]>
Commit | Line | Data |
---|---|---|
402209ff JH |
1 | /* Control flow optimization code for GNU compiler. |
2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, | |
d9221e01 | 3 | 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. |
402209ff JH |
4 | |
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
21 | ||
22 | /* This file contains optimizer of the control flow. The main entrypoint is | |
23 | cleanup_cfg. Following optimizations are performed: | |
24 | ||
25 | - Unreachable blocks removal | |
d1a6adeb | 26 | - Edge forwarding (edge to the forwarder block is forwarded to its |
eaec9b3d | 27 | successor. Simplification of the branch instruction is performed by |
402209ff | 28 | underlying infrastructure so branch can be converted to simplejump or |
f5143c46 | 29 | eliminated). |
402209ff JH |
30 | - Cross jumping (tail merging) |
31 | - Conditional jump-around-simplejump simplification | |
32 | - Basic block merging. */ | |
33 | ||
34 | #include "config.h" | |
35 | #include "system.h" | |
4977bab6 ZW |
36 | #include "coretypes.h" |
37 | #include "tm.h" | |
402209ff JH |
38 | #include "rtl.h" |
39 | #include "hard-reg-set.h" | |
40 | #include "basic-block.h" | |
41 | #include "timevar.h" | |
42 | #include "output.h" | |
43 | #include "insn-config.h" | |
44 | #include "flags.h" | |
45 | #include "recog.h" | |
46 | #include "toplev.h" | |
8ecba28a | 47 | #include "cselib.h" |
5f24e0dc | 48 | #include "params.h" |
9f16e871 | 49 | #include "tm_p.h" |
e4ec2cac | 50 | #include "target.h" |
66fd46b6 | 51 | #include "regs.h" |
750054a2 | 52 | #include "cfglayout.h" |
2b3493c8 | 53 | #include "expr.h" |
402209ff | 54 | |
79f5e6be | 55 | /* cleanup_cfg maintains following flags for each basic block. */ |
5f0d2358 RK |
56 | |
57 | enum bb_flags | |
58 | { | |
635559ab JH |
59 | /* Set if BB is the forwarder block to avoid too many |
60 | forwarder_block_p calls. */ | |
1540f9eb JH |
61 | BB_FORWARDER_BLOCK = 1, |
62 | BB_NONTHREADABLE_BLOCK = 2 | |
5f0d2358 | 63 | }; |
635559ab | 64 | |
5f0d2358 RK |
65 | #define BB_FLAGS(BB) (enum bb_flags) (BB)->aux |
66 | #define BB_SET_FLAG(BB, FLAG) \ | |
67 | (BB)->aux = (void *) (long) ((enum bb_flags) (BB)->aux | (FLAG)) | |
68 | #define BB_CLEAR_FLAG(BB, FLAG) \ | |
69 | (BB)->aux = (void *) (long) ((enum bb_flags) (BB)->aux & ~(FLAG)) | |
635559ab | 70 | |
5f0d2358 | 71 | #define FORWARDER_BLOCK_P(BB) (BB_FLAGS (BB) & BB_FORWARDER_BLOCK) |
635559ab | 72 | |
7cf240d5 JH |
73 | /* Set to true when we are running first pass of try_optimize_cfg loop. */ |
74 | static bool first_pass; | |
d329e058 AJ |
75 | static bool try_crossjump_to_edge (int, edge, edge); |
76 | static bool try_crossjump_bb (int, basic_block); | |
77 | static bool outgoing_edges_match (int, basic_block, basic_block); | |
78 | static int flow_find_cross_jump (int, basic_block, basic_block, rtx *, rtx *); | |
79 | static bool insns_match_p (int, rtx, rtx); | |
80 | ||
d329e058 AJ |
81 | static bool tail_recursion_label_p (rtx); |
82 | static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block); | |
83 | static void merge_blocks_move_successor_nojumps (basic_block, basic_block); | |
d329e058 AJ |
84 | static bool try_optimize_cfg (int); |
85 | static bool try_simplify_condjump (basic_block); | |
86 | static bool try_forward_edges (int, basic_block); | |
87 | static edge thread_jump (int, edge, basic_block); | |
88 | static bool mark_effect (rtx, bitmap); | |
89 | static void notice_new_block (basic_block); | |
90 | static void update_forwarder_flag (basic_block); | |
91 | static int mentions_nonequal_regs (rtx *, void *); | |
2b3493c8 | 92 | static void merge_memattrs (rtx, rtx); |
635559ab JH |
93 | \f |
94 | /* Set flags for newly created block. */ | |
95 | ||
96 | static void | |
d329e058 | 97 | notice_new_block (basic_block bb) |
635559ab JH |
98 | { |
99 | if (!bb) | |
100 | return; | |
5f0d2358 | 101 | |
635559ab JH |
102 | if (forwarder_block_p (bb)) |
103 | BB_SET_FLAG (bb, BB_FORWARDER_BLOCK); | |
104 | } | |
105 | ||
106 | /* Recompute forwarder flag after block has been modified. */ | |
107 | ||
108 | static void | |
d329e058 | 109 | update_forwarder_flag (basic_block bb) |
635559ab JH |
110 | { |
111 | if (forwarder_block_p (bb)) | |
112 | BB_SET_FLAG (bb, BB_FORWARDER_BLOCK); | |
113 | else | |
114 | BB_CLEAR_FLAG (bb, BB_FORWARDER_BLOCK); | |
115 | } | |
402209ff JH |
116 | \f |
117 | /* Simplify a conditional jump around an unconditional jump. | |
118 | Return true if something changed. */ | |
119 | ||
120 | static bool | |
d329e058 | 121 | try_simplify_condjump (basic_block cbranch_block) |
402209ff JH |
122 | { |
123 | basic_block jump_block, jump_dest_block, cbranch_dest_block; | |
124 | edge cbranch_jump_edge, cbranch_fallthru_edge; | |
125 | rtx cbranch_insn; | |
9778f2f8 JH |
126 | rtx insn, next; |
127 | rtx end; | |
402209ff JH |
128 | |
129 | /* Verify that there are exactly two successors. */ | |
130 | if (!cbranch_block->succ | |
131 | || !cbranch_block->succ->succ_next | |
132 | || cbranch_block->succ->succ_next->succ_next) | |
133 | return false; | |
134 | ||
135 | /* Verify that we've got a normal conditional branch at the end | |
136 | of the block. */ | |
a813c111 | 137 | cbranch_insn = BB_END (cbranch_block); |
402209ff JH |
138 | if (!any_condjump_p (cbranch_insn)) |
139 | return false; | |
140 | ||
141 | cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block); | |
142 | cbranch_jump_edge = BRANCH_EDGE (cbranch_block); | |
143 | ||
144 | /* The next block must not have multiple predecessors, must not | |
145 | be the last block in the function, and must contain just the | |
146 | unconditional jump. */ | |
147 | jump_block = cbranch_fallthru_edge->dest; | |
148 | if (jump_block->pred->pred_next | |
f6366fc7 | 149 | || jump_block->next_bb == EXIT_BLOCK_PTR |
635559ab | 150 | || !FORWARDER_BLOCK_P (jump_block)) |
402209ff JH |
151 | return false; |
152 | jump_dest_block = jump_block->succ->dest; | |
153 | ||
750054a2 CT |
154 | /* If we are partitioning hot/cold basic blocks, we don't want to |
155 | mess up unconditional or indirect jumps that cross between hot | |
156 | and cold sections. */ | |
157 | ||
158 | if (flag_reorder_blocks_and_partition | |
159 | && (jump_block->partition != jump_dest_block->partition | |
160 | || cbranch_jump_edge->crossing_edge)) | |
161 | return false; | |
162 | ||
402209ff JH |
163 | /* The conditional branch must target the block after the |
164 | unconditional branch. */ | |
165 | cbranch_dest_block = cbranch_jump_edge->dest; | |
166 | ||
167 | if (!can_fallthru (jump_block, cbranch_dest_block)) | |
168 | return false; | |
169 | ||
ca6c03ca JH |
170 | /* Invert the conditional branch. */ |
171 | if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 0)) | |
172 | return false; | |
402209ff | 173 | |
c263766c RH |
174 | if (dump_file) |
175 | fprintf (dump_file, "Simplifying condjump %i around jump %i\n", | |
a813c111 | 176 | INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block))); |
402209ff JH |
177 | |
178 | /* Success. Update the CFG to match. Note that after this point | |
179 | the edge variable names appear backwards; the redirection is done | |
180 | this way to preserve edge profile data. */ | |
181 | cbranch_jump_edge = redirect_edge_succ_nodup (cbranch_jump_edge, | |
182 | cbranch_dest_block); | |
183 | cbranch_fallthru_edge = redirect_edge_succ_nodup (cbranch_fallthru_edge, | |
184 | jump_dest_block); | |
185 | cbranch_jump_edge->flags |= EDGE_FALLTHRU; | |
186 | cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU; | |
b446e5a2 | 187 | update_br_prob_note (cbranch_block); |
402209ff | 188 | |
a813c111 | 189 | end = BB_END (jump_block); |
9778f2f8 | 190 | /* Deleting a block may produce unreachable code warning even when we are |
ba228239 | 191 | not deleting anything live. Suppress it by moving all the line number |
9778f2f8 | 192 | notes out of the block. */ |
a813c111 | 193 | for (insn = BB_HEAD (jump_block); insn != NEXT_INSN (BB_END (jump_block)); |
9778f2f8 JH |
194 | insn = next) |
195 | { | |
196 | next = NEXT_INSN (insn); | |
197 | if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0) | |
198 | { | |
a813c111 | 199 | if (insn == BB_END (jump_block)) |
470d9044 | 200 | { |
a813c111 | 201 | BB_END (jump_block) = PREV_INSN (insn); |
1ab237df | 202 | if (insn == end) |
470d9044 JH |
203 | break; |
204 | } | |
205 | reorder_insns_nobb (insn, insn, end); | |
9778f2f8 JH |
206 | end = insn; |
207 | } | |
208 | } | |
402209ff | 209 | /* Delete the block with the unconditional jump, and clean up the mess. */ |
f470c378 ZD |
210 | delete_basic_block (jump_block); |
211 | tidy_fallthru_edge (cbranch_jump_edge); | |
402209ff JH |
212 | |
213 | return true; | |
214 | } | |
215 | \f | |
8ecba28a JH |
216 | /* Attempt to prove that operation is NOOP using CSElib or mark the effect |
217 | on register. Used by jump threading. */ | |
5f0d2358 | 218 | |
8ecba28a | 219 | static bool |
d329e058 | 220 | mark_effect (rtx exp, regset nonequal) |
8ecba28a | 221 | { |
9f16e871 JH |
222 | int regno; |
223 | rtx dest; | |
8ecba28a JH |
224 | switch (GET_CODE (exp)) |
225 | { | |
226 | /* In case we do clobber the register, mark it as equal, as we know the | |
227 | value is dead so it don't have to match. */ | |
f87c27b4 KH |
228 | case CLOBBER: |
229 | if (REG_P (XEXP (exp, 0))) | |
230 | { | |
231 | dest = XEXP (exp, 0); | |
232 | regno = REGNO (dest); | |
233 | CLEAR_REGNO_REG_SET (nonequal, regno); | |
234 | if (regno < FIRST_PSEUDO_REGISTER) | |
235 | { | |
66fd46b6 | 236 | int n = hard_regno_nregs[regno][GET_MODE (dest)]; |
f87c27b4 KH |
237 | while (--n > 0) |
238 | CLEAR_REGNO_REG_SET (nonequal, regno + n); | |
239 | } | |
240 | } | |
241 | return false; | |
5f0d2358 | 242 | |
f87c27b4 KH |
243 | case SET: |
244 | if (rtx_equal_for_cselib_p (SET_DEST (exp), SET_SRC (exp))) | |
8ecba28a | 245 | return false; |
f87c27b4 KH |
246 | dest = SET_DEST (exp); |
247 | if (dest == pc_rtx) | |
8ecba28a | 248 | return false; |
f87c27b4 KH |
249 | if (!REG_P (dest)) |
250 | return true; | |
251 | regno = REGNO (dest); | |
252 | SET_REGNO_REG_SET (nonequal, regno); | |
253 | if (regno < FIRST_PSEUDO_REGISTER) | |
254 | { | |
66fd46b6 | 255 | int n = hard_regno_nregs[regno][GET_MODE (dest)]; |
f87c27b4 KH |
256 | while (--n > 0) |
257 | SET_REGNO_REG_SET (nonequal, regno + n); | |
258 | } | |
259 | return false; | |
260 | ||
261 | default: | |
262 | return false; | |
8ecba28a JH |
263 | } |
264 | } | |
fe477d8b | 265 | |
