Line data Source code
1 : /* Control flow graph building code for GNU compiler.
2 : Copyright (C) 1987-2026 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 :
21 : #include "config.h"
22 : #include "system.h"
23 : #include "coretypes.h"
24 : #include "backend.h"
25 : #include "rtl.h"
26 : #include "cfghooks.h"
27 : #include "memmodel.h"
28 : #include "emit-rtl.h"
29 : #include "cfgrtl.h"
30 : #include "cfganal.h"
31 : #include "cfgbuild.h"
32 : #include "except.h"
33 : #include "stmt.h"
34 :
35 : static void make_edges (basic_block, basic_block, int);
36 : static void make_label_edge (sbitmap, basic_block, rtx, int);
37 : static void find_bb_boundaries (basic_block);
38 : static void compute_outgoing_frequencies (basic_block);
39 :
40 : /* Return true if insn is something that should be contained inside basic
41 : block. */
42 :
43 : bool
44 205144964 : inside_basic_block_p (const rtx_insn *insn)
45 : {
46 205144964 : switch (GET_CODE (insn))
47 : {
48 11774768 : case CODE_LABEL:
49 : /* Avoid creating of basic block for jumptables. */
50 11774768 : return (NEXT_INSN (insn) == 0
51 11774768 : || ! JUMP_TABLE_DATA_P (NEXT_INSN (insn)));
52 :
53 : case JUMP_INSN:
54 : case CALL_INSN:
55 : case INSN:
56 : case DEBUG_INSN:
57 : return true;
58 :
59 : case JUMP_TABLE_DATA:
60 : case BARRIER:
61 : case NOTE:
62 : return false;
63 :
64 0 : default:
65 0 : gcc_unreachable ();
66 : }
67 : }
68 :
69 : /* Return true if INSN may cause control flow transfer, so it should be last in
70 : the basic block. */
71 :
72 : bool
73 11485873992 : control_flow_insn_p (const rtx_insn *insn)
74 : {
75 11485873992 : switch (GET_CODE (insn))
76 : {
77 : case NOTE:
78 : case CODE_LABEL:
79 : case DEBUG_INSN:
80 : return false;
81 :
82 : case JUMP_INSN:
83 : return true;
84 :
85 410303411 : case CALL_INSN:
86 : /* Noreturn and sibling call instructions terminate the basic blocks
87 : (but only if they happen unconditionally). */
88 410303411 : if ((SIBLING_CALL_P (insn)
89 409401550 : || find_reg_note (insn, REG_NORETURN, 0))
90 413829279 : && GET_CODE (PATTERN (insn)) != COND_EXEC)
91 : return true;
92 :
93 : /* Call insn may return to the nonlocal goto handler. */
94 405875682 : if (can_nonlocal_goto (insn))
95 : return true;
96 : break;
97 :
98 5425258194 : case INSN:
99 : /* Treat trap instructions like noreturn calls (same provision). */
100 5425258194 : if (GET_CODE (PATTERN (insn)) == TRAP_IF
101 5425258194 : && XEXP (PATTERN (insn), 0) == const1_rtx)
102 : return true;
103 5425177259 : if (!cfun->can_throw_non_call_exceptions)
104 : return false;
105 : break;
106 :
107 : case JUMP_TABLE_DATA:
108 : case BARRIER:
109 : /* It is nonsense to reach this when looking for the
110 : end of basic block, but before dead code is eliminated
111 : this may happen. */
112 : return false;
113 :
114 0 : default:
115 0 : gcc_unreachable ();
116 : }
117 :
118 1760412832 : return can_throw_internal (insn);
119 : }
120 :
121 :
122 : /* Create an edge between two basic blocks. FLAGS are auxiliary information
123 : about the edge that is accumulated between calls. */
124 :
125 : /* Create an edge from a basic block to a label. */
126 :
127 : static void
128 16288261 : make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags)
129 : {
130 16288261 : gcc_assert (LABEL_P (label));
131 :
132 : /* If the label was never emitted, this insn is junk, but avoid a
133 : crash trying to refer to BLOCK_FOR_INSN (label). This can happen
134 : as a result of a syntax error and a diagnostic has already been
135 : printed. */
