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
|
/* Common subexpression elimination library for GNU compiler.
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2003, 2004 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 2, 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 COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "tm_p.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "flags.h"
#include "real.h"
#include "insn-config.h"
#include "recog.h"
#include "function.h"
#include "emit-rtl.h"
#include "toplev.h"
#include "output.h"
#include "ggc.h"
#include "hashtab.h"
#include "cselib.h"
#include "params.h"
#include "alloc-pool.h"
static bool cselib_record_memory;
static int entry_and_rtx_equal_p (const void *, const void *);
static hashval_t get_value_hash (const void *);
static struct elt_list *new_elt_list (struct elt_list *, cselib_val *);
static struct elt_loc_list *new_elt_loc_list (struct elt_loc_list *, rtx);
static void unchain_one_value (cselib_val *);
static void unchain_one_elt_list (struct elt_list **);
static void unchain_one_elt_loc_list (struct elt_loc_list **);
static void clear_table (void);
static int discard_useless_locs (void **, void *);
static int discard_useless_values (void **, void *);
static void remove_useless_values (void);
static rtx wrap_constant (enum machine_mode, rtx);
static unsigned int cselib_hash_rtx (rtx, enum machine_mode, int);
static cselib_val *new_cselib_val (unsigned int, enum machine_mode);
static void add_mem_for_addr (cselib_val *, cselib_val *, rtx);
static cselib_val *cselib_lookup_mem (rtx, int);
static void cselib_invalidate_regno (unsigned int, enum machine_mode);
static void cselib_invalidate_mem (rtx);
static void cselib_invalidate_rtx (rtx, rtx, void *);
static void cselib_record_set (rtx, cselib_val *, cselib_val *);
static void cselib_record_sets (rtx);
/* There are three ways in which cselib can look up an rtx:
- for a REG, the reg_values table (which is indexed by regno) is used
- for a MEM, we recursively look up its address and then follow the
addr_list of that value
- for everything else, we compute a hash value and go through the hash
table. Since different rtx's can still have the same hash value,
this involves walking the table entries for a given value and comparing
the locations of the entries with the rtx we are looking up. */
/* A table that enables us to look up elts by their value. */
static htab_t hash_table;
/* This is a global so we don't have to pass this through every function.
It is used in new_elt_loc_list to set SETTING_INSN. */
static rtx cselib_current_insn;
static bool cselib_current_insn_in_libcall;
/* Every new unknown value gets a unique number. */
static unsigned int next_unknown_value;
/* The number of registers we had when the varrays were last resized. */
static unsigned int cselib_nregs;
/* Count values without known locations. Whenever this grows too big, we
remove these useless values from the table. */
static int n_useless_values;
/* Number of useless values before we remove them from the hash table. */
#define MAX_USELESS_VALUES 32
/* This table maps from register number to values. It does not
contain pointers to cselib_val structures, but rather elt_lists.
The purpose is to be able to refer to the same register in
different modes. The first element of the list defines the mode in
which the register was set; if the mode is unknown or the value is
no longer valid in that mode, ELT will be NULL for the first
element. */
struct elt_list **reg_values;
unsigned int reg_values_size;
#define REG_VALUES(i) reg_values[i]
/* The largest number of hard regs used by any entry added to the
REG_VALUES table. Cleared on each clear_table() invocation. */
static unsigned int max_value_regs;
/* Here the set of indices I with REG_VALUES(I) != 0 is saved. This is used
in clear_table() for fast emptying. */
static unsigned int *used_regs;
static unsigned int n_used_regs;
/* We pass this to cselib_invalidate_mem to invalidate all of
memory for a non-const call instruction. */
static GTY(()) rtx callmem;
/* Set by discard_useless_locs if it deleted the last location of any
value. */
static int values_became_useless;
/* Used as stop element of the containing_mem list so we can check
presence in the list by checking the next pointer. */
static cselib_val dummy_val;
/* Used to list all values that contain memory reference.
