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402209ff JH |
1 | /* Control flow optimization code for GNU compiler. |
2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, | |
f773c2bd | 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010, 2011 |
62e5bf5d | 4 | Free Software Foundation, Inc. |
402209ff JH |
5 | |
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
402209ff JH |
11 | version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
402209ff | 21 | |
1ea7e6ad | 22 | /* This file contains optimizer of the control flow. The main entry point is |
402209ff JH |
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" | |
7932a3db | 40 | #include "regs.h" |
402209ff JH |
41 | #include "timevar.h" |
42 | #include "output.h" | |
43 | #include "insn-config.h" | |
44 | #include "flags.h" | |
45 | #include "recog.h" | |
718f9c0f | 46 | #include "diagnostic-core.h" |
8ecba28a | 47 | #include "cselib.h" |
5f24e0dc | 48 | #include "params.h" |
9f16e871 | 49 | #include "tm_p.h" |
e4ec2cac | 50 | #include "target.h" |
750054a2 | 51 | #include "cfglayout.h" |
78528714 | 52 | #include "emit-rtl.h" |
ef330312 PB |
53 | #include "tree-pass.h" |
54 | #include "cfgloop.h" | |
55 | #include "expr.h" | |
6fb5fa3c | 56 | #include "df.h" |
c1e3e2d9 | 57 | #include "dce.h" |
7d817ebc | 58 | #include "dbgcnt.h" |
402209ff | 59 | |
2dd2d53e | 60 | #define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK) |
c22cacf3 | 61 | |
7cf240d5 JH |
62 | /* Set to true when we are running first pass of try_optimize_cfg loop. */ |
63 | static bool first_pass; | |
c1e3e2d9 | 64 | |
073a8998 | 65 | /* Set to true if crossjumps occurred in the latest run of try_optimize_cfg. */ |
c1e3e2d9 SB |
66 | static bool crossjumps_occured; |
67 | ||
4ec5d4f5 BS |
68 | /* Set to true if we couldn't run an optimization due to stale liveness |
69 | information; we should run df_analyze to enable more opportunities. */ | |
70 | static bool block_was_dirty; | |
71 | ||
bf22920b | 72 | static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction); |
d329e058 | 73 | static bool try_crossjump_bb (int, basic_block); |
c2fc5456 | 74 | static bool outgoing_edges_match (int, basic_block, basic_block); |
472c95f5 | 75 | static enum replace_direction old_insns_match_p (int, rtx, rtx); |
d329e058 | 76 | |
d329e058 AJ |
77 | static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block); |
78 | static void merge_blocks_move_successor_nojumps (basic_block, basic_block); | |
d329e058 AJ |
79 | static bool try_optimize_cfg (int); |
80 | static bool try_simplify_condjump (basic_block); | |
81 | static bool try_forward_edges (int, basic_block); | |
6fb5fa3c | 82 | static edge thread_jump (edge, basic_block); |
d329e058 AJ |
83 | static bool mark_effect (rtx, bitmap); |
84 | static void notice_new_block (basic_block); | |
85 | static void update_forwarder_flag (basic_block); | |
86 | static int mentions_nonequal_regs (rtx *, void *); | |
c2fc5456 | 87 | static void merge_memattrs (rtx, rtx); |
635559ab JH |
88 | \f |
89 | /* Set flags for newly created block. */ | |
90 | ||
91 | static void | |
d329e058 | 92 | notice_new_block (basic_block bb) |
635559ab JH |
93 | { |
94 | if (!bb) | |
95 | return; | |
5f0d2358 | 96 | |
635559ab | 97 | if (forwarder_block_p (bb)) |
2dd2d53e | 98 | bb->flags |= BB_FORWARDER_BLOCK; |
635559ab JH |
99 | } |
100 | ||
101 | /* Recompute forwarder flag after block has been modified. */ | |
102 | ||
103 | static void | |
d329e058 | 104 | update_forwarder_flag (basic_block bb) |
635559ab JH |
105 | { |
106 | if (forwarder_block_p (bb)) | |
2dd2d53e | 107 | bb->flags |= BB_FORWARDER_BLOCK; |
635559ab | 108 | else |
2dd2d53e | 109 | bb->flags &= ~BB_FORWARDER_BLOCK; |
635559ab | 110 | } |
402209ff JH |
111 | \f |
112 | /* Simplify a conditional jump around an unconditional jump. | |
113 | Return true if something changed. */ | |
114 | ||
115 | static bool | |
d329e058 | 116 | try_simplify_condjump (basic_block cbranch_block) |
402209ff JH |
117 | { |
118 | basic_block jump_block, jump_dest_block, cbranch_dest_block; | |
119 | edge cbranch_jump_edge, cbranch_fallthru_edge; | |
120 | rtx cbranch_insn; | |
121 | ||
122 | /* Verify that there are exactly two successors. */ | |
628f6a4e | 123 | if (EDGE_COUNT (cbranch_block->succs) != 2) |
402209ff JH |
124 | return false; |
125 | ||
126 | /* Verify that we've got a normal conditional branch at the end | |
127 | of the block. */ | |
a813c111 | 128 | cbranch_insn = BB_END (cbranch_block); |
402209ff JH |
129 | if (!any_condjump_p (cbranch_insn)) |
130 | return false; | |
131 | ||
132 | cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block); | |
133 | cbranch_jump_edge = BRANCH_EDGE (cbranch_block); | |
134 | ||
135 | /* The next block must not have multiple predecessors, must not | |
136 | be the last block in the function, and must contain just the | |
137 | unconditional jump. */ | |
138 | jump_block = cbranch_fallthru_edge->dest; | |
c5cbcccf | 139 | if (!single_pred_p (jump_block) |
f6366fc7 | 140 | || jump_block->next_bb == EXIT_BLOCK_PTR |
635559ab | 141 | || !FORWARDER_BLOCK_P (jump_block)) |
402209ff | 142 | return false; |
c5cbcccf | 143 | jump_dest_block = single_succ (jump_block); |
402209ff | 144 | |
750054a2 CT |
145 | /* If we are partitioning hot/cold basic blocks, we don't want to |
146 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 | 147 | and cold sections. |
8e8d5162 CT |
148 | |
149 | Basic block partitioning may result in some jumps that appear to | |
c22cacf3 MS |
150 | be optimizable (or blocks that appear to be mergeable), but which really |
151 | must be left untouched (they are required to make it safely across | |
152 | partition boundaries). See the comments at the top of | |
8e8d5162 | 153 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
750054a2 | 154 | |
87c8b4be CT |
155 | if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block) |
156 | || (cbranch_jump_edge->flags & EDGE_CROSSING)) | |
750054a2 CT |
157 | return false; |
158 | ||
402209ff JH |
159 | /* The conditional branch must target the block after the |
160 | unconditional branch. */ | |
161 | cbranch_dest_block = cbranch_jump_edge->dest; | |
162 | ||
2f52c531 R |
163 | if (cbranch_dest_block == EXIT_BLOCK_PTR |
164 | || !can_fallthru (jump_block, cbranch_dest_block)) | |
402209ff JH |
165 | return false; |
166 | ||
ca6c03ca JH |
167 | /* Invert the conditional branch. */ |
168 | if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 0)) | |
169 | return false; | |
402209ff | 170 | |
c263766c RH |
171 | if (dump_file) |
172 | fprintf (dump_file, "Simplifying condjump %i around jump %i\n", | |
a813c111 | 173 | INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block))); |
402209ff JH |
174 | |
175 | /* Success. Update the CFG to match. Note that after this point | |
176 | the edge variable names appear backwards; the redirection is done | |
177 | this way to preserve edge profile data. */ | |
178 | cbranch_jump_edge = redirect_edge_succ_nodup (cbranch_jump_edge, | |
179 | cbranch_dest_block); | |
180 | cbranch_fallthru_edge = redirect_edge_succ_nodup (cbranch_fallthru_edge, | |
181 | jump_dest_block); | |
182 | cbranch_jump_edge->flags |= EDGE_FALLTHRU; | |
183 | cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU; | |
b446e5a2 | 184 | update_br_prob_note (cbranch_block); |
402209ff JH |
185 | |
186 | /* Delete the block with the unconditional jump, and clean up the mess. */ | |
f470c378 ZD |
187 | delete_basic_block (jump_block); |
188 | tidy_fallthru_edge (cbranch_jump_edge); | |
261139ce | 189 | update_forwarder_flag (cbranch_block); |
402209ff JH |
190 | |
191 | return true; | |
192 | } | |
193 | \f | |
8ecba28a JH |
194 | /* Attempt to prove that operation is NOOP using CSElib or mark the effect |
195 | on register. Used by jump threading. */ | |
5f0d2358 | 196 | |
8ecba28a | 197 | static bool |
d329e058 | 198 | mark_effect (rtx exp, regset nonequal) |
8ecba28a | 199 | { |
9f16e871 JH |
200 | int regno; |
201 | rtx dest; | |
8ecba28a JH |
202 | switch (GET_CODE (exp)) |
203 | { | |
204 | /* In case we do clobber the register, mark it as equal, as we know the | |
c22cacf3 | 205 | value is dead so it don't have to match. */ |
f87c27b4 KH |
206 | case CLOBBER: |
207 | if (REG_P (XEXP (exp, 0))) | |
208 | { | |
209 | dest = XEXP (exp, 0); | |
210 | regno = REGNO (dest); | |
f773c2bd AS |
211 | if (HARD_REGISTER_NUM_P (regno)) |
212 | bitmap_clear_range (nonequal, regno, | |
213 | hard_regno_nregs[regno][GET_MODE (dest)]); | |
214 | else | |
215 | bitmap_clear_bit (nonequal, regno); | |
f87c27b4 KH |
216 | } |
217 | return false; | |
5f0d2358 | 218 | |
f87c27b4 KH |
219 | case SET: |
220 | if (rtx_equal_for_cselib_p (SET_DEST (exp), SET_SRC (exp))) | |
8ecba28a | 221 | return false; |
f87c27b4 KH |
222 | dest = SET_DEST (exp); |
223 | if (dest == pc_rtx) | |
8ecba28a | 224 | return false; |
f87c27b4 KH |
225 | if (!REG_P (dest)) |
226 | return true; | |
227 | regno = REGNO (dest); | |
f773c2bd AS |
228 | if (HARD_REGISTER_NUM_P (regno)) |
229 | bitmap_set_range (nonequal, regno, | |
230 | hard_regno_nregs[regno][GET_MODE (dest)]); | |
231 | else | |
232 | bitmap_set_bit (nonequal, regno); | |
f87c27b4 KH |
233 | return false; |
234 | ||
235 | default: | |
236 | return false; | |
8ecba28a JH |
237 | } |
238 | } | |
fe477d8b | 239 | |
dcc24678 | 240 | /* Return nonzero if X is a register set in regset DATA. |
fe477d8b JH |
241 | Called via for_each_rtx. */ |
242 | static int | |
d329e058 | 243 | mentions_nonequal_regs (rtx *x, void *data) |
fe477d8b JH |
244 | { |
245 | regset nonequal = (regset) data; | |
246 | if (REG_P (*x)) | |
247 | { | |
248 | int regno; | |
249 | ||
250 | regno = REGNO (*x); | |
251 | if (REGNO_REG_SET_P (nonequal, regno)) | |
252 | return 1; | |
253 | if (regno < FIRST_PSEUDO_REGISTER) | |
254 | { | |
66fd46b6 | 255 | int n = hard_regno_nregs[regno][GET_MODE (*x)]; |
fe477d8b JH |
256 | while (--n > 0) |
257 | if (REGNO_REG_SET_P (nonequal, regno + n)) | |
258 | return 1; | |
259 | } | |
260 | } | |
261 | return 0; | |
262 | } | |
8ecba28a | 263 | /* Attempt to prove that the basic block B will have no side effects and |
95bd1dd7 | 264 | always continues in the same edge if reached via E. Return the edge |
8ecba28a JH |
265 | if exist, NULL otherwise. */ |
266 | ||
267 | static edge | |
6fb5fa3c | 268 | thread_jump (edge e, basic_block b) |
8ecba28a JH |
269 | { |
270 | rtx set1, set2, cond1, cond2, insn; | |
271 | enum rtx_code code1, code2, reversed_code2; | |
272 | bool reverse1 = false; | |
3cd8c58a | 273 | unsigned i; |
8ecba28a JH |
274 | regset nonequal; |
275 | bool failed = false; | |
a2041967 | 276 | reg_set_iterator rsi; |
8ecba28a | 277 | |
2dd2d53e | 278 | if (b->flags & BB_NONTHREADABLE_BLOCK) |
1540f9eb JH |
279 | return NULL; |
280 | ||
8ecba28a JH |
281 | /* At the moment, we do handle only conditional jumps, but later we may |
282 | want to extend this code to tablejumps and others. */ | |
628f6a4e | 283 | if (EDGE_COUNT (e->src->succs) != 2) |
8ecba28a | 284 | return NULL; |
628f6a4e | 285 | if (EDGE_COUNT (b->succs) != 2) |
1540f9eb | 286 | { |
2dd2d53e | 287 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
288 | return NULL; |
289 | } | |
8ecba28a JH |
290 | |
291 | /* Second branch must end with onlyjump, as we will eliminate the jump. */ | |
a813c111 | 292 | if (!any_condjump_p (BB_END (e->src))) |
8ecba28a | 293 | return NULL; |
f87c27b4 | 294 | |
a813c111 | 295 | if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b))) |
1540f9eb | 296 | { |
2dd2d53e | 297 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
298 | return NULL; |
299 | } | |
8ecba28a | 300 | |
a813c111 SB |
301 | set1 = pc_set (BB_END (e->src)); |
302 | set2 = pc_set (BB_END (b)); | |
8ecba28a | 303 | if (((e->flags & EDGE_FALLTHRU) != 0) |
68f3f6f1 | 304 | != (XEXP (SET_SRC (set1), 1) == pc_rtx)) |
8ecba28a JH |
305 | reverse1 = true; |
306 | ||
307 | cond1 = XEXP (SET_SRC (set1), 0); | |
308 | cond2 = XEXP (SET_SRC (set2), 0); | |
309 | if (reverse1) | |
a813c111 | 310 | code1 = reversed_comparison_code (cond1, BB_END (e->src)); |
8ecba28a JH |
311 | else |
312 | code1 = GET_CODE (cond1); | |
313 | ||
314 | code2 = GET_CODE (cond2); | |
a813c111 | 315 | reversed_code2 = reversed_comparison_code (cond2, BB_END (b)); |
8ecba28a JH |
316 | |
317 | if (!comparison_dominates_p (code1, code2) | |
318 | && !comparison_dominates_p (code1, reversed_code2)) | |
319 | return NULL; | |
320 | ||
321 | /* Ensure that the comparison operators are equivalent. | |
95bd1dd7 | 322 | ??? This is far too pessimistic. We should allow swapped operands, |
8ecba28a JH |
323 | different CCmodes, or for example comparisons for interval, that |
324 | dominate even when operands are not equivalent. */ | |
325 | if (!rtx_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
326 | || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
327 | return NULL; | |
328 | ||
329 | /* Short circuit cases where block B contains some side effects, as we can't | |
330 | safely bypass it. */ | |
a813c111 | 331 | for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)); |
8ecba28a JH |
332 | insn = NEXT_INSN (insn)) |
333 | if (INSN_P (insn) && side_effects_p (PATTERN (insn))) | |
1540f9eb | 334 | { |
2dd2d53e | 335 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
336 | return NULL; |
337 | } | |
8ecba28a | 338 | |
457eeaae | 339 | cselib_init (0); |
8ecba28a JH |
340 | |
341 | /* First process all values computed in the source basic block. */ | |
3cd8c58a NS |
342 | for (insn = NEXT_INSN (BB_HEAD (e->src)); |
343 | insn != NEXT_INSN (BB_END (e->src)); | |
8ecba28a JH |
344 | insn = NEXT_INSN (insn)) |
345 | if (INSN_P (insn)) | |
346 | cselib_process_insn (insn); | |
347 | ||
8bdbfff5 | 348 | nonequal = BITMAP_ALLOC (NULL); |
8ecba28a | 349 | CLEAR_REG_SET (nonequal); |
5f0d2358 | 350 | |
8ecba28a JH |
351 | /* Now assume that we've continued by the edge E to B and continue |
352 | processing as if it were same basic block. | |
8ecba28a | 353 | Our goal is to prove that whole block is an NOOP. */ |
5f0d2358 | 354 | |
3cd8c58a NS |
355 | for (insn = NEXT_INSN (BB_HEAD (b)); |
356 | insn != NEXT_INSN (BB_END (b)) && !failed; | |
8ecba28a | 357 | insn = NEXT_INSN (insn)) |
f87c27b4 KH |
358 | { |
359 | if (INSN_P (insn)) | |
360 | { | |
361 | rtx pat = PATTERN (insn); | |
362 | ||
363 | if (GET_CODE (pat) == PARALLEL) | |
364 | { | |
3cd8c58a | 365 | for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++) |
f87c27b4 KH |
366 | failed |= mark_effect (XVECEXP (pat, 0, i), nonequal); |
367 | } | |
368 | else | |
369 | failed |= mark_effect (pat, nonequal); | |
370 | } | |
5f0d2358 | 371 | |
f87c27b4 KH |
