | compute_preds_succs (s_preds, s_succs, num_preds, num_succs) |
3293 | int_list_ptr *s_preds; | |
3294 | int_list_ptr *s_succs; | |
3295 | int *num_preds; | |
3296 | int *num_succs; | |
3297 | { | |
3298 | int bb, clear_local_bb_vars = 0; | |
3299 | ||
3300 | bzero ((char *) s_preds, n_basic_blocks * sizeof (int_list_ptr)); | |
3301 | bzero ((char *) s_succs, n_basic_blocks * sizeof (int_list_ptr)); | |
3302 | bzero ((char *) num_preds, n_basic_blocks * sizeof (int)); | |
3303 | bzero ((char *) num_succs, n_basic_blocks * sizeof (int)); | |
3304 | ||
3305 | /* This routine can be called after life analysis; in that case | |
3306 | basic_block_drops_in and uid_block_number will not be available | |
3307 | and we must recompute their values. */ | |
3308 | if (basic_block_drops_in == NULL || uid_block_number == NULL) | |
3309 | { | |
3310 | clear_local_bb_vars = 1; | |
3311 | basic_block_drops_in = (char *) alloca (n_basic_blocks); | |
3312 | uid_block_number = (int *) alloca ((get_max_uid () + 1) * sizeof (int)); | |
3313 | ||
3314 | bzero ((char *) basic_block_drops_in, n_basic_blocks * sizeof (char)); | |
3315 | bzero ((char *) uid_block_number, n_basic_blocks * sizeof (int)); | |
3316 | ||
3317 | /* Scan each basic block setting basic_block_drops_in and | |
3318 | uid_block_number as needed. */ | |
3319 | for (bb = 0; bb < n_basic_blocks; bb++) | |
3320 | { | |
168cbdf9 | 3321 | rtx insn, stop_insn; |
5ece9746 | 3322 | |
168cbdf9 JL |
3323 | if (bb == 0) |
3324 | stop_insn = NULL_RTX; | |
3325 | else | |
3326 | stop_insn = basic_block_end[bb-1]; | |
3327 | ||
3328 | /* Look backwards from the start of this block. Stop if we | |
3329 | hit the start of the function or the end of a previous | |
3330 | block. Don't walk backwards through blocks that are just | |
3331 | deleted insns! */ | |
5ece9746 | 3332 | for (insn = PREV_INSN (basic_block_head[bb]); |
168cbdf9 JL |
3333 | insn && insn != stop_insn && GET_CODE (insn) == NOTE; |
3334 | insn = PREV_INSN (insn)) | |
5ece9746 JL |
3335 | ; |
3336 | ||
168cbdf9 JL |
3337 | /* Never set basic_block_drops_in for the first block. It is |
3338 | implicit. | |
3339 | ||
3340 | If we stopped on anything other than a BARRIER, then this | |
3341 | block drops in. */ | |
3342 | if (bb != 0) | |
3343 | basic_block_drops_in[bb] = (insn ? GET_CODE (insn) != BARRIER : 1); | |
5ece9746 JL |
3344 | |
3345 | insn = basic_block_head[bb]; | |
3346 | while (insn) | |
3347 | { | |
3348 | BLOCK_NUM (insn) = bb; | |
3349 | if (insn == basic_block_end[bb]) | |
3350 | break; | |
3351 | insn = NEXT_INSN (insn); | |
3352 | } | |
3353 | } | |
5ece9746 | 3354 | } |
168cbdf9 | 3355 | |
5ece9746 JL |
3356 | for (bb = 0; bb < n_basic_blocks; bb++) |
3357 | { | |
3358 | rtx head; | |
3359 | rtx jump; | |
3360 | ||
3361 | head = BLOCK_HEAD (bb); | |