136 :
137 16288261 : if (INSN_UID (label) == 0)
138 : return;
139 :
140 16288261 : cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
141 : }
142 :
143 : /* Create the edges generated by INSN in REGION. */
144 :
145 : void
146 9884592 : rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx_insn *insn)
147 : {
148 9884592 : eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn);
149 :
150 9884592 : if (lp)
151 : {
152 1309432 : rtx_insn *label = lp->landing_pad;
153 :
154 : /* During initial rtl generation, use the post_landing_pad. */
155 1309432 : if (label == NULL)
156 : {
157 766610 : gcc_assert (lp->post_landing_pad);
158 766610 : label = label_rtx (lp->post_landing_pad);
159 : }
160 :
161 1309432 : make_label_edge (edge_cache, src, label,
162 : EDGE_ABNORMAL | EDGE_EH
163 1309432 : | (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0));
164 : }
165 9884592 : }
166 :
167 : /* States of basic block as seen by find_many_sub_basic_blocks. */
168 : enum state {
169 : /* Basic blocks created via split_block belong to this state.
170 : make_edges will examine these basic blocks to see if we need to
171 : create edges going out of them. */
172 : BLOCK_NEW = 0,
173 :
174 : /* Basic blocks that do not need examining belong to this state.
175 : These blocks will be left intact. In particular, make_edges will
176 : not create edges going out of these basic blocks. */
177 : BLOCK_ORIGINAL,
178 :
179 : /* Basic blocks that may need splitting (due to a label appearing in
180 : the middle, etc) belong to this state. After splitting them,
181 : make_edges will create edges going out of them as needed. */
182 : BLOCK_TO_SPLIT
183 : };
184 :
185 : #define STATE(BB) (enum state) ((size_t) (BB)->aux)
186 : #define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE))
187 :
188 : /* Used internally by purge_dead_tablejump_edges, ORed into state. */
189 : #define BLOCK_USED_BY_TABLEJUMP 32
190 : #define FULL_STATE(BB) ((size_t) (BB)->aux)
191 :
192 : /* Identify the edges going out of basic blocks between MIN and MAX,
193 : inclusive, that have their states set to BLOCK_NEW or
194 : BLOCK_TO_SPLIT.
195 :
196 : UPDATE_P should be nonzero if we are updating CFG and zero if we
197 : are building CFG from scratch. */
198 :
199 : static void
200 4007259 : make_edges (basic_block min, basic_block max, int update_p)
201 : {
202 4007259 : basic_block bb;
203 4007259 : sbitmap edge_cache = NULL;
204 :
205 : /* Heavy use of computed goto in machine-generated code can lead to
206 : nearly fully-connected CFGs. In that case we spend a significant
207 : amount of time searching the edge lists for duplicates. */
208 4007259 : if (!vec_safe_is_empty (forced_labels)
209 3961559 : || cfun->cfg->max_jumptable_ents > 100)
210 46177 : edge_cache = sbitmap_alloc (last_basic_block_for_fn (cfun));
211 :
212 : /* By nature of the way these get numbered, ENTRY_BLOCK_PTR->next_bb block
213 : is always the entry. */
214 4007259 : if (min == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb)
215 3516007 : make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), min, EDGE_FALLTHRU);
216 :
217 40419269 : FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
218 : {
219 36412010 : rtx_insn *insn;
220 36412010 : enum rtx_code code;
221 36412010 : edge e;
222 36412010 : edge_iterator ei;
223 :
224 36412010 : if (STATE (bb) == BLOCK_ORIGINAL)
225 9326821 : continue;
226 :
227 : /* If we have an edge cache, cache edges going out of BB. */
228 27085189 : if (edge_cache)
229 : {
230 241824 : bitmap_clear (edge_cache);