372 | cselib_process_insn (insn); |
373 | } | |
8ecba28a JH |
374 | |
375 | /* Later we should clear nonequal of dead registers. So far we don't | |
376 | have life information in cfg_cleanup. */ | |
377 | if (failed) | |
1540f9eb | 378 | { |
2dd2d53e | 379 | b->flags |= BB_NONTHREADABLE_BLOCK; |
1540f9eb JH |
380 | goto failed_exit; |
381 | } | |
8ecba28a | 382 | |
fe477d8b JH |
383 | /* cond2 must not mention any register that is not equal to the |
384 | former block. */ | |
385 | if (for_each_rtx (&cond2, mentions_nonequal_regs, nonequal)) | |
386 | goto failed_exit; | |
387 | ||
a2041967 KH |
388 | EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi) |
389 | goto failed_exit; | |
8ecba28a | 390 | |
8bdbfff5 | 391 | BITMAP_FREE (nonequal); |
8ecba28a JH |
392 | cselib_finish (); |
393 | if ((comparison_dominates_p (code1, code2) != 0) | |
4deaa2f8 | 394 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) |
8ecba28a JH |
395 | return BRANCH_EDGE (b); |
396 | else | |
397 | return FALLTHRU_EDGE (b); | |
398 | ||
399 | failed_exit: | |
8bdbfff5 | 400 | BITMAP_FREE (nonequal); |
8ecba28a JH |
401 | cselib_finish (); |
402 | return NULL; | |
403 | } | |
404 | \f | |
402209ff | 405 | /* Attempt to forward edges leaving basic block B. |
eaec9b3d | 406 | Return true if successful. */ |
402209ff JH |
407 | |
408 | static bool | |
d329e058 | 409 | try_forward_edges (int mode, basic_block b) |
402209ff JH |
410 | { |
411 | bool changed = false; | |
628f6a4e BE |
412 | edge_iterator ei; |
413 | edge e, *threaded_edges = NULL; | |
402209ff | 414 | |
750054a2 CT |
415 | /* If we are partitioning hot/cold basic blocks, we don't want to |
416 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
417 | and cold sections. |
418 | ||
8e8d5162 | 419 | Basic block partitioning may result in some jumps that appear to |
fa10beec RW |
420 | be optimizable (or blocks that appear to be mergeable), but which really |
421 | must be left untouched (they are required to make it safely across | |
c22cacf3 | 422 | partition boundaries). See the comments at the top of |
8e8d5162 CT |
423 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
424 | ||
87c8b4be | 425 | if (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)) |
750054a2 CT |
426 | return false; |
427 | ||
628f6a4e | 428 | for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); ) |
402209ff JH |
429 | { |
430 | basic_block target, first; | |
7241571e | 431 | int counter, goto_locus; |
8ecba28a | 432 | bool threaded = false; |
bcb3bc6d | 433 | int nthreaded_edges = 0; |
4ec5d4f5 | 434 | bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0; |
402209ff | 435 | |
402209ff JH |
436 | /* Skip complex edges because we don't know how to update them. |
437 | ||
c22cacf3 MS |
438 | Still handle fallthru edges, as we can succeed to forward fallthru |
439 | edge to the same place as the branch edge of conditional branch | |
440 | and turn conditional branch to an unconditional branch. */ | |
402209ff | 441 | if (e->flags & EDGE_COMPLEX) |
628f6a4e BE |
442 | { |
443 | ei_next (&ei); | |
444 | continue; | |
445 | } | |
402209ff JH |
446 | |
447 | target = first = e->dest; | |
24bd1a0b | 448 | counter = NUM_FIXED_BLOCKS; |
7241571e | 449 | goto_locus = e->goto_locus; |
402209ff | 450 | |
9fb32434 | 451 | /* If we are partitioning hot/cold basic_blocks, we don't want to mess |
8e8d5162 CT |
452 | up jumps that cross between hot/cold sections. |
453 | ||
454 | Basic block partitioning may result in some jumps that appear | |
c22cacf3 MS |
455 | to be optimizable (or blocks that appear to be mergeable), but which |
456 | really must be left untouched (they are required to make it safely | |
8e8d5162 CT |
457 | across partition boundaries). See the comments at the top of |
458 | bb-reorder.c:partition_hot_cold_basic_blocks for complete | |
459 | details. */ | |
9fb32434 | 460 | |
87c8b4be | 461 | if (first != EXIT_BLOCK_PTR |
9fb32434 CT |
462 | && find_reg_note (BB_END (first), REG_CROSSING_JUMP, NULL_RTX)) |
463 | return false; | |
464 | ||
0b17ab2f | 465 | while (counter < n_basic_blocks) |
402209ff | 466 | { |
8ecba28a JH |
467 | basic_block new_target = NULL; |
468 | bool new_target_threaded = false; | |
4ec5d4f5 | 469 | may_thread |= (target->flags & BB_MODIFIED) != 0; |
8ecba28a JH |
470 | |
471 | if (FORWARDER_BLOCK_P (target) | |
c22cacf3 | 472 | && !(single_succ_edge (target)->flags & EDGE_CROSSING) |
c5cbcccf | 473 | && single_succ (target) != EXIT_BLOCK_PTR) |
8ecba28a JH |
474 | { |
475 | /* Bypass trivial infinite loops. */ | |
c5cbcccf ZD |
476 | new_target = single_succ (target); |
477 | if (target == new_target) | |
0b17ab2f | 478 | counter = n_basic_blocks; |
7241571e JJ |
479 | else if (!optimize) |
480 | { | |
481 | /* When not optimizing, ensure that edges or forwarder | |
482 | blocks with different locus are not optimized out. */ | |
50a36e42 EB |
483 | int new_locus = single_succ_edge (target)->goto_locus; |
484 | int locus = goto_locus; | |
7241571e | 485 | |
50a36e42 EB |
486 | if (new_locus && locus && !locator_eq (new_locus, locus)) |
487 | new_target = NULL; | |
488 | else | |
7241571e | 489 | { |
11321111 AO |
490 | rtx last; |
491 | ||
50a36e42 EB |
492 | if (new_locus) |
493 | locus = new_locus; | |
7241571e | 494 | |
11321111 AO |
495 | last = BB_END (target); |
496 | if (DEBUG_INSN_P (last)) | |
497 | last = prev_nondebug_insn (last); | |
498 | ||
499 | new_locus = last && INSN_P (last) | |
500 | ? INSN_LOCATOR (last) : 0; | |
50a36e42 EB |
501 | |
502 | if (new_locus && locus && !locator_eq (new_locus, locus)) | |
503 | new_target = NULL; | |
504 | else | |
505 | { | |
506 | if (new_locus) | |
507 | locus = new_locus; | |
508 | ||
509 | goto_locus = locus; | |
510 | } | |
7241571e JJ |
511 | } |
512 | } | |
8ecba28a | 513 | } |
5f0d2358 | 514 | |
8ecba28a JH |
515 | /* Allow to thread only over one edge at time to simplify updating |
516 | of probabilities. */ | |
7cf240d5 | 517 | else if ((mode & CLEANUP_THREADING) && may_thread) |
8ecba28a | 518 | { |
6fb5fa3c | 519 | edge t = thread_jump (e, target); |
1c570418 | 520 | if (t) |
8ecba28a | 521 | { |
bcb3bc6d | 522 | if (!threaded_edges) |
5ed6ace5 | 523 | threaded_edges = XNEWVEC (edge, n_basic_blocks); |
3b3b1e32 RH |
524 | else |
525 | { | |
526 | int i; | |
527 | ||
528 | /* Detect an infinite loop across blocks not | |
529 | including the start block. */ | |
530 | for (i = 0; i < nthreaded_edges; ++i) | |
531 | if (threaded_edges[i] == t) | |
532 | break; | |
533 | if (i < nthreaded_edges) | |
b90e45ae | 534 | { |
0b17ab2f | 535 | counter = n_basic_blocks; |
b90e45ae JH |
536 | break; |
537 | } | |
3b3b1e32 RH |
538 | } |
539 | ||
540 | /* Detect an infinite loop across the start block. */ | |
541 | if (t->dest == b) | |
542 | break; | |
543 | ||
24bd1a0b | 544 | gcc_assert (nthreaded_edges < n_basic_blocks - NUM_FIXED_BLOCKS); |
1c570418 | 545 | threaded_edges[nthreaded_edges++] = t; |
3b3b1e32 RH |
546 | |
547 | new_target = t->dest; | |
548 | new_target_threaded = true; | |
8ecba28a JH |
549 | } |
550 | } | |
5f0d2358 | 551 | |
8ecba28a JH |
552 | if (!new_target) |
553 | break; | |
402209ff | 554 | |
8ecba28a JH |
555 | counter++; |
556 | target = new_target; | |
557 | threaded |= new_target_threaded; | |
f87c27b4 | 558 | } |
402209ff | 559 | |
0b17ab2f | 560 | if (counter >= n_basic_blocks) |
402209ff | 561 | { |
c263766c RH |
562 | if (dump_file) |
563 | fprintf (dump_file, "Infinite loop in BB %i.\n", | |
0b17ab2f | 564 | target->index); |
402209ff JH |
565 | } |
566 | else if (target == first) | |
567 | ; /* We didn't do anything. */ | |
568 | else | |
569 | { | |
570 | /* Save the values now, as the edge may get removed. */ | |
571 | gcov_type edge_count = e->count; | |
572 | int edge_probability = e->probability; | |
8ecba28a | 573 | int edge_frequency; |
1c570418 | 574 | int n = 0; |
402209ff | 575 | |
7241571e JJ |
576 | e->goto_locus = goto_locus; |
577 | ||
6ee3c8e4 JJ |
578 | /* Don't force if target is exit block. */ |
579 | if (threaded && target != EXIT_BLOCK_PTR) | |
402209ff | 580 | { |
8ecba28a | 581 | notice_new_block (redirect_edge_and_branch_force (e, target)); |
c263766c RH |
582 | if (dump_file) |
583 | fprintf (dump_file, "Conditionals threaded.\n"); | |
402209ff | 584 | } |
8ecba28a | 585 | else if (!redirect_edge_and_branch (e, target)) |
402209ff | 586 | { |
c263766c RH |
587 | if (dump_file) |
588 | fprintf (dump_file, | |
5f0d2358 | 589 | "Forwarding edge %i->%i to %i failed.\n", |
0b17ab2f | 590 | b->index, e->dest->index, target->index); |
628f6a4e | 591 | ei_next (&ei); |
8ecba28a | 592 | continue; |
402209ff | 593 | } |
5f0d2358 | 594 | |
8ecba28a JH |
595 | /* We successfully forwarded the edge. Now update profile |
596 | data: for each edge we traversed in the chain, remove | |
597 | the original edge's execution count. */ | |
598 | edge_frequency = ((edge_probability * b->frequency | |
599 | + REG_BR_PROB_BASE / 2) | |
600 | / REG_BR_PROB_BASE); | |
601 | ||
8ecba28a JH |
602 | do |
603 | { | |
604 | edge t; | |
5f0d2358 | 605 | |
c5cbcccf | 606 | if (!single_succ_p (first)) |
3b3b1e32 | 607 | { |
341c100f | 608 | gcc_assert (n < nthreaded_edges); |
3b3b1e32 | 609 | t = threaded_edges [n++]; |
341c100f | 610 | gcc_assert (t->src == first); |
15db5571 JH |
611 | update_bb_profile_for_threading (first, edge_frequency, |
612 | edge_count, t); | |
b446e5a2 | 613 | update_br_prob_note (first); |
3b3b1e32 | 614 | } |
8ecba28a | 615 | else |
bcb3bc6d | 616 | { |
15db5571 JH |
617 | first->count -= edge_count; |
618 | if (first->count < 0) | |
619 | first->count = 0; | |
620 | first->frequency -= edge_frequency; | |
621 | if (first->frequency < 0) | |
622 | first->frequency = 0; | |
bcb3bc6d JH |
623 | /* It is possible that as the result of |
624 | threading we've removed edge as it is | |
625 | threaded to the fallthru edge. Avoid | |
626 | getting out of sync. */ | |
627 | if (n < nthreaded_edges | |
628 | && first == threaded_edges [n]->src) | |
629 | n++; | |
c5cbcccf | 630 | t = single_succ_edge (first); |
f87c27b4 | 631 | } |
5f0d2358 | 632 | |
b446e5a2 JH |
633 | t->count -= edge_count; |
634 | if (t->count < 0) | |
635 | t->count = 0; | |
8ecba28a JH |
636 | first = t->dest; |
637 | } | |
638 | while (first != target); | |
639 | ||
640 | changed = true; | |
628f6a4e | 641 | continue; |
402209ff | 642 | } |
628f6a4e | 643 | ei_next (&ei); |
402209ff JH |
644 | } |
645 | ||
04695783 | 646 | free (threaded_edges); |
402209ff JH |
647 | return changed; |
648 | } | |
649 | \f | |
402209ff JH |
650 | |
651 | /* Blocks A and B are to be merged into a single block. A has no incoming | |
652 | fallthru edge, so it can be moved before B without adding or modifying | |
653 | any jumps (aside from the jump from A to B). */ | |
654 | ||
4262e623 | 655 | static void |
d329e058 | 656 | merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b) |
402209ff JH |
657 | { |
658 | rtx barrier; | |
402209ff | 659 | |
750054a2 CT |
660 | /* If we are partitioning hot/cold basic blocks, we don't want to |
661 | mess up unconditional or indirect jumps that cross between hot | |
8e8d5162 | 662 | and cold sections. |
c22cacf3 | 663 | |
8e8d5162 | 664 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
665 | be optimizable (or blocks that appear to be mergeable), but which really |
666 | must be left untouched (they are required to make it safely across | |
667 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
668 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
669 | ||
87c8b4be | 670 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
750054a2 CT |
671 | return; |
672 | ||
a813c111 | 673 | barrier = next_nonnote_insn (BB_END (a)); |
341c100f | 674 | gcc_assert (BARRIER_P (barrier)); |
53c17031 | 675 | delete_insn (barrier); |
402209ff | 676 | |
402209ff | 677 | /* Scramble the insn chain. */ |
a813c111 SB |
678 | if (BB_END (a) != PREV_INSN (BB_HEAD (b))) |
679 | reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b))); | |
6fb5fa3c | 680 | df_set_bb_dirty (a); |
402209ff | 681 | |
c263766c RH |
682 | if (dump_file) |
683 | fprintf (dump_file, "Moved block %d before %d and merged.\n", | |
0b17ab2f | 684 | a->index, b->index); |
402209ff | 685 | |
bf77398c | 686 | /* Swap the records for the two blocks around. */ |
402209ff | 687 | |
918ed612 ZD |
688 | unlink_block (a); |
689 | link_block (a, b->prev_bb); | |
690 | ||
402209ff | 691 | /* Now blocks A and B are contiguous. Merge them. */ |
bc35512f | 692 | merge_blocks (a, b); |
402209ff JH |
693 | } |
694 | ||
695 | /* Blocks A and B are to be merged into a single block. B has no outgoing | |
696 | fallthru edge, so it can be moved after A without adding or modifying | |
697 | any jumps (aside from the jump from A to B). */ | |
698 | ||
4262e623 | 699 | static void |
d329e058 | 700 | merge_blocks_move_successor_nojumps (basic_block a, basic_block b) |
402209ff | 701 | { |
f62ce55b | 702 | rtx barrier, real_b_end; |
ee735eef | 703 | rtx label, table; |
402209ff | 704 | |
750054a2 CT |
705 | /* If we are partitioning hot/cold basic blocks, we don't want to |
706 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
707 | and cold sections. |
708 | ||
8e8d5162 | 709 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
710 | be optimizable (or blocks that appear to be mergeable), but which really |
711 | must be left untouched (they are required to make it safely across | |
712 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
713 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
714 | ||
87c8b4be | 715 | if (BB_PARTITION (a) != BB_PARTITION (b)) |
750054a2 CT |
716 | return; |
717 | ||
a813c111 | 718 | real_b_end = BB_END (b); |
402209ff | 719 | |
ee735eef JZ |
720 | /* If there is a jump table following block B temporarily add the jump table |
721 | to block B so that it will also be moved to the correct location. */ | |
a813c111 SB |
722 | if (tablejump_p (BB_END (b), &label, &table) |
723 | && prev_active_insn (label) == BB_END (b)) | |
402209ff | 724 | { |
a813c111 | 725 | BB_END (b) = table; |
402209ff JH |
726 | } |
727 | ||
728 | /* There had better have been a barrier there. Delete it. */ | |
a813c111 | 729 | barrier = NEXT_INSN (BB_END (b)); |
4b4bf941 | 730 | if (barrier && BARRIER_P (barrier)) |
53c17031 | 731 | delete_insn (barrier); |
402209ff | 732 | |
402209ff JH |
733 | |
734 | /* Scramble the insn chain. */ | |
a813c111 | 735 | reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a)); |
402209ff | 736 | |
f62ce55b | 737 | /* Restore the real end of b. */ |
a813c111 | 738 | BB_END (b) = real_b_end; |
f62ce55b | 739 | |
c263766c RH |
740 | if (dump_file) |
741 | fprintf (dump_file, "Moved block %d after %d and merged.\n", | |