3362 | ||
3363 | if (GET_CODE (head) == CODE_LABEL) | |
3364 | for (jump = LABEL_REFS (head); | |
3365 | jump != head; | |
3366 | jump = LABEL_NEXTREF (jump)) | |
168cbdf9 JL |
3367 | { |
3368 | if (! INSN_DELETED_P (CONTAINING_INSN (jump)) | |
3369 | && (GET_CODE (CONTAINING_INSN (jump)) != NOTE | |
3370 | || (NOTE_LINE_NUMBER (CONTAINING_INSN (jump)) | |
3371 | != NOTE_INSN_DELETED))) | |
3372 | add_pred_succ (BLOCK_NUM (CONTAINING_INSN (jump)), bb, | |
3373 | s_preds, s_succs, num_preds, num_succs); | |
3374 | } | |
5ece9746 JL |
3375 | |
3376 | jump = BLOCK_END (bb); | |
3377 | /* If this is a RETURN insn or a conditional jump in the last | |
3378 | basic block, or a non-jump insn in the last basic block, then | |
3379 | this block reaches the exit block. */ | |
3380 | if ((GET_CODE (jump) == JUMP_INSN && GET_CODE (PATTERN (jump)) == RETURN) | |
3381 | || (((GET_CODE (jump) == JUMP_INSN | |
3382 | && condjump_p (jump) && !simplejump_p (jump)) | |
3383 | || GET_CODE (jump) != JUMP_INSN) | |
3384 | && (bb == n_basic_blocks - 1))) | |
3385 | add_pred_succ (bb, EXIT_BLOCK, s_preds, s_succs, num_preds, num_succs); | |
3386 | ||
3387 | if (basic_block_drops_in[bb]) | |
3388 | add_pred_succ (bb - 1, bb, s_preds, s_succs, num_preds, num_succs); | |
3389 | } | |
3390 | ||
3391 | add_pred_succ (ENTRY_BLOCK, 0, s_preds, s_succs, num_preds, num_succs); | |
3392 | ||
3393 | ||
3394 | /* If we allocated any variables in temporary storage, clear out the | |
3395 | pointer to the local storage to avoid dangling pointers. */ | |
3396 | if (clear_local_bb_vars) | |
3397 | { | |
3398 | basic_block_drops_in = NULL; | |
3399 | uid_block_number = NULL; | |
3400 | ||
3401 | } | |
3402 | } | |
3403 | ||
3404 | void | |
3405 | dump_bb_data (file, preds, succs) | |
3406 | FILE *file; | |
3407 | int_list_ptr *preds; | |
3408 | int_list_ptr *succs; | |
3409 | { | |
3410 | int bb; | |
3411 | int_list_ptr p; | |
3412 | ||
3413 | fprintf (file, "BB data\n\n"); | |
3414 | for (bb = 0; bb < n_basic_blocks; bb++) | |
3415 | { | |
3416 | fprintf (file, "BB %d, start %d, end %d\n", bb, | |
3417 | INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb))); | |
3418 | fprintf (file, " preds:"); | |
3419 | for (p = preds[bb]; p != NULL; p = p->next) | |
3420 | { | |
3421 | int pred_bb = INT_LIST_VAL (p); | |
3422 | if (pred_bb == ENTRY_BLOCK) | |
3423 | fprintf (file, " entry"); | |
3424 | else | |
3425 | fprintf (file, " %d", pred_bb); | |
3426 | } | |
3427 | fprintf (file, "\n"); | |
3428 | fprintf (file, " succs:"); | |
3429 | for (p = succs[bb]; p != NULL; p = p->next) | |
3430 | { | |
3431 | int succ_bb = INT_LIST_VAL (p); | |
3432 | if (succ_bb == EXIT_BLOCK) | |
3433 | fprintf (file, " exit"); | |
3434 | else | |
3435 | fprintf (file, " %d", succ_bb); | |
3436 | } | |