231 241824 : if (update_p)
232 : {
233 549868 : FOR_EACH_EDGE (e, ei, bb->succs)
234 308044 : if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
235 284995 : bitmap_set_bit (edge_cache, e->dest->index);
236 : }
237 : }
238 :
239 27085189 : if (LABEL_P (BB_HEAD (bb))
240 27085189 : && LABEL_ALT_ENTRY_P (BB_HEAD (bb)))
241 0 : cached_make_edge (NULL, ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
242 :
243 : /* Examine the last instruction of the block, and discover the
244 : ways we can leave the block. */
245 :
246 27085189 : insn = BB_END (bb);
247 27085189 : code = GET_CODE (insn);
248 :
249 : /* A branch. */
250 27085189 : if (code == JUMP_INSN)
251 : {
252 15297747 : rtx tmp;
253 15297747 : rtx_jump_table_data *table;
254 :
255 : /* Recognize a non-local goto as a branch outside the
256 : current function. */
257 15297747 : if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
258 : ;
259 :
260 : /* Recognize a tablejump and do the right thing. */
261 15296311 : else if (tablejump_p (insn, NULL, &table))
262 : {
263 8834 : rtvec vec = table->get_labels ();
264 8834 : int j;
265 :
266 208313 : for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
267 398958 : make_label_edge (edge_cache, bb,
268 199479 : label_ref_label (RTVEC_ELT (vec, j)), 0);
269 :
270 : /* Some targets (eg, ARM) emit a conditional jump that also
271 : contains the out-of-range target. Scan for these and
272 : add an edge if necessary. */
273 8834 : if ((tmp = single_set (insn)) != NULL
274 8834 : && SET_DEST (tmp) == pc_rtx
275 8834 : && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
276 8834 : && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
277 0 : make_label_edge (edge_cache, bb,
278 0 : label_ref_label (XEXP (SET_SRC (tmp), 2)), 0);
279 : }
280 :
281 : /* If this is a computed jump, then mark it as reaching
282 : everything on the forced_labels list. */
283 15287477 : else if (computed_jump_p (insn))
284 : {
285 : rtx_insn *insn;
286 : unsigned int i;
287 15299552 : FOR_EACH_VEC_SAFE_ELT (forced_labels, i, insn)
288 1394 : make_label_edge (edge_cache, bb, insn, EDGE_ABNORMAL);
289 : }
290 :
291 : /* Returns create an exit out. */
292 15287001 : else if (returnjump_p (insn))
293 577696 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0);
294 :
295 : /* Recognize asm goto and do the right thing. */
296 14709305 : else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
297 : {
298 780 : int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
299 1919 : for (i = 0; i < n; ++i)
300 2278 : make_label_edge (edge_cache, bb,
301 1139 : label_ref_label (ASM_OPERANDS_LABEL (tmp, i)),
302 : 0);
303 : }
304 :
305 : /* Otherwise, we have a plain conditional or unconditional jump. */
306 : else
307 : {
308 14708525 : gcc_assert (JUMP_LABEL (insn));
309 14708525 : make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
310 : }
311 : }
312 :
313 : /* If this is a sibling call insn, then this is in effect a combined call
314 : and return, and so we need an edge to the exit block. No need to
315 : worry about EH edges, since we wouldn't have created the sibling call
316 : in the first place. */
317 27085189 : if (code == CALL_INSN && SIBLING_CALL_P (insn))
318 162744 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
319 : EDGE_SIBCALL | EDGE_ABNORMAL);
320 :
321 : /* If this is a CALL_INSN, then mark it as reaching the active EH
322 : handler for this CALL_INSN. If we're handling non-call
323 : exceptions then any insn can reach any of the active handlers.
