aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.9/gcc/tree-ssa.c
blob: d835bc121f6a5618cf62d07051741406d2b4846c (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
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
/* Miscellaneous SSA utility functions.
   Copyright (C) 2001-2014 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 "stor-layout.h"
#include "flags.h"
#include "tm_p.h"
#include "target.h"
#include "langhooks.h"
#include "basic-block.h"
#include "function.h"
#include "gimple-pretty-print.h"
#include "pointer-set.h"
#include "tree-ssa-alias.h"
#include "internal-fn.h"
#include "gimple-fold.h"
#include "gimple-expr.h"
#include "is-a.h"
#include "gimple.h"
#include "gimplify.h"
#include "gimple-iterator.h"
#include "gimple-walk.h"
#include "gimple-ssa.h"
#include "tree-phinodes.h"
#include "ssa-iterators.h"
#include "stringpool.h"
#include "tree-ssanames.h"
#include "tree-ssa-loop-manip.h"
#include "tree-into-ssa.h"
#include "tree-ssa.h"
#include "tree-inline.h"
#include "hashtab.h"
#include "tree-pass.h"
#include "diagnostic-core.h"
#include "l-ipo.h"
#include "cfgloop.h"
#include "cfgexpand.h"

/* Pointer map of variable mappings, keyed by edge.  */
static struct pointer_map_t *edge_var_maps;


/* Add a mapping with PHI RESULT and PHI DEF associated with edge E.  */

void
redirect_edge_var_map_add (edge e, tree result, tree def, source_location locus)
{
  void **slot;
  edge_var_map_vector *head;
  edge_var_map new_node;

  if (edge_var_maps == NULL)
    edge_var_maps = pointer_map_create ();

  slot = pointer_map_insert (edge_var_maps, e);
  head = (edge_var_map_vector *) *slot;
  if (!head)
    vec_safe_reserve (head, 5);
  new_node.def = def;
  new_node.result = result;
  new_node.locus = locus;

  vec_safe_push (head, new_node);
  *slot = head;
}


/* Clear the var mappings in edge E.  */

void
redirect_edge_var_map_clear (edge e)
{
  void **slot;
  edge_var_map_vector *head;

  if (!edge_var_maps)
    return;

  slot = pointer_map_contains (edge_var_maps, e);

  if (slot)
    {
      head = (edge_var_map_vector *) *slot;
      vec_free (head);
      *slot = NULL;
    }
}


/* Duplicate the redirected var mappings in OLDE in NEWE.

   Since we can't remove a mapping, let's just duplicate it.  This assumes a
   pointer_map can have multiple edges mapping to the same var_map (many to
   one mapping), since we don't remove the previous mappings.  */

void
redirect_edge_var_map_dup (edge newe, edge olde)
{
  void **new_slot, **old_slot;
  edge_var_map_vector *head;

  if (!edge_var_maps)
    return;

  new_slot = pointer_map_insert (edge_var_maps, newe);
  old_slot = pointer_map_contains (edge_var_maps, olde);
  if (!old_slot)
    return;
  head = (edge_var_map_vector *) *old_slot;

  edge_var_map_vector *new_head = NULL;
  if (head)
    new_head = vec_safe_copy (head);
  else
    vec_safe_reserve (new_head, 5);
  *new_slot = new_head;
}


/* Return the variable mappings for a given edge.  If there is none, return
   NULL.  */

edge_var_map_vector *
redirect_edge_var_map_vector (edge e)
{
  void **slot;

  /* Hey, what kind of idiot would... you'd be surprised.  */
  if (!edge_var_maps)
    return NULL;

  slot = pointer_map_contains (edge_var_maps, e);
  if (!slot)
    return NULL;

  return (edge_var_map_vector *) *slot;
}

/* Used by redirect_edge_var_map_destroy to free all memory.  */

static bool
free_var_map_entry (const void *key ATTRIBUTE_UNUSED,
		    void **value,
		    void *data ATTRIBUTE_UNUSED)
{
  edge_var_map_vector *head = (edge_var_map_vector *) *value;
  vec_free (head);
  return true;
}

/* Clear the edge variable mappings.  */

void
redirect_edge_var_map_destroy (void)
{
  if (edge_var_maps)
    {
      pointer_map_traverse (edge_var_maps, free_var_map_entry, NULL);
      pointer_map_destroy (edge_var_maps);
      edge_var_maps = NULL;
    }
}


/* Remove the corresponding arguments from the PHI nodes in E's
   destination block and redirect it to DEST.  Return redirected edge.
   The list of removed arguments is stored in a vector accessed
   through edge_var_maps.  */

edge
ssa_redirect_edge (edge e, basic_block dest)
{
  gimple_stmt_iterator gsi;
  gimple phi;

  redirect_edge_var_map_clear (e);

  /* Remove the appropriate PHI arguments in E's destination block.  */
  for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      tree def;
      source_location locus ;

      phi = gsi_stmt (gsi);
      def = gimple_phi_arg_def (phi, e->dest_idx);
      locus = gimple_phi_arg_location (phi, e->dest_idx);

      if (def == NULL_TREE)
	continue;

      redirect_edge_var_map_add (e, gimple_phi_result (phi), def, locus);
    }

  e = redirect_edge_succ_nodup (e, dest);

  return e;
}


/* Add PHI arguments queued in PENDING_STMT list on edge E to edge
   E->dest.  */

void
flush_pending_stmts (edge e)
{
  gimple phi;
  edge_var_map_vector *v;
  edge_var_map *vm;
  int i;
  gimple_stmt_iterator gsi;

  v = redirect_edge_var_map_vector (e);
  if (!v)
    return;

  for (gsi = gsi_start_phis (e->dest), i = 0;
       !gsi_end_p (gsi) && v->iterate (i, &vm);
       gsi_next (&gsi), i++)
    {
      tree def;

      phi = gsi_stmt (gsi);
      def = redirect_edge_var_map_def (vm);
      add_phi_arg (phi, def, e, redirect_edge_var_map_location (vm));
    }

  redirect_edge_var_map_clear (e);
}

/* Replace the LHS of STMT, an assignment, either a GIMPLE_ASSIGN or a
   GIMPLE_CALL, with NLHS, in preparation for modifying the RHS to an
   expression with a different value.

   This will update any annotations (say debug bind stmts) referring
   to the original LHS, so that they use the RHS instead.  This is
   done even if NLHS and LHS are the same, for it is understood that
   the RHS will be modified afterwards, and NLHS will not be assigned
   an equivalent value.

