aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.8.3/gcc/tree-ssa-pre.c
blob: 3e6a82e24ab35bf8f2a290a361a964d0838b24b9 (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
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
/* SSA-PRE for trees.
   Copyright (C) 2001-2013 Free Software Foundation, Inc.
   Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
   <stevenb@suse.de>

This file is part of GCC.

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

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

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

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "basic-block.h"
#include "gimple-pretty-print.h"
#include "tree-inline.h"
#include "tree-flow.h"
#include "gimple.h"
#include "hash-table.h"
#include "tree-iterator.h"
#include "alloc-pool.h"
#include "obstack.h"
#include "tree-pass.h"
#include "flags.h"
#include "bitmap.h"
#include "langhooks.h"
#include "cfgloop.h"
#include "tree-ssa-sccvn.h"
#include "tree-scalar-evolution.h"
#include "params.h"
#include "dbgcnt.h"
#include "domwalk.h"

/* TODO:

   1. Avail sets can be shared by making an avail_find_leader that
      walks up the dominator tree and looks in those avail sets.
      This might affect code optimality, it's unclear right now.
   2. Strength reduction can be performed by anticipating expressions
      we can repair later on.
   3. We can do back-substitution or smarter value numbering to catch
      commutative expressions split up over multiple statements.
*/

/* For ease of terminology, "expression node" in the below refers to
   every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
   represent the actual statement containing the expressions we care about,
   and we cache the value number by putting it in the expression.  */

/* Basic algorithm

   First we walk the statements to generate the AVAIL sets, the
   EXP_GEN sets, and the tmp_gen sets.  EXP_GEN sets represent the
   generation of values/expressions by a given block.  We use them
   when computing the ANTIC sets.  The AVAIL sets consist of
   SSA_NAME's that represent values, so we know what values are
   available in what blocks.  AVAIL is a forward dataflow problem.  In
   SSA, values are never killed, so we don't need a kill set, or a
   fixpoint iteration, in order to calculate the AVAIL sets.  In
   traditional parlance, AVAIL sets tell us the downsafety of the
   expressions/values.

   Next, we generate the ANTIC sets.  These sets represent the
   anticipatable expressions.  ANTIC is a backwards dataflow
   problem.  An expression is anticipatable in a given block if it could
   be generated in that block.  This means that if we had to perform
   an insertion in that block, of the value of that expression, we
   could.  Calculating the ANTIC sets requires phi translation of
   expressions, because the flow goes backwards through phis.  We must
   iterate to a fixpoint of the ANTIC sets, because we have a kill
   set.  Even in SSA form, values are not live over the entire
   function, only from their definition point onwards.  So we have to
   remove values from the ANTIC set once we go past the definition
   point of the leaders that make them up.
   compute_antic/compute_antic_aux performs this computation.

   Third, we perform insertions to make partially redundant
   expressions fully redundant.

   An expression is partially redundant (excluding partial
   anticipation) if:

   1. It is AVAIL in some, but not all, of the predecessors of a
      given block.
   2. It is ANTIC in all the predecessors.

   In order to make it fully redundant, we insert the expression into
   the predecessors where it is not available, but is ANTIC.

   For the partial anticipation case, we only perform insertion if it
   is partially anticipated in some block, and fully available in all
   of the predecessors.

   insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
   performs these steps.

   Fourth, we eliminate fully redundant expressions.
   This is a simple statement walk that replaces redundant
   calculations with the now available values.  */

/* Representations of value numbers:

   Value numbers are represented by a representative SSA_NAME.  We
   will create fake SSA_NAME's in situations where we need a
   representative but do not have one (because it is a complex
   expression).  In order to facilitate storing the value numbers in
   bitmaps, and keep the number of wasted SSA_NAME's down, we also
   associate a value_id with each value number, and create full blown
   ssa_name's only where we actually need them (IE in operands of
   existing expressions).

