aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.4.3/gcc/reginfo.c
blob: e579c281aa3a65c592e7f389b6efd80a8b54443c (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
/* Compute different info about registers.
   Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996
   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   2009  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/>.  */


/* This file contains regscan pass of the compiler and passes for
   dealing with info about modes of pseudo-registers inside
   subregisters.  It also defines some tables of information about the
   hardware registers, function init_reg_sets to initialize the
   tables, and other auxiliary functions to deal with info about
   registers and their classes.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "hard-reg-set.h"
#include "rtl.h"
#include "expr.h"
#include "tm_p.h"
#include "flags.h"
#include "basic-block.h"
#include "regs.h"
#include "addresses.h"
#include "function.h"
#include "insn-config.h"
#include "recog.h"
#include "reload.h"
#include "real.h"
#include "toplev.h"
#include "output.h"
#include "ggc.h"
#include "timevar.h"
#include "hashtab.h"
#include "target.h"
#include "tree-pass.h"
#include "df.h"
#include "ira.h"

/* Maximum register number used in this function, plus one.  */

int max_regno;


/* Register tables used by many passes.  */

/* Indexed by hard register number, contains 1 for registers
   that are fixed use (stack pointer, pc, frame pointer, etc.).
   These are the registers that cannot be used to allocate
   a pseudo reg for general use.  */
char fixed_regs[FIRST_PSEUDO_REGISTER];

/* Same info as a HARD_REG_SET.  */
HARD_REG_SET fixed_reg_set;

/* Data for initializing the above.  */
static const char initial_fixed_regs[] = FIXED_REGISTERS;

/* Indexed by hard register number, contains 1 for registers
   that are fixed use or are clobbered by function calls.
   These are the registers that cannot be used to allocate
   a pseudo reg whose life crosses calls unless we are able
   to save/restore them across the calls.  */
char call_used_regs[FIRST_PSEUDO_REGISTER];

/* Same info as a HARD_REG_SET.  */
HARD_REG_SET call_used_reg_set;

/* Data for initializing the above.  */
static const char initial_call_used_regs[] = CALL_USED_REGISTERS;

/* This is much like call_used_regs, except it doesn't have to
   be a superset of FIXED_REGISTERS. This vector indicates
   what is really call clobbered, and is used when defining
   regs_invalidated_by_call.  */
#ifdef CALL_REALLY_USED_REGISTERS
char call_really_used_regs[] = CALL_REALLY_USED_REGISTERS;
#endif

#ifdef CALL_REALLY_USED_REGISTERS
#define CALL_REALLY_USED_REGNO_P(X)  call_really_used_regs[X]
#else
#define CALL_REALLY_USED_REGNO_P(X)  call_used_regs[X]
#endif


/* Indexed by hard register number, contains 1 for registers that are
   fixed use or call used registers that cannot hold quantities across
   calls even if we are willing to save and restore them.  call fixed
   registers are a subset of call used registers.  */
char call_fixed_regs[FIRST_PSEUDO_REGISTER];

/* The same info as a HARD_REG_SET.  */
HARD_REG_SET call_fixed_reg_set;

/* Indexed by hard register number, contains 1 for registers
   that are being used for global register decls.
   These must be exempt from ordinary flow analysis
   and are also considered fixed.  */
char global_regs[FIRST_PSEUDO_REGISTER];

/* Contains 1 for registers that are set or clobbered by calls.  */
/* ??? Ideally, this would be just call_used_regs plus global_regs, but
   for someone's bright idea to have call_used_regs strictly include
   fixed_regs.  Which leaves us guessing as to the set of fixed_regs
   that are actually preserved.  We know for sure that those associated
   with the local stack frame are safe, but scant others.  */
HARD_REG_SET regs_invalidated_by_call;

/* Same information as REGS_INVALIDATED_BY_CALL but in regset form to be used
   in dataflow more conveniently.  */
regset regs_invalidated_by_call_regset;

/* The bitmap_obstack is used to hold some static variables that
   should not be reset after each function is compiled.  */
static bitmap_obstack persistent_obstack;

/* Table of register numbers in the order in which to try to use them.  */
#ifdef REG_ALLOC_ORDER
int reg_alloc_order[FIRST_PSEUDO_REGISTER] = REG_ALLOC_ORDER;

/* The inverse of reg_alloc_order.  */
int inv_reg_alloc_order[FIRST_PSEUDO_REGISTER];
#endif

/* For each reg class, a HARD_REG_SET saying which registers are in it.  */
HARD_REG_SET reg_class_contents[N_REG_CLASSES];

/* The same information, but as an array of unsigned ints.  We copy from
   these unsigned ints to the table above.  We do this so the tm.h files
   do not have to be aware of the wordsize for machines with <= 64 regs.
   Note that we hard-code 32 here, not HOST_BITS_PER_INT.  */
#define N_REG_INTS  \
  ((FIRST_PSEUDO_REGISTER + (32 - 1)) / 32)

static const unsigned int_reg_class_contents[N_REG_CLASSES][N_REG_INTS]
  = REG_CLASS_CONTENTS;

/* For each reg class, number of regs it contains.  */
unsigned int reg_class_size[N_REG_CLASSES];

/* For each reg class, table listing all the classes contained in it.  */
enum reg_class reg_class_subclasses[N_REG_CLASSES][N_REG_CLASSES];

/* For each pair of reg classes,
   a largest reg class contained in their union.  */
enum reg_class reg_class_subunion[N_REG_CLASSES][N_REG_CLASSES];

/* For each pair of reg classes,
   the smallest reg class containing their union.  */
enum reg_class reg_class_superunion[N_REG_CLASSES][N_REG_CLASSES];

/* Array containing all of the register names.  */
const char * reg_names[] = REGISTER_NAMES;

