summaryrefslogtreecommitdiffstats
path: root/contrib/gcc/df-scan.c
blob: 46dfb072cce43fb561134e1950cfac56f14166af (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
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
/* FIXME: We need to go back and add the warning messages about code
   moved across setjmp.  */


/* Scanning of rtl for dataflow analysis.
   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
   Free Software Foundation, Inc.
   Originally contributed by Michael P. Hayes 
             (m.hayes@elec.canterbury.ac.nz, mhayes@redhat.com)
   Major rewrite contributed by Danny Berlin (dberlin@dberlin.org)
             and Kenneth Zadeck (zadeck@naturalbridge.com).

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, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.
*/

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "tm_p.h"
#include "insn-config.h"
#include "recog.h"
#include "function.h"
#include "regs.h"
#include "output.h"
#include "alloc-pool.h"
#include "flags.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "sbitmap.h"
#include "bitmap.h"
#include "timevar.h"
#include "tree.h"
#include "target.h"
#include "target-def.h"
#include "df.h"

#ifndef HAVE_epilogue
#define HAVE_epilogue 0
#endif
#ifndef HAVE_prologue
#define HAVE_prologue 0
#endif
#ifndef HAVE_sibcall_epilogue
#define HAVE_sibcall_epilogue 0
#endif

#ifndef EPILOGUE_USES
#define EPILOGUE_USES(REGNO)  0
#endif

/* 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;

/* The set of hard registers in eliminables[i].from. */

static HARD_REG_SET elim_reg_set;

/* This is a bitmap copy of regs_invalidated_by_call so that we can
   easily add it into bitmaps, etc. */ 

bitmap df_invalidated_by_call = NULL;

/* Initialize ur_in and ur_out as if all hard registers were partially
   available.  */

static void df_ref_record (struct dataflow *, rtx, rtx *, 
			   basic_block, rtx, enum df_ref_type,
			   enum df_ref_flags, bool record_live);
static void df_def_record_1 (struct dataflow *, rtx, basic_block, rtx,
			     enum df_ref_flags, bool record_live);
static void df_defs_record (struct dataflow *, rtx, basic_block, rtx);
static void df_uses_record (struct dataflow *, rtx *, enum df_ref_type,
			    basic_block, rtx, enum df_ref_flags);

static void df_insn_refs_record (struct dataflow *, basic_block, rtx);
static void df_bb_refs_record (struct dataflow *, basic_block);
static void df_refs_record (struct dataflow *, bitmap);
static struct df_ref *df_ref_create_structure (struct dataflow *, rtx, rtx *, 
					       basic_block, rtx, enum df_ref_type, 
					       enum df_ref_flags);
static void df_record_entry_block_defs (struct dataflow *);
static void df_record_exit_block_uses (struct dataflow *);
static void df_grow_reg_info (struct dataflow *, struct df_ref_info *);
static void df_grow_ref_info (struct df_ref_info *, unsigned int);
static void df_grow_insn_info (struct df *);


/*----------------------------------------------------------------------------
   SCANNING DATAFLOW PROBLEM

   There are several ways in which scanning looks just like the other
   dataflow problems.  It shares the all the mechanisms for local info
   as well as basic block info.  Where it differs is when and how often
   it gets run.  It also has no need for the iterative solver.
----------------------------------------------------------------------------*/

/* Problem data for the scanning dataflow function.  */
struct df_scan_problem_data
{
  alloc_pool ref_pool;
  alloc_pool insn_pool;
  alloc_pool reg_pool;
  alloc_pool mw_reg_pool;
  alloc_pool mw_link_pool;
};

typedef struct df_scan_bb_info *df_scan_bb_info_t;

static void 
df_scan_free_internal (struct dataflow *dflow)
{
  struct df *df = dflow->df;
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;

  free (df->def_info.regs);
  free (df->def_info.refs);
  memset (&df->def_info, 0, (sizeof (struct df_ref_info)));

  free (df->use_info.regs);
  free (df->use_info.refs);
  memset (&df->use_info, 0, (sizeof (struct df_ref_info)));

  free (df->insns);
  df->insns = NULL;
  df->insns_size = 0;

  free (dflow->block_info);
  dflow->block_info = NULL;
  dflow->block_info_size = 0;

  BITMAP_FREE (df->hardware_regs_used);
  BITMAP_FREE (df->entry_block_defs);
  BITMAP_FREE (df->exit_block_uses);

  free_alloc_pool (dflow->block_pool);
  free_alloc_pool (problem_data->ref_pool);
  free_alloc_pool (problem_data->insn_pool);
  free_alloc_pool (problem_data->reg_pool);
  free_alloc_pool (problem_data->mw_reg_pool);
  free_alloc_pool (problem_data->mw_link_pool);
}


/* Get basic block info.  */

struct df_scan_bb_info *
df_scan_get_bb_info (struct dataflow *dflow, unsigned int index)
{
  gcc_assert (index < dflow->block_info_size); 
  return (struct df_scan_bb_info *) dflow->block_info[index];
}


/* Set basic block info.  */

static void
df_scan_set_bb_info (struct dataflow *dflow, unsigned int index, 
		     struct df_scan_bb_info *bb_info)
{
  gcc_assert (index < dflow->block_info_size); 
  dflow->block_info[index] = (void *) bb_info;
}


/* Free basic block info.  */

static void
df_scan_free_bb_info (struct dataflow *dflow, basic_block bb, void *vbb_info)
{
  struct df_scan_bb_info *bb_info = (struct df_scan_bb_info *) vbb_info;
  if (bb_info)
    {
      df_bb_refs_delete (dflow, bb->index);
      pool_free (dflow->block_pool, bb_info);
    }
}


/* Allocate the problem data for the scanning problem.  This should be
   called when the problem is created or when the entire function is to
   be rescanned.  */

static void 
df_scan_alloc (struct dataflow *dflow, bitmap blocks_to_rescan, 
	       bitmap all_blocks ATTRIBUTE_UNUSED)
{
  struct df *df = dflow->df;
  struct df_scan_problem_data *problem_data;
  unsigned int insn_num = get_max_uid () + 1;
  unsigned int block_size = 50;
  unsigned int bb_index;
  bitmap_iterator bi;

  /* Given the number of pools, this is really faster than tearing
     everything apart.  */
  if (dflow->problem_data)
    df_scan_free_internal (dflow);

  dflow->block_pool 
    = create_alloc_pool ("df_scan_block pool", 
			 sizeof (struct df_scan_bb_info), 
			 block_size);

  problem_data = XNEW (struct df_scan_problem_data);
  dflow->problem_data = problem_data;

  problem_data->ref_pool 
    = create_alloc_pool ("df_scan_ref pool", 
			 sizeof (struct df_ref), block_size);
  problem_data->insn_pool 
    = create_alloc_pool ("df_scan_insn pool", 
			 sizeof (struct df_insn_info), block_size);
  problem_data->reg_pool 
    = create_alloc_pool ("df_scan_reg pool", 
			 sizeof (struct df_reg_info), block_size);
  problem_data->mw_reg_pool 
    = create_alloc_pool ("df_scan_mw_reg pool", 
			 sizeof (struct df_mw_hardreg), block_size);
  problem_data->mw_link_pool 
    = create_alloc_pool ("df_scan_mw_link pool", 
			 sizeof (struct df_link), block_size);

  insn_num += insn_num / 4; 
  df_grow_reg_info (dflow, &df->def_info);
  df_grow_ref_info (&df->def_info, insn_num);

  df_grow_reg_info (dflow, &df->use_info);
  df_grow_ref_info (&df->use_info, insn_num *2);

  df_grow_insn_info (df);
  df_grow_bb_info (dflow);

  EXECUTE_IF_SET_IN_BITMAP (blocks_to_rescan, 0, bb_index, bi)
    {
      struct df_scan_bb_info *bb_info = df_scan_get_bb_info (dflow, bb_index);
      if (!bb_info)
	{
	  bb_info = (struct df_scan_bb_info *) pool_alloc (dflow->block_pool);
	  df_scan_set_bb_info (dflow, bb_index, bb_info);
	}
      bb_info->artificial_defs = NULL;
      bb_info->artificial_uses = NULL;
    }

  df->hardware_regs_used = BITMAP_ALLOC (NULL);
  df->entry_block_defs = BITMAP_ALLOC (NULL);
  df->exit_block_uses = BITMAP_ALLOC (NULL);
}


