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 192613523 : inside_basic_block_p (const rtx_insn *insn)
45 : {
46 192613523 : switch (GET_CODE (insn))
47 : {
48 11541213 : case CODE_LABEL:
49 : /* Avoid creating of basic block for jumptables. */
50 11541213 : return (NEXT_INSN (insn) == 0
51 11541213 : || ! 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 10749545434 : control_flow_insn_p (const rtx_insn *insn)
74 : {
75 10749545434 : 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 390176036 : case CALL_INSN:
86 : /* Noreturn and sibling call instructions terminate the basic blocks
87 : (but only if they happen unconditionally). */
88 390176036 : if ((SIBLING_CALL_P (insn)
89 389242870 : || find_reg_note (insn, REG_NORETURN, 0))
90 393352907 : && GET_CODE (PATTERN (insn)) != COND_EXEC)
91 : return true;
92 :
93 : /* Call insn may return to the nonlocal goto handler. */
94 386065999 : if (can_nonlocal_goto (insn))
95 : return true;
96 : break;
97 :
98 5265297085 : case INSN:
99 : /* Treat trap instructions like noreturn calls (same provision). */
100 5265297085 : if (GET_CODE (PATTERN (insn)) == TRAP_IF
101 5265297085 : && XEXP (PATTERN (insn), 0) == const1_rtx)
102 : return true;
103 5265216703 : 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 1737799245 : 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 15983922 : make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags)
129 : {
130 15983922 : 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 15983922 : if (INSN_UID (label) == 0)
138 : return;
139 :
140 15983922 : 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 9763630 : rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn)
147 : {
148 9763630 : eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn);
149 :
150 9763630 : if (lp)
151 : {
152 1224834 : rtx_insn *label = lp->landing_pad;
153 :
154 : /* During initial rtl generation, use the post_landing_pad. */
155 1224834 : if (label == NULL)
156 : {
157 702102 : gcc_assert (lp->post_landing_pad);
158 702102 : label = label_rtx (lp->post_landing_pad);
159 : }
160 :
161 1224834 : make_label_edge (edge_cache, src, label,
162 : EDGE_ABNORMAL | EDGE_EH
163 1224834 : | (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0));
164 : }
165 9763630 : }
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 3904577 : make_edges (basic_block min, basic_block max, int update_p)
201 : {
202 3904577 : basic_block bb;
203 3904577 : 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 3904577 : if (!vec_safe_is_empty (forced_labels)
209 3859043 : || cfun->cfg->max_jumptable_ents > 100)
210 46002 : 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 3904577 : if (min == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb)
215 3431314 : make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), min, EDGE_FALLTHRU);
216 :
217 39446559 : FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
218 : {
219 35541982 : rtx_insn *insn;
220 35541982 : enum rtx_code code;
221 35541982 : edge e;
222 35541982 : edge_iterator ei;
223 :
224 35541982 : if (STATE (bb) == BLOCK_ORIGINAL)
225 9066896 : continue;
226 :
227 : /* If we have an edge cache, cache edges going out of BB. */
228 26475086 : if (edge_cache)
229 : {
230 227299 : bitmap_clear (edge_cache);
231 227299 : if (update_p)
232 : {
233 517872 : FOR_EACH_EDGE (e, ei, bb->succs)
234 290573 : if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
235 267585 : bitmap_set_bit (edge_cache, e->dest->index);
236 : }
237 : }
238 :
239 26475086 : if (LABEL_P (BB_HEAD (bb))
240 26475086 : && 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 26475086 : insn = BB_END (bb);
247 26475086 : code = GET_CODE (insn);
248 :
249 : /* A branch. */
250 26475086 : if (code == JUMP_INSN)
251 : {
252 15065280 : rtx tmp;
253 15065280 : rtx_jump_table_data *table;
254 :
255 : /* Recognize a non-local goto as a branch outside the
256 : current function. */
257 15065280 : if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