/* Array containing all of the register class names.  */
const char * reg_class_names[] = REG_CLASS_NAMES;

/* For each hard register, the widest mode object that it can contain.
   This will be a MODE_INT mode if the register can hold integers.  Otherwise
   it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
   register.  */
enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];

/* 1 if there is a register of given mode.  */
bool have_regs_of_mode [MAX_MACHINE_MODE];

/* 1 if class does contain register of given mode.  */
char contains_reg_of_mode [N_REG_CLASSES] [MAX_MACHINE_MODE];

/* Maximum cost of moving from a register in one class to a register in
   another class.  Based on REGISTER_MOVE_COST.  */
move_table *move_cost[MAX_MACHINE_MODE];

/* Similar, but here we don't have to move if the first index is a subset
   of the second so in that case the cost is zero.  */
move_table *may_move_in_cost[MAX_MACHINE_MODE];

/* Similar, but here we don't have to move if the first index is a superset
   of the second so in that case the cost is zero.  */
move_table *may_move_out_cost[MAX_MACHINE_MODE];

/* Keep track of the last mode we initialized move costs for.  */
static int last_mode_for_init_move_cost;

/* Sample MEM values for use by memory_move_secondary_cost.  */
static GTY(()) rtx top_of_stack[MAX_MACHINE_MODE];

/* No more global register variables may be declared; true once
   reginfo has been initialized.  */
static int no_global_reg_vars = 0;

/* Specify number of hard registers given machine mode occupy.  */
unsigned char hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];

/* Given a register bitmap, turn on the bits in a HARD_REG_SET that
   correspond to the hard registers, if any, set in that map.  This
   could be done far more efficiently by having all sorts of special-cases
   with moving single words, but probably isn't worth the trouble.  */
void
reg_set_to_hard_reg_set (HARD_REG_SET *to, const_bitmap from)
{
  unsigned i;
  bitmap_iterator bi;

  EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
    {
      if (i >= FIRST_PSEUDO_REGISTER)
	return;
      SET_HARD_REG_BIT (*to, i);
    }
}

/* Function called only once to initialize the above data on reg usage.
   Once this is done, various switches may override.  */
void
init_reg_sets (void)
{
  int i, j;

  /* First copy the register information from the initial int form into
     the regsets.  */

  for (i = 0; i < N_REG_CLASSES; i++)
    {
      CLEAR_HARD_REG_SET (reg_class_contents[i]);

      /* Note that we hard-code 32 here, not HOST_BITS_PER_INT.  */
      for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
	if (int_reg_class_contents[i][j / 32]
	    & ((unsigned) 1 << (j % 32)))
	  SET_HARD_REG_BIT (reg_class_contents[i], j);
    }

  /* Sanity check: make sure the target macros FIXED_REGISTERS and
     CALL_USED_REGISTERS had the right number of initializers.  */
  gcc_assert (sizeof fixed_regs == sizeof initial_fixed_regs);
  gcc_assert (sizeof call_used_regs == sizeof initial_call_used_regs);

  memcpy (fixed_regs, initial_fixed_regs, sizeof fixed_regs);
  memcpy (call_used_regs, initial_call_used_regs, sizeof call_used_regs);
  memset (global_regs, 0, sizeof global_regs);
}

/* Initialize may_move_cost and friends for mode M.  */
void
init_move_cost (enum machine_mode m)
{
  static unsigned short last_move_cost[N_REG_CLASSES][N_REG_CLASSES];
  bool all_match = true;
  unsigned int i, j;

  gcc_assert (have_regs_of_mode[m]);
  for (i = 0; i < N_REG_CLASSES; i++)
    if (contains_reg_of_mode[i][m])
      for (j = 0; j < N_REG_CLASSES; j++)
	{
	  int cost;
	  if (!contains_reg_of_mode[j][m])
	    cost = 65535;
	  else
	    {
	      cost = REGISTER_MOVE_COST (m, i, j);
	      gcc_assert (cost < 65535);
	    }
	  all_match &= (last_move_cost[i][j] == cost);
	  last_move_cost[i][j] = cost;
	}
  if (all_match && last_mode_for_init_move_cost != -1)
    {
      move_cost[m] = move_cost[last_mode_for_init_move_cost];
      may_move_in_cost[m] = may_move_in_cost[last_mode_for_init_move_cost];
      may_move_out_cost[m] = may_move_out_cost[last_mode_for_init_move_cost];
      return;
    }
  last_mode_for_init_move_cost = m;
  move_cost[m] = (move_table *)xmalloc (sizeof (move_table)
					* N_REG_CLASSES);
  may_move_in_cost[m] = (move_table *)xmalloc (sizeof (move_table)
					       * N_REG_CLASSES);
  may_move_out_cost[m] = (move_table *)xmalloc (sizeof (move_table)
					        * N_REG_CLASSES);
  for (i = 0; i < N_REG_CLASSES; i++)
    if (contains_reg_of_mode[i][m])
      for (j = 0; j < N_REG_CLASSES; j++)
	{
	  int cost;
	  enum reg_class *p1, *p2;

	  if (last_move_cost[i][j] == 65535)
	    {
	      move_cost[m][i][j] = 65535;
	      may_move_in_cost[m][i][j] = 65535;
	      may_move_out_cost[m][i][j] = 65535;
	    }
	  else
	    {
	      cost = last_move_cost[i][j];

	      for (p2 = &reg_class_subclasses[j][0];
		   *p2 != LIM_REG_CLASSES; p2++)
		if (*p2 != i && contains_reg_of_mode[*p2][m])
		  cost = MAX (cost, move_cost[m][i][*p2]);

	      for (p1 = &reg_class_subclasses[i][0];
		   *p1 != LIM_REG_CLASSES; p1++)
		if (*p1 != j && contains_reg_of_mode[*p1][m])
		  cost = MAX (cost, move_cost[m][*p1][j]);

	      gcc_assert (cost <= 65535);
	      move_cost[m][i][j] = cost;

	      if (reg_class_subset_p (i, j))
		may_move_in_cost[m][i][j] = 0;
	      else
		may_move_in_cost[m][i][j] = cost;

	      if (reg_class_subset_p (j, i))
		may_move_out_cost[m][i][j] = 0;
	      else
		may_move_out_cost[m][i][j] = cost;
	    }
	}
    else
      for (j = 0; j < N_REG_CLASSES; j++)
	{
	  move_cost[m][i][j] = 65535;
	  may_move_in_cost[m][i][j] = 65535;
	  may_move_out_cost[m][i][j] = 65535;
	}
}

