summaryrefslogtreecommitdiff
path: root/gcc/cfglayout.c
blob: f7d4d10440355a17c69837e80cfde989fd005653 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
/* Basic block reordering routines for the GNU compiler.
   Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "obstack.h"
#include "basic-block.h"
#include "insn-config.h"
#include "output.h"
#include "function.h"
#include "cfglayout.h"
#include "cfgloop.h"
#include "target.h"
#include "ggc.h"
#include "alloc-pool.h"
#include "flags.h"
#include "tree-pass.h"
#include "df.h"
#include "vecprim.h"
#include "emit-rtl.h"

/* Holds the interesting trailing notes for the function.  */
rtx cfg_layout_function_footer;
rtx cfg_layout_function_header;

static rtx skip_insns_after_block (basic_block);
static void record_effective_endpoints (void);
static rtx label_for_bb (basic_block);
static void fixup_reorder_chain (void);

static void change_scope (rtx, tree, tree);

void verify_insn_chain (void);
static void fixup_fallthru_exit_predecessor (void);
static tree insn_scope (const_rtx);

rtx
unlink_insn_chain (rtx first, rtx last)
{
  rtx prevfirst = PREV_INSN (first);
  rtx nextlast = NEXT_INSN (last);

  PREV_INSN (first) = NULL;
  NEXT_INSN (last) = NULL;
  if (prevfirst)
    NEXT_INSN (prevfirst) = nextlast;
  if (nextlast)
    PREV_INSN (nextlast) = prevfirst;
  else
    set_last_insn (prevfirst);
  if (!prevfirst)
    set_first_insn (nextlast);
  return first;
}

/* Skip over inter-block insns occurring after BB which are typically
   associated with BB (e.g., barriers). If there are any such insns,
   we return the last one. Otherwise, we return the end of BB.  */

static rtx
skip_insns_after_block (basic_block bb)
{
  rtx insn, last_insn, next_head, prev;

  next_head = NULL_RTX;
  if (bb->next_bb != EXIT_BLOCK_PTR)
    next_head = BB_HEAD (bb->next_bb);

  for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; )
    {
      if (insn == next_head)
	break;

      switch (GET_CODE (insn))
	{
	case BARRIER:
	  last_insn = insn;
	  continue;

	case NOTE:
	  switch (NOTE_KIND (insn))
	    {
	    case NOTE_INSN_BLOCK_END:
	      gcc_unreachable ();
	      continue;
	    default:
	      continue;
	      break;
	    }
	  break;

	case CODE_LABEL:
	  if (NEXT_INSN (insn)
	      && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
	    {
	      insn = NEXT_INSN (insn);
	      last_insn = insn;
	      continue;
	    }
	  break;

	default:
	  break;
	}

      break;
    }

  /* It is possible to hit contradictory sequence.  For instance:

     jump_insn
     NOTE_INSN_BLOCK_BEG
     barrier

     Where barrier belongs to jump_insn, but the note does not.  This can be
     created by removing the basic block originally following
     NOTE_INSN_BLOCK_BEG.  In such case reorder the notes.  */

  for (insn = last_insn; insn != BB_END (bb); insn = prev)
    {
      prev = PREV_INSN (insn);
      if (NOTE_P (insn))
	switch (NOTE_KIND (insn))
	  {
	  case NOTE_INSN_BLOCK_END:
	    gcc_unreachable ();
	    break;
	  case NOTE_INSN_DELETED:
	  case NOTE_INSN_DELETED_LABEL:
	    continue;
	  default:
	    reorder_insns (insn, insn, last_insn);
	  }
    }

  return last_insn;
}

/* Locate or create a label for a given basic block.  */

static rtx
label_for_bb (basic_block bb)
{
  rtx label = BB_HEAD (bb);

  if (!LABEL_P (label))
    {
      if (dump_file)
	fprintf (dump_file, "Emitting label for block %d\n", bb->index);

      label = block_label (bb);
    }

  return label;
}

/* Locate the effective beginning and end of the insn chain for each
   block, as defined by skip_insns_after_block above.  */

static void
record_effective_endpoints (void)
{
  rtx next_insn;
  basic_block bb;
  rtx insn;

  for (insn = get_insns ();
       insn
       && NOTE_P (insn)
       && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK;
       insn = NEXT_INSN (insn))
    continue;
  /* No basic blocks at all?  */
  gcc_assert (insn);

  if (PREV_INSN (insn))
    cfg_layout_function_header =
	    unlink_insn_chain (get_insns (), PREV_INSN (insn));
  else
    cfg_layout_function_header = NULL_RTX;

  next_insn = get_insns ();
  FOR_EACH_BB (bb)
    {
      rtx end;

      if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb))
	bb->il.rtl->header = unlink_insn_chain (next_insn,
					      PREV_INSN (BB_HEAD (bb)));
      end = skip_insns_after_block (bb);
      if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end)
	bb->il.rtl->footer = unlink_insn_chain (NEXT_INSN (BB_END (bb)), end);
      next_insn = NEXT_INSN (BB_END (bb));
    }

  cfg_layout_function_footer = next_insn;
  if (cfg_layout_function_footer)
    cfg_layout_function_footer = unlink_insn_chain (cfg_layout_function_footer, get_last_insn ());
}