   Theoretically you could replace all the value_id's with
   SSA_NAME_VERSION, but this would allocate a large number of
   SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
   It would also require an additional indirection at each point we
   use the value id.  */

/* Representation of expressions on value numbers:

   Expressions consisting of value numbers are represented the same
   way as our VN internally represents them, with an additional
   "pre_expr" wrapping around them in order to facilitate storing all
   of the expressions in the same sets.  */

/* Representation of sets:

   The dataflow sets do not need to be sorted in any particular order
   for the majority of their lifetime, are simply represented as two
   bitmaps, one that keeps track of values present in the set, and one
   that keeps track of expressions present in the set.

   When we need them in topological order, we produce it on demand by
   transforming the bitmap into an array and sorting it into topo
   order.  */

/* Type of expression, used to know which member of the PRE_EXPR union
   is valid.  */

enum pre_expr_kind
{
    NAME,
    NARY,
    REFERENCE,
    CONSTANT
};

typedef union pre_expr_union_d
{
  tree name;
  tree constant;
  vn_nary_op_t nary;
  vn_reference_t reference;
} pre_expr_union;

typedef struct pre_expr_d : typed_noop_remove <pre_expr_d>
{
  enum pre_expr_kind kind;
  unsigned int id;
  pre_expr_union u;

  /* hash_table support.  */
  typedef pre_expr_d value_type;
  typedef pre_expr_d compare_type;
  static inline hashval_t hash (const pre_expr_d *);
  static inline int equal (const pre_expr_d *, const pre_expr_d *);
} *pre_expr;

#define PRE_EXPR_NAME(e) (e)->u.name
#define PRE_EXPR_NARY(e) (e)->u.nary
#define PRE_EXPR_REFERENCE(e) (e)->u.reference
#define PRE_EXPR_CONSTANT(e) (e)->u.constant

/* Compare E1 and E1 for equality.  */

inline int
pre_expr_d::equal (const value_type *e1, const compare_type *e2)
{
  if (e1->kind != e2->kind)
    return false;

  switch (e1->kind)
    {
    case CONSTANT:
      return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
				       PRE_EXPR_CONSTANT (e2));
    case NAME:
      return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
    case NARY:
      return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
    case REFERENCE:
      return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
			      PRE_EXPR_REFERENCE (e2));
    default:
      gcc_unreachable ();
    }
}

/* Hash E.  */

inline hashval_t
pre_expr_d::hash (const value_type *e)
{
  switch (e->kind)
    {
    case CONSTANT:
      return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
    case NAME:
      return SSA_NAME_VERSION (PRE_EXPR_NAME (e));
    case NARY:
      return PRE_EXPR_NARY (e)->hashcode;
    case REFERENCE:
      return PRE_EXPR_REFERENCE (e)->hashcode;
    default:
      gcc_unreachable ();
    }
}

/* Next global expression id number.  */
static unsigned int next_expression_id;

/* Mapping from expression to id number we can use in bitmap sets.  */
static vec<pre_expr> expressions;
static hash_table <pre_expr_d> expression_to_id;
static vec<unsigned> name_to_id;

/* Allocate an expression id for EXPR.  */

static inline unsigned int
alloc_expression_id (pre_expr expr)
{
  struct pre_expr_d **slot;
  /* Make sure we won't overflow. */
  gcc_assert (next_expression_id + 1 > next_expression_id);
  expr->id = next_expression_id++;
  expressions.safe_push (expr);
  if (expr->kind == NAME)
    {
      unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
      /* vec::safe_grow_cleared allocates no headroom.  Avoid frequent
	 re-allocations by using vec::reserve upfront.  There is no
	 vec::quick_grow_cleared unfortunately.  */
      unsigned old_len = name_to_id.length ();
      name_to_id.reserve (num_ssa_names - old_len);
      name_to_id.safe_grow_cleared (num_ssa_names);
      gcc_assert (name_to_id[version] == 0);
      name_to_id[version] = expr->id;
    }
  else
    {
      slot = expression_to_id.find_slot (expr, INSERT);
      gcc_assert (!*slot);
      *slot = expr;
    }
  return next_expression_id - 1;
}

/* Return the expression id for tree EXPR.  */

static inline unsigned int
get_expression_id (const pre_expr expr)
{
  return expr->id;
}

static inline unsigned int
lookup_expression_id (const pre_expr expr)
{
  struct pre_expr_d **slot;

  if (expr->kind == NAME)
    {
      unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
      if (name_to_id.length () <= version)
	return 0;
      return name_to_id[version];
    }
  else
    {
      slot = expression_to_id.find_slot (expr, NO_INSERT);
      if (!slot)
	return 0;
      return ((pre_expr)*slot)->id;
    }
}