May or may not contain the useless values - the list is compacted
each time memory is invalidated. */
static cselib_val *first_containing_mem = &dummy_val;
static alloc_pool elt_loc_list_pool, elt_list_pool, cselib_val_pool, value_pool;
/* Allocate a struct elt_list and fill in its two elements with the
arguments. */
static inline struct elt_list *
new_elt_list (struct elt_list *next, cselib_val *elt)
{
struct elt_list *el;
el = pool_alloc (elt_list_pool);
el->next = next;
el->elt = elt;
return el;
}
/* Allocate a struct elt_loc_list and fill in its two elements with the
arguments. */
static inline struct elt_loc_list *
new_elt_loc_list (struct elt_loc_list *next, rtx loc)
{
struct elt_loc_list *el;
el = pool_alloc (elt_loc_list_pool);
el->next = next;
el->loc = loc;
el->setting_insn = cselib_current_insn;
el->in_libcall = cselib_current_insn_in_libcall;
return el;
}
/* The elt_list at *PL is no longer needed. Unchain it and free its
storage. */
static inline void
unchain_one_elt_list (struct elt_list **pl)
{
struct elt_list *l = *pl;
*pl = l->next;
pool_free (elt_list_pool, l);
}
/* Likewise for elt_loc_lists. */
static void
unchain_one_elt_loc_list (struct elt_loc_list **pl)
{
struct elt_loc_list *l = *pl;
*pl = l->next;
pool_free (elt_loc_list_pool, l);
}
/* Likewise for cselib_vals. This also frees the addr_list associated with
V. */
static void
unchain_one_value (cselib_val *v)
{
while (v->addr_list)
unchain_one_elt_list (&v->addr_list);
pool_free (cselib_val_pool, v);
}
/* Remove all entries from the hash table. Also used during
initialization. If CLEAR_ALL isn't set, then only clear the entries
which are known to have been used. */
static void
clear_table (void)
{
unsigned int i;
for (i = 0; i < n_used_regs; i++)
REG_VALUES (used_regs[i]) = 0;
max_value_regs = 0;
n_used_regs = 0;
htab_empty (hash_table);
n_useless_values = 0;
next_unknown_value = 0;
first_containing_mem = &dummy_val;
}
/* The equality test for our hash table. The first argument ENTRY is a table
element (i.e. a cselib_val), while the second arg X is an rtx. We know
that all callers of htab_find_slot_with_hash will wrap CONST_INTs into a
CONST of an appropriate mode. */
static int
entry_and_rtx_equal_p (const void *entry, const void *x_arg)
{
struct elt_loc_list *l;
const cselib_val *v = (const cselib_val *) entry;
rtx x = (rtx) x_arg;
enum machine_mode mode = GET_MODE (x);
gcc_assert (GET_CODE (x) != CONST_INT
&& (mode != VOIDmode || GET_CODE (x) != CONST_DOUBLE));
if (mode != GET_MODE (v->u.val_rtx))
return 0;
/* Unwrap X if necessary. */
if (GET_CODE (x) == CONST
&& (GET_CODE (XEXP (x, 0)) == CONST_INT
|| GET_CODE (XEXP (x, 0)) == CONST_DOUBLE))
x = XEXP (x, 0);
/* We don't guarantee that distinct rtx's have different hash values,
so we need to do a comparison. */
for (l = v->locs; l; l = l->next)
if (rtx_equal_for_cselib_p (l->loc, x))
return 1;
return 0;
}
/* The hash function for our hash table. The value is always computed with
cselib_hash_rtx when adding an element; this function just extracts the
hash value from a cselib_val structure. */
static hashval_t
get_value_hash (const void *entry)
{
const cselib_val *v = (const cselib_val *) entry;
return v->value;
}
/* Return true if X contains a VALUE rtx. If ONLY_USELESS is set, we
only return true for values which point to a cselib_val whose value
element has been set to zero, which implies the cselib_val will be
removed. */
int
references_value_p (rtx x, int only_useless)
{
enum rtx_code code = GET_CODE (x);
const char *fmt = GET_RTX_FORMAT (code);
int i, j;
if (GET_CODE (x) == VALUE
&& (! only_useless || CSELIB_VAL_PTR (x)->locs == 0))
return 1;
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e' && references_value_p (XEXP (x, i), only_useless))
return 1;
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
if (references_value_p (XVECEXP (x, i, j), only_useless))
return 1;
}
return 0;
}
/* For all locations found in X, delete locations that reference useless
values (i.e. values without any location). Called through
htab_traverse. */
static int
discard_useless_locs (void **x, void *info ATTRIBUTE_UNUSED)
{
cselib_val *v = (cselib_val *)*x;
struct elt_loc_list **p = &v->locs;
int had_locs = v->locs != 0;
while (*p)
{
if (references_value_p ((*p)->loc, 1))
unchain_one_elt_loc_list (p);
else
p = &(*p)->next;
}
if (had_locs && v->locs == 0)
{
n_useless_values++;
values_became_useless = 1;
}
return 1;
}