/* Data structures representing mapping of INSN_LOCATOR into scope blocks, line
   numbers and files.  In order to be GGC friendly we need to use separate
   varrays.  This also slightly improve the memory locality in binary search.
   The _locs array contains locators where the given property change.  The
   block_locators_blocks contains the scope block that is used for all insn
   locator greater than corresponding block_locators_locs value and smaller
   than the following one.  Similarly for the other properties.  */
static VEC(int,heap) *block_locators_locs;
static GTY(()) VEC(tree,gc) *block_locators_blocks;
static VEC(int,heap) *locations_locators_locs;
DEF_VEC_O(location_t);
DEF_VEC_ALLOC_O(location_t,heap);
static VEC(location_t,heap) *locations_locators_vals;
int prologue_locator;
int epilogue_locator;

/* Hold current location information and last location information, so the
   datastructures are built lazily only when some instructions in given
   place are needed.  */
static location_t curr_location, last_location;
static tree curr_block, last_block;
static int curr_rtl_loc = -1;

/* Allocate insn locator datastructure.  */
void
insn_locators_alloc (void)
{
  prologue_locator = epilogue_locator = 0;

  block_locators_locs = VEC_alloc (int, heap, 32);
  block_locators_blocks = VEC_alloc (tree, gc, 32);
  locations_locators_locs = VEC_alloc (int, heap, 32);
  locations_locators_vals = VEC_alloc (location_t, heap, 32);

  last_location = -1;
  curr_location = -1;
  curr_block = NULL;
  last_block = NULL;
  curr_rtl_loc = 0;
}

/* At the end of emit stage, clear current location.  */
void
insn_locators_finalize (void)
{
  if (curr_rtl_loc >= 0)
    epilogue_locator = curr_insn_locator ();
  curr_rtl_loc = -1;
}

/* Allocate insn locator datastructure.  */
void
insn_locators_free (void)
{
  prologue_locator = epilogue_locator = 0;

  VEC_free (int, heap, block_locators_locs);
  VEC_free (tree,gc, block_locators_blocks);
  VEC_free (int, heap, locations_locators_locs);
  VEC_free (location_t, heap, locations_locators_vals);
}


/* Set current location.  */
void
set_curr_insn_source_location (location_t location)
{
  /* IV opts calls into RTL expansion to compute costs of operations.  At this
     time locators are not initialized.  */
  if (curr_rtl_loc == -1)
    return;
  curr_location = location;
}

/* Get current location.  */
location_t
get_curr_insn_source_location (void)
{
  return curr_location;
}

/* Set current scope block.  */
void
set_curr_insn_block (tree b)
{
  /* IV opts calls into RTL expansion to compute costs of operations.  At this
     time locators are not initialized.  */
  if (curr_rtl_loc == -1)
    return;
  if (b)
    curr_block = b;
}

/* Get current scope block.  */
tree
get_curr_insn_block (void)
{
  return curr_block;
}

/* Return current insn locator.  */
int
curr_insn_locator (void)
{
  if (curr_rtl_loc == -1)
    return 0;
  if (last_block != curr_block)
    {
      curr_rtl_loc++;
      VEC_safe_push (int, heap, block_locators_locs, curr_rtl_loc);
      VEC_safe_push (tree, gc, block_locators_blocks, curr_block);
      last_block = curr_block;
    }
  if (last_location != curr_location)
    {
      curr_rtl_loc++;
      VEC_safe_push (int, heap, locations_locators_locs, curr_rtl_loc);
      VEC_safe_push (location_t, heap, locations_locators_vals, &curr_location);
      last_location = curr_location;
    }
  return curr_rtl_loc;
}

static unsigned int
into_cfg_layout_mode (void)
{
  cfg_layout_initialize (0);
  return 0;
}

static unsigned int
outof_cfg_layout_mode (void)
{
  basic_block bb;

  FOR_EACH_BB (bb)
    if (bb->next_bb != EXIT_BLOCK_PTR)
      bb->aux = bb->next_bb;

  cfg_layout_finalize ();

  return 0;
}

struct rtl_opt_pass pass_into_cfg_layout_mode =
{
 {
  RTL_PASS,
  "into_cfglayout",                     /* name */
  NULL,                                 /* gate */
  into_cfg_layout_mode,                 /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_CFG,                               /* tv_id */
  0,                                    /* properties_required */
  PROP_cfglayout,                       /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  TODO_dump_func,                       /* todo_flags_finish */
 }
};

struct rtl_opt_pass pass_outof_cfg_layout_mode =
{
 {
  RTL_PASS,
  "outof_cfglayout",                    /* name */
  NULL,                                 /* gate */
  outof_cfg_layout_mode,                /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_CFG,                               /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  PROP_cfglayout,                       /* properties_destroyed */
  0,                                    /* todo_flags_start */
  TODO_dump_func,                       /* todo_flags_finish */
 }
};

/* Return scope resulting from combination of S1 and S2.  */
static tree
choose_inner_scope (tree s1, tree s2)
{
   if (!s1)
     return s2;
   if (!s2)
     return s1;
   if (BLOCK_NUMBER (s1) > BLOCK_NUMBER (s2))
     return s1;
   return s2;
}