/* Free all of the data associated with the scan problem.  */

static void 
df_scan_free (struct dataflow *dflow)
{
  struct df *df = dflow->df;
  
  if (dflow->problem_data)
    {
      df_scan_free_internal (dflow);
      free (dflow->problem_data);
    }

  if (df->blocks_to_scan)
    BITMAP_FREE (df->blocks_to_scan);
  
  if (df->blocks_to_analyze)
    BITMAP_FREE (df->blocks_to_analyze);

  free (dflow);
}

static void 
df_scan_dump (struct dataflow *dflow ATTRIBUTE_UNUSED, FILE *file ATTRIBUTE_UNUSED)
{
  struct df *df = dflow->df;
  int i;

  fprintf (file, "  invalidated by call \t");
  dump_bitmap (file, df_invalidated_by_call);
  fprintf (file, "  hardware regs used \t");
  dump_bitmap (file, df->hardware_regs_used);
  fprintf (file, "  entry block uses \t");
  dump_bitmap (file, df->entry_block_defs);
  fprintf (file, "  exit block uses \t");
  dump_bitmap (file, df->exit_block_uses);
  fprintf (file, "  regs ever live \t");
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    if (regs_ever_live[i])
      fprintf (file, "%d ", i);
  fprintf (file, "\n");
}

static struct df_problem problem_SCAN =
{
  DF_SCAN,                    /* Problem id.  */
  DF_NONE,                    /* Direction.  */
  df_scan_alloc,              /* Allocate the problem specific data.  */
  NULL,                       /* Reset global information.  */
  df_scan_free_bb_info,       /* Free basic block info.  */
  NULL,                       /* Local compute function.  */
  NULL,                       /* Init the solution specific data.  */
  NULL,                       /* Iterative solver.  */
  NULL,                       /* Confluence operator 0.  */ 
  NULL,                       /* Confluence operator n.  */ 
  NULL,                       /* Transfer function.  */
  NULL,                       /* Finalize function.  */
  df_scan_free,               /* Free all of the problem information.  */
  df_scan_dump,               /* Debugging.  */
  NULL,                       /* Dependent problem.  */
  0                           /* Changeable flags.  */
};


/* Create a new DATAFLOW instance and add it to an existing instance
   of DF.  The returned structure is what is used to get at the
   solution.  */

struct dataflow *
df_scan_add_problem (struct df *df, int flags)
{
  return df_add_problem (df, &problem_SCAN, flags);
}

/*----------------------------------------------------------------------------
   Storage Allocation Utilities
----------------------------------------------------------------------------*/


/* First, grow the reg_info information.  If the current size is less than
   the number of psuedos, grow to 25% more than the number of
   pseudos.  

   Second, assure that all of the slots up to max_reg_num have been
   filled with reg_info structures.  */

static void 
df_grow_reg_info (struct dataflow *dflow, struct df_ref_info *ref_info)
{
  unsigned int max_reg = max_reg_num ();
  unsigned int new_size = max_reg;
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;
  unsigned int i;

  if (ref_info->regs_size < new_size)
    {
      new_size += new_size / 4;
      ref_info->regs = xrealloc (ref_info->regs, 
				 new_size *sizeof (struct df_reg_info*));
      ref_info->regs_size = new_size;
    }

  for (i = ref_info->regs_inited; i < max_reg; i++)
    {
      struct df_reg_info *reg_info = pool_alloc (problem_data->reg_pool);
      memset (reg_info, 0, sizeof (struct df_reg_info));
      ref_info->regs[i] = reg_info;
    }
  
  ref_info->regs_inited = max_reg;
}


/* Grow the ref information.  */

static void 
df_grow_ref_info (struct df_ref_info *ref_info, unsigned int new_size)
{
  if (ref_info->refs_size < new_size)
    {
      ref_info->refs = xrealloc (ref_info->refs, 
				 new_size *sizeof (struct df_ref *));
      memset (ref_info->refs + ref_info->refs_size, 0,
	      (new_size - ref_info->refs_size) *sizeof (struct df_ref *));
      ref_info->refs_size = new_size;
    }
}


/* Grow the ref information.  If the current size is less than the
   number of instructions, grow to 25% more than the number of
   instructions.  */

static void 
df_grow_insn_info (struct df *df)
{
  unsigned int new_size = get_max_uid () + 1;
  if (df->insns_size < new_size)
    {
      new_size += new_size / 4;
      df->insns = xrealloc (df->insns, 
			    new_size *sizeof (struct df_insn_info *));
      memset (df->insns + df->insns_size, 0,
	      (new_size - df->insns_size) *sizeof (struct df_insn_info *));
      df->insns_size = new_size;
    }
}




/*----------------------------------------------------------------------------
   PUBLIC INTERFACES FOR SMALL GRAIN CHANGES TO SCANNING.
----------------------------------------------------------------------------*/

/* Rescan some BLOCKS or all the blocks defined by the last call to
   df_set_blocks if BLOCKS is NULL);  */

void
df_rescan_blocks (struct df *df, bitmap blocks)
{
  bitmap local_blocks_to_scan = BITMAP_ALLOC (NULL);

  struct dataflow *dflow = df->problems_by_index[DF_SCAN];
  basic_block bb;

  df->def_info.refs_organized = false;
  df->use_info.refs_organized = false;

  if (blocks)
    {
      int i;
      unsigned int bb_index;
      bitmap_iterator bi;
      bool cleared_bits = false;

      /* Need to assure that there are space in all of the tables.  */
      unsigned int insn_num = get_max_uid () + 1;
      insn_num += insn_num / 4;

      df_grow_reg_info (dflow, &df->def_info);
      df_grow_ref_info (&df->def_info, insn_num);
      
      df_grow_reg_info (dflow, &df->use_info);
      df_grow_ref_info (&df->use_info, insn_num *2);
      
      df_grow_insn_info (df);
      df_grow_bb_info (dflow);

      bitmap_copy (local_blocks_to_scan, blocks);

      EXECUTE_IF_SET_IN_BITMAP (blocks, 0, bb_index, bi)
	{
	  basic_block bb = BASIC_BLOCK (bb_index);
	  if (!bb)
	    {
	      bitmap_clear_bit (local_blocks_to_scan, bb_index);
	      cleared_bits = true;
	    }
	}

      if (cleared_bits)
	bitmap_copy (blocks, local_blocks_to_scan);

      df->def_info.add_refs_inline = true;
      df->use_info.add_refs_inline = true;

      for (i = df->num_problems_defined; i; i--)
	{
	  bitmap blocks_to_reset = NULL;
	  if (dflow->problem->reset_fun)
	    {
	      if (!blocks_to_reset)
		{
		  blocks_to_reset = BITMAP_ALLOC (NULL);
		  bitmap_copy (blocks_to_reset, local_blocks_to_scan);
		  if (df->blocks_to_scan)
		    bitmap_ior_into (blocks_to_reset, df->blocks_to_scan);
		}
	      dflow->problem->reset_fun (dflow, blocks_to_reset);
	    }
	  if (blocks_to_reset)
	    BITMAP_FREE (blocks_to_reset);
	}

      df_refs_delete (dflow, local_blocks_to_scan);

      /* This may be a mistake, but if an explicit blocks is passed in
         and the set of blocks to analyze has been explicitly set, add
         the extra blocks to blocks_to_analyze.  The alternative is to
         put an assert here.  We do not want this to just go by
         silently or else we may get storage leaks.  */
      if (df->blocks_to_analyze)
	bitmap_ior_into (df->blocks_to_analyze, blocks);
    }
  else
    {
      /* If we are going to do everything, just reallocate everything.
	 Most stuff is allocated in pools so this is faster than
	 walking it.  */
      if (df->blocks_to_analyze)
	bitmap_copy (local_blocks_to_scan, df->blocks_to_analyze);
      else
	FOR_ALL_BB (bb) 
	  {
	    bitmap_set_bit (local_blocks_to_scan, bb->index);
	  }
      df_scan_alloc (dflow, local_blocks_to_scan, NULL);

      df->def_info.add_refs_inline = false;
      df->use_info.add_refs_inline = false;
    }

  df_refs_record (dflow, local_blocks_to_scan);
#if 0
  bitmap_print (stderr, local_blocks_to_scan, "scanning: ", "\n");
#endif
      
  if (!df->blocks_to_scan)
    df->blocks_to_scan = BITMAP_ALLOC (NULL);

  bitmap_ior_into (df->blocks_to_scan, local_blocks_to_scan); 
  BITMAP_FREE (local_blocks_to_scan);
}