   Adjusting any non-annotation uses of the LHS, if needed, is a
   responsibility of the caller.

   The effect of this call should be pretty much the same as that of
   inserting a copy of STMT before STMT, and then removing the
   original stmt, at which time gsi_remove() would have update
   annotations, but using this function saves all the inserting,
   copying and removing.  */

void
gimple_replace_ssa_lhs (gimple stmt, tree nlhs)
{
  if (MAY_HAVE_DEBUG_STMTS)
    {
      tree lhs = gimple_get_lhs (stmt);

      gcc_assert (SSA_NAME_DEF_STMT (lhs) == stmt);

      insert_debug_temp_for_var_def (NULL, lhs);
    }

  gimple_set_lhs (stmt, nlhs);
}


/* Given a tree for an expression for which we might want to emit
   locations or values in debug information (generally a variable, but
   we might deal with other kinds of trees in the future), return the
   tree that should be used as the variable of a DEBUG_BIND STMT or
   VAR_LOCATION INSN or NOTE.  Return NULL if VAR is not to be tracked.  */

tree
target_for_debug_bind (tree var)
{
  if (!MAY_HAVE_DEBUG_STMTS)
    return NULL_TREE;

  if (TREE_CODE (var) == SSA_NAME)
    {
      var = SSA_NAME_VAR (var);
      if (var == NULL_TREE)
	return NULL_TREE;
    }

  if ((TREE_CODE (var) != VAR_DECL
       || VAR_DECL_IS_VIRTUAL_OPERAND (var))
      && TREE_CODE (var) != PARM_DECL)
    return NULL_TREE;

  if (DECL_HAS_VALUE_EXPR_P (var))
    return target_for_debug_bind (DECL_VALUE_EXPR (var));

  if (DECL_IGNORED_P (var))
    return NULL_TREE;

  /* var-tracking only tracks registers.  */
  if (!is_gimple_reg_type (TREE_TYPE (var)))
    return NULL_TREE;

  return var;
}

/* Called via walk_tree, look for SSA_NAMEs that have already been
   released.  */

static tree
find_released_ssa_name (tree *tp, int *walk_subtrees, void *data_)
{
  struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;

  if (wi && wi->is_lhs)
    return NULL_TREE;

  if (TREE_CODE (*tp) == SSA_NAME)
    {
      if (SSA_NAME_IN_FREE_LIST (*tp))
	return *tp;

      *walk_subtrees = 0;
    }
  else if (IS_TYPE_OR_DECL_P (*tp))
    *walk_subtrees = 0;

  return NULL_TREE;
}

/* Insert a DEBUG BIND stmt before the DEF of VAR if VAR is referenced
   by other DEBUG stmts, and replace uses of the DEF with the
   newly-created debug temp.  */

void
insert_debug_temp_for_var_def (gimple_stmt_iterator *gsi, tree var)
{
  imm_use_iterator imm_iter;
  use_operand_p use_p;
  gimple stmt;
  gimple def_stmt = NULL;
  int usecount = 0;
  tree value = NULL;

  if (!MAY_HAVE_DEBUG_STMTS)
    return;

  /* If this name has already been registered for replacement, do nothing
     as anything that uses this name isn't in SSA form.  */
  if (name_registered_for_update_p (var))
    return;

  /* Check whether there are debug stmts that reference this variable and,
     if there are, decide whether we should use a debug temp.  */
  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
    {
      stmt = USE_STMT (use_p);

      if (!gimple_debug_bind_p (stmt))
	continue;

      if (usecount++)
	break;

      if (gimple_debug_bind_get_value (stmt) != var)
	{
	  /* Count this as an additional use, so as to make sure we
	     use a temp unless VAR's definition has a SINGLE_RHS that
	     can be shared.  */
	  usecount++;
	  break;
	}
    }

  if (!usecount)
    return;

  if (gsi)
    def_stmt = gsi_stmt (*gsi);
  else
    def_stmt = SSA_NAME_DEF_STMT (var);

  /* If we didn't get an insertion point, and the stmt has already
     been removed, we won't be able to insert the debug bind stmt, so
     we'll have to drop debug information.  */
  if (gimple_code (def_stmt) == GIMPLE_PHI)
    {
      value = degenerate_phi_result (def_stmt);
      if (value && walk_tree (&value, find_released_ssa_name, NULL, NULL))
	value = NULL;
      /* error_mark_node is what fixup_noreturn_call changes PHI arguments
	 to.  */
      else if (value == error_mark_node)
	value = NULL;
    }
  else if (is_gimple_assign (def_stmt))
    {
      bool no_value = false;

      if (!dom_info_available_p (CDI_DOMINATORS))
	{
	  struct walk_stmt_info wi;

	  memset (&wi, 0, sizeof (wi));

	  /* When removing blocks without following reverse dominance
	     order, we may sometimes encounter SSA_NAMEs that have
	     already been released, referenced in other SSA_DEFs that
	     we're about to release.  Consider:

	     <bb X>:
	     v_1 = foo;

	     <bb Y>:
	     w_2 = v_1 + bar;
	     # DEBUG w => w_2

	     If we deleted BB X first, propagating the value of w_2
	     won't do us any good.  It's too late to recover their
	     original definition of v_1: when it was deleted, it was
	     only referenced in other DEFs, it couldn't possibly know
	     it should have been retained, and propagating every
	     single DEF just in case it might have to be propagated
	     into a DEBUG STMT would probably be too wasteful.

	     When dominator information is not readily available, we
	     check for and accept some loss of debug information.  But
	     if it is available, there's no excuse for us to remove
	     blocks in the wrong order, so we don't even check for
	     dead SSA NAMEs.  SSA verification shall catch any
	     errors.  */
	  if ((!gsi && !gimple_bb (def_stmt))
	      || walk_gimple_op (def_stmt, find_released_ssa_name, &wi))
	    no_value = true;
	}

      if (!no_value)
	value = gimple_assign_rhs_to_tree (def_stmt);
    }

  if (value)
    {
      /* If there's a single use of VAR, and VAR is the entire debug
	 expression (usecount would have been incremented again
	 otherwise), and the definition involves only constants and
	 SSA names, then we can propagate VALUE into this single use,
	 avoiding the temp.

	 We can also avoid using a temp if VALUE can be shared and
	 propagated into all uses, without generating expressions that
	 wouldn't be valid gimple RHSs.