/* Emit lexical block notes needed to change scope from S1 to S2.  */

static void
change_scope (rtx orig_insn, tree s1, tree s2)
{
  rtx insn = orig_insn;
  tree com = NULL_TREE;
  tree ts1 = s1, ts2 = s2;
  tree s;

  while (ts1 != ts2)
    {
      gcc_assert (ts1 && ts2);
      if (BLOCK_NUMBER (ts1) > BLOCK_NUMBER (ts2))
	ts1 = BLOCK_SUPERCONTEXT (ts1);
      else if (BLOCK_NUMBER (ts1) < BLOCK_NUMBER (ts2))
	ts2 = BLOCK_SUPERCONTEXT (ts2);
      else
	{
	  ts1 = BLOCK_SUPERCONTEXT (ts1);
	  ts2 = BLOCK_SUPERCONTEXT (ts2);
	}
    }
  com = ts1;

  /* Close scopes.  */
  s = s1;
  while (s != com)
    {
      rtx note = emit_note_before (NOTE_INSN_BLOCK_END, insn);
      NOTE_BLOCK (note) = s;
      s = BLOCK_SUPERCONTEXT (s);
    }

  /* Open scopes.  */
  s = s2;
  while (s != com)
    {
      insn = emit_note_before (NOTE_INSN_BLOCK_BEG, insn);
      NOTE_BLOCK (insn) = s;
      s = BLOCK_SUPERCONTEXT (s);
    }
}

/* Return lexical scope block locator belongs to.  */
static tree
locator_scope (int loc)
{
  int max = VEC_length (int, block_locators_locs);
  int min = 0;

  /* When block_locators_locs was initialized, the pro- and epilogue
     insns didn't exist yet and can therefore not be found this way.
     But we know that they belong to the outer most block of the
     current function.
     Without this test, the prologue would be put inside the block of
     the first valid instruction in the function and when that first
     insn is part of an inlined function then the low_pc of that
     inlined function is messed up.  Likewise for the epilogue and
     the last valid instruction.  */
  if (loc == prologue_locator || loc == epilogue_locator)
    return DECL_INITIAL (cfun->decl);

  if (!max || !loc)
    return NULL;
  while (1)
    {
      int pos = (min + max) / 2;
      int tmp = VEC_index (int, block_locators_locs, pos);

      if (tmp <= loc && min != pos)
	min = pos;
      else if (tmp > loc && max != pos)
	max = pos;
      else
	{
	  min = pos;
	  break;
	}
    }
  return VEC_index (tree, block_locators_blocks, min);
}

/* Return lexical scope block insn belongs to.  */
static tree
insn_scope (const_rtx insn)
{
  return locator_scope (INSN_LOCATOR (insn));
}

/* Return line number of the statement specified by the locator.  */
location_t
locator_location (int loc)
{
  int max = VEC_length (int, locations_locators_locs);
  int min = 0;

  while (1)
    {
      int pos = (min + max) / 2;
      int tmp = VEC_index (int, locations_locators_locs, pos);

      if (tmp <= loc && min != pos)
	min = pos;
      else if (tmp > loc && max != pos)
	max = pos;
      else
	{
	  min = pos;
	  break;
	}
    }
  return *VEC_index (location_t, locations_locators_vals, min);
}

/* Return source line of the statement that produced this insn.  */
int
locator_line (int loc)
{
  expanded_location xloc;
  if (!loc)
    return 0;
  else
    xloc = expand_location (locator_location (loc));
  return xloc.line;
}

/* Return line number of the statement that produced this insn.  */
int
insn_line (const_rtx insn)
{
  return locator_line (INSN_LOCATOR (insn));
}

/* Return source file of the statement specified by LOC.  */
const char *
locator_file (int loc)
{
  expanded_location xloc;
  if (!loc)
    return 0;
  else
    xloc = expand_location (locator_location (loc));
  return xloc.file;
}

/* Return source file of the statement that produced this insn.  */
const char *
insn_file (const_rtx insn)
{
  return locator_file (INSN_LOCATOR (insn));
}

/* Return true if LOC1 and LOC2 locators have the same location and scope.  */
bool
locator_eq (int loc1, int loc2)
{
  if (loc1 == loc2)
    return true;
  if (locator_location (loc1) != locator_location (loc2))
    return false;
  return locator_scope (loc1) == locator_scope (loc2);
}

/* Rebuild all the NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes based
   on the scope tree and the newly reordered instructions.  */

void
reemit_insn_block_notes (void)
{
  tree cur_block = DECL_INITIAL (cfun->decl);
  rtx insn, note;

  insn = get_insns ();
  if (!active_insn_p (insn))
    insn = next_active_insn (insn);
  for (; insn; insn = next_active_insn (insn))
    {
      tree this_block;

      /* Avoid putting scope notes between jump table and its label.  */
      if (JUMP_TABLE_DATA_P (insn))
	continue;

      this_block = insn_scope (insn);
      /* For sequences compute scope resulting from merging all scopes
	 of instructions nested inside.  */
      if (GET_CODE (PATTERN (insn)) == SEQUENCE)
	{
	  int i;
	  rtx body = PATTERN (insn);

	  this_block = NULL;
	  for (i = 0; i < XVECLEN (body, 0); i++)
	    this_block = choose_inner_scope (this_block,
					 insn_scope (XVECEXP (body, 0, i)));
	}
      if (! this_block)
	continue;

      if (this_block != cur_block)
	{
	  change_scope (insn, cur_block, this_block);
	  cur_block = this_block;
	}
    }

  /* change_scope emits before the insn, not after.  */
  note = emit_note (NOTE_INSN_DELETED);
  change_scope (note, cur_block, DECL_INITIAL (cfun->decl));
  delete_insn (note);

  reorder_blocks ();
}


/* Link the basic blocks in the correct order, compacting the basic
   block queue while at it.  This also clears the visited flag on
   all basic blocks.  If STAY_IN_CFGLAYOUT_MODE is false, this function
   also clears the basic block header and footer fields.