324 : Also mark the CALL_INSN as reaching any nonlocal goto handler. */
325 26922445 : else if (code == CALL_INSN || cfun->can_throw_non_call_exceptions)
326 : {
327 : /* Add any appropriate EH edges. */
328 9874621 : rtl_make_eh_edge (edge_cache, bb, insn);
329 :
330 9874621 : if (code == CALL_INSN)
331 : {
332 2608692 : if (can_nonlocal_goto (insn))
333 : {
334 : /* ??? This could be made smarter: in some cases it's
335 : possible to tell that certain calls will not do a
336 : nonlocal goto. For example, if the nested functions
337 : that do the nonlocal gotos do not have their addresses
338 : taken, then only calls to those functions or to other
339 : nested functions that use them could possibly do
340 : nonlocal gotos. */
341 72716 : for (rtx_insn_list *x = nonlocal_goto_handler_labels;
342 72716 : x;
343 68292 : x = x->next ())
344 68292 : make_label_edge (edge_cache, bb, x->insn (),
345 : EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
346 : }
347 :
348 2608692 : if (flag_tm)
349 : {
350 1524 : rtx note;
351 5004 : for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
352 3480 : if (REG_NOTE_KIND (note) == REG_TM)
353 0 : make_label_edge (edge_cache, bb, XEXP (note, 0),
354 : EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
355 : }
356 : }
357 : }
358 :
359 : /* Find out if we can drop through to the next block. */
360 27085189 : insn = NEXT_INSN (insn);
361 27085189 : e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun));
362 27085189 : if (e && e->flags & EDGE_FALLTHRU)
363 27085189 : insn = NULL;
364 :
365 : while (insn
366 25173037 : && NOTE_P (insn)
367 39488421 : && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK)
368 3658 : insn = NEXT_INSN (insn);
369 :
370 27085189 : if (!insn)
371 1915810 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
372 : EDGE_FALLTHRU);
373 25169379 : else if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
374 : {
375 24544858 : if (insn == BB_HEAD (bb->next_bb))
376 18710369 : cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU);
377 : }
378 : }
379 :
380 4007259 : if (edge_cache)
381 46177 : sbitmap_free (edge_cache);
382 4007259 : }
383 :
384 : static void
385 169389 : mark_tablejump_edge (rtx_insn *label)
386 : {
387 169389 : basic_block bb;
388 :
389 169389 : gcc_assert (LABEL_P (label));
390 : /* See comment in make_label_edge. */
391 169389 : if (INSN_UID (label) == 0)
392 : return;
393 169389 : bb = BLOCK_FOR_INSN (label);
394 169389 : SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP);
395 : }
396 :
397 : static void
398 7415 : purge_dead_tablejump_edges (basic_block bb, rtx_jump_table_data *table)
399 : {
400 7415 : rtx_insn *insn = BB_END (bb);
401 7415 : rtx tmp;
402 7415 : rtvec vec;
403 7415 : int j;
404 7415 : edge_iterator ei;
405 7415 : edge e;
406 :
407 7415 : vec = table->get_labels ();
408 :
409 176804 : for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
410 169389 : mark_tablejump_edge (label_ref_label (RTVEC_ELT (vec, j)));
411 :
412 : /* Some targets (eg, ARM) emit a conditional jump that also
413 : contains the out-of-range target. Scan for these and
414 : add an edge if necessary. */
415 7415 : if ((tmp = single_set (insn)) != NULL
416 7415 : && SET_DEST (tmp) == pc_rtx
417 7415 : && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
418 7415 : && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
