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Commit | Line | Data |
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6fb5fa3c | 1 | /* RTL dead code elimination. |
0196c95e | 2 | Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
6fb5fa3c DB |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
6fb5fa3c DB |
9 | version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
6fb5fa3c DB |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
23 | #include "hashtab.h" | |
24 | #include "tm.h" | |
25 | #include "rtl.h" | |
26 | #include "tree.h" | |
27 | #include "regs.h" | |
28 | #include "hard-reg-set.h" | |
29 | #include "flags.h" | |
35debead | 30 | #include "except.h" |
6fb5fa3c DB |
31 | #include "df.h" |
32 | #include "cselib.h" | |
33 | #include "dce.h" | |
34 | #include "timevar.h" | |
35 | #include "tree-pass.h" | |
36 | #include "dbgcnt.h" | |
0196c95e | 37 | #include "tm_p.h" |
6fb5fa3c | 38 | |
6fb5fa3c DB |
39 | |
40 | /* ------------------------------------------------------------------------- | |
41 | Core mark/delete routines | |
42 | ------------------------------------------------------------------------- */ | |
43 | ||
2e6be65e EB |
44 | /* True if we are invoked while the df engine is running; in this case, |
45 | we don't want to reenter it. */ | |
6fb5fa3c DB |
46 | static bool df_in_progress = false; |
47 | ||
6fb5fa3c DB |
48 | /* Instructions that have been marked but whose dependencies have not |
49 | yet been processed. */ | |
50 | static VEC(rtx,heap) *worklist; | |
51 | ||
2e6be65e EB |
52 | /* Bitmap of instructions marked as needed indexed by INSN_UID. */ |
53 | static sbitmap marked; | |
54 | ||
55 | /* Bitmap obstacks used for block processing by the fast algorithm. */ | |
6fb5fa3c DB |
56 | static bitmap_obstack dce_blocks_bitmap_obstack; |
57 | static bitmap_obstack dce_tmp_bitmap_obstack; | |
58 | ||
0196c95e | 59 | static bool find_call_stack_args (rtx, bool, bool, bitmap); |
6fb5fa3c | 60 | |
d4d7f1d1 RS |
61 | /* A subroutine for which BODY is part of the instruction being tested; |
62 | either the top-level pattern, or an element of a PARALLEL. The | |
63 | instruction is known not to be a bare USE or CLOBBER. */ | |
6fb5fa3c DB |
64 | |
65 | static bool | |
d4d7f1d1 | 66 | deletable_insn_p_1 (rtx body) |
6fb5fa3c | 67 | { |
6cad9859 | 68 | switch (GET_CODE (body)) |
6fb5fa3c | 69 | { |
6fb5fa3c DB |
70 | case PREFETCH: |
71 | case TRAP_IF: | |
72 | /* The UNSPEC case was added here because the ia-64 claims that | |
73 | USEs do not work after reload and generates UNSPECS rather | |
74 | than USEs. Since dce is run after reload we need to avoid | |
75 | deleting these even if they are dead. If it turns out that | |
76 | USEs really do work after reload, the ia-64 should be | |
77 | changed, and the UNSPEC case can be removed. */ | |
78 | case UNSPEC: | |
79 | return false; | |
80 | ||
d4d7f1d1 | 81 | default: |
1d65f45c | 82 | return !volatile_refs_p (body); |
d4d7f1d1 RS |
83 | } |
84 | } | |
85 | ||
2e6be65e | 86 | |
d4d7f1d1 RS |
87 | /* Return true if INSN is a normal instruction that can be deleted by |
88 | the DCE pass. */ | |
89 | ||
90 | static bool | |
0196c95e | 91 | deletable_insn_p (rtx insn, bool fast, bitmap arg_stores) |
d4d7f1d1 RS |
92 | { |
93 | rtx body, x; | |
94 | int i; | |
95 | ||
1d65f45c RH |
96 | /* Don't delete jumps, notes and the like. */ |
97 | if (!NONJUMP_INSN_P (insn)) | |
98 | return false; | |
99 | ||
100 | /* Don't delete insns that can throw. */ | |
101 | if (!insn_nothrow_p (insn)) | |
102 | return false; | |
103 | ||
5ba5ab9b KZ |
104 | if (CALL_P (insn) |
105 | /* We cannot delete calls inside of the recursive dce because | |
106 | this may cause basic blocks to be deleted and this messes up | |
107 | the rest of the stack of optimization passes. */ | |
108 | && (!df_in_progress) | |
109 | /* We cannot delete pure or const sibling calls because it is | |
110 | hard to see the result. */ | |
becfd6e5 | 111 | && (!SIBLING_CALL_P (insn)) |
5ba5ab9b KZ |
112 | /* We can delete dead const or pure calls as long as they do not |
113 | infinite loop. */ | |
becfd6e5 KZ |
114 | && (RTL_CONST_OR_PURE_CALL_P (insn) |
115 | && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn))) | |
0196c95e | 116 | return find_call_stack_args (insn, false, fast, arg_stores); |
becfd6e5 | 117 | |
d4d7f1d1 RS |
118 | body = PATTERN (insn); |
119 | switch (GET_CODE (body)) | |
120 | { | |
121 | case USE: | |
b5b8b0ac | 122 | case VAR_LOCATION: |
d4d7f1d1 RS |
123 | return false; |
124 | ||
6fb5fa3c DB |
125 | case CLOBBER: |
126 | if (fast) | |
127 | { | |
128 | /* A CLOBBER of a dead pseudo register serves no purpose. | |
129 | That is not necessarily true for hard registers until | |
130 | after reload. */ | |
6cad9859 | 131 | x = XEXP (body, 0); |
6fb5fa3c DB |
132 | return REG_P (x) && (!HARD_REGISTER_P (x) || reload_completed); |
133 | } | |
d4d7f1d1 | 134 | else |
6fb5fa3c DB |
135 | /* Because of the way that use-def chains are built, it is not |
136 | possible to tell if the clobber is dead because it can | |