/* Return the existing expression id for EXPR, or create one if one
   does not exist yet.  */

static inline unsigned int
get_or_alloc_expression_id (pre_expr expr)
{
  unsigned int id = lookup_expression_id (expr);
  if (id == 0)
    return alloc_expression_id (expr);
  return expr->id = id;
}

/* Return the expression that has expression id ID */

static inline pre_expr
expression_for_id (unsigned int id)
{
  return expressions[id];
}

/* Free the expression id field in all of our expressions,
   and then destroy the expressions array.  */

static void
clear_expression_ids (void)
{
  expressions.release ();
}

static alloc_pool pre_expr_pool;

/* Given an SSA_NAME NAME, get or create a pre_expr to represent it.  */

static pre_expr
get_or_alloc_expr_for_name (tree name)
{
  struct pre_expr_d expr;
  pre_expr result;
  unsigned int result_id;

  expr.kind = NAME;
  expr.id = 0;
  PRE_EXPR_NAME (&expr) = name;
  result_id = lookup_expression_id (&expr);
  if (result_id != 0)
    return expression_for_id (result_id);

  result = (pre_expr) pool_alloc (pre_expr_pool);
  result->kind = NAME;
  PRE_EXPR_NAME (result) = name;
  alloc_expression_id (result);
  return result;
}

/* An unordered bitmap set.  One bitmap tracks values, the other,
   expressions.  */
typedef struct bitmap_set
{
  bitmap_head expressions;
  bitmap_head values;
} *bitmap_set_t;

#define FOR_EACH_EXPR_ID_IN_SET(set, id, bi)		\
  EXECUTE_IF_SET_IN_BITMAP(&(set)->expressions, 0, (id), (bi))

#define FOR_EACH_VALUE_ID_IN_SET(set, id, bi)		\
  EXECUTE_IF_SET_IN_BITMAP(&(set)->values, 0, (id), (bi))

/* Mapping from value id to expressions with that value_id.  */
static vec<bitmap> value_expressions;

/* Sets that we need to keep track of.  */
typedef struct bb_bitmap_sets
{
  /* The EXP_GEN set, which represents expressions/values generated in
     a basic block.  */
  bitmap_set_t exp_gen;

  /* The PHI_GEN set, which represents PHI results generated in a
     basic block.  */
  bitmap_set_t phi_gen;

  /* The TMP_GEN set, which represents results/temporaries generated
     in a basic block. IE the LHS of an expression.  */
  bitmap_set_t tmp_gen;

  /* The AVAIL_OUT set, which represents which values are available in
     a given basic block.  */
  bitmap_set_t avail_out;

  /* The ANTIC_IN set, which represents which values are anticipatable
     in a given basic block.  */
  bitmap_set_t antic_in;

  /* The PA_IN set, which represents which values are
     partially anticipatable in a given basic block.  */
  bitmap_set_t pa_in;

  /* The NEW_SETS set, which is used during insertion to augment the
     AVAIL_OUT set of blocks with the new insertions performed during
     the current iteration.  */
  bitmap_set_t new_sets;

  /* A cache for value_dies_in_block_x.  */
  bitmap expr_dies;

  /* True if we have visited this block during ANTIC calculation.  */
  unsigned int visited : 1;

  /* True we have deferred processing this block during ANTIC
     calculation until its successor is processed.  */
  unsigned int deferred : 1;

  /* True when the block contains a call that might not return.  */
  unsigned int contains_may_not_return_call : 1;
} *bb_value_sets_t;