	 Other cases that would require unsharing or non-gimple RHSs
	 are deferred to a debug temp, although we could avoid temps
	 at the expense of duplication of expressions.  */

      if (CONSTANT_CLASS_P (value)
	  || gimple_code (def_stmt) == GIMPLE_PHI
	  || (usecount == 1
	      && (!gimple_assign_single_p (def_stmt)
		  || is_gimple_min_invariant (value)))
	  || is_gimple_reg (value))
	;
      else
	{
	  gimple def_temp;
	  tree vexpr = make_node (DEBUG_EXPR_DECL);

	  def_temp = gimple_build_debug_bind (vexpr,
					      unshare_expr (value),
					      def_stmt);

	  DECL_ARTIFICIAL (vexpr) = 1;
	  TREE_TYPE (vexpr) = TREE_TYPE (value);
	  if (DECL_P (value))
	    DECL_MODE (vexpr) = DECL_MODE (value);
	  else
	    DECL_MODE (vexpr) = TYPE_MODE (TREE_TYPE (value));

	  if (gsi)
	    gsi_insert_before (gsi, def_temp, GSI_SAME_STMT);
	  else
	    {
	      gimple_stmt_iterator ngsi = gsi_for_stmt (def_stmt);
	      gsi_insert_before (&ngsi, def_temp, GSI_SAME_STMT);
	    }

	  value = vexpr;
	}
    }

  FOR_EACH_IMM_USE_STMT (stmt, imm_iter, var)
    {
      if (!gimple_debug_bind_p (stmt))
	continue;

      if (value)
	{
	  FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
	    /* unshare_expr is not needed here.  vexpr is either a
	       SINGLE_RHS, that can be safely shared, some other RHS
	       that was unshared when we found it had a single debug
	       use, or a DEBUG_EXPR_DECL, that can be safely
	       shared.  */
	    SET_USE (use_p, unshare_expr (value));
	  /* If we didn't replace uses with a debug decl fold the
	     resulting expression.  Otherwise we end up with invalid IL.  */
	  if (TREE_CODE (value) != DEBUG_EXPR_DECL)
	    {
	      gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
	      fold_stmt_inplace (&gsi);
	    }
	}
      else
	gimple_debug_bind_reset_value (stmt);

      update_stmt (stmt);
    }
}


/* Insert a DEBUG BIND stmt before STMT for each DEF referenced by
   other DEBUG stmts, and replace uses of the DEF with the
   newly-created debug temp.  */

void
insert_debug_temps_for_defs (gimple_stmt_iterator *gsi)
{
  gimple stmt;
  ssa_op_iter op_iter;
  def_operand_p def_p;

  if (!MAY_HAVE_DEBUG_STMTS)
    return;

  stmt = gsi_stmt (*gsi);

  FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
    {
      tree var = DEF_FROM_PTR (def_p);

      if (TREE_CODE (var) != SSA_NAME)
	continue;

      insert_debug_temp_for_var_def (gsi, var);
    }
}

/* Reset all debug stmts that use SSA_NAME(s) defined in STMT.  */

void
reset_debug_uses (gimple stmt)
{
  ssa_op_iter op_iter;
  def_operand_p def_p;
  imm_use_iterator imm_iter;
  gimple use_stmt;

  if (!MAY_HAVE_DEBUG_STMTS)
    return;

  FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
    {
      tree var = DEF_FROM_PTR (def_p);

      if (TREE_CODE (var) != SSA_NAME)
	continue;

      FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, var)
	{
	  if (!gimple_debug_bind_p (use_stmt))
	    continue;

	  gimple_debug_bind_reset_value (use_stmt);
	  update_stmt (use_stmt);
	}
    }
}

/* Delete SSA DEFs for SSA versions in the TOREMOVE bitmap, removing
   dominated stmts before their dominators, so that release_ssa_defs
   stands a chance of propagating DEFs into debug bind stmts.  */

void
release_defs_bitset (bitmap toremove)
{
  unsigned j;
  bitmap_iterator bi;

  /* Performing a topological sort is probably overkill, this will
     most likely run in slightly superlinear time, rather than the
     pathological quadratic worst case.  */
  while (!bitmap_empty_p (toremove))
    EXECUTE_IF_SET_IN_BITMAP (toremove, 0, j, bi)
      {
	bool remove_now = true;
	tree var = ssa_name (j);
	gimple stmt;
	imm_use_iterator uit;

	FOR_EACH_IMM_USE_STMT (stmt, uit, var)
	  {
	    ssa_op_iter dit;
	    def_operand_p def_p;

	    /* We can't propagate PHI nodes into debug stmts.  */
	    if (gimple_code (stmt) == GIMPLE_PHI
		|| is_gimple_debug (stmt))
	      continue;

	    /* If we find another definition to remove that uses
	       the one we're looking at, defer the removal of this
	       one, so that it can be propagated into debug stmts
	       after the other is.  */
	    FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, dit, SSA_OP_DEF)
	      {
		tree odef = DEF_FROM_PTR (def_p);

		if (bitmap_bit_p (toremove, SSA_NAME_VERSION (odef)))
		  {
		    remove_now = false;
		    break;
		  }
	      }

	    if (!remove_now)
	      BREAK_FROM_IMM_USE_STMT (uit);
	  }

	if (remove_now)
	  {
	    gimple def = SSA_NAME_DEF_STMT (var);
	    gimple_stmt_iterator gsi = gsi_for_stmt (def);

	    if (gimple_code (def) == GIMPLE_PHI)
	      remove_phi_node (&gsi, true);
	    else
	      {
		gsi_remove (&gsi, true);
		release_defs (def);
	      }

	    bitmap_clear_bit (toremove, j);
	  }
      }
}

/* Return true if SSA_NAME is malformed and mark it visited.

   IS_VIRTUAL is true if this SSA_NAME was found inside a virtual
      operand.  */

static bool
verify_ssa_name (tree ssa_name, bool is_virtual)
{
  if (TREE_CODE (ssa_name) != SSA_NAME)
    {
      error ("expected an SSA_NAME object");
      return true;
    }

  if (SSA_NAME_IN_FREE_LIST (ssa_name))
    {
      error ("found an SSA_NAME that had been released into the free pool");
      return true;
    }

  if (SSA_NAME_VAR (ssa_name) != NULL_TREE
      && TREE_TYPE (ssa_name) != TREE_TYPE (SSA_NAME_VAR (ssa_name)))
    {
      error ("type mismatch between an SSA_NAME and its symbol");
      return true;
    }

  if (is_virtual && !virtual_operand_p (ssa_name))
    {
      error ("found a virtual definition for a GIMPLE register");
      return true;
    }

  if (is_virtual && SSA_NAME_VAR (ssa_name) != gimple_vop (cfun))
    {
      error ("virtual SSA name for non-VOP decl");
      return true;
    }

  if (!is_virtual && virtual_operand_p (ssa_name))
    {
      error ("found a real definition for a non-register");
      return true;
    }

  if (SSA_NAME_IS_DEFAULT_DEF (ssa_name)
      && !gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name)))
    {
      error ("found a default name with a non-empty defining statement");
      return true;
    }

  return false;
}


/* Return true if the definition of SSA_NAME at block BB is malformed.