3437 | fprintf (file, "\n"); | |
3438 | } | |
3439 | fprintf (file, "\n"); | |
3440 | } | |
3441 | ||
3522e0f2 JL |
3442 | void |
3443 | dump_sbitmap (file, bmap) | |
3444 | FILE *file; | |
3445 | sbitmap bmap; | |
3446 | { | |
3447 | int i,j,n; | |
3448 | int set_size = bmap->size; | |
3449 | int total_bits = bmap->n_bits; | |
3450 | ||
3451 | fprintf (file, " "); | |
3452 | for (i = n = 0; i < set_size && n < total_bits; i++) | |
3453 | { | |
3454 | for (j = 0; j < SBITMAP_ELT_BITS && n < total_bits; j++, n++) | |
3455 | { | |
3456 | if (n != 0 && n % 10 == 0) | |
3457 | fprintf (file, " "); | |
3458 | fprintf (file, "%d", (bmap->elms[i] & (1L << j)) != 0); | |
3459 | } | |
3460 | } | |
3461 | fprintf (file, "\n"); | |
3462 | } | |
3463 | ||
3464 | void | |
3465 | dump_sbitmap_vector (file, title, subtitle, bmaps, n_maps) | |
3466 | FILE *file; | |
3467 | char *title, *subtitle; | |
3468 | sbitmap *bmaps; | |
3469 | int n_maps; | |
3470 | { | |
3471 | int bb; | |
3472 | ||
3473 | fprintf (file, "%s\n", title); | |
3474 | for (bb = 0; bb < n_maps; bb++) | |
3475 | { | |
3476 | fprintf (file, "%s %d\n", subtitle, bb); | |
3477 | dump_sbitmap (file, bmaps[bb]); | |
3478 | } | |
3479 | fprintf (file, "\n"); | |
3480 | } | |
3481 | ||
5ece9746 JL |
3482 | /* Free basic block data storage. */ |
3483 | ||
3484 | void | |
3485 | free_bb_mem () | |
3486 | { | |
3487 | free_int_list (&pred_int_list_blocks); | |
3488 | } | |
3489 | \f | |
3490 | /* Bitmap manipulation routines. */ | |
3491 | ||
3492 | /* Allocate a simple bitmap of N_ELMS bits. */ | |
3493 | ||
3494 | sbitmap | |
3495 | sbitmap_alloc (n_elms) | |
3496 | int n_elms; | |
3497 | { | |
3498 | int bytes, size, amt; | |
3499 | sbitmap bmap; | |
3500 | ||
3501 | size = SBITMAP_SET_SIZE (n_elms); | |
3502 | bytes = size * sizeof (SBITMAP_ELT_TYPE); | |
3503 | amt = (sizeof (struct simple_bitmap_def) | |
3504 | + bytes - sizeof (SBITMAP_ELT_TYPE)); | |
3505 | bmap = (sbitmap) xmalloc (amt); | |
3506 | bmap->n_bits = n_elms; | |
3507 | bmap->size = size; | |
3508 | bmap->bytes = bytes; | |
3509 | return bmap; | |
3510 | } | |
3511 | ||
3512 | /* Allocate a vector of N_VECS bitmaps of N_ELMS bits. */ | |
3513 | ||
3514 | sbitmap * | |
3515 | sbitmap_vector_alloc (n_vecs, n_elms) | |
3516 | int n_vecs, n_elms; | |
3517 | { | |
a9a05945 | 3518 | int i, bytes, offset, elm_bytes, size, amt, vector_bytes; |
5ece9746 JL |
3519 | sbitmap *bitmap_vector; |
3520 | ||
3521 | size = SBITMAP_SET_SIZE (n_elms); | |
3522 | bytes = size * sizeof (SBITMAP_ELT_TYPE); | |
3523 | elm_bytes = (sizeof (struct simple_bitmap_def) | |
3524 | + bytes - sizeof (SBITMAP_ELT_TYPE)); | |
a9a05945 | 3525 | vector_bytes = n_vecs * sizeof (sbitmap *); |
5ece9746 | 3526 | |
a9a05945 DE |
3527 | /* Round up `vector_bytes' to account for the alignment requirements |