/* If X is a value with no locations, remove it from the hashtable. */
static int
discard_useless_values (void **x, void *info ATTRIBUTE_UNUSED)
{
cselib_val *v = (cselib_val *)*x;
if (v->locs == 0)
{
CSELIB_VAL_PTR (v->u.val_rtx) = NULL;
htab_clear_slot (hash_table, x);
unchain_one_value (v);
n_useless_values--;
}
return 1;
}
/* Clean out useless values (i.e. those which no longer have locations
associated with them) from the hash table. */
static void
remove_useless_values (void)
{
cselib_val **p, *v;
/* First pass: eliminate locations that reference the value. That in
turn can make more values useless. */
do
{
values_became_useless = 0;
htab_traverse (hash_table, discard_useless_locs, 0);
}
while (values_became_useless);
/* Second pass: actually remove the values. */
p = &first_containing_mem;
for (v = *p; v != &dummy_val; v = v->next_containing_mem)
if (v->locs)
{
*p = v;
p = &(*p)->next_containing_mem;
}
*p = &dummy_val;
htab_traverse (hash_table, discard_useless_values, 0);
gcc_assert (!n_useless_values);
}
/* Return the mode in which a register was last set. If X is not a
register, return its mode. If the mode in which the register was
set is not known, or the value was already clobbered, return
VOIDmode. */
enum machine_mode
cselib_reg_set_mode (rtx x)
{
if (!REG_P (x))
return GET_MODE (x);
if (REG_VALUES (REGNO (x)) == NULL
|| REG_VALUES (REGNO (x))->elt == NULL)
return VOIDmode;
return GET_MODE (REG_VALUES (REGNO (x))->elt->u.val_rtx);
}
/* Return nonzero if we can prove that X and Y contain the same value, taking
our gathered information into account. */
int
rtx_equal_for_cselib_p (rtx x, rtx y)
{
enum rtx_code code;
const char *fmt;
int i;
if (REG_P (x) || MEM_P (x))
{
cselib_val *e = cselib_lookup (x, GET_MODE (x), 0);
if (e)
x = e->u.val_rtx;
}
if (REG_P (y) || MEM_P (y))
{
cselib_val *e = cselib_lookup (y, GET_MODE (y), 0);
if (e)
y = e->u.val_rtx;
}
if (x == y)
return 1;
if (GET_CODE (x) == VALUE && GET_CODE (y) == VALUE)
return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y);
if (GET_CODE (x) == VALUE)
{
cselib_val *e = CSELIB_VAL_PTR (x);
struct elt_loc_list *l;
for (l = e->locs; l; l = l->next)
{
rtx t = l->loc;
/* Avoid infinite recursion. */
if (REG_P (t) || MEM_P (t))
continue;
else if (rtx_equal_for_cselib_p (t, y))
return 1;
}
return 0;
}
if (GET_CODE (y) == VALUE)
{
cselib_val *e = CSELIB_VAL_PTR (y);
struct elt_loc_list *l;
for (l = e->locs; l; l = l->next)
{
rtx t = l->loc;
if (REG_P (t) || MEM_P (t))
continue;
else if (rtx_equal_for_cselib_p (x, t))
return 1;
}
return 0;
}
if (GET_CODE (x) != GET_CODE (y) || GET_MODE (x) != GET_MODE (y))
return 0;
/* This won't be handled correctly by the code below. */
if (GET_CODE (x) == LABEL_REF)
return XEXP (x, 0) == XEXP (y, 0);
code = GET_CODE (x);
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
int j;
switch (fmt[i])
{
case 'w':
if (XWINT (x, i) != XWINT (y, i))
return 0;
break;
case 'n':
case 'i':
if (XINT (x, i) != XINT (y, i))
return 0;
break;
case 'V':
case 'E':
/* Two vectors must have the same length. */
if (XVECLEN (x, i) != XVECLEN (y, i))
return 0;
/* And the corresponding elements must match. */
for (j = 0; j < XVECLEN (x, i); j++)
if (! rtx_equal_for_cselib_p (XVECEXP (x, i, j),
XVECEXP (y, i, j)))
return 0;
break;
case 'e':
if (! rtx_equal_for_cselib_p (XEXP (x, i), XEXP (y, i)))
return 0;
break;
case 'S':
case 's':
if (strcmp (XSTR (x, i), XSTR (y, i)))
return 0;
break;
case 'u':
/* These are just backpointers, so they don't matter. */
break;
case '0':
case 't':
break;
/* It is believed that rtx's at this level will never
contain anything but integers and other rtx's,
except for within LABEL_REFs and SYMBOL_REFs. */
default:
gcc_unreachable ();
}
}
return 1;
}
/* We need to pass down the mode of constants through the hash table
functions. For that purpose, wrap them in a CONST of the appropriate
mode. */
static rtx
wrap_constant (enum machine_mode mode, rtx x)
{
if (GET_CODE (x) != CONST_INT
&& (GET_CODE (x) != CONST_DOUBLE || GET_MODE (x) != VOIDmode))
return x;
gcc_assert (mode != VOIDmode);
return gen_rtx_CONST (mode, x);
}
/* Hash an rtx. Return 0 if we couldn't hash the rtx.
For registers and memory locations, we look up their cselib_val structure
and return its VALUE element.
Possible reasons for return 0 are: the object is volatile, or we couldn't
find a register or memory location in the table and CREATE is zero. If
CREATE is nonzero, table elts are created for regs and mem.