137 | never be the target of a use-def chain. */ | |
138 | return false; | |
139 | ||
6cad9859 | 140 | case PARALLEL: |
d4d7f1d1 RS |
141 | for (i = XVECLEN (body, 0) - 1; i >= 0; i--) |
142 | if (!deletable_insn_p_1 (XVECEXP (body, 0, i))) | |
143 | return false; | |
144 | return true; | |
6cad9859 | 145 | |
6fb5fa3c | 146 | default: |
d4d7f1d1 | 147 | return deletable_insn_p_1 (body); |
6fb5fa3c DB |
148 | } |
149 | } | |
150 | ||
151 | ||
2e6be65e | 152 | /* Return true if INSN has been marked as needed. */ |
6fb5fa3c DB |
153 | |
154 | static inline int | |
155 | marked_insn_p (rtx insn) | |
156 | { | |
50e94c7e SB |
157 | /* Artificial defs are always needed and they do not have an insn. |
158 | We should never see them here. */ | |
159 | gcc_assert (insn); | |
160 | return TEST_BIT (marked, INSN_UID (insn)); | |
6fb5fa3c DB |
161 | } |
162 | ||
163 | ||
164 | /* If INSN has not yet been marked as needed, mark it now, and add it to | |
165 | the worklist. */ | |
166 | ||
167 | static void | |
168 | mark_insn (rtx insn, bool fast) | |
169 | { | |
170 | if (!marked_insn_p (insn)) | |
171 | { | |
172 | if (!fast) | |
173 | VEC_safe_push (rtx, heap, worklist, insn); | |
174 | SET_BIT (marked, INSN_UID (insn)); | |
175 | if (dump_file) | |
176 | fprintf (dump_file, " Adding insn %d to worklist\n", INSN_UID (insn)); | |
0196c95e JJ |
177 | if (CALL_P (insn) |
178 | && !df_in_progress | |
179 | && !SIBLING_CALL_P (insn) | |
180 | && (RTL_CONST_OR_PURE_CALL_P (insn) | |
181 | && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn))) | |
182 | find_call_stack_args (insn, true, fast, NULL); | |
6fb5fa3c DB |
183 | } |
184 | } | |
185 | ||
186 | ||
187 | /* A note_stores callback used by mark_nonreg_stores. DATA is the | |
188 | instruction containing DEST. */ | |
189 | ||
190 | static void | |
7bc980e1 | 191 | mark_nonreg_stores_1 (rtx dest, const_rtx pattern, void *data) |
6fb5fa3c DB |
192 | { |
193 | if (GET_CODE (pattern) != CLOBBER && !REG_P (dest)) | |
194 | mark_insn ((rtx) data, true); | |
195 | } | |
196 | ||
197 | ||
198 | /* A note_stores callback used by mark_nonreg_stores. DATA is the | |
199 | instruction containing DEST. */ | |
200 | ||
201 | static void | |
7bc980e1 | 202 | mark_nonreg_stores_2 (rtx dest, const_rtx pattern, void *data) |
6fb5fa3c DB |
203 | { |
204 | if (GET_CODE (pattern) != CLOBBER && !REG_P (dest)) | |
205 | mark_insn ((rtx) data, false); | |
206 | } | |
207 | ||
208 | ||
209 | /* Mark INSN if BODY stores to a non-register destination. */ | |
210 | ||
211 | static void | |
212 | mark_nonreg_stores (rtx body, rtx insn, bool fast) | |
213 | { | |
214 | if (fast) | |
215 | note_stores (body, mark_nonreg_stores_1, insn); | |
216 | else | |
217 | note_stores (body, mark_nonreg_stores_2, insn); | |
218 | } | |
219 | ||
220 | ||
0196c95e JJ |
221 | /* Try to find all stack stores of CALL_INSN arguments if |
222 | ACCUMULATE_OUTGOING_ARGS. If all stack stores have been found | |
223 | and it is therefore safe to eliminate the call, return true, | |
224 | otherwise return false. This function should be first called | |
225 | with DO_MARK false, and only when the CALL_INSN is actually | |
226 | going to be marked called again with DO_MARK true. */ | |
227 | ||
228 | static bool | |
229 | find_call_stack_args (rtx call_insn, bool do_mark, bool fast, | |
230 | bitmap arg_stores) | |
231 | { | |
232 | rtx p, insn, prev_insn; | |
233 | bool ret; | |
234 | HOST_WIDE_INT min_sp_off, max_sp_off; | |
235 | bitmap sp_bytes; | |
236 | ||
237 | gcc_assert (CALL_P (call_insn)); | |
238 | if (!ACCUMULATE_OUTGOING_ARGS) | |
239 | return true; | |
240 | ||
241 | if (!do_mark) | |
242 | { | |
243 | gcc_assert (arg_stores); | |
244 | bitmap_clear (arg_stores); | |
245 | } | |
246 | ||
247 | min_sp_off = INTTYPE_MAXIMUM (HOST_WIDE_INT); | |
248 | max_sp_off = 0; | |
249 | ||
250 | /* First determine the minimum and maximum offset from sp for | |
251 | stored arguments. */ | |
252 | for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1)) | |
253 | if (GET_CODE (XEXP (p, 0)) == USE | |
254 | && MEM_P (XEXP (XEXP (p, 0), 0))) | |
255 | { | |
256 | rtx mem = XEXP (XEXP (p, 0), 0), addr, size; | |
257 | HOST_WIDE_INT off = 0; | |
258 | size = MEM_SIZE (mem); | |
259 | if (size == NULL_RTX) | |
260 | return false; | |
261 | addr = XEXP (mem, 0); | |
262 | if (GET_CODE (addr) == PLUS | |
263 | && REG_P (XEXP (addr, 0)) | |
264 | && CONST_INT_P (XEXP (addr, 1))) | |
265 | { | |
266 | off = INTVAL (XEXP (addr, 1)); | |
267 | addr = XEXP (addr, 0); | |
268 | } | |
269 | if (addr != stack_pointer_rtx) | |
270 | { | |
271 | if (!REG_P (addr)) | |
272 | return false; | |
273 | /* If not fast, use chains to see if addr wasn't set to | |
274 | sp + offset. */ | |
275 | if (!fast) | |
276 | { | |
277 | df_ref *use_rec; | |
278 | struct df_link *defs; | |
279 | rtx set; | |
280 | ||
281 | for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++) | |
282 | if (rtx_equal_p (addr, DF_REF_REG (*use_rec))) | |
283 | break; | |
284 | ||
285 | if (*use_rec == NULL) | |
286 | return false; | |
287 | ||
