1/* Iterator routines for GIMPLE statements.
2 Copyright (C) 2007-2017 Free Software Foundation, Inc.
3 Contributed by Aldy Hernandez <aldy@quesejoda.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3. If not see
19<http://www.gnu.org/licenses/>. */
20
21#include "config.h"
22#include "system.h"
23#include "coretypes.h"
24#include "backend.h"
25#include "tree.h"
26#include "gimple.h"
27#include "cfghooks.h"
28#include "ssa.h"
29#include "cgraph.h"
30#include "tree-eh.h"
31#include "gimple-iterator.h"
32#include "tree-cfg.h"
33#include "tree-ssa.h"
34#include "value-prof.h"
35
36
37/* Mark the statement STMT as modified, and update it. */
38
39static inline void
40update_modified_stmt (gimple *stmt)
41{
42 if (!ssa_operands_active (cfun))
43 return;
44 update_stmt_if_modified (stmt);
45}
46
47
48/* Mark the statements in SEQ as modified, and update them. */
49
50void
51update_modified_stmts (gimple_seq seq)
52{
53 gimple_stmt_iterator gsi;
54
55 if (!ssa_operands_active (cfun))
56 return;
57 for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
58 update_stmt_if_modified (gsi_stmt (gsi));
59}
60
61
62/* Set BB to be the basic block for all the statements in the list
63 starting at FIRST and LAST. */
64
65static void
66update_bb_for_stmts (gimple_seq_node first, gimple_seq_node last,
67 basic_block bb)
68{
69 gimple_seq_node n;
70
71 for (n = first; n; n = n->next)
72 {
73 gimple_set_bb (n, bb);
74 if (n == last)
75 break;
76 }
77}
78
79/* Set the frequencies for the cgraph_edges for each of the calls
80 starting at FIRST for their new position within BB. */
81
82static void
83update_call_edge_frequencies (gimple_seq_node first, basic_block bb)
84{
85 struct cgraph_node *cfun_node = NULL;
86 gimple_seq_node n;
87
88 for (n = first; n ; n = n->next)
89 if (is_gimple_call (n))
90 {
91 struct cgraph_edge *e;
92
93 /* These function calls are expensive enough that we want
94 to avoid calling them if we never see any calls. */
95 if (cfun_node == NULL)
96 cfun_node = cgraph_node::get (current_function_decl);
97
98 e = cfun_node->get_edge (n);
99 if (e != NULL)
100 e->count = bb->count;
101 }
102}
103
104/* Insert the sequence delimited by nodes FIRST and LAST before
105 iterator I. M specifies how to update iterator I after insertion
106 (see enum gsi_iterator_update).
107
108 This routine assumes that there is a forward and backward path
109 between FIRST and LAST (i.e., they are linked in a doubly-linked
110 list). Additionally, if FIRST == LAST, this routine will properly
111 insert a single node. */
112
113static void
114gsi_insert_seq_nodes_before (gimple_stmt_iterator *i,
115 gimple_seq_node first,
116 gimple_seq_node last,
117 enum gsi_iterator_update mode)
118{
119 basic_block bb;
120 gimple_seq_node cur = i->ptr;
121
122 gcc_assert (!cur || cur->prev);
123
124 if ((bb = gsi_bb (*i)) != NULL)
125 update_bb_for_stmts (first, last, bb);
126
127 /* Link SEQ before CUR in the sequence. */
128 if (cur)
129 {
130 first->prev = cur->prev;
131 if (first->prev->next)
132 first->prev->next = first;
133 else
134 gimple_seq_set_first (i->seq, first);
135 last->next = cur;
136 cur->prev = last;
137 }
138 else
139 {
140 gimple_seq_node itlast = gimple_seq_last (*i->seq);
141
142 /* If CUR is NULL, we link at the end of the sequence (this case happens
143 when gsi_after_labels is called for a basic block that contains only
144 labels, so it returns an iterator after the end of the block, and
145 we need to insert before it; it might be cleaner to add a flag to the
146 iterator saying whether we are at the start or end of the list). */
147 last->next = NULL;
148 if (itlast)
149 {
150 first->prev = itlast;
151 itlast->next = first;
152 }
153 else
154 gimple_seq_set_first (i->seq, first);
155 gimple_seq_set_last (i->seq, last);
156 }
157
158 /* Update the iterator, if requested. */
159 switch (mode)
160 {
161 case GSI_NEW_STMT:
162 case GSI_CONTINUE_LINKING:
163 i->ptr = first;
164 break;
165 case GSI_SAME_STMT:
166 break;
167 default:
168 gcc_unreachable ();
169 }
170}
171
172
173/* Inserts the sequence of statements SEQ before the statement pointed
174 by iterator I. MODE indicates what to do with the iterator after
175 insertion (see enum gsi_iterator_update).