258 : ;
259 :
260 : /* Recognize a tablejump and do the right thing. */
261 15063846 : else if (tablejump_p (insn, NULL, &table))
262 : {
263 9753 : rtvec vec = table->get_labels ();
264 9753 : int j;
265 :
266 207176 : for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
267 197423 : make_label_edge (edge_cache, bb,
268 197423 : XEXP (RTVEC_ELT (vec, j), 0), 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 9753 : if ((tmp = single_set (insn)) != NULL
274 9753 : && SET_DEST (tmp) == pc_rtx
275 9753 : && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
276 9753 : && 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 15054093 : else if (computed_jump_p (insn))
284 : {
285 : rtx_insn *insn;
286 : unsigned int i;
287 15066996 : FOR_EACH_VEC_SAFE_ELT (forced_labels, i, insn)
288 1318 : make_label_edge (edge_cache, bb, insn, EDGE_ABNORMAL);
289 : }
290 :
291 : /* Returns create an exit out. */
292 15053630 : else if (returnjump_p (insn))
293 561931 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0);
294 :
295 : /* Recognize asm goto and do the right thing. */
296 14491699 : else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
297 : {
298 672 : int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
299 1703 : for (i = 0; i < n; ++i)
300 1031 : make_label_edge (edge_cache, bb,
301 1031 : XEXP (ASM_OPERANDS_LABEL (tmp, i), 0), 0);
302 : }
303 :
304 : /* Otherwise, we have a plain conditional or unconditional jump. */
305 : else
306 : {
307 14491027 : gcc_assert (JUMP_LABEL (insn));
308 14491027 : make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
309 : }
310 : }
311 :
312 : /* If this is a sibling call insn, then this is in effect a combined call
313 : and return, and so we need an edge to the exit block. No need to
314 : worry about EH edges, since we wouldn't have created the sibling call
315 : in the first place. */
316 26475086 : if (code == CALL_INSN && SIBLING_CALL_P (insn))
317 158870 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
318 : EDGE_SIBCALL | EDGE_ABNORMAL);
319 :
320 : /* If this is a CALL_INSN, then mark it as reaching the active EH
321 : handler for this CALL_INSN. If we're handling non-call
322 : exceptions then any insn can reach any of the active handlers.
323 : Also mark the CALL_INSN as reaching any nonlocal goto handler. */
324 26316216 : else if (code == CALL_INSN || cfun->can_throw_non_call_exceptions)
325 : {
326 : /* Add any appropriate EH edges. */
327 9753644 : rtl_make_eh_edge (edge_cache, bb, insn);
328 :
329 9753644 : if (code == CALL_INSN)
330 : {
331 2474608 : if (can_nonlocal_goto (insn))
332 : {
333 : /* ??? This could be made smarter: in some cases it's
334 : possible to tell that certain calls will not do a
335 : nonlocal goto. For example, if the nested functions
336 : that do the nonlocal gotos do not have their addresses
337 : taken, then only calls to those functions or to other
338 : nested functions that use them could possibly do
339 : nonlocal gotos. */
340 72710 : for (rtx_insn_list *x = nonlocal_goto_handler_labels;
341 72710 : x;
342 68289 : x = x->next ())
343 68289 : make_label_edge (edge_cache, bb, x->insn (),
344 : EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
345 : }
346 :
347 2474608 : if (flag_tm)
348 : {
349 1520 : rtx note;
350 4992 : for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
351 3472 : if (REG_NOTE_KIND (note) == REG_TM)
352 0 : make_label_edge (edge_cache, bb, XEXP (note, 0),
353 : EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
354 : }
355 : }
356 : }
357 :
358 : /* Find out if we can drop through to the next block. */
359 26475086 : insn = NEXT_INSN (insn);
360 26475086 : e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun));
361 26475086 : if (e && e->flags & EDGE_FALLTHRU)
362 26475086 : insn = NULL;
363 :
364 : while (insn
365 24610031 : && NOTE_P (insn)
366 38649385 : && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK)