dcc24678 | 266 | /* Return nonzero if X is a register set in regset DATA. |
fe477d8b JH |
267 | Called via for_each_rtx. */ |
268 | static int | |
d329e058 | 269 | mentions_nonequal_regs (rtx *x, void *data) |
fe477d8b JH |
270 | { |
271 | regset nonequal = (regset) data; | |
272 | if (REG_P (*x)) | |
273 | { | |
274 | int regno; | |
275 | ||
276 | regno = REGNO (*x); | |
277 | if (REGNO_REG_SET_P (nonequal, regno)) | |
278 | return 1; | |
279 | if (regno < FIRST_PSEUDO_REGISTER) | |
280 | { | |
66fd46b6 | 281 | int n = hard_regno_nregs[regno][GET_MODE (*x)]; |
fe477d8b JH |
282 | while (--n > 0) |
283 | if (REGNO_REG_SET_P (nonequal, regno + n)) | |
284 | return 1; | |
285 | } | |
286 | } | |
287 | return 0; | |
288 | } | |
8ecba28a | 289 | /* Attempt to prove that the basic block B will have no side effects and |
95bd1dd7 | 290 | always continues in the same edge if reached via E. Return the edge |
8ecba28a JH |
291 | if exist, NULL otherwise. */ |
292 | ||
293 | static edge | |
d329e058 | 294 | thread_jump (int mode, edge e, basic_block b) |
8ecba28a JH |
295 | { |
296 | rtx set1, set2, cond1, cond2, insn; | |
297 | enum rtx_code code1, code2, reversed_code2; | |
298 | bool reverse1 = false; | |
299 | int i; | |
300 | regset nonequal; | |
301 | bool failed = false; | |
302 | ||
1540f9eb JH |
303 | if (BB_FLAGS (b) & BB_NONTHREADABLE_BLOCK) |
304 | return NULL; | |
305 | ||
8ecba28a JH |
306 | /* At the moment, we do handle only conditional jumps, but later we may |
307 | want to extend this code to tablejumps and others. */ | |
308 | if (!e->src->succ->succ_next || e->src->succ->succ_next->succ_next) | |
309 | return NULL; | |
310 | if (!b->succ || !b->succ->succ_next || b->succ->succ_next->succ_next) | |
1540f9eb JH |
311 | { |
312 | BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK); | |
313 | return NULL; | |
314 | } | |
8ecba28a JH |
315 | |
316 | /* Second branch must end with onlyjump, as we will eliminate the jump. */ | |
a813c111 | 317 | if (!any_condjump_p (BB_END (e->src))) |
8ecba28a | 318 | return NULL; |
f87c27b4 | 319 | |
a813c111 | 320 | if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b))) |
1540f9eb JH |
321 | { |
322 | BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK); | |
323 | return NULL; | |
324 | } | |
8ecba28a | 325 | |
a813c111 SB |
326 | set1 = pc_set (BB_END (e->src)); |
327 | set2 = pc_set (BB_END (b)); | |
8ecba28a | 328 | if (((e->flags & EDGE_FALLTHRU) != 0) |
68f3f6f1 | 329 | != (XEXP (SET_SRC (set1), 1) == pc_rtx)) |
8ecba28a JH |
330 | reverse1 = true; |
331 | ||
332 | cond1 = XEXP (SET_SRC (set1), 0); | |
333 | cond2 = XEXP (SET_SRC (set2), 0); | |
334 | if (reverse1) | |
a813c111 | 335 | code1 = reversed_comparison_code (cond1, BB_END (e->src)); |
8ecba28a JH |
336 | else |
337 | code1 = GET_CODE (cond1); | |
338 | ||
339 | code2 = GET_CODE (cond2); | |
a813c111 | 340 | reversed_code2 = reversed_comparison_code (cond2, BB_END (b)); |
8ecba28a JH |
341 | |
342 | if (!comparison_dominates_p (code1, code2) | |
343 | && !comparison_dominates_p (code1, reversed_code2)) | |
344 | return NULL; | |
345 | ||
346 | /* Ensure that the comparison operators are equivalent. | |
95bd1dd7 | 347 | ??? This is far too pessimistic. We should allow swapped operands, |
8ecba28a JH |
348 | different CCmodes, or for example comparisons for interval, that |
349 | dominate even when operands are not equivalent. */ | |
350 | if (!rtx_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
351 | || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
352 | return NULL; | |
353 | ||
354 | /* Short circuit cases where block B contains some side effects, as we can't | |
355 | safely bypass it. */ | |
a813c111 | 356 | for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)); |
8ecba28a JH |
357 | insn = NEXT_INSN (insn)) |
358 | if (INSN_P (insn) && side_effects_p (PATTERN (insn))) | |
1540f9eb JH |
359 | { |
360 | BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK); | |
361 | return NULL; | |
362 | } | |
8ecba28a | 363 | |
463301c3 | 364 | cselib_init (false); |
8ecba28a JH |
365 | |
366 | /* First process all values computed in the source basic block. */ | |
a813c111 | 367 | for (insn = NEXT_INSN (BB_HEAD (e->src)); insn != NEXT_INSN (BB_END (e->src)); |
8ecba28a JH |
368 | insn = NEXT_INSN (insn)) |
369 | if (INSN_P (insn)) | |
370 | cselib_process_insn (insn); | |
371 | ||
372 | nonequal = BITMAP_XMALLOC(); | |
373 | CLEAR_REG_SET (nonequal); | |
5f0d2358 | 374 | |
8ecba28a JH |
375 | /* Now assume that we've continued by the edge E to B and continue |
376 | processing as if it were same basic block. | |
8ecba28a | 377 | Our goal is to prove that whole block is an NOOP. */ |
5f0d2358 | 378 | |
a813c111 | 379 | for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)) && !failed; |
8ecba28a | 380 | insn = NEXT_INSN (insn)) |
f87c27b4 KH |
381 | { |
382 | if (INSN_P (insn)) | |
383 | { | |
384 | rtx pat = PATTERN (insn); | |
385 | ||
386 | if (GET_CODE (pat) == PARALLEL) | |
387 | { | |
388 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
389 | failed |= mark_effect (XVECEXP (pat, 0, i), nonequal); | |
390 | } | |
391 | else | |
392 | failed |= mark_effect (pat, nonequal); | |
393 | } | |
5f0d2358 | 394 | |
f87c27b4 KH |
395 | cselib_process_insn (insn); |
396 | } | |
8ecba28a JH |
397 | |
398 | /* Later we should clear nonequal of dead registers. So far we don't | |
399 | have life information in cfg_cleanup. */ | |
400 | if (failed) | |
1540f9eb JH |
401 | { |
402 | BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK); | |
403 | goto failed_exit; | |
404 | } | |
8ecba28a | 405 | |
fe477d8b JH |
406 | /* cond2 must not mention any register that is not equal to the |
407 | former block. */ | |
408 | if (for_each_rtx (&cond2, mentions_nonequal_regs, nonequal)) | |
409 | goto failed_exit; | |
410 | ||
8ecba28a JH |
411 | /* In case liveness information is available, we need to prove equivalence |
412 | only of the live values. */ | |
413 | if (mode & CLEANUP_UPDATE_LIFE) | |
414 | AND_REG_SET (nonequal, b->global_live_at_end); | |
415 | ||
416 | EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, goto failed_exit;); | |
417 | ||
418 | BITMAP_XFREE (nonequal); | |
419 | cselib_finish (); | |
420 | if ((comparison_dominates_p (code1, code2) != 0) | |
4deaa2f8 | 421 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) |
8ecba28a JH |
422 | return BRANCH_EDGE (b); |
423 | else | |
424 | return FALLTHRU_EDGE (b); | |
425 | ||
426 | failed_exit: | |
427 | BITMAP_XFREE (nonequal); | |
428 | cselib_finish (); | |
429 | return NULL; | |
430 | } | |
431 | \f | |
402209ff | 432 | /* Attempt to forward edges leaving basic block B. |
eaec9b3d | 433 | Return true if successful. */ |
402209ff JH |
434 | |
435 | static bool | |
d329e058 | 436 | try_forward_edges (int mode, basic_block b) |
402209ff JH |
437 | { |
438 | bool changed = false; | |
1c570418 | 439 | edge e, next, *threaded_edges = NULL; |
402209ff | 440 | |
750054a2 CT |
441 | /* If we are partitioning hot/cold basic blocks, we don't want to |
442 | mess up unconditional or indirect jumps that cross between hot | |
443 | and cold sections. */ | |
444 | ||
445 | if (flag_reorder_blocks_and_partition | |
446 | && find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)) | |
447 | return false; | |
448 | ||
5f0d2358 | 449 | for (e = b->succ; e; e = next) |
402209ff JH |
450 | { |
451 | basic_block target, first; | |
452 | int counter; | |
8ecba28a | 453 | bool threaded = false; |
bcb3bc6d | 454 | int nthreaded_edges = 0; |
7cf240d5 | 455 | bool may_thread = first_pass | (b->flags & BB_DIRTY); |
402209ff JH |
456 | |
457 | next = e->succ_next; | |
458 | ||
459 | /* Skip complex edges because we don't know how to update them. | |
460 | ||
eaec9b3d | 461 | Still handle fallthru edges, as we can succeed to forward fallthru |
402209ff | 462 | edge to the same place as the branch edge of conditional branch |
eaec9b3d | 463 | and turn conditional branch to an unconditional branch. */ |
402209ff JH |
464 | if (e->flags & EDGE_COMPLEX) |
465 | continue; | |
466 | ||
467 | target = first = e->dest; | |
468 | counter = 0; | |
469 | ||
0b17ab2f | 470 | while (counter < n_basic_blocks) |
402209ff | 471 | { |
8ecba28a JH |
472 | basic_block new_target = NULL; |
473 | bool new_target_threaded = false; | |
7cf240d5 | 474 | may_thread |= target->flags & BB_DIRTY; |
8ecba28a JH |
475 | |
476 | if (FORWARDER_BLOCK_P (target) | |
477 | && target->succ->dest != EXIT_BLOCK_PTR) | |
478 | { | |
479 | /* Bypass trivial infinite loops. */ | |
480 | if (target == target->succ->dest) | |
0b17ab2f | 481 | counter = n_basic_blocks; |
8ecba28a JH |
482 | new_target = target->succ->dest; |
483 | } | |
5f0d2358 | 484 | |
8ecba28a JH |
485 | /* Allow to thread only over one edge at time to simplify updating |
486 | of probabilities. */ | |
7cf240d5 | 487 | else if ((mode & CLEANUP_THREADING) && may_thread) |
8ecba28a | 488 | { |
1c570418 JH |
489 | edge t = thread_jump (mode, e, target); |
490 | if (t) | |
8ecba28a | 491 | { |
bcb3bc6d | 492 | if (!threaded_edges) |
1c570418 | 493 | threaded_edges = xmalloc (sizeof (*threaded_edges) |
0b17ab2f | 494 | * n_basic_blocks); |
3b3b1e32 RH |
495 | else |
496 | { | |
497 | int i; | |
498 | ||
499 | /* Detect an infinite loop across blocks not | |
500 | including the start block. */ | |
501 | for (i = 0; i < nthreaded_edges; ++i) | |
502 | if (threaded_edges[i] == t) | |
503 | break; | |
504 | if (i < nthreaded_edges) | |
b90e45ae | 505 | { |
0b17ab2f | 506 | counter = n_basic_blocks; |
b90e45ae JH |
507 | break; |
508 | } | |
3b3b1e32 RH |
509 | } |
510 | ||
511 | /* Detect an infinite loop across the start block. */ | |
512 | if (t->dest == b) | |
513 | break; | |
514 | ||
0b17ab2f | 515 | if (nthreaded_edges >= n_basic_blocks) |
3b3b1e32 | 516 | abort (); |
1c570418 | 517 | threaded_edges[nthreaded_edges++] = t; |
3b3b1e32 RH |
518 | |
519 | new_target = t->dest; | |
520 | new_target_threaded = true; | |
8ecba28a JH |
521 | } |
522 | } | |
5f0d2358 | 523 | |
8ecba28a JH |
524 | if (!new_target) |
525 | break; | |
402209ff JH |
526 | |
527 | /* Avoid killing of loop pre-headers, as it is the place loop | |
528 | optimizer wants to hoist code to. | |
529 | ||
530 | For fallthru forwarders, the LOOP_BEG note must appear between | |
531 | the header of block and CODE_LABEL of the loop, for non forwarders | |
532 | it must appear before the JUMP_INSN. */ | |
1c4a429a | 533 | if ((mode & CLEANUP_PRE_LOOP) && optimize) |
402209ff JH |
534 | { |