176
177 This function does not scan for new operands. It is provided for
178 the use of the gimplifier, which manipulates statements for which
179 def/use information has not yet been constructed. Most callers
180 should use gsi_insert_seq_before. */
181
182void
183gsi_insert_seq_before_without_update (gimple_stmt_iterator *i, gimple_seq seq,
184 enum gsi_iterator_update mode)
185{
186 gimple_seq_node first, last;
187
188 if (seq == NULL)
189 return;
190
191 /* Don't allow inserting a sequence into itself. */
192 gcc_assert (seq != *i->seq);
193
194 first = gimple_seq_first (seq);
195 last = gimple_seq_last (seq);
196
197 /* Empty sequences need no work. */
198 if (!first || !last)
199 {
200 gcc_assert (first == last);
201 return;
202 }
203
204 gsi_insert_seq_nodes_before (i, first, last, mode);
205}
206
207
208/* Inserts the sequence of statements SEQ before the statement pointed
209 by iterator I. MODE indicates what to do with the iterator after
210 insertion (see enum gsi_iterator_update). Scan the statements in SEQ
211 for new operands. */
212
213void
214gsi_insert_seq_before (gimple_stmt_iterator *i, gimple_seq seq,
215 enum gsi_iterator_update mode)
216{
217 update_modified_stmts (seq);
218 gsi_insert_seq_before_without_update (i, seq, mode);
219}
220
221
222/* Insert the sequence delimited by nodes FIRST and LAST after
223 iterator I. M specifies how to update iterator I after insertion
224 (see enum gsi_iterator_update).
225
226 This routine assumes that there is a forward and backward path
227 between FIRST and LAST (i.e., they are linked in a doubly-linked
228 list). Additionally, if FIRST == LAST, this routine will properly
229 insert a single node. */
230
231static void
232gsi_insert_seq_nodes_after (gimple_stmt_iterator *i,
233 gimple_seq_node first,
234 gimple_seq_node last,
235 enum gsi_iterator_update m)
236{
237 basic_block bb;
238 gimple_seq_node cur = i->ptr;
239
240 gcc_assert (!cur || cur->prev);
241
242 /* If the iterator is inside a basic block, we need to update the
243 basic block information for all the nodes between FIRST and LAST. */
244 if ((bb = gsi_bb (*i)) != NULL)
245 update_bb_for_stmts (first, last, bb);
246
247 /* Link SEQ after CUR. */
248 if (cur)
249 {
250 last->next = cur->next;
251 if (last->next)
252 {
253 last->next->prev = last;
254 }
255 else
256 gimple_seq_set_last (i->seq, last);
257 first->prev = cur;
258 cur->next = first;
259 }
260 else
261 {
262 gcc_assert (!gimple_seq_last (*i->seq));
263 last->next = NULL;
264 gimple_seq_set_first (i->seq, first);
265 gimple_seq_set_last (i->seq, last);
266 }
267
268 /* Update the iterator, if requested. */
269 switch (m)
270 {
271 case GSI_NEW_STMT:
272 i->ptr = first;
273 break;
274 case GSI_CONTINUE_LINKING:
275 i->ptr = last;
276 break;
277 case GSI_SAME_STMT:
278 gcc_assert (cur);
279 break;
280 default:
281 gcc_unreachable ();
282 }
283}
284
285
286/* Links sequence SEQ after the statement pointed-to by iterator I.