367 3757 : insn = NEXT_INSN (insn);
368 :
369 26475086 : if (!insn)
370 1868812 : cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
371 : EDGE_FALLTHRU);
372 24606274 : else if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
373 : {
374 23998816 : if (insn == BB_HEAD (bb->next_bb))
375 18341256 : cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU);
376 : }
377 : }
378 :
379 3904577 : if (edge_cache)
380 46002 : sbitmap_free (edge_cache);
381 3904577 : }
382 :
383 : static void
384 126873 : mark_tablejump_edge (rtx label)
385 : {
386 126873 : basic_block bb;
387 :
388 126873 : gcc_assert (LABEL_P (label));
389 : /* See comment in make_label_edge. */
390 126873 : if (INSN_UID (label) == 0)
391 : return;
392 126873 : bb = BLOCK_FOR_INSN (label);
393 126873 : SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP);
394 : }
395 :
396 : static void
397 4725 : purge_dead_tablejump_edges (basic_block bb, rtx_jump_table_data *table)
398 : {
399 4725 : rtx_insn *insn = BB_END (bb);
400 4725 : rtx tmp;
401 4725 : rtvec vec;
402 4725 : int j;
403 4725 : edge_iterator ei;
404 4725 : edge e;
405 :
406 4725 : vec = table->get_labels ();
407 :
408 131598 : for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
409 126873 : mark_tablejump_edge (XEXP (RTVEC_ELT (vec, j), 0));
410 :
411 : /* Some targets (eg, ARM) emit a conditional jump that also
412 : contains the out-of-range target. Scan for these and
413 : add an edge if necessary. */
414 4725 : if ((tmp = single_set (insn)) != NULL
415 4725 : && SET_DEST (tmp) == pc_rtx
416 4725 : && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
417 4725 : && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
418 0 : mark_tablejump_edge (label_ref_label (XEXP (SET_SRC (tmp), 2)));
419 :
420 57557 : for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
421 : {
422 52832 : if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP)
423 51799 : SET_STATE (e->dest, FULL_STATE (e->dest)
424 : & ~(size_t) BLOCK_USED_BY_TABLEJUMP);
425 1033 : else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
426 : {
427 1033 : remove_edge (e);
428 1033 : continue;
429 : }
430 51799 : ei_next (&ei);
431 : }
432 4725 : }
433 :
434 : /* Scan basic block BB for possible BB boundaries inside the block
435 : and create new basic blocks in the progress. */
436 :
437 : static void
438 26659625 : find_bb_boundaries (basic_block bb)
439 : {
440 26659625 : basic_block orig_bb = bb;
441 26659625 : rtx_insn *insn = BB_HEAD (bb);
442 26659625 : rtx_insn *end = BB_END (bb), *x;
443 26659625 : rtx_jump_table_data *table;
444 26659625 : rtx_insn *flow_transfer_insn = NULL;
445 26659625 : rtx_insn *debug_insn = NULL;
446 26659625 : edge fallthru = NULL;
447 26659625 : bool skip_purge;
448 26659625 : bool seen_note_after_debug = false;
449 :
450 26659625 : if (insn == end)
451 151883 : return;
452 :
453 26519399 : if (DEBUG_INSN_P (insn) || DEBUG_INSN_P (end))
454 : {
455 : /* Check whether, without debug insns, the insn==end test above
456 : would have caused us to return immediately, and behave the
457 : same way even with debug insns. If we don't do this, debug
458 : insns could cause us to purge dead edges at different times,
459 : which could in turn change the cfg and affect codegen
460 : decisions in subtle but undesirable ways. */
461 388111 : while (insn != end && DEBUG_INSN_P (insn))
462 0 : insn = NEXT_INSN (insn);
463 : rtx_insn *e = end;
464 3093854 : while (insn != e && DEBUG_INSN_P (e))
465 2705743 : e = PREV_INSN (e);
466 388111 : if (insn == e)
467 : {
468 : /* If there are debug insns after a single insn that is a
469 : control flow insn in the block, we'd have left right
470 : away, but we should clean up the debug insns after the
471 : control flow insn, because they can't remain in the same
472 : block. So, do the debug insn cleaning up, but then bail
473 : out without purging dead edges as we would if the debug
474 : insns hadn't been there. */