3528 | of an sbitmap. One could allocate the vector-table and set of sbitmaps | |
3529 | separately, but that requires maintaining two pointers or creating | |
3530 | a cover struct to hold both pointers (so our result is still just | |
3531 | one pointer). Neither is a bad idea, but this is simpler for now. */ | |
3532 | { | |
3533 | /* Based on DEFAULT_ALIGNMENT computation in obstack.c. */ | |
3534 | struct { char x; SBITMAP_ELT_TYPE y; } align; | |
3535 | int alignment = (char *) & align.y - & align.x; | |
3536 | vector_bytes = (vector_bytes + alignment - 1) & ~ (alignment - 1); | |
3537 | } | |
3538 | ||
3539 | amt = vector_bytes + (n_vecs * elm_bytes); | |
3540 | bitmap_vector = (sbitmap *) xmalloc (amt); | |
5ece9746 | 3541 | |
a9a05945 | 3542 | for (i = 0, offset = vector_bytes; |
5ece9746 JL |
3543 | i < n_vecs; |
3544 | i++, offset += elm_bytes) | |
3545 | { | |
3546 | sbitmap b = (sbitmap) ((char *) bitmap_vector + offset); | |
3547 | bitmap_vector[i] = b; | |
3548 | b->n_bits = n_elms; | |
3549 | b->size = size; | |
3550 | b->bytes = bytes; | |
3551 | } | |
3552 | ||
3553 | return bitmap_vector; | |
3554 | } | |
3555 | ||
3556 | /* Copy sbitmap SRC to DST. */ | |
3557 | ||
3558 | void | |
3559 | sbitmap_copy (dst, src) | |
3560 | sbitmap dst, src; | |
3561 | { | |
3562 | int i; | |
3563 | sbitmap_ptr d,s; | |
3564 | ||
3565 | s = src->elms; | |
3566 | d = dst->elms; | |
3567 | for (i = 0; i < dst->size; i++) | |
3568 | *d++ = *s++; | |
3569 | } | |
3570 | ||
3571 | /* Zero all elements in a bitmap. */ | |
3572 | ||
3573 | void | |
3574 | sbitmap_zero (bmap) | |
3575 | sbitmap bmap; | |
3576 | { | |
3577 | bzero ((char *) bmap->elms, bmap->bytes); | |
3578 | } | |
3579 | ||
3580 | /* Set to ones all elements in a bitmap. */ | |
3581 | ||
3582 | void | |
3583 | sbitmap_ones (bmap) | |
3584 | sbitmap bmap; | |
3585 | { | |
3586 | memset (bmap->elms, -1, bmap->bytes); | |
3587 | } | |
3588 | ||
3589 | /* Zero a vector of N_VECS bitmaps. */ | |
3590 | ||
3591 | void | |
3592 | sbitmap_vector_zero (bmap, n_vecs) | |
3593 | sbitmap *bmap; | |
3594 | int n_vecs; | |
3595 | { | |
3596 | int i; | |
3597 | ||
3598 | for (i = 0; i < n_vecs; i++) | |
3599 | sbitmap_zero (bmap[i]); | |
3600 | } | |
3601 | ||
3602 | /* Set to ones a vector of N_VECS bitmaps. */ | |
3603 | ||
3604 | void | |
3605 | sbitmap_vector_ones (bmap, n_vecs) | |
3606 | sbitmap *bmap; | |
3607 | int n_vecs; | |
3608 | { | |
3609 | int i; | |
3610 | ||
3611 | for (i = 0; i < n_vecs; i++) | |
3612 | sbitmap_ones (bmap[i]); | |
3613 | } | |
3614 | ||
3615 | /* Set DST to be A union (B - C). | |
3616 | DST = A | (B & ~C). | |
3617 | Return non-zero if any change is made. */ | |
3618 | ||
3619 | int | |
3620 | sbitmap_union_of_diff (dst, a, b, c) | |