287 MODE is as in gsi_insert_after.
288
289 This function does not scan for new operands. It is provided for
290 the use of the gimplifier, which manipulates statements for which
291 def/use information has not yet been constructed. Most callers
292 should use gsi_insert_seq_after. */
293
294void
295gsi_insert_seq_after_without_update (gimple_stmt_iterator *i, gimple_seq seq,
296 enum gsi_iterator_update mode)
297{
298 gimple_seq_node first, last;
299
300 if (seq == NULL)
301 return;
302
303 /* Don't allow inserting a sequence into itself. */
304 gcc_assert (seq != *i->seq);
305
306 first = gimple_seq_first (seq);
307 last = gimple_seq_last (seq);
308
309 /* Empty sequences need no work. */
310 if (!first || !last)
311 {
312 gcc_assert (first == last);
313 return;
314 }
315
316 gsi_insert_seq_nodes_after (i, first, last, mode);
317}
318
319
320/* Links sequence SEQ after the statement pointed-to by iterator I.
321 MODE is as in gsi_insert_after. Scan the statements in SEQ
322 for new operands. */
323
324void
325gsi_insert_seq_after (gimple_stmt_iterator *i, gimple_seq seq,
326 enum gsi_iterator_update mode)
327{
328 update_modified_stmts (seq);
329 gsi_insert_seq_after_without_update (i, seq, mode);
330}
331
332
333/* Move all statements in the sequence after I to a new sequence.
334 Return this new sequence. */
335
336gimple_seq
337gsi_split_seq_after (gimple_stmt_iterator i)
338{
339 gimple_seq_node cur, next;
340 gimple_seq *pold_seq, new_seq;
341
342 cur = i.ptr;
343
344 /* How can we possibly split after the end, or before the beginning? */
345 gcc_assert (cur && cur->next);
346 next = cur->next;
347
348 pold_seq = i.seq;
349
350 gimple_seq_set_first (&new_seq, next);
351 gimple_seq_set_last (&new_seq, gimple_seq_last (*pold_seq));
352 gimple_seq_set_last (pold_seq, cur);
353 cur->next = NULL;
354
355 return new_seq;
356}
357
358
359/* Set the statement to which GSI points to STMT. This only updates
360 the iterator and the gimple sequence, it doesn't do the bookkeeping
361 of gsi_replace. */
362
363void
364gsi_set_stmt (gimple_stmt_iterator *gsi, gimple *stmt)
365{
366 gimple *orig_stmt = gsi_stmt (*gsi);
367 gimple *prev, *next;
368
369 stmt->next = next = orig_stmt->next;
370 stmt->prev = prev = orig_stmt->prev;
371 /* Note how we don't clear next/prev of orig_stmt. This is so that
372 copies of *GSI our callers might still hold (to orig_stmt)
373 can be advanced as if they too were replaced. */
374 if (prev->next)
375 prev->next = stmt;
376 else
377 gimple_seq_set_first (gsi->seq, stmt);
378 if (next)
379 next->prev = stmt;
380 else
381 gimple_seq_set_last (gsi->seq, stmt);
382
383 gsi->ptr = stmt;
384}
385
386
387/* Move all statements in the sequence before I to a new sequence.
388 Return this new sequence. I is set to the head of the new list. */
389
390void
391gsi_split_seq_before (gimple_stmt_iterator *i, gimple_seq *pnew_seq)
392{
393 gimple_seq_node cur, prev;
394 gimple_seq old_seq;
395
396 cur = i->ptr;
397
398 /* How can we possibly split after the end? */
399 gcc_assert (cur);
400 prev = cur->prev;
401
402 old_seq = *i->seq;
403 if (!prev->next)
404 *i->seq = NULL;
405 i->seq = pnew_seq;
406
407 /* Set the limits on NEW_SEQ. */
408 gimple_seq_set_first (pnew_seq, cur);
409 gimple_seq_set_last (pnew_seq, gimple_seq_last (old_seq));
410
411 /* Cut OLD_SEQ before I. */
412 gimple_seq_set_last (&old_seq, prev);
413 if (prev->next)
414 prev->next = NULL;
415}
416
417
418/* Replace the statement pointed-to by GSI to STMT. If UPDATE_EH_INFO
419 is true, the exception handling information of the original
420 statement is moved to the new statement. Assignments must only be
421 replaced with assignments to the same LHS. Returns whether EH edge
422 cleanup is required. */
423
424bool
425gsi_replace (gimple_stmt_iterator *gsi, gimple *stmt, bool update_eh_info)
426{
427 gimple *orig_stmt = gsi_stmt (*gsi);
428 bool require_eh_edge_purge = false;
