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1 : : /* Control flow optimization code for GNU compiler.
2 : : Copyright (C) 1987-2024 Free Software Foundation, Inc.
3 : :
4 : : This file is part of GCC.
5 : :
6 : : GCC is free software; you can redistribute it and/or modify it under
7 : : the terms of the GNU General Public License as published by the Free
8 : : Software Foundation; either version 3, or (at your option) any later
9 : : version.
10 : :
11 : : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 : : WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 : : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 : : for more details.
15 : :
16 : : You should have received a copy of the GNU General Public License
17 : : along with GCC; see the file COPYING3. If not see
18 : : <http://www.gnu.org/licenses/>. */
19 : :
20 : : /* This file contains optimizer of the control flow. The main entry point is
21 : : cleanup_cfg. Following optimizations are performed:
22 : :
23 : : - Unreachable blocks removal
24 : : - Edge forwarding (edge to the forwarder block is forwarded to its
25 : : successor. Simplification of the branch instruction is performed by
26 : : underlying infrastructure so branch can be converted to simplejump or
27 : : eliminated).
28 : : - Cross jumping (tail merging)
29 : : - Conditional jump-around-simplejump simplification
30 : : - Basic block merging. */
31 : :
32 : : #include "config.h"
33 : : #include "system.h"
34 : : #include "coretypes.h"
35 : : #include "backend.h"
36 : : #include "target.h"
37 : : #include "rtl.h"
38 : : #include "tree.h"
39 : : #include "cfghooks.h"
40 : : #include "df.h"
41 : : #include "memmodel.h"
42 : : #include "tm_p.h"
43 : : #include "insn-config.h"
44 : : #include "emit-rtl.h"
45 : : #include "cselib.h"
46 : : #include "tree-pass.h"
47 : : #include "cfgloop.h"
48 : : #include "cfgrtl.h"
49 : : #include "cfganal.h"
50 : : #include "cfgbuild.h"
51 : : #include "cfgcleanup.h"
52 : : #include "dce.h"
53 : : #include "dbgcnt.h"
54 : : #include "rtl-iter.h"
55 : : #include "regs.h"
56 : : #include "function-abi.h"
57 : :
58 : : #define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK)
59 : :
60 : : /* Set to true when we are running first pass of try_optimize_cfg loop. */
61 : : static bool first_pass;
62 : :
63 : : /* Set to true if crossjumps occurred in the latest run of try_optimize_cfg. */
64 : : static bool crossjumps_occurred;
65 : :
66 : : /* Set to true if we couldn't run an optimization due to stale liveness
67 : : information; we should run df_analyze to enable more opportunities. */
68 : : static bool block_was_dirty;
69 : :
70 : : static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction);
71 : : static bool try_crossjump_bb (int, basic_block);
72 : : static bool outgoing_edges_match (int, basic_block, basic_block);
73 : : static enum replace_direction old_insns_match_p (int, rtx_insn *, rtx_insn *);
74 : :
75 : : static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block);
76 : : static void merge_blocks_move_successor_nojumps (basic_block, basic_block);
77 : : static bool try_optimize_cfg (int);
78 : : static bool try_simplify_condjump (basic_block);
79 : : static bool try_forward_edges (int, basic_block);
80 : : static edge thread_jump (edge, basic_block);
81 : : static bool mark_effect (rtx, bitmap);
82 : : static void notice_new_block (basic_block);
83 : : static void update_forwarder_flag (basic_block);
84 : : static void merge_memattrs (rtx, rtx);
85 : :
86 : : /* Set flags for newly created block. */
87 : :
88 : : static void
89 : 22672 : notice_new_block (basic_block bb)
90 : : {
91 : 22672 : if (!bb)
92 : : return;
93 : :
94 : 15724 : if (forwarder_block_p (bb))
95 : 15724 : bb->flags |= BB_FORWARDER_BLOCK;
96 : : }
97 : :
98 : : /* Recompute forwarder flag after block has been modified. */
99 : :
100 : : static void
101 : 289347611 : update_forwarder_flag (basic_block bb)
102 : : {
103 : 289347611 : if (forwarder_block_p (bb))
104 : 15654824 : bb->flags |= BB_FORWARDER_BLOCK;
105 : : else
106 : 273692787 : bb->flags &= ~BB_FORWARDER_BLOCK;
107 : 289347611 : }
108 : :
109 : : /* Simplify a conditional jump around an unconditional jump.
110 : : Return true if something changed. */
111 : :
112 : : static bool
113 : 31102660 : try_simplify_condjump (basic_block cbranch_block)
114 : : {
115 : 31102660 : basic_block jump_block, jump_dest_block, cbranch_dest_block;
116 : 31102660 : edge cbranch_jump_edge, cbranch_fallthru_edge;
117 : 31102660 : rtx_insn *cbranch_insn;
118 : :
119 : : /* Verify that there are exactly two successors. */
120 : 31102660 : if (EDGE_COUNT (cbranch_block->succs) != 2)
121 : : return false;
122 : :
123 : : /* Verify that we've got a normal conditional branch at the end
124 : : of the block. */
125 : 15520101 : cbranch_insn = BB_END (cbranch_block);
126 : 15520101 : if (!any_condjump_p (cbranch_insn))
127 : : return false;
128 : :
129 : 13519738 : cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block);
130 : 13519738 : cbranch_jump_edge = BRANCH_EDGE (cbranch_block);
131 : :
132 : : /* The next block must not have multiple predecessors, must not
133 : : be the last block in the function, and must contain just the
134 : : unconditional jump. */
135 : 13519738 : jump_block = cbranch_fallthru_edge->dest;
136 : 44614741 : if (!single_pred_p (jump_block)
137 : 12091011 : || jump_block->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
138 : 25454183 : || !FORWARDER_BLOCK_P (jump_block))
139 : : return false;
140 : 1673893 : jump_dest_block = single_succ (jump_block);
141 : :
142 : : /* If we are partitioning hot/cold basic blocks, we don't want to
143 : : mess up unconditional or indirect jumps that cross between hot
144 : : and cold sections.
145 : :
146 : : Basic block partitioning may result in some jumps that appear to
147 : : be optimizable (or blocks that appear to be mergeable), but which really
148 : : must be left untouched (they are required to make it safely across
149 : : partition boundaries). See the comments at the top of
150 : : bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */
151 : :
152 : 1673893 : if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block)
153 : 1638860 : || (cbranch_jump_edge->flags & EDGE_CROSSING))
154 : : return false;
155 : :
156 : : /* The conditional branch must target the block after the
157 : : unconditional branch. */
158 : 1447166 : cbranch_dest_block = cbranch_jump_edge->dest;
159 : :
160 : 1447166 : if (cbranch_dest_block == EXIT_BLOCK_PTR_FOR_FN (cfun)
161 : 1447166 : || jump_dest_block == EXIT_BLOCK_PTR_FOR_FN (cfun)
162 : 2893627 : || !can_fallthru (jump_block, cbranch_dest_block))
163 : 1439509 : return false;
164 : :
165 : : /* Invert the conditional branch. */
166 : 7657 : if (!invert_jump (as_a <rtx_jump_insn *> (cbranch_insn),
167 : 7657 : block_label (jump_dest_block), 0))
168 : : return false;
169 : :
170 : 7657 : if (dump_file)
171 : 1 : fprintf (dump_file, "Simplifying condjump %i around jump %i\n",
172 : 1 : INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block)));
173 : :
174 : : /* Success. Update the CFG to match. Note that after this point
175 : : the edge variable names appear backwards; the redirection is done
176 : : this way to preserve edge profile data. */
177 : 7657 : cbranch_jump_edge = redirect_edge_succ_nodup (cbranch_jump_edge,
178 : : cbranch_dest_block);
179 : 7657 : cbranch_fallthru_edge = redirect_edge_succ_nodup (cbranch_fallthru_edge,
180 : : jump_dest_block);
181 : 7657 : cbranch_jump_edge->flags |= EDGE_FALLTHRU;
182 : 7657 : cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU;
183 : 7657 : update_br_prob_note (cbranch_block);
184 : :
185 : : /* Delete the block with the unconditional jump, and clean up the mess. */
186 : 7657 : delete_basic_block (jump_block);
187 : 7657 : tidy_fallthru_edge (cbranch_jump_edge);
188 : 7657 : update_forwarder_flag (cbranch_block);
189 : :
190 : 7657 : return true;
191 : : }
192 : :
193 : : /* Attempt to prove that operation is NOOP using CSElib or mark the effect
194 : : on register. Used by jump threading. */
195 : :
196 : : static bool
197 : 27492658 : mark_effect (rtx exp, regset nonequal)
198 : : {
199 : 27492658 : rtx dest;
200 : 27492658 : switch (GET_CODE (exp))
201 : : {
202 : : /* In case we do clobber the register, mark it as equal, as we know the
203 : : value is dead so it don't have to match. */
204 : 2197071 : case CLOBBER:
205 : 2197071 : dest = XEXP (exp, 0);
206 : 2197071 : if (REG_P (dest))
207 : 2164250 : bitmap_clear_range (nonequal, REGNO (dest), REG_NREGS (dest));
208 : : return false;
209 : :
210 : 9962056 : case SET:
211 : 9962056 : if (cselib_redundant_set_p (exp))
212 : : return false;
213 : 9769127 : dest = SET_DEST (exp);
214 : 9769127 : if (dest == pc_rtx)
215 : : return false;
216 : 9761301 : if (!REG_P (dest))
217 : : return true;
218 : 9275469 : bitmap_set_range (nonequal, REGNO (dest), REG_NREGS (dest));
219 : 9275469 : return false;
220 : :
221 : : default:
222 : : return false;
223 : : }
224 : : }
225 : :
226 : : /* Return true if X contains a register in NONEQUAL. */
227 : : static bool
228 : 3170481 : mentions_nonequal_regs (const_rtx x, regset nonequal)
229 : : {
230 : 3170481 : subrtx_iterator::array_type array;
231 : 6357306 : FOR_EACH_SUBRTX (iter, array, x, NONCONST)
232 : : {
233 : 6349480 : const_rtx x = *iter;
234 : 6349480 : if (REG_P (x))
235 : : {
236 : 3170654 : unsigned int end_regno = END_REGNO (x);
237 : 3178653 : for (unsigned int regno = REGNO (x); regno < end_regno; ++regno)
238 : 3170654 : if (REGNO_REG_SET_P (nonequal, regno))
239 : 3162655 : return true;
240 : : }
241 : : }
242 : 7826 : return false;
243 : 3170481 : }
244 : :
245 : : /* Attempt to prove that the basic block B will have no side effects and
246 : : always continues in the same edge if reached via E. Return the edge
247 : : if exist, NULL otherwise. */
248 : :
249 : : static edge
250 : 25988836 : thread_jump (edge e, basic_block b)
251 : : {
252 : 25988836 : rtx set1, set2, cond1, cond2;
253 : 25988836 : rtx_insn *insn;
254 : 25988836 : enum rtx_code code1, code2, reversed_code2;
255 : 25988836 : bool reverse1 = false;
256 : 25988836 : unsigned i;
257 : 25988836 : regset nonequal;
258 : 25988836 : bool failed = false;
259 : :
260 : : /* Jump threading may cause fixup_partitions to introduce new crossing edges,
261 : : which is not allowed after reload. */
262 : 25988836 : gcc_checking_assert (!reload_completed || !crtl->has_bb_partition);
263 : :
264 : 25988836 : if (b->flags & BB_NONTHREADABLE_BLOCK)
265 : : return NULL;
266 : :
267 : : /* At the moment, we do handle only conditional jumps, but later we may
268 : : want to extend this code to tablejumps and others. */
269 : 41652380 : if (EDGE_COUNT (e->src->succs) != 2)
270 : : return NULL;
271 : 15671030 : if (EDGE_COUNT (b->succs) != 2)
272 : : {
273 : 6983557 : b->flags |= BB_NONTHREADABLE_BLOCK;
274 : 6983557 : return NULL;
275 : : }
276 : :
277 : : /* Second branch must end with onlyjump, as we will eliminate the jump. */
278 : 8687473 : if (!any_condjump_p (BB_END (e->src)))
279 : : return NULL;
280 : :
281 : 7858024 : if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b)))
282 : : {
283 : 576897 : b->flags |= BB_NONTHREADABLE_BLOCK;
284 : 576897 : return NULL;
285 : : }
286 : :
287 : 7281127 : set1 = pc_set (BB_END (e->src));
288 : 7281127 : set2 = pc_set (BB_END (b));
289 : 7281127 : if (((e->flags & EDGE_FALLTHRU) != 0)
290 : 7281127 : != (XEXP (SET_SRC (set1), 1) == pc_rtx))
291 : 3651134 : reverse1 = true;
292 : :
293 : 7281127 : cond1 = XEXP (SET_SRC (set1), 0);
294 : 7281127 : cond2 = XEXP (SET_SRC (set2), 0);
295 : 7281127 : if (reverse1)
296 : 3651134 : code1 = reversed_comparison_code (cond1, BB_END (e->src));
297 : : else
298 : 3629993 : code1 = GET_CODE (cond1);
299 : :
300 : 7281127 : code2 = GET_CODE (cond2);
301 : 7281127 : reversed_code2 = reversed_comparison_code (cond2, BB_END (b));
302 : :
303 : 7281127 : if (!comparison_dominates_p (code1, code2)
304 : 7281127 : && !comparison_dominates_p (code1, reversed_code2))
305 : : return NULL;
306 : :
307 : : /* Ensure that the comparison operators are equivalent.
308 : : ??? This is far too pessimistic. We should allow swapped operands,
309 : : different CCmodes, or for example comparisons for interval, that
310 : : dominate even when operands are not equivalent. */
311 : 5845226 : if (!rtx_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
312 : 5845226 : || !rtx_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
313 : 850006 : return NULL;
314 : :
315 : : /* Punt if BB_END (e->src) is doloop-like conditional jump that modifies
316 : : the registers used in cond1. */
317 : 4995220 : if (modified_in_p (cond1, BB_END (e->src)))
318 : : return NULL;
319 : :
320 : : /* Short circuit cases where block B contains some side effects, as we can't
321 : : safely bypass it. */
322 : 53972451 : for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b));
323 : 43982011 : insn = NEXT_INSN (insn))
324 : 45320918 : if (INSN_P (insn) && side_effects_p (PATTERN (insn)))
325 : : {
326 : 1338907 : b->flags |= BB_NONTHREADABLE_BLOCK;
327 : 1338907 : return NULL;
328 : : }
329 : :
330 : 3656313 : cselib_init (0);
331 : :
332 : : /* First process all values computed in the source basic block. */
333 : 49618839 : for (insn = NEXT_INSN (BB_HEAD (e->src));
334 : 49618839 : insn != NEXT_INSN (BB_END (e->src));
335 : 45962526 : insn = NEXT_INSN (insn))
336 : 45962526 : if (INSN_P (insn))
337 : 42662100 : cselib_process_insn (insn);
338 : :
339 : 3656313 : nonequal = BITMAP_ALLOC (NULL);
340 : 3656313 : CLEAR_REG_SET (nonequal);
341 : :
342 : : /* Now assume that we've continued by the edge E to B and continue
343 : : processing as if it were same basic block.
344 : : Our goal is to prove that whole block is an NOOP. */
345 : :
346 : 31590904 : for (insn = NEXT_INSN (BB_HEAD (b));
347 : 31590904 : insn != NEXT_INSN (BB_END (b)) && !failed;
348 : 27934591 : insn = NEXT_INSN (insn))
349 : : {
350 : : /* cond2 must not mention any register that is not equal to the
351 : : former block. Check this before processing that instruction,
352 : : as BB_END (b) could contain also clobbers. */
353 : 31097246 : if (insn == BB_END (b)
354 : 31097246 : && mentions_nonequal_regs (cond2, nonequal))
355 : 3162655 : goto failed_exit;
356 : :
357 : 27934591 : if (INSN_P (insn))
358 : : {
359 : 25205139 : rtx pat = PATTERN (insn);
360 : :
361 : 25205139 : if (GET_CODE (pat) == PARALLEL)
362 : : {
363 : 6676067 : for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++)
364 : 4481793 : failed |= mark_effect (XVECEXP (pat, 0, i), nonequal);
365 : : }
366 : : else
367 : 23010865 : failed |= mark_effect (pat, nonequal);
368 : : }
369 : :
370 : 27934591 : cselib_process_insn (insn);
371 : : }
372 : :
373 : : /* Later we should clear nonequal of dead registers. So far we don't
374 : : have life information in cfg_cleanup. */
375 : 493658 : if (failed)
376 : : {
377 : 485832 : b->flags |= BB_NONTHREADABLE_BLOCK;
378 : 485832 : goto failed_exit;
379 : : }
380 : :
381 : 7826 : if (!REG_SET_EMPTY_P (nonequal))
382 : 340 : goto failed_exit;
383 : :
384 : 7486 : BITMAP_FREE (nonequal);
385 : 7486 : cselib_finish ();
386 : 7486 : if ((comparison_dominates_p (code1, code2) != 0)
387 : 7486 : != (XEXP (SET_SRC (set2), 1) == pc_rtx))
388 : 4747 : return BRANCH_EDGE (b);
389 : : else
390 : 2739 : return FALLTHRU_EDGE (b);
391 : :
392 : 3648827 : failed_exit:
393 : 3648827 : BITMAP_FREE (nonequal);
394 : 3648827 : cselib_finish ();
395 : 3648827 : return NULL;
396 : : }
397 : :
398 : : /* Attempt to forward edges leaving basic block B.
399 : : Return true if successful. */
400 : :
401 : : static bool
402 : 370653011 : try_forward_edges (int mode, basic_block b)
403 : : {
404 : 370653011 : bool changed = false;
405 : 370653011 : edge_iterator ei;
406 : 370653011 : edge e, *threaded_edges = NULL;
407 : :
408 : 928541704 : for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); )
409 : : {
410 : 557888693 : basic_block target, first;
411 : 557888693 : location_t goto_locus;
412 : 557888693 : int counter;
413 : 557888693 : bool threaded = false;
414 : 557888693 : int nthreaded_edges = 0;
415 : 557888693 : bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0;
416 : 557888693 : bool new_target_threaded = false;
417 : :
418 : : /* Skip complex edges because we don't know how to update them.