/* Create a new ref of type DF_REF_TYPE for register REG at address
   LOC within INSN of BB.  */

struct df_ref *
df_ref_create (struct df *df, rtx reg, rtx *loc, rtx insn, 
	       basic_block bb,
	       enum df_ref_type ref_type, 
	       enum df_ref_flags ref_flags)
{
  struct dataflow *dflow = df->problems_by_index[DF_SCAN];
  struct df_scan_bb_info *bb_info;
  
  df_grow_reg_info (dflow, &df->use_info);
  df_grow_reg_info (dflow, &df->def_info);
  df_grow_bb_info (dflow);
  
  /* Make sure there is the bb_info for this block.  */
  bb_info = df_scan_get_bb_info (dflow, bb->index);
  if (!bb_info)
    {
      bb_info = (struct df_scan_bb_info *) pool_alloc (dflow->block_pool);
      df_scan_set_bb_info (dflow, bb->index, bb_info);
      bb_info->artificial_defs = NULL;
      bb_info->artificial_uses = NULL;
    }

  if (ref_type == DF_REF_REG_DEF)
    df->def_info.add_refs_inline = true;
  else
    df->use_info.add_refs_inline = true;
  
  return df_ref_create_structure (dflow, reg, loc, bb, insn, ref_type, ref_flags);
}



/*----------------------------------------------------------------------------
   UTILITIES TO CREATE AND DESTROY REFS AND CHAINS.
----------------------------------------------------------------------------*/


/* Get the artificial uses for a basic block.  */

struct df_ref *
df_get_artificial_defs (struct df *df, unsigned int bb_index)
{
  struct dataflow *dflow = df->problems_by_index[DF_SCAN];
  return df_scan_get_bb_info (dflow, bb_index)->artificial_defs;
}


/* Get the artificial uses for a basic block.  */

struct df_ref *
df_get_artificial_uses (struct df *df, unsigned int bb_index)
{
  struct dataflow *dflow = df->problems_by_index[DF_SCAN];
  return df_scan_get_bb_info (dflow, bb_index)->artificial_uses;
}


/* Link REF at the front of reg_use or reg_def chain for REGNO.  */

void
df_reg_chain_create (struct df_reg_info *reg_info, 
		     struct df_ref *ref) 
{
  struct df_ref *head = reg_info->reg_chain;
  reg_info->reg_chain = ref;

  DF_REF_NEXT_REG (ref) = head;

  /* We cannot actually link to the head of the chain.  */
  DF_REF_PREV_REG (ref) = NULL;

  if (head)
    DF_REF_PREV_REG (head) = ref;
}


/* Remove REF from the CHAIN.  Return the head of the chain.  This
   will be CHAIN unless the REF was at the beginning of the chain.  */

static struct df_ref *
df_ref_unlink (struct df_ref *chain, struct df_ref *ref)
{
  struct df_ref *orig_chain = chain;
  struct df_ref *prev = NULL;
  while (chain)
    {
      if (chain == ref)
	{
	  if (prev)
	    {
	      prev->next_ref = ref->next_ref;
	      ref->next_ref = NULL;
	      return orig_chain;
	    }
	  else
	    {
	      chain = ref->next_ref;
	      ref->next_ref = NULL;
	      return chain;
	    }
	}

      prev = chain;
      chain = chain->next_ref;
    }

  /* Someone passed in a ref that was not in the chain.  */
  gcc_unreachable ();
  return NULL;
}


/* Unlink and delete REF at the reg_use or reg_def chain.  Also delete
   the def-use or use-def chain if it exists.  Returns the next ref in
   uses or defs chain.  */

struct df_ref *
df_reg_chain_unlink (struct dataflow *dflow, struct df_ref *ref) 
{
  struct df *df = dflow->df;
  struct df_ref *next = DF_REF_NEXT_REG (ref);  
  struct df_ref *prev = DF_REF_PREV_REG (ref);
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;
  struct df_reg_info *reg_info;
  struct df_ref *next_ref = ref->next_ref;
  unsigned int id = DF_REF_ID (ref);

  if (DF_REF_TYPE (ref) == DF_REF_REG_DEF)
    {
      reg_info = DF_REG_DEF_GET (df, DF_REF_REGNO (ref));
      df->def_info.bitmap_size--;
      if (df->def_info.refs && (id < df->def_info.refs_size))
	DF_DEFS_SET (df, id, NULL);
    }
  else 
    {
      reg_info = DF_REG_USE_GET (df, DF_REF_REGNO (ref));
      df->use_info.bitmap_size--;
      if (df->use_info.refs && (id < df->use_info.refs_size))
	DF_USES_SET (df, id, NULL);
    }
  
  /* Delete any def-use or use-def chains that start here.  */
  if (DF_REF_CHAIN (ref))
    df_chain_unlink (df->problems_by_index[DF_CHAIN], ref, NULL);

  reg_info->n_refs--;

  /* Unlink from the reg chain.  If there is no prev, this is the
     first of the list.  If not, just join the next and prev.  */
  if (prev)
    {
      DF_REF_NEXT_REG (prev) = next;
      if (next)
	DF_REF_PREV_REG (next) = prev;
    }
  else
    {
      reg_info->reg_chain = next;
      if (next)
	DF_REF_PREV_REG (next) = NULL;
    }

  pool_free (problem_data->ref_pool, ref);
  return next_ref;
}


/* Unlink REF from all def-use/use-def chains, etc.  */

void
df_ref_remove (struct df *df, struct df_ref *ref)
{
  struct dataflow *dflow = df->problems_by_index[DF_SCAN];
  if (DF_REF_REG_DEF_P (ref))
    {
      if (DF_REF_FLAGS (ref) & DF_REF_ARTIFICIAL)
	{
	  struct df_scan_bb_info *bb_info 
	    = df_scan_get_bb_info (dflow, DF_REF_BB (ref)->index);
	  bb_info->artificial_defs 
	    = df_ref_unlink (bb_info->artificial_defs, ref);
	}
      else
	DF_INSN_UID_DEFS (df, DF_REF_INSN_UID (ref))
	  = df_ref_unlink (DF_INSN_UID_DEFS (df, DF_REF_INSN_UID (ref)), ref);

      if (df->def_info.add_refs_inline)
	DF_DEFS_SET (df, DF_REF_ID (ref), NULL);
    }
  else
    {
      if (DF_REF_FLAGS (ref) & DF_REF_ARTIFICIAL)
	{
	  struct df_scan_bb_info *bb_info 
	    = df_scan_get_bb_info (dflow, DF_REF_BB (ref)->index);
	  bb_info->artificial_uses 
	    = df_ref_unlink (bb_info->artificial_uses, ref);
	}
      else
	DF_INSN_UID_USES (df, DF_REF_INSN_UID (ref))
	  = df_ref_unlink (DF_INSN_UID_USES (df, DF_REF_INSN_UID (ref)), ref);
      
      if (df->use_info.add_refs_inline)
	DF_USES_SET (df, DF_REF_ID (ref), NULL);
    }

  df_reg_chain_unlink (dflow, ref);
}


/* Create the insn record for INSN.  If there was one there, zero it out.  */

static struct df_insn_info *
df_insn_create_insn_record (struct dataflow *dflow, rtx insn)
{
  struct df *df = dflow->df;
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;

  struct df_insn_info *insn_rec = DF_INSN_GET (df, insn);
  if (!insn_rec)
    {
      insn_rec = pool_alloc (problem_data->insn_pool);
      DF_INSN_SET (df, insn, insn_rec);
    }
  memset (insn_rec, 0, sizeof (struct df_insn_info));

  return insn_rec;
}


/* Delete all of the refs information from INSN.  */

void 
df_insn_refs_delete (struct dataflow *dflow, rtx insn)
{
  struct df *df = dflow->df;
  unsigned int uid = INSN_UID (insn);
  struct df_insn_info *insn_info = NULL;
  struct df_ref *ref;
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;

  if (uid < df->insns_size)
    insn_info = DF_INSN_UID_GET (df, uid);

  if (insn_info)
    {
      struct df_mw_hardreg *hardregs = insn_info->mw_hardregs;
      
      while (hardregs)
	{
	  struct df_mw_hardreg *next_hr = hardregs->next;
	  struct df_link *link = hardregs->regs;
	  while (link)
	    {
	      struct df_link *next_l = link->next;
	      pool_free (problem_data->mw_link_pool, link);
	      link = next_l;
	    }
	  
	  pool_free (problem_data->mw_reg_pool, hardregs);
	  hardregs = next_hr;
	}

      ref = insn_info->defs;
      while (ref) 
	ref = df_reg_chain_unlink (dflow, ref);
      
      ref = insn_info->uses;
      while (ref) 
	ref = df_reg_chain_unlink (dflow, ref);

      pool_free (problem_data->insn_pool, insn_info);
      DF_INSN_SET (df, insn, NULL);
    }
}