288 | for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next) | |
289 | if (! DF_REF_IS_ARTIFICIAL (defs->ref)) | |
290 | break; | |
291 | ||
292 | if (defs == NULL) | |
293 | return false; | |
294 | ||
295 | set = single_set (DF_REF_INSN (defs->ref)); | |
296 | if (!set) | |
297 | return false; | |
298 | ||
299 | if (GET_CODE (SET_SRC (set)) != PLUS | |
300 | || XEXP (SET_SRC (set), 0) != stack_pointer_rtx | |
301 | || !CONST_INT_P (XEXP (SET_SRC (set), 1))) | |
302 | return false; | |
303 | ||
304 | off += INTVAL (XEXP (SET_SRC (set), 1)); | |
305 | } | |
306 | else | |
307 | return false; | |
308 | } | |
309 | min_sp_off = MIN (min_sp_off, off); | |
310 | max_sp_off = MAX (max_sp_off, off + INTVAL (size)); | |
311 | } | |
312 | ||
313 | if (min_sp_off >= max_sp_off) | |
314 | return true; | |
315 | sp_bytes = BITMAP_ALLOC (NULL); | |
316 | ||
317 | /* Set bits in SP_BYTES bitmap for bytes relative to sp + min_sp_off | |
318 | which contain arguments. Checking has been done in the previous | |
319 | loop. */ | |
320 | for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1)) | |
321 | if (GET_CODE (XEXP (p, 0)) == USE | |
322 | && MEM_P (XEXP (XEXP (p, 0), 0))) | |
323 | { | |
324 | rtx mem = XEXP (XEXP (p, 0), 0), addr; | |
325 | HOST_WIDE_INT off = 0, byte; | |
326 | addr = XEXP (mem, 0); | |
327 | if (GET_CODE (addr) == PLUS | |
328 | && REG_P (XEXP (addr, 0)) | |
329 | && CONST_INT_P (XEXP (addr, 1))) | |
330 | { | |
331 | off = INTVAL (XEXP (addr, 1)); | |
332 | addr = XEXP (addr, 0); | |
333 | } | |
334 | if (addr != stack_pointer_rtx) | |
335 | { | |
336 | df_ref *use_rec; | |
337 | struct df_link *defs; | |
338 | rtx set; | |
339 | ||
340 | for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++) | |
341 | if (rtx_equal_p (addr, DF_REF_REG (*use_rec))) | |
342 | break; | |
343 | ||
344 | for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next) | |
345 | if (! DF_REF_IS_ARTIFICIAL (defs->ref)) | |
346 | break; | |
347 | ||
348 | set = single_set (DF_REF_INSN (defs->ref)); | |
349 | off += INTVAL (XEXP (SET_SRC (set), 1)); | |
350 | } | |
351 | for (byte = off; byte < off + INTVAL (MEM_SIZE (mem)); byte++) | |
352 | { | |
821bb7f8 RG |
353 | if (!bitmap_set_bit (sp_bytes, byte - min_sp_off)) |
354 | gcc_unreachable (); | |
0196c95e JJ |
355 | } |
356 | } | |
357 | ||
358 | /* Walk backwards, looking for argument stores. The search stops | |
750900db | 359 | when seeing another call, sp adjustment or memory store other than |
0196c95e JJ |
360 | argument store. */ |
361 | ret = false; | |
362 | for (insn = PREV_INSN (call_insn); insn; insn = prev_insn) | |
363 | { | |
364 | rtx set, mem, addr; | |
365 | HOST_WIDE_INT off, byte; | |
366 | ||
367 | if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn))) | |
368 | prev_insn = NULL_RTX; | |
369 | else | |
370 | prev_insn = PREV_INSN (insn); | |
371 | ||
372 | if (CALL_P (insn)) | |
373 | break; | |
374 | ||
375 | if (!INSN_P (insn)) | |
376 | continue; | |
377 | ||
378 | set = single_set (insn); | |
379 | if (!set || SET_DEST (set) == stack_pointer_rtx) | |
380 | break; | |
381 | ||
382 | if (!MEM_P (SET_DEST (set))) | |
383 | continue; | |
384 | ||
385 | mem = SET_DEST (set); | |
386 | addr = XEXP (mem, 0); | |
387 | off = 0; | |
388 | if (GET_CODE (addr) == PLUS | |
389 | && REG_P (XEXP (addr, 0)) | |
390 | && CONST_INT_P (XEXP (addr, 1))) | |
391 | { | |
392 | off = INTVAL (XEXP (addr, 1)); | |
393 | addr = XEXP (addr, 0); | |
394 | } | |
395 | if (addr != stack_pointer_rtx) | |
396 | { | |
397 | if (!REG_P (addr)) | |
398 | break; | |
399 | if (!fast) | |
400 | { | |
401 | df_ref *use_rec; | |
402 | struct df_link *defs; | |
403 | rtx set; | |
404 | ||
405 | for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++) | |
406 | if (rtx_equal_p (addr, DF_REF_REG (*use_rec))) | |
407 | break; | |
408 | ||
409 | if (*use_rec == NULL) | |
410 | break; | |
411 | ||
412 | for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next) | |
413 | if (! DF_REF_IS_ARTIFICIAL (defs->ref)) | |
414 | break; | |
415 | ||
416 | if (defs == NULL) | |
417 | break; | |
418 | ||
419 | set = single_set (DF_REF_INSN (defs->ref)); | |
420 | if (!set) | |
421 | break; | |
422 | ||
423 | if (GET_CODE (SET_SRC (set)) != PLUS | |
424 | || XEXP (SET_SRC (set), 0) != stack_pointer_rtx | |
425 | || !CONST_INT_P (XEXP (SET_SRC (set), 1))) | |
426 | break; | |
427 | ||
428 | off += INTVAL (XEXP (SET_SRC (set), 1)); | |
429 | } | |
430 | else | |
431 | break; | |
432 | } | |
433 | ||
434 | if (GET_MODE_SIZE (GET_MODE (mem)) == 0) | |
435 | break; | |
436 | ||
437 | for (byte = off; byte < off + GET_MODE_SIZE (GET_MODE (mem)); byte++) | |
438 | { | |
439 | if (byte < min_sp_off | |
440 | || byte >= max_sp_off | |
821bb7f8 | 441 | || !bitmap_clear_bit (sp_bytes, byte - min_sp_off)) |
0196c95e | 442 | break; |
0196c95e JJ |
443 | } |
444 | ||
445 | if (!deletable_insn_p (insn, fast, NULL)) | |
446 | break; | |
447 | ||
448 | if (do_mark) | |
449 | mark_insn (insn, fast); | |
450 | else | |
451 | bitmap_set_bit (arg_stores, INSN_UID (insn)); | |
452 | ||
453 | if (bitmap_empty_p (sp_bytes)) | |