0b17ab2f | 742 | b->index, a->index); |
2150ad33 RH |
743 | |
744 | /* Now blocks A and B are contiguous. Merge them. */ | |
bc35512f | 745 | merge_blocks (a, b); |
402209ff JH |
746 | } |
747 | ||
748 | /* Attempt to merge basic blocks that are potentially non-adjacent. | |
ec3ae3da JH |
749 | Return NULL iff the attempt failed, otherwise return basic block |
750 | where cleanup_cfg should continue. Because the merging commonly | |
751 | moves basic block away or introduces another optimization | |
e0bb17a8 | 752 | possibility, return basic block just before B so cleanup_cfg don't |
ec3ae3da JH |
753 | need to iterate. |
754 | ||
755 | It may be good idea to return basic block before C in the case | |
756 | C has been moved after B and originally appeared earlier in the | |
4d6922ee | 757 | insn sequence, but we have no information available about the |
ec3ae3da JH |
758 | relative ordering of these two. Hopefully it is not too common. */ |
759 | ||
760 | static basic_block | |
bc35512f | 761 | merge_blocks_move (edge e, basic_block b, basic_block c, int mode) |
402209ff | 762 | { |
ec3ae3da | 763 | basic_block next; |
402209ff | 764 | |
750054a2 CT |
765 | /* If we are partitioning hot/cold basic blocks, we don't want to |
766 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
767 | and cold sections. |
768 | ||
8e8d5162 | 769 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
770 | be optimizable (or blocks that appear to be mergeable), but which really |
771 | must be left untouched (they are required to make it safely across | |
772 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
773 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
774 | ||
87c8b4be | 775 | if (BB_PARTITION (b) != BB_PARTITION (c)) |
750054a2 | 776 | return NULL; |
c22cacf3 | 777 | |
402209ff JH |
778 | /* If B has a fallthru edge to C, no need to move anything. */ |
779 | if (e->flags & EDGE_FALLTHRU) | |
780 | { | |
0b17ab2f | 781 | int b_index = b->index, c_index = c->index; |
7d776ee2 RG |
782 | |
783 | /* Protect the loop latches. */ | |
784 | if (current_loops && c->loop_father->latch == c) | |
785 | return NULL; | |
786 | ||
bc35512f | 787 | merge_blocks (b, c); |
635559ab | 788 | update_forwarder_flag (b); |
402209ff | 789 | |
c263766c RH |
790 | if (dump_file) |
791 | fprintf (dump_file, "Merged %d and %d without moving.\n", | |
f87c27b4 | 792 | b_index, c_index); |
402209ff | 793 | |
ec3ae3da | 794 | return b->prev_bb == ENTRY_BLOCK_PTR ? b : b->prev_bb; |
402209ff | 795 | } |
5f0d2358 | 796 | |
402209ff JH |
797 | /* Otherwise we will need to move code around. Do that only if expensive |
798 | transformations are allowed. */ | |
799 | else if (mode & CLEANUP_EXPENSIVE) | |
800 | { | |
4262e623 JH |
801 | edge tmp_edge, b_fallthru_edge; |
802 | bool c_has_outgoing_fallthru; | |
803 | bool b_has_incoming_fallthru; | |
402209ff JH |
804 | |
805 | /* Avoid overactive code motion, as the forwarder blocks should be | |
c22cacf3 | 806 | eliminated by edge redirection instead. One exception might have |
402209ff JH |
807 | been if B is a forwarder block and C has no fallthru edge, but |
808 | that should be cleaned up by bb-reorder instead. */ | |
635559ab | 809 | if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c)) |
ec3ae3da | 810 | return NULL; |
402209ff JH |
811 | |
812 | /* We must make sure to not munge nesting of lexical blocks, | |
813 | and loop notes. This is done by squeezing out all the notes | |
814 | and leaving them there to lie. Not ideal, but functional. */ | |
815 | ||
0fd4b31d | 816 | tmp_edge = find_fallthru_edge (c->succs); |
402209ff | 817 | c_has_outgoing_fallthru = (tmp_edge != NULL); |
402209ff | 818 | |
0fd4b31d | 819 | tmp_edge = find_fallthru_edge (b->preds); |
402209ff | 820 | b_has_incoming_fallthru = (tmp_edge != NULL); |
4262e623 | 821 | b_fallthru_edge = tmp_edge; |
ec3ae3da | 822 | next = b->prev_bb; |
912b79e7 JH |
823 | if (next == c) |
824 | next = next->prev_bb; | |
4262e623 JH |
825 | |
826 | /* Otherwise, we're going to try to move C after B. If C does | |
827 | not have an outgoing fallthru, then it can be moved | |
828 | immediately after B without introducing or modifying jumps. */ | |
829 | if (! c_has_outgoing_fallthru) | |
830 | { | |
831 | merge_blocks_move_successor_nojumps (b, c); | |
c22cacf3 | 832 | return next == ENTRY_BLOCK_PTR ? next->next_bb : next; |
4262e623 | 833 | } |
402209ff JH |
834 | |
835 | /* If B does not have an incoming fallthru, then it can be moved | |
836 | immediately before C without introducing or modifying jumps. | |
837 | C cannot be the first block, so we do not have to worry about | |
838 | accessing a non-existent block. */ | |
402209ff | 839 | |
4262e623 JH |
840 | if (b_has_incoming_fallthru) |
841 | { | |
473fb060 | 842 | basic_block bb; |
5f0d2358 | 843 | |
4262e623 | 844 | if (b_fallthru_edge->src == ENTRY_BLOCK_PTR) |
ec3ae3da | 845 | return NULL; |
7dddfb65 JH |
846 | bb = force_nonfallthru (b_fallthru_edge); |
847 | if (bb) | |
848 | notice_new_block (bb); | |
4262e623 | 849 | } |
5f0d2358 | 850 | |
4262e623 | 851 | merge_blocks_move_predecessor_nojumps (b, c); |
ec3ae3da | 852 | return next == ENTRY_BLOCK_PTR ? next->next_bb : next; |
402209ff | 853 | } |
5f0d2358 | 854 | |
10d6c0d0 | 855 | return NULL; |
402209ff JH |
856 | } |
857 | \f | |
c2fc5456 R |
858 | |
859 | /* Removes the memory attributes of MEM expression | |
860 | if they are not equal. */ | |
861 | ||
862 | void | |
863 | merge_memattrs (rtx x, rtx y) | |
864 | { | |
865 | int i; | |
866 | int j; | |
867 | enum rtx_code code; | |
868 | const char *fmt; | |
869 | ||
870 | if (x == y) | |
871 | return; | |
872 | if (x == 0 || y == 0) | |
873 | return; | |
874 | ||
875 | code = GET_CODE (x); | |
876 | ||
877 | if (code != GET_CODE (y)) | |
878 | return; | |
879 | ||
880 | if (GET_MODE (x) != GET_MODE (y)) | |
881 | return; | |
882 | ||
883 | if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y)) | |
884 | { | |
885 | if (! MEM_ATTRS (x)) | |
886 | MEM_ATTRS (y) = 0; | |
887 | else if (! MEM_ATTRS (y)) | |
888 | MEM_ATTRS (x) = 0; | |
c22cacf3 | 889 | else |
c2fc5456 | 890 | { |
f5541398 | 891 | HOST_WIDE_INT mem_size; |
c2fc5456 R |
892 | |
893 | if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) | |
894 | { | |
895 | set_mem_alias_set (x, 0); | |
896 | set_mem_alias_set (y, 0); | |
897 | } | |
c22cacf3 | 898 | |
c2fc5456 R |
899 | if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y))) |
900 | { | |
901 | set_mem_expr (x, 0); | |
902 | set_mem_expr (y, 0); | |
527210c4 RS |
903 | clear_mem_offset (x); |
904 | clear_mem_offset (y); | |
c2fc5456 | 905 | } |
527210c4 RS |
906 | else if (MEM_OFFSET_KNOWN_P (x) != MEM_OFFSET_KNOWN_P (y) |
907 | || (MEM_OFFSET_KNOWN_P (x) | |
908 | && MEM_OFFSET (x) != MEM_OFFSET (y))) | |
c2fc5456 | 909 | { |
527210c4 RS |
910 | clear_mem_offset (x); |
911 | clear_mem_offset (y); | |
c2fc5456 | 912 | } |
c22cacf3 | 913 | |
f5541398 RS |
914 | if (MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y)) |
915 | { | |
916 | mem_size = MAX (MEM_SIZE (x), MEM_SIZE (y)); | |
917 | set_mem_size (x, mem_size); | |
918 | set_mem_size (y, mem_size); | |
919 | } | |
c2fc5456 | 920 | else |
f5541398 RS |
921 | { |
922 | clear_mem_size (x); | |
923 | clear_mem_size (y); | |
924 | } | |
c2fc5456 R |
925 | |
926 | set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y))); | |
927 | set_mem_align (y, MEM_ALIGN (x)); | |
928 | } | |
929 | } | |
c22cacf3 | 930 | |
c2fc5456 R |
931 | fmt = GET_RTX_FORMAT (code); |
932 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
933 | { | |
934 | switch (fmt[i]) | |
935 | { | |
936 | case 'E': | |
937 | /* Two vectors must have the same length. */ | |
938 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
939 | return; | |
940 | ||
941 | for (j = 0; j < XVECLEN (x, i); j++) | |
942 | merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j)); | |
943 | ||
944 | break; | |
945 | ||
946 | case 'e': | |
947 | merge_memattrs (XEXP (x, i), XEXP (y, i)); | |
948 | } | |
949 | } | |
950 | return; | |
951 | } | |
952 | ||
953 | ||
472c95f5 TV |
954 | /* Checks if patterns P1 and P2 are equivalent, apart from the possibly |
955 | different single sets S1 and S2. */ | |
c2fc5456 R |
956 | |
957 | static bool | |
472c95f5 TV |
958 | equal_different_set_p (rtx p1, rtx s1, rtx p2, rtx s2) |
959 | { | |
960 | int i; | |
961 | rtx e1, e2; | |
962 | ||
963 | if (p1 == s1 && p2 == s2) | |
964 | return true; | |
965 | ||
966 | if (GET_CODE (p1) != PARALLEL || GET_CODE (p2) != PARALLEL) | |
967 | return false; | |
968 | ||
969 | if (XVECLEN (p1, 0) != XVECLEN (p2, 0)) | |
970 | return false; | |
971 | ||
972 | for (i = 0; i < XVECLEN (p1, 0); i++) | |
973 | { | |
974 | e1 = XVECEXP (p1, 0, i); | |
975 | e2 = XVECEXP (p2, 0, i); | |
976 | if (e1 == s1 && e2 == s2) | |
977 | continue; | |
978 | if (reload_completed | |
979 | ? rtx_renumbered_equal_p (e1, e2) : rtx_equal_p (e1, e2)) | |
980 | continue; | |
981 | ||
982 | return false; | |
983 | } | |
984 | ||
985 | return true; | |
986 | } | |
987 | ||
988 | /* Examine register notes on I1 and I2 and return: | |
989 | - dir_forward if I1 can be replaced by I2, or | |
990 | - dir_backward if I2 can be replaced by I1, or | |
991 | - dir_both if both are the case. */ | |
992 | ||
993 | static enum replace_direction | |
994 | can_replace_by (rtx i1, rtx i2) | |
995 | { | |
996 | rtx s1, s2, d1, d2, src1, src2, note1, note2; | |
997 | bool c1, c2; | |
998 | ||
999 | /* Check for 2 sets. */ | |
1000 | s1 = single_set (i1); | |
1001 | s2 = single_set (i2); | |
1002 | if (s1 == NULL_RTX || s2 == NULL_RTX) | |
1003 | return dir_none; | |
1004 | ||
1005 | /* Check that the 2 sets set the same dest. */ | |
1006 | d1 = SET_DEST (s1); | |
1007 | d2 = SET_DEST (s2); | |
1008 | if (!(reload_completed | |
1009 | ? rtx_renumbered_equal_p (d1, d2) : rtx_equal_p (d1, d2))) | |
1010 | return dir_none; | |
1011 | ||
1012 | /* Find identical req_equiv or reg_equal note, which implies that the 2 sets | |
1013 | set dest to the same value. */ | |
1014 | note1 = find_reg_equal_equiv_note (i1); | |
1015 | note2 = find_reg_equal_equiv_note (i2); | |
1016 | if (!note1 || !note2 || !rtx_equal_p (XEXP (note1, 0), XEXP (note2, 0)) | |
1017 | || !CONST_INT_P (XEXP (note1, 0))) | |
1018 | return dir_none; | |
1019 | ||
1020 | if (!equal_different_set_p (PATTERN (i1), s1, PATTERN (i2), s2)) | |
1021 | return dir_none; | |
1022 | ||
1023 | /* Although the 2 sets set dest to the same value, we cannot replace | |
1024 | (set (dest) (const_int)) | |
1025 | by | |
1026 | (set (dest) (reg)) | |
1027 | because we don't know if the reg is live and has the same value at the | |
1028 | location of replacement. */ | |
1029 | src1 = SET_SRC (s1); | |
1030 | src2 = SET_SRC (s2); | |
1031 | c1 = CONST_INT_P (src1); | |
1032 | c2 = CONST_INT_P (src2); | |
1033 | if (c1 && c2) | |
1034 | return dir_both; | |
1035 | else if (c2) | |
1036 | return dir_forward; | |
1037 | else if (c1) | |
1038 | return dir_backward; | |
1039 | ||
1040 | return dir_none; | |
1041 | } | |
1042 | ||
1043 | /* Merges directions A and B. */ | |
1044 | ||
1045 | static enum replace_direction | |
1046 | merge_dir (enum replace_direction a, enum replace_direction b) | |
1047 | { | |
1048 | /* Implements the following table: | |
1049 | |bo fw bw no | |
1050 | ---+----------- | |
1051 | bo |bo fw bw no | |
1052 | fw |-- fw no no | |
1053 | bw |-- -- bw no | |
1054 | no |-- -- -- no. */ | |
1055 | ||
1056 | if (a == b) | |
1057 | return a; | |
1058 | ||
1059 | if (a == dir_both) | |
1060 | return b; | |
1061 | if (b == dir_both) | |
1062 | return a; | |
1063 | ||
1064 | return dir_none; | |
1065 | } | |
1066 | ||
1067 | /* Examine I1 and I2 and return: | |
1068 | - dir_forward if I1 can be replaced by I2, or | |
1069 | - dir_backward if I2 can be replaced by I1, or | |
1070 | - dir_both if both are the case. */ | |
1071 | ||
1072 | static enum replace_direction | |
c2fc5456 R |
1073 | old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2) |
1074 | { | |
1075 | rtx p1, p2; | |
1076 | ||
1077 | /* Verify that I1 and I2 are equivalent. */ | |
1078 | if (GET_CODE (i1) != GET_CODE (i2)) | |
472c95f5 | 1079 | return dir_none; |
c2fc5456 | 1080 | |
ba21aba3 DD |
1081 | /* __builtin_unreachable() may lead to empty blocks (ending with |
1082 | NOTE_INSN_BASIC_BLOCK). They may be crossjumped. */ | |
1083 | if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2)) | |
472c95f5 | 1084 | return dir_both; |
ba21aba3 | 1085 | |
9a08d230 RH |
1086 | /* ??? Do not allow cross-jumping between different stack levels. */ |
1087 | p1 = find_reg_note (i1, REG_ARGS_SIZE, NULL); | |
1088 | p2 = find_reg_note (i2, REG_ARGS_SIZE, NULL); | |
42aa5124 RH |
1089 | if (p1 && p2) |
1090 | { | |
1091 | p1 = XEXP (p1, 0); | |
1092 | p2 = XEXP (p2, 0); | |
1093 | if (!rtx_equal_p (p1, p2)) | |
1094 | return dir_none; | |
1095 | ||
1096 | /* ??? Worse, this adjustment had better be constant lest we | |
1097 | have differing incoming stack levels. */ | |
1098 | if (!frame_pointer_needed | |
1099 | && find_args_size_adjust (i1) == HOST_WIDE_INT_MIN) | |
1100 | return dir_none; | |
1101 | } | |
1102 | else if (p1 || p2) | |
9a08d230 RH |
1103 | return dir_none; |
1104 | ||
7752e522 | 1105 | p1 = PATTERN (i1); |
c2fc5456 R |
1106 | p2 = PATTERN (i2); |
1107 | ||
1108 | if (GET_CODE (p1) != GET_CODE (p2)) | |
472c95f5 | 1109 | return dir_none; |
c2fc5456 R |
1110 | |
1111 | /* If this is a CALL_INSN, compare register usage information. | |
1112 | If we don't check this on stack register machines, the two | |
1113 | CALL_INSNs might be merged leaving reg-stack.c with mismatching | |
1114 | numbers of stack registers in the same basic block. | |
1115 | If we don't check this on machines with delay slots, a delay slot may | |
1116 | be filled that clobbers a parameter expected by the subroutine. | |
1117 | ||
1118 | ??? We take the simple route for now and assume that if they're | |
31ce8a53 | 1119 | equal, they were constructed identically. |
c2fc5456 | 1120 | |
31ce8a53 BS |
1121 | Also check for identical exception regions. */ |
1122 | ||
1123 | if (CALL_P (i1)) | |
1124 | { | |
1125 | /* Ensure the same EH region. */ | |
1126 | rtx n1 = find_reg_note (i1, REG_EH_REGION, 0); | |
1127 | rtx n2 = find_reg_note (i2, REG_EH_REGION, 0); | |
1128 | ||
1129 | if (!n1 && n2) | |
472c95f5 | 1130 | return dir_none; |
31ce8a53 BS |
1131 | |
1132 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
472c95f5 | 1133 | return dir_none; |
31ce8a53 BS |
1134 | |
1135 | if (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1), | |
c22cacf3 | 1136 | CALL_INSN_FUNCTION_USAGE (i2)) |