/* Delete all of the refs information from basic_block with BB_INDEX.  */

void
df_bb_refs_delete (struct dataflow *dflow, int bb_index)
{
  struct df_ref *def;
  struct df_ref *use;

  struct df_scan_bb_info *bb_info 
    = df_scan_get_bb_info (dflow, bb_index);
  rtx insn;
  basic_block bb = BASIC_BLOCK (bb_index);
  FOR_BB_INSNS (bb, insn)
    {
      if (INSN_P (insn))
	{
	  /* Record defs within INSN.  */
	  df_insn_refs_delete (dflow, insn);
	}
    }
  
  /* Get rid of any artificial uses or defs.  */
  if (bb_info)
    {
      def = bb_info->artificial_defs;
      while (def)
	def = df_reg_chain_unlink (dflow, def);
      bb_info->artificial_defs = NULL;
      use = bb_info->artificial_uses;
      while (use)
	use = df_reg_chain_unlink (dflow, use);
      bb_info->artificial_uses = NULL;
    }
}


/* Delete all of the refs information from BLOCKS.  */

void 
df_refs_delete (struct dataflow *dflow, bitmap blocks)
{
  bitmap_iterator bi;
  unsigned int bb_index;

  EXECUTE_IF_SET_IN_BITMAP (blocks, 0, bb_index, bi)
    {
      df_bb_refs_delete (dflow, bb_index);
    }
}


/* Take build ref table for either the uses or defs from the reg-use
   or reg-def chains.  */ 

void 
df_reorganize_refs (struct df_ref_info *ref_info)
{
  unsigned int m = ref_info->regs_inited;
  unsigned int regno;
  unsigned int offset = 0;
  unsigned int size = 0;

  if (ref_info->refs_organized)
    return;

  if (ref_info->refs_size < ref_info->bitmap_size)
    {  
      int new_size = ref_info->bitmap_size + ref_info->bitmap_size / 4;
      df_grow_ref_info (ref_info, new_size);
    }

  for (regno = 0; regno < m; regno++)
    {
      struct df_reg_info *reg_info = ref_info->regs[regno];
      int count = 0;
      if (reg_info)
	{
	  struct df_ref *ref = reg_info->reg_chain;
	  reg_info->begin = offset;
	  while (ref) 
	    {
	      ref_info->refs[offset] = ref;
	      DF_REF_ID (ref) = offset++;
	      ref = DF_REF_NEXT_REG (ref);
	      count++;
	      size++;
	    }
	  reg_info->n_refs = count;
	}
    }

  /* The bitmap size is not decremented when refs are deleted.  So
     reset it now that we have squished out all of the empty
     slots.  */
  ref_info->bitmap_size = size;
  ref_info->refs_organized = true;
  ref_info->add_refs_inline = true;
}


/*----------------------------------------------------------------------------
   Hard core instruction scanning code.  No external interfaces here,
   just a lot of routines that look inside insns.
----------------------------------------------------------------------------*/

/* Create a ref and add it to the reg-def or reg-use chains.  */

static struct df_ref *
df_ref_create_structure (struct dataflow *dflow, rtx reg, rtx *loc,
			 basic_block bb, rtx insn, 
			 enum df_ref_type ref_type, 
			 enum df_ref_flags ref_flags)
{
  struct df_ref *this_ref;
  struct df *df = dflow->df;
  int regno = REGNO (GET_CODE (reg) == SUBREG ? SUBREG_REG (reg) : reg);
  struct df_scan_problem_data *problem_data
    = (struct df_scan_problem_data *) dflow->problem_data;

  this_ref = pool_alloc (problem_data->ref_pool);
  DF_REF_REG (this_ref) = reg;
  DF_REF_REGNO (this_ref) =  regno;
  DF_REF_LOC (this_ref) = loc;
  DF_REF_INSN (this_ref) = insn;
  DF_REF_CHAIN (this_ref) = NULL;
  DF_REF_TYPE (this_ref) = ref_type;
  DF_REF_FLAGS (this_ref) = ref_flags;
  DF_REF_DATA (this_ref) = NULL;
  DF_REF_BB (this_ref) = bb;

  /* Link the ref into the reg_def and reg_use chains and keep a count
     of the instances.  */
  switch (ref_type)
    {
    case DF_REF_REG_DEF:
      {
	struct df_reg_info *reg_info = DF_REG_DEF_GET (df, regno);
	reg_info->n_refs++;
	
	/* Add the ref to the reg_def chain.  */
	df_reg_chain_create (reg_info, this_ref);
	DF_REF_ID (this_ref) = df->def_info.bitmap_size;
	if (df->def_info.add_refs_inline)
	  {
	    if (DF_DEFS_SIZE (df) >= df->def_info.refs_size)
	      {
		int new_size = df->def_info.bitmap_size 
		  + df->def_info.bitmap_size / 4;
		df_grow_ref_info (&df->def_info, new_size);
	      }
	    /* Add the ref to the big array of defs.  */
	    DF_DEFS_SET (df, df->def_info.bitmap_size, this_ref);
	    df->def_info.refs_organized = false;
	  }
	
	df->def_info.bitmap_size++;
	
	if (DF_REF_FLAGS (this_ref) & DF_REF_ARTIFICIAL)
	  {
	    struct df_scan_bb_info *bb_info 
	      = df_scan_get_bb_info (dflow, bb->index);
	    this_ref->next_ref = bb_info->artificial_defs;
	    bb_info->artificial_defs = this_ref;
	  }
	else
	  {
	    this_ref->next_ref = DF_INSN_GET (df, insn)->defs;
	    DF_INSN_GET (df, insn)->defs = this_ref;
	  }
      }
      break;

    case DF_REF_REG_MEM_LOAD:
    case DF_REF_REG_MEM_STORE:
    case DF_REF_REG_USE:
      {
	struct df_reg_info *reg_info = DF_REG_USE_GET (df, regno);
	reg_info->n_refs++;
	
	/* Add the ref to the reg_use chain.  */
	df_reg_chain_create (reg_info, this_ref);
	DF_REF_ID (this_ref) = df->use_info.bitmap_size;
	if (df->use_info.add_refs_inline)
	  {
	    if (DF_USES_SIZE (df) >= df->use_info.refs_size)
	      {
		int new_size = df->use_info.bitmap_size 
		  + df->use_info.bitmap_size / 4;
		df_grow_ref_info (&df->use_info, new_size);
	      }
	    /* Add the ref to the big array of defs.  */
	    DF_USES_SET (df, df->use_info.bitmap_size, this_ref);
	    df->use_info.refs_organized = false;
	  }
	
	df->use_info.bitmap_size++;
	if (DF_REF_FLAGS (this_ref) & DF_REF_ARTIFICIAL)
	  {
	    struct df_scan_bb_info *bb_info 
	      = df_scan_get_bb_info (dflow, bb->index);
	    this_ref->next_ref = bb_info->artificial_uses;
	    bb_info->artificial_uses = this_ref;
	  }
	else
	  {
	    this_ref->next_ref = DF_INSN_GET (df, insn)->uses;
	    DF_INSN_GET (df, insn)->uses = this_ref;
	  }
      }
      break;

    default:
      gcc_unreachable ();

    }
  return this_ref;
}


/* Create new references of type DF_REF_TYPE for each part of register REG
   at address LOC within INSN of BB.  */

static void
df_ref_record (struct dataflow *dflow, rtx reg, rtx *loc, 
	       basic_block bb, rtx insn, 
	       enum df_ref_type ref_type, 
	       enum df_ref_flags ref_flags, 
	       bool record_live)
{
  struct df *df = dflow->df;
  rtx oldreg = reg;
  unsigned int regno;

  gcc_assert (REG_P (reg) || GET_CODE (reg) == SUBREG);