454 | { | |
455 | ret = true; | |
456 | break; | |
457 | } | |
458 | } | |
459 | ||
460 | BITMAP_FREE (sp_bytes); | |
461 | if (!ret && arg_stores) | |
462 | bitmap_clear (arg_stores); | |
463 | ||
464 | return ret; | |
465 | } | |
466 | ||
467 | ||
6fb5fa3c DB |
468 | /* Delete all REG_EQUAL notes of the registers INSN writes, to prevent |
469 | bad dangling REG_EQUAL notes. */ | |
470 | ||
471 | static void | |
472 | delete_corresponding_reg_eq_notes (rtx insn) | |
473 | { | |
57512f53 | 474 | df_ref *def_rec; |
6fb5fa3c DB |
475 | for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++) |
476 | { | |
57512f53 | 477 | df_ref def = *def_rec; |
6fb5fa3c DB |
478 | unsigned int regno = DF_REF_REGNO (def); |
479 | /* This loop is a little tricky. We cannot just go down the | |
480 | chain because it is being modified by the actions in the | |
481 | loop. So we just get the head. We plan to drain the list | |
482 | anyway. */ | |
483 | while (DF_REG_EQ_USE_CHAIN (regno)) | |
484 | { | |
57512f53 | 485 | df_ref eq_use = DF_REG_EQ_USE_CHAIN (regno); |
6fb5fa3c DB |
486 | rtx noted_insn = DF_REF_INSN (eq_use); |
487 | rtx note = find_reg_note (noted_insn, REG_EQUAL, NULL_RTX); | |
488 | if (!note) | |
489 | note = find_reg_note (noted_insn, REG_EQUIV, NULL_RTX); | |
490 | ||
491 | /* This assert is generally triggered when someone deletes a | |
492 | REG_EQUAL or REG_EQUIV note by hacking the list manually | |
493 | rather than calling remove_note. */ | |
494 | gcc_assert (note); | |
495 | remove_note (noted_insn, note); | |
496 | } | |
497 | } | |
498 | } | |
499 | ||
500 | ||
9ed7b221 | 501 | /* Delete every instruction that hasn't been marked. */ |
6fb5fa3c DB |
502 | |
503 | static void | |
504 | delete_unmarked_insns (void) | |
505 | { | |
506 | basic_block bb; | |
507 | rtx insn, next; | |
5ba5ab9b | 508 | bool must_clean = false; |
6fb5fa3c | 509 | |
cd3f1729 KZ |
510 | FOR_EACH_BB_REVERSE (bb) |
511 | FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next) | |
6fb5fa3c DB |
512 | if (INSN_P (insn)) |
513 | { | |
9ed7b221 | 514 | /* Always delete no-op moves. */ |
6fb5fa3c | 515 | if (noop_move_p (insn)) |
9ed7b221 EB |
516 | ; |
517 | ||
9ed7b221 | 518 | /* Otherwise rely only on the DCE algorithm. */ |
6fb5fa3c DB |
519 | else if (marked_insn_p (insn)) |
520 | continue; | |
521 | ||
cd3f1729 KZ |
522 | /* Beware that reaching a dbg counter limit here can result |
523 | in miscompiled file. This occurs when a group of insns | |
524 | must be deleted together, typically because the kept insn | |
525 | depends on the output from the deleted insn. Deleting | |
526 | this insns in reverse order (both at the bb level and | |
527 | when looking at the blocks) minimizes this, but does not | |
528 | eliminate it, since it is possible for the using insn to | |
529 | be top of a block and the producer to be at the bottom of | |
530 | the block. However, in most cases this will only result | |
531 | in an uninitialized use of an insn that is dead anyway. | |
532 | ||
533 | However, there is one rare case that will cause a | |
534 | miscompile: deletion of non-looping pure and constant | |
535 | calls on a machine where ACCUMULATE_OUTGOING_ARGS is true. | |
536 | In this case it is possible to remove the call, but leave | |
537 | the argument pushes to the stack. Because of the changes | |
538 | to the stack pointer, this will almost always lead to a | |
539 | miscompile. */ | |
6fb5fa3c DB |
540 | if (!dbg_cnt (dce)) |
541 | continue; | |
542 | ||
543 | if (dump_file) | |
544 | fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn)); | |
545 | ||
9ed7b221 EB |
546 | /* Before we delete the insn we have to delete REG_EQUAL notes |
547 | for the destination regs in order to avoid dangling notes. */ | |
548 | delete_corresponding_reg_eq_notes (insn); | |
6fb5fa3c | 549 | |
5ba5ab9b KZ |
550 | /* If a pure or const call is deleted, this may make the cfg |
551 | have unreachable blocks. We rememeber this and call | |
552 | delete_unreachable_blocks at the end. */ | |
553 | if (CALL_P (insn)) | |
554 | must_clean = true; | |
555 | ||
9ed7b221 | 556 | /* Now delete the insn. */ |
6fb5fa3c | 557 | delete_insn_and_edges (insn); |
6fb5fa3c | 558 | } |
5ba5ab9b KZ |
559 | |
560 | /* Deleted a pure or const call. */ | |
561 | if (must_clean) | |
562 | delete_unreachable_blocks (); | |
6fb5fa3c DB |
563 | } |
564 | ||
565 | ||
6fb5fa3c DB |
566 | /* Go through the instructions and mark those whose necessity is not |
567 | dependent on inter-instruction information. Make sure all other | |
568 | instructions are not marked. */ | |
569 | ||
570 | static void | |
571 | prescan_insns_for_dce (bool fast) | |
572 | { | |
573 | basic_block bb; | |
0196c95e JJ |
574 | rtx insn, prev; |
575 | bitmap arg_stores = NULL; | |
576 | ||
6fb5fa3c DB |
577 | if (dump_file) |
578 | fprintf (dump_file, "Finding needed instructions:\n"); | |
0196c95e JJ |
579 | |
580 | if (!df_in_progress && ACCUMULATE_OUTGOING_ARGS) | |
581 | arg_stores = BITMAP_ALLOC (NULL); | |
582 | ||
6fb5fa3c | 583 | FOR_EACH_BB (bb) |