#define EXP_GEN(BB)	((bb_value_sets_t) ((BB)->aux))->exp_gen
#define PHI_GEN(BB)	((bb_value_sets_t) ((BB)->aux))->phi_gen
#define TMP_GEN(BB)	((bb_value_sets_t) ((BB)->aux))->tmp_gen
#define AVAIL_OUT(BB)	((bb_value_sets_t) ((BB)->aux))->avail_out
#define ANTIC_IN(BB)	((bb_value_sets_t) ((BB)->aux))->antic_in
#define PA_IN(BB)	((bb_value_sets_t) ((BB)->aux))->pa_in
#define NEW_SETS(BB)	((bb_value_sets_t) ((BB)->aux))->new_sets
#define EXPR_DIES(BB)	((bb_value_sets_t) ((BB)->aux))->expr_dies
#define BB_VISITED(BB)	((bb_value_sets_t) ((BB)->aux))->visited
#define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
#define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call


/* Basic block list in postorder.  */
static int *postorder;
static int postorder_num;

/* This structure is used to keep track of statistics on what
   optimization PRE was able to perform.  */
static struct
{
  /* The number of RHS computations eliminated by PRE.  */
  int eliminations;

  /* The number of new expressions/temporaries generated by PRE.  */
  int insertions;

  /* The number of inserts found due to partial anticipation  */
  int pa_insert;

  /* The number of new PHI nodes added by PRE.  */
  int phis;
} pre_stats;

static bool do_partial_partial;
static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int);
static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr,
				      unsigned int, bool);
static bitmap_set_t bitmap_set_new (void);
static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
					 tree);
static tree find_or_generate_expression (basic_block, tree, gimple_seq *);
static unsigned int get_expr_value_id (pre_expr);

/* We can add and remove elements and entries to and from sets
   and hash tables, so we use alloc pools for them.  */

static alloc_pool bitmap_set_pool;
static bitmap_obstack grand_bitmap_obstack;

/* Set of blocks with statements that have had their EH properties changed.  */
static bitmap need_eh_cleanup;

/* Set of blocks with statements that have had their AB properties changed.  */
static bitmap need_ab_cleanup;

/* A three tuple {e, pred, v} used to cache phi translations in the
   phi_translate_table.  */

typedef struct expr_pred_trans_d : typed_free_remove<expr_pred_trans_d>
{
  /* The expression.  */
  pre_expr e;

  /* The predecessor block along which we translated the expression.  */
  basic_block pred;

  /* The value that resulted from the translation.  */
  pre_expr v;

  /* The hashcode for the expression, pred pair. This is cached for
     speed reasons.  */
  hashval_t hashcode;

  /* hash_table support.  */
  typedef expr_pred_trans_d value_type;
  typedef expr_pred_trans_d compare_type;
  static inline hashval_t hash (const value_type *);
  static inline int equal (const value_type *, const compare_type *);
} *expr_pred_trans_t;
typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;

inline hashval_t
expr_pred_trans_d::hash (const expr_pred_trans_d *e)
{
  return e->hashcode;
}

inline int
expr_pred_trans_d::equal (const value_type *ve1,
			  const compare_type *ve2)
{
  basic_block b1 = ve1->pred;
  basic_block b2 = ve2->pred;

  /* If they are not translations for the same basic block, they can't
     be equal.  */
  if (b1 != b2)
    return false;
  return pre_expr_d::equal (ve1->e, ve2->e);
}

/* The phi_translate_table caches phi translations for a given
   expression and predecessor.  */
static hash_table <expr_pred_trans_d> phi_translate_table;

/* Search in the phi translation table for the translation of
   expression E in basic block PRED.
   Return the translated value, if found, NULL otherwise.  */

static inline pre_expr
phi_trans_lookup (pre_expr e, basic_block pred)
{
  expr_pred_trans_t *slot;
  struct expr_pred_trans_d ept;

  ept.e = e;
  ept.pred = pred;
  ept.hashcode = iterative_hash_hashval_t (pre_expr_d::hash (e), pred->index);
  slot = phi_translate_table.find_slot_with_hash (&ept, ept.hashcode,
				   NO_INSERT);
  if (!slot)
    return NULL;
  else
    return (*slot)->v;
}


/* Add the tuple mapping from {expression E, basic block PRED} to
   value V, to the phi translation table.  */

static inline void
phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
{
  expr_pred_trans_t *slot;
  expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
  new_pair->e = e;
  new_pair->pred = pred;
  new_pair->v = v;
  new_pair->hashcode = iterative_hash_hashval_t (pre_expr_d::hash (e),
						 pred->index);

  slot = phi_translate_table.find_slot_with_hash (new_pair,
				   new_pair->hashcode, INSERT);
  free (*slot);
  *slot = new_pair;
}