   STMT is the statement where SSA_NAME is created.

   DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
      version numbers.  If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
      it means that the block in that array slot contains the
      definition of SSA_NAME.

   IS_VIRTUAL is true if SSA_NAME is created by a VDEF.  */

static bool
verify_def (basic_block bb, basic_block *definition_block, tree ssa_name,
	    gimple stmt, bool is_virtual)
{
  if (verify_ssa_name (ssa_name, is_virtual))
    goto err;

  if (SSA_NAME_VAR (ssa_name)
      && TREE_CODE (SSA_NAME_VAR (ssa_name)) == RESULT_DECL
      && DECL_BY_REFERENCE (SSA_NAME_VAR (ssa_name)))
    {
      error ("RESULT_DECL should be read only when DECL_BY_REFERENCE is set");
      goto err;
    }

  if (definition_block[SSA_NAME_VERSION (ssa_name)])
    {
      error ("SSA_NAME created in two different blocks %i and %i",
	     definition_block[SSA_NAME_VERSION (ssa_name)]->index, bb->index);
      goto err;
    }

  definition_block[SSA_NAME_VERSION (ssa_name)] = bb;

  if (SSA_NAME_DEF_STMT (ssa_name) != stmt)
    {
      error ("SSA_NAME_DEF_STMT is wrong");
      fprintf (stderr, "Expected definition statement:\n");
      print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (ssa_name), 4, TDF_VOPS);
      fprintf (stderr, "\nActual definition statement:\n");
      print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
      goto err;
    }

  return false;

err:
  fprintf (stderr, "while verifying SSA_NAME ");
  print_generic_expr (stderr, ssa_name, 0);
  fprintf (stderr, " in statement\n");
  print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);

  return true;
}


/* Return true if the use of SSA_NAME at statement STMT in block BB is
   malformed.

   DEF_BB is the block where SSA_NAME was found to be created.

   IDOM contains immediate dominator information for the flowgraph.

   CHECK_ABNORMAL is true if the caller wants to check whether this use
      is flowing through an abnormal edge (only used when checking PHI
      arguments).

   If NAMES_DEFINED_IN_BB is not NULL, it contains a bitmap of ssa names
     that are defined before STMT in basic block BB.  */

static bool
verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p,
	    gimple stmt, bool check_abnormal, bitmap names_defined_in_bb)
{
  bool err = false;
  tree ssa_name = USE_FROM_PTR (use_p);

  if (!TREE_VISITED (ssa_name))
    if (verify_imm_links (stderr, ssa_name))
      err = true;

  TREE_VISITED (ssa_name) = 1;

  if (gimple_nop_p (SSA_NAME_DEF_STMT (ssa_name))
      && SSA_NAME_IS_DEFAULT_DEF (ssa_name))
    ; /* Default definitions have empty statements.  Nothing to do.  */
  else if (!def_bb)
    {
      error ("missing definition");
      err = true;
    }
  else if (bb != def_bb
	   && !dominated_by_p (CDI_DOMINATORS, bb, def_bb))
    {
      error ("definition in block %i does not dominate use in block %i",
	     def_bb->index, bb->index);
      err = true;
    }
  else if (bb == def_bb
	   && names_defined_in_bb != NULL
	   && !bitmap_bit_p (names_defined_in_bb, SSA_NAME_VERSION (ssa_name)))
    {
      error ("definition in block %i follows the use", def_bb->index);
      err = true;
    }

  if (check_abnormal
      && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssa_name))
    {
      error ("SSA_NAME_OCCURS_IN_ABNORMAL_PHI should be set");
      err = true;
    }

  /* Make sure the use is in an appropriate list by checking the previous
     element to make sure it's the same.  */
  if (use_p->prev == NULL)
    {
      error ("no immediate_use list");
      err = true;
    }
  else
    {
      tree listvar;
      if (use_p->prev->use == NULL)
	listvar = use_p->prev->loc.ssa_name;
      else
	listvar = USE_FROM_PTR (use_p->prev);
      if (listvar != ssa_name)
        {
	  error ("wrong immediate use list");
	  err = true;
	}
    }

  if (err)
    {
      fprintf (stderr, "for SSA_NAME: ");
      print_generic_expr (stderr, ssa_name, TDF_VOPS);
      fprintf (stderr, " in statement:\n");
      print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
    }

  return err;
}


/* Return true if any of the arguments for PHI node PHI at block BB is
   malformed.

   DEFINITION_BLOCK is an array of basic blocks indexed by SSA_NAME
      version numbers.  If DEFINITION_BLOCK[SSA_NAME_VERSION] is set,
      it means that the block in that array slot contains the
      definition of SSA_NAME.  */

static bool
verify_phi_args (gimple phi, basic_block bb, basic_block *definition_block)
{
  edge e;
  bool err = false;
  size_t i, phi_num_args = gimple_phi_num_args (phi);

  if (EDGE_COUNT (bb->preds) != phi_num_args)
    {
      error ("incoming edge count does not match number of PHI arguments");
      err = true;
      goto error;
    }

  for (i = 0; i < phi_num_args; i++)
    {
      use_operand_p op_p = gimple_phi_arg_imm_use_ptr (phi, i);
      tree op = USE_FROM_PTR (op_p);

      e = EDGE_PRED (bb, i);

      if (op == NULL_TREE)
	{
	  error ("PHI argument is missing for edge %d->%d",
	         e->src->index,
		 e->dest->index);
	  err = true;
	  goto error;
	}

      if (TREE_CODE (op) != SSA_NAME && !is_gimple_min_invariant (op))
	{
	  error ("PHI argument is not SSA_NAME, or invariant");
	  err = true;
	}

      if (TREE_CODE (op) == SSA_NAME)
	{
	  err = verify_ssa_name (op, virtual_operand_p (gimple_phi_result (phi)));
	  err |= verify_use (e->src, definition_block[SSA_NAME_VERSION (op)],
			     op_p, phi, e->flags & EDGE_ABNORMAL, NULL);
	}