419 : :
420 : : Still handle fallthru edges, as we can succeed to forward fallthru
421 : : edge to the same place as the branch edge of conditional branch
422 : : and turn conditional branch to an unconditional branch. */
423 : 557888693 : if (e->flags & EDGE_COMPLEX)
424 : : {
425 : 32553672 : ei_next (&ei);
426 : 32553672 : continue;
427 : : }
428 : :
429 : 525335021 : target = first = e->dest;
430 : 525335021 : counter = NUM_FIXED_BLOCKS;
431 : 525335021 : goto_locus = e->goto_locus;
432 : :
433 : 551841075 : while (counter < n_basic_blocks_for_fn (cfun))
434 : : {
435 : 551452251 : basic_block new_target = NULL;
436 : 551452251 : may_thread |= (target->flags & BB_MODIFIED) != 0;
437 : :
438 : 551452251 : if (FORWARDER_BLOCK_P (target)
439 : 586904558 : && single_succ (target) != EXIT_BLOCK_PTR_FOR_FN (cfun))
440 : : {
441 : : /* Bypass trivial infinite loops. */
442 : 26588364 : new_target = single_succ (target);
443 : 26588364 : if (target == new_target)
444 : : counter = n_basic_blocks_for_fn (cfun);
445 : 26323018 : else if (!optimize)
446 : : {
447 : : /* When not optimizing, ensure that edges or forwarder
448 : : blocks with different locus are not optimized out. */
449 : 1094995 : location_t new_locus = single_succ_edge (target)->goto_locus;
450 : 1094995 : location_t locus = goto_locus;
451 : :
452 : 1094995 : if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION
453 : 357587 : && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION
454 : 1307817 : && new_locus != locus)
455 : : new_target = NULL;
456 : : else
457 : : {
458 : 1012928 : if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION)
459 : 275520 : locus = new_locus;
460 : :
461 : 1012928 : rtx_insn *last = BB_END (target);
462 : 1012928 : if (DEBUG_INSN_P (last))
463 : 6 : last = prev_nondebug_insn (last);
464 : 1012928 : if (last && INSN_P (last))
465 : 492699 : new_locus = INSN_LOCATION (last);
466 : : else
467 : : new_locus = UNKNOWN_LOCATION;
468 : :
469 : 492699 : if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION
470 : 410453 : && LOCATION_LOCUS (locus) != UNKNOWN_LOCATION
471 : 1320473 : && new_locus != locus)
472 : : new_target = NULL;
473 : : else
474 : : {
475 : 1005678 : if (LOCATION_LOCUS (new_locus) != UNKNOWN_LOCATION)
476 : 403203 : locus = new_locus;
477 : :
478 : : goto_locus = locus;
479 : : }
480 : : }
481 : : }
482 : : }
483 : :
484 : : /* Allow to thread only over one edge at time to simplify updating
485 : : of probabilities. */
486 : 524863887 : else if ((mode & CLEANUP_THREADING) && may_thread)
487 : : {
488 : 25988836 : edge t = thread_jump (e, target);
489 : 25988836 : if (t)
490 : : {
491 : 7486 : if (!threaded_edges)
492 : 7412 : threaded_edges = XNEWVEC (edge,
493 : : n_basic_blocks_for_fn (cfun));
494 : : else
495 : : {
496 : : int i;
497 : :
498 : : /* Detect an infinite loop across blocks not
499 : : including the start block. */
500 : 165 : for (i = 0; i < nthreaded_edges; ++i)
501 : 116 : if (threaded_edges[i] == t)
502 : : break;
503 : 74 : if (i < nthreaded_edges)
504 : : {
505 : 25 : counter = n_basic_blocks_for_fn (cfun);
506 : 25 : break;
507 : : }
508 : : }
509 : :
510 : : /* Detect an infinite loop across the start block. */
511 : 7461 : if (t->dest == b)
512 : : break;
513 : :
514 : 7007 : gcc_assert (nthreaded_edges
515 : : < (n_basic_blocks_for_fn (cfun)
516 : : - NUM_FIXED_BLOCKS));
517 : 7007 : threaded_edges[nthreaded_edges++] = t;
518 : :
519 : 7007 : new_target = t->dest;
520 : 7007 : new_target_threaded = true;
521 : : }
522 : : }
523 : :
524 : 26506054 : if (!new_target)
525 : : break;
526 : :
527 : 26506054 : counter++;
528 : : /* Do not turn non-crossing jump to crossing. Depending on target
529 : : it may require different instruction pattern. */
530 : 26506054 : if ((e->flags & EDGE_CROSSING)
531 : 26476950 : || BB_PARTITION (first) == BB_PARTITION (new_target))
532 : : {
533 : 15066844 : target = new_target;
534 : 15066844 : threaded |= new_target_threaded;
535 : : }
536 : : }
537 : :
538 : 525335021 : if (counter >= n_basic_blocks_for_fn (cfun))
539 : : {
540 : 388849 : if (dump_file)
541 : 4 : fprintf (dump_file, "Infinite loop in BB %i.\n",
542 : : target->index);
543 : : }
544 : 524946172 : else if (target == first)
545 : : ; /* We didn't do anything. */
546 : : else
547 : : {
548 : : /* Save the values now, as the edge may get removed. */
549 : 13775153 : profile_count edge_count = e->count ();
550 : 13775153 : int n = 0;
551 : :
552 : 13775153 : e->goto_locus = goto_locus;
553 : :
554 : : /* Don't force if target is exit block. */
555 : 13775153 : if (threaded && target != EXIT_BLOCK_PTR_FOR_FN (cfun))
556 : : {
557 : 6948 : notice_new_block (redirect_edge_and_branch_force (e, target));
558 : 6948 : if (dump_file)
559 : 0 : fprintf (dump_file, "Conditionals threaded.\n");
560 : : }
561 : 13768205 : else if (!redirect_edge_and_branch (e, target))
562 : : {
563 : 7476833 : if (dump_file)
564 : 161 : fprintf (dump_file,
565 : : "Forwarding edge %i->%i to %i failed.\n",
566 : 161 : b->index, e->dest->index, target->index);
567 : 7476833 : ei_next (&ei);
568 : 7476833 : continue;
569 : : }
570 : :
571 : : /* We successfully forwarded the edge. Now update profile
572 : : data: for each edge we traversed in the chain, remove
573 : : the original edge's execution count. */
574 : 6473840 : do
575 : : {
576 : 6473840 : edge t;
577 : :
578 : 6473840 : if (!single_succ_p (first))
579 : : {
580 : 6981 : gcc_assert (n < nthreaded_edges);
581 : 6981 : t = threaded_edges [n++];
582 : 6981 : gcc_assert (t->src == first);
583 : 6981 : update_bb_profile_for_threading (first, edge_count, t);
584 : 6981 : update_br_prob_note (first);
585 : : }
586 : : else
587 : : {
588 : 6466859 : first->count -= edge_count;
589 : : /* It is possible that as the result of
590 : : threading we've removed edge as it is
591 : : threaded to the fallthru edge. Avoid
592 : : getting out of sync. */
593 : 6466859 : if (n < nthreaded_edges
594 : 0 : && first == threaded_edges [n]->src)
595 : 0 : n++;
596 : 6466859 : t = single_succ_edge (first);
597 : : }
598 : :
599 : 6473840 : first = t->dest;
600 : : }
601 : 6473840 : while (first != target);
602 : :
603 : 6298320 : changed = true;
604 : 6298320 : continue;
605 : 6298320 : }
606 : 511559868 : ei_next (&ei);
607 : : }
608 : :
609 : 370653011 : free (threaded_edges);
610 : 370653011 : return changed;
611 : : }
612 : :
613 : :
614 : : /* Blocks A and B are to be merged into a single block. A has no incoming
615 : : fallthru edge, so it can be moved before B without adding or modifying
616 : : any jumps (aside from the jump from A to B). */
617 : :
618 : : static void
619 : 22406 : merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b)
620 : : {
621 : 22406 : rtx_insn *barrier;
622 : :
623 : : /* If we are partitioning hot/cold basic blocks, we don't want to
624 : : mess up unconditional or indirect jumps that cross between hot
625 : : and cold sections.
626 : :
627 : : Basic block partitioning may result in some jumps that appear to
628 : : be optimizable (or blocks that appear to be mergeable), but which really
629 : : must be left untouched (they are required to make it safely across
630 : : partition boundaries). See the comments at the top of
631 : : bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */
632 : :
633 : 22406 : if (BB_PARTITION (a) != BB_PARTITION (b))
634 : : return;
635 : :
636 : 22406 : barrier = next_nonnote_insn (BB_END (a));
637 : 22406 : gcc_assert (BARRIER_P (barrier));
638 : 22406 : delete_insn (barrier);
639 : :
640 : : /* Scramble the insn chain. */
641 : 22406 : if (BB_END (a) != PREV_INSN (BB_HEAD (b)))
642 : 22370 : reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b)));
643 : 22406 : df_set_bb_dirty (a);
644 : :
645 : 22406 : if (dump_file)
646 : 0 : fprintf (dump_file, "Moved block %d before %d and merged.\n",
647 : : a->index, b->index);
648 : :
649 : : /* Swap the records for the two blocks around. */
650 : :
651 : 22406 : unlink_block (a);
652 : 22406 : link_block (a, b->prev_bb);
653 : :
654 : : /* Now blocks A and B are contiguous. Merge them. */
655 : 22406 : merge_blocks (a, b);
656 : : }
657 : :
658 : : /* Blocks A and B are to be merged into a single block. B has no outgoing
659 : : fallthru edge, so it can be moved after A without adding or modifying
660 : : any jumps (aside from the jump from A to B). */
661 : :
662 : : static void
663 : 24821 : merge_blocks_move_successor_nojumps (basic_block a, basic_block b)
664 : : {
665 : 24821 : rtx_insn *barrier, *real_b_end;
666 : 24821 : rtx_insn *label;
667 : 24821 : rtx_jump_table_data *table;
668 : :
669 : : /* If we are partitioning hot/cold basic blocks, we don't want to
670 : : mess up unconditional or indirect jumps that cross between hot
671 : : and cold sections.
672 : :
673 : : Basic block partitioning may result in some jumps that appear to
674 : : be optimizable (or blocks that appear to be mergeable), but which really
675 : : must be left untouched (they are required to make it safely across
676 : : partition boundaries). See the comments at the top of
677 : : bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */
678 : :
679 : 24821 : if (BB_PARTITION (a) != BB_PARTITION (b))
680 : 0 : return;
681 : :
682 : 24821 : real_b_end = BB_END (b);
683 : :
684 : : /* If there is a jump table following block B temporarily add the jump table
685 : : to block B so that it will also be moved to the correct location. */
686 : 24821 : if (tablejump_p (BB_END (b), &label, &table)
687 : 24821 : && prev_active_insn (label) == BB_END (b))
688 : : {
689 : 0 : BB_END (b) = table;
690 : : }
691 : :
692 : : /* There had better have been a barrier there. Delete it. */
693 : 24821 : barrier = NEXT_INSN (BB_END (b));
694 : 24821 : if (barrier && BARRIER_P (barrier))
695 : 24821 : delete_insn (barrier);
696 : :
697 : :
698 : : /* Scramble the insn chain. */
699 : 24821 : reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a));
700 : :
701 : : /* Restore the real end of b. */
702 : 24821 : BB_END (b) = real_b_end;
703 : :
704 : 24821 : if (dump_file)
705 : 7 : fprintf (dump_file, "Moved block %d after %d and merged.\n",
706 : : b->index, a->index);
707 : :
708 : : /* Now blocks A and B are contiguous. Merge them. */
709 : 24821 : merge_blocks (a, b);
710 : : }
711 : :
712 : : /* Attempt to merge basic blocks that are potentially non-adjacent.
713 : : Return NULL iff the attempt failed, otherwise return basic block
714 : : where cleanup_cfg should continue. Because the merging commonly
715 : : moves basic block away or introduces another optimization
716 : : possibility, return basic block just before B so cleanup_cfg don't
717 : : need to iterate.
718 : :
719 : : It may be good idea to return basic block before C in the case
720 : : C has been moved after B and originally appeared earlier in the
721 : : insn sequence, but we have no information available about the
722 : : relative ordering of these two. Hopefully it is not too common. */
723 : :
724 : : static basic_block
725 : 6796923 : merge_blocks_move (edge e, basic_block b, basic_block c, int mode)
726 : : {
727 : 6796923 : basic_block next;
728 : :
729 : : /* If we are partitioning hot/cold basic blocks, we don't want to
730 : : mess up unconditional or indirect jumps that cross between hot
731 : : and cold sections.
732 : :
733 : : Basic block partitioning may result in some jumps that appear to
734 : : be optimizable (or blocks that appear to be mergeable), but which really
735 : : must be left untouched (they are required to make it safely across
736 : : partition boundaries). See the comments at the top of
737 : : bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */
738 : :
739 : 6796923 : if (BB_PARTITION (b) != BB_PARTITION (c))
740 : : return NULL;
741 : :
742 : : /* If B has a fallthru edge to C, no need to move anything. */
743 : 6463608 : if (e->flags & EDGE_FALLTHRU)
744 : : {
745 : 3640842 : int b_index = b->index, c_index = c->index;
746 : :
747 : : /* Protect the loop latches. */
748 : 3640842 : if (current_loops && c->loop_father->latch == c)
749 : : return NULL;
750 : :
751 : 3595285 : merge_blocks (b, c);
752 : 3595285 : update_forwarder_flag (b);
753 : :
754 : 3595285 : if (dump_file)
755 : 674 : fprintf (dump_file, "Merged %d and %d without moving.\n",
756 : : b_index, c_index);
757 : :
758 : 4685076 : return b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? b : b->prev_bb;
759 : : }
760 : :
761 : : /* Otherwise we will need to move code around. Do that only if expensive
762 : : transformations are allowed. */
763 : 2822766 : else if (mode & CLEANUP_EXPENSIVE)
764 : : {
765 : 893195 : edge tmp_edge, b_fallthru_edge;
766 : 893195 : bool c_has_outgoing_fallthru;
767 : 893195 : bool b_has_incoming_fallthru;
768 : :
769 : : /* Avoid overactive code motion, as the forwarder blocks should be
770 : : eliminated by edge redirection instead. One exception might have
771 : : been if B is a forwarder block and C has no fallthru edge, but
772 : : that should be cleaned up by bb-reorder instead. */
773 : 893195 : if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c))
774 : : return NULL;
775 : :
776 : : /* We must make sure to not munge nesting of lexical blocks,
777 : : and loop notes. This is done by squeezing out all the notes
778 : : and leaving them there to lie. Not ideal, but functional. */
779 : :
780 : 49362 : tmp_edge = find_fallthru_edge (c->succs);
781 : 49362 : c_has_outgoing_fallthru = (tmp_edge != NULL);
782 : :
783 : 49362 : tmp_edge = find_fallthru_edge (b->preds);
784 : 49362 : b_has_incoming_fallthru = (tmp_edge != NULL);
785 : 49362 : b_fallthru_edge = tmp_edge;
786 : 49362 : next = b->prev_bb;
787 : 49362 : if (next == c)
788 : 39 : next = next->prev_bb;
789 : :
790 : : /* Otherwise, we're going to try to move C after B. If C does
791 : : not have an outgoing fallthru, then it can be moved
792 : : immediately after B without introducing or modifying jumps. */
793 : 49362 : if (! c_has_outgoing_fallthru)
794 : : {
795 : 24821 : merge_blocks_move_successor_nojumps (b, c);
796 : 24821 : return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next;
797 : : }
798 : :
799 : : /* If B does not have an incoming fallthru, then it can be moved
800 : : immediately before C without introducing or modifying jumps.
801 : : C cannot be the first block, so we do not have to worry about
802 : : accessing a non-existent block. */
803 : :
804 : 24541 : if (b_has_incoming_fallthru)
805 : : {
806 : 22826 : basic_block bb;
807 : :
808 : 22826 : if (b_fallthru_edge->src == ENTRY_BLOCK_PTR_FOR_FN (cfun))
809 : : return NULL;
810 : 20691 : bb = force_nonfallthru (b_fallthru_edge);
811 : 20691 : if (bb)
812 : 15724 : notice_new_block (bb);
813 : : }
814 : :
815 : 22406 : merge_blocks_move_predecessor_nojumps (b, c);
816 : 22406 : return next == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? next->next_bb : next;
817 : : }
818 : :
819 : : return NULL;
820 : : }
821 : :
822 : :
823 : : /* Removes the memory attributes of MEM expression
824 : : if they are not equal. */
825 : :
826 : : static void
827 : 125748137 : merge_memattrs (rtx x, rtx y)
828 : : {
829 : 125748137 : int i;
830 : 125748137 : int j;
831 : 125748137 : enum rtx_code code;
832 : 125748137 : const char *fmt;
833 : :
834 : 125748137 : if (x == y)
835 : : return;
836 : 93125738 : if (x == 0 || y == 0)
837 : : return;
838 : :
839 : 93079998 : code = GET_CODE (x);
840 : :
841 : 93079998 : if (code != GET_CODE (y))
842 : : return;
843 : :
844 : 93079943 : if (GET_MODE (x) != GET_MODE (y))
845 : : return;
846 : :
847 : 93077602 : if (code == MEM && !mem_attrs_eq_p (MEM_ATTRS (x), MEM_ATTRS (y)))
848 : : {
849 : 41240 : if (! MEM_ATTRS (x))
850 : 995 : MEM_ATTRS (y) = 0;
851 : 40245 : else if (! MEM_ATTRS (y))
852 : 955 : MEM_ATTRS (x) = 0;
853 : : else
854 : : {
855 : 39290 : if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
856 : : {
857 : 1498 : set_mem_alias_set (x, 0);
858 : 1498 : set_mem_alias_set (y, 0);
859 : : }
860 : :
861 : 39290 : if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y)))
862 : : {
863 : 39125 : set_mem_expr (x, 0);
864 : 39125 : set_mem_expr (y, 0);
865 : 39125 : clear_mem_offset (x);
866 : 39125 : clear_mem_offset (y);
867 : : }
868 : 165 : else if (MEM_OFFSET_KNOWN_P (x) != MEM_OFFSET_KNOWN_P (y)
869 : 165 : || (MEM_OFFSET_KNOWN_P (x)
870 : 0 : && maybe_ne (MEM_OFFSET (x), MEM_OFFSET (y))))
871 : : {
872 : 0 : clear_mem_offset (x);
873 : 0 : clear_mem_offset (y);
874 : : }
875 : :
876 : 44295 : if (!MEM_SIZE_KNOWN_P (x))
877 : 215 : clear_mem_size (y);
878 : 43876 : else if (!MEM_SIZE_KNOWN_P (y))
879 : 0 : clear_mem_size (x);
880 : 39075 : else if (known_le (MEM_SIZE (x), MEM_SIZE (y)))
881 : 39048 : set_mem_size (x, MEM_SIZE (y));
882 : 27 : else if (known_le (MEM_SIZE (y), MEM_SIZE (x)))
883 : 27 : set_mem_size (y, MEM_SIZE (x));
884 : : else
885 : : {
886 : : /* The sizes aren't ordered, so we can't merge them. */
887 : : clear_mem_size (x);
888 : : clear_mem_size (y);
889 : : }
890 : :
891 : 49305 : set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y)));
892 : 44313 : set_mem_align (y, MEM_ALIGN (x));
893 : : }
894 : : }
895 : 93077602 : if (code == MEM)
896 : : {
897 : 4873112 : if (MEM_READONLY_P (x) != MEM_READONLY_P (y))
898 : : {
899 : 0 : MEM_READONLY_P (x) = 0;
900 : 0 : MEM_READONLY_P (y) = 0;
901 : : }
902 : 4873112 : if (MEM_NOTRAP_P (x) != MEM_NOTRAP_P (y))
903 : : {
904 : 106 : MEM_NOTRAP_P (x) = 0;
905 : 106 : MEM_NOTRAP_P (y) = 0;
906 : : }
907 : 4873112 : if (MEM_VOLATILE_P (x) != MEM_VOLATILE_P (y))
908 : : {
909 : 6 : MEM_VOLATILE_P (x) = 1;
910 : 6 : MEM_VOLATILE_P (y) = 1;
911 : : }
912 : : }
913 : :
914 : 93077602 : fmt = GET_RTX_FORMAT (code);
915 : 279044209 : for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
916 : : {
917 : 185966607 : switch (fmt[i])
918 : : {
919 : 311993 : case 'E':
920 : : /* Two vectors must have the same length. */
921 : 311993 : if (XVECLEN (x, i) != XVECLEN (y, i))
922 : : return;
923 : :
924 : 928457 : for (j = 0; j < XVECLEN (x, i); j++)
925 : 616464 : merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j));
926 : :
927 : : break;
928 : :
929 : 118019629 : case 'e':
930 : 118019629 : merge_memattrs (XEXP (x, i), XEXP (y, i));
931 : : }
932 : : }
933 : : return;
934 : : }
935 : :
936 : :
937 : : /* Checks if patterns P1 and P2 are equivalent, apart from the possibly
938 : : different single sets S1 and S2. */
939 : :
940 : : static bool
941 : 8 : equal_different_set_p (rtx p1, rtx s1, rtx p2, rtx s2)
942 : : {
943 : 8 : int i;
944 : 8 : rtx e1, e2;
945 : :
946 : 8 : if (p1 == s1 && p2 == s2)
947 : : return true;
948 : :
949 : 4 : if (GET_CODE (p1) != PARALLEL || GET_CODE (p2) != PARALLEL)
950 : : return false;
951 : :
952 : 4 : if (XVECLEN (p1, 0) != XVECLEN (p2, 0))
953 : : return false;
954 : :
955 : 8 : for (i = 0; i < XVECLEN (p1, 0); i++)
956 : : {
957 : 8 : e1 = XVECEXP (p1, 0, i);
958 : 8 : e2 = XVECEXP (p2, 0, i);
959 : 8 : if (e1 == s1 && e2 == s2)
960 : 0 : continue;
961 : 8 : if (reload_completed
962 : 8 : ? rtx_renumbered_equal_p (e1, e2) : rtx_equal_p (e1, e2))
963 : 4 : continue;
964 : :
965 : : return false;
966 : : }
967 : :
968 : : return true;
969 : : }
970 : :
971 : :
972 : : /* NOTE1 is the REG_EQUAL note, if any, attached to an insn
973 : : that is a single_set with a SET_SRC of SRC1. Similarly
974 : : for NOTE2/SRC2.