/* Add expression E to the expression set of value id V.  */

static void
add_to_value (unsigned int v, pre_expr e)
{
  bitmap set;

  gcc_checking_assert (get_expr_value_id (e) == v);

  if (v >= value_expressions.length ())
    {
      value_expressions.safe_grow_cleared (v + 1);
    }

  set = value_expressions[v];
  if (!set)
    {
      set = BITMAP_ALLOC (&grand_bitmap_obstack);
      value_expressions[v] = set;
    }

  bitmap_set_bit (set, get_or_alloc_expression_id (e));
}

/* Create a new bitmap set and return it.  */

static bitmap_set_t
bitmap_set_new (void)
{
  bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
  bitmap_initialize (&ret->expressions, &grand_bitmap_obstack);
  bitmap_initialize (&ret->values, &grand_bitmap_obstack);
  return ret;
}

/* Return the value id for a PRE expression EXPR.  */

static unsigned int
get_expr_value_id (pre_expr expr)
{
  unsigned int id;
  switch (expr->kind)
    {
    case CONSTANT:
      id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
      break;
    case NAME:
      id = VN_INFO (PRE_EXPR_NAME (expr))->value_id;
      break;
    case NARY:
      id = PRE_EXPR_NARY (expr)->value_id;
      break;
    case REFERENCE:
      id = PRE_EXPR_REFERENCE (expr)->value_id;
      break;
    default:
      gcc_unreachable ();
    }
  /* ???  We cannot assert that expr has a value-id (it can be 0), because
     we assign value-ids only to expressions that have a result
     in set_hashtable_value_ids.  */
  return id;
}

/* Return a SCCVN valnum (SSA name or constant) for the PRE value-id VAL.  */

static tree
sccvn_valnum_from_value_id (unsigned int val)
{
  bitmap_iterator bi;
  unsigned int i;
  bitmap exprset = value_expressions[val];
  EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
    {
      pre_expr vexpr = expression_for_id (i);
      if (vexpr->kind == NAME)
	return VN_INFO (PRE_EXPR_NAME (vexpr))->valnum;
      else if (vexpr->kind == CONSTANT)
	return PRE_EXPR_CONSTANT (vexpr);
    }
  return NULL_TREE;
}

/* Remove an expression EXPR from a bitmapped set.  */

static void
bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
{
  unsigned int val  = get_expr_value_id (expr);
  if (!value_id_constant_p (val))
    {
      bitmap_clear_bit (&set->values, val);
      bitmap_clear_bit (&set->expressions, get_expression_id (expr));
    }
}

static void
bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
			  unsigned int val, bool allow_constants)
{
  if (allow_constants || !value_id_constant_p (val))
    {
      /* We specifically expect this and only this function to be able to
	 insert constants into a set.  */
      bitmap_set_bit (&set->values, val);
      bitmap_set_bit (&set->expressions, get_or_alloc_expression_id (expr));
    }
}

/* Insert an expression EXPR into a bitmapped set.  */

static void
bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
{
  bitmap_insert_into_set_1 (set, expr, get_expr_value_id (expr), false);
}

/* Copy a bitmapped set ORIG, into bitmapped set DEST.  */

static void
bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
{
  bitmap_copy (&dest->expressions, &orig->expressions);
  bitmap_copy (&dest->values, &orig->values);
}


/* Free memory used up by SET.  */
static void
bitmap_set_free (bitmap_set_t set)
{
  bitmap_clear (&set->expressions);
  bitmap_clear (&set->values);
}


/* Generate an topological-ordered array of bitmap set SET.  */

static vec<pre_expr> 
sorted_array_from_bitmap_set (bitmap_set_t set)
{
  unsigned int i, j;
  bitmap_iterator bi, bj;
  vec<pre_expr> result;

  /* Pre-allocate roughly enough space for the array.  */
  result.create (bitmap_count_bits (&set->values));

  FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
    {
      /* The number of expressions having a given value is usually
	 relatively small.  Thus, rather than making a vector of all
	 the expressions and sorting it by value-id, we walk the values
	 and check in the reverse mapping that tells us what expressions
	 have a given value, to filter those in our set.  As a result,
	 the expressions are inserted in value-id order, which means
	 topological order.