      if (TREE_CODE (op) == ADDR_EXPR)
	{
	  tree base = TREE_OPERAND (op, 0);
	  while (handled_component_p (base))
	    base = TREE_OPERAND (base, 0);
	  if ((TREE_CODE (base) == VAR_DECL
	       || TREE_CODE (base) == PARM_DECL
	       || TREE_CODE (base) == RESULT_DECL)
	      && !TREE_ADDRESSABLE (base))
	    {
	      error ("address taken, but ADDRESSABLE bit not set");
	      err = true;
	    }
	}

      if (e->dest != bb)
	{
	  error ("wrong edge %d->%d for PHI argument",
	         e->src->index, e->dest->index);
	  err = true;
	}

      if (err)
	{
	  fprintf (stderr, "PHI argument\n");
	  print_generic_stmt (stderr, op, TDF_VOPS);
	  goto error;
	}
    }

error:
  if (err)
    {
      fprintf (stderr, "for PHI node\n");
      print_gimple_stmt (stderr, phi, 0, TDF_VOPS|TDF_MEMSYMS);
    }


  return err;
}


/* Verify common invariants in the SSA web.
   TODO: verify the variable annotations.  */

DEBUG_FUNCTION void
verify_ssa (bool check_modified_stmt)
{
  size_t i;
  basic_block bb;
  basic_block *definition_block = XCNEWVEC (basic_block, num_ssa_names);
  ssa_op_iter iter;
  tree op;
  enum dom_state orig_dom_state = dom_info_state (CDI_DOMINATORS);
  bitmap names_defined_in_bb = BITMAP_ALLOC (NULL);

  gcc_assert (!need_ssa_update_p (cfun));

  timevar_push (TV_TREE_SSA_VERIFY);

  /* Keep track of SSA names present in the IL.  */
  for (i = 1; i < num_ssa_names; i++)
    {
      tree name = ssa_name (i);
      if (name)
	{
	  gimple stmt;
	  TREE_VISITED (name) = 0;

	  verify_ssa_name (name, virtual_operand_p (name));

	  stmt = SSA_NAME_DEF_STMT (name);
	  if (!gimple_nop_p (stmt))
	    {
	      basic_block bb = gimple_bb (stmt);
	      if (verify_def (bb, definition_block,
			      name, stmt, virtual_operand_p (name)))
		goto err;
	    }
	}
    }

  calculate_dominance_info (CDI_DOMINATORS);

  /* Now verify all the uses and make sure they agree with the definitions
     found in the previous pass.  */
  FOR_EACH_BB_FN (bb, cfun)
    {
      edge e;
      gimple phi;
      edge_iterator ei;
      gimple_stmt_iterator gsi;

      /* Make sure that all edges have a clear 'aux' field.  */
      FOR_EACH_EDGE (e, ei, bb->preds)
	{
	  if (e->aux)
	    {
	      error ("AUX pointer initialized for edge %d->%d", e->src->index,
		      e->dest->index);
	      goto err;
	    }
	}

      /* Verify the arguments for every PHI node in the block.  */
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  phi = gsi_stmt (gsi);
	  if (verify_phi_args (phi, bb, definition_block))
	    goto err;

	  bitmap_set_bit (names_defined_in_bb,
			  SSA_NAME_VERSION (gimple_phi_result (phi)));
	}

      /* Now verify all the uses and vuses in every statement of the block.  */
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  gimple stmt = gsi_stmt (gsi);
	  use_operand_p use_p;

	  if (check_modified_stmt && gimple_modified_p (stmt))
	    {
	      error ("stmt (%p) marked modified after optimization pass: ",
		     (void *)stmt);
	      print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
	      goto err;
	    }

	  if (verify_ssa_operands (cfun, stmt))
	    {
	      print_gimple_stmt (stderr, stmt, 0, TDF_VOPS);
	      goto err;
	    }

	  if (gimple_debug_bind_p (stmt)
	      && !gimple_debug_bind_has_value_p (stmt))
	    continue;

	  FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE|SSA_OP_VUSE)
	    {
	      op = USE_FROM_PTR (use_p);
	      if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)],
			      use_p, stmt, false, names_defined_in_bb))
		goto err;
	    }

	  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS)
	    {
	      if (SSA_NAME_DEF_STMT (op) != stmt)
		{
		  error ("SSA_NAME_DEF_STMT is wrong");
		  fprintf (stderr, "Expected definition statement:\n");
		  print_gimple_stmt (stderr, stmt, 4, TDF_VOPS);
		  fprintf (stderr, "\nActual definition statement:\n");
		  print_gimple_stmt (stderr, SSA_NAME_DEF_STMT (op),
				     4, TDF_VOPS);
		  goto err;
		}
	      bitmap_set_bit (names_defined_in_bb, SSA_NAME_VERSION (op));
	    }
	}

      bitmap_clear (names_defined_in_bb);
    }

  free (definition_block);

  /* Restore the dominance information to its prior known state, so
     that we do not perturb the compiler's subsequent behavior.  */
  if (orig_dom_state == DOM_NONE)
    free_dominance_info (CDI_DOMINATORS);
  else
    set_dom_info_availability (CDI_DOMINATORS, orig_dom_state);

  BITMAP_FREE (names_defined_in_bb);
  timevar_pop (TV_TREE_SSA_VERIFY);
  return;

err:
  internal_error ("verify_ssa failed");
}

/* Return true if the DECL_UID in both trees are equal.  */

static int
uid_ssaname_map_eq (const void *va, const void *vb)
{
  const_tree a = (const_tree) va;
  const_tree b = (const_tree) vb;
  return (a->ssa_name.var->decl_minimal.uid == b->ssa_name.var->decl_minimal.uid);
}

/* Hash a tree in a uid_decl_map.  */

static unsigned int
uid_ssaname_map_hash (const void *item)
{
  return ((const_tree)item)->ssa_name.var->decl_minimal.uid;
}


/* Initialize global DFA and SSA structures.  */

void
init_tree_ssa (struct function *fn)
{
  fn->gimple_df = ggc_alloc_cleared_gimple_df ();
  fn->gimple_df->default_defs = htab_create_ggc (20, uid_ssaname_map_hash,
				                 uid_ssaname_map_eq, NULL);
  pt_solution_reset (&fn->gimple_df->escaped);
  init_ssanames (fn, 0);
}

/* Do the actions required to initialize internal data structures used
   in tree-ssa optimization passes.  */

static unsigned int
execute_init_datastructures (void)
{
  /* Allocate hash tables, arrays and other structures.  */
  gcc_assert (!cfun->gimple_df);
  init_tree_ssa (cfun);
  return 0;
}