MODE is used in hashing for CONST_INTs only;
otherwise the mode of X is used. */
static unsigned int
cselib_hash_rtx (rtx x, enum machine_mode mode, int create)
{
cselib_val *e;
int i, j;
enum rtx_code code;
const char *fmt;
unsigned int hash = 0;
code = GET_CODE (x);
hash += (unsigned) code + (unsigned) GET_MODE (x);
switch (code)
{
case MEM:
case REG:
e = cselib_lookup (x, GET_MODE (x), create);
if (! e)
return 0;
return e->value;
case CONST_INT:
hash += ((unsigned) CONST_INT << 7) + (unsigned) mode + INTVAL (x);
return hash ? hash : (unsigned int) CONST_INT;
case CONST_DOUBLE:
/* This is like the general case, except that it only counts
the integers representing the constant. */
hash += (unsigned) code + (unsigned) GET_MODE (x);
if (GET_MODE (x) != VOIDmode)
hash += real_hash (CONST_DOUBLE_REAL_VALUE (x));
else
hash += ((unsigned) CONST_DOUBLE_LOW (x)
+ (unsigned) CONST_DOUBLE_HIGH (x));
return hash ? hash : (unsigned int) CONST_DOUBLE;
case CONST_VECTOR:
{
int units;
rtx elt;
units = CONST_VECTOR_NUNITS (x);
for (i = 0; i < units; ++i)
{
elt = CONST_VECTOR_ELT (x, i);
hash += cselib_hash_rtx (elt, GET_MODE (elt), 0);
}
return hash;
}
/* Assume there is only one rtx object for any given label. */
case LABEL_REF:
hash
+= ((unsigned) LABEL_REF << 7) + (unsigned long) XEXP (x, 0);
return hash ? hash : (unsigned int) LABEL_REF;
case SYMBOL_REF:
hash
+= ((unsigned) SYMBOL_REF << 7) + (unsigned long) XSTR (x, 0);
return hash ? hash : (unsigned int) SYMBOL_REF;
case PRE_DEC:
case PRE_INC:
case POST_DEC:
case POST_INC:
case POST_MODIFY:
case PRE_MODIFY:
case PC:
case CC0:
case CALL:
case UNSPEC_VOLATILE:
return 0;
case ASM_OPERANDS:
if (MEM_VOLATILE_P (x))
return 0;
break;
default:
break;
}
i = GET_RTX_LENGTH (code) - 1;
fmt = GET_RTX_FORMAT (code);
for (; i >= 0; i--)
{
switch (fmt[i])
{
case 'e':
{
rtx tem = XEXP (x, i);
unsigned int tem_hash = cselib_hash_rtx (tem, 0, create);
if (tem_hash == 0)
return 0;
hash += tem_hash;
}
break;
case 'E':
for (j = 0; j < XVECLEN (x, i); j++)
{
unsigned int tem_hash
= cselib_hash_rtx (XVECEXP (x, i, j), 0, create);
if (tem_hash == 0)
return 0;
hash += tem_hash;
}
break;
case 's':
{
const unsigned char *p = (const unsigned char *) XSTR (x, i);
if (p)
while (*p)
hash += *p++;
break;
}
case 'i':
hash += XINT (x, i);
break;
case '0':
case 't':
/* unused */
break;
default:
gcc_unreachable ();
}
}
return hash ? hash : 1 + (unsigned int) GET_CODE (x);
}
/* Create a new value structure for VALUE and initialize it. The mode of the
value is MODE. */
static inline cselib_val *
new_cselib_val (unsigned int value, enum machine_mode mode)
{
cselib_val *e = pool_alloc (cselib_val_pool);
gcc_assert (value);
e->value = value;
/* We use custom method to allocate this RTL construct because it accounts
about 8% of overall memory usage. */
e->u.val_rtx = pool_alloc (value_pool);
memset (e->u.val_rtx, 0, RTX_HDR_SIZE);
PUT_CODE (e->u.val_rtx, VALUE);
PUT_MODE (e->u.val_rtx, mode);
CSELIB_VAL_PTR (e->u.val_rtx) = e;
e->addr_list = 0;
e->locs = 0;
e->next_containing_mem = 0;
return e;
}
/* ADDR_ELT is a value that is used as address. MEM_ELT is the value that
contains the data at this address. X is a MEM that represents the
value. Update the two value structures to represent this situation. */
static void
add_mem_for_addr (cselib_val *addr_elt, cselib_val *mem_elt, rtx x)
{
struct elt_loc_list *l;
/* Avoid duplicates. */
for (l = mem_elt->locs; l; l = l->next)
if (MEM_P (l->loc)
&& CSELIB_VAL_PTR (XEXP (l->loc, 0)) == addr_elt)
return;
addr_elt->addr_list = new_elt_list (addr_elt->addr_list, mem_elt);
mem_elt->locs
= new_elt_loc_list (mem_elt->locs,
replace_equiv_address_nv (x, addr_elt->u.val_rtx));
if (mem_elt->next_containing_mem == NULL)
{
mem_elt->next_containing_mem = first_containing_mem;
first_containing_mem = mem_elt;
}
}
/* Subroutine of cselib_lookup. Return a value for X, which is a MEM rtx.
If CREATE, make a new one if we haven't seen it before. */
static cselib_val *
cselib_lookup_mem (rtx x, int create)
{
enum machine_mode mode = GET_MODE (x);
void **slot;
cselib_val *addr;
cselib_val *mem_elt;
struct elt_list *l;
if (MEM_VOLATILE_P (x) || mode == BLKmode
|| !cselib_record_memory
|| (FLOAT_MODE_P (mode) && flag_float_store))
return 0;
/* Look up the value for the address. */
addr = cselib_lookup (XEXP (x, 0), mode, create);
if (! addr)
return 0;
/* Find a value that describes a value of our mode at that address. */
for (l = addr->addr_list; l; l = l->next)
if (GET_MODE (l->elt->u.val_rtx) == mode)
return l->elt;
if (! create)
return 0;
mem_elt = new_cselib_val (++next_unknown_value, mode);
add_mem_for_addr (addr, mem_elt, x);
slot = htab_find_slot_with_hash (hash_table, wrap_constant (mode, x),
mem_elt->value, INSERT);
*slot = mem_elt;
return mem_elt;
}
/* Walk rtx X and replace all occurrences of REG and MEM subexpressions
with VALUE expressions. This way, it becomes independent of changes
to registers and memory.