419 0 : mark_tablejump_edge (label_ref_label (XEXP (SET_SRC (tmp), 2)));
420 :
421 89605 : for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
422 : {
423 82190 : if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP)
424 80742 : SET_STATE (e->dest, FULL_STATE (e->dest)
425 : & ~(size_t) BLOCK_USED_BY_TABLEJUMP);
426 1448 : else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
427 : {
428 1448 : remove_edge (e);
429 1448 : continue;
430 : }
431 80742 : ei_next (&ei);
432 : }
433 7415 : }
434 :
435 : /* Scan basic block BB for possible BB boundaries inside the block
436 : and create new basic blocks in the progress. */
437 :
438 : static void
439 27313240 : find_bb_boundaries (basic_block bb)
440 : {
441 27313240 : basic_block orig_bb = bb;
442 27313240 : rtx_insn *insn = BB_HEAD (bb);
443 27313240 : rtx_insn *end = BB_END (bb), *x;
444 27313240 : rtx_jump_table_data *table;
445 27313240 : rtx_insn *flow_transfer_insn = NULL;
446 27313240 : rtx_insn *debug_insn = NULL;
447 27313240 : edge fallthru = NULL;
448 27313240 : bool skip_purge;
449 27313240 : bool seen_note_after_debug = false;
450 :
451 27313240 : if (insn == end)
452 157506 : return;
453 :
454 27167280 : if (DEBUG_INSN_P (insn) || DEBUG_INSN_P (end))
455 : {
456 : /* Check whether, without debug insns, the insn==end test above
457 : would have caused us to return immediately, and behave the
458 : same way even with debug insns. If we don't do this, debug
459 : insns could cause us to purge dead edges at different times,
460 : which could in turn change the cfg and affect codegen
461 : decisions in subtle but undesirable ways. */
462 420786 : while (insn != end && DEBUG_INSN_P (insn))
463 0 : insn = NEXT_INSN (insn);
464 : rtx_insn *e = end;
465 3485120 : while (insn != e && DEBUG_INSN_P (e))
466 3064334 : e = PREV_INSN (e);
467 420786 : if (insn == e)
468 : {
469 : /* If there are debug insns after a single insn that is a
470 : control flow insn in the block, we'd have left right
471 : away, but we should clean up the debug insns after the
472 : control flow insn, because they can't remain in the same
473 : block. So, do the debug insn cleaning up, but then bail
474 : out without purging dead edges as we would if the debug
475 : insns hadn't been there. */
476 11546 : if (e != end && !DEBUG_INSN_P (e) && control_flow_insn_p (e))
477 : {
478 0 : skip_purge = true;
479 0 : flow_transfer_insn = e;
480 0 : goto clean_up_debug_after_control_flow;
481 : }
482 : return;
483 : }
484 : }
485 :
486 27155734 : if (LABEL_P (insn))
487 12759466 : insn = NEXT_INSN (insn);
488 :
489 : /* Scan insn chain and try to find new basic block boundaries. */
490 321995156 : while (1)
491 : {
492 349150890 : enum rtx_code code = GET_CODE (insn);
493 :
494 349150890 : if (code == DEBUG_INSN)
495 : {
496 88949517 : if (flow_transfer_insn && !debug_insn)
497 : {
498 477 : debug_insn = insn;
499 477 : seen_note_after_debug = false;
500 : }
501 : }
502 : /* In case we've previously seen an insn that effects a control
503 : flow transfer, split the block. */
504 260201373 : else if ((flow_transfer_insn || code == CODE_LABEL)
505 260201373 : && inside_basic_block_p (insn))
506 : {
507 2597800 : rtx_insn *prev = PREV_INSN (insn);
508 :
509 : /* If the first non-debug inside_basic_block_p insn after a control
510 : flow transfer is not a label, split the block before the debug
511 : insn instead of before the non-debug insn, so that the debug