  /* For the reg allocator we are interested in some SUBREG rtx's, but not
     all.  Notably only those representing a word extraction from a multi-word
     reg.  As written in the docu those should have the form
     (subreg:SI (reg:M A) N), with size(SImode) > size(Mmode).
     XXX Is that true?  We could also use the global word_mode variable.  */
  if ((dflow->flags & DF_SUBREGS) == 0
      && GET_CODE (reg) == SUBREG
      && (GET_MODE_SIZE (GET_MODE (reg)) < GET_MODE_SIZE (word_mode)
	  || GET_MODE_SIZE (GET_MODE (reg))
	       >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (reg)))))
    {
      loc = &SUBREG_REG (reg);
      reg = *loc;
      ref_flags |= DF_REF_STRIPPED;
    }

  regno = REGNO (GET_CODE (reg) == SUBREG ? SUBREG_REG (reg) : reg);
  if (regno < FIRST_PSEUDO_REGISTER)
    {
      unsigned int i;
      unsigned int endregno;
      struct df_mw_hardreg *hardreg = NULL;
      struct df_scan_problem_data *problem_data
	= (struct df_scan_problem_data *) dflow->problem_data;

      if (!(dflow->flags & DF_HARD_REGS))
	return;

      /* GET_MODE (reg) is correct here.  We do not want to go into a SUBREG
         for the mode, because we only want to add references to regs, which
	 are really referenced.  E.g., a (subreg:SI (reg:DI 0) 0) does _not_
	 reference the whole reg 0 in DI mode (which would also include
	 reg 1, at least, if 0 and 1 are SImode registers).  */
      endregno = hard_regno_nregs[regno][GET_MODE (reg)];
      if (GET_CODE (reg) == SUBREG)
        regno += subreg_regno_offset (regno, GET_MODE (SUBREG_REG (reg)),
				      SUBREG_BYTE (reg), GET_MODE (reg));
      endregno += regno;

      /*  If this is a multiword hardreg, we create some extra datastructures that 
	  will enable us to easily build REG_DEAD and REG_UNUSED notes.  */
      if ((endregno != regno + 1) && insn)
	{
	  struct df_insn_info *insn_info = DF_INSN_GET (df, insn);
	  /* Sets to a subreg of a multiword register are partial. 
	     Sets to a non-subreg of a multiword register are not.  */
	  if (GET_CODE (oldreg) == SUBREG)
	    ref_flags |= DF_REF_PARTIAL;
	  ref_flags |= DF_REF_MW_HARDREG;
	  hardreg = pool_alloc (problem_data->mw_reg_pool);
	  hardreg->next = insn_info->mw_hardregs;
	  insn_info->mw_hardregs = hardreg;
	  hardreg->type = ref_type;
	  hardreg->flags = ref_flags;
	  hardreg->mw_reg = reg;
	  hardreg->regs = NULL;

	}

      for (i = regno; i < endregno; i++)
	{
	  struct df_ref *ref;

	  /* Calls are handled at call site because regs_ever_live
	     doesn't include clobbered regs, only used ones.  */
	  if (ref_type == DF_REF_REG_DEF && record_live)
	    regs_ever_live[i] = 1;
	  else if ((ref_type == DF_REF_REG_USE 
		   || ref_type == DF_REF_REG_MEM_STORE
		   || ref_type == DF_REF_REG_MEM_LOAD)
		   && ((ref_flags & DF_REF_ARTIFICIAL) == 0))
	    {
	      /* Set regs_ever_live on uses of non-eliminable frame
		 pointers and arg pointers.  */
	      if (!(TEST_HARD_REG_BIT (elim_reg_set, regno)
		     && (regno == FRAME_POINTER_REGNUM 
			 || regno == ARG_POINTER_REGNUM)))
		regs_ever_live[i] = 1;
	    }

	  ref = df_ref_create_structure (dflow, regno_reg_rtx[i], loc, 
					 bb, insn, ref_type, ref_flags);
	  if (hardreg)
	    {
	      struct df_link *link = pool_alloc (problem_data->mw_link_pool);

	      link->next = hardreg->regs;
	      link->ref = ref;
	      hardreg->regs = link;
	    }
	}
    }
  else
    {
      df_ref_create_structure (dflow, reg, loc, 
			       bb, insn, ref_type, ref_flags);
    }
}


/* A set to a non-paradoxical SUBREG for which the number of word_mode units
   covered by the outer mode is smaller than that covered by the inner mode,
   is a read-modify-write operation.
   This function returns true iff the SUBREG X is such a SUBREG.  */

bool
df_read_modify_subreg_p (rtx x)
{
  unsigned int isize, osize;
  if (GET_CODE (x) != SUBREG)
    return false;
  isize = GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)));
  osize = GET_MODE_SIZE (GET_MODE (x));
  return (isize > osize && isize > UNITS_PER_WORD);
}


/* Process all the registers defined in the rtx, X.
   Autoincrement/decrement definitions will be picked up by
   df_uses_record.  */

static void
df_def_record_1 (struct dataflow *dflow, rtx x, 
		 basic_block bb, rtx insn, 
		 enum df_ref_flags flags, bool record_live)
{
  rtx *loc;
  rtx dst;
  bool dst_in_strict_lowpart = false;

 /* We may recursively call ourselves on EXPR_LIST when dealing with PARALLEL
     construct.  */
  if (GET_CODE (x) == EXPR_LIST || GET_CODE (x) == CLOBBER)
    loc = &XEXP (x, 0);
  else
    loc = &SET_DEST (x);
  dst = *loc;

  /* It is legal to have a set destination be a parallel. */
  if (GET_CODE (dst) == PARALLEL)
    {
      int i;

      for (i = XVECLEN (dst, 0) - 1; i >= 0; i--)
	{
	  rtx temp = XVECEXP (dst, 0, i);
	  if (GET_CODE (temp) == EXPR_LIST || GET_CODE (temp) == CLOBBER
	      || GET_CODE (temp) == SET)
	    df_def_record_1 (dflow, temp, bb, insn, 
			     GET_CODE (temp) == CLOBBER 
			     ? flags | DF_REF_MUST_CLOBBER : flags, 
			     record_live);
	}
      return;
    }

  /* Maybe, we should flag the use of STRICT_LOW_PART somehow.  It might
     be handy for the reg allocator.  */
  while (GET_CODE (dst) == STRICT_LOW_PART
	 || GET_CODE (dst) == ZERO_EXTRACT
	 || df_read_modify_subreg_p (dst))
    {
#if 0
      /* Strict low part always contains SUBREG, but we do not want to make
	 it appear outside, as whole register is always considered.  */
      if (GET_CODE (dst) == STRICT_LOW_PART)
	{
	  loc = &XEXP (dst, 0);
	  dst = *loc;
	}
#endif
      loc = &XEXP (dst, 0);
      if (GET_CODE (dst) == STRICT_LOW_PART)
	dst_in_strict_lowpart = true;
      dst = *loc;
      flags |= DF_REF_READ_WRITE;

    }

  /* Sets to a subreg of a single word register are partial sets if
     they are wrapped in a strict lowpart, and not partial otherwise.
  */
  if (GET_CODE (dst) == SUBREG && REG_P (SUBREG_REG (dst))
      && dst_in_strict_lowpart)
    flags |= DF_REF_PARTIAL;
    
  if (REG_P (dst)
      || (GET_CODE (dst) == SUBREG && REG_P (SUBREG_REG (dst))))
    df_ref_record (dflow, dst, loc, bb, insn, 
		   DF_REF_REG_DEF, flags, record_live);
}


/* Process all the registers defined in the pattern rtx, X.  */

static void
df_defs_record (struct dataflow *dflow, rtx x, basic_block bb, rtx insn)
{
  RTX_CODE code = GET_CODE (x);

  if (code == SET || code == CLOBBER)
    {
      /* Mark the single def within the pattern.  */
      df_def_record_1 (dflow, x, bb, insn, 
		       code == CLOBBER ? DF_REF_MUST_CLOBBER : 0, true);
    }
  else if (code == COND_EXEC)
    {
      df_defs_record  (dflow, COND_EXEC_CODE (x), bb, insn);
    }
  else if (code == PARALLEL)
    {
      int i;

      /* Mark the multiple defs within the pattern.  */
      for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
	 df_defs_record (dflow, XVECEXP (x, 0, i), bb, insn);
    }
}


/* Process all the registers used in the rtx at address LOC.  */

static void
df_uses_record (struct dataflow *dflow, rtx *loc, enum df_ref_type ref_type,
		basic_block bb, rtx insn, enum df_ref_flags flags)
{
  RTX_CODE code;
  rtx x;
 retry:
  x = *loc;
  if (!x)
    return;
  code = GET_CODE (x);
  switch (code)
    {
    case LABEL_REF:
    case SYMBOL_REF:
    case CONST_INT:
    case CONST:
    case CONST_DOUBLE:
    case CONST_VECTOR:
    case PC:
    case CC0:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
      return;

    case CLOBBER:
      /* If we are clobbering a MEM, mark any registers inside the address
	 as being used.  */
      if (MEM_P (XEXP (x, 0)))
	df_uses_record (dflow, &XEXP (XEXP (x, 0), 0),
			DF_REF_REG_MEM_STORE, bb, insn, flags);