   This function is usually called after a pass (e.g. tracer) finishes
   some transformations while in cfglayout mode.  The required sequence
   of the basic blocks is in a linked list along the bb->aux field.
   This functions re-links the basic block prev_bb and next_bb pointers
   accordingly, and it compacts and renumbers the blocks.  */

void
relink_block_chain (bool stay_in_cfglayout_mode)
{
  basic_block bb, prev_bb;
  int index;

  /* Maybe dump the re-ordered sequence.  */
  if (dump_file)
    {
      fprintf (dump_file, "Reordered sequence:\n");
      for (bb = ENTRY_BLOCK_PTR->next_bb, index = NUM_FIXED_BLOCKS;
	   bb;
	   bb = (basic_block) bb->aux, index++)
	{
	  fprintf (dump_file, " %i ", index);
	  if (get_bb_original (bb))
	    fprintf (dump_file, "duplicate of %i ",
		     get_bb_original (bb)->index);
	  else if (forwarder_block_p (bb)
		   && !LABEL_P (BB_HEAD (bb)))
	    fprintf (dump_file, "compensation ");
	  else
	    fprintf (dump_file, "bb %i ", bb->index);
	  fprintf (dump_file, " [%i]\n", bb->frequency);
	}
    }

  /* Now reorder the blocks.  */
  prev_bb = ENTRY_BLOCK_PTR;
  bb = ENTRY_BLOCK_PTR->next_bb;
  for (; bb; prev_bb = bb, bb = (basic_block) bb->aux)
    {
      bb->prev_bb = prev_bb;
      prev_bb->next_bb = bb;
    }
  prev_bb->next_bb = EXIT_BLOCK_PTR;
  EXIT_BLOCK_PTR->prev_bb = prev_bb;

  /* Then, clean up the aux and visited fields.  */
  FOR_ALL_BB (bb)
    {
      bb->aux = NULL;
      bb->il.rtl->visited = 0;
      if (!stay_in_cfglayout_mode)
	bb->il.rtl->header = bb->il.rtl->footer = NULL;
    }

  /* Maybe reset the original copy tables, they are not valid anymore
     when we renumber the basic blocks in compact_blocks.  If we are
     are going out of cfglayout mode, don't re-allocate the tables.  */
  free_original_copy_tables ();
  if (stay_in_cfglayout_mode)
    initialize_original_copy_tables ();

  /* Finally, put basic_block_info in the new order.  */
  compact_blocks ();
}


/* Given a reorder chain, rearrange the code to match.  */

static void
fixup_reorder_chain (void)
{
  basic_block bb;
  rtx insn = NULL;

  if (cfg_layout_function_header)
    {
      set_first_insn (cfg_layout_function_header);
      insn = cfg_layout_function_header;
      while (NEXT_INSN (insn))
	insn = NEXT_INSN (insn);
    }

  /* First do the bulk reordering -- rechain the blocks without regard to
     the needed changes to jumps and labels.  */

  for (bb = ENTRY_BLOCK_PTR->next_bb; bb; bb = (basic_block) bb->aux)
    {
      if (bb->il.rtl->header)
	{
	  if (insn)
	    NEXT_INSN (insn) = bb->il.rtl->header;
	  else
	    set_first_insn (bb->il.rtl->header);
	  PREV_INSN (bb->il.rtl->header) = insn;
	  insn = bb->il.rtl->header;
	  while (NEXT_INSN (insn))
	    insn = NEXT_INSN (insn);
	}
      if (insn)
	NEXT_INSN (insn) = BB_HEAD (bb);
      else
	set_first_insn (BB_HEAD (bb));
      PREV_INSN (BB_HEAD (bb)) = insn;
      insn = BB_END (bb);
      if (bb->il.rtl->footer)
	{
	  NEXT_INSN (insn) = bb->il.rtl->footer;
	  PREV_INSN (bb->il.rtl->footer) = insn;
	  while (NEXT_INSN (insn))
	    insn = NEXT_INSN (insn);
	}
    }

  NEXT_INSN (insn) = cfg_layout_function_footer;
  if (cfg_layout_function_footer)
    PREV_INSN (cfg_layout_function_footer) = insn;

  while (NEXT_INSN (insn))
    insn = NEXT_INSN (insn);

  set_last_insn (insn);
#ifdef ENABLE_CHECKING
  verify_insn_chain ();
#endif

  /* Now add jumps and labels as needed to match the blocks new
     outgoing edges.  */

  for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = (basic_block) bb->aux)
    {
      edge e_fall, e_taken, e;
      rtx bb_end_insn;
      basic_block nb;
      edge_iterator ei;

      if (EDGE_COUNT (bb->succs) == 0)
	continue;

      /* Find the old fallthru edge, and another non-EH edge for
	 a taken jump.  */
      e_taken = e_fall = NULL;

      FOR_EACH_EDGE (e, ei, bb->succs)
	if (e->flags & EDGE_FALLTHRU)
	  e_fall = e;
	else if (! (e->flags & EDGE_EH))
	  e_taken = e;

      bb_end_insn = BB_END (bb);
      if (JUMP_P (bb_end_insn))
	{
	  if (any_condjump_p (bb_end_insn))
	    {
	      /* This might happen if the conditional jump has side
		 effects and could therefore not be optimized away.
		 Make the basic block to end with a barrier in order
		 to prevent rtl_verify_flow_info from complaining.  */
	      if (!e_fall)
		{
		  gcc_assert (!onlyjump_p (bb_end_insn)
			      || returnjump_p (bb_end_insn));
		  bb->il.rtl->footer = emit_barrier_after (bb_end_insn);
		  continue;
		}