/* We need to save copies of some of the register information which
   can be munged by command-line switches so we can restore it during
   subsequent back-end reinitialization.  */
static char saved_fixed_regs[FIRST_PSEUDO_REGISTER];
static char saved_call_used_regs[FIRST_PSEUDO_REGISTER];
#ifdef CALL_REALLY_USED_REGISTERS
static char saved_call_really_used_regs[FIRST_PSEUDO_REGISTER];
#endif
static const char *saved_reg_names[FIRST_PSEUDO_REGISTER];

/* Save the register information.  */
void
save_register_info (void)
{
  /* Sanity check:  make sure the target macros FIXED_REGISTERS and
     CALL_USED_REGISTERS had the right number of initializers.  */
  gcc_assert (sizeof fixed_regs == sizeof saved_fixed_regs);
  gcc_assert (sizeof call_used_regs == sizeof saved_call_used_regs);
  memcpy (saved_fixed_regs, fixed_regs, sizeof fixed_regs);
  memcpy (saved_call_used_regs, call_used_regs, sizeof call_used_regs);

  /* Likewise for call_really_used_regs.  */
#ifdef CALL_REALLY_USED_REGISTERS
  gcc_assert (sizeof call_really_used_regs
	      == sizeof saved_call_really_used_regs);
  memcpy (saved_call_really_used_regs, call_really_used_regs,
	  sizeof call_really_used_regs);
#endif

  /* And similarly for reg_names.  */
  gcc_assert (sizeof reg_names == sizeof saved_reg_names);
  memcpy (saved_reg_names, reg_names, sizeof reg_names);
}

/* Restore the register information.  */
static void
restore_register_info (void)
{
  memcpy (fixed_regs, saved_fixed_regs, sizeof fixed_regs);
  memcpy (call_used_regs, saved_call_used_regs, sizeof call_used_regs);

#ifdef CALL_REALLY_USED_REGISTERS
  memcpy (call_really_used_regs, saved_call_really_used_regs,
	  sizeof call_really_used_regs);
#endif

  memcpy (reg_names, saved_reg_names, sizeof reg_names);
}

/* After switches have been processed, which perhaps alter
   `fixed_regs' and `call_used_regs', convert them to HARD_REG_SETs.  */
static void
init_reg_sets_1 (void)
{
  unsigned int i, j;
  unsigned int /* enum machine_mode */ m;

  restore_register_info ();

#ifdef REG_ALLOC_ORDER
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    inv_reg_alloc_order[reg_alloc_order[i]] = i;
#endif

  /* This macro allows the fixed or call-used registers
     and the register classes to depend on target flags.  */

#ifdef CONDITIONAL_REGISTER_USAGE
  CONDITIONAL_REGISTER_USAGE;
#endif

  /* Compute number of hard regs in each class.  */

  memset (reg_class_size, 0, sizeof reg_class_size);
  for (i = 0; i < N_REG_CLASSES; i++)
    for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
      if (TEST_HARD_REG_BIT (reg_class_contents[i], j))
	reg_class_size[i]++;

  /* Initialize the table of subunions.
     reg_class_subunion[I][J] gets the largest-numbered reg-class
     that is contained in the union of classes I and J.  */

  memset (reg_class_subunion, 0, sizeof reg_class_subunion);
  for (i = 0; i < N_REG_CLASSES; i++)
    {
      for (j = 0; j < N_REG_CLASSES; j++)
	{
	  HARD_REG_SET c;
	  int k;

	  COPY_HARD_REG_SET (c, reg_class_contents[i]);
	  IOR_HARD_REG_SET (c, reg_class_contents[j]);
	  for (k = 0; k < N_REG_CLASSES; k++)
	    if (hard_reg_set_subset_p (reg_class_contents[k], c)
		&& !hard_reg_set_subset_p (reg_class_contents[k],
					  reg_class_contents
					  [(int) reg_class_subunion[i][j]]))
	      reg_class_subunion[i][j] = (enum reg_class) k;
	}
    }

  /* Initialize the table of superunions.
     reg_class_superunion[I][J] gets the smallest-numbered reg-class
     containing the union of classes I and J.  */

  memset (reg_class_superunion, 0, sizeof reg_class_superunion);
  for (i = 0; i < N_REG_CLASSES; i++)
    {
      for (j = 0; j < N_REG_CLASSES; j++)
	{
	  HARD_REG_SET c;
	  int k;

	  COPY_HARD_REG_SET (c, reg_class_contents[i]);
	  IOR_HARD_REG_SET (c, reg_class_contents[j]);
	  for (k = 0; k < N_REG_CLASSES; k++)
	    if (hard_reg_set_subset_p (c, reg_class_contents[k]))
	      break;

	  reg_class_superunion[i][j] = (enum reg_class) k;
	}
    }

  /* Initialize the tables of subclasses and superclasses of each reg class.
     First clear the whole table, then add the elements as they are found.  */

  for (i = 0; i < N_REG_CLASSES; i++)
    {
      for (j = 0; j < N_REG_CLASSES; j++)
	reg_class_subclasses[i][j] = LIM_REG_CLASSES;
    }

  for (i = 0; i < N_REG_CLASSES; i++)
    {
      if (i == (int) NO_REGS)
	continue;

      for (j = i + 1; j < N_REG_CLASSES; j++)
	if (hard_reg_set_subset_p (reg_class_contents[i],
				  reg_class_contents[j]))
	  {
	    /* Reg class I is a subclass of J.
	       Add J to the table of superclasses of I.  */
	    enum reg_class *p;