      /* If we're clobbering a REG then we have a def so ignore.  */
      return;

    case MEM:
      df_uses_record (dflow, &XEXP (x, 0), DF_REF_REG_MEM_LOAD, bb, insn,
		      flags & DF_REF_IN_NOTE);
      return;

    case SUBREG:
      /* While we're here, optimize this case.  */
      flags |= DF_REF_PARTIAL;
      /* In case the SUBREG is not of a REG, do not optimize.  */
      if (!REG_P (SUBREG_REG (x)))
	{
	  loc = &SUBREG_REG (x);
	  df_uses_record (dflow, loc, ref_type, bb, insn, flags);
	  return;
	}
      /* ... Fall through ...  */

    case REG:
      df_ref_record (dflow, x, loc, bb, insn, ref_type, flags, true);
      return;

    case SET:
      {
	rtx dst = SET_DEST (x);
	gcc_assert (!(flags & DF_REF_IN_NOTE));
	df_uses_record (dflow, &SET_SRC (x), DF_REF_REG_USE, bb, insn, flags);

	switch (GET_CODE (dst))
	  {
	    case SUBREG:
	      if (df_read_modify_subreg_p (dst))
		{
		  df_uses_record (dflow, &SUBREG_REG (dst), 
				  DF_REF_REG_USE, bb,
				  insn, flags | DF_REF_READ_WRITE);
		  break;
		}
	      /* Fall through.  */
	    case REG:
	    case PARALLEL:
	    case SCRATCH:
	    case PC:
	    case CC0:
		break;
	    case MEM:
	      df_uses_record (dflow, &XEXP (dst, 0),
			      DF_REF_REG_MEM_STORE,
			      bb, insn, flags);
	      break;
	    case STRICT_LOW_PART:
	      {
		rtx *temp = &XEXP (dst, 0);
		/* A strict_low_part uses the whole REG and not just the
		 SUBREG.  */
		dst = XEXP (dst, 0);
		df_uses_record (dflow, 
				(GET_CODE (dst) == SUBREG) 
				? &SUBREG_REG (dst) : temp, 
				DF_REF_REG_USE, bb,
				insn, DF_REF_READ_WRITE);
	      }
	      break;
	    case ZERO_EXTRACT:
	    case SIGN_EXTRACT:
	      df_uses_record (dflow, &XEXP (dst, 0), 
			      DF_REF_REG_USE, bb, insn,
			      DF_REF_READ_WRITE);
	      df_uses_record (dflow, &XEXP (dst, 1), 
			      DF_REF_REG_USE, bb, insn, flags);
	      df_uses_record (dflow, &XEXP (dst, 2), 
			      DF_REF_REG_USE, bb, insn, flags);
	      dst = XEXP (dst, 0);
	      break;
	    default:
	      gcc_unreachable ();
	  }
	return;
      }

    case RETURN:
      break;

    case ASM_OPERANDS:
    case UNSPEC_VOLATILE:
    case TRAP_IF:
    case ASM_INPUT:
      {
	/* Traditional and volatile asm instructions must be
	   considered to use and clobber all hard registers, all
	   pseudo-registers and all of memory.  So must TRAP_IF and
	   UNSPEC_VOLATILE operations.

	   Consider for instance a volatile asm that changes the fpu
	   rounding mode.  An insn should not be moved across this
	   even if it only uses pseudo-regs because it might give an
	   incorrectly rounded result.

	   However, flow.c's liveness computation did *not* do this,
	   giving the reasoning as " ?!? Unfortunately, marking all
	   hard registers as live causes massive problems for the
	   register allocator and marking all pseudos as live creates
	   mountains of uninitialized variable warnings."

	   In order to maintain the status quo with regard to liveness
	   and uses, we do what flow.c did and just mark any regs we
	   can find in ASM_OPERANDS as used.  Later on, when liveness
	   is computed, asm insns are scanned and regs_asm_clobbered
	   is filled out.  

	   For all ASM_OPERANDS, we must traverse the vector of input
	   operands.  We can not just fall through here since then we
	   would be confused by the ASM_INPUT rtx inside ASM_OPERANDS,
	   which do not indicate traditional asms unlike their normal
	   usage.  */
	if (code == ASM_OPERANDS)
	  {
	    int j;

	    for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
	      df_uses_record (dflow, &ASM_OPERANDS_INPUT (x, j),
			      DF_REF_REG_USE, bb, insn, flags);
	    return;
	  }
	break;
      }

    case PRE_DEC:
    case POST_DEC:
    case PRE_INC:
    case POST_INC:
    case PRE_MODIFY:
    case POST_MODIFY:
      /* Catch the def of the register being modified.  */
      flags |= DF_REF_READ_WRITE;
      df_ref_record (dflow, XEXP (x, 0), &XEXP (x, 0), bb, insn, 
		     DF_REF_REG_DEF, flags, true);

      /* ... Fall through to handle uses ...  */

    default:
      break;
    }

  /* Recursively scan the operands of this expression.  */
  {
    const char *fmt = GET_RTX_FORMAT (code);
    int i;

    for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
      {
	if (fmt[i] == 'e')
	  {
	    /* Tail recursive case: save a function call level.  */
	    if (i == 0)
	      {
		loc = &XEXP (x, 0);
		goto retry;
	      }
	    df_uses_record (dflow, &XEXP (x, i), ref_type, bb, insn, flags);
	  }
	else if (fmt[i] == 'E')
	  {
	    int j;
	    for (j = 0; j < XVECLEN (x, i); j++)
	      df_uses_record (dflow, &XVECEXP (x, i, j), ref_type,
			      bb, insn, flags);
	  }
      }
  }
}

/* Return true if *LOC contains an asm.  */

static int
df_insn_contains_asm_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
{
  if ( !*loc)
    return 0;
  if (GET_CODE (*loc) == ASM_OPERANDS)
    return 1;
  return 0;
}


/* Return true if INSN contains an ASM.  */

static int
df_insn_contains_asm (rtx insn)
{
  return for_each_rtx (&insn, df_insn_contains_asm_1, NULL);
}



/* Record all the refs for DF within INSN of basic block BB.  */

static void
df_insn_refs_record (struct dataflow *dflow, basic_block bb, rtx insn)
{
  struct df *df = dflow->df;
  int i;

  if (INSN_P (insn))
    {
      rtx note;

      if (df_insn_contains_asm (insn))
	DF_INSN_CONTAINS_ASM (df, insn) = true;
      
      /* Record register defs.  */
      df_defs_record (dflow, PATTERN (insn), bb, insn);

      if (dflow->flags & DF_EQUIV_NOTES)
	for (note = REG_NOTES (insn); note;
	     note = XEXP (note, 1))
	  {
	    switch (REG_NOTE_KIND (note))
	      {
	      case REG_EQUIV:
	      case REG_EQUAL:
		df_uses_record (dflow, &XEXP (note, 0), DF_REF_REG_USE,
				bb, insn, DF_REF_IN_NOTE);
	      default:
		break;
	      }
	  }

      if (CALL_P (insn))
	{
	  rtx note;

	  /* Record the registers used to pass arguments, and explicitly
	     noted as clobbered.  */
	  for (note = CALL_INSN_FUNCTION_USAGE (insn); note;
	       note = XEXP (note, 1))
	    {
	      if (GET_CODE (XEXP (note, 0)) == USE)
		df_uses_record (dflow, &XEXP (XEXP (note, 0), 0), 
				DF_REF_REG_USE,
				bb, insn, 0);
              else if (GET_CODE (XEXP (note, 0)) == CLOBBER)
		{
		  df_defs_record (dflow, XEXP (note, 0), bb, insn);
		  if (REG_P (XEXP (XEXP (note, 0), 0)))
		    {
		      rtx reg = XEXP (XEXP (note, 0), 0);
		      int regno_last;
		      int regno_first;
		      int i;
		
		      regno_last = regno_first = REGNO (reg);
		      if (regno_first < FIRST_PSEUDO_REGISTER)
			regno_last 
			  += hard_regno_nregs[regno_first][GET_MODE (reg)] - 1;
		      for (i = regno_first; i <= regno_last; i++)
			regs_ever_live[i] = 1;
		    }
		}
	    }