975 : :
976 : : So effectively NOTE1/NOTE2 are an alternate form of
977 : : SRC1/SRC2 respectively.
978 : :
979 : : Return nonzero if SRC1 or NOTE1 has the same constant
980 : : integer value as SRC2 or NOTE2. Else return zero. */
981 : : static int
982 : 6021298 : values_equal_p (rtx note1, rtx note2, rtx src1, rtx src2)
983 : : {
984 : 6021298 : if (note1
985 : 6021298 : && note2
986 : 236729 : && CONST_INT_P (XEXP (note1, 0))
987 : 6075457 : && rtx_equal_p (XEXP (note1, 0), XEXP (note2, 0)))
988 : : return 1;
989 : :
990 : 6021298 : if (!note1
991 : 6021298 : && !note2
992 : 5357055 : && CONST_INT_P (src1)
993 : 1954101 : && CONST_INT_P (src2)
994 : 7882321 : && rtx_equal_p (src1, src2))
995 : : return 1;
996 : :
997 : 6021294 : if (note1
998 : 505276 : && CONST_INT_P (src2)
999 : 6173468 : && rtx_equal_p (XEXP (note1, 0), src2))
1000 : : return 1;
1001 : :
1002 : 6021292 : if (note2
1003 : 395696 : && CONST_INT_P (src1)
1004 : 6087231 : && rtx_equal_p (XEXP (note2, 0), src1))
1005 : : return 1;
1006 : :
1007 : : return 0;
1008 : : }
1009 : :
1010 : : /* Examine register notes on I1 and I2 and return:
1011 : : - dir_forward if I1 can be replaced by I2, or
1012 : : - dir_backward if I2 can be replaced by I1, or
1013 : : - dir_both if both are the case. */
1014 : :
1015 : : static enum replace_direction
1016 : 11380456 : can_replace_by (rtx_insn *i1, rtx_insn *i2)
1017 : : {
1018 : 11380456 : rtx s1, s2, d1, d2, src1, src2, note1, note2;
1019 : 11380456 : bool c1, c2;
1020 : :
1021 : : /* Check for 2 sets. */
1022 : 11380456 : s1 = single_set (i1);
1023 : 11380456 : s2 = single_set (i2);
1024 : 11380456 : if (s1 == NULL_RTX || s2 == NULL_RTX)
1025 : : return dir_none;
1026 : :
1027 : : /* Check that the 2 sets set the same dest. */
1028 : 10626556 : d1 = SET_DEST (s1);
1029 : 10626556 : d2 = SET_DEST (s2);
1030 : 21253112 : if (!(reload_completed
1031 : 10626556 : ? rtx_renumbered_equal_p (d1, d2) : rtx_equal_p (d1, d2)))
1032 : : return dir_none;
1033 : :
1034 : : /* Find identical req_equiv or reg_equal note, which implies that the 2 sets
1035 : : set dest to the same value. */
1036 : 6021298 : note1 = find_reg_equal_equiv_note (i1);
1037 : 6021298 : note2 = find_reg_equal_equiv_note (i2);
1038 : :
1039 : 6021298 : src1 = SET_SRC (s1);
1040 : 6021298 : src2 = SET_SRC (s2);
1041 : :
1042 : 6021298 : if (!values_equal_p (note1, note2, src1, src2))
1043 : : return dir_none;
1044 : :
1045 : 8 : if (!equal_different_set_p (PATTERN (i1), s1, PATTERN (i2), s2))
1046 : : return dir_none;
1047 : :
1048 : : /* Although the 2 sets set dest to the same value, we cannot replace
1049 : : (set (dest) (const_int))
1050 : : by
1051 : : (set (dest) (reg))
1052 : : because we don't know if the reg is live and has the same value at the
1053 : : location of replacement. */
1054 : 4 : c1 = CONST_INT_P (src1);
1055 : 4 : c2 = CONST_INT_P (src2);
1056 : 4 : if (c1 && c2)
1057 : : return dir_both;
1058 : 4 : else if (c2)
1059 : : return dir_forward;
1060 : 2 : else if (c1)
1061 : : return dir_backward;
1062 : :
1063 : : return dir_none;
1064 : : }
1065 : :
1066 : : /* Merges directions A and B. */
1067 : :
1068 : : static enum replace_direction
1069 : 19640539 : merge_dir (enum replace_direction a, enum replace_direction b)
1070 : : {
1071 : : /* Implements the following table:
1072 : : |bo fw bw no
1073 : : ---+-----------
1074 : : bo |bo fw bw no
1075 : : fw |-- fw no no
1076 : : bw |-- -- bw no
1077 : : no |-- -- -- no. */
1078 : :
1079 : 0 : if (a == b)
1080 : : return a;
1081 : :
1082 : 13654372 : if (a == dir_both)
1083 : : return b;
1084 : 3217759 : if (b == dir_both)
1085 : 0 : return a;
1086 : :
1087 : : return dir_none;
1088 : : }
1089 : :
1090 : : /* Array of flags indexed by reg note kind, true if the given
1091 : : reg note is CFA related. */
1092 : : static const bool reg_note_cfa_p[] = {
1093 : : #undef REG_CFA_NOTE
1094 : : #define DEF_REG_NOTE(NAME) false,
1095 : : #define REG_CFA_NOTE(NAME) true,
1096 : : #include "reg-notes.def"
1097 : : #undef REG_CFA_NOTE
1098 : : #undef DEF_REG_NOTE
1099 : : false
1100 : : };
1101 : :
1102 : : /* Return true if I1 and I2 have identical CFA notes (the same order
1103 : : and equivalent content). */
1104 : :
1105 : : static bool
1106 : 17424 : insns_have_identical_cfa_notes (rtx_insn *i1, rtx_insn *i2)
1107 : : {
1108 : 17424 : rtx n1, n2;
1109 : 17424 : for (n1 = REG_NOTES (i1), n2 = REG_NOTES (i2); ;
1110 : 19541 : n1 = XEXP (n1, 1), n2 = XEXP (n2, 1))
1111 : : {
1112 : : /* Skip over reg notes not related to CFI information. */
1113 : 61725 : while (n1 && !reg_note_cfa_p[REG_NOTE_KIND (n1)])
1114 : 5219 : n1 = XEXP (n1, 1);
1115 : 42184 : while (n2 && !reg_note_cfa_p[REG_NOTE_KIND (n2)])
1116 : 5219 : n2 = XEXP (n2, 1);
1117 : 36965 : if (n1 == NULL_RTX && n2 == NULL_RTX)
1118 : : return true;
1119 : 19541 : if (n1 == NULL_RTX || n2 == NULL_RTX)
1120 : : return false;
1121 : 19541 : if (XEXP (n1, 0) == XEXP (n2, 0))
1122 : : ;
1123 : 19539 : else if (XEXP (n1, 0) == NULL_RTX || XEXP (n2, 0) == NULL_RTX)
1124 : : return false;
1125 : 39078 : else if (!(reload_completed
1126 : 19539 : ? rtx_renumbered_equal_p (XEXP (n1, 0), XEXP (n2, 0))
1127 : 0 : : rtx_equal_p (XEXP (n1, 0), XEXP (n2, 0))))
1128 : : return false;
1129 : : }
1130 : : }
1131 : :
1132 : : /* Examine I1 and I2 and return:
1133 : : - dir_forward if I1 can be replaced by I2, or
1134 : : - dir_backward if I2 can be replaced by I1, or
1135 : : - dir_both if both are the case. */
1136 : :
1137 : : static enum replace_direction
1138 : 34682189 : old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx_insn *i1, rtx_insn *i2)
1139 : : {
1140 : 34682189 : rtx p1, p2;
1141 : :
1142 : : /* Verify that I1 and I2 are equivalent. */
1143 : 34682189 : if (GET_CODE (i1) != GET_CODE (i2))
1144 : : return dir_none;
1145 : :
1146 : : /* __builtin_unreachable() may lead to empty blocks (ending with
1147 : : NOTE_INSN_BASIC_BLOCK). They may be crossjumped. */
1148 : 29123972 : if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2))
1149 : : return dir_both;
1150 : :
1151 : : /* ??? Do not allow cross-jumping between different stack levels. */
1152 : 29093256 : p1 = find_reg_note (i1, REG_ARGS_SIZE, NULL);
1153 : 29093256 : p2 = find_reg_note (i2, REG_ARGS_SIZE, NULL);
1154 : 29093256 : if (p1 && p2)
1155 : : {
1156 : 3702968 : p1 = XEXP (p1, 0);
1157 : 3702968 : p2 = XEXP (p2, 0);
1158 : 3702968 : if (!rtx_equal_p (p1, p2))
1159 : : return dir_none;
1160 : :
1161 : : /* ??? Worse, this adjustment had better be constant lest we
1162 : : have differing incoming stack levels. */
1163 : 3596803 : if (!frame_pointer_needed
1164 : 3596803 : && known_eq (find_args_size_adjust (i1), HOST_WIDE_INT_MIN))
1165 : 22 : return dir_none;
1166 : : }
1167 : 25390288 : else if (p1 || p2)
1168 : : return dir_none;
1169 : :
1170 : : /* Do not allow cross-jumping between frame related insns and other
1171 : : insns. */
1172 : 27278627 : if (RTX_FRAME_RELATED_P (i1) != RTX_FRAME_RELATED_P (i2))
1173 : : return dir_none;
1174 : :
1175 : 27214099 : p1 = PATTERN (i1);
1176 : 27214099 : p2 = PATTERN (i2);
1177 : :
1178 : 27214099 : if (GET_CODE (p1) != GET_CODE (p2))
1179 : : return dir_none;
1180 : :
1181 : : /* If this is a CALL_INSN, compare register usage information.
1182 : : If we don't check this on stack register machines, the two
1183 : : CALL_INSNs might be merged leaving reg-stack.cc with mismatching
1184 : : numbers of stack registers in the same basic block.
1185 : : If we don't check this on machines with delay slots, a delay slot may
1186 : : be filled that clobbers a parameter expected by the subroutine.
1187 : :
1188 : : ??? We take the simple route for now and assume that if they're
1189 : : equal, they were constructed identically.
1190 : :
1191 : : Also check for identical exception regions. */
1192 : :
1193 : 24864616 : if (CALL_P (i1))
1194 : : {
1195 : : /* Ensure the same EH region. */
1196 : 10723932 : rtx n1 = find_reg_note (i1, REG_EH_REGION, 0);
1197 : 10723932 : rtx n2 = find_reg_note (i2, REG_EH_REGION, 0);
1198 : :
1199 : 10723932 : if (!n1 && n2)
1200 : : return dir_none;
1201 : :
1202 : 10672499 : if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0)))
1203 : : return dir_none;
1204 : :
1205 : 10232409 : if (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1206 : 10232409 : CALL_INSN_FUNCTION_USAGE (i2))
1207 : 10232409 : || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2))
1208 : : return dir_none;
1209 : :
1210 : : /* For address sanitizer, never crossjump __asan_report_* builtins,
1211 : : otherwise errors might be reported on incorrect lines. */
1212 : 6639653 : if (flag_sanitize & SANITIZE_ADDRESS)
1213 : : {
1214 : 233021 : rtx call = get_call_rtx_from (i1);
1215 : 233021 : if (call && GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF)
1216 : : {
1217 : 233021 : rtx symbol = XEXP (XEXP (call, 0), 0);
1218 : 233021 : if (SYMBOL_REF_DECL (symbol)
1219 : 233021 : && TREE_CODE (SYMBOL_REF_DECL (symbol)) == FUNCTION_DECL)
1220 : : {
1221 : 233021 : if ((DECL_BUILT_IN_CLASS (SYMBOL_REF_DECL (symbol))
1222 : 233021 : == BUILT_IN_NORMAL)
1223 : 231372 : && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol))
1224 : : >= BUILT_IN_ASAN_REPORT_LOAD1
1225 : 462786 : && DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol))
1226 : : <= BUILT_IN_ASAN_STOREN)
1227 : : return dir_none;
1228 : : }
1229 : : }
1230 : : }
1231 : :
1232 : 6410849 : if (insn_callee_abi (i1) != insn_callee_abi (i2))
1233 : : return dir_none;
1234 : : }
1235 : :
1236 : : /* If both i1 and i2 are frame related, verify all the CFA notes
1237 : : in the same order and with the same content. */
1238 : 20494103 : if (RTX_FRAME_RELATED_P (i1) && !insns_have_identical_cfa_notes (i1, i2))
1239 : : return dir_none;
1240 : :
1241 : : #ifdef STACK_REGS
1242 : : /* If cross_jump_death_matters is not 0, the insn's mode
1243 : : indicates whether or not the insn contains any stack-like
1244 : : regs. */
1245 : :
1246 : 20494103 : if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1))
1247 : : {
1248 : : /* If register stack conversion has already been done, then
1249 : : death notes must also be compared before it is certain that
1250 : : the two instruction streams match. */
1251 : :
1252 : : rtx note;
1253 : : HARD_REG_SET i1_regset, i2_regset;
1254 : :
1255 : 0 : CLEAR_HARD_REG_SET (i1_regset);
1256 : 0 : CLEAR_HARD_REG_SET (i2_regset);
1257 : :
1258 : 0 : for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1259 : 0 : if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
1260 : 0 : SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1261 : :
1262 : 0 : for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1263 : 0 : if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
1264 : 0 : SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1265 : :
1266 : 0 : if (i1_regset != i2_regset)
1267 : 0 : return dir_none;
1268 : : }
1269 : : #endif
1270 : :
1271 : 20494103 : if (reload_completed
1272 : 20494103 : ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2))
1273 : : return dir_both;
1274 : :
1275 : 11380456 : return can_replace_by (i1, i2);
1276 : : }
1277 : :
1278 : : /* When comparing insns I1 and I2 in flow_find_cross_jump or
1279 : : flow_find_head_matching_sequence, ensure the notes match. */
1280 : :
1281 : : static void
1282 : 7112044 : merge_notes (rtx_insn *i1, rtx_insn *i2)
1283 : : {
1284 : : /* If the merged insns have different REG_EQUAL notes, then
1285 : : remove them. */
1286 : 7112044 : rtx equiv1 = find_reg_equal_equiv_note (i1);
1287 : 7112044 : rtx equiv2 = find_reg_equal_equiv_note (i2);
1288 : :
1289 : 7112044 : if (equiv1 && !equiv2)
1290 : 32951 : remove_note (i1, equiv1);
1291 : 7079093 : else if (!equiv1 && equiv2)
1292 : 5033 : remove_note (i2, equiv2);
1293 : 7074060 : else if (equiv1 && equiv2
1294 : 7074060 : && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1295 : : {
1296 : 462 : remove_note (i1, equiv1);
1297 : 462 : remove_note (i2, equiv2);
1298 : : }
1299 : 7112044 : }
1300 : :
1301 : : /* Walks from I1 in BB1 backward till the next non-debug insn, and returns the
1302 : : resulting insn in I1, and the corresponding bb in BB1. At the head of a
1303 : : bb, if there is a predecessor bb that reaches this bb via fallthru, and
1304 : : FOLLOW_FALLTHRU, walks further in the predecessor bb and registers this in
1305 : : DID_FALLTHRU. Otherwise, stops at the head of the bb. */
1306 : :
1307 : : static void
1308 : 40664202 : walk_to_nondebug_insn (rtx_insn **i1, basic_block *bb1, bool follow_fallthru,
1309 : : bool *did_fallthru)
1310 : : {
1311 : 40664202 : edge fallthru;
1312 : :
1313 : 40664202 : *did_fallthru = false;
1314 : :
1315 : : /* Ignore notes. */
1316 : 59115436 : while (!NONDEBUG_INSN_P (*i1))
1317 : : {
1318 : 19512720 : if (*i1 != BB_HEAD (*bb1))
1319 : : {
1320 : 18283733 : *i1 = PREV_INSN (*i1);
1321 : 18283733 : continue;
1322 : : }
1323 : :
1324 : 1228987 : if (!follow_fallthru)
1325 : : return;
1326 : :
1327 : 1070584 : fallthru = find_fallthru_edge ((*bb1)->preds);
1328 : 503233 : if (!fallthru || fallthru->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)
1329 : 1573762 : || !single_succ_p (fallthru->src))
1330 : : return;
1331 : :
1332 : 167501 : *bb1 = fallthru->src;
1333 : 167501 : *i1 = BB_END (*bb1);
1334 : 167501 : *did_fallthru = true;
1335 : : }
1336 : : }
1337 : :
1338 : : /* Look through the insns at the end of BB1 and BB2 and find the longest
1339 : : sequence that are either equivalent, or allow forward or backward
1340 : : replacement. Store the first insns for that sequence in *F1 and *F2 and
1341 : : return the sequence length.