X isn't actually modified; if modifications are needed, new rtl is
allocated. However, the return value can share rtl with X. */
rtx
cselib_subst_to_values (rtx x)
{
enum rtx_code code = GET_CODE (x);
const char *fmt = GET_RTX_FORMAT (code);
cselib_val *e;
struct elt_list *l;
rtx copy = x;
int i;
switch (code)
{
case REG:
l = REG_VALUES (REGNO (x));
if (l && l->elt == NULL)
l = l->next;
for (; l; l = l->next)
if (GET_MODE (l->elt->u.val_rtx) == GET_MODE (x))
return l->elt->u.val_rtx;
gcc_unreachable ();
case MEM:
e = cselib_lookup_mem (x, 0);
if (! e)
{
/* This happens for autoincrements. Assign a value that doesn't
match any other. */
e = new_cselib_val (++next_unknown_value, GET_MODE (x));
}
return e->u.val_rtx;
case CONST_DOUBLE:
case CONST_VECTOR:
case CONST_INT:
return x;
case POST_INC:
case PRE_INC:
case POST_DEC:
case PRE_DEC:
case POST_MODIFY:
case PRE_MODIFY:
e = new_cselib_val (++next_unknown_value, GET_MODE (x));
return e->u.val_rtx;
default:
break;
}
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
{
rtx t = cselib_subst_to_values (XEXP (x, i));
if (t != XEXP (x, i) && x == copy)
copy = shallow_copy_rtx (x);
XEXP (copy, i) = t;
}
else if (fmt[i] == 'E')
{
int j, k;
for (j = 0; j < XVECLEN (x, i); j++)
{
rtx t = cselib_subst_to_values (XVECEXP (x, i, j));
if (t != XVECEXP (x, i, j) && XVEC (x, i) == XVEC (copy, i))
{
if (x == copy)
copy = shallow_copy_rtx (x);
XVEC (copy, i) = rtvec_alloc (XVECLEN (x, i));
for (k = 0; k < j; k++)
XVECEXP (copy, i, k) = XVECEXP (x, i, k);
}
XVECEXP (copy, i, j) = t;
}
}
}
return copy;
}
/* Look up the rtl expression X in our tables and return the value it has.
If CREATE is zero, we return NULL if we don't know the value. Otherwise,
we create a new one if possible, using mode MODE if X doesn't have a mode
(i.e. because it's a constant). */
cselib_val *
cselib_lookup (rtx x, enum machine_mode mode, int create)
{
void **slot;
cselib_val *e;
unsigned int hashval;
if (GET_MODE (x) != VOIDmode)
mode = GET_MODE (x);
if (GET_CODE (x) == VALUE)
return CSELIB_VAL_PTR (x);
if (REG_P (x))
{
struct elt_list *l;
unsigned int i = REGNO (x);
l = REG_VALUES (i);
if (l && l->elt == NULL)
l = l->next;
for (; l; l = l->next)
if (mode == GET_MODE (l->elt->u.val_rtx))
return l->elt;
if (! create)
return 0;
if (i < FIRST_PSEUDO_REGISTER)
{
unsigned int n = hard_regno_nregs[i][mode];
if (n > max_value_regs)
max_value_regs = n;
}
e = new_cselib_val (++next_unknown_value, GET_MODE (x));
e->locs = new_elt_loc_list (e->locs, x);
if (REG_VALUES (i) == 0)
{
/* Maintain the invariant that the first entry of
REG_VALUES, if present, must be the value used to set the
register, or NULL. */
used_regs[n_used_regs++] = i;
REG_VALUES (i) = new_elt_list (REG_VALUES (i), NULL);
}
REG_VALUES (i)->next = new_elt_list (REG_VALUES (i)->next, e);
slot = htab_find_slot_with_hash (hash_table, x, e->value, INSERT);
*slot = e;
return e;
}
if (MEM_P (x))
return cselib_lookup_mem (x, create);
hashval = cselib_hash_rtx (x, mode, create);
/* Can't even create if hashing is not possible. */
if (! hashval)
return 0;
slot = htab_find_slot_with_hash (hash_table, wrap_constant (mode, x),
hashval, create ? INSERT : NO_INSERT);
if (slot == 0)
return 0;
e = (cselib_val *) *slot;
if (e)
return e;
e = new_cselib_val (hashval, mode);
/* We have to fill the slot before calling cselib_subst_to_values:
the hash table is inconsistent until we do so, and
cselib_subst_to_values will need to do lookups. */
*slot = (void *) e;
e->locs = new_elt_loc_list (e->locs, cselib_subst_to_values (x));
return e;
}
/* Invalidate any entries in reg_values that overlap REGNO. This is called
if REGNO is changing. MODE is the mode of the assignment to REGNO, which
is used to determine how many hard registers are being changed. If MODE
is VOIDmode, then only REGNO is being changed; this is used when
invalidating call clobbered registers across a call. */
static void
cselib_invalidate_regno (unsigned int regno, enum machine_mode mode)
{
unsigned int endregno;