3621 | sbitmap dst, a, b, c; | |
3622 | { | |
3623 | int i,changed; | |
3624 | sbitmap_ptr dstp, ap, bp, cp; | |
3625 | ||
3626 | changed = 0; | |
3627 | dstp = dst->elms; | |
3628 | ap = a->elms; | |
3629 | bp = b->elms; | |
3630 | cp = c->elms; | |
3631 | for (i = 0; i < dst->size; i++) | |
3632 | { | |
3633 | SBITMAP_ELT_TYPE tmp = *ap | (*bp & ~*cp); | |
3634 | if (*dstp != tmp) | |
3635 | changed = 1; | |
3636 | *dstp = tmp; | |
3637 | dstp++; ap++; bp++; cp++; | |
3638 | } | |
3639 | return changed; | |
3640 | } | |
3641 | ||
3642 | /* Set bitmap DST to the bitwise negation of the bitmap SRC. */ | |
3643 | ||
3644 | void | |
3645 | sbitmap_not (dst, src) | |
3646 | sbitmap dst, src; | |
3647 | { | |
3648 | int i; | |
3649 | sbitmap_ptr dstp, ap; | |
3650 | ||
3651 | dstp = dst->elms; | |
3652 | ap = src->elms; | |
3653 | for (i = 0; i < dst->size; i++) | |
3654 | { | |
3655 | SBITMAP_ELT_TYPE tmp = ~(*ap); | |
3656 | *dstp = tmp; | |
3657 | dstp++; ap++; | |
3658 | } | |
3659 | } | |
3660 | ||
3661 | /* Set the bits in DST to be the difference between the bits | |
3662 | in A and the bits in B. i.e. dst = a - b. | |
3663 | The - operator is implemented as a & (~b). */ | |
3664 | ||
3665 | void | |
3666 | sbitmap_difference (dst, a, b) | |
3667 | sbitmap dst, a, b; | |
3668 | { | |
3669 | int i; | |
3670 | sbitmap_ptr dstp, ap, bp; | |
3671 | ||
3672 | dstp = dst->elms; | |
3673 | ap = a->elms; | |
3674 | bp = b->elms; | |
3675 | for (i = 0; i < dst->size; i++) | |
3676 | *dstp++ = *ap++ & (~*bp++); | |
3677 | } | |
3678 | ||
3679 | /* Set DST to be (A and B)). | |
3680 | Return non-zero if any change is made. */ | |
3681 | ||
3682 | int | |
3683 | sbitmap_a_and_b (dst, a, b) | |
3684 | sbitmap dst, a, b; | |
3685 | { | |
3686 | int i,changed; | |
3687 | sbitmap_ptr dstp, ap, bp; | |
3688 | ||
3689 | changed = 0; | |
3690 | dstp = dst->elms; | |
3691 | ap = a->elms; | |
3692 | bp = b->elms; | |
3693 | for (i = 0; i < dst->size; i++) | |
3694 | { | |
3695 | SBITMAP_ELT_TYPE tmp = *ap & *bp; | |
3696 | if (*dstp != tmp) | |
3697 | changed = 1; | |
3698 | *dstp = tmp; | |
3699 | dstp++; ap++; bp++; | |
3700 | } | |
3701 | return changed; | |
3702 | } | |
3703 | /* Set DST to be (A or B)). | |
3704 | Return non-zero if any change is made. */ | |
3705 | ||
3706 | int | |
3707 | sbitmap_a_or_b (dst, a, b) | |
3708 | sbitmap dst, a, b; | |
3709 | { | |
3710 | int i,changed; | |
3711 | sbitmap_ptr dstp, ap, bp; | |
3712 | ||
3713 | changed = 0; | |
3714 | dstp = dst->elms; | |
3715 | ap = a->elms; | |
3716 | bp = b->elms; | |
3717 | for (i = 0; i < dst->size; i++) | |
3718 | { | |
3719 | SBITMAP_ELT_TYPE tmp = *ap | *bp; | |
3720 | if (*dstp != tmp) | |
3721 | changed = 1; | |
3722 | *dstp = tmp; | |
3723 | dstp++; ap++; bp++; | |
3724 | } | |
3725 | return changed; | |