475 11657 : if (e != end && !DEBUG_INSN_P (e) && control_flow_insn_p (e))
476 : {
477 0 : skip_purge = true;
478 0 : flow_transfer_insn = e;
479 0 : goto clean_up_debug_after_control_flow;
480 : }
481 11657 : return;
482 : }
483 : }
484 :
485 26507742 : if (LABEL_P (insn))
486 12483229 : insn = NEXT_INSN (insn);
487 :
488 : /* Scan insn chain and try to find new basic block boundaries. */
489 307079094 : while (1)
490 : {
491 333586836 : enum rtx_code code = GET_CODE (insn);
492 :
493 333586836 : if (code == DEBUG_INSN)
494 : {
495 80018425 : if (flow_transfer_insn && !debug_insn)
496 : {
497 477 : debug_insn = insn;
498 477 : seen_note_after_debug = false;
499 : }
500 : }
501 : /* In case we've previously seen an insn that effects a control
502 : flow transfer, split the block. */
503 253568411 : else if ((flow_transfer_insn || code == CODE_LABEL)
504 253568411 : && inside_basic_block_p (insn))
505 : {
506 2557799 : rtx_insn *prev = PREV_INSN (insn);
507 :
508 : /* If the first non-debug inside_basic_block_p insn after a control
509 : flow transfer is not a label, split the block before the debug
510 : insn instead of before the non-debug insn, so that the debug
511 : insns are not lost. */
512 2557799 : if (debug_insn && code != CODE_LABEL && code != BARRIER)
513 : {
514 477 : prev = PREV_INSN (debug_insn);
515 477 : if (seen_note_after_debug)
516 : {
517 : /* Though, if there are NOTEs intermixed with DEBUG_INSNs,
518 : move the NOTEs before the DEBUG_INSNs and split after
519 : the last NOTE. */
520 : rtx_insn *first = NULL, *last = NULL;
521 0 : for (x = debug_insn; x != insn; x = NEXT_INSN (x))
522 : {
523 0 : if (NOTE_P (x))
524 : {
525 0 : if (first == NULL)
526 0 : first = x;
527 : last = x;
528 : }
529 : else
530 : {
531 0 : gcc_assert (DEBUG_INSN_P (x));
532 0 : if (first)
533 : {
534 0 : reorder_insns_nobb (first, last, prev);
535 0 : prev = last;
536 0 : first = last = NULL;
537 : }
538 : }
539 : }
540 0 : if (first)
541 : {
542 0 : reorder_insns_nobb (first, last, prev);
543 0 : prev = last;
544 : }
545 : }
546 : }
547 2557799 : fallthru = split_block (bb, prev);
548 2557799 : if (flow_transfer_insn)
549 : {
550 1998037 : BB_END (bb) = flow_transfer_insn;
551 :
552 1998037 : rtx_insn *next;
553 : /* Clean up the bb field for the insns between the blocks. */
554 1998037 : for (x = NEXT_INSN (flow_transfer_insn);
555 2461377 : x != BB_HEAD (fallthru->dest);
556 : x = next)
557 : {
558 463340 : next = NEXT_INSN (x);
559 : /* Debug insns should not be in between basic blocks,
560 : drop them on the floor. */
561 463340 : if (DEBUG_INSN_P (x))
562 0 : delete_insn (x);
563 463340 : else if (!BARRIER_P (x))
564 0 : set_block_for_insn (x, NULL);
565 : }
566 : }
567 :
568 2557799 : bb = fallthru->dest;
569 2557799 : remove_edge (fallthru);
570 : /* BB is unreachable at this point - we need to determine its profile
571 : once edges are built. */
572 2557799 : bb->count = profile_count::uninitialized ();
573 2557799 : flow_transfer_insn = NULL;
574 2557799 : debug_insn = NULL;
575 2557799 : if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn))
576 0 : make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
577 : }
578 251010612 : else if (code == BARRIER)
579 : {
580 : /* __builtin_unreachable () may cause a barrier to be emitted in
581 : the middle of a BB. We need to split it in the same manner as
582 : if the barrier were preceded by a control_flow_insn_p insn. */
583 592686 : if (!flow_transfer_insn)
584 0 : flow_transfer_insn = prev_nonnote_nondebug_insn_bb (insn);
585 : debug_insn = NULL;
586 : }
587 250417926 : else if (debug_insn)
588 : {
589 0 : if (code == NOTE)
590 : seen_note_after_debug = true;
591 : else
592 : /* Jump tables. */
593 250417926 : debug_insn = NULL;
594 : }
595 :
596 333586836 : if (control_flow_insn_p (insn))
597 20145145 : flow_transfer_insn = insn;
598 333586836 : if (insn == end)
599 : break;
600 307079094 : insn = NEXT_INSN (insn);
601 307079094 : }
602 :