unsigned int i;
/* If we see pseudos after reload, something is _wrong_. */
gcc_assert (!reload_completed || regno < FIRST_PSEUDO_REGISTER
|| reg_renumber[regno] < 0);
/* Determine the range of registers that must be invalidated. For
pseudos, only REGNO is affected. For hard regs, we must take MODE
into account, and we must also invalidate lower register numbers
if they contain values that overlap REGNO. */
if (regno < FIRST_PSEUDO_REGISTER)
{
gcc_assert (mode != VOIDmode);
if (regno < max_value_regs)
i = 0;
else
i = regno - max_value_regs;
endregno = regno + hard_regno_nregs[regno][mode];
}
else
{
i = regno;
endregno = regno + 1;
}
for (; i < endregno; i++)
{
struct elt_list **l = ®_VALUES (i);
/* Go through all known values for this reg; if it overlaps the range
we're invalidating, remove the value. */
while (*l)
{
cselib_val *v = (*l)->elt;
struct elt_loc_list **p;
unsigned int this_last = i;
if (i < FIRST_PSEUDO_REGISTER && v != NULL)
this_last += hard_regno_nregs[i][GET_MODE (v->u.val_rtx)] - 1;
if (this_last < regno || v == NULL)
{
l = &(*l)->next;
continue;
}
/* We have an overlap. */
if (*l == REG_VALUES (i))
{
/* Maintain the invariant that the first entry of
REG_VALUES, if present, must be the value used to set
the register, or NULL. This is also nice because
then we won't push the same regno onto user_regs
multiple times. */
(*l)->elt = NULL;
l = &(*l)->next;
}
else
unchain_one_elt_list (l);
/* Now, we clear the mapping from value to reg. It must exist, so
this code will crash intentionally if it doesn't. */
for (p = &v->locs; ; p = &(*p)->next)
{
rtx x = (*p)->loc;
if (REG_P (x) && REGNO (x) == i)
{
unchain_one_elt_loc_list (p);
break;
}
}
if (v->locs == 0)
n_useless_values++;
}
}
}
/* Return 1 if X has a value that can vary even between two
executions of the program. 0 means X can be compared reliably
against certain constants or near-constants. */
static int
cselib_rtx_varies_p (rtx x ATTRIBUTE_UNUSED, int from_alias ATTRIBUTE_UNUSED)
{
/* We actually don't need to verify very hard. This is because
if X has actually changed, we invalidate the memory anyway,
so assume that all common memory addresses are
invariant. */
return 0;
}
/* Invalidate any locations in the table which are changed because of a
store to MEM_RTX. If this is called because of a non-const call
instruction, MEM_RTX is (mem:BLK const0_rtx). */
static void
cselib_invalidate_mem (rtx mem_rtx)
{
cselib_val **vp, *v, *next;
int num_mems = 0;
rtx mem_addr;
mem_addr = canon_rtx (get_addr (XEXP (mem_rtx, 0)));
mem_rtx = canon_rtx (mem_rtx);
vp = &first_containing_mem;
for (v = *vp; v != &dummy_val; v = next)
{
bool has_mem = false;
struct elt_loc_list **p = &v->locs;
int had_locs = v->locs != 0;
while (*p)
{
rtx x = (*p)->loc;
cselib_val *addr;
struct elt_list **mem_chain;
/* MEMs may occur in locations only at the top level; below
that every MEM or REG is substituted by its VALUE. */
if (!MEM_P (x))
{
p = &(*p)->next;
continue;
}
if (num_mems < PARAM_VALUE (PARAM_MAX_CSELIB_MEMORY_LOCATIONS)
&& ! canon_true_dependence (mem_rtx, GET_MODE (mem_rtx), mem_addr,
x, cselib_rtx_varies_p))
{
has_mem = true;
num_mems++;
p = &(*p)->next;
continue;
}
/* This one overlaps. */
/* We must have a mapping from this MEM's address to the
value (E). Remove that, too. */
addr = cselib_lookup (XEXP (x, 0), VOIDmode, 0);
mem_chain = &addr->addr_list;
for (;;)
{
if ((*mem_chain)->elt == v)
{
unchain_one_elt_list (mem_chain);
break;
}
mem_chain = &(*mem_chain)->next;
}
unchain_one_elt_loc_list (p);
}
if (had_locs && v->locs == 0)
n_useless_values++;
next = v->next_containing_mem;
if (has_mem)
{
*vp = v;
vp = &(*vp)->next_containing_mem;
}
else
v->next_containing_mem = NULL;
}
*vp = &dummy_val;
}
/* Invalidate DEST, which is being assigned to or clobbered. The second and
the third parameter exist so that this function can be passed to
note_stores; they are ignored. */
static void
cselib_invalidate_rtx (rtx dest, rtx ignore ATTRIBUTE_UNUSED,
void *data ATTRIBUTE_UNUSED)