3726 | } | |
3727 | ||
3728 | /* Set DST to be (A or (B and C)). | |
3729 | Return non-zero if any change is made. */ | |
3730 | ||
3731 | int | |
3732 | sbitmap_a_or_b_and_c (dst, a, b, c) | |
3733 | sbitmap dst, a, b, c; | |
3734 | { | |
3735 | int i,changed; | |
3736 | sbitmap_ptr dstp, ap, bp, cp; | |
3737 | ||
3738 | changed = 0; | |
3739 | dstp = dst->elms; | |
3740 | ap = a->elms; | |
3741 | bp = b->elms; | |
3742 | cp = c->elms; | |
3743 | for (i = 0; i < dst->size; i++) | |
3744 | { | |
3745 | SBITMAP_ELT_TYPE tmp = *ap | (*bp & *cp); | |
3746 | if (*dstp != tmp) | |
3747 | changed = 1; | |
3748 | *dstp = tmp; | |
3749 | dstp++; ap++; bp++; cp++; | |
3750 | } | |
3751 | return changed; | |
3752 | } | |
3753 | ||
3754 | /* Set DST to be (A ann (B or C)). | |
3755 | Return non-zero if any change is made. */ | |
3756 | ||
3757 | int | |
3758 | sbitmap_a_and_b_or_c (dst, a, b, c) | |
3759 | sbitmap dst, a, b, c; | |
3760 | { | |
3761 | int i,changed; | |
3762 | sbitmap_ptr dstp, ap, bp, cp; | |
3763 | ||
3764 | changed = 0; | |
3765 | dstp = dst->elms; | |
3766 | ap = a->elms; | |
3767 | bp = b->elms; | |
3768 | cp = c->elms; | |
3769 | for (i = 0; i < dst->size; i++) | |
3770 | { | |
3771 | SBITMAP_ELT_TYPE tmp = *ap & (*bp | *cp); | |
3772 | if (*dstp != tmp) | |
3773 | changed = 1; | |
3774 | *dstp = tmp; | |
3775 | dstp++; ap++; bp++; cp++; | |
3776 | } | |
3777 | return changed; | |
3778 | } | |
3779 | ||
3780 | /* Set the bitmap DST to the intersection of SRC of all predecessors or | |
3781 | successors of block number BB (PRED_SUCC says which). */ | |
3782 | ||
3783 | void | |
3784 | sbitmap_intersect_of_predsucc (dst, src, bb, pred_succ) | |
3785 | sbitmap dst; | |
3786 | sbitmap *src; | |
3787 | int bb; | |
3788 | int_list_ptr *pred_succ; | |
3789 | { | |
3790 | int_list_ptr ps; | |
3791 | int ps_bb; | |
3792 | int set_size = dst->size; | |
3793 | ||
3794 | ps = pred_succ[bb]; | |
3795 | ||
3796 | /* It is possible that there are no predecessors(/successors). | |
3797 | This can happen for example in unreachable code. */ | |
3798 | ||
3799 | if (ps == NULL) | |
3800 | { | |
3801 | /* In APL-speak this is the `and' reduction of the empty set and thus | |
3802 | the result is the identity for `and'. */ | |
3803 | sbitmap_ones (dst); | |
3804 | return; | |
3805 | } | |
3806 | ||
3807 | /* Set result to first predecessor/successor. */ | |
3808 | ||
3809 | for ( ; ps != NULL; ps = ps->next) | |
3810 | { | |
3811 | ps_bb = INT_LIST_VAL (ps); | |
3812 | if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK) | |
3813 | continue; | |
3814 | sbitmap_copy (dst, src[ps_bb]); | |
3815 | /* Break out since we're only doing first predecessor. */ | |
3816 | break; | |
3817 | } | |
3818 | if (ps == NULL) | |
3819 | return; | |
3820 | ||