1342 : :
1343 : : DIR_P indicates the allowed replacement direction on function entry, and
1344 : : the actual replacement direction on function exit. If NULL, only equivalent
1345 : : sequences are allowed.
1346 : :
1347 : : To simplify callers of this function, if the blocks match exactly,
1348 : : store the head of the blocks in *F1 and *F2. */
1349 : :
1350 : : int
1351 : 13405782 : flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx_insn **f1,
1352 : : rtx_insn **f2, enum replace_direction *dir_p)
1353 : : {
1354 : 13405782 : rtx_insn *i1, *i2, *last1, *last2, *afterlast1, *afterlast2;
1355 : 13405782 : int ninsns = 0;
1356 : 13405782 : enum replace_direction dir, last_dir, afterlast_dir;
1357 : 13405782 : bool follow_fallthru, did_fallthru;
1358 : :
1359 : 13405782 : if (dir_p)
1360 : 13405782 : dir = *dir_p;
1361 : : else
1362 : : dir = dir_both;
1363 : 13405782 : afterlast_dir = dir;
1364 : 13405782 : last_dir = afterlast_dir;
1365 : :
1366 : : /* Skip simple jumps at the end of the blocks. Complex jumps still
1367 : : need to be compared for equivalence, which we'll do below. */
1368 : :
1369 : 13405782 : i1 = BB_END (bb1);
1370 : 13405782 : last1 = afterlast1 = last2 = afterlast2 = NULL;
1371 : 13405782 : if (onlyjump_p (i1)
1372 : 13405782 : || (returnjump_p (i1) && !side_effects_p (PATTERN (i1))))
1373 : : {
1374 : 12047743 : last1 = i1;
1375 : 12047743 : i1 = PREV_INSN (i1);
1376 : : }
1377 : :
1378 : 13405782 : i2 = BB_END (bb2);
1379 : 13405782 : if (onlyjump_p (i2)
1380 : 13405782 : || (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
1381 : : {
1382 : 9771692 : last2 = i2;
1383 : : /* Count everything except for unconditional jump as insn.
1384 : : Don't count any jumps if dir_p is NULL. */
1385 : 9771692 : if (!simplejump_p (i2) && !returnjump_p (i2) && last1 && dir_p)
1386 : : ninsns++;
1387 : 9771692 : i2 = PREV_INSN (i2);
1388 : : }
1389 : :
1390 : 27258420 : while (true)
1391 : : {
1392 : : /* In the following example, we can replace all jumps to C by jumps to A.
1393 : :
1394 : : This removes 4 duplicate insns.
1395 : : [bb A] insn1 [bb C] insn1
1396 : : insn2 insn2
1397 : : [bb B] insn3 insn3
1398 : : insn4 insn4
1399 : : jump_insn jump_insn
1400 : :
1401 : : We could also replace all jumps to A by jumps to C, but that leaves B
1402 : : alive, and removes only 2 duplicate insns. In a subsequent crossjump
1403 : : step, all jumps to B would be replaced with jumps to the middle of C,
1404 : : achieving the same result with more effort.
1405 : : So we allow only the first possibility, which means that we don't allow
1406 : : fallthru in the block that's being replaced. */
1407 : :
1408 : 20332101 : follow_fallthru = dir_p && dir != dir_forward;
1409 : 20332101 : walk_to_nondebug_insn (&i1, &bb1, follow_fallthru, &did_fallthru);
1410 : 20332101 : if (did_fallthru)
1411 : 23866 : dir = dir_backward;
1412 : :
1413 : 20332101 : follow_fallthru = dir_p && dir != dir_backward;
1414 : 20332101 : walk_to_nondebug_insn (&i2, &bb2, follow_fallthru, &did_fallthru);
1415 : 20332101 : if (did_fallthru)
1416 : 143635 : dir = dir_forward;
1417 : :
1418 : 20332101 : if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
1419 : : break;
1420 : :
1421 : : /* Do not turn corssing edge to non-crossing or vice versa after
1422 : : reload. */
1423 : 19640539 : if (BB_PARTITION (BLOCK_FOR_INSN (i1))
1424 : 19640539 : != BB_PARTITION (BLOCK_FOR_INSN (i2))
1425 : 19640539 : && reload_completed)
1426 : : break;
1427 : :
1428 : 19640539 : dir = merge_dir (dir, old_insns_match_p (0, i1, i2));
1429 : 17362930 : if (dir == dir_none || (!dir_p && dir != dir_both))
1430 : : break;
1431 : :
1432 : 6926319 : merge_memattrs (i1, i2);
1433 : :
1434 : : /* Don't begin a cross-jump with a NOTE insn. */
1435 : 6926319 : if (INSN_P (i1))
1436 : : {
1437 : 6926319 : merge_notes (i1, i2);
1438 : :
1439 : 6926319 : afterlast1 = last1, afterlast2 = last2;
1440 : 6926319 : last1 = i1, last2 = i2;
1441 : 6926319 : afterlast_dir = last_dir;
1442 : 6926319 : last_dir = dir;
1443 : 6926319 : if (active_insn_p (i1))
1444 : 6835948 : ninsns++;
1445 : : }
1446 : :
1447 : 6926319 : i1 = PREV_INSN (i1);
1448 : 6926319 : i2 = PREV_INSN (i2);
1449 : : }
1450 : :
1451 : : /* Include preceding notes and labels in the cross-jump. One,
1452 : : this may bring us to the head of the blocks as requested above.
1453 : : Two, it keeps line number notes as matched as may be. */
1454 : 13405782 : if (ninsns)
1455 : : {
1456 : 4472462 : bb1 = BLOCK_FOR_INSN (last1);
1457 : 11291851 : while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1)))
1458 : : last1 = PREV_INSN (last1);
1459 : :
1460 : 8654873 : if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
1461 : : last1 = PREV_INSN (last1);
1462 : :
1463 : 4472462 : bb2 = BLOCK_FOR_INSN (last2);
1464 : 11291950 : while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2)))
1465 : : last2 = PREV_INSN (last2);
1466 : :
1467 : 8463985 : if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
1468 : : last2 = PREV_INSN (last2);
1469 : :
1470 : 4472462 : *f1 = last1;
1471 : 4472462 : *f2 = last2;
1472 : : }
1473 : :
1474 : 13405782 : if (dir_p)
1475 : 13405782 : *dir_p = last_dir;
1476 : 13405782 : return ninsns;
1477 : : }
1478 : :
1479 : : /* Like flow_find_cross_jump, except start looking for a matching sequence from
1480 : : the head of the two blocks. Do not include jumps at the end.
1481 : : If STOP_AFTER is nonzero, stop after finding that many matching
1482 : : instructions. If STOP_AFTER is zero, count all INSN_P insns, if it is
1483 : : non-zero, only count active insns. */
1484 : :
1485 : : int
1486 : 4024175 : flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx_insn **f1,
1487 : : rtx_insn **f2, int stop_after)
1488 : : {
1489 : 4024175 : rtx_insn *i1, *i2, *last1, *last2, *beforelast1, *beforelast2;
1490 : 4024175 : int ninsns = 0;
1491 : 4024175 : edge e;
1492 : 4024175 : edge_iterator ei;
1493 : 4024175 : int nehedges1 = 0, nehedges2 = 0;
1494 : :
1495 : 9502462 : FOR_EACH_EDGE (e, ei, bb1->succs)
1496 : 5478287 : if (e->flags & EDGE_EH)
1497 : 302406 : nehedges1++;
1498 : 10007784 : FOR_EACH_EDGE (e, ei, bb2->succs)
1499 : 5983609 : if (e->flags & EDGE_EH)
1500 : 319420 : nehedges2++;
1501 : :
1502 : 4024175 : i1 = BB_HEAD (bb1);
1503 : 4024175 : i2 = BB_HEAD (bb2);
1504 : 4024175 : last1 = beforelast1 = last2 = beforelast2 = NULL;
1505 : :
1506 : 171163 : while (true)
1507 : : {
1508 : : /* Ignore notes, except NOTE_INSN_EPILOGUE_BEG. */
1509 : 16940159 : while (!NONDEBUG_INSN_P (i1) && i1 != BB_END (bb1))
1510 : : {
1511 : 12588660 : if (NOTE_P (i1) && NOTE_KIND (i1) == NOTE_INSN_EPILOGUE_BEG)
1512 : : break;
1513 : 12573658 : i1 = NEXT_INSN (i1);
1514 : : }
1515 : :
1516 : 19059072 : while (!NONDEBUG_INSN_P (i2) && i2 != BB_END (bb2))
1517 : : {
1518 : 14903708 : if (NOTE_P (i2) && NOTE_KIND (i2) == NOTE_INSN_EPILOGUE_BEG)
1519 : : break;
1520 : 14863734 : i2 = NEXT_INSN (i2);
1521 : : }
1522 : :
1523 : 4195338 : if ((i1 == BB_END (bb1) && !NONDEBUG_INSN_P (i1))
1524 : 4182659 : || (i2 == BB_END (bb2) && !NONDEBUG_INSN_P (i2)))
1525 : : break;
1526 : :
1527 : 4177257 : if (NOTE_P (i1) || NOTE_P (i2)
1528 : 4123883 : || JUMP_P (i1) || JUMP_P (i2))
1529 : : break;
1530 : :
1531 : : /* A sanity check to make sure we're not merging insns with different
1532 : : effects on EH. If only one of them ends a basic block, it shouldn't
1533 : : have an EH edge; if both end a basic block, there should be the same
1534 : : number of EH edges. */
1535 : 3295320 : if ((i1 == BB_END (bb1) && i2 != BB_END (bb2)
1536 : 206841 : && nehedges1 > 0)
1537 : 3258045 : || (i2 == BB_END (bb2) && i1 != BB_END (bb1)
1538 : 195533 : && nehedges2 > 0)
1539 : 3233320 : || (i1 == BB_END (bb1) && i2 == BB_END (bb2)
1540 : 24390 : && nehedges1 != nehedges2))
1541 : : break;
1542 : :
1543 : 3230190 : if (old_insns_match_p (0, i1, i2) != dir_both)
1544 : : break;
1545 : :
1546 : 185725 : merge_memattrs (i1, i2);
1547 : :
1548 : : /* Don't begin a cross-jump with a NOTE insn. */
1549 : 185725 : if (INSN_P (i1))
1550 : : {
1551 : 185725 : merge_notes (i1, i2);
1552 : :
1553 : 185725 : beforelast1 = last1, beforelast2 = last2;
1554 : 185725 : last1 = i1, last2 = i2;
1555 : 185725 : if (!stop_after || active_insn_p (i1))
1556 : 185725 : ninsns++;
1557 : : }
1558 : :
1559 : 185725 : if (i1 == BB_END (bb1) || i2 == BB_END (bb2)
1560 : 171163 : || (stop_after > 0 && ninsns == stop_after))
1561 : : break;
1562 : :
1563 : 171163 : i1 = NEXT_INSN (i1);
1564 : 171163 : i2 = NEXT_INSN (i2);
1565 : : }
1566 : :
1567 : 4024175 : if (ninsns)
1568 : : {
1569 : 97380 : *f1 = last1;
1570 : 97380 : *f2 = last2;
1571 : : }
1572 : :
1573 : 4024175 : return ninsns;
1574 : : }
1575 : :
1576 : : /* Return true iff outgoing edges of BB1 and BB2 match, together with
1577 : : the branch instruction. This means that if we commonize the control
1578 : : flow before end of the basic block, the semantic remains unchanged.
1579 : :
1580 : : We may assume that there exists one edge with a common destination. */
1581 : :
1582 : : static bool
1583 : 40945552 : outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
1584 : : {
1585 : 40945552 : int nehedges1 = 0, nehedges2 = 0;
1586 : 40945552 : edge fallthru1 = 0, fallthru2 = 0;
1587 : 40945552 : edge e1, e2;
1588 : 40945552 : edge_iterator ei;
1589 : :
1590 : : /* If we performed shrink-wrapping, edges to the exit block can
1591 : : only be distinguished for JUMP_INSNs. The two paths may differ in
1592 : : whether they went through the prologue. Sibcalls are fine, we know
1593 : : that we either didn't need or inserted an epilogue before them. */
1594 : 40945552 : if (crtl->shrink_wrapped
1595 : 917428 : && single_succ_p (bb1)
1596 : 347595 : && single_succ (bb1) == EXIT_BLOCK_PTR_FOR_FN (cfun)
1597 : 125075 : && (!JUMP_P (BB_END (bb1))
1598 : : /* Punt if the only successor is a fake edge to exit, the jump
1599 : : must be some weird one. */
1600 : 56399 : || (single_succ_edge (bb1)->flags & EDGE_FAKE) != 0)
1601 : 41014308 : && !(CALL_P (BB_END (bb1)) && SIBLING_CALL_P (BB_END (bb1))))
1602 : : return false;
1603 : :
1604 : : /* If BB1 has only one successor, we may be looking at either an
1605 : : unconditional jump, or a fake edge to exit. */
1606 : 40898078 : if (single_succ_p (bb1)
1607 : 16526786 : && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
1608 : 54176987 : && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1))))
1609 : 13042022 : return (single_succ_p (bb2)
1610 : 11733420 : && (single_succ_edge (bb2)->flags
1611 : 11733420 : & (EDGE_COMPLEX | EDGE_FAKE)) == 0
1612 : 24710382 : && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2))));
1613 : :
1614 : : /* Match conditional jumps - this may get tricky when fallthru and branch
1615 : : edges are crossed. */
1616 : 27856056 : if (EDGE_COUNT (bb1->succs) == 2
1617 : 24272519 : && any_condjump_p (BB_END (bb1))
1618 : 43899735 : && onlyjump_p (BB_END (bb1)))
1619 : : {
1620 : 16043679 : edge b1, f1, b2, f2;
1621 : 16043679 : bool reverse, match;
1622 : 16043679 : rtx set1, set2, cond1, cond2;
1623 : 16043679 : enum rtx_code code1, code2;
1624 : :
1625 : 16043679 : if (EDGE_COUNT (bb2->succs) != 2
1626 : 6907867 : || !any_condjump_p (BB_END (bb2))
1627 : 22905956 : || !onlyjump_p (BB_END (bb2)))
1628 : 9181402 : return false;
1629 : :
1630 : 6862277 : b1 = BRANCH_EDGE (bb1);
1631 : 6862277 : b2 = BRANCH_EDGE (bb2);
1632 : 6862277 : f1 = FALLTHRU_EDGE (bb1);
1633 : 6862277 : f2 = FALLTHRU_EDGE (bb2);
1634 : :
1635 : : /* Get around possible forwarders on fallthru edges. Other cases
1636 : : should be optimized out already. */
1637 : 6862277 : if (FORWARDER_BLOCK_P (f1->dest))
1638 : 2453612 : f1 = single_succ_edge (f1->dest);
1639 : :
1640 : 6862277 : if (FORWARDER_BLOCK_P (f2->dest))
1641 : 1730005 : f2 = single_succ_edge (f2->dest);
1642 : :
1643 : : /* To simplify use of this function, return false if there are
1644 : : unneeded forwarder blocks. These will get eliminated later
1645 : : during cleanup_cfg. */
1646 : 6862277 : if (FORWARDER_BLOCK_P (f1->dest)
1647 : 6858938 : || FORWARDER_BLOCK_P (f2->dest)
1648 : 6854613 : || FORWARDER_BLOCK_P (b1->dest)
1649 : 6840844 : || FORWARDER_BLOCK_P (b2->dest))
1650 : : return false;
1651 : :
1652 : 6834614 : if (f1->dest == f2->dest && b1->dest == b2->dest)
1653 : : reverse = false;
1654 : 6636902 : else if (f1->dest == b2->dest && b1->dest == f2->dest)
1655 : : reverse = true;
1656 : : else
1657 : : return false;
1658 : :
1659 : 283623 : set1 = pc_set (BB_END (bb1));
1660 : 283623 : set2 = pc_set (BB_END (bb2));
1661 : 283623 : if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
1662 : 283623 : != (XEXP (SET_SRC (set2), 1) == pc_rtx))
1663 : 0 : reverse = !reverse;
1664 : :
1665 : 283623 : cond1 = XEXP (SET_SRC (set1), 0);
1666 : 283623 : cond2 = XEXP (SET_SRC (set2), 0);
1667 : 283623 : code1 = GET_CODE (cond1);
1668 : 283623 : if (reverse)
1669 : 85911 : code2 = reversed_comparison_code (cond2, BB_END (bb2));
1670 : : else
1671 : 197712 : code2 = GET_CODE (cond2);
1672 : :
1673 : 283623 : if (code2 == UNKNOWN)
1674 : : return false;
1675 : :
1676 : : /* Verify codes and operands match. */
1677 : 793977 : match = ((code1 == code2
1678 : 234578 : && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
1679 : 231909 : && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
1680 : 286292 : || (code1 == swap_condition (code2)
1681 : 4048 : && rtx_renumbered_equal_p (XEXP (cond1, 1),
1682 : 4048 : XEXP (cond2, 0))
1683 : 0 : && rtx_renumbered_equal_p (XEXP (cond1, 0),
1684 : 0 : XEXP (cond2, 1))));
1685 : :
1686 : : /* If we return true, we will join the blocks. Which means that
1687 : : we will only have one branch prediction bit to work with. Thus
1688 : : we require the existing branches to have probabilities that are
1689 : : roughly similar. */
1690 : 231909 : if (match
1691 : 231909 : && optimize_bb_for_speed_p (bb1)
1692 : 215029 : && optimize_bb_for_speed_p (bb2))
1693 : : {
1694 : 208073 : profile_probability prob2;
1695 : :
1696 : 208073 : if (b1->dest == b2->dest)
1697 : 146450 : prob2 = b2->probability;
1698 : : else
1699 : : /* Do not use f2 probability as f2 may be forwarded. */
1700 : 61623 : prob2 = b2->probability.invert ();
1701 : :
1702 : : /* Fail if the difference in probabilities is greater than 50%.