/* Gate for IPCP optimization.  */

static bool
gate_init_datastructures (void)
{
  /* Do nothing for funcions that was produced already in SSA form.  */
  return !(cfun->curr_properties & PROP_ssa);
}

namespace {

const pass_data pass_data_init_datastructures =
{
  GIMPLE_PASS, /* type */
  "*init_datastructures", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  true, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  PROP_cfg, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  0, /* todo_flags_finish */
};

class pass_init_datastructures : public gimple_opt_pass
{
public:
  pass_init_datastructures (gcc::context *ctxt)
    : gimple_opt_pass (pass_data_init_datastructures, ctxt)
  {}

  /* opt_pass methods: */
  bool gate () { return gate_init_datastructures (); }
  unsigned int execute () { return execute_init_datastructures (); }

}; // class pass_init_datastructures

} // anon namespace

gimple_opt_pass *
make_pass_init_datastructures (gcc::context *ctxt)
{
  return new pass_init_datastructures (ctxt);
}

/* Deallocate memory associated with SSA data structures for FNDECL.  */

void
delete_tree_ssa (void)
{
  fini_ssanames ();

  /* We no longer maintain the SSA operand cache at this point.  */
  if (ssa_operands_active (cfun))
    fini_ssa_operands (cfun);

  htab_delete (cfun->gimple_df->default_defs);
  cfun->gimple_df->default_defs = NULL;
  pt_solution_reset (&cfun->gimple_df->escaped);
  if (cfun->gimple_df->decls_to_pointers != NULL)
    pointer_map_destroy (cfun->gimple_df->decls_to_pointers);
  cfun->gimple_df->decls_to_pointers = NULL;
  cfun->gimple_df->modified_noreturn_calls = NULL;
  cfun->gimple_df = NULL;

  /* We no longer need the edge variable maps.  */
  redirect_edge_var_map_destroy ();
}

/* Return true if EXPR is a useless type conversion, otherwise return
   false.  */

bool
tree_ssa_useless_type_conversion (tree expr)
{
  /* If we have an assignment that merely uses a NOP_EXPR to change
     the top of the RHS to the type of the LHS and the type conversion
     is "safe", then strip away the type conversion so that we can
     enter LHS = RHS into the const_and_copies table.  */
  if (CONVERT_EXPR_P (expr)
      || TREE_CODE (expr) == VIEW_CONVERT_EXPR
      || TREE_CODE (expr) == NON_LVALUE_EXPR)
    return useless_type_conversion_p
      (TREE_TYPE (expr),
       TREE_TYPE (TREE_OPERAND (expr, 0)));

  return false;
}

/* Strip conversions from EXP according to
   tree_ssa_useless_type_conversion and return the resulting
   expression.  */

tree
tree_ssa_strip_useless_type_conversions (tree exp)
{
  while (tree_ssa_useless_type_conversion (exp))
    exp = TREE_OPERAND (exp, 0);
  return exp;
}


/* Return true if T, an SSA_NAME, has an undefined value.  */

bool
ssa_undefined_value_p (tree t)
{
  tree var = SSA_NAME_VAR (t);

  if (!var)
    ;
  /* Parameters get their initial value from the function entry.  */
  else if (TREE_CODE (var) == PARM_DECL)
    return false;
  /* When returning by reference the return address is actually a hidden
     parameter.  */
  else if (TREE_CODE (var) == RESULT_DECL && DECL_BY_REFERENCE (var))
    return false;
  /* Hard register variables get their initial value from the ether.  */
  else if (TREE_CODE (var) == VAR_DECL && DECL_HARD_REGISTER (var))
    return false;

  /* The value is undefined iff its definition statement is empty.  */
  return gimple_nop_p (SSA_NAME_DEF_STMT (t));
}


/* If necessary, rewrite the base of the reference tree *TP from
   a MEM_REF to a plain or converted symbol.  */

static void
maybe_rewrite_mem_ref_base (tree *tp, bitmap suitable_for_renaming)
{
  tree sym;

  while (handled_component_p (*tp))
    tp = &TREE_OPERAND (*tp, 0);
  if (TREE_CODE (*tp) == MEM_REF
      && TREE_CODE (TREE_OPERAND (*tp, 0)) == ADDR_EXPR
      && (sym = TREE_OPERAND (TREE_OPERAND (*tp, 0), 0))
      && DECL_P (sym)
      && !TREE_ADDRESSABLE (sym)
      && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym)))
    {
      if (TREE_CODE (TREE_TYPE (sym)) == VECTOR_TYPE
	  && useless_type_conversion_p (TREE_TYPE (*tp),
					TREE_TYPE (TREE_TYPE (sym)))
	  && multiple_of_p (sizetype, TREE_OPERAND (*tp, 1),
			    TYPE_SIZE_UNIT (TREE_TYPE (*tp))))
	{
	  *tp = build3 (BIT_FIELD_REF, TREE_TYPE (*tp), sym, 
			TYPE_SIZE (TREE_TYPE (*tp)),
			int_const_binop (MULT_EXPR,
					 bitsize_int (BITS_PER_UNIT),
					 TREE_OPERAND (*tp, 1)));
	}
      else if (TREE_CODE (TREE_TYPE (sym)) == COMPLEX_TYPE
	       && useless_type_conversion_p (TREE_TYPE (*tp),
					     TREE_TYPE (TREE_TYPE (sym))))
	{
	  *tp = build1 (integer_zerop (TREE_OPERAND (*tp, 1))
			? REALPART_EXPR : IMAGPART_EXPR,
			TREE_TYPE (*tp), sym);
	}
      else if (integer_zerop (TREE_OPERAND (*tp, 1)))
	{
	  if (!useless_type_conversion_p (TREE_TYPE (*tp),
					  TREE_TYPE (sym)))
	    *tp = build1 (VIEW_CONVERT_EXPR,
			  TREE_TYPE (*tp), sym);
	  else
	    *tp = sym;
	}
    }
}

/* For a tree REF return its base if it is the base of a MEM_REF
   that cannot be rewritten into SSA form.  Otherwise return NULL_TREE.  */

static tree
non_rewritable_mem_ref_base (tree ref)
{
  tree base = ref;

  /* A plain decl does not need it set.  */
  if (DECL_P (ref))
    return NULL_TREE;

  while (handled_component_p (base))
    base = TREE_OPERAND (base, 0);