512 : insns are not lost. */
513 2597800 : if (debug_insn && code != CODE_LABEL && code != BARRIER)
514 : {
515 477 : prev = PREV_INSN (debug_insn);
516 477 : if (seen_note_after_debug)
517 : {
518 : /* Though, if there are NOTEs intermixed with DEBUG_INSNs,
519 : move the NOTEs before the DEBUG_INSNs and split after
520 : the last NOTE. */
521 : rtx_insn *first = NULL, *last = NULL;
522 0 : for (x = debug_insn; x != insn; x = NEXT_INSN (x))
523 : {
524 0 : if (NOTE_P (x))
525 : {
526 0 : if (first == NULL)
527 0 : first = x;
528 : last = x;
529 : }
530 : else
531 : {
532 0 : gcc_assert (DEBUG_INSN_P (x));
533 0 : if (first)
534 : {
535 0 : reorder_insns_nobb (first, last, prev);
536 0 : prev = last;
537 0 : first = last = NULL;
538 : }
539 : }
540 : }
541 0 : if (first)
542 : {
543 0 : reorder_insns_nobb (first, last, prev);
544 0 : prev = last;
545 : }
546 : }
547 : }
548 2597800 : fallthru = split_block (bb, prev);
549 2597800 : if (flow_transfer_insn)
550 : {
551 2062513 : BB_END (bb) = flow_transfer_insn;
552 :
553 2062513 : rtx_insn *next;
554 : /* Clean up the bb field for the insns between the blocks. */
555 2062513 : for (x = NEXT_INSN (flow_transfer_insn);
556 2548088 : x != BB_HEAD (fallthru->dest);
557 485575 : x = next)
558 : {
559 485575 : next = NEXT_INSN (x);
560 : /* Debug insns should not be in between basic blocks,
561 : drop them on the floor. */
562 485575 : if (DEBUG_INSN_P (x))
563 0 : delete_insn (x);
564 485575 : else if (!BARRIER_P (x))
565 0 : set_block_for_insn (x, NULL);
566 : }
567 : }
568 :
569 2597800 : bb = fallthru->dest;
570 2597800 : remove_edge (fallthru);
571 : /* BB is unreachable at this point - we need to determine its profile
572 : once edges are built. */
573 2597800 : bb->count = profile_count::uninitialized ();
574 2597800 : flow_transfer_insn = NULL;
575 2597800 : debug_insn = NULL;
576 2597800 : if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn))
577 0 : make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
578 : }
579 257603573 : else if (code == BARRIER)
580 : {
581 : /* __builtin_unreachable () may cause a barrier to be emitted in
582 : the middle of a BB. We need to split it in the same manner as
583 : if the barrier were preceded by a control_flow_insn_p insn. */
584 617821 : if (!flow_transfer_insn)
585 0 : flow_transfer_insn = prev_nonnote_nondebug_insn_bb (insn);
586 : debug_insn = NULL;
587 : }
588 256985752 : else if (debug_insn)
589 : {
590 0 : if (code == NOTE)
591 : seen_note_after_debug = true;
592 : else
593 : /* Jump tables. */
594 256985752 : debug_insn = NULL;
595 : }
596 :
597 349150890 : if (control_flow_insn_p (insn))
598 20583923 : flow_transfer_insn = insn;
599 349150890 : if (insn == end)
600 : break;
601 321995156 : insn = NEXT_INSN (insn);
602 321995156 : }
603 :
604 : /* In case expander replaced normal insn by sequence terminating by
605 : return and barrier, or possibly other sequence not behaving like
606 : ordinary jump, we need to take care and move basic block boundary. */
607 27155734 : if (flow_transfer_insn && flow_transfer_insn != end)
608 : {
609 : skip_purge = false;
610 :
611 132246 : clean_up_debug_after_control_flow:
612 132246 : BB_END (bb) = flow_transfer_insn;
613 :
614 : /* Clean up the bb field for the insns that do not belong to BB. */
615 132246 : rtx_insn *next;
616 132246 : for (x = NEXT_INSN (flow_transfer_insn); ; x = next)
617 : {