31ce8a53 | 1137 | || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)) |
472c95f5 | 1138 | return dir_none; |
31ce8a53 | 1139 | } |
c2fc5456 R |
1140 | |
1141 | #ifdef STACK_REGS | |
1142 | /* If cross_jump_death_matters is not 0, the insn's mode | |
1143 | indicates whether or not the insn contains any stack-like | |
1144 | regs. */ | |
1145 | ||
1146 | if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1)) | |
1147 | { | |
1148 | /* If register stack conversion has already been done, then | |
c22cacf3 MS |
1149 | death notes must also be compared before it is certain that |
1150 | the two instruction streams match. */ | |
c2fc5456 R |
1151 | |
1152 | rtx note; | |
1153 | HARD_REG_SET i1_regset, i2_regset; | |
1154 | ||
1155 | CLEAR_HARD_REG_SET (i1_regset); | |
1156 | CLEAR_HARD_REG_SET (i2_regset); | |
1157 | ||
1158 | for (note = REG_NOTES (i1); note; note = XEXP (note, 1)) | |
1159 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1160 | SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0))); | |
1161 | ||
1162 | for (note = REG_NOTES (i2); note; note = XEXP (note, 1)) | |
1163 | if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0))) | |
1164 | SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0))); | |
1165 | ||
56b138ae | 1166 | if (!hard_reg_set_equal_p (i1_regset, i2_regset)) |
472c95f5 | 1167 | return dir_none; |
c2fc5456 R |
1168 | } |
1169 | #endif | |
1170 | ||
1171 | if (reload_completed | |
1172 | ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2)) | |
472c95f5 | 1173 | return dir_both; |
c2fc5456 | 1174 | |
472c95f5 | 1175 | return can_replace_by (i1, i2); |
c2fc5456 R |
1176 | } |
1177 | \f | |
31ce8a53 BS |
1178 | /* When comparing insns I1 and I2 in flow_find_cross_jump or |
1179 | flow_find_head_matching_sequence, ensure the notes match. */ | |
1180 | ||
1181 | static void | |
1182 | merge_notes (rtx i1, rtx i2) | |
1183 | { | |
1184 | /* If the merged insns have different REG_EQUAL notes, then | |
1185 | remove them. */ | |
1186 | rtx equiv1 = find_reg_equal_equiv_note (i1); | |
1187 | rtx equiv2 = find_reg_equal_equiv_note (i2); | |
1188 | ||
1189 | if (equiv1 && !equiv2) | |
1190 | remove_note (i1, equiv1); | |
1191 | else if (!equiv1 && equiv2) | |
1192 | remove_note (i2, equiv2); | |
1193 | else if (equiv1 && equiv2 | |
1194 | && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0))) | |
1195 | { | |
1196 | remove_note (i1, equiv1); | |
1197 | remove_note (i2, equiv2); | |
1198 | } | |
1199 | } | |
1200 | ||
823918ae TV |
1201 | /* Walks from I1 in BB1 backward till the next non-debug insn, and returns the |
1202 | resulting insn in I1, and the corresponding bb in BB1. At the head of a | |
1203 | bb, if there is a predecessor bb that reaches this bb via fallthru, and | |
1204 | FOLLOW_FALLTHRU, walks further in the predecessor bb and registers this in | |
1205 | DID_FALLTHRU. Otherwise, stops at the head of the bb. */ | |
1206 | ||
1207 | static void | |
1208 | walk_to_nondebug_insn (rtx *i1, basic_block *bb1, bool follow_fallthru, | |
1209 | bool *did_fallthru) | |
1210 | { | |
1211 | edge fallthru; | |
1212 | ||
1213 | *did_fallthru = false; | |
1214 | ||
1215 | /* Ignore notes. */ | |
1216 | while (!NONDEBUG_INSN_P (*i1)) | |
1217 | { | |
1218 | if (*i1 != BB_HEAD (*bb1)) | |
1219 | { | |
1220 | *i1 = PREV_INSN (*i1); | |
1221 | continue; | |
1222 | } | |
1223 | ||
1224 | if (!follow_fallthru) | |
1225 | return; | |
1226 | ||
1227 | fallthru = find_fallthru_edge ((*bb1)->preds); | |
1228 | if (!fallthru || fallthru->src == ENTRY_BLOCK_PTR_FOR_FUNCTION (cfun) | |
1229 | || !single_succ_p (fallthru->src)) | |
1230 | return; | |
1231 | ||
1232 | *bb1 = fallthru->src; | |
1233 | *i1 = BB_END (*bb1); | |
1234 | *did_fallthru = true; | |
1235 | } | |
1236 | } | |
1237 | ||
c2fc5456 | 1238 | /* Look through the insns at the end of BB1 and BB2 and find the longest |
472c95f5 TV |
1239 | sequence that are either equivalent, or allow forward or backward |
1240 | replacement. Store the first insns for that sequence in *F1 and *F2 and | |
1241 | return the sequence length. | |
1242 | ||
1243 | DIR_P indicates the allowed replacement direction on function entry, and | |
1244 | the actual replacement direction on function exit. If NULL, only equivalent | |
1245 | sequences are allowed. | |
c2fc5456 R |
1246 | |
1247 | To simplify callers of this function, if the blocks match exactly, | |
1248 | store the head of the blocks in *F1 and *F2. */ | |
1249 | ||
31ce8a53 | 1250 | int |
472c95f5 TV |
1251 | flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2, |
1252 | enum replace_direction *dir_p) | |
c2fc5456 R |
1253 | { |
1254 | rtx i1, i2, last1, last2, afterlast1, afterlast2; | |
1255 | int ninsns = 0; | |
2a562b0a | 1256 | rtx p1; |
472c95f5 | 1257 | enum replace_direction dir, last_dir, afterlast_dir; |
823918ae | 1258 | bool follow_fallthru, did_fallthru; |
472c95f5 TV |
1259 | |
1260 | if (dir_p) | |
1261 | dir = *dir_p; | |
1262 | else | |
1263 | dir = dir_both; | |
1264 | afterlast_dir = dir; | |
1265 | last_dir = afterlast_dir; | |
c2fc5456 R |
1266 | |
1267 | /* Skip simple jumps at the end of the blocks. Complex jumps still | |
1268 | need to be compared for equivalence, which we'll do below. */ | |
1269 | ||
1270 | i1 = BB_END (bb1); | |
1271 | last1 = afterlast1 = last2 = afterlast2 = NULL_RTX; | |
1272 | if (onlyjump_p (i1) | |
1273 | || (returnjump_p (i1) && !side_effects_p (PATTERN (i1)))) | |
1274 | { | |
1275 | last1 = i1; | |
1276 | i1 = PREV_INSN (i1); | |
1277 | } | |
1278 | ||
1279 | i2 = BB_END (bb2); | |
1280 | if (onlyjump_p (i2) | |
1281 | || (returnjump_p (i2) && !side_effects_p (PATTERN (i2)))) | |
1282 | { | |
1283 | last2 = i2; | |
1284 | /* Count everything except for unconditional jump as insn. */ | |
1285 | if (!simplejump_p (i2) && !returnjump_p (i2) && last1) | |
1286 | ninsns++; | |
1287 | i2 = PREV_INSN (i2); | |
1288 | } | |
1289 | ||
1290 | while (true) | |
1291 | { | |
823918ae TV |
1292 | /* In the following example, we can replace all jumps to C by jumps to A. |
1293 | ||
1294 | This removes 4 duplicate insns. | |
1295 | [bb A] insn1 [bb C] insn1 | |
1296 | insn2 insn2 | |
1297 | [bb B] insn3 insn3 | |
1298 | insn4 insn4 | |
1299 | jump_insn jump_insn | |
1300 | ||
1301 | We could also replace all jumps to A by jumps to C, but that leaves B | |
1302 | alive, and removes only 2 duplicate insns. In a subsequent crossjump | |
1303 | step, all jumps to B would be replaced with jumps to the middle of C, | |
1304 | achieving the same result with more effort. | |
1305 | So we allow only the first possibility, which means that we don't allow | |
1306 | fallthru in the block that's being replaced. */ | |
1307 | ||
1308 | follow_fallthru = dir_p && dir != dir_forward; | |
1309 | walk_to_nondebug_insn (&i1, &bb1, follow_fallthru, &did_fallthru); | |
1310 | if (did_fallthru) | |
1311 | dir = dir_backward; | |
1312 | ||
1313 | follow_fallthru = dir_p && dir != dir_backward; | |
1314 | walk_to_nondebug_insn (&i2, &bb2, follow_fallthru, &did_fallthru); | |
1315 | if (did_fallthru) | |
1316 | dir = dir_forward; | |
c2fc5456 R |
1317 | |
1318 | if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2)) | |
1319 | break; | |
1320 | ||
472c95f5 TV |
1321 | dir = merge_dir (dir, old_insns_match_p (0, i1, i2)); |
1322 | if (dir == dir_none || (!dir_p && dir != dir_both)) | |
c2fc5456 R |
1323 | break; |
1324 | ||
1325 | merge_memattrs (i1, i2); | |
1326 | ||
1327 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1328 | if (INSN_P (i1)) | |
1329 | { | |
31ce8a53 | 1330 | merge_notes (i1, i2); |
c2fc5456 R |
1331 | |
1332 | afterlast1 = last1, afterlast2 = last2; | |
1333 | last1 = i1, last2 = i2; | |
472c95f5 TV |
1334 | afterlast_dir = last_dir; |
1335 | last_dir = dir; | |
2a562b0a TV |
1336 | p1 = PATTERN (i1); |
1337 | if (!(GET_CODE (p1) == USE || GET_CODE (p1) == CLOBBER)) | |
1338 | ninsns++; | |
c2fc5456 R |
1339 | } |
1340 | ||
1341 | i1 = PREV_INSN (i1); | |
1342 | i2 = PREV_INSN (i2); | |
1343 | } | |
1344 | ||
1345 | #ifdef HAVE_cc0 | |
1346 | /* Don't allow the insn after a compare to be shared by | |
1347 | cross-jumping unless the compare is also shared. */ | |
1348 | if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1)) | |
472c95f5 | 1349 | last1 = afterlast1, last2 = afterlast2, last_dir = afterlast_dir, ninsns--; |
c2fc5456 R |
1350 | #endif |
1351 | ||
1352 | /* Include preceding notes and labels in the cross-jump. One, | |
1353 | this may bring us to the head of the blocks as requested above. | |
1354 | Two, it keeps line number notes as matched as may be. */ | |
1355 | if (ninsns) | |
1356 | { | |
823918ae | 1357 | bb1 = BLOCK_FOR_INSN (last1); |
b5b8b0ac | 1358 | while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1))) |
c2fc5456 R |
1359 | last1 = PREV_INSN (last1); |
1360 | ||
1361 | if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1))) | |
1362 | last1 = PREV_INSN (last1); | |
1363 | ||
823918ae | 1364 | bb2 = BLOCK_FOR_INSN (last2); |
b5b8b0ac | 1365 | while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2))) |
c2fc5456 R |
1366 | last2 = PREV_INSN (last2); |
1367 | ||
1368 | if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2))) | |
1369 | last2 = PREV_INSN (last2); | |
1370 | ||
1371 | *f1 = last1; | |
1372 | *f2 = last2; | |
1373 | } | |
1374 | ||
472c95f5 TV |
1375 | if (dir_p) |
1376 | *dir_p = last_dir; | |
c2fc5456 R |
1377 | return ninsns; |
1378 | } | |
1379 | ||
31ce8a53 BS |
1380 | /* Like flow_find_cross_jump, except start looking for a matching sequence from |
1381 | the head of the two blocks. Do not include jumps at the end. | |
1382 | If STOP_AFTER is nonzero, stop after finding that many matching | |
1383 | instructions. */ | |
1384 | ||
1385 | int | |
1386 | flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx *f1, | |
1387 | rtx *f2, int stop_after) | |
1388 | { | |
1389 | rtx i1, i2, last1, last2, beforelast1, beforelast2; | |
1390 | int ninsns = 0; | |
1391 | edge e; | |
1392 | edge_iterator ei; | |
1393 | int nehedges1 = 0, nehedges2 = 0; | |
1394 | ||
1395 | FOR_EACH_EDGE (e, ei, bb1->succs) | |
1396 | if (e->flags & EDGE_EH) | |
1397 | nehedges1++; | |
1398 | FOR_EACH_EDGE (e, ei, bb2->succs) | |
1399 | if (e->flags & EDGE_EH) | |
1400 | nehedges2++; | |
1401 | ||
1402 | i1 = BB_HEAD (bb1); | |
1403 | i2 = BB_HEAD (bb2); | |
1404 | last1 = beforelast1 = last2 = beforelast2 = NULL_RTX; | |
1405 | ||
1406 | while (true) | |
1407 | { | |
4ec5d4f5 | 1408 | /* Ignore notes, except NOTE_INSN_EPILOGUE_BEG. */ |
31ce8a53 | 1409 | while (!NONDEBUG_INSN_P (i1) && i1 != BB_END (bb1)) |
4ec5d4f5 BS |
1410 | { |
1411 | if (NOTE_P (i1) && NOTE_KIND (i1) == NOTE_INSN_EPILOGUE_BEG) | |
1412 | break; | |
1413 | i1 = NEXT_INSN (i1); | |
1414 | } | |
31ce8a53 BS |
1415 | |
1416 | while (!NONDEBUG_INSN_P (i2) && i2 != BB_END (bb2)) | |
4ec5d4f5 BS |
1417 | { |
1418 | if (NOTE_P (i2) && NOTE_KIND (i2) == NOTE_INSN_EPILOGUE_BEG) | |
1419 | break; | |
1420 | i2 = NEXT_INSN (i2); | |
1421 | } | |
31ce8a53 | 1422 | |
662592e1 BS |
1423 | if ((i1 == BB_END (bb1) && !NONDEBUG_INSN_P (i1)) |
1424 | || (i2 == BB_END (bb2) && !NONDEBUG_INSN_P (i2))) | |
1425 | break; | |
1426 | ||
31ce8a53 BS |
1427 | if (NOTE_P (i1) || NOTE_P (i2) |
1428 | || JUMP_P (i1) || JUMP_P (i2)) | |
1429 | break; | |
1430 | ||
1431 | /* A sanity check to make sure we're not merging insns with different | |
1432 | effects on EH. If only one of them ends a basic block, it shouldn't | |
1433 | have an EH edge; if both end a basic block, there should be the same | |
1434 | number of EH edges. */ | |
1435 | if ((i1 == BB_END (bb1) && i2 != BB_END (bb2) | |
1436 | && nehedges1 > 0) | |
1437 | || (i2 == BB_END (bb2) && i1 != BB_END (bb1) | |
1438 | && nehedges2 > 0) | |
1439 | || (i1 == BB_END (bb1) && i2 == BB_END (bb2) | |
1440 | && nehedges1 != nehedges2)) | |
1441 | break; | |
1442 | ||
472c95f5 | 1443 | if (old_insns_match_p (0, i1, i2) != dir_both) |
31ce8a53 BS |
1444 | break; |
1445 | ||
1446 | merge_memattrs (i1, i2); | |
1447 | ||
1448 | /* Don't begin a cross-jump with a NOTE insn. */ | |
1449 | if (INSN_P (i1)) | |
1450 | { | |
1451 | merge_notes (i1, i2); | |
1452 | ||
1453 | beforelast1 = last1, beforelast2 = last2; | |
1454 | last1 = i1, last2 = i2; | |
1455 | ninsns++; | |
1456 | } | |
1457 | ||
1458 | if (i1 == BB_END (bb1) || i2 == BB_END (bb2) | |
1459 | || (stop_after > 0 && ninsns == stop_after)) | |
1460 | break; | |
1461 | ||
1462 | i1 = NEXT_INSN (i1); | |
1463 | i2 = NEXT_INSN (i2); | |
1464 | } | |
1465 | ||
1466 | #ifdef HAVE_cc0 | |
1467 | /* Don't allow a compare to be shared by cross-jumping unless the insn | |
1468 | after the compare is also shared. */ | |
1469 | if (ninsns && reg_mentioned_p (cc0_rtx, last1) && sets_cc0_p (last1)) | |
1470 | last1 = beforelast1, last2 = beforelast2, ninsns--; | |
1471 | #endif | |
1472 | ||
1473 | if (ninsns) | |
1474 | { | |
1475 | *f1 = last1; | |
1476 | *f2 = last2; | |
1477 | } | |
1478 | ||
1479 | return ninsns; | |
1480 | } | |
1481 | ||
c2fc5456 R |
1482 | /* Return true iff outgoing edges of BB1 and BB2 match, together with |
1483 | the branch instruction. This means that if we commonize the control | |
1484 | flow before end of the basic block, the semantic remains unchanged. | |
402209ff JH |
1485 | |
1486 | We may assume that there exists one edge with a common destination. */ | |
1487 | ||
1488 | static bool | |
c2fc5456 | 1489 | outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) |
402209ff | 1490 | { |
0dd0e980 JH |
1491 | int nehedges1 = 0, nehedges2 = 0; |
1492 | edge fallthru1 = 0, fallthru2 = 0; | |
1493 | edge e1, e2; | |
628f6a4e | 1494 | edge_iterator ei; |
0dd0e980 | 1495 | |
484db665 BS |
1496 | /* If we performed shrink-wrapping, edges to the EXIT_BLOCK_PTR can |
1497 | only be distinguished for JUMP_INSNs. The two paths may differ in | |
1498 | whether they went through the prologue. Sibcalls are fine, we know | |
1499 | that we either didn't need or inserted an epilogue before them. */ | |
1500 | if (crtl->shrink_wrapped | |
1501 | && single_succ_p (bb1) && single_succ (bb1) == EXIT_BLOCK_PTR | |
1502 | && !JUMP_P (BB_END (bb1)) | |
1503 | && !(CALL_P (BB_END (bb1)) && SIBLING_CALL_P (BB_END (bb1)))) | |
1504 | return false; | |
1505 | ||
c04cf67b RH |
1506 | /* If BB1 has only one successor, we may be looking at either an |
1507 | unconditional jump, or a fake edge to exit. */ | |
c5cbcccf ZD |
1508 | if (single_succ_p (bb1) |
1509 | && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
4b4bf941 | 1510 | && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1)))) |
c5cbcccf ZD |
1511 | return (single_succ_p (bb2) |
1512 | && (single_succ_edge (bb2)->flags | |