535 | rtx insn = (target->succ->flags & EDGE_FALLTHRU | |
a813c111 | 536 | ? BB_HEAD (target) : prev_nonnote_insn (BB_END (target))); |
402209ff JH |
537 | |
538 | if (GET_CODE (insn) != NOTE) | |
539 | insn = NEXT_INSN (insn); | |
540 | ||
5f0d2358 | 541 | for (; insn && GET_CODE (insn) != CODE_LABEL && !INSN_P (insn); |
402209ff JH |
542 | insn = NEXT_INSN (insn)) |
543 | if (GET_CODE (insn) == NOTE | |
544 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
545 | break; | |
546 | ||
547 | if (GET_CODE (insn) == NOTE) | |
548 | break; | |
ac19be7e DJ |
549 | |
550 | /* Do not clean up branches to just past the end of a loop | |
551 | at this time; it can mess up the loop optimizer's | |
991b6592 | 552 | recognition of some patterns. */ |
ac19be7e | 553 | |
a813c111 | 554 | insn = PREV_INSN (BB_HEAD (target)); |
ac19be7e DJ |
555 | if (insn && GET_CODE (insn) == NOTE |
556 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
557 | break; | |
402209ff | 558 | } |
5f0d2358 | 559 | |
8ecba28a JH |
560 | counter++; |
561 | target = new_target; | |
562 | threaded |= new_target_threaded; | |
f87c27b4 | 563 | } |
402209ff | 564 | |
0b17ab2f | 565 | if (counter >= n_basic_blocks) |
402209ff | 566 | { |
c263766c RH |
567 | if (dump_file) |
568 | fprintf (dump_file, "Infinite loop in BB %i.\n", | |
0b17ab2f | 569 | target->index); |
402209ff JH |
570 | } |
571 | else if (target == first) | |
572 | ; /* We didn't do anything. */ | |
573 | else | |
574 | { | |
575 | /* Save the values now, as the edge may get removed. */ | |
576 | gcov_type edge_count = e->count; | |
577 | int edge_probability = e->probability; | |
8ecba28a | 578 | int edge_frequency; |
1c570418 | 579 | int n = 0; |
402209ff | 580 | |
6ee3c8e4 JJ |
581 | /* Don't force if target is exit block. */ |
582 | if (threaded && target != EXIT_BLOCK_PTR) | |
402209ff | 583 | { |
8ecba28a | 584 | notice_new_block (redirect_edge_and_branch_force (e, target)); |
c263766c RH |
585 | if (dump_file) |
586 | fprintf (dump_file, "Conditionals threaded.\n"); | |
402209ff | 587 | } |
8ecba28a | 588 | else if (!redirect_edge_and_branch (e, target)) |
402209ff | 589 | { |
c263766c RH |
590 | if (dump_file) |
591 | fprintf (dump_file, | |
5f0d2358 | 592 | "Forwarding edge %i->%i to %i failed.\n", |
0b17ab2f | 593 | b->index, e->dest->index, target->index); |
8ecba28a | 594 | continue; |
402209ff | 595 | } |
5f0d2358 | 596 | |
8ecba28a JH |
597 | /* We successfully forwarded the edge. Now update profile |
598 | data: for each edge we traversed in the chain, remove | |
599 | the original edge's execution count. */ | |
600 | edge_frequency = ((edge_probability * b->frequency | |
601 | + REG_BR_PROB_BASE / 2) | |
602 | / REG_BR_PROB_BASE); | |
603 | ||
604 | if (!FORWARDER_BLOCK_P (b) && forwarder_block_p (b)) | |
605 | BB_SET_FLAG (b, BB_FORWARDER_BLOCK); | |
8ecba28a JH |
606 | |
607 | do | |
608 | { | |
609 | edge t; | |
5f0d2358 | 610 | |
8ecba28a | 611 | first->count -= edge_count; |
b446e5a2 JH |
612 | if (first->count < 0) |
613 | first->count = 0; | |
8ecba28a | 614 | first->frequency -= edge_frequency; |
b446e5a2 JH |
615 | if (first->frequency < 0) |
616 | first->frequency = 0; | |
8ecba28a | 617 | if (first->succ->succ_next) |
3b3b1e32 | 618 | { |
bcb3bc6d JH |
619 | edge e; |
620 | int prob; | |
3b3b1e32 RH |
621 | if (n >= nthreaded_edges) |
622 | abort (); | |
623 | t = threaded_edges [n++]; | |
bcb3bc6d JH |
624 | if (t->src != first) |
625 | abort (); | |
626 | if (first->frequency) | |
627 | prob = edge_frequency * REG_BR_PROB_BASE / first->frequency; | |
628 | else | |
629 | prob = 0; | |
b446e5a2 JH |
630 | if (prob > t->probability) |
631 | prob = t->probability; | |
bcb3bc6d JH |
632 | t->probability -= prob; |
633 | prob = REG_BR_PROB_BASE - prob; | |
b446e5a2 | 634 | if (prob <= 0) |
bcb3bc6d JH |
635 | { |
636 | first->succ->probability = REG_BR_PROB_BASE; | |
637 | first->succ->succ_next->probability = 0; | |
638 | } | |
639 | else | |
640 | for (e = first->succ; e; e = e->succ_next) | |
641 | e->probability = ((e->probability * REG_BR_PROB_BASE) | |
642 | / (double) prob); | |
b446e5a2 | 643 | update_br_prob_note (first); |
3b3b1e32 | 644 | } |
8ecba28a | 645 | else |
bcb3bc6d JH |
646 | { |
647 | /* It is possible that as the result of | |
648 | threading we've removed edge as it is | |
649 | threaded to the fallthru edge. Avoid | |
650 | getting out of sync. */ | |
651 | if (n < nthreaded_edges | |
652 | && first == threaded_edges [n]->src) | |
653 | n++; | |
654 | t = first->succ; | |
f87c27b4 | 655 | } |
5f0d2358 | 656 | |
b446e5a2 JH |
657 | t->count -= edge_count; |
658 | if (t->count < 0) | |
659 | t->count = 0; | |
8ecba28a JH |
660 | first = t->dest; |
661 | } | |
662 | while (first != target); | |
663 | ||
664 | changed = true; | |
402209ff JH |
665 | } |
666 | } | |
667 | ||
1c570418 JH |
668 | if (threaded_edges) |
669 | free (threaded_edges); | |
402209ff JH |
670 | return changed; |
671 | } | |
672 | \f | |
4262e623 JH |
673 | /* Return true if LABEL is used for tail recursion. */ |
674 | ||
675 | static bool | |
d329e058 | 676 | tail_recursion_label_p (rtx label) |
402209ff JH |
677 | { |
678 | rtx x; | |
679 | ||
680 | for (x = tail_recursion_label_list; x; x = XEXP (x, 1)) | |
681 | if (label == XEXP (x, 0)) | |
4262e623 | 682 | return true; |
402209ff | 683 | |
4262e623 | 684 | return false; |
402209ff JH |
685 | } |
686 | ||
687 | /* Blocks A and B are to be merged into a single block. A has no incoming | |
688 | fallthru edge, so it can be moved before B without adding or modifying | |
689 | any jumps (aside from the jump from A to B). */ | |
690 | ||
4262e623 | 691 | static void |
d329e058 | 692 | merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b) |
402209ff JH |
693 | { |
694 | rtx barrier; | |
402209ff | 695 | |
750054a2 CT |
696 | /* If we are partitioning hot/cold basic blocks, we don't want to |
697 | mess up unconditional or indirect jumps that cross between hot | |
698 | and cold sections. */ | |
699 | ||
700 | if (flag_reorder_blocks_and_partition | |
701 | && (a->partition != b->partition | |
702 | || find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX))) | |
703 | return; | |
704 | ||
a813c111 | 705 | barrier = next_nonnote_insn (BB_END (a)); |
402209ff JH |
706 | if (GET_CODE (barrier) != BARRIER) |
707 | abort (); | |
53c17031 | 708 | delete_insn (barrier); |
402209ff JH |
709 | |
710 | /* Move block and loop notes out of the chain so that we do not | |
711 | disturb their order. | |
712 | ||
713 | ??? A better solution would be to squeeze out all the non-nested notes | |
714 | and adjust the block trees appropriately. Even better would be to have | |
715 | a tighter connection between block trees and rtl so that this is not | |
716 | necessary. */ | |
a813c111 | 717 | if (squeeze_notes (&BB_HEAD (a), &BB_END (a))) |
2b7d71b2 | 718 | abort (); |
402209ff JH |
719 | |
720 | /* Scramble the insn chain. */ | |
a813c111 SB |
721 | if (BB_END (a) != PREV_INSN (BB_HEAD (b))) |
722 | reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b))); | |
38c1593d | 723 | a->flags |= BB_DIRTY; |
402209ff | 724 | |
c263766c RH |
725 | if (dump_file) |
726 | fprintf (dump_file, "Moved block %d before %d and merged.\n", | |
0b17ab2f | 727 | a->index, b->index); |
402209ff | 728 | |
bf77398c | 729 | /* Swap the records for the two blocks around. */ |
402209ff | 730 | |
918ed612 ZD |
731 | unlink_block (a); |
732 | link_block (a, b->prev_bb); | |
733 | ||
402209ff | 734 | /* Now blocks A and B are contiguous. Merge them. */ |
bc35512f | 735 | merge_blocks (a, b); |
402209ff JH |
736 | } |
737 | ||
738 | /* Blocks A and B are to be merged into a single block. B has no outgoing | |
739 | fallthru edge, so it can be moved after A without adding or modifying | |
740 | any jumps (aside from the jump from A to B). */ | |
741 | ||
4262e623 | 742 | static void |
d329e058 | 743 | merge_blocks_move_successor_nojumps (basic_block a, basic_block b) |
402209ff | 744 | { |
f62ce55b | 745 | rtx barrier, real_b_end; |
ee735eef | 746 | rtx label, table; |
402209ff | 747 | |
750054a2 CT |
748 | /* If we are partitioning hot/cold basic blocks, we don't want to |
749 | mess up unconditional or indirect jumps that cross between hot | |
750 | and cold sections. */ | |
751 | ||
752 | if (flag_reorder_blocks_and_partition | |
753 | && (find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX) | |
754 | || a->partition != b->partition)) | |
755 | return; | |
756 | ||
a813c111 | 757 | real_b_end = BB_END (b); |
402209ff | 758 | |
ee735eef JZ |
759 | /* If there is a jump table following block B temporarily add the jump table |
760 | to block B so that it will also be moved to the correct location. */ | |
a813c111 SB |
761 | if (tablejump_p (BB_END (b), &label, &table) |
762 | && prev_active_insn (label) == BB_END (b)) | |
402209ff | 763 | { |
a813c111 | 764 | BB_END (b) = table; |
402209ff JH |
765 | } |
766 | ||
767 | /* There had better have been a barrier there. Delete it. */ | |
a813c111 | 768 | barrier = NEXT_INSN (BB_END (b)); |
402209ff | 769 | if (barrier && GET_CODE (barrier) == BARRIER) |
53c17031 | 770 | delete_insn (barrier); |
402209ff JH |
771 | |
772 | /* Move block and loop notes out of the chain so that we do not | |
773 | disturb their order. | |
774 | ||
775 | ??? A better solution would be to squeeze out all the non-nested notes | |
776 | and adjust the block trees appropriately. Even better would be to have | |
777 | a tighter connection between block trees and rtl so that this is not | |
778 | necessary. */ | |
a813c111 | 779 | if (squeeze_notes (&BB_HEAD (b), &BB_END (b))) |
2b7d71b2 | 780 | abort (); |
402209ff JH |
781 | |
782 | /* Scramble the insn chain. */ | |
a813c111 | 783 | reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a)); |
402209ff | 784 | |
f62ce55b | 785 | /* Restore the real end of b. */ |
a813c111 | 786 | BB_END (b) = real_b_end; |
f62ce55b | 787 | |
c263766c RH |
788 | if (dump_file) |
789 | fprintf (dump_file, "Moved block %d after %d and merged.\n", | |
0b17ab2f | 790 | b->index, a->index); |
2150ad33 RH |
791 | |
792 | /* Now blocks A and B are contiguous. Merge them. */ | |
bc35512f | 793 | merge_blocks (a, b); |
402209ff JH |
794 | } |
795 | ||
796 | /* Attempt to merge basic blocks that are potentially non-adjacent. | |
ec3ae3da JH |
797 | Return NULL iff the attempt failed, otherwise return basic block |
798 | where cleanup_cfg should continue. Because the merging commonly | |
799 | moves basic block away or introduces another optimization | |