1703 : : This rules out two well-predicted branches with opposite
1704 : : outcomes. */
1705 : 208073 : if (b1->probability.differs_lot_from_p (prob2))
1706 : : {
1707 : 5178 : if (dump_file)
1708 : : {
1709 : 0 : fprintf (dump_file,
1710 : : "Outcomes of branch in bb %i and %i differ too"
1711 : : " much (", bb1->index, bb2->index);
1712 : 0 : b1->probability.dump (dump_file);
1713 : 0 : prob2.dump (dump_file);
1714 : 0 : fprintf (dump_file, ")\n");
1715 : : }
1716 : 5178 : return false;
1717 : : }
1718 : : }
1719 : :
1720 : 278445 : if (dump_file && match)
1721 : 16 : fprintf (dump_file, "Conditionals in bb %i and %i match.\n",
1722 : : bb1->index, bb2->index);
1723 : :
1724 : 278445 : return match;
1725 : : }
1726 : :
1727 : : /* Generic case - we are seeing a computed jump, table jump or trapping
1728 : : instruction. */
1729 : :
1730 : : /* Check whether there are tablejumps in the end of BB1 and BB2.
1731 : : Return true if they are identical. */
1732 : 11812377 : {
1733 : 11812377 : rtx_insn *label1, *label2;
1734 : 11812377 : rtx_jump_table_data *table1, *table2;
1735 : :
1736 : 11812377 : if (tablejump_p (BB_END (bb1), &label1, &table1)
1737 : 97579 : && tablejump_p (BB_END (bb2), &label2, &table2)
1738 : 11813304 : && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2)))
1739 : : {
1740 : : /* The labels should never be the same rtx. If they really are same
1741 : : the jump tables are same too. So disable crossjumping of blocks BB1
1742 : : and BB2 because when deleting the common insns in the end of BB1
1743 : : by delete_basic_block () the jump table would be deleted too. */
1744 : : /* If LABEL2 is referenced in BB1->END do not do anything
1745 : : because we would loose information when replacing
1746 : : LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */
1747 : 927 : if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1)))
1748 : : {
1749 : : /* Set IDENTICAL to true when the tables are identical. */
1750 : 927 : bool identical = false;
1751 : 927 : rtx p1, p2;
1752 : :
1753 : 927 : p1 = PATTERN (table1);
1754 : 927 : p2 = PATTERN (table2);
1755 : 927 : if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2))
1756 : : {
1757 : : identical = true;
1758 : : }
1759 : 922 : else if (GET_CODE (p1) == ADDR_DIFF_VEC
1760 : 274 : && (XVECLEN (p1, 1) == XVECLEN (p2, 1))
1761 : 144 : && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2))
1762 : 1066 : && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3)))
1763 : : {
1764 : 144 : int i;
1765 : :
1766 : 144 : identical = true;
1767 : 570 : for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--)
1768 : 426 : if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i)))
1769 : : identical = false;
1770 : : }
1771 : :
1772 : 144 : if (identical)
1773 : : {
1774 : 10 : bool match;
1775 : :
1776 : : /* Temporarily replace references to LABEL1 with LABEL2
1777 : : in BB1->END so that we could compare the instructions. */
1778 : 10 : replace_label_in_insn (BB_END (bb1), label1, label2, false);
1779 : :
1780 : 10 : match = (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2))
1781 : : == dir_both);
1782 : 10 : if (dump_file && match)
1783 : 0 : fprintf (dump_file,
1784 : : "Tablejumps in bb %i and %i match.\n",
1785 : : bb1->index, bb2->index);
1786 : :
1787 : : /* Set the original label in BB1->END because when deleting
1788 : : a block whose end is a tablejump, the tablejump referenced
1789 : : from the instruction is deleted too. */
1790 : 10 : replace_label_in_insn (BB_END (bb1), label2, label1, false);
1791 : :
1792 : 927 : return match;
1793 : : }
1794 : : }
1795 : 917 : return false;
1796 : : }
1797 : : }
1798 : :
1799 : : /* Find the last non-debug non-note instruction in each bb, except
1800 : : stop when we see the NOTE_INSN_BASIC_BLOCK, as old_insns_match_p
1801 : : handles that case specially. old_insns_match_p does not handle
1802 : : other types of instruction notes. */
1803 : 11811450 : rtx_insn *last1 = BB_END (bb1);
1804 : 11811450 : rtx_insn *last2 = BB_END (bb2);
1805 : 11811541 : while (!NOTE_INSN_BASIC_BLOCK_P (last1) &&
1806 : 11770842 : (DEBUG_INSN_P (last1) || NOTE_P (last1)))
1807 : 91 : last1 = PREV_INSN (last1);
1808 : 11883341 : while (!NOTE_INSN_BASIC_BLOCK_P (last2) &&
1809 : 11775234 : (DEBUG_INSN_P (last2) || NOTE_P (last2)))
1810 : 71891 : last2 = PREV_INSN (last2);
1811 : 11811450 : gcc_assert (last1 && last2);
1812 : :
1813 : : /* First ensure that the instructions match. There may be many outgoing
1814 : : edges so this test is generally cheaper. */
1815 : 11811450 : if (old_insns_match_p (mode, last1, last2) != dir_both)
1816 : : return false;
1817 : :
1818 : : /* Search the outgoing edges, ensure that the counts do match, find possible
1819 : : fallthru and exception handling edges since these needs more
1820 : : validation. */
1821 : 6096948 : if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs))
1822 : : return false;
1823 : :
1824 : 2032265 : bool nonfakeedges = false;
1825 : 4864435 : FOR_EACH_EDGE (e1, ei, bb1->succs)
1826 : : {
1827 : 2832170 : e2 = EDGE_SUCC (bb2, ei.index);
1828 : :
1829 : 2832170 : if ((e1->flags & EDGE_FAKE) == 0)
1830 : 1916783 : nonfakeedges = true;
1831 : :
1832 : 2832170 : if (e1->flags & EDGE_EH)
1833 : 903002 : nehedges1++;
1834 : :
1835 : 2832170 : if (e2->flags & EDGE_EH)
1836 : 903002 : nehedges2++;
1837 : :
1838 : 2832170 : if (e1->flags & EDGE_FALLTHRU)
1839 : 837317 : fallthru1 = e1;
1840 : 2832170 : if (e2->flags & EDGE_FALLTHRU)
1841 : 837317 : fallthru2 = e2;
1842 : : }
1843 : :
1844 : : /* If number of edges of various types does not match, fail. */
1845 : 2032265 : if (nehedges1 != nehedges2
1846 : 2032265 : || (fallthru1 != 0) != (fallthru2 != 0))
1847 : : return false;
1848 : :
1849 : : /* If !ACCUMULATE_OUTGOING_ARGS, bb1 (and bb2) have no successors
1850 : : and the last real insn doesn't have REG_ARGS_SIZE note, don't
1851 : : attempt to optimize, as the two basic blocks might have different
1852 : : REG_ARGS_SIZE depths. For noreturn calls and unconditional
1853 : : traps there should be REG_ARG_SIZE notes, they could be missing
1854 : : for __builtin_unreachable () uses though. */
1855 : 2032265 : if (!nonfakeedges
1856 : 915387 : && !ACCUMULATE_OUTGOING_ARGS
1857 : 2947186 : && (!INSN_P (last1)
1858 : 914921 : || !find_reg_note (last1, REG_ARGS_SIZE, NULL)))
1859 : 9 : return false;
1860 : :
1861 : : /* fallthru edges must be forwarded to the same destination. */
1862 : 2032256 : if (fallthru1)
1863 : : {
1864 : 837317 : basic_block d1 = (FORWARDER_BLOCK_P (fallthru1->dest)
1865 : 837317 : ? single_succ (fallthru1->dest) : fallthru1->dest);
1866 : 837317 : basic_block d2 = (FORWARDER_BLOCK_P (fallthru2->dest)
1867 : 837317 : ? single_succ (fallthru2->dest) : fallthru2->dest);
1868 : :
1869 : 837317 : if (d1 != d2)
1870 : : return false;
1871 : : }
1872 : :
1873 : : /* Ensure the same EH region. */
1874 : 1510774 : {
1875 : 1510774 : rtx n1 = find_reg_note (last1, REG_EH_REGION, 0);
1876 : 1510774 : rtx n2 = find_reg_note (last2, REG_EH_REGION, 0);
1877 : :
1878 : 1510774 : if (!n1 && n2)
1879 : : return false;
1880 : :
1881 : 1510774 : if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0)))
1882 : : return false;
1883 : : }
1884 : :
1885 : : /* The same checks as in try_crossjump_to_edge. It is required for RTL
1886 : : version of sequence abstraction. */
1887 : 3299624 : FOR_EACH_EDGE (e1, ei, bb2->succs)
1888 : : {
1889 : 1788939 : edge e2;
1890 : 1788939 : edge_iterator ei;
1891 : 1788939 : basic_block d1 = e1->dest;
1892 : :
1893 : 1788939 : if (FORWARDER_BLOCK_P (d1))
1894 : 361069 : d1 = EDGE_SUCC (d1, 0)->dest;
1895 : :
1896 : 2067733 : FOR_EACH_EDGE (e2, ei, bb1->succs)
1897 : : {
1898 : 2067733 : basic_block d2 = e2->dest;
1899 : 2067733 : if (FORWARDER_BLOCK_P (d2))
1900 : 508568 : d2 = EDGE_SUCC (d2, 0)->dest;
1901 : 2067733 : if (d1 == d2)
1902 : : break;
1903 : : }
1904 : :
1905 : 1788939 : if (!e2)
1906 : 0 : return false;
1907 : : }
1908 : :
1909 : : return true;
1910 : : }
1911 : :
1912 : : /* Returns true if BB basic block has a preserve label. */
1913 : :
1914 : : static bool
1915 : 370878 : block_has_preserve_label (basic_block bb)
1916 : : {
1917 : 370878 : return (bb
1918 : 370878 : && block_label (bb)
1919 : 688883 : && LABEL_PRESERVE_P (block_label (bb)));
1920 : : }
1921 : :
1922 : : /* E1 and E2 are edges with the same destination block. Search their
1923 : : predecessors for common code. If found, redirect control flow from
1924 : : (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward),
1925 : : or the other way around (dir_backward). DIR specifies the allowed
1926 : : replacement direction. */
1927 : :
1928 : : static bool
1929 : 45612722 : try_crossjump_to_edge (int mode, edge e1, edge e2,
1930 : : enum replace_direction dir)
1931 : : {
1932 : 45612722 : int nmatch;
1933 : 45612722 : basic_block src1 = e1->src, src2 = e2->src;
1934 : 45612722 : basic_block redirect_to, redirect_from, to_remove;
1935 : 45612722 : basic_block osrc1, osrc2, redirect_edges_to, tmp;
1936 : 45612722 : rtx_insn *newpos1, *newpos2;
1937 : 45612722 : edge s;
1938 : 45612722 : edge_iterator ei;
1939 : :
1940 : 45612722 : newpos1 = newpos2 = NULL;
1941 : :
1942 : : /* Search backward through forwarder blocks. We don't need to worry
1943 : : about multiple entry or chained forwarders, as they will be optimized
1944 : : away. We do this to look past the unconditional jump following a
1945 : : conditional jump that is required due to the current CFG shape. */
1946 : 45612722 : if (single_pred_p (src1)
1947 : 45612722 : && FORWARDER_BLOCK_P (src1))
1948 : 9431205 : e1 = single_pred_edge (src1), src1 = e1->src;
1949 : :
1950 : 45612722 : if (single_pred_p (src2)
1951 : 45612517 : && FORWARDER_BLOCK_P (src2))
1952 : 4559436 : e2 = single_pred_edge (src2), src2 = e2->src;
1953 : :
1954 : : /* Nothing to do if we reach ENTRY, or a common source block. */
1955 : 45612722 : if (src1 == ENTRY_BLOCK_PTR_FOR_FN (cfun) || src2
1956 : : == ENTRY_BLOCK_PTR_FOR_FN (cfun))
1957 : : return false;
1958 : 45612312 : if (src1 == src2)
1959 : : return false;
1960 : :
1961 : : /* Seeing more than 1 forwarder blocks would confuse us later... */
1962 : 45612209 : if (FORWARDER_BLOCK_P (e1->dest)
1963 : 45612209 : && FORWARDER_BLOCK_P (single_succ (e1->dest)))
1964 : : return false;
1965 : :
1966 : 45602210 : if (FORWARDER_BLOCK_P (e2->dest)
1967 : 45602210 : && FORWARDER_BLOCK_P (single_succ (e2->dest)))
1968 : : return false;
1969 : :
1970 : : /* Likewise with dead code (possibly newly created by the other optimizations
1971 : : of cfg_cleanup). */
1972 : 45601528 : if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0)
1973 : : return false;
1974 : :
1975 : : /* Do not turn corssing edge to non-crossing or vice versa after reload. */
1976 : 41044639 : if (BB_PARTITION (src1) != BB_PARTITION (src2)
1977 : 99087 : && reload_completed)
1978 : : return false;
1979 : :
1980 : : /* Look for the common insn sequence, part the first ... */
1981 : 40945552 : if (!outgoing_edges_match (mode, src1, src2))
1982 : : return false;
1983 : :
1984 : : /* ... and part the second. */
1985 : 13405782 : nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir);
1986 : :
1987 : 13405782 : osrc1 = src1;
1988 : 13405782 : osrc2 = src2;
1989 : 13405782 : if (newpos1 != NULL_RTX)
1990 : 4472462 : src1 = BLOCK_FOR_INSN (newpos1);
1991 : 13405782 : if (newpos2 != NULL_RTX)
1992 : 4472462 : src2 = BLOCK_FOR_INSN (newpos2);
1993 : :
1994 : : /* Check that SRC1 and SRC2 have preds again. They may have changed
1995 : : above due to the call to flow_find_cross_jump. */
1996 : 58719709 : if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0)
1997 : : return false;
1998 : :
1999 : 13405782 : if (dir == dir_backward)
2000 : : {
2001 : 2267 : std::swap (osrc1, osrc2);
2002 : 2267 : std::swap (src1, src2);
2003 : 2267 : std::swap (e1, e2);
2004 : 2267 : std::swap (newpos1, newpos2);
2005 : : }
2006 : :
2007 : : /* Don't proceed with the crossjump unless we found a sufficient number
2008 : : of matching instructions or the 'from' block was totally matched
2009 : : (such that its predecessors will hopefully be redirected and the
2010 : : block removed). */
2011 : 13405782 : if ((nmatch < param_min_crossjump_insns)
2012 : 13295602 : && (newpos1 != BB_HEAD (src1)))
2013 : : return false;
2014 : :
2015 : : /* Avoid deleting preserve label when redirecting ABNORMAL edges. */
2016 : 370878 : if (block_has_preserve_label (e1->dest)
2017 : 370878 : && (e1->flags & EDGE_ABNORMAL))
2018 : : return false;
2019 : :
2020 : : /* Here we know that the insns in the end of SRC1 which are common with SRC2
2021 : : will be deleted.