	    /* Add I to the table of superclasses of J.  */
	    p = &reg_class_subclasses[j][0];
	    while (*p != LIM_REG_CLASSES) p++;
	    *p = (enum reg_class) i;
	  }
    }

  /* Initialize "constant" tables.  */

  CLEAR_HARD_REG_SET (fixed_reg_set);
  CLEAR_HARD_REG_SET (call_used_reg_set);
  CLEAR_HARD_REG_SET (call_fixed_reg_set);
  CLEAR_HARD_REG_SET (regs_invalidated_by_call);
  if (!regs_invalidated_by_call_regset)
    {
      bitmap_obstack_initialize (&persistent_obstack);
      regs_invalidated_by_call_regset = ALLOC_REG_SET (&persistent_obstack);
    }
  else
    CLEAR_REG_SET (regs_invalidated_by_call_regset);

  memcpy (call_fixed_regs, fixed_regs, sizeof call_fixed_regs);

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      /* call_used_regs must include fixed_regs.  */
      gcc_assert (!fixed_regs[i] || call_used_regs[i]);
#ifdef CALL_REALLY_USED_REGISTERS
      /* call_used_regs must include call_really_used_regs.  */
      gcc_assert (!call_really_used_regs[i] || call_used_regs[i]);
#endif

      if (fixed_regs[i])
	SET_HARD_REG_BIT (fixed_reg_set, i);

      if (call_used_regs[i])
	SET_HARD_REG_BIT (call_used_reg_set, i);
      if (call_fixed_regs[i])
	SET_HARD_REG_BIT (call_fixed_reg_set, i);

      /* There are a couple of fixed registers that we know are safe to
	 exclude from being clobbered by calls:

	 The frame pointer is always preserved across calls.  The arg pointer
	 is if it is fixed.  The stack pointer usually is, unless
	 RETURN_POPS_ARGS, in which case an explicit CLOBBER will be present.
	 If we are generating PIC code, the PIC offset table register is
	 preserved across calls, though the target can override that.  */

      if (i == STACK_POINTER_REGNUM)
	;
      else if (global_regs[i])
        {
	  SET_HARD_REG_BIT (regs_invalidated_by_call, i);
	  SET_REGNO_REG_SET (regs_invalidated_by_call_regset, i);
	}
      else if (i == FRAME_POINTER_REGNUM)
	;
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
      else if (i == HARD_FRAME_POINTER_REGNUM)
	;
#endif
#if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
      else if (i == ARG_POINTER_REGNUM && fixed_regs[i])
	;
#endif
#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
      else if (i == (unsigned) PIC_OFFSET_TABLE_REGNUM && fixed_regs[i])
	;
#endif
      else if (CALL_REALLY_USED_REGNO_P (i))
        {
	  SET_HARD_REG_BIT (regs_invalidated_by_call, i);
	  SET_REGNO_REG_SET (regs_invalidated_by_call_regset, i);
        }
    }

  /* Preserve global registers if called more than once.  */
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      if (global_regs[i])
	{
	  fixed_regs[i] = call_used_regs[i] = call_fixed_regs[i] = 1;
	  SET_HARD_REG_BIT (fixed_reg_set, i);
	  SET_HARD_REG_BIT (call_used_reg_set, i);
	  SET_HARD_REG_BIT (call_fixed_reg_set, i);
	}
    }

  memset (have_regs_of_mode, 0, sizeof (have_regs_of_mode));
  memset (contains_reg_of_mode, 0, sizeof (contains_reg_of_mode));
  for (m = 0; m < (unsigned int) MAX_MACHINE_MODE; m++)
    {
      HARD_REG_SET ok_regs;
      CLEAR_HARD_REG_SET (ok_regs);
      for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
	if (!fixed_regs [j] && HARD_REGNO_MODE_OK (j, m))
	  SET_HARD_REG_BIT (ok_regs, j);
      
      for (i = 0; i < N_REG_CLASSES; i++)
	if ((unsigned) CLASS_MAX_NREGS (i, m) <= reg_class_size[i]
	    && hard_reg_set_intersect_p (ok_regs, reg_class_contents[i]))
	  {
	     contains_reg_of_mode [i][m] = 1;
	     have_regs_of_mode [m] = 1;
	  }
     }

  /* Reset move_cost and friends, making sure we only free shared
     table entries once.  */
  for (i = 0; i < MAX_MACHINE_MODE; i++)
    if (move_cost[i])
      {
	for (j = 0; j < i && move_cost[i] != move_cost[j]; j++)
	  ;
	if (i == j)
	  {
	    free (move_cost[i]);
	    free (may_move_in_cost[i]);
	    free (may_move_out_cost[i]);
	  }
      }
  memset (move_cost, 0, sizeof move_cost);
  memset (may_move_in_cost, 0, sizeof may_move_in_cost);
  memset (may_move_out_cost, 0, sizeof may_move_out_cost);
  last_mode_for_init_move_cost = -1;
}

/* Compute the table of register modes.
   These values are used to record death information for individual registers
   (as opposed to a multi-register mode).
   This function might be invoked more than once, if the target has support
   for changing register usage conventions on a per-function basis.
*/
void
init_reg_modes_target (void)
{
  int i, j;

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    for (j = 0; j < MAX_MACHINE_MODE; j++)
      hard_regno_nregs[i][j] = HARD_REGNO_NREGS(i, (enum machine_mode)j);