e0bb17a8 | 800 | possibility, return basic block just before B so cleanup_cfg don't |
ec3ae3da JH |
801 | need to iterate. |
802 | ||
803 | It may be good idea to return basic block before C in the case | |
804 | C has been moved after B and originally appeared earlier in the | |
4d6922ee | 805 | insn sequence, but we have no information available about the |
ec3ae3da JH |
806 | relative ordering of these two. Hopefully it is not too common. */ |
807 | ||
808 | static basic_block | |
bc35512f | 809 | merge_blocks_move (edge e, basic_block b, basic_block c, int mode) |
402209ff | 810 | { |
ec3ae3da | 811 | basic_block next; |
402209ff JH |
812 | /* If C has a tail recursion label, do not merge. There is no |
813 | edge recorded from the call_placeholder back to this label, as | |
814 | that would make optimize_sibling_and_tail_recursive_calls more | |
815 | complex for no gain. */ | |
4262e623 | 816 | if ((mode & CLEANUP_PRE_SIBCALL) |
a813c111 SB |
817 | && GET_CODE (BB_HEAD (c)) == CODE_LABEL |
818 | && tail_recursion_label_p (BB_HEAD (c))) | |
ec3ae3da | 819 | return NULL; |
402209ff | 820 | |
750054a2 CT |
821 | /* If we are partitioning hot/cold basic blocks, we don't want to |
822 | mess up unconditional or indirect jumps that cross between hot | |
823 | and cold sections. */ | |
824 | ||
825 | if (flag_reorder_blocks_and_partition | |
826 | && (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX) | |
827 | || find_reg_note (BB_END (c), REG_CROSSING_JUMP, NULL_RTX) | |
828 | || b->partition != c->partition)) | |
829 | return NULL; | |
830 | ||
831 | ||
832 | ||
402209ff JH |
833 | /* If B has a fallthru edge to C, no need to move anything. */ |
834 | if (e->flags & EDGE_FALLTHRU) | |
835 | { | |
0b17ab2f | 836 | int b_index = b->index, c_index = c->index; |
bc35512f | 837 | merge_blocks (b, c); |
635559ab | 838 | update_forwarder_flag (b); |
402209ff | 839 | |
c263766c RH |
840 | if (dump_file) |
841 | fprintf (dump_file, "Merged %d and %d without moving.\n", | |
f87c27b4 | 842 | b_index, c_index); |
402209ff | 843 | |
ec3ae3da | 844 | return b->prev_bb == ENTRY_BLOCK_PTR ? b : b->prev_bb; |
402209ff | 845 | } |
5f0d2358 | 846 | |
402209ff JH |
847 | /* Otherwise we will need to move code around. Do that only if expensive |
848 | transformations are allowed. */ | |
849 | else if (mode & CLEANUP_EXPENSIVE) | |
850 | { | |
4262e623 JH |
851 | edge tmp_edge, b_fallthru_edge; |
852 | bool c_has_outgoing_fallthru; | |
853 | bool b_has_incoming_fallthru; | |
402209ff JH |
854 | |
855 | /* Avoid overactive code motion, as the forwarder blocks should be | |
856 | eliminated by edge redirection instead. One exception might have | |
857 | been if B is a forwarder block and C has no fallthru edge, but | |
858 | that should be cleaned up by bb-reorder instead. */ | |
635559ab | 859 | if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c)) |
ec3ae3da | 860 | return NULL; |
402209ff JH |
861 | |
862 | /* We must make sure to not munge nesting of lexical blocks, | |
863 | and loop notes. This is done by squeezing out all the notes | |
864 | and leaving them there to lie. Not ideal, but functional. */ | |
865 | ||
866 | for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next) | |
867 | if (tmp_edge->flags & EDGE_FALLTHRU) | |
868 | break; | |
5f0d2358 | 869 | |
402209ff | 870 | c_has_outgoing_fallthru = (tmp_edge != NULL); |
402209ff JH |
871 | |
872 | for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next) | |
873 | if (tmp_edge->flags & EDGE_FALLTHRU) | |
874 | break; | |
5f0d2358 | 875 | |
402209ff | 876 | b_has_incoming_fallthru = (tmp_edge != NULL); |
4262e623 | 877 | b_fallthru_edge = tmp_edge; |
ec3ae3da | 878 | next = b->prev_bb; |
912b79e7 JH |
879 | if (next == c) |
880 | next = next->prev_bb; | |
4262e623 JH |
881 | |
882 | /* Otherwise, we're going to try to move C after B. If C does | |
883 | not have an outgoing fallthru, then it can be moved | |
884 | immediately after B without introducing or modifying jumps. */ | |
885 | if (! c_has_outgoing_fallthru) | |
886 | { | |
887 | merge_blocks_move_successor_nojumps (b, c); | |
ec3ae3da | 888 | return next == ENTRY_BLOCK_PTR ? next->next_bb : next; |
4262e623 | 889 | } |
402209ff JH |
890 | |
891 | /* If B does not have an incoming fallthru, then it can be moved | |
892 | immediately before C without introducing or modifying jumps. | |
893 | C cannot be the first block, so we do not have to worry about | |
894 | accessing a non-existent block. */ | |
402209ff | 895 | |
4262e623 JH |
896 | if (b_has_incoming_fallthru) |
897 | { | |
473fb060 | 898 | basic_block bb; |
5f0d2358 | 899 | |
4262e623 | 900 | if (b_fallthru_edge->src == ENTRY_BLOCK_PTR) |
ec3ae3da | 901 | return NULL; |
7dddfb65 JH |
902 | bb = force_nonfallthru (b_fallthru_edge); |
903 | if (bb) | |
904 | notice_new_block (bb); | |
4262e623 | 905 | } |
5f0d2358 | 906 | |
4262e623 | 907 | merge_blocks_move_predecessor_nojumps (b, c); |
ec3ae3da | 908 | return next == ENTRY_BLOCK_PTR ? next->next_bb : next; |
402209ff | 909 | } |
5f0d2358 | 910 | |
10d6c0d0 | 911 | return NULL; |
402209ff JH |
912 | } |
913 | \f | |
0dd0e980 | 914 | |
2b3493c8 AK |
915 | /* Removes the memory attributes of MEM expression |
916 | if they are not equal. */ | |
917 | ||
918 | void | |
919 | merge_memattrs (rtx x, rtx y) | |
920 | { | |
921 | int i; | |
922 | int j; | |
923 | enum rtx_code code; | |
924 | const char *fmt; | |
925 | ||
926 | if (x == y) | |
927 | return; | |
928 | if (x == 0 || y == 0) | |
929 | return; | |
930 | ||
931 | code = GET_CODE (x); | |
932 | ||
933 | if (code != GET_CODE (y)) | |
934 | return; | |
935 | ||
936 | if (GET_MODE (x) != GET_MODE (y)) | |
937 | return; | |
938 | ||
939 | if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y)) | |
940 | { | |
941 | if (! MEM_ATTRS (x)) | |
942 | MEM_ATTRS (y) = 0; | |
943 | else if (! MEM_ATTRS (y)) | |
944 | MEM_ATTRS (x) = 0; | |
945 | else | |
946 | { | |
947 | if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) | |
948 | { | |
949 | set_mem_alias_set (x, 0); | |
950 | set_mem_alias_set (y, 0); | |
951 | } | |
952 | ||
953 | if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y))) | |
954 | { | |
955 | set_mem_expr (x, 0); | |
956 | set_mem_expr (y, 0); | |
957 | set_mem_offset (x, 0); | |
958 | set_mem_offset (y, 0); | |
959 | } | |
960 | else if (MEM_OFFSET (x) != MEM_OFFSET (y)) | |
961 | { | |
962 | set_mem_offset (x, 0); | |
963 | set_mem_offset (y, 0); | |
964 | } | |
965 | ||
966 | set_mem_size (x, MAX (MEM_SIZE (x), MEM_SIZE (y))); | |
967 | set_mem_size (y, MEM_SIZE (x)); | |
968 | ||
969 | set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y))); | |
970 | set_mem_align (y, MEM_ALIGN (x)); | |
971 | } | |
972 | } | |
973 | ||
974 | fmt = GET_RTX_FORMAT (code); | |
975 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
976 | { | |
977 | switch (fmt[i]) | |
978 | { | |
979 | case 'E': | |
980 | /* Two vectors must have the same length. */ | |
981 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
982 | return; | |
983 | ||
984 | for (j = 0; j < XVECLEN (x, i); j++) | |
985 | merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j)); | |
986 | ||
987 | break; | |
988 | ||
989 | case 'e': | |
990 | merge_memattrs (XEXP (x, i), XEXP (y, i)); | |
991 | } | |
992 | } | |
993 | return; | |
994 | } | |
995 | ||
996 | ||
0dd0e980 JH |
997 | /* Return true if I1 and I2 are equivalent and thus can be crossjumped. */ |
998 | ||
999 | static bool | |
d329e058 | 1000 | insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2) |
0dd0e980 JH |
1001 | { |
1002 | rtx p1, p2; | |
1003 | ||
1004 | /* Verify that I1 and I2 are equivalent. */ | |
1005 | if (GET_CODE (i1) != GET_CODE (i2)) | |
1006 | return false; | |
1007 | ||
1008 | p1 = PATTERN (i1); | |
1009 | p2 = PATTERN (i2); | |
1010 | ||
1011 | if (GET_CODE (p1) != GET_CODE (p2)) | |
1012 | return false; | |
1013 | ||
1014 | /* If this is a CALL_INSN, compare register usage information. | |
1015 | If we don't check this on stack register machines, the two | |
1016 | CALL_INSNs might be merged leaving reg-stack.c with mismatching | |
1017 | numbers of stack registers in the same basic block. | |
1018 | If we don't check this on machines with delay slots, a delay slot may | |
1019 | be filled that clobbers a parameter expected by the subroutine. | |
1020 | ||
1021 | ??? We take the simple route for now and assume that if they're | |
1022 | equal, they were constructed identically. */ | |
1023 | ||
1024 | if (GET_CODE (i1) == CALL_INSN | |
db655634 JH |
1025 | && (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1), |
1026 | CALL_INSN_FUNCTION_USAGE (i2)) | |
1027 | || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2))) | |
0dd0e980 JH |
1028 | return false; |
1029 | ||
1030 | #ifdef STACK_REGS | |
1031 | /* If cross_jump_death_matters is not 0, the insn's mode | |
1032 | indicates whether or not the insn contains any stack-like | |
1033 | regs. */ | |
1034 | ||
1035 | if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1)) | |
1036 | { | |
1037 | /* If register stack conversion has already been done, then | |
1038 | death notes must also be compared before it is certain that | |
1039 | the two instruction streams match. */ | |
1040 | ||
1041 | rtx note; | |
1042 | HARD_REG_SET i1_regset, i2_regset; | |
1043 | ||
1044 | CLEAR_HARD_REG_SET (i1_regset); | |
1045 | CLEAR_HARD_REG_SET (i2_regset); | |
1046 | ||
1047 | for (note = REG_NOTES (i1); note; note = XEXP (note, 1)) | |
1048 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1049 | SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0))); | |
1050 | ||
1051 | for (note = REG_NOTES (i2); note; note = XEXP (note, 1)) | |
1052 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1053 | SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0))); | |
1054 | ||
1055 | GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done); | |
1056 | ||
1057 | return false; | |
1058 | ||
1059 | done: | |
1060 | ; | |
1061 | } | |
1062 | #endif | |
1063 | ||
1064 | if (reload_completed | |
3ce6bef0 RH |
1065 | ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2)) |
1066 | return true; | |
1067 | ||
1068 | /* Do not do EQUIV substitution after reload. First, we're undoing the | |
1069 | work of reload_cse. Second, we may be undoing the work of the post- | |
1070 | reload splitting pass. */ | |
1071 | /* ??? Possibly add a new phase switch variable that can be used by | |
1072 | targets to disallow the troublesome insns after splitting. */ | |