2022 : : If we have tablejumps in the end of SRC1 and SRC2
2023 : : they have been already compared for equivalence in outgoing_edges_match ()
2024 : : so replace the references to TABLE1 by references to TABLE2. */
2025 : 298795 : {
2026 : 298795 : rtx_insn *label1, *label2;
2027 : 298795 : rtx_jump_table_data *table1, *table2;
2028 : :
2029 : 298795 : if (tablejump_p (BB_END (osrc1), &label1, &table1)
2030 : 5 : && tablejump_p (BB_END (osrc2), &label2, &table2)
2031 : 298800 : && label1 != label2)
2032 : : {
2033 : 5 : rtx_insn *insn;
2034 : :
2035 : : /* Replace references to LABEL1 with LABEL2. */
2036 : 9687 : for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2037 : : {
2038 : : /* Do not replace the label in SRC1->END because when deleting
2039 : : a block whose end is a tablejump, the tablejump referenced
2040 : : from the instruction is deleted too. */
2041 : 9682 : if (insn != BB_END (osrc1))
2042 : 9677 : replace_label_in_insn (insn, label1, label2, true);
2043 : : }
2044 : : }
2045 : : }
2046 : :
2047 : : /* Avoid splitting if possible. We must always split when SRC2 has
2048 : : EH predecessor edges, or we may end up with basic blocks with both
2049 : : normal and EH predecessor edges. */
2050 : 298795 : if (newpos2 == BB_HEAD (src2)
2051 : 298795 : && !(EDGE_PRED (src2, 0)->flags & EDGE_EH))
2052 : : redirect_to = src2;
2053 : : else
2054 : : {
2055 : 69504 : if (newpos2 == BB_HEAD (src2))
2056 : : {
2057 : : /* Skip possible basic block header. */
2058 : 5577 : if (LABEL_P (newpos2))
2059 : 5577 : newpos2 = NEXT_INSN (newpos2);
2060 : 5577 : while (DEBUG_INSN_P (newpos2))
2061 : 0 : newpos2 = NEXT_INSN (newpos2);
2062 : 5577 : if (NOTE_P (newpos2))
2063 : 5577 : newpos2 = NEXT_INSN (newpos2);
2064 : 6088 : while (DEBUG_INSN_P (newpos2))
2065 : 511 : newpos2 = NEXT_INSN (newpos2);
2066 : : }
2067 : :
2068 : 69504 : if (dump_file)
2069 : 0 : fprintf (dump_file, "Splitting bb %i before %i insns\n",
2070 : : src2->index, nmatch);
2071 : 69504 : redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
2072 : : }
2073 : :
2074 : 298795 : if (dump_file)
2075 : 0 : fprintf (dump_file,
2076 : : "Cross jumping from bb %i to bb %i; %i common insns\n",
2077 : : src1->index, src2->index, nmatch);
2078 : :
2079 : : /* We may have some registers visible through the block. */
2080 : 298795 : df_set_bb_dirty (redirect_to);
2081 : :
2082 : 298795 : if (osrc2 == src2)
2083 : : redirect_edges_to = redirect_to;
2084 : : else
2085 : 11262 : redirect_edges_to = osrc2;
2086 : :
2087 : : /* Recompute the counts of destinations of outgoing edges. */
2088 : 654163 : FOR_EACH_EDGE (s, ei, redirect_edges_to->succs)
2089 : : {
2090 : 355368 : edge s2;
2091 : 355368 : edge_iterator ei;
2092 : 355368 : basic_block d = s->dest;
2093 : :
2094 : 355368 : if (FORWARDER_BLOCK_P (d))
2095 : 23194 : d = single_succ (d);
2096 : :
2097 : 412160 : FOR_EACH_EDGE (s2, ei, src1->succs)
2098 : : {
2099 : 412160 : basic_block d2 = s2->dest;
2100 : 412160 : if (FORWARDER_BLOCK_P (d2))
2101 : 84332 : d2 = single_succ (d2);
2102 : 412160 : if (d == d2)
2103 : : break;
2104 : : }
2105 : :
2106 : : /* Take care to update possible forwarder blocks. We verified
2107 : : that there is no more than one in the chain, so we can't run
2108 : : into infinite loop. */
2109 : 355368 : if (FORWARDER_BLOCK_P (s->dest))
2110 : 23194 : s->dest->count += s->count ();
2111 : :
2112 : 355368 : if (FORWARDER_BLOCK_P (s2->dest))
2113 : 65524 : s2->dest->count -= s->count ();
2114 : :
2115 : 355368 : s->probability = s->probability.combine_with_count
2116 : 355368 : (redirect_edges_to->count,
2117 : : s2->probability, src1->count);
2118 : : }
2119 : :
2120 : : /* Adjust count for the block. An earlier jump
2121 : : threading pass may have left the profile in an inconsistent
2122 : : state (see update_bb_profile_for_threading) so we must be
2123 : : prepared for overflows. */
2124 : : tmp = redirect_to;
2125 : 323281 : do
2126 : : {
2127 : 311038 : tmp->count += src1->count;
2128 : 311038 : if (tmp == redirect_edges_to)
2129 : : break;
2130 : 12243 : tmp = find_fallthru_edge (tmp->succs)->dest;
2131 : : }
2132 : : while (true);
2133 : 298795 : update_br_prob_note (redirect_edges_to);
2134 : :
2135 : : /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */
2136 : :
2137 : : /* Skip possible basic block header. */
2138 : 298795 : if (LABEL_P (newpos1))
2139 : 120235 : newpos1 = NEXT_INSN (newpos1);
2140 : :
2141 : 310089 : while (DEBUG_INSN_P (newpos1))
2142 : 11294 : newpos1 = NEXT_INSN (newpos1);
2143 : :
2144 : 298795 : if (NOTE_INSN_BASIC_BLOCK_P (newpos1))
2145 : 220173 : newpos1 = NEXT_INSN (newpos1);
2146 : :
2147 : : /* Skip also prologue and function markers. */
2148 : 724006 : while (DEBUG_INSN_P (newpos1)
2149 : 724006 : || (NOTE_P (newpos1)
2150 : 14196 : && (NOTE_KIND (newpos1) == NOTE_INSN_PROLOGUE_END
2151 : 14196 : || NOTE_KIND (newpos1) == NOTE_INSN_FUNCTION_BEG)))
2152 : 425211 : newpos1 = NEXT_INSN (newpos1);
2153 : :
2154 : 298795 : redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
2155 : 298795 : to_remove = single_succ (redirect_from);
2156 : :
2157 : 298795 : redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to);
2158 : 298795 : delete_basic_block (to_remove);
2159 : :
2160 : 298795 : update_forwarder_flag (redirect_from);
2161 : 298795 : if (redirect_to != src2)
2162 : 69504 : update_forwarder_flag (src2);
2163 : :
2164 : : return true;
2165 : : }
2166 : :
2167 : : /* Search the predecessors of BB for common insn sequences. When found,
2168 : : share code between them by redirecting control flow. Return true if
2169 : : any changes made. */
2170 : :
2171 : : static bool
2172 : 27615354 : try_crossjump_bb (int mode, basic_block bb)
2173 : : {
2174 : 27615354 : edge e, e2, fallthru;
2175 : 27615354 : bool changed;
2176 : 27615354 : unsigned max, ix, ix2;
2177 : :
2178 : : /* Nothing to do if there is not at least two incoming edges. */
2179 : 27812066 : if (EDGE_COUNT (bb->preds) < 2)
2180 : : return false;
2181 : :
2182 : : /* Don't crossjump if this block ends in a computed jump,
2183 : : unless we are optimizing for size. */
2184 : 7564280 : if (optimize_bb_for_size_p (bb)
2185 : 1204664 : && bb != EXIT_BLOCK_PTR_FOR_FN (cfun)
2186 : 8736204 : && computed_jump_p (BB_END (bb)))
2187 : : return false;
2188 : :
2189 : : /* If we are partitioning hot/cold basic blocks, we don't want to
2190 : : mess up unconditional or indirect jumps that cross between hot
2191 : : and cold sections.
2192 : :
2193 : : Basic block partitioning may result in some jumps that appear to
2194 : : be optimizable (or blocks that appear to be mergeable), but which really
2195 : : must be left untouched (they are required to make it safely across
2196 : : partition boundaries). See the comments at the top of
2197 : : bb-reorder.cc:partition_hot_cold_basic_blocks for complete details. */
2198 : :
2199 : 7564265 : if (BB_PARTITION (EDGE_PRED (bb, 0)->src) !=
2200 : 7564265 : BB_PARTITION (EDGE_PRED (bb, 1)->src)
2201 : 7564265 : || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING))
2202 : : return false;
2203 : :
2204 : : /* It is always cheapest to redirect a block that ends in a branch to
2205 : : a block that falls through into BB, as that adds no branches to the
2206 : : program. We'll try that combination first. */
2207 : 7371359 : fallthru = NULL;
2208 : 7371359 : max = param_max_crossjump_edges;
2209 : :
2210 : 7371359 : if (EDGE_COUNT (bb->preds) > max)
2211 : : return false;
2212 : :
2213 : 7367568 : fallthru = find_fallthru_edge (bb->preds);
2214 : :
2215 : 7367568 : changed = false;
2216 : 35979948 : for (ix = 0; ix < EDGE_COUNT (bb->preds);)
2217 : : {
2218 : 21244812 : e = EDGE_PRED (bb, ix);
2219 : 21244812 : ix++;
2220 : :
2221 : : /* As noted above, first try with the fallthru predecessor (or, a
2222 : : fallthru predecessor if we are in cfglayout mode). */
2223 : 21244812 : if (fallthru)
2224 : : {
2225 : : /* Don't combine the fallthru edge into anything else.
2226 : : If there is a match, we'll do it the other way around. */
2227 : 15289179 : if (e == fallthru)
2228 : 5832480 : continue;
2229 : : /* If nothing changed since the last attempt, there is nothing
2230 : : we can do. */
2231 : 9456699 : if (!first_pass
2232 : 3718569 : && !((e->src->flags & BB_MODIFIED)
2233 : 2943912 : || (fallthru->src->flags & BB_MODIFIED)))
2234 : 2620168 : continue;
2235 : :
2236 : 6836531 : if (try_crossjump_to_edge (mode, e, fallthru, dir_forward))
2237 : : {
2238 : 121436 : changed = true;
2239 : 121436 : ix = 0;
2240 : 121436 : continue;
2241 : : }
2242 : : }
2243 : :
2244 : : /* Non-obvious work limiting check: Recognize that we're going
2245 : : to call try_crossjump_bb on every basic block. So if we have
2246 : : two blocks with lots of outgoing edges (a switch) and they
2247 : : share lots of common destinations, then we would do the
2248 : : cross-jump check once for each common destination.
2249 : :
2250 : : Now, if the blocks actually are cross-jump candidates, then
2251 : : all of their destinations will be shared. Which means that
2252 : : we only need check them for cross-jump candidacy once. We
2253 : : can eliminate redundant checks of crossjump(A,B) by arbitrarily
2254 : : choosing to do the check from the block for which the edge
2255 : : in question is the first successor of A. */
2256 : 12670728 : if (EDGE_SUCC (e->src, 0) != e)
2257 : 2503252 : continue;
2258 : :
2259 : 150912973 : for (ix2 = 0; ix2 < EDGE_COUNT (bb->preds); ix2++)
2260 : : {
2261 : 112310476 : e2 = EDGE_PRED (bb, ix2);
2262 : :
2263 : 112310476 : if (e2 == e)
2264 : 10082941 : continue;
2265 : :
2266 : : /* We've already checked the fallthru edge above. */
2267 : 102227535 : if (e2 == fallthru)
2268 : 5416106 : continue;
2269 : :
2270 : : /* The "first successor" check above only prevents multiple
2271 : : checks of crossjump(A,B). In order to prevent redundant
2272 : : checks of crossjump(B,A), require that A be the block
2273 : : with the lowest index. */
2274 : 96811429 : if (e->src->index > e2->src->index)
2275 : 48364128 : continue;
2276 : :
2277 : : /* If nothing changed since the last attempt, there is nothing
2278 : : we can do. */
2279 : 48447301 : if (!first_pass
2280 : 12693210 : && !((e->src->flags & BB_MODIFIED)
2281 : 10557549 : || (e2->src->flags & BB_MODIFIED)))
2282 : 9671110 : continue;
2283 : :
2284 : : /* Both e and e2 are not fallthru edges, so we can crossjump in either
2285 : : direction. */
2286 : 38776191 : if (try_crossjump_to_edge (mode, e, e2, dir_both))
2287 : : {
2288 : : changed = true;
2289 : : ix = 0;
2290 : : break;
2291 : : }
2292 : : }
2293 : : }
2294 : :
2295 : 7367568 : if (changed)
2296 : 146569 : crossjumps_occurred = true;
2297 : :
2298 : : return changed;
2299 : : }
2300 : :
2301 : : /* Search the successors of BB for common insn sequences. When found,
2302 : : share code between them by moving it across the basic block
2303 : : boundary. Return true if any changes made. */
2304 : :
2305 : : static bool
2306 : 26475544 : try_head_merge_bb (basic_block bb)
2307 : : {
2308 : 26475544 : basic_block final_dest_bb = NULL;
2309 : 26475544 : int max_match = INT_MAX;
2310 : 26475544 : edge e0;
2311 : 26475544 : rtx_insn **headptr, **currptr, **nextptr;
2312 : 26475544 : bool changed, moveall;
2313 : 26475544 : unsigned ix;
2314 : 26475544 : rtx_insn *e0_last_head;
2315 : 26475544 : rtx cond;
2316 : 26475544 : rtx_insn *move_before;
2317 : 26475544 : unsigned nedges = EDGE_COUNT (bb->succs);
2318 : 26475544 : rtx_insn *jump = BB_END (bb);
2319 : 26475544 : regset live, live_union;
2320 : :
2321 : : /* Nothing to do if there is not at least two outgoing edges. */
2322 : 26475544 : if (nedges < 2)
2323 : : return false;
2324 : :
2325 : : /* Don't crossjump if this block ends in a computed jump,
2326 : : unless we are optimizing for size. */
2327 : 13519474 : if (optimize_bb_for_size_p (bb)
2328 : 1515817 : && bb != EXIT_BLOCK_PTR_FOR_FN (cfun)
2329 : 15035291 : && computed_jump_p (BB_END (bb)))
2330 : : return false;
2331 : :
2332 : 13519452 : cond = get_condition (jump, &move_before, true, false);
2333 : 13519452 : if (cond == NULL_RTX)
2334 : 1964456 : move_before = jump;
2335 : :
2336 : 40825847 : for (ix = 0; ix < nedges; ix++)
2337 : 27306395 : if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
2338 : : return false;
2339 : :
2340 : 24901691 : for (ix = 0; ix < nedges; ix++)
2341 : : {
2342 : 20884050 : edge e = EDGE_SUCC (bb, ix);
2343 : 20884050 : basic_block other_bb = e->dest;
2344 : :
2345 : 20884050 : if (df_get_bb_dirty (other_bb))
2346 : : {
2347 : 513635 : block_was_dirty = true;
2348 : 513635 : return false;
2349 : : }
2350 : :
2351 : 20370415 : if (e->flags & EDGE_ABNORMAL)
2352 : : return false;
2353 : :
2354 : : /* Normally, all destination blocks must only be reachable from this
2355 : : block, i.e. they must have one incoming edge.
2356 : :
2357 : : There is one special case we can handle, that of multiple consecutive
2358 : : jumps where the first jumps to one of the targets of the second jump.
2359 : : This happens frequently in switch statements for default labels.
2360 : : The structure is as follows:
2361 : : FINAL_DEST_BB
2362 : : ....
2363 : : if (cond) jump A;
2364 : : fall through
2365 : : BB
2366 : : jump with targets A, B, C, D...
2367 : : A
2368 : : has two incoming edges, from FINAL_DEST_BB and BB
2369 : :
2370 : : In this case, we can try to move the insns through BB and into
2371 : : FINAL_DEST_BB. */
2372 : 18490654 : if (EDGE_COUNT (other_bb->preds) != 1)
2373 : : {
2374 : 7414173 : edge incoming_edge, incoming_bb_other_edge;
2375 : 7414173 : edge_iterator ei;
2376 : :
2377 : 7414173 : if (final_dest_bb != NULL
2378 : 7414173 : || EDGE_COUNT (other_bb->preds) != 2)
2379 : 7108415 : return false;
2380 : :
2381 : : /* We must be able to move the insns across the whole block. */
2382 : 3997575 : move_before = BB_HEAD (bb);
2383 : 24181239 : while (!NONDEBUG_INSN_P (move_before))
2384 : 20183664 : move_before = NEXT_INSN (move_before);
2385 : :
2386 : 3997575 : if (EDGE_COUNT (bb->preds) != 1)
2387 : : return false;
2388 : 2408744 : incoming_edge = EDGE_PRED (bb, 0);
2389 : 2408744 : final_dest_bb = incoming_edge->src;
2390 : 9031370 : if (EDGE_COUNT (final_dest_bb->succs) != 2)
2391 : : return false;
2392 : 2736300 : FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs)
2393 : 2736300 : if (incoming_bb_other_edge != incoming_edge)
2394 : : break;
2395 : 1922955 : if (incoming_bb_other_edge->dest != other_bb)
2396 : : return false;
2397 : : }
2398 : : }
2399 : :
2400 : 4017641 : e0 = EDGE_SUCC (bb, 0);
2401 : 4017641 : e0_last_head = NULL;
2402 : 4017641 : changed = false;
2403 : :
2404 : 4115021 : for (ix = 1; ix < nedges; ix++)
2405 : : {
2406 : 4024175 : edge e = EDGE_SUCC (bb, ix);
2407 : 4024175 : rtx_insn *e0_last, *e_last;
2408 : 4024175 : int nmatch;
2409 : :
2410 : 4024175 : nmatch = flow_find_head_matching_sequence (e0->dest, e->dest,
2411 : : &e0_last, &e_last, 0);
2412 : 4024175 : if (nmatch == 0)
2413 : 3926795 : return false;
2414 : :
2415 : 97380 : if (nmatch < max_match)
2416 : : {
2417 : 91109 : max_match = nmatch;
2418 : 91109 : e0_last_head = e0_last;
2419 : : }
2420 : : }
2421 : :
2422 : : /* If we matched an entire block, we probably have to avoid moving the
2423 : : last insn. */
2424 : 90846 : if (max_match > 0
2425 : 90846 : && e0_last_head == BB_END (e0->dest)
2426 : 98763 : && (find_reg_note (e0_last_head, REG_EH_REGION, 0)
2427 : 6401 : || control_flow_insn_p (e0_last_head)))
2428 : : {
2429 : 1527 : max_match--;
2430 : 1527 : if (max_match == 0)
2431 : : return false;
2432 : 230 : e0_last_head = prev_real_nondebug_insn (e0_last_head);
2433 : : }
2434 : :
2435 : 89549 : if (max_match == 0)
2436 : : return false;
2437 : :
2438 : : /* We must find a union of the live registers at each of the end points. */
2439 : 89549 : live = BITMAP_ALLOC (NULL);
2440 : 89549 : live_union = BITMAP_ALLOC (NULL);
2441 : :
2442 : 89549 : currptr = XNEWVEC (rtx_insn *, nedges);
2443 : 89549 : headptr = XNEWVEC (rtx_insn *, nedges);