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      reg_raw_mode[i] = choose_hard_reg_mode (i, 1, false);

      /* If we couldn't find a valid mode, just use the previous mode.
         ??? One situation in which we need to do this is on the mips where
	 HARD_REGNO_NREGS (fpreg, [SD]Fmode) returns 2.  Ideally we'd like
	 to use DF mode for the even registers and VOIDmode for the odd
	 (for the cpu models where the odd ones are inaccessible).  */
      if (reg_raw_mode[i] == VOIDmode)
	reg_raw_mode[i] = i == 0 ? word_mode : reg_raw_mode[i-1];
    }
}

/* Finish initializing the register sets and initialize the register modes.
   This function might be invoked more than once, if the target has support
   for changing register usage conventions on a per-function basis.
*/
void
init_regs (void)
{
  /* This finishes what was started by init_reg_sets, but couldn't be done
     until after register usage was specified.  */
  init_reg_sets_1 ();
}

/* The same as previous function plus initializing IRA.  */
void
reinit_regs (void)
{
  init_regs ();
  ira_init ();
}

/* Initialize some fake stack-frame MEM references for use in
   memory_move_secondary_cost.  */
void
init_fake_stack_mems (void)
{
  int i;
  
  for (i = 0; i < MAX_MACHINE_MODE; i++)
    top_of_stack[i] = gen_rtx_MEM (i, stack_pointer_rtx);
}


/* Compute extra cost of moving registers to/from memory due to reloads.
   Only needed if secondary reloads are required for memory moves.  */
int
memory_move_secondary_cost (enum machine_mode mode, enum reg_class rclass,
			    int in)
{
  enum reg_class altclass;
  int partial_cost = 0;
  /* We need a memory reference to feed to SECONDARY... macros.  */
  /* mem may be unused even if the SECONDARY_ macros are defined.  */
  rtx mem ATTRIBUTE_UNUSED = top_of_stack[(int) mode];

  altclass = secondary_reload_class (in ? 1 : 0, rclass, mode, mem);

  if (altclass == NO_REGS)
    return 0;

  if (in)
    partial_cost = REGISTER_MOVE_COST (mode, altclass, rclass);
  else
    partial_cost = REGISTER_MOVE_COST (mode, rclass, altclass);

  if (rclass == altclass)
    /* This isn't simply a copy-to-temporary situation.  Can't guess
       what it is, so MEMORY_MOVE_COST really ought not to be calling
       here in that case.

       I'm tempted to put in an assert here, but returning this will
       probably only give poor estimates, which is what we would've
       had before this code anyways.  */
    return partial_cost;

  /* Check if the secondary reload register will also need a
     secondary reload.  */
  return memory_move_secondary_cost (mode, altclass, in) + partial_cost;
}

/* Return a machine mode that is legitimate for hard reg REGNO and large
   enough to save nregs.  If we can't find one, return VOIDmode.
   If CALL_SAVED is true, only consider modes that are call saved.  */
enum machine_mode
choose_hard_reg_mode (unsigned int regno ATTRIBUTE_UNUSED,
		      unsigned int nregs, bool call_saved)
{
  unsigned int /* enum machine_mode */ m;
  enum machine_mode found_mode = VOIDmode, mode;

  /* We first look for the largest integer mode that can be validly
     held in REGNO.  If none, we look for the largest floating-point mode.
     If we still didn't find a valid mode, try CCmode.  */

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
       mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    if ((unsigned) hard_regno_nregs[regno][mode] == nregs
	&& HARD_REGNO_MODE_OK (regno, mode)
	&& (! call_saved || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
      found_mode = mode;

  if (found_mode != VOIDmode)
    return found_mode;

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
       mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    if ((unsigned) hard_regno_nregs[regno][mode] == nregs
	&& HARD_REGNO_MODE_OK (regno, mode)
	&& (! call_saved || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
      found_mode = mode;

  if (found_mode != VOIDmode)
    return found_mode;

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_FLOAT);
       mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    if ((unsigned) hard_regno_nregs[regno][mode] == nregs
	&& HARD_REGNO_MODE_OK (regno, mode)
	&& (! call_saved || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
      found_mode = mode;

  if (found_mode != VOIDmode)
    return found_mode;

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_INT);
       mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    if ((unsigned) hard_regno_nregs[regno][mode] == nregs
	&& HARD_REGNO_MODE_OK (regno, mode)
	&& (! call_saved || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
      found_mode = mode;

  if (found_mode != VOIDmode)
    return found_mode;

  /* Iterate over all of the CCmodes.  */
  for (m = (unsigned int) CCmode; m < (unsigned int) NUM_MACHINE_MODES; ++m)
    {
      mode = (enum machine_mode) m;
      if ((unsigned) hard_regno_nregs[regno][mode] == nregs
	  && HARD_REGNO_MODE_OK (regno, mode)
	  && (! call_saved || ! HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
	return mode;
    }

  /* We can't find a mode valid for this register.  */
  return VOIDmode;
}

/* Specify the usage characteristics of the register named NAME.
   It should be a fixed register if FIXED and a
   call-used register if CALL_USED.  */
void
fix_register (const char *name, int fixed, int call_used)
{
  int i;

  /* Decode the name and update the primary form of
     the register info.  */

  if ((i = decode_reg_name (name)) >= 0)
    {
      if ((i == STACK_POINTER_REGNUM
#ifdef HARD_FRAME_POINTER_REGNUM
	   || i == HARD_FRAME_POINTER_REGNUM
#else
	   || i == FRAME_POINTER_REGNUM
#endif
	   )
	  && (fixed == 0 || call_used == 0))
	{
	  static const char * const what_option[2][2] = {
	    { "call-saved", "call-used" },
	    { "no-such-option", "fixed" }};

	  error ("can't use '%s' as a %s register", name,
		 what_option[fixed][call_used]);
	}
      else
	{
	  fixed_regs[i] = fixed;
	  call_used_regs[i] = call_used;
#ifdef CALL_REALLY_USED_REGISTERS
	  if (fixed == 0)
	    call_really_used_regs[i] = call_used;
#endif
	}
    }
  else
    {
      warning (0, "unknown register name: %s", name);
    }
}