{
while (GET_CODE (dest) == STRICT_LOW_PART || GET_CODE (dest) == SIGN_EXTRACT
|| GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SUBREG)
dest = XEXP (dest, 0);
if (REG_P (dest))
cselib_invalidate_regno (REGNO (dest), GET_MODE (dest));
else if (MEM_P (dest))
cselib_invalidate_mem (dest);
/* Some machines don't define AUTO_INC_DEC, but they still use push
instructions. We need to catch that case here in order to
invalidate the stack pointer correctly. Note that invalidating
the stack pointer is different from invalidating DEST. */
if (push_operand (dest, GET_MODE (dest)))
cselib_invalidate_rtx (stack_pointer_rtx, NULL_RTX, NULL);
}
/* Record the result of a SET instruction. DEST is being set; the source
contains the value described by SRC_ELT. If DEST is a MEM, DEST_ADDR_ELT
describes its address. */
static void
cselib_record_set (rtx dest, cselib_val *src_elt, cselib_val *dest_addr_elt)
{
int dreg = REG_P (dest) ? (int) REGNO (dest) : -1;
if (src_elt == 0 || side_effects_p (dest))
return;
if (dreg >= 0)
{
if (dreg < FIRST_PSEUDO_REGISTER)
{
unsigned int n = hard_regno_nregs[dreg][GET_MODE (dest)];
if (n > max_value_regs)
max_value_regs = n;
}
if (REG_VALUES (dreg) == 0)
{
used_regs[n_used_regs++] = dreg;
REG_VALUES (dreg) = new_elt_list (REG_VALUES (dreg), src_elt);
}
else
{
/* The register should have been invalidated. */
gcc_assert (REG_VALUES (dreg)->elt == 0);
REG_VALUES (dreg)->elt = src_elt;
}
if (src_elt->locs == 0)
n_useless_values--;
src_elt->locs = new_elt_loc_list (src_elt->locs, dest);
}
else if (MEM_P (dest) && dest_addr_elt != 0
&& cselib_record_memory)
{
if (src_elt->locs == 0)
n_useless_values--;
add_mem_for_addr (dest_addr_elt, src_elt, dest);
}
}
/* Describe a single set that is part of an insn. */
struct set
{
rtx src;
rtx dest;
cselib_val *src_elt;
cselib_val *dest_addr_elt;
};
/* There is no good way to determine how many elements there can be
in a PARALLEL. Since it's fairly cheap, use a really large number. */
#define MAX_SETS (FIRST_PSEUDO_REGISTER * 2)
/* Record the effects of any sets in INSN. */
static void
cselib_record_sets (rtx insn)
{
int n_sets = 0;
int i;
struct set sets[MAX_SETS];
rtx body = PATTERN (insn);
rtx cond = 0;
body = PATTERN (insn);
if (GET_CODE (body) == COND_EXEC)
{
cond = COND_EXEC_TEST (body);
body = COND_EXEC_CODE (body);
}
/* Find all sets. */
if (GET_CODE (body) == SET)
{
sets[0].src = SET_SRC (body);
sets[0].dest = SET_DEST (body);
n_sets = 1;
}
else if (GET_CODE (body) == PARALLEL)
{
/* Look through the PARALLEL and record the values being
set, if possible. Also handle any CLOBBERs. */
for (i = XVECLEN (body, 0) - 1; i >= 0; --i)
{
rtx x = XVECEXP (body, 0, i);
if (GET_CODE (x) == SET)
{
sets[n_sets].src = SET_SRC (x);
sets[n_sets].dest = SET_DEST (x);
n_sets++;
}
}
}
/* Look up the values that are read. Do this before invalidating the
locations that are written. */
for (i = 0; i < n_sets; i++)
{
rtx dest = sets[i].dest;
/* A STRICT_LOW_PART can be ignored; we'll record the equivalence for
the low part after invalidating any knowledge about larger modes. */
if (GET_CODE (sets[i].dest) == STRICT_LOW_PART)
sets[i].dest = dest = XEXP (dest, 0);
/* We don't know how to record anything but REG or MEM. */
if (REG_P (dest)
|| (MEM_P (dest) && cselib_record_memory))
{
rtx src = sets[i].src;
if (cond)
src = gen_rtx_IF_THEN_ELSE (GET_MODE (src), cond, src, dest);
sets[i].src_elt = cselib_lookup (src, GET_MODE (dest), 1);
if (MEM_P (dest))
sets[i].dest_addr_elt = cselib_lookup (XEXP (dest, 0), Pmode, 1);
else
sets[i].dest_addr_elt = 0;
}
}
/* Invalidate all locations written by this insn. Note that the elts we
looked up in the previous loop aren't affected, just some of their
locations may go away. */
note_stores (body, cselib_invalidate_rtx, NULL);
/* If this is an asm, look for duplicate sets. This can happen when the
user uses the same value as an output multiple times. This is valid
if the outputs are not actually used thereafter. Treat this case as