2444 : 89549 : nextptr = XNEWVEC (rtx_insn *, nedges);
2445 : :
2446 : 274630 : for (ix = 0; ix < nedges; ix++)
2447 : : {
2448 : 185081 : int j;
2449 : 185081 : basic_block merge_bb = EDGE_SUCC (bb, ix)->dest;
2450 : 185081 : rtx_insn *head = BB_HEAD (merge_bb);
2451 : :
2452 : 1015381 : while (!NONDEBUG_INSN_P (head))
2453 : 830300 : head = NEXT_INSN (head);
2454 : 185081 : headptr[ix] = head;
2455 : 185081 : currptr[ix] = head;
2456 : :
2457 : : /* Compute the end point and live information */
2458 : 317452 : for (j = 1; j < max_match; j++)
2459 : 175737 : do
2460 : 175737 : head = NEXT_INSN (head);
2461 : 175737 : while (!NONDEBUG_INSN_P (head));
2462 : 185081 : simulate_backwards_to_point (merge_bb, live, head);
2463 : 185081 : IOR_REG_SET (live_union, live);
2464 : : }
2465 : :
2466 : : /* If we're moving across two blocks, verify the validity of the
2467 : : first move, then adjust the target and let the loop below deal
2468 : : with the final move. */
2469 : 89549 : if (final_dest_bb != NULL)
2470 : : {
2471 : 7337 : rtx_insn *move_upto;
2472 : :
2473 : 7337 : moveall = can_move_insns_across (currptr[0], e0_last_head, move_before,
2474 : : jump, e0->dest, live_union,
2475 : : NULL, &move_upto);
2476 : 7337 : if (!moveall)
2477 : : {
2478 : 6254 : if (move_upto == NULL_RTX)
2479 : 5793 : goto out;
2480 : :
2481 : 1282 : while (e0_last_head != move_upto)
2482 : : {
2483 : 821 : df_simulate_one_insn_backwards (e0->dest, e0_last_head,
2484 : : live_union);
2485 : 821 : e0_last_head = PREV_INSN (e0_last_head);
2486 : : }
2487 : : }
2488 : 1544 : if (e0_last_head == NULL_RTX)
2489 : 0 : goto out;
2490 : :
2491 : 1544 : jump = BB_END (final_dest_bb);
2492 : 1544 : cond = get_condition (jump, &move_before, true, false);
2493 : 1544 : if (cond == NULL_RTX)
2494 : 0 : move_before = jump;
2495 : : }
2496 : :
2497 : 141594 : do
2498 : : {
2499 : 141594 : rtx_insn *move_upto;
2500 : 141594 : moveall = can_move_insns_across (currptr[0], e0_last_head,
2501 : : move_before, jump, e0->dest, live_union,
2502 : : NULL, &move_upto);
2503 : 141594 : if (!moveall && move_upto == NULL_RTX)
2504 : : {
2505 : 108339 : if (jump == move_before)
2506 : : break;
2507 : :
2508 : : /* Try again, using a different insertion point. */
2509 : 55131 : move_before = jump;
2510 : :
2511 : 55131 : continue;
2512 : : }
2513 : :
2514 : 33255 : if (final_dest_bb && !moveall)
2515 : : /* We haven't checked whether a partial move would be OK for the first
2516 : : move, so we have to fail this case. */
2517 : : break;
2518 : :
2519 : 47981 : changed = true;
2520 : 47981 : for (;;)
2521 : : {
2522 : 47981 : if (currptr[0] == move_upto)
2523 : : break;
2524 : 44558 : for (ix = 0; ix < nedges; ix++)
2525 : : {
2526 : 29821 : rtx_insn *curr = currptr[ix];
2527 : 47044 : do
2528 : 47044 : curr = NEXT_INSN (curr);
2529 : 47044 : while (!NONDEBUG_INSN_P (curr));
2530 : 29821 : currptr[ix] = curr;
2531 : : }
2532 : : }
2533 : :
2534 : : /* If we can't currently move all of the identical insns, remember
2535 : : each insn after the range that we'll merge. */
2536 : 33244 : if (!moveall)
2537 : 10335 : for (ix = 0; ix < nedges; ix++)
2538 : : {
2539 : 6910 : rtx_insn *curr = currptr[ix];
2540 : 9421 : do
2541 : 9421 : curr = NEXT_INSN (curr);
2542 : 9421 : while (!NONDEBUG_INSN_P (curr));
2543 : 6910 : nextptr[ix] = curr;
2544 : : }
2545 : :
2546 : 33244 : reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before));
2547 : 33244 : df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest);
2548 : 33244 : if (final_dest_bb != NULL)
2549 : 1531 : df_set_bb_dirty (final_dest_bb);
2550 : 33244 : df_set_bb_dirty (bb);
2551 : 101634 : for (ix = 1; ix < nedges; ix++)
2552 : : {
2553 : 35146 : df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest);
2554 : 35146 : delete_insn_chain (headptr[ix], currptr[ix], false);
2555 : : }
2556 : 33244 : if (!moveall)
2557 : : {
2558 : 3425 : if (jump == move_before)
2559 : : break;
2560 : :
2561 : : /* For the unmerged insns, try a different insertion point. */
2562 : 2707 : move_before = jump;
2563 : :
2564 : 8121 : for (ix = 0; ix < nedges; ix++)
2565 : 5414 : currptr[ix] = headptr[ix] = nextptr[ix];
2566 : : }
2567 : : }
2568 : 87657 : while (!moveall);
2569 : :
2570 : 29819 : out:
2571 : 89549 : free (currptr);
2572 : 89549 : free (headptr);
2573 : 89549 : free (nextptr);
2574 : :
2575 : 89549 : crossjumps_occurred |= changed;
2576 : :
2577 : 89549 : return changed;
2578 : : }
2579 : :
2580 : : /* Return true if BB contains just bb note, or bb note followed
2581 : : by only DEBUG_INSNs. */
2582 : :
2583 : : static bool
2584 : 15018911 : trivially_empty_bb_p (basic_block bb)
2585 : : {
2586 : 15018911 : rtx_insn *insn = BB_END (bb);
2587 : :
2588 : 14665 : while (1)
2589 : : {
2590 : 15033576 : if (insn == BB_HEAD (bb))
2591 : : return true;
2592 : 15032857 : if (!DEBUG_INSN_P (insn))
2593 : : return false;
2594 : 14665 : insn = PREV_INSN (insn);
2595 : : }
2596 : : }
2597 : :
2598 : : /* Return true if BB contains just a return and possibly a USE of the
2599 : : return value. Fill in *RET and *USE with the return and use insns
2600 : : if any found, otherwise NULL. All CLOBBERs are ignored. */
2601 : :
2602 : : bool
2603 : 370195391 : bb_is_just_return (basic_block bb, rtx_insn **ret, rtx_insn **use)
2604 : : {
2605 : 370195391 : *ret = *use = NULL;
2606 : 370195391 : rtx_insn *insn;
2607 : :
2608 : 370195391 : if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
2609 : : return false;
2610 : :
2611 : 482177085 : FOR_BB_INSNS_REVERSE (bb, insn)
2612 : 469553164 : if (NONDEBUG_INSN_P (insn))
2613 : : {
2614 : 366334815 : rtx pat = PATTERN (insn);
2615 : :
2616 : 366334815 : if (!*ret && ANY_RETURN_P (pat))
2617 : 7415419 : *ret = insn;
2618 : 7738996 : else if (*ret && !*use && GET_CODE (pat) == USE
2619 : 1064965 : && REG_P (XEXP (pat, 0))
2620 : 359984361 : && REG_FUNCTION_VALUE_P (XEXP (pat, 0)))
2621 : 1061558 : *use = insn;
2622 : 357857838 : else if (GET_CODE (pat) != CLOBBER)
2623 : : return false;
2624 : : }
2625 : :
2626 : 12623921 : return !!*ret;
2627 : : }
2628 : :
2629 : : /* Do simple CFG optimizations - basic block merging, simplifying of jump
2630 : : instructions etc. Return nonzero if changes were made. */
2631 : :
2632 : : static bool
2633 : 20835284 : try_optimize_cfg (int mode)
2634 : : {
2635 : 20835284 : bool changed_overall = false;
2636 : 20835284 : bool changed;
2637 : 20835284 : int iterations = 0;
2638 : 20835284 : basic_block bb, b, next;
2639 : :
2640 : 20835284 : if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING))
2641 : 2855195 : clear_bb_flags ();
2642 : :
2643 : 20835284 : crossjumps_occurred = false;
2644 : :
2645 : 295249571 : FOR_EACH_BB_FN (bb, cfun)
2646 : 274414287 : update_forwarder_flag (bb);
2647 : :
2648 : 20835284 : if (! targetm.cannot_modify_jumps_p ())
2649 : : {
2650 : 20835284 : first_pass = true;
2651 : : /* Attempt to merge blocks as made possible by edge removal. If
2652 : : a block has only one successor, and the successor has only
2653 : : one predecessor, they may be combined. */
2654 : 48985248 : do
2655 : : {
2656 : 24492624 : block_was_dirty = false;
2657 : 24492624 : changed = false;
2658 : 24492624 : iterations++;
2659 : :
2660 : 24492624 : if (dump_file)
2661 : 1603 : fprintf (dump_file,
2662 : : "\n\ntry_optimize_cfg iteration %i\n\n",
2663 : : iterations);
2664 : :
2665 : 24492624 : for (b = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; b
2666 : 400442968 : != EXIT_BLOCK_PTR_FOR_FN (cfun);)
2667 : : {
2668 : 375950344 : basic_block c;
2669 : 375950344 : edge s;
2670 : 375950344 : bool changed_here = false;
2671 : :
2672 : : /* Delete trivially dead basic blocks. This is either
2673 : : blocks with no predecessors, or empty blocks with no
2674 : : successors. However if the empty block with no
2675 : : successors is the successor of the ENTRY_BLOCK, it is
2676 : : kept. This ensures that the ENTRY_BLOCK will have a
2677 : : successor which is a precondition for many RTL
2678 : : passes. Empty blocks may result from expanding
2679 : : __builtin_unreachable (). */
2680 : 375950344 : if (EDGE_COUNT (b->preds) == 0
2681 : 375950344 : || (EDGE_COUNT (b->succs) == 0
2682 : 15018911 : && trivially_empty_bb_p (b)
2683 : 719 : && single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))->dest
2684 : : != b))
2685 : : {
2686 : 5171968 : c = b->prev_bb;
2687 : 5171968 : if (EDGE_COUNT (b->preds) > 0)
2688 : : {
2689 : 719 : edge e;
2690 : 719 : edge_iterator ei;
2691 : :
2692 : 719 : if (current_ir_type () == IR_RTL_CFGLAYOUT)
2693 : : {
2694 : 53 : rtx_insn *insn;
2695 : 53 : for (insn = BB_FOOTER (b);
2696 : 53 : insn; insn = NEXT_INSN (insn))
2697 : 53 : if (BARRIER_P (insn))
2698 : : break;
2699 : 53 : if (insn)
2700 : 106 : FOR_EACH_EDGE (e, ei, b->preds)
2701 : 53 : if ((e->flags & EDGE_FALLTHRU))
2702 : : {
2703 : 53 : if (BB_FOOTER (b)
2704 : 53 : && BB_FOOTER (e->src) == NULL)
2705 : : {
2706 : 53 : BB_FOOTER (e->src) = BB_FOOTER (b);
2707 : 53 : BB_FOOTER (b) = NULL;
2708 : : }
2709 : : else
2710 : 0 : emit_barrier_after_bb (e->src);
2711 : : }
2712 : : }
2713 : : else
2714 : : {
2715 : 666 : rtx_insn *last = get_last_bb_insn (b);
2716 : 666 : if (last && BARRIER_P (last))
2717 : 1332 : FOR_EACH_EDGE (e, ei, b->preds)
2718 : 666 : if ((e->flags & EDGE_FALLTHRU))
2719 : 666 : emit_barrier_after (BB_END (e->src));
2720 : : }
2721 : : }
2722 : 5171968 : delete_basic_block (b);
2723 : 5171968 : changed = true;
2724 : : /* Avoid trying to remove the exit block. */
2725 : 5171968 : b = (c == ENTRY_BLOCK_PTR_FOR_FN (cfun) ? c->next_bb : c);
2726 : 5297333 : continue;
2727 : 5171968 : }
2728 : :
2729 : : /* Remove code labels no longer used. */
2730 : 370778376 : if (single_pred_p (b)
2731 : 270246789 : && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
2732 : 189473964 : && !(single_pred_edge (b)->flags & EDGE_COMPLEX)
2733 : 186786917 : && LABEL_P (BB_HEAD (b))
2734 : 858147 : && !LABEL_PRESERVE_P (BB_HEAD (b))
2735 : : /* If the previous block ends with a branch to this
2736 : : block, we can't delete the label. Normally this
2737 : : is a condjump that is yet to be simplified, but
2738 : : if CASE_DROPS_THRU, this can be a tablejump with
2739 : : some element going to the same place as the
2740 : : default (fallthru). */
2741 : 371622574 : && (single_pred (b) == ENTRY_BLOCK_PTR_FOR_FN (cfun)
2742 : 844144 : || !JUMP_P (BB_END (single_pred (b)))
2743 : 649261 : || ! label_is_jump_target_p (BB_HEAD (b),
2744 : 649261 : BB_END (single_pred (b)))))
2745 : : {
2746 : 839339 : delete_insn (BB_HEAD (b));
2747 : 839339 : if (dump_file)
2748 : 30 : fprintf (dump_file, "Deleted label in block %i.\n",
2749 : : b->index);
2750 : : }
2751 : :
2752 : : /* If we fall through an empty block, we can remove it. */
2753 : 370903741 : if (!(mode & (CLEANUP_CFGLAYOUT | CLEANUP_NO_INSN_DEL))
2754 : 77782912 : && single_pred_p (b)
2755 : 57608862 : && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
2756 : 40864723 : && !LABEL_P (BB_HEAD (b))
2757 : 40549764 : && FORWARDER_BLOCK_P (b)
2758 : : /* Note that forwarder_block_p true ensures that
2759 : : there is a successor for this block. */
2760 : 5113612 : && (single_succ_edge (b)->flags & EDGE_FALLTHRU)
2761 : 370985849 : && n_basic_blocks_for_fn (cfun) > NUM_FIXED_BLOCKS + 1)
2762 : : {
2763 : 125365 : if (dump_file)
2764 : 7 : fprintf (dump_file,
2765 : : "Deleting fallthru block %i.\n",
2766 : : b->index);
2767 : :
2768 : 250730 : c = ((b->prev_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun))
2769 : 125365 : ? b->next_bb : b->prev_bb);
2770 : 125365 : redirect_edge_succ_nodup (single_pred_edge (b),
2771 : : single_succ (b));
2772 : 125365 : delete_basic_block (b);
2773 : 125365 : changed = true;
2774 : 125365 : b = c;
2775 : 125365 : continue;
2776 : : }
2777 : :
2778 : : /* Merge B with its single successor, if any. */
2779 : 370653011 : if (single_succ_p (b)
2780 : 163473855 : && (s = single_succ_edge (b))
2781 : 163473855 : && !(s->flags & EDGE_COMPLEX)
2782 : 155220429 : && (c = s->dest) != EXIT_BLOCK_PTR_FOR_FN (cfun)
2783 : 379418733 : && single_pred_p (c)
2784 : 377949343 : && b != c)
2785 : : {
2786 : : /* When not in cfg_layout mode use code aware of reordering
2787 : : INSN. This code possibly creates new basic blocks so it
2788 : : does not fit merge_blocks interface and is kept here in
2789 : : hope that it will become useless once more of compiler
2790 : : is transformed to use cfg_layout mode. */
2791 : :
2792 : 8765722 : if ((mode & CLEANUP_CFGLAYOUT)
2793 : 8765722 : && can_merge_blocks_p (b, c))
2794 : : {
2795 : 778948 : merge_blocks (b, c);
2796 : 778948 : update_forwarder_flag (b);
2797 : 778948 : changed_here = true;
2798 : : }
2799 : 7986774 : else if (!(mode & CLEANUP_CFGLAYOUT)
2800 : : /* If the jump insn has side effects,
2801 : : we can't kill the edge. */
2802 : 6798318 : && (!JUMP_P (BB_END (b))
2803 : 2222948 : || (reload_completed
2804 : 3157724 : ? simplejump_p (BB_END (b))
2805 : 934776 : : (onlyjump_p (BB_END (b))
2806 : 934134 : && !tablejump_p (BB_END (b),
2807 : : NULL, NULL))))
2808 : 17941421 : && (next = merge_blocks_move (s, b, c, mode)))
2809 : : {
2810 : : b = next;
2811 : : changed_here = true;
2812 : : }
2813 : : }
2814 : :
2815 : : /* Try to change a branch to a return to just that return. */
2816 : 370653011 : rtx_insn *ret, *use;
2817 : 370653011 : if (single_succ_p (b)
2818 : 161901760 : && onlyjump_p (BB_END (b))
2819 : 396566902 : && bb_is_just_return (single_succ (b), &ret, &use))
2820 : : {
2821 : 32378 : if (redirect_jump (as_a <rtx_jump_insn *> (BB_END (b)),
2822 : 32378 : PATTERN (ret), 0))
2823 : : {
2824 : 32378 : if (use)
2825 : 18475 : emit_insn_before (copy_insn (PATTERN (use)),
2826 : 18475 : BB_END (b));
2827 : 32378 : if (dump_file)
2828 : 25 : fprintf (dump_file, "Changed jump %d->%d to return.\n",
2829 : 25 : b->index, single_succ (b)->index);
2830 : 32378 : redirect_edge_succ (single_succ_edge (b),
2831 : 32378 : EXIT_BLOCK_PTR_FOR_FN (cfun));
2832 : 32378 : single_succ_edge (b)->flags &= ~EDGE_CROSSING;
2833 : 32378 : changed_here = true;
2834 : : }
2835 : : }
2836 : :
2837 : : /* Try to change a conditional branch to a return to the
2838 : : respective conditional return. */
2839 : 370653011 : if (EDGE_COUNT (b->succs) == 2
2840 : 193309885 : && any_condjump_p (BB_END (b))
2841 : 538592368 : && bb_is_just_return (BRANCH_EDGE (b)->dest, &ret, &use))
2842 : : {
2843 : 564639 : if (redirect_jump (as_a <rtx_jump_insn *> (BB_END (b)),
2844 : 564639 : PATTERN (ret), 0))
2845 : : {
2846 : 0 : if (use)
2847 : 0 : emit_insn_before (copy_insn (PATTERN (use)),
2848 : 0 : BB_END (b));
2849 : 0 : if (dump_file)
2850 : 0 : fprintf (dump_file, "Changed conditional jump %d->%d "
2851 : : "to conditional return.\n",
2852 : 0 : b->index, BRANCH_EDGE (b)->dest->index);
2853 : 0 : redirect_edge_succ (BRANCH_EDGE (b),
2854 : 0 : EXIT_BLOCK_PTR_FOR_FN (cfun));
2855 : 0 : BRANCH_EDGE (b)->flags &= ~EDGE_CROSSING;
2856 : 0 : changed_here = true;
2857 : : }
2858 : : }
2859 : :
2860 : : /* Try to flip a conditional branch that falls through to
2861 : : a return so that it becomes a conditional return and a
2862 : : new jump to the original branch target. */
2863 : 370653011 : if (EDGE_COUNT (b->succs) == 2
2864 : 193309885 : && BRANCH_EDGE (b)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
2865 : 193309885 : && any_condjump_p (BB_END (b))
2866 : 538592368 : && bb_is_just_return (FALLTHRU_EDGE (b)->dest, &ret, &use))
2867 : : {
2868 : 146868 : if (invert_jump (as_a <rtx_jump_insn *> (BB_END (b)),
2869 : 146868 : JUMP_LABEL (BB_END (b)), 0))
2870 : : {
2871 : 146868 : basic_block new_ft = BRANCH_EDGE (b)->dest;
2872 : 146868 : if (redirect_jump (as_a <rtx_jump_insn *> (BB_END (b)),
2873 : 146868 : PATTERN (ret), 0))
2874 : : {
2875 : 0 : if (use)
2876 : 0 : emit_insn_before (copy_insn (PATTERN (use)),
2877 : 0 : BB_END (b));
2878 : 0 : if (dump_file)
2879 : 0 : fprintf (dump_file, "Changed conditional jump "
2880 : : "%d->%d to conditional return, adding "