/* Mark register number I as global.  */
void
globalize_reg (int i)
{
  if (fixed_regs[i] == 0 && no_global_reg_vars)
    error ("global register variable follows a function definition");

  if (global_regs[i])
    {
      warning (0, "register used for two global register variables");
      return;
    }

  if (call_used_regs[i] && ! fixed_regs[i])
    warning (0, "call-clobbered register used for global register variable");

  global_regs[i] = 1;

  /* If we're globalizing the frame pointer, we need to set the
     appropriate regs_invalidated_by_call bit, even if it's already
     set in fixed_regs.  */
  if (i != STACK_POINTER_REGNUM)
    {
      SET_HARD_REG_BIT (regs_invalidated_by_call, i);
      SET_REGNO_REG_SET (regs_invalidated_by_call_regset, i);
    }

  /* If already fixed, nothing else to do.  */
  if (fixed_regs[i])
    return;

  fixed_regs[i] = call_used_regs[i] = call_fixed_regs[i] = 1;
#ifdef CALL_REALLY_USED_REGISTERS
  call_really_used_regs[i] = 1;
#endif

  SET_HARD_REG_BIT (fixed_reg_set, i);
  SET_HARD_REG_BIT (call_used_reg_set, i);
  SET_HARD_REG_BIT (call_fixed_reg_set, i);

  reinit_regs ();
}


/* Structure used to record preferences of given pseudo.  */
struct reg_pref
{
  /* (enum reg_class) prefclass is the preferred class.  May be
     NO_REGS if no class is better than memory.  */
  char prefclass;

  /* altclass is a register class that we should use for allocating
     pseudo if no register in the preferred class is available.
     If no register in this class is available, memory is preferred.

     It might appear to be more general to have a bitmask of classes here,
     but since it is recommended that there be a class corresponding to the
     union of most major pair of classes, that generality is not required.  */
  char altclass;
};

/* Record preferences of each pseudo.  This is available after RA is
   run.  */
static struct reg_pref *reg_pref;

/* Return the reg_class in which pseudo reg number REGNO is best allocated.
   This function is sometimes called before the info has been computed.
   When that happens, just return GENERAL_REGS, which is innocuous.  */
enum reg_class
reg_preferred_class (int regno)
{
  if (reg_pref == 0)
    return GENERAL_REGS;

  return (enum reg_class) reg_pref[regno].prefclass;
}

enum reg_class
reg_alternate_class (int regno)
{
  if (reg_pref == 0)
    return ALL_REGS;

  return (enum reg_class) reg_pref[regno].altclass;
}

/* Initialize some global data for this pass.  */
static unsigned int 
reginfo_init (void)
{
  if (df)
    df_compute_regs_ever_live (true);

  /* This prevents dump_flow_info from losing if called
     before reginfo is run.  */
  reg_pref = NULL;

  /* No more global register variables may be declared.  */
  no_global_reg_vars = 1;
  return 1;
}

struct rtl_opt_pass pass_reginfo_init =
{
 {
  RTL_PASS,
  "reginfo",                            /* name */
  NULL,                                 /* gate */
  reginfo_init,                         /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0                                     /* todo_flags_finish */
 }
};



/* Allocate space for reg info.  */
void
allocate_reg_info (void)
{
  int size = max_reg_num ();

  gcc_assert (! reg_pref && ! reg_renumber);
  reg_renumber = XNEWVEC (short, size);
  reg_pref = XCNEWVEC (struct reg_pref, size);
  memset (reg_renumber, -1, size * sizeof (short));
}


/* Resize reg info. The new elements will be uninitialized.  */
void
resize_reg_info (void)
{
  int size = max_reg_num ();

  gcc_assert (reg_pref && reg_renumber);
  reg_renumber = XRESIZEVEC (short, reg_renumber, size);
  reg_pref = XRESIZEVEC (struct reg_pref, reg_pref, size);
}


/* Free up the space allocated by allocate_reg_info.  */
void
free_reg_info (void)
{
  if (reg_pref)
    {
      free (reg_pref);
      reg_pref = NULL;
    }

  if (reg_renumber)
    {
      free (reg_renumber);
      reg_renumber = NULL;
    }
}




/* Set up preferred and alternate classes for REGNO as PREFCLASS and
   ALTCLASS.  */
void
setup_reg_classes (int regno,
		   enum reg_class prefclass, enum reg_class altclass)
{
  if (reg_pref == NULL)
    return;
  reg_pref[regno].prefclass = prefclass;
  reg_pref[regno].altclass = altclass;
}


/* This is the `regscan' pass of the compiler, run just before cse and
   again just before loop.  It finds the first and last use of each
   pseudo-register.  */

static void reg_scan_mark_refs (rtx, rtx);

void
reg_scan (rtx f, unsigned int nregs ATTRIBUTE_UNUSED)
{
  rtx insn;

  timevar_push (TV_REG_SCAN);

  for (insn = f; insn; insn = NEXT_INSN (insn))
    if (INSN_P (insn))
      {
	reg_scan_mark_refs (PATTERN (insn), insn);
	if (REG_NOTES (insn))
	  reg_scan_mark_refs (REG_NOTES (insn), insn);
      }

  timevar_pop (TV_REG_SCAN);
}


/* X is the expression to scan.  INSN is the insn it appears in.
   NOTE_FLAG is nonzero if X is from INSN's notes rather than its body.
   We should only record information for REGs with numbers
   greater than or equal to MIN_REGNO.  */
static void
reg_scan_mark_refs (rtx x, rtx insn)
{
  enum rtx_code code;
  rtx dest;
  rtx note;