	      /* If the old fallthru is still next, nothing to do.  */
	      if (bb->aux == e_fall->dest
		  || e_fall->dest == EXIT_BLOCK_PTR)
		continue;

	      /* The degenerated case of conditional jump jumping to the next
		 instruction can happen for jumps with side effects.  We need
		 to construct a forwarder block and this will be done just
		 fine by force_nonfallthru below.  */
	      if (!e_taken)
		;

	      /* There is another special case: if *neither* block is next,
		 such as happens at the very end of a function, then we'll
		 need to add a new unconditional jump.  Choose the taken
		 edge based on known or assumed probability.  */
	      else if (bb->aux != e_taken->dest)
		{
		  rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0);

		  if (note
		      && INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2
		      && invert_jump (bb_end_insn,
				      (e_fall->dest == EXIT_BLOCK_PTR
				       ? NULL_RTX
				       : label_for_bb (e_fall->dest)), 0))
		    {
		      e_fall->flags &= ~EDGE_FALLTHRU;
		      gcc_checking_assert (could_fall_through
					   (e_taken->src, e_taken->dest));
		      e_taken->flags |= EDGE_FALLTHRU;
		      update_br_prob_note (bb);
		      e = e_fall, e_fall = e_taken, e_taken = e;
		    }
		}

	      /* If the "jumping" edge is a crossing edge, and the fall
		 through edge is non-crossing, leave things as they are.  */
	      else if ((e_taken->flags & EDGE_CROSSING)
		       && !(e_fall->flags & EDGE_CROSSING))
		continue;

	      /* Otherwise we can try to invert the jump.  This will
		 basically never fail, however, keep up the pretense.  */
	      else if (invert_jump (bb_end_insn,
				    (e_fall->dest == EXIT_BLOCK_PTR
				     ? NULL_RTX
				     : label_for_bb (e_fall->dest)), 0))
		{
		  e_fall->flags &= ~EDGE_FALLTHRU;
		  gcc_checking_assert (could_fall_through
				       (e_taken->src, e_taken->dest));
		  e_taken->flags |= EDGE_FALLTHRU;
		  update_br_prob_note (bb);
		  continue;
		}
	    }
	  else if (extract_asm_operands (PATTERN (bb_end_insn)) != NULL)
	    {
	      /* If the old fallthru is still next or if
		 asm goto doesn't have a fallthru (e.g. when followed by
		 __builtin_unreachable ()), nothing to do.  */
	      if (! e_fall
		  || bb->aux == e_fall->dest
		  || e_fall->dest == EXIT_BLOCK_PTR)
		continue;

	      /* Otherwise we'll have to use the fallthru fixup below.  */
	    }
	  else
	    {
	      /* Otherwise we have some return, switch or computed
		 jump.  In the 99% case, there should not have been a
		 fallthru edge.  */
	      gcc_assert (returnjump_p (bb_end_insn) || !e_fall);
	      continue;
	    }
	}
      else
	{
	  /* No fallthru implies a noreturn function with EH edges, or
	     something similarly bizarre.  In any case, we don't need to
	     do anything.  */
	  if (! e_fall)
	    continue;

	  /* If the fallthru block is still next, nothing to do.  */
	  if (bb->aux == e_fall->dest)
	    continue;

	  /* A fallthru to exit block.  */
	  if (e_fall->dest == EXIT_BLOCK_PTR)
	    continue;
	}

      /* We got here if we need to add a new jump insn.  */
      nb = force_nonfallthru (e_fall);
      if (nb)
	{
	  nb->il.rtl->visited = 1;
	  nb->aux = bb->aux;
	  bb->aux = nb;
	  /* Don't process this new block.  */
	  bb = nb;

	  /* Make sure new bb is tagged for correct section (same as
	     fall-thru source, since you cannot fall-throu across
	     section boundaries).  */
	  BB_COPY_PARTITION (e_fall->src, single_pred (bb));
	  if (flag_reorder_blocks_and_partition
	      && targetm.have_named_sections
	      && JUMP_P (BB_END (bb))
	      && !any_condjump_p (BB_END (bb))
	      && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING))
	    add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
	}
    }

  relink_block_chain (/*stay_in_cfglayout_mode=*/false);

  /* Annoying special case - jump around dead jumptables left in the code.  */
  FOR_EACH_BB (bb)
    {
      edge e = find_fallthru_edge (bb->succs);

      if (e && !can_fallthru (e->src, e->dest))
	force_nonfallthru (e);
    }

  /* Ensure goto_locus from edges has some instructions with that locus
     in RTL.  */
  if (!optimize)
    FOR_EACH_BB (bb)
      {
        edge e;
        edge_iterator ei;