1513 | & (EDGE_COMPLEX | EDGE_FAKE)) == 0 | |
4b4bf941 | 1514 | && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2)))); |
402209ff JH |
1515 | |
1516 | /* Match conditional jumps - this may get tricky when fallthru and branch | |
1517 | edges are crossed. */ | |
628f6a4e | 1518 | if (EDGE_COUNT (bb1->succs) == 2 |
a813c111 SB |
1519 | && any_condjump_p (BB_END (bb1)) |
1520 | && onlyjump_p (BB_END (bb1))) | |
402209ff | 1521 | { |
c2fc5456 R |
1522 | edge b1, f1, b2, f2; |
1523 | bool reverse, match; | |
1524 | rtx set1, set2, cond1, cond2; | |
1525 | enum rtx_code code1, code2; | |
1526 | ||
628f6a4e | 1527 | if (EDGE_COUNT (bb2->succs) != 2 |
a813c111 SB |
1528 | || !any_condjump_p (BB_END (bb2)) |
1529 | || !onlyjump_p (BB_END (bb2))) | |
0a2ed1f1 | 1530 | return false; |
c2fc5456 R |
1531 | |
1532 | b1 = BRANCH_EDGE (bb1); | |
1533 | b2 = BRANCH_EDGE (bb2); | |
1534 | f1 = FALLTHRU_EDGE (bb1); | |
1535 | f2 = FALLTHRU_EDGE (bb2); | |
1536 | ||
1537 | /* Get around possible forwarders on fallthru edges. Other cases | |
c22cacf3 | 1538 | should be optimized out already. */ |
c2fc5456 R |
1539 | if (FORWARDER_BLOCK_P (f1->dest)) |
1540 | f1 = single_succ_edge (f1->dest); | |
1541 | ||
1542 | if (FORWARDER_BLOCK_P (f2->dest)) | |
1543 | f2 = single_succ_edge (f2->dest); | |
1544 | ||
1545 | /* To simplify use of this function, return false if there are | |
1546 | unneeded forwarder blocks. These will get eliminated later | |
1547 | during cleanup_cfg. */ | |
1548 | if (FORWARDER_BLOCK_P (f1->dest) | |
1549 | || FORWARDER_BLOCK_P (f2->dest) | |
1550 | || FORWARDER_BLOCK_P (b1->dest) | |
1551 | || FORWARDER_BLOCK_P (b2->dest)) | |
1552 | return false; | |
1553 | ||
1554 | if (f1->dest == f2->dest && b1->dest == b2->dest) | |
1555 | reverse = false; | |
1556 | else if (f1->dest == b2->dest && b1->dest == f2->dest) | |
1557 | reverse = true; | |
1558 | else | |
1559 | return false; | |
1560 | ||
1561 | set1 = pc_set (BB_END (bb1)); | |
1562 | set2 = pc_set (BB_END (bb2)); | |
1563 | if ((XEXP (SET_SRC (set1), 1) == pc_rtx) | |
1564 | != (XEXP (SET_SRC (set2), 1) == pc_rtx)) | |
1565 | reverse = !reverse; | |
1566 | ||
1567 | cond1 = XEXP (SET_SRC (set1), 0); | |
1568 | cond2 = XEXP (SET_SRC (set2), 0); | |
1569 | code1 = GET_CODE (cond1); | |
1570 | if (reverse) | |
1571 | code2 = reversed_comparison_code (cond2, BB_END (bb2)); | |
1572 | else | |
1573 | code2 = GET_CODE (cond2); | |
1574 | ||
1575 | if (code2 == UNKNOWN) | |
1576 | return false; | |
1577 | ||
1578 | /* Verify codes and operands match. */ | |
1579 | match = ((code1 == code2 | |
1580 | && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0)) | |
1581 | && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1))) | |
1582 | || (code1 == swap_condition (code2) | |
1583 | && rtx_renumbered_equal_p (XEXP (cond1, 1), | |
1584 | XEXP (cond2, 0)) | |
1585 | && rtx_renumbered_equal_p (XEXP (cond1, 0), | |
1586 | XEXP (cond2, 1)))); | |
1587 | ||
1588 | /* If we return true, we will join the blocks. Which means that | |
1589 | we will only have one branch prediction bit to work with. Thus | |
1590 | we require the existing branches to have probabilities that are | |
1591 | roughly similar. */ | |
1592 | if (match | |
efd8f750 JH |
1593 | && optimize_bb_for_speed_p (bb1) |
1594 | && optimize_bb_for_speed_p (bb2)) | |
c2fc5456 R |
1595 | { |
1596 | int prob2; | |
1597 | ||
1598 | if (b1->dest == b2->dest) | |
1599 | prob2 = b2->probability; | |
1600 | else | |
1601 | /* Do not use f2 probability as f2 may be forwarded. */ | |
1602 | prob2 = REG_BR_PROB_BASE - b2->probability; | |
1603 | ||
1604 | /* Fail if the difference in probabilities is greater than 50%. | |
1605 | This rules out two well-predicted branches with opposite | |
1606 | outcomes. */ | |
1607 | if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2) | |
1608 | { | |
1609 | if (dump_file) | |
1610 | fprintf (dump_file, | |
1611 | "Outcomes of branch in bb %i and %i differ too much (%i %i)\n", | |
1612 | bb1->index, bb2->index, b1->probability, prob2); | |
1613 | ||
1614 | return false; | |
1615 | } | |
1616 | } | |
1617 | ||
1618 | if (dump_file && match) | |
1619 | fprintf (dump_file, "Conditionals in bb %i and %i match.\n", | |
1620 | bb1->index, bb2->index); | |
1621 | ||
1622 | return match; | |
402209ff JH |
1623 | } |
1624 | ||
09da1532 | 1625 | /* Generic case - we are seeing a computed jump, table jump or trapping |
0dd0e980 JH |
1626 | instruction. */ |
1627 | ||
39811184 JZ |
1628 | /* Check whether there are tablejumps in the end of BB1 and BB2. |
1629 | Return true if they are identical. */ | |
1630 | { | |
1631 | rtx label1, label2; | |
1632 | rtx table1, table2; | |
1633 | ||
a813c111 SB |
1634 | if (tablejump_p (BB_END (bb1), &label1, &table1) |
1635 | && tablejump_p (BB_END (bb2), &label2, &table2) | |
39811184 JZ |
1636 | && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2))) |
1637 | { | |
1638 | /* The labels should never be the same rtx. If they really are same | |
1639 | the jump tables are same too. So disable crossjumping of blocks BB1 | |
1640 | and BB2 because when deleting the common insns in the end of BB1 | |
6de9cd9a | 1641 | by delete_basic_block () the jump table would be deleted too. */ |
4af16369 | 1642 | /* If LABEL2 is referenced in BB1->END do not do anything |
39811184 JZ |
1643 | because we would loose information when replacing |
1644 | LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */ | |
a813c111 | 1645 | if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1))) |
39811184 JZ |
1646 | { |
1647 | /* Set IDENTICAL to true when the tables are identical. */ | |
1648 | bool identical = false; | |
1649 | rtx p1, p2; | |
1650 | ||
1651 | p1 = PATTERN (table1); | |
1652 | p2 = PATTERN (table2); | |
1653 | if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2)) | |
1654 | { | |
1655 | identical = true; | |
1656 | } | |
1657 | else if (GET_CODE (p1) == ADDR_DIFF_VEC | |
1658 | && (XVECLEN (p1, 1) == XVECLEN (p2, 1)) | |
1659 | && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2)) | |
1660 | && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3))) | |
1661 | { | |
1662 | int i; | |
1663 | ||
1664 | identical = true; | |
1665 | for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--) | |
1666 | if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i))) | |
1667 | identical = false; | |
1668 | } | |
1669 | ||
c2fc5456 | 1670 | if (identical) |
39811184 | 1671 | { |
c2fc5456 | 1672 | replace_label_data rr; |
39811184 JZ |
1673 | bool match; |
1674 | ||
c2fc5456 | 1675 | /* Temporarily replace references to LABEL1 with LABEL2 |
39811184 | 1676 | in BB1->END so that we could compare the instructions. */ |
c2fc5456 R |
1677 | rr.r1 = label1; |
1678 | rr.r2 = label2; | |
1679 | rr.update_label_nuses = false; | |
1680 | for_each_rtx (&BB_END (bb1), replace_label, &rr); | |
39811184 | 1681 | |
472c95f5 TV |
1682 | match = (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) |
1683 | == dir_both); | |
c263766c RH |
1684 | if (dump_file && match) |
1685 | fprintf (dump_file, | |
39811184 JZ |
1686 | "Tablejumps in bb %i and %i match.\n", |
1687 | bb1->index, bb2->index); | |
1688 | ||
c2fc5456 R |
1689 | /* Set the original label in BB1->END because when deleting |
1690 | a block whose end is a tablejump, the tablejump referenced | |
1691 | from the instruction is deleted too. */ | |
1692 | rr.r1 = label2; | |
1693 | rr.r2 = label1; | |
1694 | for_each_rtx (&BB_END (bb1), replace_label, &rr); | |
1695 | ||
39811184 JZ |
1696 | return match; |
1697 | } | |
1698 | } | |
1699 | return false; | |
1700 | } | |
1701 | } | |
39811184 | 1702 | |
0dd0e980 | 1703 | /* First ensure that the instructions match. There may be many outgoing |
39811184 | 1704 | edges so this test is generally cheaper. */ |
472c95f5 | 1705 | if (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) != dir_both) |
0dd0e980 JH |
1706 | return false; |
1707 | ||
1708 | /* Search the outgoing edges, ensure that the counts do match, find possible | |
1709 | fallthru and exception handling edges since these needs more | |
1710 | validation. */ | |
628f6a4e BE |
1711 | if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs)) |
1712 | return false; | |
1713 | ||
1714 | FOR_EACH_EDGE (e1, ei, bb1->succs) | |
0dd0e980 | 1715 | { |
628f6a4e | 1716 | e2 = EDGE_SUCC (bb2, ei.index); |
c22cacf3 | 1717 | |
0dd0e980 JH |
1718 | if (e1->flags & EDGE_EH) |
1719 | nehedges1++; | |
5f0d2358 | 1720 | |
0dd0e980 JH |
1721 | if (e2->flags & EDGE_EH) |
1722 | nehedges2++; | |
5f0d2358 | 1723 | |
0dd0e980 JH |
1724 | if (e1->flags & EDGE_FALLTHRU) |
1725 | fallthru1 = e1; | |
1726 | if (e2->flags & EDGE_FALLTHRU) | |
1727 | fallthru2 = e2; | |
1728 | } | |
5f0d2358 | 1729 | |
0dd0e980 | 1730 | /* If number of edges of various types does not match, fail. */ |
628f6a4e | 1731 | if (nehedges1 != nehedges2 |
5f0d2358 | 1732 | || (fallthru1 != 0) != (fallthru2 != 0)) |
0dd0e980 JH |
1733 | return false; |
1734 | ||
1735 | /* fallthru edges must be forwarded to the same destination. */ | |
1736 | if (fallthru1) | |
1737 | { | |
1738 | basic_block d1 = (forwarder_block_p (fallthru1->dest) | |
c5cbcccf | 1739 | ? single_succ (fallthru1->dest): fallthru1->dest); |
0dd0e980 | 1740 | basic_block d2 = (forwarder_block_p (fallthru2->dest) |
c5cbcccf | 1741 | ? single_succ (fallthru2->dest): fallthru2->dest); |
5f0d2358 | 1742 | |
0dd0e980 JH |
1743 | if (d1 != d2) |
1744 | return false; | |
1745 | } | |
5f0d2358 | 1746 | |
5f77fbd4 JJ |
1747 | /* Ensure the same EH region. */ |
1748 | { | |
a813c111 SB |
1749 | rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0); |
1750 | rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0); | |
5f0d2358 | 1751 | |
5f77fbd4 JJ |
1752 | if (!n1 && n2) |
1753 | return false; | |
1754 | ||
1755 | if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) | |
1756 | return false; | |
1757 | } | |
5f0d2358 | 1758 | |
38109dab GL |
1759 | /* The same checks as in try_crossjump_to_edge. It is required for RTL |
1760 | version of sequence abstraction. */ | |
1761 | FOR_EACH_EDGE (e1, ei, bb2->succs) | |
1762 | { | |
1763 | edge e2; | |
1764 | edge_iterator ei; | |
1765 | basic_block d1 = e1->dest; | |
1766 | ||
1767 | if (FORWARDER_BLOCK_P (d1)) | |
1768 | d1 = EDGE_SUCC (d1, 0)->dest; | |
1769 | ||
1770 | FOR_EACH_EDGE (e2, ei, bb1->succs) | |
1771 | { | |
1772 | basic_block d2 = e2->dest; | |
1773 | if (FORWARDER_BLOCK_P (d2)) | |
1774 | d2 = EDGE_SUCC (d2, 0)->dest; | |
1775 | if (d1 == d2) | |
1776 | break; | |
1777 | } | |
1778 | ||
1779 | if (!e2) | |
1780 | return false; | |
1781 | } | |
1782 | ||
0dd0e980 | 1783 | return true; |
402209ff JH |
1784 | } |
1785 | ||
38109dab GL |
1786 | /* Returns true if BB basic block has a preserve label. */ |
1787 | ||
1788 | static bool | |
1789 | block_has_preserve_label (basic_block bb) | |
1790 | { | |
1791 | return (bb | |
1792 | && block_label (bb) | |
1793 | && LABEL_PRESERVE_P (block_label (bb))); | |
1794 | } | |
1795 | ||
402209ff JH |
1796 | /* E1 and E2 are edges with the same destination block. Search their |
1797 | predecessors for common code. If found, redirect control flow from | |
bf22920b TV |
1798 | (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward), |
1799 | or the other way around (dir_backward). DIR specifies the allowed | |
1800 | replacement direction. */ | |
402209ff JH |
1801 | |
1802 | static bool | |
bf22920b TV |
1803 | try_crossjump_to_edge (int mode, edge e1, edge e2, |
1804 | enum replace_direction dir) | |
402209ff | 1805 | { |
c2fc5456 | 1806 | int nmatch; |
402209ff | 1807 | basic_block src1 = e1->src, src2 = e2->src; |
39587bb9 | 1808 | basic_block redirect_to, redirect_from, to_remove; |
823918ae | 1809 | basic_block osrc1, osrc2, redirect_edges_to, tmp; |
c2fc5456 | 1810 | rtx newpos1, newpos2; |
402209ff | 1811 | edge s; |
628f6a4e | 1812 | edge_iterator ei; |
c2fc5456 R |
1813 | |
1814 | newpos1 = newpos2 = NULL_RTX; | |
6de9cd9a | 1815 | |
750054a2 | 1816 | /* If we have partitioned hot/cold basic blocks, it is a bad idea |
c22cacf3 | 1817 | to try this optimization. |
8e8d5162 CT |
1818 | |
1819 | Basic block partitioning may result in some jumps that appear to | |
c22cacf3 MS |
1820 | be optimizable (or blocks that appear to be mergeable), but which really |
1821 | must be left untouched (they are required to make it safely across | |
1822 | partition boundaries). See the comments at the top of | |
8e8d5162 | 1823 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
750054a2 | 1824 | |
ef4375b2 | 1825 | if (flag_reorder_blocks_and_partition && reload_completed) |
750054a2 CT |
1826 | return false; |
1827 | ||
402209ff JH |
1828 | /* Search backward through forwarder blocks. We don't need to worry |
1829 | about multiple entry or chained forwarders, as they will be optimized | |
1830 | away. We do this to look past the unconditional jump following a | |
1831 | conditional jump that is required due to the current CFG shape. */ | |
c5cbcccf | 1832 | if (single_pred_p (src1) |
635559ab | 1833 | && FORWARDER_BLOCK_P (src1)) |
c5cbcccf | 1834 | e1 = single_pred_edge (src1), src1 = e1->src; |
5f0d2358 | 1835 | |
c5cbcccf | 1836 | if (single_pred_p (src2) |
635559ab | 1837 | && FORWARDER_BLOCK_P (src2)) |
c5cbcccf | 1838 | e2 = single_pred_edge (src2), src2 = e2->src; |
402209ff JH |
1839 | |
1840 | /* Nothing to do if we reach ENTRY, or a common source block. */ | |
1841 | if (src1 == ENTRY_BLOCK_PTR || src2 == ENTRY_BLOCK_PTR) | |
1842 | return false; | |
1843 | if (src1 == src2) | |
1844 | return false; | |
1845 | ||
1846 | /* Seeing more than 1 forwarder blocks would confuse us later... */ | |
635559ab | 1847 | if (FORWARDER_BLOCK_P (e1->dest) |
c5cbcccf | 1848 | && FORWARDER_BLOCK_P (single_succ (e1->dest))) |
402209ff | 1849 | return false; |
5f0d2358 | 1850 | |
635559ab | 1851 | if (FORWARDER_BLOCK_P (e2->dest) |
c5cbcccf | 1852 | && FORWARDER_BLOCK_P (single_succ (e2->dest))) |
402209ff JH |
1853 | return false; |
1854 | ||
1855 | /* Likewise with dead code (possibly newly created by the other optimizations | |
1856 | of cfg_cleanup). */ | |
628f6a4e | 1857 | if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0) |
402209ff JH |
1858 | return false; |
1859 | ||
402209ff | 1860 | /* Look for the common insn sequence, part the first ... */ |
c2fc5456 | 1861 | if (!outgoing_edges_match (mode, src1, src2)) |
402209ff JH |
1862 | return false; |
1863 | ||
1864 | /* ... and part the second. */ | |
472c95f5 | 1865 | nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir); |
12183e0f | 1866 | |
823918ae TV |
1867 | osrc1 = src1; |
1868 | osrc2 = src2; | |
1869 | if (newpos1 != NULL_RTX) | |