603 : /* In case expander replaced normal insn by sequence terminating by
604 : return and barrier, or possibly other sequence not behaving like
605 : ordinary jump, we need to take care and move basic block boundary. */
606 26507742 : if (flow_transfer_insn && flow_transfer_insn != end)
607 : {
608 : skip_purge = false;
609 :
610 129346 : clean_up_debug_after_control_flow:
611 129346 : BB_END (bb) = flow_transfer_insn;
612 :
613 : /* Clean up the bb field for the insns that do not belong to BB. */
614 129346 : rtx_insn *next;
615 129346 : for (x = NEXT_INSN (flow_transfer_insn); ; x = next)
616 : {
617 129346 : next = NEXT_INSN (x);
618 : /* Debug insns should not be in between basic blocks,
619 : drop them on the floor. */
620 129346 : if (DEBUG_INSN_P (x))
621 0 : delete_insn (x);
622 129346 : else if (!BARRIER_P (x))
623 0 : set_block_for_insn (x, NULL);
624 129346 : if (x == end)
625 : break;
626 : }
627 :
628 129346 : if (skip_purge)
629 : return;
630 : }
631 :
632 : /* We've possibly replaced the conditional jump by conditional jump
633 : followed by cleanup at fallthru edge, so the outgoing edges may
634 : be dead. */
635 26507742 : purge_dead_edges (bb);
636 :
637 : /* purge_dead_edges doesn't handle tablejump's, but if we have split the
638 : basic block, we might need to kill some edges. */
639 26507742 : if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table))
640 4725 : purge_dead_tablejump_edges (bb, table);
641 : }
642 :
643 : /* Assume that frequency of basic block B is known. Compute frequencies
644 : and probabilities of outgoing edges. */
645 :
646 : static void
647 3160747 : compute_outgoing_frequencies (basic_block b)
648 : {
649 3160747 : edge e, f;
650 3160747 : edge_iterator ei;
651 :
652 3160747 : if (EDGE_COUNT (b->succs) == 2)
653 : {
654 1695507 : rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL);
655 1695507 : int probability;
656 :
657 1695507 : if (note)
658 : {
659 1130388 : probability = XINT (note, 0);
660 1130388 : e = BRANCH_EDGE (b);
661 1130388 : e->probability
662 1130388 : = profile_probability::from_reg_br_prob_note (probability);
663 1130388 : f = FALLTHRU_EDGE (b);
664 1130388 : f->probability = e->probability.invert ();
665 2587224 : return;
666 : }
667 : else
668 : {
669 565119 : guess_outgoing_edge_probabilities (b);
670 : }
671 : }
672 1465240 : else if (single_succ_p (b))
673 : {
674 1456836 : e = single_succ_edge (b);
675 1456836 : e->probability = profile_probability::always ();
676 1456836 : return;
677 : }
678 : else
679 : {
680 : /* We rely on BBs with more than two successors to have sane probabilities
681 : and do not guess them here. For BBs terminated by switch statements
682 : expanded to jump-table jump, we have done the right thing during
683 : expansion. For EH edges, we still guess the probabilities here. */
684 8404 : bool complex_edge = false;
685 60360 : FOR_EACH_EDGE (e, ei, b->succs)
686 53033 : if (e->flags & EDGE_COMPLEX)
687 : {
688 : complex_edge = true;
689 : break;
690 : }
691 8404 : if (complex_edge)
692 1077 : guess_outgoing_edge_probabilities (b);
693 : }
694 : }
695 :
696 : /* Update the profile information for BB, which was created by splitting
697 : an RTL block that had a non-final jump. */
698 :
699 : static void
700 2163102 : update_profile_for_new_sub_basic_block (basic_block bb)
701 : {
702 2163102 : edge e;
703 2163102 : edge_iterator ei;
704 :
705 2163102 : bool initialized_src = false, uninitialized_src = false;
706 2163102 : bb->count = profile_count::zero ();
707 4964942 : FOR_EACH_EDGE (e, ei, bb->preds)
708 : {
709 2801840 : if (e->count ().initialized_p ())
710 : {
711 2767644 : bb->count += e->count ();
712 2767644 : initialized_src = true;
713 : }
714 : else
715 : uninitialized_src = true;
716 : }
717 : /* When some edges are missing with read profile, this is
718 : most likely because RTL expansion introduced loop.
719 : When profile is guessed we may have BB that is reachable
720 : from unlikely path as well as from normal path.