3821 | /* Now do the remaining predecessors/successors. */ | |
3822 | ||
3823 | for (ps = ps->next; ps != NULL; ps = ps->next) | |
3824 | { | |
3825 | int i; | |
3826 | sbitmap_ptr p,r; | |
3827 | ||
3828 | ps_bb = INT_LIST_VAL (ps); | |
3829 | if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK) | |
3830 | continue; | |
3831 | ||
3832 | p = src[ps_bb]->elms; | |
3833 | r = dst->elms; | |
3834 | ||
3835 | for (i = 0; i < set_size; i++) | |
3836 | *r++ &= *p++; | |
3837 | } | |
3838 | } | |
3839 | ||
3840 | /* Set the bitmap DST to the intersection of SRC of all predecessors | |
3841 | of block number BB. */ | |
3842 | ||
3843 | void | |
3844 | sbitmap_intersect_of_predecessors (dst, src, bb, s_preds) | |
3845 | sbitmap dst; | |
3846 | sbitmap *src; | |
3847 | int bb; | |
3848 | int_list_ptr *s_preds; | |
3849 | { | |
3850 | sbitmap_intersect_of_predsucc (dst, src, bb, s_preds); | |
3851 | } | |
3852 | ||
3853 | /* Set the bitmap DST to the intersection of SRC of all successors | |
3854 | of block number BB. */ | |
3855 | ||
3856 | void | |
3857 | sbitmap_intersect_of_successors (dst, src, bb, s_succs) | |
3858 | sbitmap dst; | |
3859 | sbitmap *src; | |
3860 | int bb; | |
3861 | int_list_ptr *s_succs; | |
3862 | { | |
3863 | sbitmap_intersect_of_predsucc (dst, src, bb, s_succs); | |
3864 | } | |
3865 | ||
3866 | /* Set the bitmap DST to the union of SRC of all predecessors/successors of | |
3867 | block number BB. */ | |
3868 | ||
3869 | void | |
3870 | sbitmap_union_of_predsucc (dst, src, bb, pred_succ) | |
3871 | sbitmap dst; | |
3872 | sbitmap *src; | |
3873 | int bb; | |
3874 | int_list_ptr *pred_succ; | |
3875 | { | |
3876 | int_list_ptr ps; | |
3877 | int ps_bb; | |
3878 | int set_size = dst->size; | |
3879 | ||
3880 | ps = pred_succ[bb]; | |
3881 | ||
3882 | /* It is possible that there are no predecessors(/successors). | |
3883 | This can happen for example in unreachable code. */ | |
3884 | ||
3885 | if (ps == NULL) | |
3886 | { | |
3887 | /* In APL-speak this is the `or' reduction of the empty set and thus | |
3888 | the result is the identity for `or'. */ | |
3889 | sbitmap_zero (dst); | |
3890 | return; | |
3891 | } | |
3892 | ||
3893 | /* Set result to first predecessor/successor. */ | |
3894 | ||
3895 | for ( ; ps != NULL; ps = ps->next) | |
3896 | { | |
3897 | ps_bb = INT_LIST_VAL (ps); | |
3898 | if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK) | |
3899 | continue; | |
3900 | sbitmap_copy (dst, src[ps_bb]); | |
3901 | /* Break out since we're only doing first predecessor. */ | |
3902 | break; | |
3903 | } | |
3904 | if (ps == NULL) | |
3905 | return; | |
3906 | ||
3907 | /* Now do the remaining predecessors/successors. */ | |
3908 | ||
3909 | for (ps = ps->next; ps != NULL; ps = ps->next) | |
3910 | { | |
3911 | int i; | |