0196c95e JJ |
584 | { |
585 | FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev) | |
586 | if (INSN_P (insn)) | |
587 | { | |
588 | /* Don't mark argument stores now. They will be marked | |
589 | if needed when the associated CALL is marked. */ | |
590 | if (arg_stores && bitmap_bit_p (arg_stores, INSN_UID (insn))) | |
591 | continue; | |
592 | if (deletable_insn_p (insn, fast, arg_stores)) | |
593 | mark_nonreg_stores (PATTERN (insn), insn, fast); | |
594 | else | |
595 | mark_insn (insn, fast); | |
596 | } | |
597 | /* find_call_stack_args only looks at argument stores in the | |
598 | same bb. */ | |
599 | if (arg_stores) | |
600 | bitmap_clear (arg_stores); | |
601 | } | |
602 | ||
603 | if (arg_stores) | |
604 | BITMAP_FREE (arg_stores); | |
6fb5fa3c DB |
605 | |
606 | if (dump_file) | |
607 | fprintf (dump_file, "Finished finding needed instructions:\n"); | |
608 | } | |
609 | ||
610 | ||
611 | /* UD-based DSE routines. */ | |
612 | ||
6ed3da00 | 613 | /* Mark instructions that define artificially-used registers, such as |
6fb5fa3c DB |
614 | the frame pointer and the stack pointer. */ |
615 | ||
616 | static void | |
617 | mark_artificial_uses (void) | |
618 | { | |
619 | basic_block bb; | |
620 | struct df_link *defs; | |
57512f53 | 621 | df_ref *use_rec; |
6fb5fa3c DB |
622 | |
623 | FOR_ALL_BB (bb) | |
624 | { | |
b8698a0f | 625 | for (use_rec = df_get_artificial_uses (bb->index); |
6fb5fa3c DB |
626 | *use_rec; use_rec++) |
627 | for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next) | |
50e94c7e SB |
628 | if (! DF_REF_IS_ARTIFICIAL (defs->ref)) |
629 | mark_insn (DF_REF_INSN (defs->ref), false); | |
6fb5fa3c DB |
630 | } |
631 | } | |
632 | ||
2e6be65e | 633 | |
6fb5fa3c DB |
634 | /* Mark every instruction that defines a register value that INSN uses. */ |
635 | ||
636 | static void | |
637 | mark_reg_dependencies (rtx insn) | |
638 | { | |
639 | struct df_link *defs; | |
57512f53 | 640 | df_ref *use_rec; |
6fb5fa3c | 641 | |
b5b8b0ac AO |
642 | if (DEBUG_INSN_P (insn)) |
643 | return; | |
644 | ||
6fb5fa3c DB |
645 | for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++) |
646 | { | |
57512f53 | 647 | df_ref use = *use_rec; |
6fb5fa3c DB |
648 | if (dump_file) |
649 | { | |
650 | fprintf (dump_file, "Processing use of "); | |
651 | print_simple_rtl (dump_file, DF_REF_REG (use)); | |
652 | fprintf (dump_file, " in insn %d:\n", INSN_UID (insn)); | |
653 | } | |
654 | for (defs = DF_REF_CHAIN (use); defs; defs = defs->next) | |
50e94c7e SB |
655 | if (! DF_REF_IS_ARTIFICIAL (defs->ref)) |
656 | mark_insn (DF_REF_INSN (defs->ref), false); | |
6fb5fa3c DB |
657 | } |
658 | } | |
659 | ||
660 | ||
2e6be65e EB |
661 | /* Initialize global variables for a new DCE pass. */ |
662 | ||
6fb5fa3c | 663 | static void |
2e6be65e EB |
664 | init_dce (bool fast) |
665 | { | |
666 | if (!df_in_progress) | |
667 | { | |
668 | if (!fast) | |
669 | df_chain_add_problem (DF_UD_CHAIN); | |
670 | df_analyze (); | |
671 | } | |
672 | ||
673 | if (dump_file) | |
674 | df_dump (dump_file); | |
675 | ||
676 | if (fast) | |
677 | { | |
678 | bitmap_obstack_initialize (&dce_blocks_bitmap_obstack); | |
679 | bitmap_obstack_initialize (&dce_tmp_bitmap_obstack); | |
680 | } | |
681 | ||
682 | marked = sbitmap_alloc (get_max_uid () + 1); | |
683 | sbitmap_zero (marked); | |
684 | } | |
685 | ||
686 | ||
687 | /* Free the data allocated by init_dce. */ | |
688 | ||
689 | static void | |
690 | fini_dce (bool fast) | |
6fb5fa3c DB |
691 | { |
692 | sbitmap_free (marked); | |
2e6be65e EB |
693 | |
694 | if (fast) | |
695 | { | |
696 | bitmap_obstack_release (&dce_blocks_bitmap_obstack); | |
697 | bitmap_obstack_release (&dce_tmp_bitmap_obstack); | |
698 | } | |
6fb5fa3c DB |
699 | } |
700 | ||
701 | ||
702 | /* UD-chain based DCE. */ | |
703 | ||
704 | static unsigned int | |
705 | rest_of_handle_ud_dce (void) | |
706 | { | |
707 | rtx insn; | |
708 | ||
6fb5fa3c DB |
709 | init_dce (false); |
710 | ||
711 | prescan_insns_for_dce (false); | |
712 | mark_artificial_uses (); | |
713 | while (VEC_length (rtx, worklist) > 0) | |
714 | { | |
715 | insn = VEC_pop (rtx, worklist); | |
716 | mark_reg_dependencies (insn); | |
717 | } | |
cf975747 | 718 | VEC_free (rtx, heap, worklist); |
2e6be65e | 719 | |
6fb5fa3c DB |
720 | /* Before any insns are deleted, we must remove the chains since |
721 | they are not bidirectional. */ | |
722 | df_remove_problem (df_chain); | |
723 | delete_unmarked_insns (); | |
724 | ||
2e6be65e | 725 | fini_dce (false); |
6fb5fa3c DB |
726 | return 0; |
727 | } | |
728 | ||
729 | ||
730 | static bool | |
731 | gate_ud_dce (void) | |
732 | { | |
7d817ebc DE |
733 | return optimize > 1 && flag_dce |
734 | && dbg_cnt (dce_ud); | |
6fb5fa3c DB |
735 | } |
736 | ||
8ddbbcae | 737 | struct rtl_opt_pass pass_ud_rtl_dce = |
6fb5fa3c | 738 | { |
8ddbbcae JH |
739 | { |
740 | RTL_PASS, | |
e0a42b0f ZC |
741 | "ud dce", /* name */ |
742 | gate_ud_dce, /* gate */ | |
743 | rest_of_handle_ud_dce, /* execute */ | |
6fb5fa3c DB |
744 | NULL, /* sub */ |
745 | NULL, /* next */ | |