  if (!x)
    return;
  code = GET_CODE (x);
  switch (code)
    {
    case CONST:
    case CONST_INT:
    case CONST_DOUBLE:
    case CONST_FIXED:
    case CONST_VECTOR:
    case CC0:
    case PC:
    case SYMBOL_REF:
    case LABEL_REF:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
    case REG:
      return;

    case EXPR_LIST:
      if (XEXP (x, 0))
	reg_scan_mark_refs (XEXP (x, 0), insn);
      if (XEXP (x, 1))
	reg_scan_mark_refs (XEXP (x, 1), insn);
      break;

    case INSN_LIST:
      if (XEXP (x, 1))
	reg_scan_mark_refs (XEXP (x, 1), insn);
      break;

    case CLOBBER:
      if (MEM_P (XEXP (x, 0)))
	reg_scan_mark_refs (XEXP (XEXP (x, 0), 0), insn);
      break;

    case SET:
      /* Count a set of the destination if it is a register.  */
      for (dest = SET_DEST (x);
	   GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
	   || GET_CODE (dest) == ZERO_EXTEND;
	   dest = XEXP (dest, 0))
	;

      /* If this is setting a pseudo from another pseudo or the sum of a
	 pseudo and a constant integer and the other pseudo is known to be
	 a pointer, set the destination to be a pointer as well.

	 Likewise if it is setting the destination from an address or from a
	 value equivalent to an address or to the sum of an address and
	 something else.

	 But don't do any of this if the pseudo corresponds to a user
	 variable since it should have already been set as a pointer based
	 on the type.  */

      if (REG_P (SET_DEST (x))
	  && REGNO (SET_DEST (x)) >= FIRST_PSEUDO_REGISTER
	  /* If the destination pseudo is set more than once, then other
	     sets might not be to a pointer value (consider access to a
	     union in two threads of control in the presence of global
	     optimizations).  So only set REG_POINTER on the destination
	     pseudo if this is the only set of that pseudo.  */
	  && DF_REG_DEF_COUNT (REGNO (SET_DEST (x))) == 1
	  && ! REG_USERVAR_P (SET_DEST (x))
	  && ! REG_POINTER (SET_DEST (x))
	  && ((REG_P (SET_SRC (x))
	       && REG_POINTER (SET_SRC (x)))
	      || ((GET_CODE (SET_SRC (x)) == PLUS
		   || GET_CODE (SET_SRC (x)) == LO_SUM)
		  && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
		  && REG_P (XEXP (SET_SRC (x), 0))
		  && REG_POINTER (XEXP (SET_SRC (x), 0)))
	      || GET_CODE (SET_SRC (x)) == CONST
	      || GET_CODE (SET_SRC (x)) == SYMBOL_REF
	      || GET_CODE (SET_SRC (x)) == LABEL_REF
	      || (GET_CODE (SET_SRC (x)) == HIGH
		  && (GET_CODE (XEXP (SET_SRC (x), 0)) == CONST
		      || GET_CODE (XEXP (SET_SRC (x), 0)) == SYMBOL_REF
		      || GET_CODE (XEXP (SET_SRC (x), 0)) == LABEL_REF))
	      || ((GET_CODE (SET_SRC (x)) == PLUS
		   || GET_CODE (SET_SRC (x)) == LO_SUM)
		  && (GET_CODE (XEXP (SET_SRC (x), 1)) == CONST
		      || GET_CODE (XEXP (SET_SRC (x), 1)) == SYMBOL_REF
		      || GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF))
	      || ((note = find_reg_note (insn, REG_EQUAL, 0)) != 0
		  && (GET_CODE (XEXP (note, 0)) == CONST
		      || GET_CODE (XEXP (note, 0)) == SYMBOL_REF
		      || GET_CODE (XEXP (note, 0)) == LABEL_REF))))
	REG_POINTER (SET_DEST (x)) = 1;

      /* If this is setting a register from a register or from a simple
	 conversion of a register, propagate REG_EXPR.  */
      if (REG_P (dest) && !REG_ATTRS (dest))
	{
	  rtx src = SET_SRC (x);

	  while (GET_CODE (src) == SIGN_EXTEND
		 || GET_CODE (src) == ZERO_EXTEND
		 || GET_CODE (src) == TRUNCATE
		 || (GET_CODE (src) == SUBREG && subreg_lowpart_p (src)))
	    src = XEXP (src, 0);

	  set_reg_attrs_from_value (dest, src);
	}

      /* ... fall through ...  */

    default:
      {
	const char *fmt = GET_RTX_FORMAT (code);
	int i;
	for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
	  {
	    if (fmt[i] == 'e')
	      reg_scan_mark_refs (XEXP (x, i), insn);
	    else if (fmt[i] == 'E' && XVEC (x, i) != 0)
	      {
		int j;
		for (j = XVECLEN (x, i) - 1; j >= 0; j--)
		  reg_scan_mark_refs (XVECEXP (x, i, j), insn);
	      }
	  }
      }
    }
}


/* Return nonzero if C1 is a subset of C2, i.e., if every register in C1
   is also in C2.  */
int
reg_class_subset_p (enum reg_class c1, enum reg_class c2)
{
  return (c1 == c2
	  || c2 == ALL_REGS
	  || hard_reg_set_subset_p (reg_class_contents[(int) c1],
				   reg_class_contents[(int) c2]));
}

/* Return nonzero if there is a register that is in both C1 and C2.  */
int
reg_classes_intersect_p (enum reg_class c1, enum reg_class c2)
{
  return (c1 == c2
	  || c1 == ALL_REGS
	  || c2 == ALL_REGS
	  || hard_reg_set_intersect_p (reg_class_contents[(int) c1],
				      reg_class_contents[(int) c2]));
}