1073 | if (!reload_completed) | |
0dd0e980 JH |
1074 | { |
1075 | /* The following code helps take care of G++ cleanups. */ | |
1076 | rtx equiv1 = find_reg_equal_equiv_note (i1); | |
1077 | rtx equiv2 = find_reg_equal_equiv_note (i2); | |
1078 | ||
1079 | if (equiv1 && equiv2 | |
1080 | /* If the equivalences are not to a constant, they may | |
1081 | reference pseudos that no longer exist, so we can't | |
1082 | use them. */ | |
1083 | && (! reload_completed | |
1084 | || (CONSTANT_P (XEXP (equiv1, 0)) | |
1085 | && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0))))) | |
1086 | { | |
1087 | rtx s1 = single_set (i1); | |
1088 | rtx s2 = single_set (i2); | |
1089 | if (s1 != 0 && s2 != 0 | |
1090 | && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2))) | |
1091 | { | |
1092 | validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1); | |
1093 | validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1); | |
1094 | if (! rtx_renumbered_equal_p (p1, p2)) | |
1095 | cancel_changes (0); | |
1096 | else if (apply_change_group ()) | |
1097 | return true; | |
1098 | } | |
1099 | } | |
0dd0e980 | 1100 | } |
5f0d2358 | 1101 | |
3ce6bef0 | 1102 | return false; |
0dd0e980 JH |
1103 | } |
1104 | \f | |
402209ff JH |
1105 | /* Look through the insns at the end of BB1 and BB2 and find the longest |
1106 | sequence that are equivalent. Store the first insns for that sequence | |
1107 | in *F1 and *F2 and return the sequence length. | |
1108 | ||
1109 | To simplify callers of this function, if the blocks match exactly, | |
1110 | store the head of the blocks in *F1 and *F2. */ | |
1111 | ||
1112 | static int | |
d329e058 AJ |
1113 | flow_find_cross_jump (int mode ATTRIBUTE_UNUSED, basic_block bb1, |
1114 | basic_block bb2, rtx *f1, rtx *f2) | |
402209ff | 1115 | { |
0dd0e980 | 1116 | rtx i1, i2, last1, last2, afterlast1, afterlast2; |
402209ff JH |
1117 | int ninsns = 0; |
1118 | ||
1119 | /* Skip simple jumps at the end of the blocks. Complex jumps still | |
1120 | need to be compared for equivalence, which we'll do below. */ | |
1121 | ||
a813c111 | 1122 | i1 = BB_END (bb1); |
08f7f057 | 1123 | last1 = afterlast1 = last2 = afterlast2 = NULL_RTX; |
402209ff JH |
1124 | if (onlyjump_p (i1) |
1125 | || (returnjump_p (i1) && !side_effects_p (PATTERN (i1)))) | |
08f7f057 JH |
1126 | { |
1127 | last1 = i1; | |
08f7f057 JH |
1128 | i1 = PREV_INSN (i1); |
1129 | } | |
5f0d2358 | 1130 | |
a813c111 | 1131 | i2 = BB_END (bb2); |
402209ff JH |
1132 | if (onlyjump_p (i2) |
1133 | || (returnjump_p (i2) && !side_effects_p (PATTERN (i2)))) | |
08f7f057 JH |
1134 | { |
1135 | last2 = i2; | |
d1ee6d9b JH |
1136 | /* Count everything except for unconditional jump as insn. */ |
1137 | if (!simplejump_p (i2) && !returnjump_p (i2) && last1) | |
1138 | ninsns++; | |
08f7f057 JH |
1139 | i2 = PREV_INSN (i2); |
1140 | } | |
402209ff | 1141 | |
402209ff JH |
1142 | while (true) |
1143 | { | |
1144 | /* Ignore notes. */ | |
a813c111 | 1145 | while (!INSN_P (i1) && i1 != BB_HEAD (bb1)) |
402209ff | 1146 | i1 = PREV_INSN (i1); |
5f0d2358 | 1147 | |
a813c111 | 1148 | while (!INSN_P (i2) && i2 != BB_HEAD (bb2)) |
402209ff JH |
1149 | i2 = PREV_INSN (i2); |
1150 | ||
a813c111 | 1151 | if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2)) |
402209ff JH |
1152 | break; |
1153 | ||
0dd0e980 | 1154 | if (!insns_match_p (mode, i1, i2)) |
402209ff JH |
1155 | break; |
1156 | ||
2b3493c8 AK |
1157 | merge_memattrs (i1, i2); |
1158 | ||
dd4ff203 RK |
1159 | /* Don't begin a cross-jump with a NOTE insn. */ |
1160 | if (INSN_P (i1)) | |
402209ff | 1161 | { |
7106d491 RE |
1162 | /* If the merged insns have different REG_EQUAL notes, then |
1163 | remove them. */ | |
1164 | rtx equiv1 = find_reg_equal_equiv_note (i1); | |
1165 | rtx equiv2 = find_reg_equal_equiv_note (i2); | |
1166 | ||
1167 | if (equiv1 && !equiv2) | |
1168 | remove_note (i1, equiv1); | |
1169 | else if (!equiv1 && equiv2) | |
1170 | remove_note (i2, equiv2); | |
1171 | else if (equiv1 && equiv2 | |
1172 | && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0))) | |
1173 | { | |
1174 | remove_note (i1, equiv1); | |
1175 | remove_note (i2, equiv2); | |
1176 | } | |
f87c27b4 | 1177 | |
402209ff JH |
1178 | afterlast1 = last1, afterlast2 = last2; |
1179 | last1 = i1, last2 = i2; | |
f87c27b4 | 1180 | ninsns++; |
402209ff | 1181 | } |
5f0d2358 | 1182 | |
402209ff JH |
1183 | i1 = PREV_INSN (i1); |
1184 | i2 = PREV_INSN (i2); | |
1185 | } | |
1186 | ||
1187 | #ifdef HAVE_cc0 | |
5f0d2358 RK |
1188 | /* Don't allow the insn after a compare to be shared by |
1189 | cross-jumping unless the compare is also shared. */ | |
1190 | if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1)) | |
1191 | last1 = afterlast1, last2 = afterlast2, ninsns--; | |
402209ff JH |
1192 | #endif |
1193 | ||
eaec9b3d | 1194 | /* Include preceding notes and labels in the cross-jump. One, |
402209ff JH |
1195 | this may bring us to the head of the blocks as requested above. |
1196 | Two, it keeps line number notes as matched as may be. */ | |
1197 | if (ninsns) | |
1198 | { | |
a813c111 | 1199 | while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1))) |
402209ff | 1200 | last1 = PREV_INSN (last1); |
5f0d2358 | 1201 | |
a813c111 | 1202 | if (last1 != BB_HEAD (bb1) && GET_CODE (PREV_INSN (last1)) == CODE_LABEL) |
402209ff | 1203 | last1 = PREV_INSN (last1); |
5f0d2358 | 1204 | |
a813c111 | 1205 | while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2))) |
402209ff | 1206 | last2 = PREV_INSN (last2); |
5f0d2358 | 1207 | |
a813c111 | 1208 | if (last2 != BB_HEAD (bb2) && GET_CODE (PREV_INSN (last2)) == CODE_LABEL) |
402209ff JH |
1209 | last2 = PREV_INSN (last2); |
1210 | ||
1211 | *f1 = last1; | |
1212 | *f2 = last2; | |
1213 | } | |
1214 | ||
1215 | return ninsns; | |
1216 | } | |
1217 | ||
1218 | /* Return true iff outgoing edges of BB1 and BB2 match, together with | |
1219 | the branch instruction. This means that if we commonize the control | |
1220 | flow before end of the basic block, the semantic remains unchanged. | |
1221 | ||
1222 | We may assume that there exists one edge with a common destination. */ | |
1223 | ||
1224 | static bool | |
d329e058 | 1225 | outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) |
402209ff | 1226 | { |
0dd0e980 JH |
1227 | int nehedges1 = 0, nehedges2 = 0; |
1228 | edge fallthru1 = 0, fallthru2 = 0; | |
1229 | edge e1, e2; | |
1230 | ||
c04cf67b RH |
1231 | /* If BB1 has only one successor, we may be looking at either an |
1232 | unconditional jump, or a fake edge to exit. */ | |
d1ee6d9b | 1233 | if (bb1->succ && !bb1->succ->succ_next |
ffc8f11e | 1234 | && (bb1->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0 |
a813c111 | 1235 | && (GET_CODE (BB_END (bb1)) != JUMP_INSN || simplejump_p (BB_END (bb1)))) |
5f0d2358 | 1236 | return (bb2->succ && !bb2->succ->succ_next |
ffc8f11e | 1237 | && (bb2->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0 |
a813c111 | 1238 | && (GET_CODE (BB_END (bb2)) != JUMP_INSN || simplejump_p (BB_END (bb2)))); |
402209ff JH |
1239 | |
1240 | /* Match conditional jumps - this may get tricky when fallthru and branch | |
1241 | edges are crossed. */ | |
1242 | if (bb1->succ | |
1243 | && bb1->succ->succ_next | |
1244 | && !bb1->succ->succ_next->succ_next | |
a813c111 SB |
1245 | && any_condjump_p (BB_END (bb1)) |
1246 | && onlyjump_p (BB_END (bb1))) | |
402209ff JH |
1247 | { |
1248 | edge b1, f1, b2, f2; | |
1249 | bool reverse, match; | |
1250 | rtx set1, set2, cond1, cond2; | |
1251 | enum rtx_code code1, code2; | |
1252 | ||
1253 | if (!bb2->succ | |
f87c27b4 | 1254 | || !bb2->succ->succ_next |
0a2ed1f1 | 1255 | || bb2->succ->succ_next->succ_next |
a813c111 SB |
1256 | || !any_condjump_p (BB_END (bb2)) |
1257 | || !onlyjump_p (BB_END (bb2))) | |
0a2ed1f1 JH |
1258 | return false; |
1259 | ||
402209ff JH |
1260 | b1 = BRANCH_EDGE (bb1); |
1261 | b2 = BRANCH_EDGE (bb2); | |
1262 | f1 = FALLTHRU_EDGE (bb1); | |
1263 | f2 = FALLTHRU_EDGE (bb2); | |
1264 | ||
1265 | /* Get around possible forwarders on fallthru edges. Other cases | |
1266 | should be optimized out already. */ | |
635559ab | 1267 | if (FORWARDER_BLOCK_P (f1->dest)) |
402209ff | 1268 | f1 = f1->dest->succ; |
5f0d2358 | 1269 | |
635559ab | 1270 | if (FORWARDER_BLOCK_P (f2->dest)) |
402209ff JH |
1271 | f2 = f2->dest->succ; |
1272 | ||
1273 | /* To simplify use of this function, return false if there are | |
1274 | unneeded forwarder blocks. These will get eliminated later | |
1275 | during cleanup_cfg. */ | |
635559ab JH |
1276 | if (FORWARDER_BLOCK_P (f1->dest) |
1277 | || FORWARDER_BLOCK_P (f2->dest) | |
1278 | || FORWARDER_BLOCK_P (b1->dest) | |
1279 | || FORWARDER_BLOCK_P (b2->dest)) | |
402209ff JH |
1280 | return false; |
1281 | ||
1282 | if (f1->dest == f2->dest && b1->dest == b2->dest) | |
1283 | reverse = false; | |
1284 | else if (f1->dest == b2->dest && b1->dest == f2->dest) | |
1285 | reverse = true; | |
1286 | else | |
1287 | return false; | |
1288 | ||
a813c111 SB |
1289 | set1 = pc_set (BB_END (bb1)); |
1290 | set2 = pc_set (BB_END (bb2)); | |
402209ff JH |
1291 | if ((XEXP (SET_SRC (set1), 1) == pc_rtx) |
1292 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) | |
1293 | reverse = !reverse; | |
1294 | ||
1295 | cond1 = XEXP (SET_SRC (set1), 0); | |
1296 | cond2 = XEXP (SET_SRC (set2), 0); | |
1297 | code1 = GET_CODE (cond1); | |
1298 | if (reverse) | |
a813c111 | 1299 | code2 = reversed_comparison_code (cond2, BB_END (bb2)); |
402209ff JH |
1300 | else |
1301 | code2 = GET_CODE (cond2); | |
5f0d2358 | 1302 | |
402209ff JH |
1303 | if (code2 == UNKNOWN) |
1304 | return false; | |
1305 | ||
1306 | /* Verify codes and operands match. */ | |
1307 | match = ((code1 == code2 | |
1308 | && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
1309 | && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
1310 | || (code1 == swap_condition (code2) | |
1311 | && rtx_renumbered_equal_p (XEXP (cond1, 1), | |
1312 | XEXP (cond2, 0)) | |
1313 | && rtx_renumbered_equal_p (XEXP (cond1, 0), | |
1314 | XEXP (cond2, 1)))); | |
1315 | ||
1316 | /* If we return true, we will join the blocks. Which means that | |
1317 | we will only have one branch prediction bit to work with. Thus | |
1318 | we require the existing branches to have probabilities that are | |
1319 | roughly similar. */ | |
b446e5a2 JH |
1320 | if (match |
1321 | && !optimize_size | |
194734e9 JH |
1322 | && maybe_hot_bb_p (bb1) |
1323 | && maybe_hot_bb_p (bb2)) | |
402209ff | 1324 | { |