721 :
722 : TODO: We should handle loops created during BB expansion
723 : correctly here. For now we assume all those loop to cycle
724 : precisely once. */
725 2163102 : if (!initialized_src
726 2156031 : || (uninitialized_src
727 30060 : && profile_status_for_fn (cfun) < PROFILE_GUESSED))
728 7071 : bb->count = profile_count::uninitialized ();
729 :
730 2163102 : compute_outgoing_frequencies (bb);
731 2163102 : }
732 :
733 : /* Assume that some pass has inserted labels or control flow
734 : instructions within a basic block. Split basic blocks as needed
735 : and create edges. */
736 :
737 : void
738 3644649 : find_many_sub_basic_blocks (sbitmap blocks)
739 : {
740 3644649 : basic_block bb, min, max;
741 3644649 : bool found = false;
742 3644649 : auto_vec<unsigned int> n_succs;
743 3644649 : n_succs.safe_grow_cleared (last_basic_block_for_fn (cfun), true);
744 :
745 58700042 : FOR_EACH_BB_FN (bb, cfun)
746 86453427 : SET_STATE (bb,
747 : bitmap_bit_p (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL);
748 :
749 60737973 : FOR_EACH_BB_FN (bb, cfun)
750 57093324 : if (STATE (bb) == BLOCK_TO_SPLIT)
751 : {
752 23657359 : int n = last_basic_block_for_fn (cfun);
753 23657359 : unsigned int ns = EDGE_COUNT (bb->succs);
754 :
755 23657359 : find_bb_boundaries (bb);
756 46244081 : if (n == last_basic_block_for_fn (cfun) && ns == EDGE_COUNT (bb->succs))
757 22779875 : n_succs[bb->index] = EDGE_COUNT (bb->succs);
758 : }
759 :
760 8323699 : FOR_EACH_BB_FN (bb, cfun)
761 8323699 : if (STATE (bb) != BLOCK_ORIGINAL)
762 : {
763 : found = true;
764 : break;
765 : }
766 :
767 3644649 : if (!found)
768 0 : return;
769 :
770 : min = max = bb;
771 56058923 : for (; bb != EXIT_BLOCK_PTR_FOR_FN (cfun); bb = bb->next_bb)
772 52414274 : if (STATE (bb) != BLOCK_ORIGINAL)
773 25695290 : max = bb;
774 :
775 : /* Now re-scan and wire in all edges. This expect simple (conditional)
776 : jumps at the end of each new basic blocks. */
777 3644649 : make_edges (min, max, 1);
778 :
779 : /* Update branch probabilities. Expect only (un)conditional jumps
780 : to be created with only the forward edges. */
781 3644649 : if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
782 30553686 : FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
783 : {
784 27970750 : if (STATE (bb) == BLOCK_ORIGINAL)
785 7941549 : continue;
786 20029201 : if (STATE (bb) == BLOCK_NEW)
787 : {
788 1673964 : update_profile_for_new_sub_basic_block (bb);
789 1673964 : continue;
790 : }
791 : /* If nothing changed, there is no need to create new BBs. */
792 36699034 : if (EDGE_COUNT (bb->succs) == n_succs[bb->index])
793 : {
794 : /* In rare occassions RTL expansion might have mistakely assigned
795 : a probabilities different from what is in CFG. This happens
796 : when we try to split branch to two but optimize out the
797 : second branch during the way. See PR81030. */
798 10334021 : if (JUMP_P (BB_END (bb)) && any_condjump_p (BB_END (bb))
799 24377901 : && EDGE_COUNT (bb->succs) >= 2)
800 6775744 : update_br_prob_note (bb);
801 17602157 : continue;
802 : }
803 753080 : compute_outgoing_frequencies (bb);
804 : }
805 :
806 60737973 : FOR_EACH_BB_FN (bb, cfun)
807 57093324 : SET_STATE (bb, 0);
808 3644649 : }
809 :
810 : /* Like find_many_sub_basic_blocks, but look only within BB. */
811 :
812 : void
813 3002266 : find_sub_basic_blocks (basic_block bb)
814 : {
815 3002266 : basic_block end_bb = bb->next_bb;
816 3002266 : find_bb_boundaries (bb);
817 3002266 : if (bb->next_bb == end_bb)
818 : return;
819 :
820 : /* Re-scan and wire in all edges. This expects simple (conditional)
821 : jumps at the end of each new basic blocks. */
822 259928 : make_edges (bb, end_bb->prev_bb, 1);
823 :
824 : /* Update branch probabilities. Expect only (un)conditional jumps
825 : to be created with only the forward edges. */
826 259928 : if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
827 : {
828 244565 : compute_outgoing_frequencies (bb);
829 733703 : for (bb = bb->next_bb; bb != end_bb; bb = bb->next_bb)
830 489138 : update_profile_for_new_sub_basic_block (bb);
831 : }
832 : }
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