618 132246 : next = NEXT_INSN (x);
619 : /* Debug insns should not be in between basic blocks,
620 : drop them on the floor. */
621 132246 : if (DEBUG_INSN_P (x))
622 0 : delete_insn (x);
623 132246 : else if (!BARRIER_P (x))
624 0 : set_block_for_insn (x, NULL);
625 132246 : if (x == end)
626 : break;
627 : }
628 :
629 132246 : if (skip_purge)
630 : return;
631 : }
632 :
633 : /* We've possibly replaced the conditional jump by conditional jump
634 : followed by cleanup at fallthru edge, so the outgoing edges may
635 : be dead. */
636 27155734 : purge_dead_edges (bb);
637 :
638 : /* purge_dead_edges doesn't handle tablejump's, but if we have split the
639 : basic block, we might need to kill some edges. */
640 27155734 : if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table))
641 7415 : purge_dead_tablejump_edges (bb, table);
642 : }
643 :
644 : /* Assume that frequency of basic block B is known. Compute frequencies
645 : and probabilities of outgoing edges. */
646 :
647 : static void
648 3257167 : compute_outgoing_frequencies (basic_block b)
649 : {
650 3257167 : edge e, f;
651 3257167 : edge_iterator ei;
652 :
653 3257167 : if (EDGE_COUNT (b->succs) == 2)
654 : {
655 1744040 : rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL);
656 1744040 : int probability;
657 :
658 1744040 : if (note)
659 : {
660 1128363 : probability = XINT (note, 0);
661 1128363 : e = BRANCH_EDGE (b);
662 1128363 : e->probability
663 1128363 : = profile_probability::from_reg_br_prob_note (probability);
664 1128363 : f = FALLTHRU_EDGE (b);
665 1128363 : f->probability = e->probability.invert ();
666 2630487 : return;
667 : }
668 : else
669 : {
670 615677 : guess_outgoing_edge_probabilities (b);
671 : }
672 : }
673 1513127 : else if (single_succ_p (b))
674 : {
675 1502124 : e = single_succ_edge (b);
676 1502124 : e->probability = profile_probability::always ();
677 1502124 : return;
678 : }
679 : else
680 : {
681 : /* We rely on BBs with more than two successors to have sane probabilities
682 : and do not guess them here. For BBs terminated by switch statements
683 : expanded to jump-table jump, we have done the right thing during
684 : expansion. For EH edges, we still guess the probabilities here. */
685 11003 : bool complex_edge = false;
686 91804 : FOR_EACH_EDGE (e, ei, b->succs)
687 81879 : if (e->flags & EDGE_COMPLEX)
688 : {
689 : complex_edge = true;
690 : break;
691 : }
692 11003 : if (complex_edge)
693 1078 : guess_outgoing_edge_probabilities (b);
694 : }
695 : }
696 :
697 : /* Update the profile information for BB, which was created by splitting
698 : an RTL block that had a non-final jump. */
699 :
700 : static void
701 2205415 : update_profile_for_new_sub_basic_block (basic_block bb)
702 : {
703 2205415 : edge e;
704 2205415 : edge_iterator ei;
705 :
706 2205415 : bool initialized_src = false, uninitialized_src = false;
707 2205415 : bb->count = profile_count::zero ();
708 5037579 : FOR_EACH_EDGE (e, ei, bb->preds)
709 : {
710 2832164 : if (e->count ().initialized_p ())
711 : {
712 2799429 : bb->count += e->count ();
713 2799429 : initialized_src = true;
714 : }
715 : else
716 : uninitialized_src = true;
717 : }
718 : /* When some edges are missing with read profile, this is
719 : most likely because RTL expansion introduced loop.
720 : When profile is guessed we may have BB that is reachable
721 : from unlikely path as well as from normal path.