429
430 if (stmt == orig_stmt)
431 return false;
432
433 gcc_assert (!gimple_has_lhs (orig_stmt) || !gimple_has_lhs (stmt)
434 || gimple_get_lhs (orig_stmt) == gimple_get_lhs (stmt));
435
436 gimple_set_location (stmt, gimple_location (orig_stmt));
437 gimple_set_bb (stmt, gsi_bb (*gsi));
438
439 /* Preserve EH region information from the original statement, if
440 requested by the caller. */
441 if (update_eh_info)
442 require_eh_edge_purge = maybe_clean_or_replace_eh_stmt (orig_stmt, stmt);
443
444 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
445
446 /* Free all the data flow information for ORIG_STMT. */
447 gimple_set_bb (orig_stmt, NULL);
448 gimple_remove_stmt_histograms (cfun, orig_stmt);
449 delink_stmt_imm_use (orig_stmt);
450
451 gsi_set_stmt (gsi, stmt);
452 gimple_set_modified (stmt, true);
453 update_modified_stmt (stmt);
454 return require_eh_edge_purge;
455}
456
457
458/* Replace the statement pointed-to by GSI with the sequence SEQ.
459 If UPDATE_EH_INFO is true, the exception handling information of
460 the original statement is moved to the last statement of the new
461 sequence. If the old statement is an assignment, then so must
462 be the last statement of the new sequence, and they must have the
463 same LHS. */
464
465void
466gsi_replace_with_seq (gimple_stmt_iterator *gsi, gimple_seq seq,
467 bool update_eh_info)
468{
469 gimple_stmt_iterator seqi;
470 gimple *last;
471 if (gimple_seq_empty_p (seq))
472 {
473 gsi_remove (gsi, true);
474 return;
475 }
476 seqi = gsi_last (seq);
477 last = gsi_stmt (seqi);
478 gsi_remove (&seqi, false);
479 gsi_insert_seq_before (gsi, seq, GSI_SAME_STMT);
480 gsi_replace (gsi, last, update_eh_info);
481}
482
483
484/* Insert statement STMT before the statement pointed-to by iterator I.
485 M specifies how to update iterator I after insertion (see enum
486 gsi_iterator_update).
487
488 This function does not scan for new operands. It is provided for
489 the use of the gimplifier, which manipulates statements for which
490 def/use information has not yet been constructed. Most callers
491 should use gsi_insert_before. */
492
493void
494gsi_insert_before_without_update (gimple_stmt_iterator *i, gimple *stmt,
495 enum gsi_iterator_update m)
496{
497 gsi_insert_seq_nodes_before (i, stmt, stmt, m);
498}
499
500/* Insert statement STMT before the statement pointed-to by iterator I.
501 Update STMT's basic block and scan it for new operands. M
502 specifies how to update iterator I after insertion (see enum
503 gsi_iterator_update). */
504
505void
506gsi_insert_before (gimple_stmt_iterator *i, gimple *stmt,
507 enum gsi_iterator_update m)
508{
509 update_modified_stmt (stmt);
510 gsi_insert_before_without_update (i, stmt, m);
511}
512
513
514/* Insert statement STMT after the statement pointed-to by iterator I.
515 M specifies how to update iterator I after insertion (see enum
516 gsi_iterator_update).
517
518 This function does not scan for new operands. It is provided for
519 the use of the gimplifier, which manipulates statements for which
520 def/use information has not yet been constructed. Most callers
521 should use gsi_insert_after. */
522
523void
524gsi_insert_after_without_update (gimple_stmt_iterator *i, gimple *stmt,
525 enum gsi_iterator_update m)
526{
527 gsi_insert_seq_nodes_after (i, stmt, stmt, m);
528}
529
530
531/* Insert statement STMT after the statement pointed-to by iterator I.
532 Update STMT's basic block and scan it for new operands. M
533 specifies how to update iterator I after insertion (see enum
534 gsi_iterator_update). */
535
536void
537gsi_insert_after (gimple_stmt_iterator *i, gimple *stmt,
538 enum gsi_iterator_update m)
539{
540 update_modified_stmt (stmt);
541 gsi_insert_after_without_update (i, stmt, m);
542}
543
544
545/* Remove the current stmt from the sequence. The iterator is updated
546 to point to the next statement.