746 | 0, /* static_pass_number */ | |
747 | TV_DCE, /* tv_id */ | |
748 | 0, /* properties_required */ | |
749 | 0, /* properties_provided */ | |
750 | 0, /* properties_destroyed */ | |
751 | 0, /* todo_flags_start */ | |
752 | TODO_dump_func | | |
a36b8a1e | 753 | TODO_df_finish | TODO_verify_rtl_sharing | |
8ddbbcae JH |
754 | TODO_ggc_collect /* todo_flags_finish */ |
755 | } | |
6fb5fa3c DB |
756 | }; |
757 | ||
2e6be65e | 758 | |
6fb5fa3c DB |
759 | /* ------------------------------------------------------------------------- |
760 | Fast DCE functions | |
761 | ------------------------------------------------------------------------- */ | |
762 | ||
cc806ac1 RS |
763 | /* Process basic block BB. Return true if the live_in set has |
764 | changed. REDO_OUT is true if the info at the bottom of the block | |
765 | needs to be recalculated before starting. AU is the proper set of | |
766 | artificial uses. */ | |
6fb5fa3c DB |
767 | |
768 | static bool | |
cc806ac1 | 769 | byte_dce_process_block (basic_block bb, bool redo_out, bitmap au) |
6fb5fa3c DB |
770 | { |
771 | bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack); | |
772 | rtx insn; | |
773 | bool block_changed; | |
57512f53 | 774 | df_ref *def_rec; |
6fb5fa3c DB |
775 | |
776 | if (redo_out) | |
777 | { | |
778 | /* Need to redo the live_out set of this block if when one of | |
779 | the succs of this block has had a change in it live in | |
780 | set. */ | |
781 | edge e; | |
782 | edge_iterator ei; | |
cc806ac1 RS |
783 | df_confluence_function_n con_fun_n = df_byte_lr->problem->con_fun_n; |
784 | bitmap_clear (DF_BYTE_LR_OUT (bb)); | |
6fb5fa3c DB |
785 | FOR_EACH_EDGE (e, ei, bb->succs) |
786 | (*con_fun_n) (e); | |
787 | } | |
788 | ||
789 | if (dump_file) | |
790 | { | |
791 | fprintf (dump_file, "processing block %d live out = ", bb->index); | |
cc806ac1 | 792 | df_print_byte_regset (dump_file, DF_BYTE_LR_OUT (bb)); |
6fb5fa3c DB |
793 | } |
794 | ||
cc806ac1 RS |
795 | bitmap_copy (local_live, DF_BYTE_LR_OUT (bb)); |
796 | ||
797 | df_byte_lr_simulate_artificial_refs_at_end (bb, local_live); | |
798 | ||
799 | FOR_BB_INSNS_REVERSE (bb, insn) | |
800 | if (INSN_P (insn)) | |
801 | { | |
802 | /* The insn is needed if there is someone who uses the output. */ | |
803 | for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++) | |
804 | { | |
57512f53 | 805 | df_ref def = *def_rec; |
cc806ac1 RS |
806 | unsigned int last; |
807 | unsigned int dregno = DF_REF_REGNO (def); | |
808 | unsigned int start = df_byte_lr_get_regno_start (dregno); | |
809 | unsigned int len = df_byte_lr_get_regno_len (dregno); | |
810 | ||
811 | unsigned int sb; | |
812 | unsigned int lb; | |
813 | /* This is one of the only places where DF_MM_MAY should | |
814 | be used for defs. Need to make sure that we are | |
815 | checking for all of the bits that may be used. */ | |
816 | ||
817 | if (!df_compute_accessed_bytes (def, DF_MM_MAY, &sb, &lb)) | |
818 | { | |
819 | start += sb; | |
820 | len = lb - sb; | |
821 | } | |
822 | ||
823 | if (bitmap_bit_p (au, dregno)) | |
824 | { | |
825 | mark_insn (insn, true); | |
826 | goto quickexit; | |
827 | } | |
b8698a0f | 828 | |
cc806ac1 RS |
829 | last = start + len; |
830 | while (start < last) | |
831 | if (bitmap_bit_p (local_live, start++)) | |
832 | { | |
833 | mark_insn (insn, true); | |
834 | goto quickexit; | |
835 | } | |
836 | } | |
b8698a0f L |
837 | |
838 | quickexit: | |
839 | ||
cc806ac1 RS |
840 | /* No matter if the instruction is needed or not, we remove |
841 | any regno in the defs from the live set. */ | |
842 | df_byte_lr_simulate_defs (insn, local_live); | |
843 | ||
844 | /* On the other hand, we do not allow the dead uses to set | |
845 | anything in local_live. */ | |
846 | if (marked_insn_p (insn)) | |
847 | df_byte_lr_simulate_uses (insn, local_live); | |
848 | ||
849 | if (dump_file) | |
850 | { | |
b8698a0f | 851 | fprintf (dump_file, "finished processing insn %d live out = ", |
cc806ac1 RS |
852 | INSN_UID (insn)); |
853 | df_print_byte_regset (dump_file, local_live); | |
854 | } | |
855 | } | |
b8698a0f | 856 | |
cc806ac1 RS |
857 | df_byte_lr_simulate_artificial_refs_at_top (bb, local_live); |
858 | ||
859 | block_changed = !bitmap_equal_p (local_live, DF_BYTE_LR_IN (bb)); | |
860 | if (block_changed) | |
861 | bitmap_copy (DF_BYTE_LR_IN (bb), local_live); | |
862 | BITMAP_FREE (local_live); | |
863 | return block_changed; | |
864 | } | |
865 | ||
866 | ||
867 | /* Process basic block BB. Return true if the live_in set has | |
868 | changed. REDO_OUT is true if the info at the bottom of the block | |
869 | needs to be recalculated before starting. AU is the proper set of | |
870 | artificial uses. */ | |
871 | ||
872 | static bool | |
873 | dce_process_block (basic_block bb, bool redo_out, bitmap au) | |
874 | { | |
875 | bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack); | |
876 | rtx insn; | |
877 | bool block_changed; | |
57512f53 | 878 | df_ref *def_rec; |
6fb5fa3c | 879 | |
cc806ac1 | 880 | if (redo_out) |
6fb5fa3c | 881 | { |
cc806ac1 RS |