        FOR_EACH_EDGE (e, ei, bb->succs)
	  if (e->goto_locus && !(e->flags & EDGE_ABNORMAL))
	    {
	      edge e2;
	      edge_iterator ei2;
	      basic_block dest, nb;
	      rtx end;

	      insn = BB_END (e->src);
	      end = PREV_INSN (BB_HEAD (e->src));
	      while (insn != end
		     && (!NONDEBUG_INSN_P (insn) || INSN_LOCATOR (insn) == 0))
		insn = PREV_INSN (insn);
	      if (insn != end
		  && locator_eq (INSN_LOCATOR (insn), (int) e->goto_locus))
		continue;
	      if (simplejump_p (BB_END (e->src))
		  && INSN_LOCATOR (BB_END (e->src)) == 0)
		{
		  INSN_LOCATOR (BB_END (e->src)) = e->goto_locus;
		  continue;
		}
	      dest = e->dest;
	      if (dest == EXIT_BLOCK_PTR)
		{
		  /* Non-fallthru edges to the exit block cannot be split.  */
		  if (!(e->flags & EDGE_FALLTHRU))
		    continue;
		}
	      else
		{
		  insn = BB_HEAD (dest);
		  end = NEXT_INSN (BB_END (dest));
		  while (insn != end && !NONDEBUG_INSN_P (insn))
		    insn = NEXT_INSN (insn);
		  if (insn != end && INSN_LOCATOR (insn)
		      && locator_eq (INSN_LOCATOR (insn), (int) e->goto_locus))
		    continue;
		}
	      nb = split_edge (e);
	      if (!INSN_P (BB_END (nb)))
		BB_END (nb) = emit_insn_after_noloc (gen_nop (), BB_END (nb),
						     nb);
	      INSN_LOCATOR (BB_END (nb)) = e->goto_locus;

	      /* If there are other incoming edges to the destination block
		 with the same goto locus, redirect them to the new block as
		 well, this can prevent other such blocks from being created
		 in subsequent iterations of the loop.  */
	      for (ei2 = ei_start (dest->preds); (e2 = ei_safe_edge (ei2)); )
		if (e2->goto_locus
		    && !(e2->flags & (EDGE_ABNORMAL | EDGE_FALLTHRU))
		    && locator_eq (e->goto_locus, e2->goto_locus))
		  redirect_edge_and_branch (e2, nb);
		else
		  ei_next (&ei2);
	    }
      }
}

/* Perform sanity checks on the insn chain.
   1. Check that next/prev pointers are consistent in both the forward and
      reverse direction.
   2. Count insns in chain, going both directions, and check if equal.
   3. Check that get_last_insn () returns the actual end of chain.  */

DEBUG_FUNCTION void
verify_insn_chain (void)
{
  rtx x, prevx, nextx;
  int insn_cnt1, insn_cnt2;

  for (prevx = NULL, insn_cnt1 = 1, x = get_insns ();
       x != 0;
       prevx = x, insn_cnt1++, x = NEXT_INSN (x))
    gcc_assert (PREV_INSN (x) == prevx);

  gcc_assert (prevx == get_last_insn ());

  for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn ();
       x != 0;
       nextx = x, insn_cnt2++, x = PREV_INSN (x))
    gcc_assert (NEXT_INSN (x) == nextx);

  gcc_assert (insn_cnt1 == insn_cnt2);
}

/* If we have assembler epilogues, the block falling through to exit must
   be the last one in the reordered chain when we reach final.  Ensure
   that this condition is met.  */
static void
fixup_fallthru_exit_predecessor (void)
{
  edge e;
  basic_block bb = NULL;

  /* This transformation is not valid before reload, because we might
     separate a call from the instruction that copies the return
     value.  */
  gcc_assert (reload_completed);

  e = find_fallthru_edge (EXIT_BLOCK_PTR->preds);
  if (e)
    bb = e->src;

  if (bb && bb->aux)
    {
      basic_block c = ENTRY_BLOCK_PTR->next_bb;

      /* If the very first block is the one with the fall-through exit
	 edge, we have to split that block.  */
      if (c == bb)
	{
	  bb = split_block (bb, NULL)->dest;
	  bb->aux = c->aux;
	  c->aux = bb;
	  bb->il.rtl->footer = c->il.rtl->footer;
	  c->il.rtl->footer = NULL;
	}

      while (c->aux != bb)
	c = (basic_block) c->aux;

      c->aux = bb->aux;
      while (c->aux)
	c = (basic_block) c->aux;

      c->aux = bb;
      bb->aux = NULL;
    }
}

/* In case there are more than one fallthru predecessors of exit, force that
   there is only one.  */

static void
force_one_exit_fallthru (void)
{
  edge e, predecessor = NULL;
  bool more = false;
  edge_iterator ei;
  basic_block forwarder, bb;

  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
    if (e->flags & EDGE_FALLTHRU)
      {
	if (predecessor == NULL)
	  predecessor = e;
	else
	  {
	    more = true;
	    break;
	  }
      }

  if (!more)
    return;

  /* Exit has several fallthru predecessors.  Create a forwarder block for
     them.  */
  forwarder = split_edge (predecessor);
  for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
    {
      if (e->src == forwarder
	  || !(e->flags & EDGE_FALLTHRU))
	ei_next (&ei);
      else
	redirect_edge_and_branch_force (e, forwarder);
    }

  /* Fix up the chain of blocks -- make FORWARDER immediately precede the
     exit block.  */
  FOR_EACH_BB (bb)
    {
      if (bb->aux == NULL && bb != forwarder)
	{
	  bb->aux = forwarder;
	  break;
	}
    }
}