2881 : : "fall-through jump.\n",
2882 : 0 : b->index, BRANCH_EDGE (b)->dest->index);
2883 : 0 : redirect_edge_succ (BRANCH_EDGE (b),
2884 : 0 : EXIT_BLOCK_PTR_FOR_FN (cfun));
2885 : 0 : BRANCH_EDGE (b)->flags &= ~EDGE_CROSSING;
2886 : 0 : std::swap (BRANCH_EDGE (b)->probability,
2887 : 0 : FALLTHRU_EDGE (b)->probability);
2888 : 0 : update_br_prob_note (b);
2889 : 0 : basic_block jb = force_nonfallthru (FALLTHRU_EDGE (b));
2890 : 0 : notice_new_block (jb);
2891 : 0 : if (!redirect_jump (as_a <rtx_jump_insn *> (BB_END (jb)),
2892 : 0 : block_label (new_ft), 0))
2893 : 0 : gcc_unreachable ();
2894 : 0 : redirect_edge_succ (single_succ_edge (jb), new_ft);
2895 : 0 : changed_here = true;
2896 : : }
2897 : : else
2898 : : {
2899 : : /* Invert the jump back to what it was. This should
2900 : : never fail. */
2901 : 146868 : if (!invert_jump (as_a <rtx_jump_insn *> (BB_END (b)),
2902 : 146868 : JUMP_LABEL (BB_END (b)), 0))
2903 : 0 : gcc_unreachable ();
2904 : : }
2905 : : }
2906 : : }
2907 : :
2908 : : /* Simplify branch over branch. */
2909 : 370653011 : if ((mode & CLEANUP_EXPENSIVE)
2910 : : && !(mode & CLEANUP_CFGLAYOUT)
2911 : 370653011 : && try_simplify_condjump (b))
2912 : : changed_here = true;
2913 : :
2914 : : /* If B has a single outgoing edge, but uses a
2915 : : non-trivial jump instruction without side-effects, we
2916 : : can either delete the jump entirely, or replace it
2917 : : with a simple unconditional jump. */
2918 : 370653011 : if (single_succ_p (b)
2919 : 161901796 : && single_succ (b) != EXIT_BLOCK_PTR_FOR_FN (cfun)
2920 : 133613884 : && onlyjump_p (BB_END (b))
2921 : 27414653 : && !CROSSING_JUMP_P (BB_END (b))
2922 : 395556696 : && try_redirect_by_replacing_jump (single_succ_edge (b),
2923 : : single_succ (b),
2924 : 26437422 : (mode & CLEANUP_CFGLAYOUT) != 0))
2925 : : {
2926 : 3976187 : update_forwarder_flag (b);
2927 : 3976187 : changed_here = true;
2928 : : }
2929 : :
2930 : : /* Simplify branch to branch. */
2931 : 370653011 : if (try_forward_edges (mode, b))
2932 : : {
2933 : 6206948 : update_forwarder_flag (b);
2934 : 6206948 : changed_here = true;
2935 : : }
2936 : :
2937 : : /* Look for shared code between blocks. */
2938 : 370653011 : if ((mode & CLEANUP_CROSSJUMP)
2939 : 370653011 : && try_crossjump_bb (mode, b))
2940 : : changed_here = true;
2941 : :
2942 : 370653011 : if ((mode & CLEANUP_CROSSJUMP)
2943 : : /* This can lengthen register lifetimes. Do it only after
2944 : : reload. */
2945 : 26475544 : && reload_completed
2946 : 397128555 : && try_head_merge_bb (b))
2947 : : changed_here = true;
2948 : :
2949 : : /* Don't get confused by the index shift caused by
2950 : : deleting blocks. */
2951 : 370620440 : if (!changed_here)
2952 : 356496442 : b = b->next_bb;
2953 : : else
2954 : : changed = true;
2955 : : }
2956 : :
2957 : 24492624 : if ((mode & CLEANUP_CROSSJUMP)
2958 : 24492624 : && try_crossjump_bb (mode, EXIT_BLOCK_PTR_FOR_FN (cfun)))
2959 : : changed = true;
2960 : :
2961 : 24492624 : if (block_was_dirty)
2962 : : {
2963 : : /* This should only be set by head-merging. */
2964 : 187654 : gcc_assert (mode & CLEANUP_CROSSJUMP);
2965 : 187654 : df_analyze ();
2966 : : }
2967 : :
2968 : 24492624 : if (changed)
2969 : : {
2970 : : /* Edge forwarding in particular can cause hot blocks previously
2971 : : reached by both hot and cold blocks to become dominated only
2972 : : by cold blocks. This will cause the verification below to fail,
2973 : : and lead to now cold code in the hot section. This is not easy
2974 : : to detect and fix during edge forwarding, and in some cases
2975 : : is only visible after newly unreachable blocks are deleted,
2976 : : which will be done in fixup_partitions. */
2977 : 3657340 : if ((mode & CLEANUP_NO_PARTITIONING) == 0)
2978 : : {
2979 : 3535073 : fixup_partitions ();
2980 : 3535073 : checking_verify_flow_info ();
2981 : : }
2982 : : }
2983 : :
2984 : 24492624 : changed_overall |= changed;
2985 : 24492624 : first_pass = false;
2986 : : }
2987 : : while (changed);
2988 : : }
2989 : :
2990 : 327250900 : FOR_ALL_BB_FN (b, cfun)
2991 : 306415616 : b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK);
2992 : :
2993 : 20835284 : return changed_overall;
2994 : : }
2995 : :
2996 : : /* Delete all unreachable basic blocks. */
2997 : :
2998 : : bool
2999 : 26900473 : delete_unreachable_blocks (void)
3000 : : {
3001 : 26900473 : bool changed = false;
3002 : 26900473 : basic_block b, prev_bb;
3003 : :
3004 : 26900473 : find_unreachable_blocks ();
3005 : :
3006 : : /* When we're in GIMPLE mode and there may be debug bind insns, we
3007 : : should delete blocks in reverse dominator order, so as to get a
3008 : : chance to substitute all released DEFs into debug bind stmts. If
3009 : : we don't have dominators information, walking blocks backward
3010 : : gets us a better chance of retaining most debug information than
3011 : : otherwise. */
3012 : 12099674 : if (MAY_HAVE_DEBUG_BIND_INSNS && current_ir_type () == IR_GIMPLE
3013 : 27145121 : && dom_info_available_p (CDI_DOMINATORS))
3014 : : {
3015 : 0 : for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb;
3016 : 0 : b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb)
3017 : : {
3018 : 0 : prev_bb = b->prev_bb;
3019 : :
3020 : 0 : if (!(b->flags & BB_REACHABLE))
3021 : : {
3022 : : /* Speed up the removal of blocks that don't dominate
3023 : : others. Walking backwards, this should be the common
3024 : : case. */
3025 : 0 : if (!first_dom_son (CDI_DOMINATORS, b))
3026 : 0 : delete_basic_block (b);
3027 : : else
3028 : : {
3029 : 0 : auto_vec<basic_block> h
3030 : 0 : = get_all_dominated_blocks (CDI_DOMINATORS, b);
3031 : :
3032 : 0 : while (h.length ())
3033 : : {
3034 : 0 : b = h.pop ();
3035 : :
3036 : 0 : prev_bb = b->prev_bb;
3037 : :
3038 : 0 : gcc_assert (!(b->flags & BB_REACHABLE));
3039 : :
3040 : 0 : delete_basic_block (b);
3041 : : }
3042 : 0 : }
3043 : :
3044 : : changed = true;
3045 : : }
3046 : : }
3047 : : }
3048 : : else
3049 : : {
3050 : 26900473 : for (b = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb;
3051 : 385449690 : b != ENTRY_BLOCK_PTR_FOR_FN (cfun); b = prev_bb)
3052 : : {
3053 : 358549217 : prev_bb = b->prev_bb;
3054 : :
3055 : 358549217 : if (!(b->flags & BB_REACHABLE))
3056 : : {
3057 : 1650809 : delete_basic_block (b);
3058 : 1650809 : changed = true;
3059 : : }
3060 : : }
3061 : : }
3062 : :
3063 : 26900473 : if (changed)
3064 : 408332 : tidy_fallthru_edges ();
3065 : 26900473 : return changed;
3066 : : }
3067 : :
3068 : : /* Delete any jump tables never referenced. We can't delete them at the
3069 : : time of removing tablejump insn as they are referenced by the preceding
3070 : : insns computing the destination, so we delay deleting and garbagecollect
3071 : : them once life information is computed. */
3072 : : void
3073 : 8736320 : delete_dead_jumptables (void)
3074 : : {
3075 : 8736320 : basic_block bb;
3076 : :
3077 : : /* A dead jump table does not belong to any basic block. Scan insns
3078 : : between two adjacent basic blocks. */
3079 : 94912237 : FOR_EACH_BB_FN (bb, cfun)
3080 : : {
3081 : 86175917 : rtx_insn *insn, *next;
3082 : :
3083 : 86175917 : for (insn = NEXT_INSN (BB_END (bb));
3084 : 157693862 : insn && !NOTE_INSN_BASIC_BLOCK_P (insn);
3085 : : insn = next)
3086 : : {
3087 : 71517945 : next = NEXT_INSN (insn);
3088 : 71517945 : if (LABEL_P (insn)
3089 : 40282559 : && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
3090 : 73326957 : && JUMP_TABLE_DATA_P (next))
3091 : : {
3092 : 0 : rtx_insn *label = insn, *jump = next;
3093 : :
3094 : 0 : if (dump_file)
3095 : 0 : fprintf (dump_file, "Dead jumptable %i removed\n",
3096 : 0 : INSN_UID (insn));
3097 : :
3098 : 0 : next = NEXT_INSN (next);
3099 : 0 : delete_insn (jump);
3100 : 0 : delete_insn (label);
3101 : : }
3102 : : }
3103 : : }
3104 : 8736320 : }
3105 : :
3106 : :
3107 : : /* Tidy the CFG by deleting unreachable code and whatnot. */
3108 : :
3109 : : bool
3110 : 18799991 : cleanup_cfg (int mode)
3111 : : {
3112 : 18799991 : bool changed = false;
3113 : :
3114 : : /* Set the cfglayout mode flag here. We could update all the callers
3115 : : but that is just inconvenient, especially given that we eventually
3116 : : want to have cfglayout mode as the default. */
3117 : 18799991 : if (current_ir_type () == IR_RTL_CFGLAYOUT)
3118 : 12477894 : mode |= CLEANUP_CFGLAYOUT;
3119 : :
3120 : 18799991 : timevar_push (TV_CLEANUP_CFG);
3121 : 18799991 : if (delete_unreachable_blocks ())
3122 : : {
3123 : 139209 : changed = true;
3124 : : /* We've possibly created trivially dead code. Cleanup it right
3125 : : now to introduce more opportunities for try_optimize_cfg. */
3126 : 139209 : if (!(mode & (CLEANUP_NO_INSN_DEL))
3127 : 41082 : && !reload_completed)
3128 : 41024 : delete_trivially_dead_insns (get_insns (), max_reg_num ());
3129 : : }
3130 : :
3131 : 18799991 : compact_blocks ();
3132 : :
3133 : : /* To tail-merge blocks ending in the same noreturn function (e.g.
3134 : : a call to abort) we have to insert fake edges to exit. Do this
3135 : : here once. The fake edges do not interfere with any other CFG
3136 : : cleanups. */
3137 : 18799991 : if (mode & CLEANUP_CROSSJUMP)
3138 : 924056 : add_noreturn_fake_exit_edges ();
3139 : :
3140 : 18799991 : if (!dbg_cnt (cfg_cleanup))
3141 : : return changed;
3142 : :
3143 : 20835284 : while (try_optimize_cfg (mode))
3144 : : {
3145 : 3560239 : delete_unreachable_blocks (), changed = true;
3146 : 3560239 : if (!(mode & CLEANUP_NO_INSN_DEL))
3147 : : {
3148 : : /* Try to remove some trivially dead insns when doing an expensive
3149 : : cleanup. But delete_trivially_dead_insns doesn't work after
3150 : : reload (it only handles pseudos) and run_fast_dce is too costly
3151 : : to run in every iteration.
3152 : :
3153 : : For effective cross jumping, we really want to run a fast DCE to
3154 : : clean up any dead conditions, or they get in the way of performing
3155 : : useful tail merges.
3156 : :
3157 : : Other transformations in cleanup_cfg are not so sensitive to dead
3158 : : code, so delete_trivially_dead_insns or even doing nothing at all
3159 : : is good enough. */
3160 : 587044 : if ((mode & CLEANUP_EXPENSIVE) && !reload_completed
3161 : 2101390 : && !delete_trivially_dead_insns (get_insns (), max_reg_num ()))
3162 : : break;
3163 : 2035293 : if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occurred)
3164 : : {
3165 : 74497 : run_fast_dce ();
3166 : 74497 : mode &= ~CLEANUP_FORCE_FAST_DCE;
3167 : : }
3168 : : }
3169 : : else
3170 : : break;
3171 : : }
3172 : :
3173 : 18799991 : if (mode & CLEANUP_CROSSJUMP)
3174 : 924056 : remove_fake_exit_edges ();
3175 : :
3176 : 18799991 : if (mode & CLEANUP_FORCE_FAST_DCE)
3177 : 124425 : run_fast_dce ();
3178 : :
3179 : : /* Don't call delete_dead_jumptables in cfglayout mode, because
3180 : : that function assumes that jump tables are in the insns stream.
3181 : : But we also don't _have_ to delete dead jumptables in cfglayout
3182 : : mode because we shouldn't even be looking at things that are
3183 : : not in a basic block. Dead jumptables are cleaned up when
3184 : : going out of cfglayout mode. */
3185 : 18799991 : if (!(mode & CLEANUP_CFGLAYOUT))
3186 : 6322097 : delete_dead_jumptables ();
3187 : :
3188 : : /* ??? We probably do this way too often. */
3189 : 18799991 : if (current_loops
3190 : 8755514 : && (changed
3191 : 6458055 : || (mode & CLEANUP_CFG_CHANGED)))
3192 : : {
3193 : 2382659 : timevar_push (TV_REPAIR_LOOPS);
3194 : : /* The above doesn't preserve dominance info if available. */
3195 : 2382659 : gcc_assert (!dom_info_available_p (CDI_DOMINATORS));
3196 : 2382659 : calculate_dominance_info (CDI_DOMINATORS);
3197 : 2382659 : fix_loop_structure (NULL);
3198 : 2382659 : free_dominance_info (CDI_DOMINATORS);
3199 : 2382659 : timevar_pop (TV_REPAIR_LOOPS);
3200 : : }
3201 : :
3202 : 18799991 : timevar_pop (TV_CLEANUP_CFG);
3203 : :
3204 : 18799991 : return changed;
3205 : : }
3206 : :
3207 : : namespace {
3208 : :
3209 : : const pass_data pass_data_jump =
3210 : : {
3211 : : RTL_PASS, /* type */
3212 : : "jump", /* name */
3213 : : OPTGROUP_NONE, /* optinfo_flags */
3214 : : TV_JUMP, /* tv_id */
3215 : : 0, /* properties_required */
3216 : : 0, /* properties_provided */
3217 : : 0, /* properties_destroyed */
3218 : : 0, /* todo_flags_start */
3219 : : 0, /* todo_flags_finish */
3220 : : };
3221 : :
3222 : : class pass_jump : public rtl_opt_pass
3223 : : {
3224 : : public:
3225 : 280114 : pass_jump (gcc::context *ctxt)
3226 : 560228 : : rtl_opt_pass (pass_data_jump, ctxt)
3227 : : {}
3228 : :
3229 : : /* opt_pass methods: */
3230 : : unsigned int execute (function *) final override;
3231 : :
3232 : : }; // class pass_jump
3233 : :
3234 : : unsigned int
3235 : 1415657 : pass_jump::execute (function *)
3236 : : {
3237 : 1415657 : delete_trivially_dead_insns (get_insns (), max_reg_num ());
3238 : 1415657 : if (dump_file)
3239 : 84 : dump_flow_info (dump_file, dump_flags);
3240 : 2831314 : cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0)
3241 : 998292 : | (flag_thread_jumps && flag_expensive_optimizations
3242 : 1415657 : ? CLEANUP_THREADING : 0));
3243 : 1415657 : return 0;
3244 : : }
3245 : :
3246 : : } // anon namespace
3247 : :
3248 : : rtl_opt_pass *
3249 : 280114 : make_pass_jump (gcc::context *ctxt)
3250 : : {
3251 : 280114 : return new pass_jump (ctxt);
3252 : : }
3253 : :
3254 : : namespace {
3255 : :
3256 : : const pass_data pass_data_jump_after_combine =
3257 : : {
3258 : : RTL_PASS, /* type */
3259 : : "jump_after_combine", /* name */
3260 : : OPTGROUP_NONE, /* optinfo_flags */
3261 : : TV_JUMP, /* tv_id */
3262 : : 0, /* properties_required */
3263 : : 0, /* properties_provided */
3264 : : 0, /* properties_destroyed */
3265 : : 0, /* todo_flags_start */
3266 : : 0, /* todo_flags_finish */
3267 : : };
3268 : :
3269 : : class pass_jump_after_combine : public rtl_opt_pass
3270 : : {
3271 : : public:
3272 : 280114 : pass_jump_after_combine (gcc::context *ctxt)
3273 : 560228 : : rtl_opt_pass (pass_data_jump_after_combine, ctxt)
3274 : : {}
3275 : :
3276 : : /* opt_pass methods: */
3277 : 1415668 : bool gate (function *) final override
3278 : : {
3279 : 1415668 : return flag_thread_jumps && flag_expensive_optimizations;
3280 : : }
3281 : : unsigned int execute (function *) final override;
3282 : :
3283 : : }; // class pass_jump_after_combine
3284 : :
3285 : : unsigned int
3286 : 923927 : pass_jump_after_combine::execute (function *)
3287 : : {
3288 : : /* Jump threading does not keep dominators up-to-date. */
3289 : 923927 : free_dominance_info (CDI_DOMINATORS);
3290 : 923927 : cleanup_cfg (CLEANUP_THREADING);
3291 : 923927 : return 0;
3292 : : }
3293 : :
3294 : : } // anon namespace
3295 : :
3296 : : rtl_opt_pass *
3297 : 280114 : make_pass_jump_after_combine (gcc::context *ctxt)
3298 : : {
3299 : 280114 : return new pass_jump_after_combine (ctxt);
3300 : : }
3301 : :
3302 : : namespace {
3303 : :
3304 : : const pass_data pass_data_jump2 =
3305 : : {
3306 : : RTL_PASS, /* type */
3307 : : "jump2", /* name */
3308 : : OPTGROUP_NONE, /* optinfo_flags */
3309 : : TV_JUMP, /* tv_id */
3310 : : 0, /* properties_required */
3311 : : 0, /* properties_provided */
3312 : : 0, /* properties_destroyed */
3313 : : 0, /* todo_flags_start */
3314 : : 0, /* todo_flags_finish */
3315 : : };
3316 : :
3317 : : class pass_jump2 : public rtl_opt_pass
3318 : : {
3319 : : public:
3320 : 280114 : pass_jump2 (gcc::context *ctxt)
3321 : 560228 : : rtl_opt_pass (pass_data_jump2, ctxt)
3322 : : {}
3323 : :
3324 : : /* opt_pass methods: */
3325 : 1415661 : unsigned int execute (function *) final override
3326 : : {
3327 : 1907266 : cleanup_cfg (flag_crossjumping ? CLEANUP_CROSSJUMP : 0);
3328 : 1415661 : return 0;
3329 : : }
3330 : :
3331 : : }; // class pass_jump2
3332 : :
3333 : : } // anon namespace
3334 : :
3335 : : rtl_opt_pass *
3336 : 280114 : make_pass_jump2 (gcc::context *ctxt)
3337 : : {
3338 : 280114 : return new pass_jump2 (ctxt);
3339 : : }
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