  /* But watch out for MEM_REFs we cannot lower to a
     VIEW_CONVERT_EXPR or a BIT_FIELD_REF.  */
  if (TREE_CODE (base) == MEM_REF
      && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
    {
      tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
      if ((TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE
	   || TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE)
	  && useless_type_conversion_p (TREE_TYPE (base),
					TREE_TYPE (TREE_TYPE (decl)))
	  && mem_ref_offset (base).fits_uhwi ()
	  && tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (decl)))
	     .ugt (mem_ref_offset (base))
	  && multiple_of_p (sizetype, TREE_OPERAND (base, 1),
			    TYPE_SIZE_UNIT (TREE_TYPE (base))))
	return NULL_TREE;
      if (DECL_P (decl)
	  && (!integer_zerop (TREE_OPERAND (base, 1))
	      || (DECL_SIZE (decl)
		  != TYPE_SIZE (TREE_TYPE (base)))
	      || TREE_THIS_VOLATILE (decl) != TREE_THIS_VOLATILE (base)))
	return decl;
    }

  return NULL_TREE;
}

/* For an lvalue tree LHS return true if it cannot be rewritten into SSA form.
   Otherwise return true.  */

static bool 
non_rewritable_lvalue_p (tree lhs)
{
  /* A plain decl is always rewritable.  */
  if (DECL_P (lhs))
    return false;

  /* A decl that is wrapped inside a MEM-REF that covers
     it full is also rewritable.
     ???  The following could be relaxed allowing component
     references that do not change the access size.  */
  if (TREE_CODE (lhs) == MEM_REF
      && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
      && integer_zerop (TREE_OPERAND (lhs, 1)))
    {
      tree decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
      if (DECL_P (decl)
	  && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs))
	  && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs)))
	return false;
    }

  return true;
}

/* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and
   mark the variable VAR for conversion into SSA.  Return true when updating
   stmts is required.  */

static void
maybe_optimize_var (tree var, bitmap addresses_taken, bitmap not_reg_needs,
		    bitmap suitable_for_renaming)
{
  /* Global Variables, result decls cannot be changed.  */
  if (is_global_var (var)
      || TREE_CODE (var) == RESULT_DECL
      || bitmap_bit_p (addresses_taken, DECL_UID (var)))
    return;

  if (TREE_ADDRESSABLE (var)
      /* Do not change TREE_ADDRESSABLE if we need to preserve var as
	 a non-register.  Otherwise we are confused and forget to
	 add virtual operands for it.  */
      && (!is_gimple_reg_type (TREE_TYPE (var))
	  || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE
	  || TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
	  || !bitmap_bit_p (not_reg_needs, DECL_UID (var))))
    {
      TREE_ADDRESSABLE (var) = 0;
      if (is_gimple_reg (var))
	bitmap_set_bit (suitable_for_renaming, DECL_UID (var));
      if (dump_file)
	{
	  fprintf (dump_file, "No longer having address taken: ");
	  print_generic_expr (dump_file, var, 0);
	  fprintf (dump_file, "\n");
	}
    }

  if (!DECL_GIMPLE_REG_P (var)
      && !bitmap_bit_p (not_reg_needs, DECL_UID (var))
      && (TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
	  || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE)
      && !TREE_THIS_VOLATILE (var)
      && (TREE_CODE (var) != VAR_DECL || !DECL_HARD_REGISTER (var)))
    {
      DECL_GIMPLE_REG_P (var) = 1;
      bitmap_set_bit (suitable_for_renaming, DECL_UID (var));
      if (dump_file)
	{
	  fprintf (dump_file, "Now a gimple register: ");
	  print_generic_expr (dump_file, var, 0);
	  fprintf (dump_file, "\n");
	}
    }
}

/* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables.  */

void
execute_update_addresses_taken (void)
{
  gimple_stmt_iterator gsi;
  basic_block bb;
  bitmap addresses_taken = BITMAP_ALLOC (NULL);
  bitmap not_reg_needs = BITMAP_ALLOC (NULL);
  bitmap suitable_for_renaming = BITMAP_ALLOC (NULL);
  tree var;
  unsigned i;

  timevar_push (TV_ADDRESS_TAKEN);

  /* Collect into ADDRESSES_TAKEN all variables whose address is taken within
     the function body.  */
  FOR_EACH_BB_FN (bb, cfun)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  gimple stmt = gsi_stmt (gsi);
	  enum gimple_code code = gimple_code (stmt);
	  tree decl;

	  /* Note all addresses taken by the stmt.  */
	  gimple_ior_addresses_taken (addresses_taken, stmt);

	  /* If we have a call or an assignment, see if the lhs contains
	     a local decl that requires not to be a gimple register.  */
	  if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
	    {
              tree lhs = gimple_get_lhs (stmt);
              if (lhs
		  && TREE_CODE (lhs) != SSA_NAME
		  && non_rewritable_lvalue_p (lhs))
		{
		  decl = get_base_address (lhs);
		  if (DECL_P (decl))
		    bitmap_set_bit (not_reg_needs, DECL_UID (decl));
                }
	    }

	  if (gimple_assign_single_p (stmt))
	    {
	      tree rhs = gimple_assign_rhs1 (stmt);
	      if ((decl = non_rewritable_mem_ref_base (rhs)))
		bitmap_set_bit (not_reg_needs, DECL_UID (decl));
	    }

	  else if (code == GIMPLE_CALL)
	    {
	      for (i = 0; i < gimple_call_num_args (stmt); ++i)
		{
		  tree arg = gimple_call_arg (stmt, i);
		  if ((decl = non_rewritable_mem_ref_base (arg)))
		    bitmap_set_bit (not_reg_needs, DECL_UID (decl));
		}
	    }

	  else if (code == GIMPLE_ASM)
	    {
	      for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
		{
		  tree link = gimple_asm_output_op (stmt, i);
		  tree lhs = TREE_VALUE (link);
		  if (TREE_CODE (lhs) != SSA_NAME)
		    {
		      decl = get_base_address (lhs);
		      if (DECL_P (decl)
			  && (non_rewritable_lvalue_p (lhs)
			      /* We cannot move required conversions from
				 the lhs to the rhs in asm statements, so
				 require we do not need any.  */
			      || !useless_type_conversion_p
			            (TREE_TYPE (lhs), TREE_TYPE (decl))))
			bitmap_set_bit (not_reg_needs, DECL_UID (decl));
		    }
		}
	      for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
		{
		  tree link = gimple_asm_input_op (stmt, i);
		  if ((decl = non_rewritable_mem_ref_base (TREE_VALUE (link))))
		    bitmap_set_bit (not_reg_needs, DECL_UID (decl));
		}
	    }
	}