	  /* The stack ptr is used (honorarily) by a CALL insn.  */
	  df_uses_record (dflow, &regno_reg_rtx[STACK_POINTER_REGNUM],
			  DF_REF_REG_USE, bb, insn, 
			  0);

	  if (dflow->flags & DF_HARD_REGS)
	    {
	      bitmap_iterator bi;
	      unsigned int ui;
	      /* Calls may also reference any of the global registers,
		 so they are recorded as used.  */
	      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
		if (global_regs[i])
		  df_uses_record (dflow, &regno_reg_rtx[i],
				  DF_REF_REG_USE, bb, insn, 
				  0);
	      EXECUTE_IF_SET_IN_BITMAP (df_invalidated_by_call, 0, ui, bi)
	        df_ref_record (dflow, regno_reg_rtx[ui], &regno_reg_rtx[ui], bb, 
			       insn, DF_REF_REG_DEF, DF_REF_MAY_CLOBBER, false);
	    }
	}

      /* Record the register uses.  */
      df_uses_record (dflow, &PATTERN (insn),
		      DF_REF_REG_USE, bb, insn, 0);

    }
}

static bool
df_has_eh_preds (basic_block bb)
{
  edge e;
  edge_iterator ei;

  FOR_EACH_EDGE (e, ei, bb->preds)
    {
      if (e->flags & EDGE_EH)
	return true;
    }
  return false;
}

/* Record all the refs within the basic block BB.  */

static void
df_bb_refs_record (struct dataflow *dflow, basic_block bb)
{
  struct df *df = dflow->df;
  rtx insn;
  int luid = 0;
  struct df_scan_bb_info *bb_info = df_scan_get_bb_info (dflow, bb->index);
  bitmap artificial_uses_at_bottom = NULL;

  if (dflow->flags & DF_HARD_REGS)
    artificial_uses_at_bottom = BITMAP_ALLOC (NULL);

  /* Need to make sure that there is a record in the basic block info. */  
  if (!bb_info)
    {
      bb_info = (struct df_scan_bb_info *) pool_alloc (dflow->block_pool);
      df_scan_set_bb_info (dflow, bb->index, bb_info);
      bb_info->artificial_defs = NULL;
      bb_info->artificial_uses = NULL;
    }

  /* Scan the block an insn at a time from beginning to end.  */
  FOR_BB_INSNS (bb, insn)
    {
      df_insn_create_insn_record (dflow, insn);
      if (INSN_P (insn))
	{
	  /* Record defs within INSN.  */
	  DF_INSN_LUID (df, insn) = luid++;
	  df_insn_refs_record (dflow, bb, insn);
	}
      DF_INSN_LUID (df, insn) = luid;
    }

#ifdef EH_RETURN_DATA_REGNO
  if ((dflow->flags & DF_HARD_REGS)
      && df_has_eh_preds (bb))
    {
      unsigned int i;
      /* Mark the registers that will contain data for the handler.  */
      for (i = 0; ; ++i)
	{
	  unsigned regno = EH_RETURN_DATA_REGNO (i);
	  if (regno == INVALID_REGNUM)
	    break;
	  df_ref_record (dflow, regno_reg_rtx[regno], &regno_reg_rtx[regno],
			 bb, NULL,
			 DF_REF_REG_DEF, DF_REF_ARTIFICIAL | DF_REF_AT_TOP,
			 false);
	}
    }
#endif


  if ((dflow->flags & DF_HARD_REGS)
      && df_has_eh_preds (bb))
    {
#ifdef EH_USES
      unsigned int i;
      /* This code is putting in a artificial ref for the use at the
	 TOP of the block that receives the exception.  It is too
	 cumbersome to actually put the ref on the edge.  We could
	 either model this at the top of the receiver block or the
	 bottom of the sender block.

         The bottom of the sender block is problematic because not all
         out-edges of the a block are eh-edges.  However, it is true
         that all edges into a block are either eh-edges or none of
         them are eh-edges.  Thus, we can model this at the top of the
         eh-receiver for all of the edges at once. */
      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if (EH_USES (i))
	  df_uses_record (dflow, &regno_reg_rtx[i], 
			  DF_REF_REG_USE, bb, NULL,
			  DF_REF_ARTIFICIAL | DF_REF_AT_TOP);
#endif

      /* The following code (down thru the arg_pointer setting APPEARS
	 to be necessary because there is nothing that actually
	 describes what the exception handling code may actually need
	 to keep alive.  */
      if (reload_completed)
	{
	  if (frame_pointer_needed)
	    {
	      bitmap_set_bit (artificial_uses_at_bottom, FRAME_POINTER_REGNUM);
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
	      bitmap_set_bit (artificial_uses_at_bottom, HARD_FRAME_POINTER_REGNUM);
#endif
	    }
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
	  if (fixed_regs[ARG_POINTER_REGNUM])
	    bitmap_set_bit (artificial_uses_at_bottom, ARG_POINTER_REGNUM);
#endif
	}
    }

  if ((dflow->flags & DF_HARD_REGS) 
      && bb->index >= NUM_FIXED_BLOCKS)
    {
      /* Before reload, there are a few registers that must be forced
	 live everywhere -- which might not already be the case for
	 blocks within infinite loops.  */
      if (!reload_completed)
	{
	  
	  /* Any reference to any pseudo before reload is a potential
	     reference of the frame pointer.  */
	  bitmap_set_bit (artificial_uses_at_bottom, FRAME_POINTER_REGNUM);
	  
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
	  /* Pseudos with argument area equivalences may require
	     reloading via the argument pointer.  */
	  if (fixed_regs[ARG_POINTER_REGNUM])
	    bitmap_set_bit (artificial_uses_at_bottom, ARG_POINTER_REGNUM);
#endif
	  
	  /* Any constant, or pseudo with constant equivalences, may
	     require reloading from memory using the pic register.  */
	  if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
	      && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
	    bitmap_set_bit (artificial_uses_at_bottom, PIC_OFFSET_TABLE_REGNUM);
	}
      /* The all-important stack pointer must always be live.  */
      bitmap_set_bit (artificial_uses_at_bottom, STACK_POINTER_REGNUM);
    }

  if (dflow->flags & DF_HARD_REGS)
    {
      bitmap_iterator bi;
      unsigned int regno;

      EXECUTE_IF_SET_IN_BITMAP (artificial_uses_at_bottom, 0, regno, bi)
	{
	  df_uses_record (dflow, &regno_reg_rtx[regno],
			  DF_REF_REG_USE, bb, NULL, DF_REF_ARTIFICIAL);
	}

      BITMAP_FREE (artificial_uses_at_bottom);
    }
}


/* Record all the refs in the basic blocks specified by BLOCKS.  */

static void
df_refs_record (struct dataflow *dflow, bitmap blocks)
{
  unsigned int bb_index;
  bitmap_iterator bi;

  EXECUTE_IF_SET_IN_BITMAP (blocks, 0, bb_index, bi)
    {
      basic_block bb = BASIC_BLOCK (bb_index);
      df_bb_refs_record (dflow, bb);
    }

  if (bitmap_bit_p (blocks, EXIT_BLOCK))
    df_record_exit_block_uses (dflow);

  if (bitmap_bit_p (blocks, ENTRY_BLOCK))
    df_record_entry_block_defs (dflow);
}


/*----------------------------------------------------------------------------
   Specialized hard register scanning functions.
----------------------------------------------------------------------------*/

/* Mark a register in SET.  Hard registers in large modes get all
   of their component registers set as well.  */

static void
df_mark_reg (rtx reg, void *vset)
{
  bitmap set = (bitmap) vset;
  int regno = REGNO (reg);

  gcc_assert (GET_MODE (reg) != BLKmode);

  bitmap_set_bit (set, regno);
  if (regno < FIRST_PSEUDO_REGISTER)
    {
      int n = hard_regno_nregs[regno][GET_MODE (reg)];
      while (--n > 0)
	bitmap_set_bit  (set, regno + n);
    }
}


/* Record the (conservative) set of hard registers that are defined on
   entry to the function.  */

static void
df_record_entry_block_defs (struct dataflow *dflow)
{
  unsigned int i; 
  bitmap_iterator bi;
  rtx r;
  struct df *df = dflow->df;

  bitmap_clear (df->entry_block_defs);

  if (!(dflow->flags & DF_HARD_REGS))
    return;