/* Passes for keeping and updating info about modes of registers
   inside subregisters.  */

#ifdef CANNOT_CHANGE_MODE_CLASS

struct subregs_of_mode_node
{
  unsigned int block;
  unsigned char modes[MAX_MACHINE_MODE];
};

static htab_t subregs_of_mode;

static hashval_t
som_hash (const void *x)
{
  const struct subregs_of_mode_node *const a =
    (const struct subregs_of_mode_node *) x;
  return a->block;
}

static int
som_eq (const void *x, const void *y)
{
  const struct subregs_of_mode_node *const a =
    (const struct subregs_of_mode_node *) x;
  const struct subregs_of_mode_node *const b =
    (const struct subregs_of_mode_node *) y;
  return a->block == b->block;
}

static void
record_subregs_of_mode (rtx subreg)
{
  struct subregs_of_mode_node dummy, *node;
  enum machine_mode mode;
  unsigned int regno;
  void **slot;

  if (!REG_P (SUBREG_REG (subreg)))
    return;

  regno = REGNO (SUBREG_REG (subreg));
  mode = GET_MODE (subreg);

  if (regno < FIRST_PSEUDO_REGISTER)
    return;

  dummy.block = regno & -8;
  slot = htab_find_slot_with_hash (subregs_of_mode, &dummy,
				   dummy.block, INSERT);
  node = (struct subregs_of_mode_node *) *slot;
  if (node == NULL)
    {
      node = XCNEW (struct subregs_of_mode_node);
      node->block = regno & -8;
      *slot = node;
    }

  node->modes[mode] |= 1 << (regno & 7);
}

/* Call record_subregs_of_mode for all the subregs in X.  */
static void 
find_subregs_of_mode (rtx x)
{
  enum rtx_code code = GET_CODE (x);
  const char * const fmt = GET_RTX_FORMAT (code);
  int i;

  if (code == SUBREG)
    record_subregs_of_mode (x);
    
  /* Time for some deep diving.  */
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	find_subregs_of_mode (XEXP (x, i));
      else if (fmt[i] == 'E')
	{
	  int j;
	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
	    find_subregs_of_mode (XVECEXP (x, i, j));
	}
    }
}

static unsigned int
init_subregs_of_mode (void)
{
  basic_block bb;
  rtx insn;

  if (subregs_of_mode)
    htab_empty (subregs_of_mode);
  else
    subregs_of_mode = htab_create (100, som_hash, som_eq, free);

  FOR_EACH_BB (bb)
    FOR_BB_INSNS (bb, insn)
    if (INSN_P (insn))
      find_subregs_of_mode (PATTERN (insn));

  return 0;
}

/* Set bits in *USED which correspond to registers which can't change
   their mode from FROM to any mode in which REGNO was
   encountered.  */
void
cannot_change_mode_set_regs (HARD_REG_SET *used, enum machine_mode from,
			     unsigned int regno)
{
  struct subregs_of_mode_node dummy, *node;
  enum machine_mode to;
  unsigned char mask;
  unsigned int i;

  gcc_assert (subregs_of_mode);
  dummy.block = regno & -8;
  node = (struct subregs_of_mode_node *)
    htab_find_with_hash (subregs_of_mode, &dummy, dummy.block);
  if (node == NULL)
    return;

  mask = 1 << (regno & 7);
  for (to = VOIDmode; to < NUM_MACHINE_MODES; to++)
    if (node->modes[to] & mask)
      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if (!TEST_HARD_REG_BIT (*used, i)
	    && REG_CANNOT_CHANGE_MODE_P (i, from, to))
	  SET_HARD_REG_BIT (*used, i);
}

/* Return 1 if REGNO has had an invalid mode change in CLASS from FROM
   mode.  */
bool
invalid_mode_change_p (unsigned int regno,
		       enum reg_class rclass ATTRIBUTE_UNUSED,
		       enum machine_mode from)
{
  struct subregs_of_mode_node dummy, *node;
  enum machine_mode to;
  unsigned char mask;

  gcc_assert (subregs_of_mode);
  dummy.block = regno & -8;
  node = (struct subregs_of_mode_node *)
    htab_find_with_hash (subregs_of_mode, &dummy, dummy.block);
  if (node == NULL)
    return false;

  mask = 1 << (regno & 7);
  for (to = VOIDmode; to < NUM_MACHINE_MODES; to++)
    if (node->modes[to] & mask)
      if (CANNOT_CHANGE_MODE_CLASS (from, to, rclass))
	return true;

  return false;
}

static unsigned int
finish_subregs_of_mode (void)
{
  htab_delete (subregs_of_mode);
  subregs_of_mode = 0;
  return 0;
}
#else
static unsigned int
init_subregs_of_mode (void)
{
  return 0;
}
static unsigned int
finish_subregs_of_mode (void)
{
  return 0;
}

#endif /* CANNOT_CHANGE_MODE_CLASS */

static bool
gate_subregs_of_mode_init (void)
{
#ifdef CANNOT_CHANGE_MODE_CLASS
  return true;
#else
  return false;
#endif
}

struct rtl_opt_pass pass_subregs_of_mode_init =
{
 {
  RTL_PASS,
  "subregs_of_mode_init",               /* name */
  gate_subregs_of_mode_init,            /* gate */
  init_subregs_of_mode,                 /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0                                     /* todo_flags_finish */
 }
};

struct rtl_opt_pass pass_subregs_of_mode_finish =
{
 {
  RTL_PASS,
  "subregs_of_mode_finish",               /* name */
  gate_subregs_of_mode_init,            /* gate */
  finish_subregs_of_mode,               /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0                                     /* todo_flags_finish */
 }
};


#include "gt-reginfo.h"