b446e5a2 | 1325 | int prob2; |
5f0d2358 | 1326 | |
b446e5a2 JH |
1327 | if (b1->dest == b2->dest) |
1328 | prob2 = b2->probability; | |
1329 | else | |
1330 | /* Do not use f2 probability as f2 may be forwarded. */ | |
1331 | prob2 = REG_BR_PROB_BASE - b2->probability; | |
402209ff | 1332 | |
0a2ed1f1 JH |
1333 | /* Fail if the difference in probabilities is greater than 50%. |
1334 | This rules out two well-predicted branches with opposite | |
1335 | outcomes. */ | |
7225b8ec | 1336 | if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2) |
402209ff | 1337 | { |
c263766c RH |
1338 | if (dump_file) |
1339 | fprintf (dump_file, | |
b446e5a2 | 1340 | "Outcomes of branch in bb %i and %i differs to much (%i %i)\n", |
0b17ab2f | 1341 | bb1->index, bb2->index, b1->probability, prob2); |
5f0d2358 | 1342 | |
b446e5a2 JH |
1343 | return false; |
1344 | } | |
402209ff JH |
1345 | } |
1346 | ||
c263766c RH |
1347 | if (dump_file && match) |
1348 | fprintf (dump_file, "Conditionals in bb %i and %i match.\n", | |
0b17ab2f | 1349 | bb1->index, bb2->index); |
402209ff JH |
1350 | |
1351 | return match; | |
1352 | } | |
1353 | ||
09da1532 | 1354 | /* Generic case - we are seeing a computed jump, table jump or trapping |
0dd0e980 JH |
1355 | instruction. */ |
1356 | ||
39811184 JZ |
1357 | #ifndef CASE_DROPS_THROUGH |
1358 | /* Check whether there are tablejumps in the end of BB1 and BB2. | |
1359 | Return true if they are identical. */ | |
1360 | { | |
1361 | rtx label1, label2; | |
1362 | rtx table1, table2; | |
1363 | ||
a813c111 SB |
1364 | if (tablejump_p (BB_END (bb1), &label1, &table1) |
1365 | && tablejump_p (BB_END (bb2), &label2, &table2) | |
39811184 JZ |
1366 | && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2))) |
1367 | { | |
1368 | /* The labels should never be the same rtx. If they really are same | |
1369 | the jump tables are same too. So disable crossjumping of blocks BB1 | |
1370 | and BB2 because when deleting the common insns in the end of BB1 | |
6de9cd9a | 1371 | by delete_basic_block () the jump table would be deleted too. */ |
4af16369 | 1372 | /* If LABEL2 is referenced in BB1->END do not do anything |
39811184 JZ |
1373 | because we would loose information when replacing |
1374 | LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */ | |
a813c111 | 1375 | if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1))) |
39811184 JZ |
1376 | { |
1377 | /* Set IDENTICAL to true when the tables are identical. */ | |
1378 | bool identical = false; | |
1379 | rtx p1, p2; | |
1380 | ||
1381 | p1 = PATTERN (table1); | |
1382 | p2 = PATTERN (table2); | |
1383 | if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2)) | |
1384 | { | |
1385 | identical = true; | |
1386 | } | |
1387 | else if (GET_CODE (p1) == ADDR_DIFF_VEC | |
1388 | && (XVECLEN (p1, 1) == XVECLEN (p2, 1)) | |
1389 | && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2)) | |
1390 | && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3))) | |
1391 | { | |
1392 | int i; | |
1393 | ||
1394 | identical = true; | |
1395 | for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--) | |
1396 | if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i))) | |
1397 | identical = false; | |
1398 | } | |
1399 | ||
1400 | if (identical) | |
1401 | { | |
4af16369 | 1402 | replace_label_data rr; |
39811184 JZ |
1403 | bool match; |
1404 | ||
1405 | /* Temporarily replace references to LABEL1 with LABEL2 | |
1406 | in BB1->END so that we could compare the instructions. */ | |
1407 | rr.r1 = label1; | |
1408 | rr.r2 = label2; | |
4af16369 | 1409 | rr.update_label_nuses = false; |
a813c111 | 1410 | for_each_rtx (&BB_END (bb1), replace_label, &rr); |
39811184 | 1411 | |
a813c111 | 1412 | match = insns_match_p (mode, BB_END (bb1), BB_END (bb2)); |
c263766c RH |
1413 | if (dump_file && match) |
1414 | fprintf (dump_file, | |
39811184 JZ |
1415 | "Tablejumps in bb %i and %i match.\n", |
1416 | bb1->index, bb2->index); | |
1417 | ||
1418 | /* Set the original label in BB1->END because when deleting | |
1419 | a block whose end is a tablejump, the tablejump referenced | |
1420 | from the instruction is deleted too. */ | |
1421 | rr.r1 = label2; | |
1422 | rr.r2 = label1; | |
a813c111 | 1423 | for_each_rtx (&BB_END (bb1), replace_label, &rr); |
39811184 JZ |
1424 | |
1425 | return match; | |
1426 | } | |
1427 | } | |
1428 | return false; | |
1429 | } | |
1430 | } | |
1431 | #endif | |
1432 | ||
0dd0e980 | 1433 | /* First ensure that the instructions match. There may be many outgoing |
39811184 | 1434 | edges so this test is generally cheaper. */ |
a813c111 | 1435 | if (!insns_match_p (mode, BB_END (bb1), BB_END (bb2))) |
0dd0e980 JH |
1436 | return false; |
1437 | ||
1438 | /* Search the outgoing edges, ensure that the counts do match, find possible | |
1439 | fallthru and exception handling edges since these needs more | |
1440 | validation. */ | |
1441 | for (e1 = bb1->succ, e2 = bb2->succ; e1 && e2; | |
1442 | e1 = e1->succ_next, e2 = e2->succ_next) | |
1443 | { | |
1444 | if (e1->flags & EDGE_EH) | |
1445 | nehedges1++; | |
5f0d2358 | 1446 | |
0dd0e980 JH |
1447 | if (e2->flags & EDGE_EH) |
1448 | nehedges2++; | |
5f0d2358 | 1449 | |
0dd0e980 JH |
1450 | if (e1->flags & EDGE_FALLTHRU) |
1451 | fallthru1 = e1; | |
1452 | if (e2->flags & EDGE_FALLTHRU) | |
1453 | fallthru2 = e2; | |
1454 | } | |
5f0d2358 | 1455 | |
0dd0e980 | 1456 | /* If number of edges of various types does not match, fail. */ |
5f0d2358 RK |
1457 | if (e1 || e2 |
1458 | || nehedges1 != nehedges2 | |
1459 | || (fallthru1 != 0) != (fallthru2 != 0)) | |
0dd0e980 JH |
1460 | return false; |
1461 | ||
1462 | /* fallthru edges must be forwarded to the same destination. */ | |
1463 | if (fallthru1) | |
1464 | { | |
1465 | basic_block d1 = (forwarder_block_p (fallthru1->dest) | |
f87c27b4 | 1466 | ? fallthru1->dest->succ->dest: fallthru1->dest); |
0dd0e980 | 1467 | basic_block d2 = (forwarder_block_p (fallthru2->dest) |
f87c27b4 | 1468 | ? fallthru2->dest->succ->dest: fallthru2->dest); |
5f0d2358 | 1469 | |
0dd0e980 JH |
1470 | if (d1 != d2) |
1471 | return false; | |
1472 | } | |
5f0d2358 | 1473 | |
5f77fbd4 JJ |
1474 | /* Ensure the same EH region. */ |
1475 | { | |
a813c111 SB |
1476 | rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0); |
1477 | rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0); | |
5f0d2358 | 1478 | |
5f77fbd4 JJ |
1479 | if (!n1 && n2) |
1480 | return false; | |
1481 | ||
1482 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
1483 | return false; | |
1484 | } | |
5f0d2358 | 1485 | |
e0bb17a8 | 1486 | /* We don't need to match the rest of edges as above checks should be enough |
0dd0e980 JH |
1487 | to ensure that they are equivalent. */ |
1488 | return true; | |
402209ff JH |
1489 | } |
1490 | ||
1491 | /* E1 and E2 are edges with the same destination block. Search their | |
1492 | predecessors for common code. If found, redirect control flow from | |
1493 | (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */ | |
1494 | ||
1495 | static bool | |
d329e058 | 1496 | try_crossjump_to_edge (int mode, edge e1, edge e2) |
402209ff JH |
1497 | { |
1498 | int nmatch; | |
1499 | basic_block src1 = e1->src, src2 = e2->src; | |
39587bb9 | 1500 | basic_block redirect_to, redirect_from, to_remove; |
402209ff JH |
1501 | rtx newpos1, newpos2; |
1502 | edge s; | |
402209ff | 1503 | |
6de9cd9a DN |
1504 | newpos1 = newpos2 = NULL_RTX; |
1505 | ||
750054a2 CT |
1506 | /* If we have partitioned hot/cold basic blocks, it is a bad idea |
1507 | to try this optimization. */ | |
1508 | ||
1509 | if (flag_reorder_blocks_and_partition && no_new_pseudos) | |
1510 | return false; | |
1511 | ||
402209ff JH |
1512 | /* Search backward through forwarder blocks. We don't need to worry |
1513 | about multiple entry or chained forwarders, as they will be optimized | |
1514 | away. We do this to look past the unconditional jump following a | |
1515 | conditional jump that is required due to the current CFG shape. */ | |
1516 | if (src1->pred | |
1517 | && !src1->pred->pred_next | |
635559ab | 1518 | && FORWARDER_BLOCK_P (src1)) |
5f0d2358 RK |
1519 | e1 = src1->pred, src1 = e1->src; |
1520 | ||
402209ff JH |
1521 | if (src2->pred |
1522 | && !src2->pred->pred_next | |
635559ab | 1523 | && FORWARDER_BLOCK_P (src2)) |
5f0d2358 | 1524 | e2 = src2->pred, src2 = e2->src; |
402209ff JH |
1525 | |
1526 | /* Nothing to do if we reach ENTRY, or a common source block. */ | |
1527 | if (src1 == ENTRY_BLOCK_PTR || src2 == ENTRY_BLOCK_PTR) | |
1528 | return false; | |
1529 | if (src1 == src2) | |
1530 | return false; | |
1531 | ||
1532 | /* Seeing more than 1 forwarder blocks would confuse us later... */ | |
635559ab JH |
1533 | if (FORWARDER_BLOCK_P (e1->dest) |
1534 | && FORWARDER_BLOCK_P (e1->dest->succ->dest)) | |
402209ff | 1535 | return false; |
5f0d2358 | 1536 | |
635559ab JH |
1537 | if (FORWARDER_BLOCK_P (e2->dest) |
1538 | && FORWARDER_BLOCK_P (e2->dest->succ->dest)) | |
402209ff JH |
1539 | return false; |
1540 | ||
1541 | /* Likewise with dead code (possibly newly created by the other optimizations | |
1542 | of cfg_cleanup). */ | |
1543 | if (!src1->pred || !src2->pred) | |
1544 | return false; | |
1545 | ||
402209ff | 1546 | /* Look for the common insn sequence, part the first ... */ |
0dd0e980 | 1547 | if (!outgoing_edges_match (mode, src1, src2)) |
402209ff JH |
1548 | return false; |
1549 | ||
1550 | /* ... and part the second. */ | |
1551 | nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2); | |
1552 | if (!nmatch) | |
1553 | return false; | |
1554 | ||
39811184 JZ |
1555 | #ifndef CASE_DROPS_THROUGH |
1556 | /* Here we know that the insns in the end of SRC1 which are common with SRC2 | |
1557 | will be deleted. | |
1558 | If we have tablejumps in the end of SRC1 and SRC2 | |
1559 | they have been already compared for equivalence in outgoing_edges_match () | |
1560 | so replace the references to TABLE1 by references to TABLE2. */ | |
1561 | { | |
1562 | rtx label1, label2; | |
1563 | rtx table1, table2; | |
1564 | ||
a813c111 SB |
1565 | if (tablejump_p (BB_END (src1), &label1, &table1) |
1566 | && tablejump_p (BB_END (src2), &label2, &table2) | |
39811184 JZ |
1567 | && label1 != label2) |
1568 | { | |
4af16369 | 1569 | replace_label_data rr; |
39811184 JZ |
1570 | rtx insn; |
1571 | ||
1572 | /* Replace references to LABEL1 with LABEL2. */ | |
1573 | rr.r1 = label1; | |
1574 | rr.r2 = label2; | |
4af16369 | 1575 | rr.update_label_nuses = true; |
39811184 JZ |