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      if (FUNCTION_ARG_REGNO_P (i))
#ifdef INCOMING_REGNO
	bitmap_set_bit (df->entry_block_defs, INCOMING_REGNO (i));
#else
	bitmap_set_bit (df->entry_block_defs, i);
#endif
    }
      
  /* Once the prologue has been generated, all of these registers
     should just show up in the first regular block.  */
  if (HAVE_prologue && epilogue_completed)
    {
      /* Defs for the callee saved registers are inserted so that the
	 pushes have some defining location.  */
      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if ((call_used_regs[i] == 0) && (regs_ever_live[i]))
	  bitmap_set_bit (df->entry_block_defs, i);
    }
  else
    {
      /* The always important stack pointer.  */
      bitmap_set_bit (df->entry_block_defs, STACK_POINTER_REGNUM);

#ifdef INCOMING_RETURN_ADDR_RTX
      if (REG_P (INCOMING_RETURN_ADDR_RTX))
	bitmap_set_bit (df->entry_block_defs, REGNO (INCOMING_RETURN_ADDR_RTX));
#endif
            
      /* If STATIC_CHAIN_INCOMING_REGNUM == STATIC_CHAIN_REGNUM
	 only STATIC_CHAIN_REGNUM is defined.  If they are different,
	 we only care about the STATIC_CHAIN_INCOMING_REGNUM.  */
#ifdef STATIC_CHAIN_INCOMING_REGNUM
      bitmap_set_bit (df->entry_block_defs, STATIC_CHAIN_INCOMING_REGNUM);
#else 
#ifdef STATIC_CHAIN_REGNUM
      bitmap_set_bit (df->entry_block_defs, STATIC_CHAIN_REGNUM);
#endif
#endif
      
      r = TARGET_STRUCT_VALUE_RTX (current_function_decl, true);
      if (r && REG_P (r))
	bitmap_set_bit (df->entry_block_defs, REGNO (r));
    }

  if ((!reload_completed) || frame_pointer_needed)
    {
      /* Any reference to any pseudo before reload is a potential
	 reference of the frame pointer.  */
      bitmap_set_bit (df->entry_block_defs, FRAME_POINTER_REGNUM);
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
      /* If they are different, also mark the hard frame pointer as live.  */
      if (!LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
	bitmap_set_bit (df->entry_block_defs, HARD_FRAME_POINTER_REGNUM);
#endif
    }

  /* These registers are live everywhere.  */
  if (!reload_completed)
    {
#ifdef EH_USES
      /* The ia-64, the only machine that uses this, does not define these 
	 until after reload.  */
      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if (EH_USES (i))
	  {
	    bitmap_set_bit (df->entry_block_defs, i);
	  }
#endif
      
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
      /* Pseudos with argument area equivalences may require
	 reloading via the argument pointer.  */
      if (fixed_regs[ARG_POINTER_REGNUM])
	bitmap_set_bit (df->entry_block_defs, ARG_POINTER_REGNUM);
#endif
	  
#ifdef PIC_OFFSET_TABLE_REGNUM
      /* Any constant, or pseudo with constant equivalences, may
	 require reloading from memory using the pic register.  */
      if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
	  && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
	bitmap_set_bit (df->entry_block_defs, PIC_OFFSET_TABLE_REGNUM);
#endif
    }

  targetm.live_on_entry (df->entry_block_defs);

  EXECUTE_IF_SET_IN_BITMAP (df->entry_block_defs, 0, i, bi)
    {
      df_ref_record (dflow, regno_reg_rtx[i], &regno_reg_rtx[i], 
		     ENTRY_BLOCK_PTR, NULL, 
		     DF_REF_REG_DEF, DF_REF_ARTIFICIAL , false);
    }
}


/* Record the set of hard registers that are used in the exit block.  */

static void
df_record_exit_block_uses (struct dataflow *dflow)
{
  unsigned int i; 
  bitmap_iterator bi;
  struct df *df = dflow->df;

  bitmap_clear (df->exit_block_uses);
  
  if (!(dflow->flags & DF_HARD_REGS))
    return;

  /* If exiting needs the right stack value, consider the stack
     pointer live at the end of the function.  */
  if ((HAVE_epilogue && epilogue_completed)
      || !EXIT_IGNORE_STACK
      || (!FRAME_POINTER_REQUIRED
	  && !current_function_calls_alloca
	  && flag_omit_frame_pointer)
      || current_function_sp_is_unchanging)
    {
      bitmap_set_bit (df->exit_block_uses, STACK_POINTER_REGNUM);
    }
  
  /* Mark the frame pointer if needed at the end of the function.
     If we end up eliminating it, it will be removed from the live
     list of each basic block by reload.  */
  
  if ((!reload_completed) || frame_pointer_needed)
    {
      bitmap_set_bit (df->exit_block_uses, FRAME_POINTER_REGNUM);
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
      /* If they are different, also mark the hard frame pointer as live.  */
      if (!LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
	bitmap_set_bit (df->exit_block_uses, HARD_FRAME_POINTER_REGNUM);
#endif
    }

#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
  /* Many architectures have a GP register even without flag_pic.
     Assume the pic register is not in use, or will be handled by
     other means, if it is not fixed.  */
  if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
      && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
    bitmap_set_bit (df->exit_block_uses, PIC_OFFSET_TABLE_REGNUM);
#endif
  
  /* Mark all global registers, and all registers used by the
     epilogue as being live at the end of the function since they
     may be referenced by our caller.  */
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    if (global_regs[i] || EPILOGUE_USES (i))
      bitmap_set_bit (df->exit_block_uses, i);
  
  if (HAVE_epilogue && epilogue_completed)
    {
      /* Mark all call-saved registers that we actually used.  */
      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
	if (regs_ever_live[i] && !LOCAL_REGNO (i)
	    && !TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
	  bitmap_set_bit (df->exit_block_uses, i);
    }
  
#ifdef EH_RETURN_DATA_REGNO
  /* Mark the registers that will contain data for the handler.  */
  if (reload_completed && current_function_calls_eh_return)
    for (i = 0; ; ++i)
      {
	unsigned regno = EH_RETURN_DATA_REGNO (i);
	if (regno == INVALID_REGNUM)
	  break;
	bitmap_set_bit (df->exit_block_uses, regno);
      }
#endif

#ifdef EH_RETURN_STACKADJ_RTX
  if ((!HAVE_epilogue || ! epilogue_completed)
      && current_function_calls_eh_return)
    {
      rtx tmp = EH_RETURN_STACKADJ_RTX;
      if (tmp && REG_P (tmp))
	df_mark_reg (tmp, df->exit_block_uses);
    }
#endif

#ifdef EH_RETURN_HANDLER_RTX
  if ((!HAVE_epilogue || ! epilogue_completed)
      && current_function_calls_eh_return)
    {
      rtx tmp = EH_RETURN_HANDLER_RTX;
      if (tmp && REG_P (tmp))
	df_mark_reg (tmp, df->exit_block_uses);
    }
#endif 
  
  /* Mark function return value.  */
  diddle_return_value (df_mark_reg, (void*) df->exit_block_uses);

  if (dflow->flags & DF_HARD_REGS)
    EXECUTE_IF_SET_IN_BITMAP (df->exit_block_uses, 0, i, bi)
      df_uses_record (dflow, &regno_reg_rtx[i], 
  		      DF_REF_REG_USE, EXIT_BLOCK_PTR, NULL,
		      DF_REF_ARTIFICIAL);
}

static bool initialized = false;

/* Initialize some platform specific structures.  */

void 
df_hard_reg_init (void)
{
  int i;
#ifdef ELIMINABLE_REGS
  static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
#endif
  /* After reload, some ports add certain bits to regs_ever_live so
     this cannot be reset.  */
  
  if (!reload_completed)
    memset (regs_ever_live, 0, sizeof (regs_ever_live));

  if (initialized)
    return;

  bitmap_obstack_initialize (&persistent_obstack);

  /* Record which registers will be eliminated.  We use this in
     mark_used_regs.  */
  CLEAR_HARD_REG_SET (elim_reg_set);
  
#ifdef ELIMINABLE_REGS
  for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
    SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
#else
  SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
#endif
  
  df_invalidated_by_call = BITMAP_ALLOC (&persistent_obstack);
  
  /* Inconveniently, this is only readily available in hard reg set
     form.  */
  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
    if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
      bitmap_set_bit (df_invalidated_by_call, i);
  
  initialized = true;
}
OpenPOWER on IntegriCloud