1870 | src1 = BLOCK_FOR_INSN (newpos1); | |
1871 | if (newpos2 != NULL_RTX) | |
1872 | src2 = BLOCK_FOR_INSN (newpos2); | |
1873 | ||
bf22920b TV |
1874 | if (dir == dir_backward) |
1875 | { | |
1876 | #define SWAP(T, X, Y) do { T tmp = (X); (X) = (Y); (Y) = tmp; } while (0) | |
1877 | SWAP (basic_block, osrc1, osrc2); | |
1878 | SWAP (basic_block, src1, src2); | |
1879 | SWAP (edge, e1, e2); | |
1880 | SWAP (rtx, newpos1, newpos2); | |
1881 | #undef SWAP | |
1882 | } | |
1883 | ||
12183e0f PH |
1884 | /* Don't proceed with the crossjump unless we found a sufficient number |
1885 | of matching instructions or the 'from' block was totally matched | |
1886 | (such that its predecessors will hopefully be redirected and the | |
1887 | block removed). */ | |
c2fc5456 R |
1888 | if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS)) |
1889 | && (newpos1 != BB_HEAD (src1))) | |
7d22e898 | 1890 | return false; |
402209ff | 1891 | |
75c40d56 | 1892 | /* Avoid deleting preserve label when redirecting ABNORMAL edges. */ |
38109dab GL |
1893 | if (block_has_preserve_label (e1->dest) |
1894 | && (e1->flags & EDGE_ABNORMAL)) | |
1895 | return false; | |
1896 | ||
39811184 JZ |
1897 | /* Here we know that the insns in the end of SRC1 which are common with SRC2 |
1898 | will be deleted. | |
1899 | If we have tablejumps in the end of SRC1 and SRC2 | |
1900 | they have been already compared for equivalence in outgoing_edges_match () | |
1901 | so replace the references to TABLE1 by references to TABLE2. */ | |
1902 | { | |
1903 | rtx label1, label2; | |
1904 | rtx table1, table2; | |
1905 | ||
823918ae TV |
1906 | if (tablejump_p (BB_END (osrc1), &label1, &table1) |
1907 | && tablejump_p (BB_END (osrc2), &label2, &table2) | |
39811184 JZ |
1908 | && label1 != label2) |
1909 | { | |
4af16369 | 1910 | replace_label_data rr; |
39811184 JZ |
1911 | rtx insn; |
1912 | ||
1913 | /* Replace references to LABEL1 with LABEL2. */ | |
1914 | rr.r1 = label1; | |
1915 | rr.r2 = label2; | |
4af16369 | 1916 | rr.update_label_nuses = true; |
39811184 JZ |
1917 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
1918 | { | |
1919 | /* Do not replace the label in SRC1->END because when deleting | |
1920 | a block whose end is a tablejump, the tablejump referenced | |
1921 | from the instruction is deleted too. */ | |
823918ae | 1922 | if (insn != BB_END (osrc1)) |
39811184 JZ |
1923 | for_each_rtx (&insn, replace_label, &rr); |
1924 | } | |
1925 | } | |
1926 | } | |
10d6c0d0 | 1927 | |
b604fe9b SB |
1928 | /* Avoid splitting if possible. We must always split when SRC2 has |
1929 | EH predecessor edges, or we may end up with basic blocks with both | |
1930 | normal and EH predecessor edges. */ | |
c2fc5456 | 1931 | if (newpos2 == BB_HEAD (src2) |
b604fe9b | 1932 | && !(EDGE_PRED (src2, 0)->flags & EDGE_EH)) |
402209ff JH |
1933 | redirect_to = src2; |
1934 | else | |
1935 | { | |
c2fc5456 | 1936 | if (newpos2 == BB_HEAD (src2)) |
b604fe9b SB |
1937 | { |
1938 | /* Skip possible basic block header. */ | |
c2fc5456 R |
1939 | if (LABEL_P (newpos2)) |
1940 | newpos2 = NEXT_INSN (newpos2); | |
b5b8b0ac AO |
1941 | while (DEBUG_INSN_P (newpos2)) |
1942 | newpos2 = NEXT_INSN (newpos2); | |
c2fc5456 R |
1943 | if (NOTE_P (newpos2)) |
1944 | newpos2 = NEXT_INSN (newpos2); | |
b5b8b0ac AO |
1945 | while (DEBUG_INSN_P (newpos2)) |
1946 | newpos2 = NEXT_INSN (newpos2); | |
b604fe9b SB |
1947 | } |
1948 | ||
c263766c RH |
1949 | if (dump_file) |
1950 | fprintf (dump_file, "Splitting bb %i before %i insns\n", | |
0b17ab2f | 1951 | src2->index, nmatch); |
c2fc5456 | 1952 | redirect_to = split_block (src2, PREV_INSN (newpos2))->dest; |
402209ff JH |
1953 | } |
1954 | ||
c263766c | 1955 | if (dump_file) |
c2fc5456 R |
1956 | fprintf (dump_file, |
1957 | "Cross jumping from bb %i to bb %i; %i common insns\n", | |
1958 | src1->index, src2->index, nmatch); | |
402209ff | 1959 | |
6fc0bb99 | 1960 | /* We may have some registers visible through the block. */ |
6fb5fa3c | 1961 | df_set_bb_dirty (redirect_to); |
402209ff | 1962 | |
823918ae TV |
1963 | if (osrc2 == src2) |
1964 | redirect_edges_to = redirect_to; | |
1965 | else | |
1966 | redirect_edges_to = osrc2; | |
1967 | ||
402209ff | 1968 | /* Recompute the frequencies and counts of outgoing edges. */ |
823918ae | 1969 | FOR_EACH_EDGE (s, ei, redirect_edges_to->succs) |
402209ff JH |
1970 | { |
1971 | edge s2; | |
628f6a4e | 1972 | edge_iterator ei; |
402209ff JH |
1973 | basic_block d = s->dest; |
1974 | ||
635559ab | 1975 | if (FORWARDER_BLOCK_P (d)) |
c5cbcccf | 1976 | d = single_succ (d); |
5f0d2358 | 1977 | |
628f6a4e | 1978 | FOR_EACH_EDGE (s2, ei, src1->succs) |
402209ff JH |
1979 | { |
1980 | basic_block d2 = s2->dest; | |
635559ab | 1981 | if (FORWARDER_BLOCK_P (d2)) |
c5cbcccf | 1982 | d2 = single_succ (d2); |
402209ff JH |
1983 | if (d == d2) |
1984 | break; | |
1985 | } | |
5f0d2358 | 1986 | |
402209ff JH |
1987 | s->count += s2->count; |
1988 | ||
1989 | /* Take care to update possible forwarder blocks. We verified | |
c22cacf3 MS |
1990 | that there is no more than one in the chain, so we can't run |
1991 | into infinite loop. */ | |
635559ab | 1992 | if (FORWARDER_BLOCK_P (s->dest)) |
402209ff | 1993 | { |
c5cbcccf | 1994 | single_succ_edge (s->dest)->count += s2->count; |
402209ff JH |
1995 | s->dest->count += s2->count; |
1996 | s->dest->frequency += EDGE_FREQUENCY (s); | |
1997 | } | |
5f0d2358 | 1998 | |
635559ab | 1999 | if (FORWARDER_BLOCK_P (s2->dest)) |
402209ff | 2000 | { |
c5cbcccf ZD |
2001 | single_succ_edge (s2->dest)->count -= s2->count; |
2002 | if (single_succ_edge (s2->dest)->count < 0) | |
2003 | single_succ_edge (s2->dest)->count = 0; | |
402209ff JH |
2004 | s2->dest->count -= s2->count; |
2005 | s2->dest->frequency -= EDGE_FREQUENCY (s); | |
b446e5a2 JH |
2006 | if (s2->dest->frequency < 0) |
2007 | s2->dest->frequency = 0; | |
2008 | if (s2->dest->count < 0) | |
2009 | s2->dest->count = 0; | |
402209ff | 2010 | } |
5f0d2358 | 2011 | |
823918ae | 2012 | if (!redirect_edges_to->frequency && !src1->frequency) |
402209ff JH |
2013 | s->probability = (s->probability + s2->probability) / 2; |
2014 | else | |
5f0d2358 | 2015 | s->probability |
823918ae | 2016 | = ((s->probability * redirect_edges_to->frequency + |
5f0d2358 | 2017 | s2->probability * src1->frequency) |
823918ae | 2018 | / (redirect_edges_to->frequency + src1->frequency)); |
402209ff JH |
2019 | } |
2020 | ||
52982a97 EB |
2021 | /* Adjust count and frequency for the block. An earlier jump |
2022 | threading pass may have left the profile in an inconsistent | |
2023 | state (see update_bb_profile_for_threading) so we must be | |
2024 | prepared for overflows. */ | |
823918ae TV |
2025 | tmp = redirect_to; |
2026 | do | |
2027 | { | |
2028 | tmp->count += src1->count; | |
2029 | tmp->frequency += src1->frequency; | |
2030 | if (tmp->frequency > BB_FREQ_MAX) | |
2031 | tmp->frequency = BB_FREQ_MAX; | |
2032 | if (tmp == redirect_edges_to) | |
2033 | break; | |
2034 | tmp = find_fallthru_edge (tmp->succs)->dest; | |
2035 | } | |
2036 | while (true); | |
2037 | update_br_prob_note (redirect_edges_to); | |
402209ff JH |
2038 | |
2039 | /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */ | |
2040 | ||
c2fc5456 R |
2041 | /* Skip possible basic block header. */ |
2042 | if (LABEL_P (newpos1)) | |
2043 | newpos1 = NEXT_INSN (newpos1); | |
b5b8b0ac AO |
2044 | |
2045 | while (DEBUG_INSN_P (newpos1)) | |
2046 | newpos1 = NEXT_INSN (newpos1); | |
2047 | ||
cd9c1ca8 | 2048 | if (NOTE_INSN_BASIC_BLOCK_P (newpos1)) |
c2fc5456 R |
2049 | newpos1 = NEXT_INSN (newpos1); |
2050 | ||
b5b8b0ac AO |
2051 | while (DEBUG_INSN_P (newpos1)) |
2052 | newpos1 = NEXT_INSN (newpos1); | |
2053 | ||
c2fc5456 | 2054 | redirect_from = split_block (src1, PREV_INSN (newpos1))->src; |
c5cbcccf | 2055 | to_remove = single_succ (redirect_from); |
402209ff | 2056 | |
c5cbcccf | 2057 | redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to); |
f470c378 | 2058 | delete_basic_block (to_remove); |
402209ff | 2059 | |
39587bb9 | 2060 | update_forwarder_flag (redirect_from); |
7cbd12b8 JJ |
2061 | if (redirect_to != src2) |
2062 | update_forwarder_flag (src2); | |
635559ab | 2063 | |
402209ff JH |
2064 | return true; |
2065 | } | |
2066 | ||
2067 | /* Search the predecessors of BB for common insn sequences. When found, | |
2068 | share code between them by redirecting control flow. Return true if | |
2069 | any changes made. */ | |
2070 | ||
2071 | static bool | |
d329e058 | 2072 | try_crossjump_bb (int mode, basic_block bb) |
402209ff | 2073 | { |
628f6a4e | 2074 | edge e, e2, fallthru; |
402209ff | 2075 | bool changed; |
628f6a4e | 2076 | unsigned max, ix, ix2; |
402209ff | 2077 | |
f63d1bf7 | 2078 | /* Nothing to do if there is not at least two incoming edges. */ |
628f6a4e | 2079 | if (EDGE_COUNT (bb->preds) < 2) |
402209ff JH |
2080 | return false; |
2081 | ||
bbcb0c05 SB |
2082 | /* Don't crossjump if this block ends in a computed jump, |
2083 | unless we are optimizing for size. */ | |
efd8f750 | 2084 | if (optimize_bb_for_size_p (bb) |
bbcb0c05 SB |
2085 | && bb != EXIT_BLOCK_PTR |
2086 | && computed_jump_p (BB_END (bb))) | |
2087 | return false; | |
2088 | ||
750054a2 CT |
2089 | /* If we are partitioning hot/cold basic blocks, we don't want to |
2090 | mess up unconditional or indirect jumps that cross between hot | |
c22cacf3 MS |
2091 | and cold sections. |
2092 | ||
8e8d5162 | 2093 | Basic block partitioning may result in some jumps that appear to |
c22cacf3 MS |
2094 | be optimizable (or blocks that appear to be mergeable), but which really |
2095 | must be left untouched (they are required to make it safely across | |
2096 | partition boundaries). See the comments at the top of | |
8e8d5162 CT |
2097 | bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */ |
2098 | ||
c22cacf3 MS |
2099 | if (BB_PARTITION (EDGE_PRED (bb, 0)->src) != |
2100 | BB_PARTITION (EDGE_PRED (bb, 1)->src) | |
87c8b4be | 2101 | || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING)) |
750054a2 CT |
2102 | return false; |
2103 | ||
402209ff JH |
2104 | /* It is always cheapest to redirect a block that ends in a branch to |
2105 | a block that falls through into BB, as that adds no branches to the | |
2106 | program. We'll try that combination first. */ | |
5f24e0dc RH |
2107 | fallthru = NULL; |
2108 | max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES); | |
628f6a4e BE |
2109 | |
2110 | if (EDGE_COUNT (bb->preds) > max) | |
2111 | return false; | |
2112 | ||
0fd4b31d | 2113 | fallthru = find_fallthru_edge (bb->preds); |
402209ff JH |
2114 | |
2115 | changed = false; | |
0248bceb | 2116 | for (ix = 0; ix < EDGE_COUNT (bb->preds);) |
402209ff | 2117 | { |
0248bceb | 2118 | e = EDGE_PRED (bb, ix); |
628f6a4e | 2119 | ix++; |
402209ff | 2120 | |
c1e3e2d9 SB |
2121 | /* As noted above, first try with the fallthru predecessor (or, a |
2122 | fallthru predecessor if we are in cfglayout mode). */ | |
402209ff JH |
2123 | if (fallthru) |
2124 | { | |
2125 | /* Don't combine the fallthru edge into anything else. | |
2126 | If there is a match, we'll do it the other way around. */ | |
2127 | if (e == fallthru) | |
2128 | continue; | |
7cf240d5 JH |
2129 | /* If nothing changed since the last attempt, there is nothing |
2130 | we can do. */ | |
2131 | if (!first_pass | |
4ec5d4f5 BS |
2132 | && !((e->src->flags & BB_MODIFIED) |
2133 | || (fallthru->src->flags & BB_MODIFIED))) | |
7cf240d5 | 2134 | continue; |
402209ff | 2135 | |
bf22920b | 2136 | if (try_crossjump_to_edge (mode, e, fallthru, dir_forward)) |
402209ff JH |
2137 | { |
2138 | changed = true; | |
628f6a4e | 2139 | ix = 0; |
402209ff JH |
2140 | continue; |
2141 | } | |
2142 | } | |
2143 | ||
2144 | /* Non-obvious work limiting check: Recognize that we're going | |
2145 | to call try_crossjump_bb on every basic block. So if we have | |
2146 | two blocks with lots of outgoing edges (a switch) and they | |
2147 | share lots of common destinations, then we would do the | |
2148 | cross-jump check once for each common destination. | |
2149 | ||
2150 | Now, if the blocks actually are cross-jump candidates, then | |
2151 | all of their destinations will be shared. Which means that | |
2152 | we only need check them for cross-jump candidacy once. We | |
2153 | can eliminate redundant checks of crossjump(A,B) by arbitrarily | |
2154 | choosing to do the check from the block for which the edge | |
2155 | in question is the first successor of A. */ | |
628f6a4e | 2156 | if (EDGE_SUCC (e->src, 0) != e) |
402209ff JH |
2157 | continue; |
2158 | ||
0248bceb | 2159 | for (ix2 = 0; ix2 < EDGE_COUNT (bb->preds); ix2++) |
402209ff | 2160 | { |
0248bceb | 2161 | e2 = EDGE_PRED (bb, ix2); |
402209ff JH |
2162 | |
2163 | if (e2 == e) | |
2164 | continue; | |
2165 | ||
2166 | /* We've already checked the fallthru edge above. */ | |
2167 | if (e2 == fallthru) | |
2168 | continue; | |
2169 | ||
402209ff JH |
2170 | /* The "first successor" check above only prevents multiple |
2171 | checks of crossjump(A,B). In order to prevent redundant | |
2172 | checks of crossjump(B,A), require that A be the block | |
2173 | with the lowest index. */ | |
0b17ab2f | 2174 | if (e->src->index > e2->src->index) |
402209ff JH |
2175 | continue; |
2176 | ||
7cf240d5 JH |
2177 | /* If nothing changed since the last attempt, there is nothing |
2178 | we can do. */ | |
2179 | if (!first_pass | |
4ec5d4f5 BS |
2180 | && !((e->src->flags & BB_MODIFIED) |
2181 | || (e2->src->flags & BB_MODIFIED))) | |
7cf240d5 JH |
2182 | continue; |
2183 | ||
bf22920b TV |
2184 | /* Both e and e2 are not fallthru edges, so we can crossjump in either |
2185 | direction. */ | |
2186 | if (try_crossjump_to_edge (mode, e, e2, dir_both)) | |
402209ff JH |
2187 | { |
2188 | changed = true; | |
628f6a4e | 2189 | ix = 0; |
402209ff JH |
2190 | break; |
2191 | } | |
2192 | } | |
2193 | } | |
2194 | ||
c1e3e2d9 SB |
2195 | if (changed) |
2196 | crossjumps_occured = true; | |
2197 | ||
402209ff JH |
2198 | return changed; |
2199 | } | |
2200 | ||
4ec5d4f5 BS |
2201 | /* Search the successors of BB for common insn sequences. When found, |
2202 | share code between them by moving it across the basic block | |
2203 | boundary. Return true if any changes made. */ | |
2204 | ||
2205 | static bool | |
2206 | try_head_merge_bb (basic_block bb) | |
2207 | { | |
2208 | basic_block final_dest_bb = NULL; | |
2209 | int max_match = INT_MAX; | |
2210 | edge e0; | |
2211 | rtx *headptr, *currptr, *nextptr; | |
2212 | bool changed, moveall; | |
2213 | unsigned ix; | |
2214 | rtx e0_last_head, cond, move_before; | |
2215 | unsigned nedges = EDGE_COUNT (bb->succs); | |
2216 | rtx jump = BB_END (bb); | |