/* Return true in case it is possible to duplicate the basic block BB.  */

/* We do not want to declare the function in a header file, since it should
   only be used through the cfghooks interface, and we do not want to move
   it to cfgrtl.c since it would require also moving quite a lot of related
   code.  */
extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);

bool
cfg_layout_can_duplicate_bb_p (const_basic_block bb)
{
  /* Do not attempt to duplicate tablejumps, as we need to unshare
     the dispatch table.  This is difficult to do, as the instructions
     computing jump destination may be hoisted outside the basic block.  */
  if (tablejump_p (BB_END (bb), NULL, NULL))
    return false;

  /* Do not duplicate blocks containing insns that can't be copied.  */
  if (targetm.cannot_copy_insn_p)
    {
      rtx insn = BB_HEAD (bb);
      while (1)
	{
	  if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn))
	    return false;
	  if (insn == BB_END (bb))
	    break;
	  insn = NEXT_INSN (insn);
	}
    }

  return true;
}

rtx
duplicate_insn_chain (rtx from, rtx to)
{
  rtx insn, last, copy;

  /* Avoid updating of boundaries of previous basic block.  The
     note will get removed from insn stream in fixup.  */
  last = emit_note (NOTE_INSN_DELETED);

  /* Create copy at the end of INSN chain.  The chain will
     be reordered later.  */
  for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn))
    {
      switch (GET_CODE (insn))
	{
	case DEBUG_INSN:
	case INSN:
	case CALL_INSN:
	case JUMP_INSN:
	  /* Avoid copying of dispatch tables.  We never duplicate
	     tablejumps, so this can hit only in case the table got
	     moved far from original jump.  */
	  if (GET_CODE (PATTERN (insn)) == ADDR_VEC
	      || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
	    {
	      /* Avoid copying following barrier as well if any
		 (and debug insns in between).  */
	      rtx next;

	      for (next = NEXT_INSN (insn);
		   next != NEXT_INSN (to);
		   next = NEXT_INSN (next))
		if (!DEBUG_INSN_P (next))
		  break;
	      if (next != NEXT_INSN (to) && BARRIER_P (next))
		insn = next;
	      break;
	    }
	  copy = emit_copy_of_insn_after (insn, get_last_insn ());
          maybe_copy_prologue_epilogue_insn (insn, copy);
	  break;

	case CODE_LABEL:
	  break;

	case BARRIER:
	  emit_barrier ();
	  break;

	case NOTE:
	  switch (NOTE_KIND (insn))
	    {
	      /* In case prologue is empty and function contain label
		 in first BB, we may want to copy the block.  */
	    case NOTE_INSN_PROLOGUE_END:

	    case NOTE_INSN_DELETED:
	    case NOTE_INSN_DELETED_LABEL:
	      /* No problem to strip these.  */
	    case NOTE_INSN_FUNCTION_BEG:
	      /* There is always just single entry to function.  */
	    case NOTE_INSN_BASIC_BLOCK:
	      break;

	    case NOTE_INSN_EPILOGUE_BEG:
	    case NOTE_INSN_SWITCH_TEXT_SECTIONS:
	      emit_note_copy (insn);
	      break;

	    default:
	      /* All other notes should have already been eliminated.  */
	      gcc_unreachable ();
	    }
	  break;
	default:
	  gcc_unreachable ();
	}
    }
  insn = NEXT_INSN (last);
  delete_insn (last);
  return insn;
}
/* Create a duplicate of the basic block BB.  */

/* We do not want to declare the function in a header file, since it should
   only be used through the cfghooks interface, and we do not want to move
   it to cfgrtl.c since it would require also moving quite a lot of related
   code.  */
extern basic_block cfg_layout_duplicate_bb (basic_block);

basic_block
cfg_layout_duplicate_bb (basic_block bb)
{
  rtx insn;
  basic_block new_bb;

  insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb));
  new_bb = create_basic_block (insn,
			       insn ? get_last_insn () : NULL,
			       EXIT_BLOCK_PTR->prev_bb);

  BB_COPY_PARTITION (new_bb, bb);
  if (bb->il.rtl->header)
    {
      insn = bb->il.rtl->header;
      while (NEXT_INSN (insn))
	insn = NEXT_INSN (insn);
      insn = duplicate_insn_chain (bb->il.rtl->header, insn);
      if (insn)
	new_bb->il.rtl->header = unlink_insn_chain (insn, get_last_insn ());
    }

  if (bb->il.rtl->footer)
    {
      insn = bb->il.rtl->footer;
      while (NEXT_INSN (insn))
	insn = NEXT_INSN (insn);
      insn = duplicate_insn_chain (bb->il.rtl->footer, insn);
      if (insn)
	new_bb->il.rtl->footer = unlink_insn_chain (insn, get_last_insn ());
    }

  return new_bb;
}


/* Main entry point to this module - initialize the datastructures for
   CFG layout changes.  It keeps LOOPS up-to-date if not null.