1576 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
1577 | { | |
1578 | /* Do not replace the label in SRC1->END because when deleting | |
1579 | a block whose end is a tablejump, the tablejump referenced | |
1580 | from the instruction is deleted too. */ | |
a813c111 | 1581 | if (insn != BB_END (src1)) |
39811184 JZ |
1582 | for_each_rtx (&insn, replace_label, &rr); |
1583 | } | |
1584 | } | |
1585 | } | |
1586 | #endif | |
10d6c0d0 | 1587 | |
402209ff | 1588 | /* Avoid splitting if possible. */ |
a813c111 | 1589 | if (newpos2 == BB_HEAD (src2)) |
402209ff JH |
1590 | redirect_to = src2; |
1591 | else | |
1592 | { | |
c263766c RH |
1593 | if (dump_file) |
1594 | fprintf (dump_file, "Splitting bb %i before %i insns\n", | |
0b17ab2f | 1595 | src2->index, nmatch); |
402209ff JH |
1596 | redirect_to = split_block (src2, PREV_INSN (newpos2))->dest; |
1597 | } | |
1598 | ||
c263766c RH |
1599 | if (dump_file) |
1600 | fprintf (dump_file, | |
402209ff | 1601 | "Cross jumping from bb %i to bb %i; %i common insns\n", |
0b17ab2f | 1602 | src1->index, src2->index, nmatch); |
402209ff JH |
1603 | |
1604 | redirect_to->count += src1->count; | |
1605 | redirect_to->frequency += src1->frequency; | |
2ca6672b JH |
1606 | /* We may have some registers visible trought the block. */ |
1607 | redirect_to->flags |= BB_DIRTY; | |
402209ff JH |
1608 | |
1609 | /* Recompute the frequencies and counts of outgoing edges. */ | |
1610 | for (s = redirect_to->succ; s; s = s->succ_next) | |
1611 | { | |
1612 | edge s2; | |
1613 | basic_block d = s->dest; | |
1614 | ||
635559ab | 1615 | if (FORWARDER_BLOCK_P (d)) |
402209ff | 1616 | d = d->succ->dest; |
5f0d2358 | 1617 | |
402209ff JH |
1618 | for (s2 = src1->succ; ; s2 = s2->succ_next) |
1619 | { | |
1620 | basic_block d2 = s2->dest; | |
635559ab | 1621 | if (FORWARDER_BLOCK_P (d2)) |
402209ff JH |
1622 | d2 = d2->succ->dest; |
1623 | if (d == d2) | |
1624 | break; | |
1625 | } | |
5f0d2358 | 1626 | |
402209ff JH |
1627 | s->count += s2->count; |
1628 | ||
1629 | /* Take care to update possible forwarder blocks. We verified | |
1630 | that there is no more than one in the chain, so we can't run | |
1631 | into infinite loop. */ | |
635559ab | 1632 | if (FORWARDER_BLOCK_P (s->dest)) |
402209ff JH |
1633 | { |
1634 | s->dest->succ->count += s2->count; | |
1635 | s->dest->count += s2->count; | |
1636 | s->dest->frequency += EDGE_FREQUENCY (s); | |
1637 | } | |
5f0d2358 | 1638 | |
635559ab | 1639 | if (FORWARDER_BLOCK_P (s2->dest)) |
402209ff JH |
1640 | { |
1641 | s2->dest->succ->count -= s2->count; | |
b446e5a2 JH |
1642 | if (s2->dest->succ->count < 0) |
1643 | s2->dest->succ->count = 0; | |
402209ff JH |
1644 | s2->dest->count -= s2->count; |
1645 | s2->dest->frequency -= EDGE_FREQUENCY (s); | |
b446e5a2 JH |
1646 | if (s2->dest->frequency < 0) |
1647 | s2->dest->frequency = 0; | |
1648 | if (s2->dest->count < 0) | |
1649 | s2->dest->count = 0; | |
402209ff | 1650 | } |
5f0d2358 | 1651 | |
402209ff JH |
1652 | if (!redirect_to->frequency && !src1->frequency) |
1653 | s->probability = (s->probability + s2->probability) / 2; | |
1654 | else | |
5f0d2358 RK |
1655 | s->probability |
1656 | = ((s->probability * redirect_to->frequency + | |
1657 | s2->probability * src1->frequency) | |
1658 | / (redirect_to->frequency + src1->frequency)); | |
402209ff JH |
1659 | } |
1660 | ||
b446e5a2 | 1661 | update_br_prob_note (redirect_to); |
402209ff JH |
1662 | |
1663 | /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */ | |
1664 | ||
1665 | /* Skip possible basic block header. */ | |
1666 | if (GET_CODE (newpos1) == CODE_LABEL) | |
1667 | newpos1 = NEXT_INSN (newpos1); | |
5f0d2358 | 1668 | |
402209ff JH |
1669 | if (GET_CODE (newpos1) == NOTE) |
1670 | newpos1 = NEXT_INSN (newpos1); | |
402209ff | 1671 | |
39587bb9 ZD |
1672 | redirect_from = split_block (src1, PREV_INSN (newpos1))->src; |
1673 | to_remove = redirect_from->succ->dest; | |
402209ff | 1674 | |
39587bb9 | 1675 | redirect_edge_and_branch_force (redirect_from->succ, redirect_to); |
f470c378 | 1676 | delete_basic_block (to_remove); |
402209ff | 1677 | |
39587bb9 | 1678 | update_forwarder_flag (redirect_from); |
635559ab | 1679 | |
402209ff JH |
1680 | return true; |
1681 | } | |
1682 | ||
1683 | /* Search the predecessors of BB for common insn sequences. When found, | |
1684 | share code between them by redirecting control flow. Return true if | |
1685 | any changes made. */ | |
1686 | ||
1687 | static bool | |
d329e058 | 1688 | try_crossjump_bb (int mode, basic_block bb) |
402209ff JH |
1689 | { |
1690 | edge e, e2, nexte2, nexte, fallthru; | |
1691 | bool changed; | |
5f24e0dc | 1692 | int n = 0, max; |
402209ff | 1693 | |
f63d1bf7 | 1694 | /* Nothing to do if there is not at least two incoming edges. */ |
402209ff JH |
1695 | if (!bb->pred || !bb->pred->pred_next) |
1696 | return false; | |
1697 | ||
750054a2 CT |
1698 | /* If we are partitioning hot/cold basic blocks, we don't want to |
1699 | mess up unconditional or indirect jumps that cross between hot | |
1700 | and cold sections. */ | |
1701 | ||
1702 | if (flag_reorder_blocks_and_partition | |
1703 | && (bb->pred->src->partition != bb->pred->pred_next->src->partition | |
1704 | || bb->pred->crossing_edge)) | |
1705 | return false; | |
1706 | ||
402209ff JH |
1707 | /* It is always cheapest to redirect a block that ends in a branch to |
1708 | a block that falls through into BB, as that adds no branches to the | |
1709 | program. We'll try that combination first. */ | |
5f24e0dc RH |
1710 | fallthru = NULL; |
1711 | max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES); | |
1712 | for (e = bb->pred; e ; e = e->pred_next, n++) | |
f5eb5fd0 | 1713 | { |
5f24e0dc RH |
1714 | if (e->flags & EDGE_FALLTHRU) |
1715 | fallthru = e; | |
1716 | if (n > max) | |
f5eb5fd0 JH |
1717 | return false; |
1718 | } | |
402209ff JH |
1719 | |
1720 | changed = false; | |
1721 | for (e = bb->pred; e; e = nexte) | |
1722 | { | |
1723 | nexte = e->pred_next; | |
1724 | ||
402209ff JH |
1725 | /* As noted above, first try with the fallthru predecessor. */ |
1726 | if (fallthru) | |
1727 | { | |
1728 | /* Don't combine the fallthru edge into anything else. | |
1729 | If there is a match, we'll do it the other way around. */ | |
1730 | if (e == fallthru) | |
1731 | continue; | |
7cf240d5 JH |
1732 | /* If nothing changed since the last attempt, there is nothing |
1733 | we can do. */ | |
1734 | if (!first_pass | |
1735 | && (!(e->src->flags & BB_DIRTY) | |
1736 | && !(fallthru->src->flags & BB_DIRTY))) | |
1737 | continue; | |
402209ff JH |
1738 | |
1739 | if (try_crossjump_to_edge (mode, e, fallthru)) | |
1740 | { | |
1741 | changed = true; | |
1742 | nexte = bb->pred; | |
1743 | continue; | |
1744 | } | |
1745 | } | |
1746 | ||
1747 | /* Non-obvious work limiting check: Recognize that we're going | |
1748 | to call try_crossjump_bb on every basic block. So if we have | |
1749 | two blocks with lots of outgoing edges (a switch) and they | |
1750 | share lots of common destinations, then we would do the | |
1751 | cross-jump check once for each common destination. | |
1752 | ||
1753 | Now, if the blocks actually are cross-jump candidates, then | |
1754 | all of their destinations will be shared. Which means that | |
1755 | we only need check them for cross-jump candidacy once. We | |
1756 | can eliminate redundant checks of crossjump(A,B) by arbitrarily | |
1757 | choosing to do the check from the block for which the edge | |
1758 | in question is the first successor of A. */ | |
1759 | if (e->src->succ != e) | |
1760 | continue; | |
1761 | ||
1762 | for (e2 = bb->pred; e2; e2 = nexte2) | |
1763 | { | |
1764 | nexte2 = e2->pred_next; | |
1765 | ||
1766 | if (e2 == e) | |
1767 | continue; | |
1768 | ||
1769 | /* We've already checked the fallthru edge above. */ | |
1770 | if (e2 == fallthru) | |
1771 | continue; | |
1772 | ||
402209ff JH |
1773 | /* The "first successor" check above only prevents multiple |
1774 | checks of crossjump(A,B). In order to prevent redundant | |
1775 | checks of crossjump(B,A), require that A be the block | |
1776 | with the lowest index. */ | |
0b17ab2f | 1777 | if (e->src->index > e2->src->index) |
402209ff JH |
1778 | continue; |
1779 | ||
7cf240d5 JH |
1780 | /* If nothing changed since the last attempt, there is nothing |
1781 | we can do. */ | |
1782 | if (!first_pass | |
1783 | && (!(e->src->flags & BB_DIRTY) | |
1784 | && !(e2->src->flags & BB_DIRTY))) | |
1785 | continue; | |
1786 | ||
402209ff JH |
1787 | if (try_crossjump_to_edge (mode, e, e2)) |
1788 | { | |
1789 | changed = true; | |
1790 | nexte = bb->pred; | |
1791 | break; | |
1792 | } | |
1793 | } | |
1794 | } | |
1795 | ||
1796 | return changed; | |
1797 | } | |
1798 | ||
1799 | /* Do simple CFG optimizations - basic block merging, simplifying of jump | |
1800 | instructions etc. Return nonzero if changes were made. */ | |
1801 | ||
1802 | static bool | |
d329e058 | 1803 | try_optimize_cfg (int mode) |
402209ff | 1804 | { |
402209ff JH |
1805 | bool changed_overall = false; |
1806 | bool changed; | |
1807 | int iterations = 0; | |
ec3ae3da | 1808 | basic_block bb, b, next; |
402209ff | 1809 | |
ca6c03ca JH |
1810 | if (mode & CLEANUP_CROSSJUMP) |
1811 | add_noreturn_fake_exit_edges (); | |
1812 | ||
e0082a72 ZD |
1813 | FOR_EACH_BB (bb) |
1814 | update_forwarder_flag (bb); | |
635559ab | 1815 | |
7cf240d5 | 1816 | if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING)) |
38c1593d JH |
1817 | clear_bb_flags (); |
1818 | ||
245f1bfa | 1819 | if (! targetm.cannot_modify_jumps_p ()) |
402209ff | 1820 | { |
7cf240d5 | 1821 | first_pass = true; |
e4ec2cac AO |
1822 | /* Attempt to merge blocks as made possible by edge removal. If |
1823 | a block has only one successor, and the successor has only | |
1824 | one predecessor, they may be combined. */ | |
1825 | do | |
402209ff | 1826 | { |
e4ec2cac AO |
1827 | changed = false; |
1828 | iterations++; | |
1829 | ||
c263766c RH |
1830 | if (dump_file) |
1831 | fprintf (dump_file, | |
e4ec2cac AO |
1832 | "\n\ntry_optimize_cfg iteration %i\n\n", |
1833 | iterations); | |
402209ff | 1834 | |
e0082a72 | 1835 | for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR;) |
402209ff | 1836 | { |
e0082a72 | 1837 | basic_block c; |
e4ec2cac AO |
1838 | edge s; |
1839 | bool changed_here = false; | |
5f0d2358 | 1840 | |
e4ec2cac AO |
1841 | /* Delete trivially dead basic blocks. */ |
1842 | while (b->pred == NULL) | |
1843 | { | |
f6366fc7 | 1844 | c = b->prev_bb; |
c263766c RH |
1845 | if (dump_file) |