if the value isn't actually set. We do this by smashing the destination
to pc_rtx, so that we won't record the value later. */
if (n_sets >= 2 && asm_noperands (body) >= 0)
{
for (i = 0; i < n_sets; i++)
{
rtx dest = sets[i].dest;
if (REG_P (dest) || MEM_P (dest))
{
int j;
for (j = i + 1; j < n_sets; j++)
if (rtx_equal_p (dest, sets[j].dest))
{
sets[i].dest = pc_rtx;
sets[j].dest = pc_rtx;
}
}
}
}
/* Now enter the equivalences in our tables. */
for (i = 0; i < n_sets; i++)
{
rtx dest = sets[i].dest;
if (REG_P (dest)
|| (MEM_P (dest) && cselib_record_memory))
cselib_record_set (dest, sets[i].src_elt, sets[i].dest_addr_elt);
}
}
/* Record the effects of INSN. */
void
cselib_process_insn (rtx insn)
{
int i;
rtx x;
if (find_reg_note (insn, REG_LIBCALL, NULL))
cselib_current_insn_in_libcall = true;
if (find_reg_note (insn, REG_RETVAL, NULL))
cselib_current_insn_in_libcall = false;
cselib_current_insn = insn;
/* Forget everything at a CODE_LABEL, a volatile asm, or a setjmp. */
if (LABEL_P (insn)
|| (CALL_P (insn)
&& find_reg_note (insn, REG_SETJMP, NULL))
|| (NONJUMP_INSN_P (insn)
&& GET_CODE (PATTERN (insn)) == ASM_OPERANDS
&& MEM_VOLATILE_P (PATTERN (insn))))
{
clear_table ();
return;
}
if (! INSN_P (insn))
{
cselib_current_insn = 0;
return;
}
/* If this is a call instruction, forget anything stored in a
call clobbered register, or, if this is not a const call, in
memory. */
if (CALL_P (insn))
{
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (call_used_regs[i])
cselib_invalidate_regno (i, reg_raw_mode[i]);
if (! CONST_OR_PURE_CALL_P (insn))
cselib_invalidate_mem (callmem);
}
cselib_record_sets (insn);
#ifdef AUTO_INC_DEC
/* Clobber any registers which appear in REG_INC notes. We
could keep track of the changes to their values, but it is
unlikely to help. */
for (x = REG_NOTES (insn); x; x = XEXP (x, 1))
if (REG_NOTE_KIND (x) == REG_INC)
cselib_invalidate_rtx (XEXP (x, 0), NULL_RTX, NULL);
#endif
/* Look for any CLOBBERs in CALL_INSN_FUNCTION_USAGE, but only
after we have processed the insn. */
if (CALL_P (insn))
for (x = CALL_INSN_FUNCTION_USAGE (insn); x; x = XEXP (x, 1))
if (GET_CODE (XEXP (x, 0)) == CLOBBER)
cselib_invalidate_rtx (XEXP (XEXP (x, 0), 0), NULL_RTX, NULL);
cselib_current_insn = 0;
if (n_useless_values > MAX_USELESS_VALUES)
remove_useless_values ();
}
/* Initialize cselib for one pass. The caller must also call
init_alias_analysis. */
void
cselib_init (bool record_memory)
{
elt_list_pool = create_alloc_pool ("elt_list",
sizeof (struct elt_list), 10);
elt_loc_list_pool = create_alloc_pool ("elt_loc_list",
sizeof (struct elt_loc_list), 10);
cselib_val_pool = create_alloc_pool ("cselib_val_list",
sizeof (cselib_val), 10);
value_pool = create_alloc_pool ("value",
RTX_SIZE (VALUE), 100);
cselib_record_memory = record_memory;
/* This is only created once. */
if (! callmem)
callmem = gen_rtx_MEM (BLKmode, const0_rtx);
cselib_nregs = max_reg_num ();
/* We preserve reg_values to allow expensive clearing of the whole thing.
Reallocate it however if it happens to be too large. */
if (!reg_values || reg_values_size < cselib_nregs
|| (reg_values_size > 10 && reg_values_size > cselib_nregs * 4))
{
if (reg_values)
free (reg_values);
/* Some space for newly emit instructions so we don't end up
reallocating in between passes. */
reg_values_size = cselib_nregs + (63 + cselib_nregs) / 16;
reg_values = xcalloc (reg_values_size, sizeof (reg_values));
}
used_regs = xmalloc (sizeof (*used_regs) * cselib_nregs);
n_used_regs = 0;
hash_table = htab_create (31, get_value_hash, entry_and_rtx_equal_p, NULL);
cselib_current_insn_in_libcall = false;
}
/* Called when the current user is done with cselib. */
void
cselib_finish (void)
{
free_alloc_pool (elt_list_pool);
free_alloc_pool (elt_loc_list_pool);
free_alloc_pool (cselib_val_pool);
free_alloc_pool (value_pool);
clear_table ();
htab_delete (hash_table);
free (used_regs);
used_regs = 0;
hash_table = 0;
n_useless_values = 0;
next_unknown_value = 0;
}
#include "gt-cselib.h"
|