      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  size_t i;
	  gimple phi = gsi_stmt (gsi);

	  for (i = 0; i < gimple_phi_num_args (phi); i++)
	    {
	      tree op = PHI_ARG_DEF (phi, i), var;
	      if (TREE_CODE (op) == ADDR_EXPR
		  && (var = get_base_address (TREE_OPERAND (op, 0))) != NULL
		  && DECL_P (var))
		bitmap_set_bit (addresses_taken, DECL_UID (var));
	    }
	}
    }

  /* We cannot iterate over all referenced vars because that can contain
     unused vars from BLOCK trees, which causes code generation differences
     for -g vs. -g0.  */
  for (var = DECL_ARGUMENTS (cfun->decl); var; var = DECL_CHAIN (var))
    maybe_optimize_var (var, addresses_taken, not_reg_needs,
			suitable_for_renaming);

  FOR_EACH_VEC_SAFE_ELT (cfun->local_decls, i, var)
    maybe_optimize_var (var, addresses_taken, not_reg_needs,
			suitable_for_renaming);

  /* Operand caches need to be recomputed for operands referencing the updated
     variables and operands need to be rewritten to expose bare symbols.  */
  if (!bitmap_empty_p (suitable_for_renaming))
    {
      FOR_EACH_BB_FN (bb, cfun)
	for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
	  {
	    gimple stmt = gsi_stmt (gsi);

	    /* Re-write TARGET_MEM_REFs of symbols we want to
	       rewrite into SSA form.  */
	    if (gimple_assign_single_p (stmt))
	      {
		tree lhs = gimple_assign_lhs (stmt);
		tree rhs, *rhsp = gimple_assign_rhs1_ptr (stmt);
		tree sym;

		/* We shouldn't have any fancy wrapping of
		   component-refs on the LHS, but look through
		   VIEW_CONVERT_EXPRs as that is easy.  */
		while (TREE_CODE (lhs) == VIEW_CONVERT_EXPR)
		  lhs = TREE_OPERAND (lhs, 0);
		if (TREE_CODE (lhs) == MEM_REF
		    && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
		    && integer_zerop (TREE_OPERAND (lhs, 1))
		    && (sym = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0))
		    && DECL_P (sym)
		    && !TREE_ADDRESSABLE (sym)
		    && bitmap_bit_p (suitable_for_renaming, DECL_UID (sym)))
		  lhs = sym;
		else
		  lhs = gimple_assign_lhs (stmt);

		/* Rewrite the RHS and make sure the resulting assignment
		   is validly typed.  */
		maybe_rewrite_mem_ref_base (rhsp, suitable_for_renaming);
		rhs = gimple_assign_rhs1 (stmt);
		if (gimple_assign_lhs (stmt) != lhs
		    && !useless_type_conversion_p (TREE_TYPE (lhs),
						   TREE_TYPE (rhs)))
		  rhs = fold_build1 (VIEW_CONVERT_EXPR,
				     TREE_TYPE (lhs), rhs);

		if (gimple_assign_lhs (stmt) != lhs)
		  gimple_assign_set_lhs (stmt, lhs);

		/* For var ={v} {CLOBBER}; where var lost
		   TREE_ADDRESSABLE just remove the stmt.  */
		if (DECL_P (lhs)
		    && TREE_CLOBBER_P (rhs)
		    && bitmap_bit_p (suitable_for_renaming, DECL_UID (lhs)))
		  {
		    unlink_stmt_vdef (stmt);
      		    gsi_remove (&gsi, true);
		    release_defs (stmt);
		    continue;
		  }

		if (gimple_assign_rhs1 (stmt) != rhs)
		  {
		    gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
		    gimple_assign_set_rhs_from_tree (&gsi, rhs);
		  }
	      }

	    else if (gimple_code (stmt) == GIMPLE_CALL)
	      {
		unsigned i;
		for (i = 0; i < gimple_call_num_args (stmt); ++i)
		  {
		    tree *argp = gimple_call_arg_ptr (stmt, i);
		    maybe_rewrite_mem_ref_base (argp, suitable_for_renaming);
		  }
	      }

	    else if (gimple_code (stmt) == GIMPLE_ASM)
	      {
		unsigned i;
		for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
		  {
		    tree link = gimple_asm_output_op (stmt, i);
		    maybe_rewrite_mem_ref_base (&TREE_VALUE (link),
						suitable_for_renaming);
		  }
		for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
		  {
		    tree link = gimple_asm_input_op (stmt, i);
		    maybe_rewrite_mem_ref_base (&TREE_VALUE (link),
						suitable_for_renaming);
		  }
	      }

	    else if (gimple_debug_bind_p (stmt)
		     && gimple_debug_bind_has_value_p (stmt))
	      {
		tree *valuep = gimple_debug_bind_get_value_ptr (stmt);
		tree decl;
		maybe_rewrite_mem_ref_base (valuep, suitable_for_renaming);
		decl = non_rewritable_mem_ref_base (*valuep);
		if (decl
		    && bitmap_bit_p (suitable_for_renaming, DECL_UID (decl)))
		  gimple_debug_bind_reset_value (stmt);
	      }

	    if (gimple_references_memory_p (stmt)
		|| is_gimple_debug (stmt))
	      update_stmt (stmt);

	    gsi_next (&gsi);
	  }

      /* Update SSA form here, we are called as non-pass as well.  */
      if (number_of_loops (cfun) > 1
	  && loops_state_satisfies_p (LOOP_CLOSED_SSA))
	rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
      else
	update_ssa (TODO_update_ssa);
    }

  BITMAP_FREE (not_reg_needs);
  BITMAP_FREE (addresses_taken);
  BITMAP_FREE (suitable_for_renaming);
  timevar_pop (TV_ADDRESS_TAKEN);
}

namespace {

const pass_data pass_data_update_address_taken =
{
  GIMPLE_PASS, /* type */
  "addressables", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  false, /* has_gate */
  false, /* has_execute */
  TV_ADDRESS_TAKEN, /* tv_id */
  PROP_ssa, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  TODO_update_address_taken, /* todo_flags_finish */
};

class pass_update_address_taken : public gimple_opt_pass
{
public:
  pass_update_address_taken (gcc::context *ctxt)
    : gimple_opt_pass (pass_data_update_address_taken, ctxt)
  {}

  /* opt_pass methods: */

}; // class pass_update_address_taken

} // anon namespace

gimple_opt_pass *
make_pass_update_address_taken (gcc::context *ctxt)
{
  return new pass_update_address_taken (ctxt);
}