   FLAGS is a set of additional flags to pass to cleanup_cfg().  */

void
cfg_layout_initialize (unsigned int flags)
{
  rtx x;
  basic_block bb;

  initialize_original_copy_tables ();

  cfg_layout_rtl_register_cfg_hooks ();

  record_effective_endpoints ();

  /* Make sure that the targets of non local gotos are marked.  */
  for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
    {
      bb = BLOCK_FOR_INSN (XEXP (x, 0));
      bb->flags |= BB_NON_LOCAL_GOTO_TARGET;
    }

  cleanup_cfg (CLEANUP_CFGLAYOUT | flags);
}

/* Splits superblocks.  */
void
break_superblocks (void)
{
  sbitmap superblocks;
  bool need = false;
  basic_block bb;

  superblocks = sbitmap_alloc (last_basic_block);
  sbitmap_zero (superblocks);

  FOR_EACH_BB (bb)
    if (bb->flags & BB_SUPERBLOCK)
      {
	bb->flags &= ~BB_SUPERBLOCK;
	SET_BIT (superblocks, bb->index);
	need = true;
      }

  if (need)
    {
      rebuild_jump_labels (get_insns ());
      find_many_sub_basic_blocks (superblocks);
    }

  free (superblocks);
}

/* Finalize the changes: reorder insn list according to the sequence specified
   by aux pointers, enter compensation code, rebuild scope forest.  */

void
cfg_layout_finalize (void)
{
#ifdef ENABLE_CHECKING
  verify_flow_info ();
#endif
  force_one_exit_fallthru ();
  rtl_register_cfg_hooks ();
  if (reload_completed
#ifdef HAVE_epilogue
      && !HAVE_epilogue
#endif
      )
    fixup_fallthru_exit_predecessor ();
  fixup_reorder_chain ();

  rebuild_jump_labels (get_insns ());
  delete_dead_jumptables ();

#ifdef ENABLE_CHECKING
  verify_insn_chain ();
  verify_flow_info ();
#endif
}

/* Checks whether all N blocks in BBS array can be copied.  */
bool
can_copy_bbs_p (basic_block *bbs, unsigned n)
{
  unsigned i;
  edge e;
  int ret = true;

  for (i = 0; i < n; i++)
    bbs[i]->flags |= BB_DUPLICATED;

  for (i = 0; i < n; i++)
    {
      /* In case we should redirect abnormal edge during duplication, fail.  */
      edge_iterator ei;
      FOR_EACH_EDGE (e, ei, bbs[i]->succs)
	if ((e->flags & EDGE_ABNORMAL)
	    && (e->dest->flags & BB_DUPLICATED))
	  {
	    ret = false;
	    goto end;
	  }

      if (!can_duplicate_block_p (bbs[i]))
	{
	  ret = false;
	  break;
	}
    }

end:
  for (i = 0; i < n; i++)
    bbs[i]->flags &= ~BB_DUPLICATED;

  return ret;
}

/* Duplicates N basic blocks stored in array BBS.  Newly created basic blocks
   are placed into array NEW_BBS in the same order.  Edges from basic blocks
   in BBS are also duplicated and copies of those of them
   that lead into BBS are redirected to appropriate newly created block.  The
   function assigns bbs into loops (copy of basic block bb is assigned to
   bb->loop_father->copy loop, so this must be set up correctly in advance)
   and updates dominators locally (LOOPS structure that contains the information
   about dominators is passed to enable this).

   BASE is the superloop to that basic block belongs; if its header or latch
   is copied, we do not set the new blocks as header or latch.

   Created copies of N_EDGES edges in array EDGES are stored in array NEW_EDGES,
   also in the same order.

   Newly created basic blocks are put after the basic block AFTER in the
   instruction stream, and the order of the blocks in BBS array is preserved.  */

void
copy_bbs (basic_block *bbs, unsigned n, basic_block *new_bbs,
	  edge *edges, unsigned num_edges, edge *new_edges,
	  struct loop *base, basic_block after)
{
  unsigned i, j;
  basic_block bb, new_bb, dom_bb;
  edge e;

  /* Duplicate bbs, update dominators, assign bbs to loops.  */
  for (i = 0; i < n; i++)
    {
      /* Duplicate.  */
      bb = bbs[i];
      new_bb = new_bbs[i] = duplicate_block (bb, NULL, after);
      after = new_bb;
      bb->flags |= BB_DUPLICATED;
      /* Possibly set loop header.  */
      if (bb->loop_father->header == bb && bb->loop_father != base)
	new_bb->loop_father->header = new_bb;
      /* Or latch.  */
      if (bb->loop_father->latch == bb && bb->loop_father != base)
	new_bb->loop_father->latch = new_bb;
    }

  /* Set dominators.  */
  for (i = 0; i < n; i++)
    {
      bb = bbs[i];
      new_bb = new_bbs[i];

      dom_bb = get_immediate_dominator (CDI_DOMINATORS, bb);
      if (dom_bb->flags & BB_DUPLICATED)
	{
	  dom_bb = get_bb_copy (dom_bb);
	  set_immediate_dominator (CDI_DOMINATORS, new_bb, dom_bb);
	}
    }

  /* Redirect edges.  */
  for (j = 0; j < num_edges; j++)
    new_edges[j] = NULL;
  for (i = 0; i < n; i++)
    {
      edge_iterator ei;
      new_bb = new_bbs[i];
      bb = bbs[i];

      FOR_EACH_EDGE (e, ei, new_bb->succs)
	{
	  for (j = 0; j < num_edges; j++)
	    if (edges[j] && edges[j]->src == bb && edges[j]->dest == e->dest)
	      new_edges[j] = e;

	  if (!(e->dest->flags & BB_DUPLICATED))
	    continue;
	  redirect_edge_and_branch_force (e, get_bb_copy (e->dest));
	}
    }

  /* Clear information about duplicates.  */
  for (i = 0; i < n; i++)
    bbs[i]->flags &= ~BB_DUPLICATED;
}

#include "gt-cfglayout.h"