722 :
723 : TODO: We should handle loops created during BB expansion
724 : correctly here. For now we assume all those loop to cycle
725 : precisely once. */
726 2205415 : if (!initialized_src
727 2189892 : || (uninitialized_src
728 28496 : && profile_status_for_fn (cfun) < PROFILE_GUESSED))
729 15523 : bb->count = profile_count::uninitialized ();
730 :
731 2205415 : compute_outgoing_frequencies (bb);
732 2205415 : }
733 :
734 : /* Assume that some pass has inserted labels or control flow
735 : instructions within a basic block. Split basic blocks as needed
736 : and create edges. */
737 :
738 : void
739 3747267 : find_many_sub_basic_blocks (sbitmap blocks)
740 : {
741 3747267 : basic_block bb, min, max;
742 3747267 : bool found = false;
743 3747267 : auto_vec<unsigned int> n_succs;
744 3747267 : n_succs.safe_grow_cleared (last_basic_block_for_fn (cfun), true);
745 :
746 60458811 : FOR_EACH_BB_FN (bb, cfun)
747 89195691 : SET_STATE (bb,
748 : bitmap_bit_p (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL);
749 :
750 62536615 : FOR_EACH_BB_FN (bb, cfun)
751 58789348 : if (STATE (bb) == BLOCK_TO_SPLIT)
752 : {
753 24227397 : int n = last_basic_block_for_fn (cfun);
754 24227397 : unsigned int ns = EDGE_COUNT (bb->succs);
755 :
756 24227397 : find_bb_boundaries (bb);
757 47316282 : if (n == last_basic_block_for_fn (cfun) && ns == EDGE_COUNT (bb->succs))
758 23295835 : n_succs[bb->index] = EDGE_COUNT (bb->succs);
759 : }
760 :
761 8649894 : FOR_EACH_BB_FN (bb, cfun)
762 8649894 : if (STATE (bb) != BLOCK_ORIGINAL)
763 : {
764 : found = true;
765 : break;
766 : }
767 :
768 3747267 : if (!found)
769 0 : return;
770 :
771 : min = max = bb;
772 57633988 : for (; bb != EXIT_BLOCK_PTR_FOR_FN (cfun); bb = bb->next_bb)
773 53886721 : if (STATE (bb) != BLOCK_ORIGINAL)
774 26305201 : max = bb;
775 :
776 : /* Now re-scan and wire in all edges. This expect simple (conditional)
777 : jumps at the end of each new basic blocks. */
778 3747267 : make_edges (min, max, 1);
779 :
780 : /* Update branch probabilities. Expect only (un)conditional jumps
781 : to be created with only the forward edges. */
782 3747267 : if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
783 31299859 : FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
784 : {
785 28659540 : if (STATE (bb) == BLOCK_ORIGINAL)
786 8185422 : continue;
787 20474118 : if (STATE (bb) == BLOCK_NEW)
788 : {
789 1716153 : update_profile_for_new_sub_basic_block (bb);
790 1716153 : continue;
791 : }
792 : /* If nothing changed, there is no need to create new BBs. */
793 37498505 : if (EDGE_COUNT (bb->succs) == n_succs[bb->index])
794 : {
795 : /* In rare occasions RTL expansion might have mistakely assigned
796 : a probabilities different from what is in CFG. This happens
797 : when we try to split branch to two but optimize out the
798 : second branch during the way. See PR81030. */
799 10437268 : if (JUMP_P (BB_END (bb)) && any_condjump_p (BB_END (bb))
800 24748491 : && EDGE_COUNT (bb->succs) >= 2)
801 6797651 : update_br_prob_note (bb);
802 17950840 : continue;
803 : }
804 807125 : compute_outgoing_frequencies (bb);
805 : }
806 :
807 62536615 : FOR_EACH_BB_FN (bb, cfun)
808 58789348 : SET_STATE (bb, 0);
809 3747267 : }
810 :
811 : /* Like find_many_sub_basic_blocks, but look only within BB. */
812 :
813 : void
814 3085843 : find_sub_basic_blocks (basic_block bb)
815 : {
816 3085843 : basic_block end_bb = bb->next_bb;
817 3085843 : find_bb_boundaries (bb);
818 3085843 : if (bb->next_bb == end_bb)
819 : return;
820 :
821 : /* Re-scan and wire in all edges. This expects simple (conditional)
822 : jumps at the end of each new basic blocks. */
823 259992 : make_edges (bb, end_bb->prev_bb, 1);
824 :
825 : /* Update branch probabilities. Expect only (un)conditional jumps
826 : to be created with only the forward edges. */
827 259992 : if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
828 : {
829 244627 : compute_outgoing_frequencies (bb);
830 733889 : for (bb = bb->next_bb; bb != end_bb; bb = bb->next_bb)
831 489262 : update_profile_for_new_sub_basic_block (bb);
832 : }
833 : }
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