1846 | fprintf (dump_file, "Deleting block %i.\n", | |
0b17ab2f | 1847 | b->index); |
e4ec2cac | 1848 | |
f470c378 | 1849 | delete_basic_block (b); |
bc35512f JH |
1850 | if (!(mode & CLEANUP_CFGLAYOUT)) |
1851 | changed = true; | |
e4ec2cac AO |
1852 | b = c; |
1853 | } | |
402209ff | 1854 | |
e4ec2cac AO |
1855 | /* Remove code labels no longer used. Don't do this |
1856 | before CALL_PLACEHOLDER is removed, as some branches | |
1857 | may be hidden within. */ | |
1858 | if (b->pred->pred_next == NULL | |
1859 | && (b->pred->flags & EDGE_FALLTHRU) | |
1860 | && !(b->pred->flags & EDGE_COMPLEX) | |
a813c111 | 1861 | && GET_CODE (BB_HEAD (b)) == CODE_LABEL |
e4ec2cac | 1862 | && (!(mode & CLEANUP_PRE_SIBCALL) |
a813c111 | 1863 | || !tail_recursion_label_p (BB_HEAD (b))) |
e4ec2cac AO |
1864 | /* If the previous block ends with a branch to this |
1865 | block, we can't delete the label. Normally this | |
1866 | is a condjump that is yet to be simplified, but | |
1867 | if CASE_DROPS_THRU, this can be a tablejump with | |
1868 | some element going to the same place as the | |
1869 | default (fallthru). */ | |
1870 | && (b->pred->src == ENTRY_BLOCK_PTR | |
a813c111 SB |
1871 | || GET_CODE (BB_END (b->pred->src)) != JUMP_INSN |
1872 | || ! label_is_jump_target_p (BB_HEAD (b), | |
1873 | BB_END (b->pred->src)))) | |
e4ec2cac | 1874 | { |
a813c111 | 1875 | rtx label = BB_HEAD (b); |
5f0d2358 | 1876 | |
e4ec2cac | 1877 | delete_insn_chain (label, label); |
bc35512f JH |
1878 | /* In the case label is undeletable, move it after the |
1879 | BASIC_BLOCK note. */ | |
a813c111 | 1880 | if (NOTE_LINE_NUMBER (BB_HEAD (b)) == NOTE_INSN_DELETED_LABEL) |
bc35512f | 1881 | { |
a813c111 | 1882 | rtx bb_note = NEXT_INSN (BB_HEAD (b)); |
bc35512f JH |
1883 | |
1884 | reorder_insns_nobb (label, label, bb_note); | |
a813c111 | 1885 | BB_HEAD (b) = bb_note; |
bc35512f | 1886 | } |
c263766c RH |
1887 | if (dump_file) |
1888 | fprintf (dump_file, "Deleted label in block %i.\n", | |
0b17ab2f | 1889 | b->index); |
e4ec2cac | 1890 | } |
402209ff | 1891 | |
e4ec2cac | 1892 | /* If we fall through an empty block, we can remove it. */ |
bc35512f JH |
1893 | if (!(mode & CLEANUP_CFGLAYOUT) |
1894 | && b->pred->pred_next == NULL | |
e4ec2cac | 1895 | && (b->pred->flags & EDGE_FALLTHRU) |
a813c111 | 1896 | && GET_CODE (BB_HEAD (b)) != CODE_LABEL |
e4ec2cac AO |
1897 | && FORWARDER_BLOCK_P (b) |
1898 | /* Note that forwarder_block_p true ensures that | |
1899 | there is a successor for this block. */ | |
1900 | && (b->succ->flags & EDGE_FALLTHRU) | |
0b17ab2f | 1901 | && n_basic_blocks > 1) |
e4ec2cac | 1902 | { |
c263766c RH |
1903 | if (dump_file) |
1904 | fprintf (dump_file, | |
e4ec2cac | 1905 | "Deleting fallthru block %i.\n", |
0b17ab2f | 1906 | b->index); |
e4ec2cac | 1907 | |
f6366fc7 | 1908 | c = b->prev_bb == ENTRY_BLOCK_PTR ? b->next_bb : b->prev_bb; |
e4ec2cac | 1909 | redirect_edge_succ_nodup (b->pred, b->succ->dest); |
f470c378 | 1910 | delete_basic_block (b); |
e4ec2cac AO |
1911 | changed = true; |
1912 | b = c; | |
1913 | } | |
5f0d2358 | 1914 | |
ec3ae3da JH |
1915 | if ((s = b->succ) != NULL |
1916 | && s->succ_next == NULL | |
1917 | && !(s->flags & EDGE_COMPLEX) | |
1918 | && (c = s->dest) != EXIT_BLOCK_PTR | |
1919 | && c->pred->pred_next == NULL | |
bc35512f JH |
1920 | && b != c) |
1921 | { | |
1922 | /* When not in cfg_layout mode use code aware of reordering | |
1923 | INSN. This code possibly creates new basic blocks so it | |
1924 | does not fit merge_blocks interface and is kept here in | |
1925 | hope that it will become useless once more of compiler | |
1926 | is transformed to use cfg_layout mode. */ | |
1927 | ||
1928 | if ((mode & CLEANUP_CFGLAYOUT) | |
1929 | && can_merge_blocks_p (b, c)) | |
1930 | { | |
1931 | merge_blocks (b, c); | |
1932 | update_forwarder_flag (b); | |
1933 | changed_here = true; | |
1934 | } | |
1935 | else if (!(mode & CLEANUP_CFGLAYOUT) | |
1936 | /* If the jump insn has side effects, | |
1937 | we can't kill the edge. */ | |
a813c111 | 1938 | && (GET_CODE (BB_END (b)) != JUMP_INSN |
e24e7211 | 1939 | || (reload_completed |
a813c111 SB |
1940 | ? simplejump_p (BB_END (b)) |
1941 | : onlyjump_p (BB_END (b)))) | |
bc35512f JH |
1942 | && (next = merge_blocks_move (s, b, c, mode))) |
1943 | { | |
1944 | b = next; | |
1945 | changed_here = true; | |
1946 | } | |
ec3ae3da | 1947 | } |
e4ec2cac AO |
1948 | |
1949 | /* Simplify branch over branch. */ | |
bc35512f JH |
1950 | if ((mode & CLEANUP_EXPENSIVE) |
1951 | && !(mode & CLEANUP_CFGLAYOUT) | |
1952 | && try_simplify_condjump (b)) | |
38c1593d | 1953 | changed_here = true; |
402209ff | 1954 | |
e4ec2cac AO |
1955 | /* If B has a single outgoing edge, but uses a |
1956 | non-trivial jump instruction without side-effects, we | |
1957 | can either delete the jump entirely, or replace it | |
3348b696 | 1958 | with a simple unconditional jump. */ |
e4ec2cac AO |
1959 | if (b->succ |
1960 | && ! b->succ->succ_next | |
1961 | && b->succ->dest != EXIT_BLOCK_PTR | |
a813c111 | 1962 | && onlyjump_p (BB_END (b)) |
750054a2 | 1963 | && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX) |
3348b696 | 1964 | && try_redirect_by_replacing_jump (b->succ, b->succ->dest, |
20b4e8ae | 1965 | (mode & CLEANUP_CFGLAYOUT) != 0)) |
e4ec2cac | 1966 | { |
e4ec2cac AO |
1967 | update_forwarder_flag (b); |
1968 | changed_here = true; | |
1969 | } | |
402209ff | 1970 | |
e4ec2cac AO |
1971 | /* Simplify branch to branch. */ |
1972 | if (try_forward_edges (mode, b)) | |
1973 | changed_here = true; | |
402209ff | 1974 | |
e4ec2cac AO |
1975 | /* Look for shared code between blocks. */ |
1976 | if ((mode & CLEANUP_CROSSJUMP) | |
1977 | && try_crossjump_bb (mode, b)) | |
1978 | changed_here = true; | |
402209ff | 1979 | |
e4ec2cac AO |
1980 | /* Don't get confused by the index shift caused by |
1981 | deleting blocks. */ | |
1982 | if (!changed_here) | |
e0082a72 | 1983 | b = b->next_bb; |
e4ec2cac AO |
1984 | else |
1985 | changed = true; | |
1986 | } | |
402209ff | 1987 | |
e4ec2cac AO |
1988 | if ((mode & CLEANUP_CROSSJUMP) |
1989 | && try_crossjump_bb (mode, EXIT_BLOCK_PTR)) | |
402209ff | 1990 | changed = true; |
402209ff JH |
1991 | |
1992 | #ifdef ENABLE_CHECKING | |
e4ec2cac AO |
1993 | if (changed) |
1994 | verify_flow_info (); | |
402209ff JH |
1995 | #endif |
1996 | ||
e4ec2cac | 1997 | changed_overall |= changed; |
7cf240d5 | 1998 | first_pass = false; |
e4ec2cac AO |
1999 | } |
2000 | while (changed); | |
402209ff | 2001 | } |
ca6c03ca JH |
2002 | |
2003 | if (mode & CLEANUP_CROSSJUMP) | |
2004 | remove_fake_edges (); | |
2005 | ||
1540f9eb | 2006 | clear_aux_for_blocks (); |
635559ab | 2007 | |
402209ff JH |
2008 | return changed_overall; |
2009 | } | |
2010 | \f | |
6d2f8887 | 2011 | /* Delete all unreachable basic blocks. */ |
4262e623 | 2012 | |
969d70ca | 2013 | bool |
d329e058 | 2014 | delete_unreachable_blocks (void) |
402209ff | 2015 | { |
402209ff | 2016 | bool changed = false; |
e0082a72 | 2017 | basic_block b, next_bb; |
402209ff JH |
2018 | |
2019 | find_unreachable_blocks (); | |
2020 | ||
bf77398c | 2021 | /* Delete all unreachable basic blocks. */ |
402209ff | 2022 | |
e0082a72 | 2023 | for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR; b = next_bb) |
402209ff | 2024 | { |
e0082a72 | 2025 | next_bb = b->next_bb; |
0b17ab2f | 2026 | |
402209ff | 2027 | if (!(b->flags & BB_REACHABLE)) |
6a58eee9 | 2028 | { |
f470c378 | 2029 | delete_basic_block (b); |
6a58eee9 RH |
2030 | changed = true; |
2031 | } | |
402209ff JH |
2032 | } |
2033 | ||
2034 | if (changed) | |
2035 | tidy_fallthru_edges (); | |
2036 | return changed; | |
2037 | } | |
6de9cd9a DN |
2038 | |
2039 | /* Merges sequential blocks if possible. */ | |
2040 | ||
2041 | bool | |
2042 | merge_seq_blocks (void) | |
2043 | { | |
2044 | basic_block bb; | |
2045 | bool changed = false; | |
2046 | ||
2047 | for (bb = ENTRY_BLOCK_PTR->next_bb; bb != EXIT_BLOCK_PTR; ) | |
2048 | { | |
2049 | if (bb->succ | |
2050 | && !bb->succ->succ_next | |
2051 | && can_merge_blocks_p (bb, bb->succ->dest)) | |
2052 | { | |
2053 | /* Merge the blocks and retry. */ | |
2054 | merge_blocks (bb, bb->succ->dest); | |
2055 | changed = true; | |
2056 | continue; | |
2057 | } | |
2058 | ||
2059 | bb = bb->next_bb; | |
2060 | } | |
2061 | ||
2062 | return changed; | |
2063 | } | |
402209ff JH |
2064 | \f |
2065 | /* Tidy the CFG by deleting unreachable code and whatnot. */ | |
2066 | ||
2067 | bool | |
d329e058 | 2068 | cleanup_cfg (int mode) |
402209ff | 2069 | { |
402209ff JH |
2070 | bool changed = false; |
2071 | ||
2072 | timevar_push (TV_CLEANUP_CFG); | |
3dec4024 JH |
2073 | if (delete_unreachable_blocks ()) |
2074 | { | |
2075 | changed = true; | |
2076 | /* We've possibly created trivially dead code. Cleanup it right | |
95bd1dd7 | 2077 | now to introduce more opportunities for try_optimize_cfg. */ |
95479831 DM |
2078 | if (!(mode & (CLEANUP_NO_INSN_DEL |
2079 | | CLEANUP_UPDATE_LIFE | CLEANUP_PRE_SIBCALL)) | |
3dec4024 JH |
2080 | && !reload_completed) |
2081 | delete_trivially_dead_insns (get_insns(), max_reg_num ()); | |
2082 | } | |
bf77398c ZD |
2083 | |
2084 | compact_blocks (); | |
2085 | ||
3dec4024 JH |
2086 | while (try_optimize_cfg (mode)) |
2087 | { | |
2088 | delete_unreachable_blocks (), changed = true; | |
2089 | if (mode & CLEANUP_UPDATE_LIFE) | |
2090 | { | |
95bd1dd7 KH |
2091 | /* Cleaning up CFG introduces more opportunities for dead code |
2092 | removal that in turn may introduce more opportunities for | |
3dec4024 | 2093 | cleaning up the CFG. */ |
e41f3392 | 2094 | if (!update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES, |
3dec4024 JH |
2095 | PROP_DEATH_NOTES |
2096 | | PROP_SCAN_DEAD_CODE | |
2097 | | PROP_KILL_DEAD_CODE | |
23bd7a93 JH |
2098 | | ((mode & CLEANUP_LOG_LINKS) |
2099 | ? PROP_LOG_LINKS : 0))) | |
3dec4024 JH |
2100 | break; |
2101 | } | |
95479831 | 2102 | else if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_PRE_SIBCALL)) |
1c4a429a | 2103 | && (mode & CLEANUP_EXPENSIVE) |
95479831 | 2104 | && !reload_completed) |
3dec4024 JH |
2105 | { |
2106 | if (!delete_trivially_dead_insns (get_insns(), max_reg_num ())) | |
2107 | break; | |
2108 | } | |
2109 | else | |
2110 | break; | |
2111 | delete_dead_jumptables (); | |
2112 | } | |
402209ff | 2113 | |
402209ff JH |
2114 | /* Kill the data we won't maintain. */ |
2115 | free_EXPR_LIST_list (&label_value_list); | |
402209ff JH |
2116 | timevar_pop (TV_CLEANUP_CFG); |
2117 | ||
402209ff JH |
2118 | return changed; |
2119 | } |