882 | /* Need to redo the live_out set of this block if when one of |
883 | the succs of this block has had a change in it live in | |
884 | set. */ | |
885 | edge e; | |
886 | edge_iterator ei; | |
887 | df_confluence_function_n con_fun_n = df_lr->problem->con_fun_n; | |
888 | bitmap_clear (DF_LR_OUT (bb)); | |
889 | FOR_EACH_EDGE (e, ei, bb->succs) | |
890 | (*con_fun_n) (e); | |
6fb5fa3c DB |
891 | } |
892 | ||
cc806ac1 | 893 | if (dump_file) |
6fb5fa3c | 894 | { |
fafe34f9 | 895 | fprintf (dump_file, "processing block %d lr out = ", bb->index); |
cc806ac1 | 896 | df_print_regset (dump_file, DF_LR_OUT (bb)); |
6fb5fa3c DB |
897 | } |
898 | ||
cc806ac1 RS |
899 | bitmap_copy (local_live, DF_LR_OUT (bb)); |
900 | ||
02b47899 | 901 | df_simulate_initialize_backwards (bb, local_live); |
541d3103 | 902 | |
6fb5fa3c DB |
903 | FOR_BB_INSNS_REVERSE (bb, insn) |
904 | if (INSN_P (insn)) | |
905 | { | |
9ed7b221 EB |
906 | bool needed = false; |
907 | ||
908 | /* The insn is needed if there is someone who uses the output. */ | |
909 | for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++) | |
910 | if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec)) | |
911 | || bitmap_bit_p (au, DF_REF_REGNO (*def_rec))) | |
912 | { | |
913 | needed = true; | |
914 | break; | |
915 | } | |
b8698a0f | 916 | |
9ed7b221 EB |
917 | if (needed) |
918 | mark_insn (insn, true); | |
b8698a0f | 919 | |
6fb5fa3c DB |
920 | /* No matter if the instruction is needed or not, we remove |
921 | any regno in the defs from the live set. */ | |
922 | df_simulate_defs (insn, local_live); | |
923 | ||
924 | /* On the other hand, we do not allow the dead uses to set | |
925 | anything in local_live. */ | |
926 | if (marked_insn_p (insn)) | |
927 | df_simulate_uses (insn, local_live); | |
928 | } | |
b8698a0f | 929 | |
02b47899 | 930 | df_simulate_finalize_backwards (bb, local_live); |
6fb5fa3c DB |
931 | |
932 | block_changed = !bitmap_equal_p (local_live, DF_LR_IN (bb)); | |
933 | if (block_changed) | |
934 | bitmap_copy (DF_LR_IN (bb), local_live); | |
935 | ||
936 | BITMAP_FREE (local_live); | |
937 | return block_changed; | |
938 | } | |
939 | ||
2e6be65e | 940 | |
cc806ac1 RS |
941 | /* Perform fast DCE once initialization is done. If BYTE_LEVEL is |
942 | true, use the byte level dce, otherwise do it at the pseudo | |
943 | level. */ | |
2e6be65e | 944 | |
6fb5fa3c | 945 | static void |
cc806ac1 | 946 | fast_dce (bool byte_level) |
6fb5fa3c DB |
947 | { |
948 | int *postorder = df_get_postorder (DF_BACKWARD); | |
949 | int n_blocks = df_get_n_blocks (DF_BACKWARD); | |
6fb5fa3c DB |
950 | /* The set of blocks that have been seen on this iteration. */ |
951 | bitmap processed = BITMAP_ALLOC (&dce_blocks_bitmap_obstack); | |
952 | /* The set of blocks that need to have the out vectors reset because | |
953 | the in of one of their successors has changed. */ | |
954 | bitmap redo_out = BITMAP_ALLOC (&dce_blocks_bitmap_obstack); | |
955 | bitmap all_blocks = BITMAP_ALLOC (&dce_blocks_bitmap_obstack); | |
956 | bool global_changed = true; | |
cc806ac1 RS |
957 | |
958 | /* These regs are considered always live so if they end up dying | |
959 | because of some def, we need to bring the back again. Calling | |
960 | df_simulate_fixup_sets has the disadvantage of calling | |
961 | bb_has_eh_pred once per insn, so we cache the information | |
962 | here. */ | |
963 | bitmap au = df->regular_block_artificial_uses; | |
964 | bitmap au_eh = df->eh_block_artificial_uses; | |
9ed7b221 | 965 | int i; |
6fb5fa3c DB |
966 | |
967 | prescan_insns_for_dce (true); | |
968 | ||
969 | for (i = 0; i < n_blocks; i++) | |
970 | bitmap_set_bit (all_blocks, postorder[i]); | |
971 | ||
972 | while (global_changed) | |
973 | { | |
974 | global_changed = false; | |
9ed7b221 | 975 | |
6fb5fa3c DB |
976 | for (i = 0; i < n_blocks; i++) |
977 | { | |
978 | int index = postorder[i]; | |
979 | basic_block bb = BASIC_BLOCK (index); | |
980 | bool local_changed; | |
981 | ||
982 | if (index < NUM_FIXED_BLOCKS) | |
983 | { | |
984 | bitmap_set_bit (processed, index); | |
985 | continue; | |
986 | } | |
987 | ||
cc806ac1 | 988 | if (byte_level) |
b8698a0f | 989 | local_changed |
cc806ac1 RS |
990 | = byte_dce_process_block (bb, bitmap_bit_p (redo_out, index), |
991 | bb_has_eh_pred (bb) ? au_eh : au); | |
992 | else | |
b8698a0f | 993 | local_changed |
cc806ac1 RS |
994 | = dce_process_block (bb, bitmap_bit_p (redo_out, index), |
995 | bb_has_eh_pred (bb) ? au_eh : au); | |
6fb5fa3c | 996 | bitmap_set_bit (processed, index); |
b8698a0f | 997 | |
6fb5fa3c DB |
998 | if (local_changed) |
999 | { | |
1000 | edge e; | |
1001 | edge_iterator ei; | |
1002 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1003 | if (bitmap_bit_p (processed, e->src->index)) | |
1004 | /* Be tricky about when we need to iterate the | |
1005 | analysis. We only have redo the analysis if the | |
1006 | bitmaps change at the top of a block that is the | |
1007 | entry to a loop. */ | |
1008 | global_changed = true; | |
1009 | else | |
1010 | bitmap_set_bit (redo_out, e->src->index); | |
1011 | } | |
1012 | } | |