3912 | sbitmap_ptr p,r; | |
3913 | ||
3914 | ps_bb = INT_LIST_VAL (ps); | |
3915 | if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK) | |
3916 | continue; | |
3917 | ||
3918 | p = src[ps_bb]->elms; | |
3919 | r = dst->elms; | |
3920 | ||
3921 | for (i = 0; i < set_size; i++) | |
3922 | *r++ |= *p++; | |
3923 | } | |
3924 | } | |
3925 | ||
3926 | /* Set the bitmap DST to the union of SRC of all predecessors of | |
3927 | block number BB. */ | |
3928 | ||
3929 | void | |
3930 | sbitmap_union_of_predecessors (dst, src, bb, s_preds) | |
3931 | sbitmap dst; | |
3932 | sbitmap *src; | |
3933 | int bb; | |
3934 | int_list_ptr *s_preds; | |
3935 | { | |
3936 | sbitmap_union_of_predsucc (dst, src, bb, s_preds); | |
3937 | } | |
3938 | ||
5e89e58b JL |
3939 | /* Set the bitmap DST to the union of SRC of all predecessors of |
3940 | block number BB. */ | |
3941 | ||
3942 | void | |
3943 | sbitmap_union_of_successors (dst, src, bb, s_succ) | |
3944 | sbitmap dst; | |
3945 | sbitmap *src; | |
3946 | int bb; | |
3947 | int_list_ptr *s_succ; | |
3948 | { | |
3949 | sbitmap_union_of_predsucc (dst, src, bb, s_succ); | |
3950 | } | |
3951 | ||
5ece9746 JL |
3952 | /* Compute dominator relationships. */ |
3953 | void | |
3954 | compute_dominators (dominators, post_dominators, s_preds, s_succs) | |
3955 | sbitmap *dominators; | |
3956 | sbitmap *post_dominators; | |
3957 | int_list_ptr *s_preds; | |
3958 | int_list_ptr *s_succs; | |
3959 | { | |
3960 | int bb, changed, passes; | |
3961 | sbitmap *temp_bitmap; | |
3962 | ||
3963 | temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks); | |
3964 | sbitmap_vector_ones (dominators, n_basic_blocks); | |
3965 | sbitmap_vector_ones (post_dominators, n_basic_blocks); | |
3966 | sbitmap_vector_zero (temp_bitmap, n_basic_blocks); | |
3967 | ||
3968 | sbitmap_zero (dominators[0]); | |
3969 | SET_BIT (dominators[0], 0); | |
3970 | ||
3971 | sbitmap_zero (post_dominators[n_basic_blocks-1]); | |
3972 | SET_BIT (post_dominators[n_basic_blocks-1], 0); | |
3973 | ||
3974 | passes = 0; | |
3975 | changed = 1; | |
3976 | while (changed) | |
3977 | { | |
3978 | changed = 0; | |
3979 | for (bb = 1; bb < n_basic_blocks; bb++) | |
3980 | { | |
3981 | sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators, | |
3982 | bb, s_preds); | |
3983 | SET_BIT (temp_bitmap[bb], bb); | |
3984 | changed |= sbitmap_a_and_b (dominators[bb], | |
3985 | dominators[bb], | |
3986 | temp_bitmap[bb]); | |
3987 | sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators, | |
3988 | bb, s_succs); | |
3989 | SET_BIT (temp_bitmap[bb], bb); | |
3990 | changed |= sbitmap_a_and_b (post_dominators[bb], | |
3991 | post_dominators[bb], | |
3992 | temp_bitmap[bb]); | |
3993 | } | |
3994 | passes++; | |
3995 | } | |
3996 | ||
3997 | free (temp_bitmap); | |
3998 | } |