547
548 REMOVE_PERMANENTLY is true when the statement is going to be removed
549 from the IL and not reinserted elsewhere. In that case we remove the
550 statement pointed to by iterator I from the EH tables, and free its
551 operand caches. Otherwise we do not modify this information. Returns
552 true whether EH edge cleanup is required. */
553
554bool
555gsi_remove (gimple_stmt_iterator *i, bool remove_permanently)
556{
557 gimple_seq_node cur, next, prev;
558 gimple *stmt = gsi_stmt (*i);
559 bool require_eh_edge_purge = false;
560
561 if (gimple_code (stmt) != GIMPLE_PHI)
562 insert_debug_temps_for_defs (i);
563
564 /* Free all the data flow information for STMT. */
565 gimple_set_bb (stmt, NULL);
566 delink_stmt_imm_use (stmt);
567 gimple_set_modified (stmt, true);
568
569 if (remove_permanently)
570 {
571 if (gimple_debug_nonbind_marker_p (stmt))
572 /* We don't need this to be exact, but try to keep it at least
573 close. */
574 cfun->debug_marker_count--;
575 require_eh_edge_purge = remove_stmt_from_eh_lp (stmt);
576 gimple_remove_stmt_histograms (cfun, stmt);
577 }
578
579 /* Update the iterator and re-wire the links in I->SEQ. */
580 cur = i->ptr;
581 next = cur->next;
582 prev = cur->prev;
583 /* See gsi_set_stmt for why we don't reset prev/next of STMT. */
584
585 if (next)
586 /* Cur is not last. */
587 next->prev = prev;
588 else if (prev->next)
589 /* Cur is last but not first. */
590 gimple_seq_set_last (i->seq, prev);
591
592 if (prev->next)
593 /* Cur is not first. */
594 prev->next = next;
595 else
596 /* Cur is first. */
597 *i->seq = next;
598
599 i->ptr = next;
600
601 return require_eh_edge_purge;
602}
603
604
605/* Finds iterator for STMT. */
606
607gimple_stmt_iterator
608gsi_for_stmt (gimple *stmt)
609{
610 gimple_stmt_iterator i;
611 basic_block bb = gimple_bb (stmt);
612
613 if (gimple_code (stmt) == GIMPLE_PHI)
614 i = gsi_start_phis (bb);
615 else
616 i = gsi_start_bb (bb);
617
618 i.ptr = stmt;
619 return i;
620}
621
622/* Finds iterator for PHI. */
623
624gphi_iterator
625gsi_for_phi (gphi *phi)
626{
627 gphi_iterator i;
628 basic_block bb = gimple_bb (phi);
629
630 i = gsi_start_phis (bb);
631 i.ptr = phi;
632
633 return i;
634}
635
636/* Move the statement at FROM so it comes right after the statement at TO. */
637
638void
639gsi_move_after (gimple_stmt_iterator *from, gimple_stmt_iterator *to)
640{
641 gimple *stmt = gsi_stmt (*from);
642 gsi_remove (from, false);
643
644 /* We must have GSI_NEW_STMT here, as gsi_move_after is sometimes used to
645 move statements to an empty block. */
646 gsi_insert_after (to, stmt, GSI_NEW_STMT);
647}
648
649
650/* Move the statement at FROM so it comes right before the statement
651 at TO. */
652
653void
654gsi_move_before (gimple_stmt_iterator *from, gimple_stmt_iterator *to)
655{
656 gimple *stmt = gsi_stmt (*from);
657 gsi_remove (from, false);
658
659 /* For consistency with gsi_move_after, it might be better to have
660 GSI_NEW_STMT here; however, that breaks several places that expect
661 that TO does not change. */
662 gsi_insert_before (to, stmt, GSI_SAME_STMT);
663}
664
665
666/* Move the statement at FROM to the end of basic block BB. */
667
668void
669gsi_move_to_bb_end (gimple_stmt_iterator *from, basic_block bb)
670{
671 gimple_stmt_iterator last = gsi_last_bb (bb);
672 gcc_checking_assert (gsi_bb (last) == bb);
673
674 /* Have to check gsi_end_p because it could be an empty block. */
675 if (!gsi_end_p (last) && is_ctrl_stmt (gsi_stmt (last)))
676 gsi_move_before (from, &last);
677 else
678 gsi_move_after (from, &last);
679}
680
681
682/* Add STMT to the pending list of edge E. No actual insertion is
683 made until a call to gsi_commit_edge_inserts () is made. */
684
685void
686gsi_insert_on_edge (edge e, gimple *stmt)
687{
688 gimple_seq_add_stmt (&PENDING_STMT (e), stmt);
689}
690
691/* Add the sequence of statements SEQ to the pending list of edge E.