2217 | regset live, live_union; | |
2218 | ||
2219 | /* Nothing to do if there is not at least two outgoing edges. */ | |
2220 | if (nedges < 2) | |
2221 | return false; | |
2222 | ||
2223 | /* Don't crossjump if this block ends in a computed jump, | |
2224 | unless we are optimizing for size. */ | |
2225 | if (optimize_bb_for_size_p (bb) | |
2226 | && bb != EXIT_BLOCK_PTR | |
2227 | && computed_jump_p (BB_END (bb))) | |
2228 | return false; | |
2229 | ||
2230 | cond = get_condition (jump, &move_before, true, false); | |
2231 | if (cond == NULL_RTX) | |
43052d45 BS |
2232 | { |
2233 | #ifdef HAVE_cc0 | |
2234 | if (reg_mentioned_p (cc0_rtx, jump)) | |
2235 | move_before = prev_nonnote_nondebug_insn (jump); | |
2236 | else | |
2237 | #endif | |
2238 | move_before = jump; | |
2239 | } | |
4ec5d4f5 BS |
2240 | |
2241 | for (ix = 0; ix < nedges; ix++) | |
2242 | if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR) | |
2243 | return false; | |
2244 | ||
2245 | for (ix = 0; ix < nedges; ix++) | |
2246 | { | |
2247 | edge e = EDGE_SUCC (bb, ix); | |
2248 | basic_block other_bb = e->dest; | |
2249 | ||
2250 | if (df_get_bb_dirty (other_bb)) | |
2251 | { | |
2252 | block_was_dirty = true; | |
2253 | return false; | |
2254 | } | |
2255 | ||
2256 | if (e->flags & EDGE_ABNORMAL) | |
2257 | return false; | |
2258 | ||
2259 | /* Normally, all destination blocks must only be reachable from this | |
2260 | block, i.e. they must have one incoming edge. | |
2261 | ||
2262 | There is one special case we can handle, that of multiple consecutive | |
2263 | jumps where the first jumps to one of the targets of the second jump. | |
2264 | This happens frequently in switch statements for default labels. | |
2265 | The structure is as follows: | |
2266 | FINAL_DEST_BB | |
2267 | .... | |
2268 | if (cond) jump A; | |
2269 | fall through | |
2270 | BB | |
2271 | jump with targets A, B, C, D... | |
2272 | A | |
2273 | has two incoming edges, from FINAL_DEST_BB and BB | |
2274 | ||
2275 | In this case, we can try to move the insns through BB and into | |
2276 | FINAL_DEST_BB. */ | |
2277 | if (EDGE_COUNT (other_bb->preds) != 1) | |
2278 | { | |
2279 | edge incoming_edge, incoming_bb_other_edge; | |
2280 | edge_iterator ei; | |
2281 | ||
2282 | if (final_dest_bb != NULL | |
2283 | || EDGE_COUNT (other_bb->preds) != 2) | |
2284 | return false; | |
2285 | ||
2286 | /* We must be able to move the insns across the whole block. */ | |
2287 | move_before = BB_HEAD (bb); | |
2288 | while (!NONDEBUG_INSN_P (move_before)) | |
2289 | move_before = NEXT_INSN (move_before); | |
2290 | ||
2291 | if (EDGE_COUNT (bb->preds) != 1) | |
2292 | return false; | |
2293 | incoming_edge = EDGE_PRED (bb, 0); | |
2294 | final_dest_bb = incoming_edge->src; | |
2295 | if (EDGE_COUNT (final_dest_bb->succs) != 2) | |
2296 | return false; | |
2297 | FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs) | |
2298 | if (incoming_bb_other_edge != incoming_edge) | |
2299 | break; | |
2300 | if (incoming_bb_other_edge->dest != other_bb) | |
2301 | return false; | |
2302 | } | |
2303 | } | |
2304 | ||
2305 | e0 = EDGE_SUCC (bb, 0); | |
2306 | e0_last_head = NULL_RTX; | |
2307 | changed = false; | |
2308 | ||
2309 | for (ix = 1; ix < nedges; ix++) | |
2310 | { | |
2311 | edge e = EDGE_SUCC (bb, ix); | |
2312 | rtx e0_last, e_last; | |
2313 | int nmatch; | |
2314 | ||
2315 | nmatch = flow_find_head_matching_sequence (e0->dest, e->dest, | |
2316 | &e0_last, &e_last, 0); | |
2317 | if (nmatch == 0) | |
2318 | return false; | |
2319 | ||
2320 | if (nmatch < max_match) | |
2321 | { | |
2322 | max_match = nmatch; | |
2323 | e0_last_head = e0_last; | |
2324 | } | |
2325 | } | |
2326 | ||
2327 | /* If we matched an entire block, we probably have to avoid moving the | |
2328 | last insn. */ | |
2329 | if (max_match > 0 | |
2330 | && e0_last_head == BB_END (e0->dest) | |
2331 | && (find_reg_note (e0_last_head, REG_EH_REGION, 0) | |
2332 | || control_flow_insn_p (e0_last_head))) | |
2333 | { | |
2334 | max_match--; | |
2335 | if (max_match == 0) | |
2336 | return false; | |
2337 | do | |
2338 | e0_last_head = prev_real_insn (e0_last_head); | |
2339 | while (DEBUG_INSN_P (e0_last_head)); | |
2340 | } | |
2341 | ||
2342 | if (max_match == 0) | |
2343 | return false; | |
2344 | ||
2345 | /* We must find a union of the live registers at each of the end points. */ | |
2346 | live = BITMAP_ALLOC (NULL); | |
2347 | live_union = BITMAP_ALLOC (NULL); | |
2348 | ||
2349 | currptr = XNEWVEC (rtx, nedges); | |
2350 | headptr = XNEWVEC (rtx, nedges); | |
2351 | nextptr = XNEWVEC (rtx, nedges); | |
2352 | ||
2353 | for (ix = 0; ix < nedges; ix++) | |
2354 | { | |
2355 | int j; | |
2356 | basic_block merge_bb = EDGE_SUCC (bb, ix)->dest; | |
2357 | rtx head = BB_HEAD (merge_bb); | |
2358 | ||
2359 | while (!NONDEBUG_INSN_P (head)) | |
2360 | head = NEXT_INSN (head); | |
2361 | headptr[ix] = head; | |
2362 | currptr[ix] = head; | |
2363 | ||
2364 | /* Compute the end point and live information */ | |
2365 | for (j = 1; j < max_match; j++) | |
2366 | do | |
2367 | head = NEXT_INSN (head); | |
2368 | while (!NONDEBUG_INSN_P (head)); | |
2369 | simulate_backwards_to_point (merge_bb, live, head); | |
2370 | IOR_REG_SET (live_union, live); | |
2371 | } | |
2372 | ||
2373 | /* If we're moving across two blocks, verify the validity of the | |
2374 | first move, then adjust the target and let the loop below deal | |
2375 | with the final move. */ | |
2376 | if (final_dest_bb != NULL) | |
2377 | { | |
2378 | rtx move_upto; | |
2379 | ||
2380 | moveall = can_move_insns_across (currptr[0], e0_last_head, move_before, | |
2381 | jump, e0->dest, live_union, | |
2382 | NULL, &move_upto); | |
2383 | if (!moveall) | |
2384 | { | |
2385 | if (move_upto == NULL_RTX) | |
2386 | goto out; | |
2387 | ||
2388 | while (e0_last_head != move_upto) | |
2389 | { | |
2390 | df_simulate_one_insn_backwards (e0->dest, e0_last_head, | |
2391 | live_union); | |
2392 | e0_last_head = PREV_INSN (e0_last_head); | |
2393 | } | |
2394 | } | |
2395 | if (e0_last_head == NULL_RTX) | |
2396 | goto out; | |
2397 | ||
2398 | jump = BB_END (final_dest_bb); | |
2399 | cond = get_condition (jump, &move_before, true, false); | |
2400 | if (cond == NULL_RTX) | |
43052d45 BS |
2401 | { |
2402 | #ifdef HAVE_cc0 | |
2403 | if (reg_mentioned_p (cc0_rtx, jump)) | |
2404 | move_before = prev_nonnote_nondebug_insn (jump); | |
2405 | else | |
2406 | #endif | |
2407 | move_before = jump; | |
2408 | } | |
4ec5d4f5 BS |
2409 | } |
2410 | ||
2411 | do | |
2412 | { | |
2413 | rtx move_upto; | |
2414 | moveall = can_move_insns_across (currptr[0], e0_last_head, | |
2415 | move_before, jump, e0->dest, live_union, | |
2416 | NULL, &move_upto); | |
2417 | if (!moveall && move_upto == NULL_RTX) | |
2418 | { | |
2419 | if (jump == move_before) | |
2420 | break; | |
2421 | ||
2422 | /* Try again, using a different insertion point. */ | |
2423 | move_before = jump; | |
2424 | ||
2425 | #ifdef HAVE_cc0 | |
2426 | /* Don't try moving before a cc0 user, as that may invalidate | |
2427 | the cc0. */ | |
2428 | if (reg_mentioned_p (cc0_rtx, jump)) | |
2429 | break; | |
2430 | #endif | |
2431 | ||
2432 | continue; | |
2433 | } | |
2434 | ||
2435 | if (final_dest_bb && !moveall) | |
2436 | /* We haven't checked whether a partial move would be OK for the first | |
2437 | move, so we have to fail this case. */ | |
2438 | break; | |
2439 | ||
2440 | changed = true; | |
2441 | for (;;) | |
2442 | { | |
2443 | if (currptr[0] == move_upto) | |
2444 | break; | |
2445 | for (ix = 0; ix < nedges; ix++) | |
2446 | { | |
2447 | rtx curr = currptr[ix]; | |
2448 | do | |
2449 | curr = NEXT_INSN (curr); | |
2450 | while (!NONDEBUG_INSN_P (curr)); | |
2451 | currptr[ix] = curr; | |
2452 | } | |
2453 | } | |
2454 | ||
2455 | /* If we can't currently move all of the identical insns, remember | |
2456 | each insn after the range that we'll merge. */ | |
2457 | if (!moveall) | |
2458 | for (ix = 0; ix < nedges; ix++) | |
2459 | { | |
2460 | rtx curr = currptr[ix]; | |
2461 | do | |
2462 | curr = NEXT_INSN (curr); | |
2463 | while (!NONDEBUG_INSN_P (curr)); | |
2464 | nextptr[ix] = curr; | |
2465 | } | |
2466 | ||
2467 | reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before)); | |
2468 | df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest); | |
2469 | if (final_dest_bb != NULL) | |
2470 | df_set_bb_dirty (final_dest_bb); | |
2471 | df_set_bb_dirty (bb); | |
2472 | for (ix = 1; ix < nedges; ix++) | |
2473 | { | |
2474 | df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest); | |
2475 | delete_insn_chain (headptr[ix], currptr[ix], false); | |
2476 | } | |
2477 | if (!moveall) | |
2478 | { | |
2479 | if (jump == move_before) | |
2480 | break; | |
2481 | ||
2482 | /* For the unmerged insns, try a different insertion point. */ | |
2483 | move_before = jump; | |
2484 | ||
2485 | #ifdef HAVE_cc0 | |
2486 | /* Don't try moving before a cc0 user, as that may invalidate | |
2487 | the cc0. */ | |
2488 | if (reg_mentioned_p (cc0_rtx, jump)) | |
2489 | break; | |
2490 | #endif | |
2491 | ||
2492 | for (ix = 0; ix < nedges; ix++) | |
2493 | currptr[ix] = headptr[ix] = nextptr[ix]; | |
2494 | } | |
2495 | } | |
2496 | while (!moveall); | |
2497 | ||
2498 | out: | |
2499 | free (currptr); | |
2500 | free (headptr); | |
2501 | free (nextptr); | |
2502 | ||
2503 | crossjumps_occured |= changed; | |
2504 | ||
2505 | return changed; | |
2506 | } | |
2507 | ||
7752e522 JJ |
2508 | /* Return true if BB contains just bb note, or bb note followed |
2509 | by only DEBUG_INSNs. */ | |
2510 | ||
2511 | static bool | |
2512 | trivially_empty_bb_p (basic_block bb) | |
2513 | { | |
2514 | rtx insn = BB_END (bb); | |
2515 | ||
2516 | while (1) | |
2517 | { | |
2518 | if (insn == BB_HEAD (bb)) | |
2519 | return true; | |
2520 | if (!DEBUG_INSN_P (insn)) | |
2521 | return false; | |
2522 | insn = PREV_INSN (insn); | |
2523 | } | |
2524 | } | |
2525 | ||
402209ff JH |
2526 | /* Do simple CFG optimizations - basic block merging, simplifying of jump |
2527 | instructions etc. Return nonzero if changes were made. */ | |
2528 | ||
2529 | static bool | |
d329e058 | 2530 | try_optimize_cfg (int mode) |
402209ff | 2531 | { |
402209ff JH |
2532 | bool changed_overall = false; |
2533 | bool changed; | |
2534 | int iterations = 0; | |
ec3ae3da | 2535 | basic_block bb, b, next; |
402209ff | 2536 | |
6fb5fa3c | 2537 | if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING)) |
38c1593d JH |
2538 | clear_bb_flags (); |
2539 | ||
c1e3e2d9 SB |
2540 | crossjumps_occured = false; |
2541 | ||
2dd2d53e SB |
2542 | FOR_EACH_BB (bb) |
2543 | update_forwarder_flag (bb); | |
2544 | ||
245f1bfa | 2545 | if (! targetm.cannot_modify_jumps_p ()) |
402209ff | 2546 | { |
7cf240d5 | 2547 | first_pass = true; |
e4ec2cac AO |
2548 | /* Attempt to merge blocks as made possible by edge removal. If |
2549 | a block has only one successor, and the successor has only | |
2550 | one predecessor, they may be combined. */ | |
2551 | do | |
402209ff | 2552 | { |
4ec5d4f5 | 2553 | block_was_dirty = false; |
e4ec2cac AO |
2554 | changed = false; |
2555 | iterations++; | |
2556 | ||
c263766c RH |
2557 | if (dump_file) |
2558 | fprintf (dump_file, | |
e4ec2cac AO |
2559 | "\n\ntry_optimize_cfg iteration %i\n\n", |
2560 | iterations); | |
402209ff | 2561 | |
e0082a72 | 2562 | for (b = ENTRY_BLOCK_PTR->next_bb; b != EXIT_BLOCK_PTR;) |
402209ff | 2563 | { |
e0082a72 | 2564 | basic_block c; |
e4ec2cac AO |
2565 | edge s; |
2566 | bool changed_here = false; | |
5f0d2358 | 2567 | |
468059bc DD |
2568 | /* Delete trivially dead basic blocks. This is either |
2569 | blocks with no predecessors, or empty blocks with no | |
1e211590 DD |
2570 | successors. However if the empty block with no |
2571 | successors is the successor of the ENTRY_BLOCK, it is | |
2572 | kept. This ensures that the ENTRY_BLOCK will have a | |
2573 | successor which is a precondition for many RTL | |
2574 | passes. Empty blocks may result from expanding | |
468059bc DD |
2575 | __builtin_unreachable (). */ |
2576 | if (EDGE_COUNT (b->preds) == 0 | |
1e211590 | 2577 | || (EDGE_COUNT (b->succs) == 0 |
7752e522 | 2578 | && trivially_empty_bb_p (b) |
1e211590 | 2579 | && single_succ_edge (ENTRY_BLOCK_PTR)->dest != b)) |
e4ec2cac | 2580 | { |
f6366fc7 | 2581 | c = b->prev_bb; |
f1de5107 | 2582 | if (EDGE_COUNT (b->preds) > 0) |
3b5fda81 JJ |
2583 | { |
2584 | edge e; | |
2585 | edge_iterator ei; | |
2586 | ||
f1de5107 JJ |
2587 | if (current_ir_type () == IR_RTL_CFGLAYOUT) |
2588 | { | |
bcc708fc MM |
2589 | if (BB_FOOTER (b) |
2590 | && BARRIER_P (BB_FOOTER (b))) | |
f1de5107 JJ |
2591 | FOR_EACH_EDGE (e, ei, b->preds) |
2592 | if ((e->flags & EDGE_FALLTHRU) | |
bcc708fc | 2593 | && BB_FOOTER (e->src) == NULL) |
f1de5107 | 2594 | { |
bcc708fc | 2595 | if (BB_FOOTER (b)) |
f1de5107 | 2596 | { |
bcc708fc MM |
2597 | BB_FOOTER (e->src) = BB_FOOTER (b); |
2598 | BB_FOOTER (b) = NULL; | |
f1de5107 JJ |
2599 | } |
2600 | else | |
2601 | { | |
2602 | start_sequence (); | |
bcc708fc | 2603 | BB_FOOTER (e->src) = emit_barrier (); |
f1de5107 JJ |
2604 | end_sequence (); |
2605 | } | |
2606 | } | |
2607 | } | |
2608 | else | |
2609 | { | |
2610 | rtx last = get_last_bb_insn (b); | |
2611 | if (last && BARRIER_P (last)) | |
2612 | FOR_EACH_EDGE (e, ei, b->preds) | |
2613 | if ((e->flags & EDGE_FALLTHRU)) | |
2614 | emit_barrier_after (BB_END (e->src)); | |
2615 | } | |
3b5fda81 | 2616 | } |
f470c378 | 2617 | delete_basic_block (b); |
bef16e87 | 2618 | changed = true; |
83bd032b ZD |
2619 | /* Avoid trying to remove ENTRY_BLOCK_PTR. */ |
2620 | b = (c == ENTRY_BLOCK_PTR ? c->next_bb : c); | |
2621 | continue; | |
e4ec2cac | 2622 | } |
402209ff | 2623 | |
6ce2bcb7 | 2624 | /* Remove code labels no longer used. */ |
c5cbcccf ZD |
2625 | if (single_pred_p (b) |
2626 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
2627 | && !(single_pred_edge (b)->flags & EDGE_COMPLEX) | |
4b4bf941 | 2628 | && LABEL_P (BB_HEAD (b)) |
e4ec2cac AO |
2629 | /* If the previous block ends with a branch to this |
2630 | block, we can't delete the label. Normally this | |
2631 | is a condjump that is yet to be simplified, but | |
2632 | if CASE_DROPS_THRU, this can be a tablejump with | |
2633 | some element going to the same place as the | |
2634 | default (fallthru). */ | |
c5cbcccf ZD |
2635 | && (single_pred (b) == ENTRY_BLOCK_PTR |
2636 | || !JUMP_P (BB_END (single_pred (b))) | |
a813c111 | 2637 | || ! label_is_jump_target_p (BB_HEAD (b), |
c5cbcccf | 2638 | BB_END (single_pred (b))))) |
e4ec2cac | 2639 | { |
03fbe718 | 2640 | delete_insn (BB_HEAD (b)); |
c263766c RH |
2641 | if (dump_file) |
2642 | fprintf (dump_file, "Deleted label in block %i.\n", | |