b8698a0f | 1013 | |
6fb5fa3c DB |
1014 | if (global_changed) |
1015 | { | |
1016 | /* Turn off the RUN_DCE flag to prevent recursive calls to | |
1017 | dce. */ | |
1018 | int old_flag = df_clear_flags (DF_LR_RUN_DCE); | |
1019 | ||
1020 | /* So something was deleted that requires a redo. Do it on | |
1021 | the cheap. */ | |
1022 | delete_unmarked_insns (); | |
1023 | sbitmap_zero (marked); | |
1024 | bitmap_clear (processed); | |
1025 | bitmap_clear (redo_out); | |
b8698a0f | 1026 | |
6fb5fa3c DB |
1027 | /* We do not need to rescan any instructions. We only need |
1028 | to redo the dataflow equations for the blocks that had a | |
1029 | change at the top of the block. Then we need to redo the | |
b8698a0f | 1030 | iteration. */ |
cc806ac1 RS |
1031 | if (byte_level) |
1032 | df_analyze_problem (df_byte_lr, all_blocks, postorder, n_blocks); | |
1033 | else | |
1034 | df_analyze_problem (df_lr, all_blocks, postorder, n_blocks); | |
6fb5fa3c DB |
1035 | |
1036 | if (old_flag & DF_LR_RUN_DCE) | |
1037 | df_set_flags (DF_LR_RUN_DCE); | |
9ed7b221 | 1038 | |
6fb5fa3c DB |
1039 | prescan_insns_for_dce (true); |
1040 | } | |
6fb5fa3c DB |
1041 | } |
1042 | ||
1043 | delete_unmarked_insns (); | |
1044 | ||
1045 | BITMAP_FREE (processed); | |
1046 | BITMAP_FREE (redo_out); | |
1047 | BITMAP_FREE (all_blocks); | |
1048 | } | |
1049 | ||
1050 | ||
cc806ac1 | 1051 | /* Fast register level DCE. */ |
6fb5fa3c DB |
1052 | |
1053 | static unsigned int | |
1054 | rest_of_handle_fast_dce (void) | |
1055 | { | |
1056 | init_dce (true); | |
cc806ac1 RS |
1057 | fast_dce (false); |
1058 | fini_dce (true); | |
1059 | return 0; | |
1060 | } | |
1061 | ||
1062 | ||
1063 | /* Fast byte level DCE. */ | |
1064 | ||
1065 | static unsigned int | |
1066 | rest_of_handle_fast_byte_dce (void) | |
1067 | { | |
1068 | df_byte_lr_add_problem (); | |
1069 | init_dce (true); | |
1070 | fast_dce (true); | |
2e6be65e | 1071 | fini_dce (true); |
6fb5fa3c DB |
1072 | return 0; |
1073 | } | |
1074 | ||
1075 | ||
1076 | /* This is an internal call that is used by the df live register | |
1077 | problem to run fast dce as a side effect of creating the live | |
1078 | information. The stack is organized so that the lr problem is run, | |
1079 | this pass is run, which updates the live info and the df scanning | |
1080 | info, and then returns to allow the rest of the problems to be run. | |
1081 | ||
1082 | This can be called by elsewhere but it will not update the bit | |
2e6be65e | 1083 | vectors for any other problems than LR. */ |
6fb5fa3c DB |
1084 | |
1085 | void | |
1086 | run_fast_df_dce (void) | |
1087 | { | |
1088 | if (flag_dce) | |
1089 | { | |
1090 | /* If dce is able to delete something, it has to happen | |
1091 | immediately. Otherwise there will be problems handling the | |
1092 | eq_notes. */ | |
81f40b79 ILT |
1093 | int old_flags = |
1094 | df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN); | |
1095 | ||
6fb5fa3c DB |
1096 | df_in_progress = true; |
1097 | rest_of_handle_fast_dce (); | |
2e6be65e EB |
1098 | df_in_progress = false; |
1099 | ||
6fb5fa3c DB |
1100 | df_set_flags (old_flags); |
1101 | } | |
1102 | } | |
1103 | ||
2e6be65e | 1104 | |
9ed7b221 EB |
1105 | /* Run a fast DCE pass. */ |
1106 | ||
1107 | void | |
1108 | run_fast_dce (void) | |
6fb5fa3c | 1109 | { |
9ed7b221 EB |
1110 | if (flag_dce) |
1111 | rest_of_handle_fast_dce (); | |
6fb5fa3c DB |
1112 | } |
1113 | ||
1114 | ||
9ed7b221 EB |
1115 | static bool |
1116 | gate_fast_dce (void) | |
6fb5fa3c | 1117 | { |
7d817ebc DE |
1118 | return optimize > 0 && flag_dce |
1119 | && dbg_cnt (dce_fast); | |
6fb5fa3c DB |
1120 | } |
1121 | ||
8ddbbcae | 1122 | struct rtl_opt_pass pass_fast_rtl_dce = |
6fb5fa3c | 1123 | { |
8ddbbcae JH |
1124 | { |
1125 | RTL_PASS, | |
e0a42b0f | 1126 | "rtl dce", /* name */ |
6fb5fa3c DB |
1127 | gate_fast_dce, /* gate */ |
1128 | rest_of_handle_fast_dce, /* execute */ | |
1129 | NULL, /* sub */ | |
1130 | NULL, /* next */ | |
1131 | 0, /* static_pass_number */ | |
1132 | TV_DCE, /* tv_id */ | |
1133 | 0, /* properties_required */ | |
1134 | 0, /* properties_provided */ | |
1135 | 0, /* properties_destroyed */ | |
1136 | 0, /* todo_flags_start */ | |
1137 | TODO_dump_func | | |
a36b8a1e | 1138 | TODO_df_finish | TODO_verify_rtl_sharing | |
8ddbbcae JH |
1139 | TODO_ggc_collect /* todo_flags_finish */ |
1140 | } | |
6fb5fa3c | 1141 | }; |
cc806ac1 RS |
1142 | |
1143 | struct rtl_opt_pass pass_fast_rtl_byte_dce = | |
1144 | { | |
1145 | { | |
1146 | RTL_PASS, | |
1147 | "byte-dce", /* name */ | |
1148 | gate_fast_dce, /* gate */ | |
1149 | rest_of_handle_fast_byte_dce, /* execute */ | |
1150 | NULL, /* sub */ | |
1151 | NULL, /* next */ | |
1152 | 0, /* static_pass_number */ | |
1153 | TV_DCE, /* tv_id */ | |
1154 | 0, /* properties_required */ | |
1155 | 0, /* properties_provided */ | |
1156 | 0, /* properties_destroyed */ | |
1157 | 0, /* todo_flags_start */ | |
1158 | TODO_dump_func | | |
1159 | TODO_df_finish | TODO_verify_rtl_sharing | | |
1160 | TODO_ggc_collect /* todo_flags_finish */ | |
1161 | } | |
1162 | }; |