692 No actual insertion is made until a call to gsi_commit_edge_inserts
693 is made. */
694
695void
696gsi_insert_seq_on_edge (edge e, gimple_seq seq)
697{
698 gimple_seq_add_seq (&PENDING_STMT (e), seq);
699}
700
701/* Return a new iterator pointing to the first statement in sequence of
702 statements on edge E. Such statements need to be subsequently moved into a
703 basic block by calling gsi_commit_edge_inserts. */
704
705gimple_stmt_iterator
706gsi_start_edge (edge e)
707{
708 return gsi_start (PENDING_STMT (e));
709}
710
711/* Insert the statement pointed-to by GSI into edge E. Every attempt
712 is made to place the statement in an existing basic block, but
713 sometimes that isn't possible. When it isn't possible, the edge is
714 split and the statement is added to the new block.
715
716 In all cases, the returned *GSI points to the correct location. The
717 return value is true if insertion should be done after the location,
718 or false if it should be done before the location. If a new basic block
719 has to be created, it is stored in *NEW_BB. */
720
721static bool
722gimple_find_edge_insert_loc (edge e, gimple_stmt_iterator *gsi,
723 basic_block *new_bb)
724{
725 basic_block dest, src;
726 gimple *tmp;
727
728 dest = e->dest;
729
730 /* If the destination has one predecessor which has no PHI nodes,
731 insert there. Except for the exit block.
732
733 The requirement for no PHI nodes could be relaxed. Basically we
734 would have to examine the PHIs to prove that none of them used
735 the value set by the statement we want to insert on E. That
736 hardly seems worth the effort. */
737 restart:
738 if (single_pred_p (dest)
739 && gimple_seq_empty_p (phi_nodes (dest))
740 && dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
741 {
742 *gsi = gsi_start_bb (dest);
743 if (gsi_end_p (*gsi))
744 return true;
745
746 /* Make sure we insert after any leading labels. We have to
747 skip debug stmts before or among them, though. We didn't
748 have to skip debug stmts after the last label, but it
749 shouldn't hurt if we do. */
750 tmp = gsi_stmt (*gsi);
751 while (gimple_code (tmp) == GIMPLE_LABEL
752 || is_gimple_debug (tmp))
753 {
754 gsi_next (gsi);
755 if (gsi_end_p (*gsi))
756 break;
757 tmp = gsi_stmt (*gsi);
758 }
759
760 if (gsi_end_p (*gsi))
761 {
762 *gsi = gsi_last_bb (dest);
763 return true;
764 }
765 else
766 return false;
767 }
768
769 /* If the source has one successor, the edge is not abnormal and
770 the last statement does not end a basic block, insert there.