0b17ab2f | 2643 | b->index); |
e4ec2cac | 2644 | } |
402209ff | 2645 | |
e4ec2cac | 2646 | /* If we fall through an empty block, we can remove it. */ |
9be94227 | 2647 | if (!(mode & (CLEANUP_CFGLAYOUT | CLEANUP_NO_INSN_DEL)) |
c5cbcccf ZD |
2648 | && single_pred_p (b) |
2649 | && (single_pred_edge (b)->flags & EDGE_FALLTHRU) | |
4b4bf941 | 2650 | && !LABEL_P (BB_HEAD (b)) |
e4ec2cac AO |
2651 | && FORWARDER_BLOCK_P (b) |
2652 | /* Note that forwarder_block_p true ensures that | |
2653 | there is a successor for this block. */ | |
c5cbcccf | 2654 | && (single_succ_edge (b)->flags & EDGE_FALLTHRU) |
24bd1a0b | 2655 | && n_basic_blocks > NUM_FIXED_BLOCKS + 1) |
e4ec2cac | 2656 | { |
c263766c RH |
2657 | if (dump_file) |
2658 | fprintf (dump_file, | |
e4ec2cac | 2659 | "Deleting fallthru block %i.\n", |
0b17ab2f | 2660 | b->index); |
e4ec2cac | 2661 | |
f6366fc7 | 2662 | c = b->prev_bb == ENTRY_BLOCK_PTR ? b->next_bb : b->prev_bb; |
c5cbcccf ZD |
2663 | redirect_edge_succ_nodup (single_pred_edge (b), |
2664 | single_succ (b)); | |
f470c378 | 2665 | delete_basic_block (b); |
e4ec2cac AO |
2666 | changed = true; |
2667 | b = c; | |
1e211590 | 2668 | continue; |
e4ec2cac | 2669 | } |
5f0d2358 | 2670 | |
50a36e42 | 2671 | /* Merge B with its single successor, if any. */ |
c5cbcccf ZD |
2672 | if (single_succ_p (b) |
2673 | && (s = single_succ_edge (b)) | |
ec3ae3da JH |
2674 | && !(s->flags & EDGE_COMPLEX) |
2675 | && (c = s->dest) != EXIT_BLOCK_PTR | |
c5cbcccf | 2676 | && single_pred_p (c) |
bc35512f JH |
2677 | && b != c) |
2678 | { | |
2679 | /* When not in cfg_layout mode use code aware of reordering | |
2680 | INSN. This code possibly creates new basic blocks so it | |
2681 | does not fit merge_blocks interface and is kept here in | |
2682 | hope that it will become useless once more of compiler | |
2683 | is transformed to use cfg_layout mode. */ | |
c22cacf3 | 2684 | |
bc35512f JH |
2685 | if ((mode & CLEANUP_CFGLAYOUT) |
2686 | && can_merge_blocks_p (b, c)) | |
2687 | { | |
2688 | merge_blocks (b, c); | |
2689 | update_forwarder_flag (b); | |
2690 | changed_here = true; | |
2691 | } | |
2692 | else if (!(mode & CLEANUP_CFGLAYOUT) | |
2693 | /* If the jump insn has side effects, | |
2694 | we can't kill the edge. */ | |
4b4bf941 | 2695 | && (!JUMP_P (BB_END (b)) |
e24e7211 | 2696 | || (reload_completed |
a813c111 | 2697 | ? simplejump_p (BB_END (b)) |
e4efa971 JH |
2698 | : (onlyjump_p (BB_END (b)) |
2699 | && !tablejump_p (BB_END (b), | |
2700 | NULL, NULL)))) | |
bc35512f JH |
2701 | && (next = merge_blocks_move (s, b, c, mode))) |
2702 | { | |
2703 | b = next; | |
2704 | changed_here = true; | |
2705 | } | |
ec3ae3da | 2706 | } |
e4ec2cac AO |
2707 | |
2708 | /* Simplify branch over branch. */ | |
bc35512f JH |
2709 | if ((mode & CLEANUP_EXPENSIVE) |
2710 | && !(mode & CLEANUP_CFGLAYOUT) | |
2711 | && try_simplify_condjump (b)) | |
38c1593d | 2712 | changed_here = true; |
402209ff | 2713 | |
e4ec2cac AO |
2714 | /* If B has a single outgoing edge, but uses a |
2715 | non-trivial jump instruction without side-effects, we | |
2716 | can either delete the jump entirely, or replace it | |
3348b696 | 2717 | with a simple unconditional jump. */ |
c5cbcccf ZD |
2718 | if (single_succ_p (b) |
2719 | && single_succ (b) != EXIT_BLOCK_PTR | |
a813c111 | 2720 | && onlyjump_p (BB_END (b)) |
750054a2 | 2721 | && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX) |
c5cbcccf ZD |
2722 | && try_redirect_by_replacing_jump (single_succ_edge (b), |
2723 | single_succ (b), | |
20b4e8ae | 2724 | (mode & CLEANUP_CFGLAYOUT) != 0)) |
e4ec2cac | 2725 | { |
e4ec2cac AO |
2726 | update_forwarder_flag (b); |
2727 | changed_here = true; | |
2728 | } | |
402209ff | 2729 | |
e4ec2cac AO |
2730 | /* Simplify branch to branch. */ |
2731 | if (try_forward_edges (mode, b)) | |
afe8b6ec EB |
2732 | { |
2733 | update_forwarder_flag (b); | |
2734 | changed_here = true; | |
2735 | } | |
402209ff | 2736 | |
e4ec2cac AO |
2737 | /* Look for shared code between blocks. */ |
2738 | if ((mode & CLEANUP_CROSSJUMP) | |
2739 | && try_crossjump_bb (mode, b)) | |
2740 | changed_here = true; | |
402209ff | 2741 | |
4ec5d4f5 BS |
2742 | if ((mode & CLEANUP_CROSSJUMP) |
2743 | /* This can lengthen register lifetimes. Do it only after | |
2744 | reload. */ | |
2745 | && reload_completed | |
2746 | && try_head_merge_bb (b)) | |
2747 | changed_here = true; | |
2748 | ||
e4ec2cac AO |
2749 | /* Don't get confused by the index shift caused by |
2750 | deleting blocks. */ | |
2751 | if (!changed_here) | |
e0082a72 | 2752 | b = b->next_bb; |
e4ec2cac AO |
2753 | else |
2754 | changed = true; | |
2755 | } | |
402209ff | 2756 | |
e4ec2cac AO |
2757 | if ((mode & CLEANUP_CROSSJUMP) |
2758 | && try_crossjump_bb (mode, EXIT_BLOCK_PTR)) | |
402209ff | 2759 | changed = true; |
402209ff | 2760 | |
4ec5d4f5 BS |
2761 | if (block_was_dirty) |
2762 | { | |
2763 | /* This should only be set by head-merging. */ | |
2764 | gcc_assert (mode & CLEANUP_CROSSJUMP); | |
2765 | df_analyze (); | |
2766 | } | |
2767 | ||
402209ff | 2768 | #ifdef ENABLE_CHECKING |
e4ec2cac AO |
2769 | if (changed) |
2770 | verify_flow_info (); | |
402209ff JH |
2771 | #endif |
2772 | ||
e4ec2cac | 2773 | changed_overall |= changed; |
7cf240d5 | 2774 | first_pass = false; |
e4ec2cac AO |
2775 | } |
2776 | while (changed); | |
402209ff | 2777 | } |
ca6c03ca | 2778 | |
2dd2d53e SB |
2779 | FOR_ALL_BB (b) |
2780 | b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK); | |
635559ab | 2781 | |
402209ff JH |
2782 | return changed_overall; |
2783 | } | |
2784 | \f | |
6d2f8887 | 2785 | /* Delete all unreachable basic blocks. */ |
4262e623 | 2786 | |
969d70ca | 2787 | bool |
d329e058 | 2788 | delete_unreachable_blocks (void) |
402209ff | 2789 | { |
402209ff | 2790 | bool changed = false; |
b5b8b0ac | 2791 | basic_block b, prev_bb; |
402209ff JH |
2792 | |
2793 | find_unreachable_blocks (); | |
2794 | ||
b5b8b0ac AO |
2795 | /* When we're in GIMPLE mode and there may be debug insns, we should |
2796 | delete blocks in reverse dominator order, so as to get a chance | |
2797 | to substitute all released DEFs into debug stmts. If we don't | |
2798 | have dominators information, walking blocks backward gets us a | |
2799 | better chance of retaining most debug information than | |
2800 | otherwise. */ | |
2801 | if (MAY_HAVE_DEBUG_STMTS && current_ir_type () == IR_GIMPLE | |
2802 | && dom_info_available_p (CDI_DOMINATORS)) | |
402209ff | 2803 | { |
b5b8b0ac AO |
2804 | for (b = EXIT_BLOCK_PTR->prev_bb; b != ENTRY_BLOCK_PTR; b = prev_bb) |
2805 | { | |
2806 | prev_bb = b->prev_bb; | |
2807 | ||
2808 | if (!(b->flags & BB_REACHABLE)) | |
2809 | { | |
2810 | /* Speed up the removal of blocks that don't dominate | |
2811 | others. Walking backwards, this should be the common | |
2812 | case. */ | |
2813 | if (!first_dom_son (CDI_DOMINATORS, b)) | |
2814 | delete_basic_block (b); | |
2815 | else | |
2816 | { | |
2817 | VEC (basic_block, heap) *h | |
2818 | = get_all_dominated_blocks (CDI_DOMINATORS, b); | |
2819 | ||
2820 | while (VEC_length (basic_block, h)) | |
2821 | { | |
2822 | b = VEC_pop (basic_block, h); | |
2823 | ||
2824 | prev_bb = b->prev_bb; | |
0b17ab2f | 2825 | |
b5b8b0ac AO |
2826 | gcc_assert (!(b->flags & BB_REACHABLE)); |
2827 | ||
2828 | delete_basic_block (b); | |
2829 | } | |
2830 | ||
2831 | VEC_free (basic_block, heap, h); | |
2832 | } | |
2833 | ||
2834 | changed = true; | |
2835 | } | |
2836 | } | |
2837 | } | |
2838 | else | |
2839 | { | |
2840 | for (b = EXIT_BLOCK_PTR->prev_bb; b != ENTRY_BLOCK_PTR; b = prev_bb) | |
6a58eee9 | 2841 | { |
b5b8b0ac AO |
2842 | prev_bb = b->prev_bb; |
2843 | ||
2844 | if (!(b->flags & BB_REACHABLE)) | |
2845 | { | |
2846 | delete_basic_block (b); | |
2847 | changed = true; | |
2848 | } | |
6a58eee9 | 2849 | } |
402209ff JH |
2850 | } |
2851 | ||
2852 | if (changed) | |
2853 | tidy_fallthru_edges (); | |
2854 | return changed; | |
2855 | } | |
6fb5fa3c DB |
2856 | |
2857 | /* Delete any jump tables never referenced. We can't delete them at the | |
2858 | time of removing tablejump insn as they are referenced by the preceding | |
2859 | insns computing the destination, so we delay deleting and garbagecollect | |
2860 | them once life information is computed. */ | |
2861 | void | |
2862 | delete_dead_jumptables (void) | |
2863 | { | |
2864 | basic_block bb; | |
2865 | ||
2866 | /* A dead jump table does not belong to any basic block. Scan insns | |
2867 | between two adjacent basic blocks. */ | |
2868 | FOR_EACH_BB (bb) | |
2869 | { | |
2870 | rtx insn, next; | |
2871 | ||
2872 | for (insn = NEXT_INSN (BB_END (bb)); | |
2873 | insn && !NOTE_INSN_BASIC_BLOCK_P (insn); | |
2874 | insn = next) | |
2875 | { | |
2876 | next = NEXT_INSN (insn); | |
2877 | if (LABEL_P (insn) | |
2878 | && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn) | |
481683e1 | 2879 | && JUMP_TABLE_DATA_P (next)) |
6fb5fa3c DB |
2880 | { |
2881 | rtx label = insn, jump = next; | |
2882 | ||
2883 | if (dump_file) | |
2884 | fprintf (dump_file, "Dead jumptable %i removed\n", | |
2885 | INSN_UID (insn)); | |
2886 | ||
2887 | next = NEXT_INSN (next); | |
2888 | delete_insn (jump); | |
2889 | delete_insn (label); | |
2890 | } | |
2891 | } | |
2892 | } | |
2893 | } | |
2894 | ||
402209ff JH |
2895 | \f |
2896 | /* Tidy the CFG by deleting unreachable code and whatnot. */ | |
2897 | ||
2898 | bool | |
d329e058 | 2899 | cleanup_cfg (int mode) |
402209ff | 2900 | { |
402209ff JH |
2901 | bool changed = false; |
2902 | ||
aeceeb06 SB |
2903 | /* Set the cfglayout mode flag here. We could update all the callers |
2904 | but that is just inconvenient, especially given that we eventually | |
2905 | want to have cfglayout mode as the default. */ | |
2906 | if (current_ir_type () == IR_RTL_CFGLAYOUT) | |
2907 | mode |= CLEANUP_CFGLAYOUT; | |
2908 | ||
402209ff | 2909 | timevar_push (TV_CLEANUP_CFG); |
3dec4024 JH |
2910 | if (delete_unreachable_blocks ()) |
2911 | { | |
2912 | changed = true; | |
2913 | /* We've possibly created trivially dead code. Cleanup it right | |
95bd1dd7 | 2914 | now to introduce more opportunities for try_optimize_cfg. */ |
6fb5fa3c | 2915 | if (!(mode & (CLEANUP_NO_INSN_DEL)) |
3dec4024 | 2916 | && !reload_completed) |
62e5bf5d | 2917 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); |
3dec4024 | 2918 | } |
bf77398c ZD |
2919 | |
2920 | compact_blocks (); | |
2921 | ||
c1e3e2d9 SB |
2922 | /* To tail-merge blocks ending in the same noreturn function (e.g. |
2923 | a call to abort) we have to insert fake edges to exit. Do this | |
2924 | here once. The fake edges do not interfere with any other CFG | |
2925 | cleanups. */ | |
2926 | if (mode & CLEANUP_CROSSJUMP) | |
2927 | add_noreturn_fake_exit_edges (); | |
2928 | ||
7d817ebc DE |
2929 | if (!dbg_cnt (cfg_cleanup)) |
2930 | return changed; | |
2931 | ||
3dec4024 JH |
2932 | while (try_optimize_cfg (mode)) |
2933 | { | |
2934 | delete_unreachable_blocks (), changed = true; | |
c1e3e2d9 | 2935 | if (!(mode & CLEANUP_NO_INSN_DEL)) |
3dec4024 | 2936 | { |
c1e3e2d9 SB |
2937 | /* Try to remove some trivially dead insns when doing an expensive |
2938 | cleanup. But delete_trivially_dead_insns doesn't work after | |
2939 | reload (it only handles pseudos) and run_fast_dce is too costly | |
2940 | to run in every iteration. | |
2941 | ||
2942 | For effective cross jumping, we really want to run a fast DCE to | |
2943 | clean up any dead conditions, or they get in the way of performing | |
2944 | useful tail merges. | |
2945 | ||
2946 | Other transformations in cleanup_cfg are not so sensitive to dead | |
2947 | code, so delete_trivially_dead_insns or even doing nothing at all | |
2948 | is good enough. */ | |
2949 | if ((mode & CLEANUP_EXPENSIVE) && !reload_completed | |
2950 | && !delete_trivially_dead_insns (get_insns (), max_reg_num ())) | |
3dec4024 | 2951 | break; |
4ec5d4f5 | 2952 | if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occured) |
f842d54f | 2953 | run_fast_dce (); |
3dec4024 JH |
2954 | } |
2955 | else | |
2956 | break; | |
3dec4024 | 2957 | } |
402209ff | 2958 | |
c1e3e2d9 SB |
2959 | if (mode & CLEANUP_CROSSJUMP) |
2960 | remove_fake_exit_edges (); | |
2961 | ||
6fb5fa3c DB |
2962 | /* Don't call delete_dead_jumptables in cfglayout mode, because |
2963 | that function assumes that jump tables are in the insns stream. | |
2964 | But we also don't _have_ to delete dead jumptables in cfglayout | |
2965 | mode because we shouldn't even be looking at things that are | |
2966 | not in a basic block. Dead jumptables are cleaned up when | |
2967 | going out of cfglayout mode. */ | |
2968 | if (!(mode & CLEANUP_CFGLAYOUT)) | |
2969 | delete_dead_jumptables (); | |
2970 | ||
7d776ee2 RG |
2971 | /* ??? We probably do this way too often. */ |
2972 | if (current_loops | |
2973 | && (changed | |
2974 | || (mode & CLEANUP_CFG_CHANGED))) | |
2975 | { | |
2976 | bitmap changed_bbs; | |
2977 | timevar_push (TV_REPAIR_LOOPS); | |
2978 | /* The above doesn't preserve dominance info if available. */ | |
2979 | gcc_assert (!dom_info_available_p (CDI_DOMINATORS)); | |
2980 | calculate_dominance_info (CDI_DOMINATORS); | |
2981 | changed_bbs = BITMAP_ALLOC (NULL); | |
2982 | fix_loop_structure (changed_bbs); | |
2983 | BITMAP_FREE (changed_bbs); | |
2984 | free_dominance_info (CDI_DOMINATORS); | |
2985 | timevar_pop (TV_REPAIR_LOOPS); | |
2986 | } | |
2987 | ||
402209ff JH |
2988 | timevar_pop (TV_CLEANUP_CFG); |
2989 | ||
402209ff JH |
2990 | return changed; |
2991 | } | |
ef330312 | 2992 | \f |
c2924966 | 2993 | static unsigned int |
ef330312 PB |
2994 | rest_of_handle_jump2 (void) |
2995 | { | |
ef330312 | 2996 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); |
ef330312 | 2997 | if (dump_file) |
5b4fdb20 | 2998 | dump_flow_info (dump_file, dump_flags); |
59994160 | 2999 | cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0) |
c22cacf3 | 3000 | | (flag_thread_jumps ? CLEANUP_THREADING : 0)); |
c2924966 | 3001 | return 0; |
ef330312 PB |
3002 | } |
3003 | ||
3004 | ||
8ddbbcae | 3005 | struct rtl_opt_pass pass_jump2 = |
ef330312 | 3006 | { |
8ddbbcae JH |
3007 | { |
3008 | RTL_PASS, | |
ef330312 | 3009 | "jump", /* name */ |
c22cacf3 MS |
3010 | NULL, /* gate */ |
3011 | rest_of_handle_jump2, /* execute */ | |
ef330312 PB |
3012 | NULL, /* sub */ |
3013 | NULL, /* next */ | |
3014 | 0, /* static_pass_number */ | |
3015 | TV_JUMP, /* tv_id */ | |
3016 | 0, /* properties_required */ | |
3017 | 0, /* properties_provided */ | |
3018 | 0, /* properties_destroyed */ | |
3019 | TODO_ggc_collect, /* todo_flags_start */ | |
22c5fa5f | 3020 | TODO_verify_rtl_sharing, /* todo_flags_finish */ |
8ddbbcae | 3021 | } |
ef330312 | 3022 | }; |