771 Except for the entry block. */
772 src = e->src;
773 if ((e->flags & EDGE_ABNORMAL) == 0
774 && (single_succ_p (src)
775 /* Do not count a fake edge as successor as added to infinite
776 loops by connect_infinite_loops_to_exit. */
777 || (EDGE_COUNT (src->succs) == 2
778 && (EDGE_SUCC (src, 0)->flags & EDGE_FAKE
779 || EDGE_SUCC (src, 1)->flags & EDGE_FAKE)))
780 && src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
781 {
782 *gsi = gsi_last_bb (src);
783 if (gsi_end_p (*gsi))
784 return true;
785
786 tmp = gsi_stmt (*gsi);
787 if (is_gimple_debug (tmp))
788 {
789 gimple_stmt_iterator si = *gsi;
790 gsi_prev_nondebug (&si);
791 if (!gsi_end_p (si))
792 tmp = gsi_stmt (si);
793 /* If we don't have a BB-ending nondebug stmt, we want to
794 insert after the trailing debug stmts. Otherwise, we may
795 insert before the BB-ending nondebug stmt, or split the
796 edge. */
797 if (!stmt_ends_bb_p (tmp))
798 return true;
799 *gsi = si;
800 }
801 else if (!stmt_ends_bb_p (tmp))
802 return true;
803
804 switch (gimple_code (tmp))
805 {
806 case GIMPLE_RETURN:
807 case GIMPLE_RESX:
808 return false;
809 default:
810 break;
811 }
812 }
813
814 /* Otherwise, create a new basic block, and split this edge. */
815 dest = split_edge (e);
816 if (new_bb)
817 *new_bb = dest;
818 e = single_pred_edge (dest);
819 goto restart;
820}
821
822
823/* Similar to gsi_insert_on_edge+gsi_commit_edge_inserts. If a new
824 block has to be created, it is returned. */
825
826basic_block
827gsi_insert_on_edge_immediate (edge e, gimple *stmt)
828{
829 gimple_stmt_iterator gsi;
830 basic_block new_bb = NULL;
831 bool ins_after;
832
833 gcc_assert (!PENDING_STMT (e));
834
835 ins_after = gimple_find_edge_insert_loc (e, &gsi, &new_bb);
836
837 update_call_edge_frequencies (stmt, gsi.bb);
838
839 if (ins_after)
840 gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
841 else
842 gsi_insert_before (&gsi, stmt, GSI_NEW_STMT);
843
844 return new_bb;
845}
846
847/* Insert STMTS on edge E. If a new block has to be created, it
848 is returned. */
849
850basic_block
851gsi_insert_seq_on_edge_immediate (edge e, gimple_seq stmts)
852{
853 gimple_stmt_iterator gsi;
854 basic_block new_bb = NULL;
855 bool ins_after;
856
857 gcc_assert (!PENDING_STMT (e));
858
859 ins_after = gimple_find_edge_insert_loc (e, &gsi, &new_bb);
860 update_call_edge_frequencies (gimple_seq_first (stmts), gsi.bb);
861
862 if (ins_after)
863 gsi_insert_seq_after (&gsi, stmts, GSI_NEW_STMT);
864 else
865 gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT);
866
867 return new_bb;
868}
869
870/* This routine will commit all pending edge insertions, creating any new
871 basic blocks which are necessary. */
872
873void
874gsi_commit_edge_inserts (void)
875{
876 basic_block bb;
877 edge e;
878 edge_iterator ei;
879
880 gsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)),
881 NULL);
882
883 FOR_EACH_BB_FN (bb, cfun)
884 FOR_EACH_EDGE (e, ei, bb->succs)
885 gsi_commit_one_edge_insert (e, NULL);
886}
887
888
889/* Commit insertions pending at edge E. If a new block is created, set NEW_BB
890 to this block, otherwise set it to NULL. */
891
892void
893gsi_commit_one_edge_insert (edge e, basic_block *new_bb)
894{
895 if (new_bb)
896 *new_bb = NULL;
897
898 if (PENDING_STMT (e))
899 {
900 gimple_stmt_iterator gsi;
901 gimple_seq seq = PENDING_STMT (e);
902 bool ins_after;
903
904 PENDING_STMT (e) = NULL;
905
906 ins_after = gimple_find_edge_insert_loc (e, &gsi, new_bb);
907 update_call_edge_frequencies (gimple_seq_first (seq), gsi.bb);
908
909 if (ins_after)
910 gsi_insert_seq_after (&gsi, seq, GSI_NEW_STMT);
911 else
912 gsi_insert_seq_before (&gsi, seq, GSI_NEW_STMT);
913 }
914}
915
916/* Returns iterator at the start of the list of phi nodes of BB. */
917
918gphi_iterator
919gsi_start_phis (basic_block bb)
920{
921 gimple_seq *pseq = phi_nodes_ptr (bb);
922
923 /* Adapted from gsi_start_1. */
924 gphi_iterator i;
925
926 i.ptr = gimple_seq_first (*pseq);
927 i.seq = pseq;
928 i.bb = i.ptr ? gimple_bb (i.ptr) : NULL;
929
930 return i;
931}
932