	 If this is somehow a significant lose for some cases, we can
	 choose which set to walk based on the set size.  */
      bitmap exprset = value_expressions[i];
      EXECUTE_IF_SET_IN_BITMAP (exprset, 0, j, bj)
	{
	  if (bitmap_bit_p (&set->expressions, j))
	    result.safe_push (expression_for_id (j));
        }
    }

  return result;
}

/* Perform bitmapped set operation DEST &= ORIG.  */

static void
bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
{
  bitmap_iterator bi;
  unsigned int i;

  if (dest != orig)
    {
      bitmap_head temp;
      bitmap_initialize (&temp, &grand_bitmap_obstack);

      bitmap_and_into (&dest->values, &orig->values);
      bitmap_copy (&temp, &dest->expressions);
      EXECUTE_IF_SET_IN_BITMAP (&temp, 0, i, bi)
	{
	  pre_expr expr = expression_for_id (i);
	  unsigned int value_id = get_expr_value_id (expr);
	  if (!bitmap_bit_p (&dest->values, value_id))
	    bitmap_clear_bit (&dest->expressions, i);
	}
      bitmap_clear (&temp);
    }
}

/* Subtract all values and expressions contained in ORIG from DEST.  */

static bitmap_set_t
bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
{
  bitmap_set_t result = bitmap_set_new ();
  bitmap_iterator bi;
  unsigned int i;

  bitmap_and_compl (&result->expressions, &dest->expressions,
		    &orig->expressions);

  FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
    {
      pre_expr expr = expression_for_id (i);
      unsigned int value_id = get_expr_value_id (expr);
      bitmap_set_bit (&result->values, value_id);
    }

  return result;
}

/* Subtract all the values in bitmap set B from bitmap set A.  */

static void
bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
{
  unsigned int i;
  bitmap_iterator bi;
  bitmap_head temp;

  bitmap_initialize (&temp, &grand_bitmap_obstack);

  bitmap_copy (&temp, &a->expressions);
  EXECUTE_IF_SET_IN_BITMAP (&temp, 0, i, bi)
    {
      pre_expr expr = expression_for_id (i);
      if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
	bitmap_remove_from_set (a, expr);
    }
  bitmap_clear (&temp);
}


/* Return true if bitmapped set SET contains the value VALUE_ID.  */

static bool
bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
{
  if (value_id_constant_p (value_id))
    return true;

  if (!set || bitmap_empty_p (&set->expressions))
    return false;

  return bitmap_bit_p (&set->values, value_id);
}

static inline bool
bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
{
  return bitmap_bit_p (&set->expressions, get_expression_id (expr));
}

/* Replace an instance of value LOOKFOR with expression EXPR in SET.  */

static void
bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
			  const pre_expr expr)
{
  bitmap exprset;
  unsigned int i;
  bitmap_iterator bi;

  if (value_id_constant_p (lookfor))
    return;

  if (!bitmap_set_contains_value (set, lookfor))
    return;

  /* The number of expressions having a given value is usually
     significantly less than the total number of expressions in SET.
     Thus, rather than check, for each expression in SET, whether it
     has the value LOOKFOR, we walk the reverse mapping that tells us
     what expressions have a given value, and see if any of those
     expressions are in our set.  For large testcases, this is about
     5-10x faster than walking the bitmap.  If this is somehow a
     significant lose for some cases, we can choose which set to walk
     based on the set size.  */
  exprset = value_expressions[lookfor];
  EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
    {
      if (bitmap_clear_bit (&set->expressions, i))
	{
	  bitmap_set_bit (&set->expressions, get_expression_id (expr));
	  return;
	}
    }

  gcc_unreachable ();
}

/* Return true if two bitmap sets are equal.  */

static bool
bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
{
  return bitmap_equal_p (&a->values, &b->values);
}

/* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
   and add it otherwise.  */

static void
bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
{
  unsigned int val = get_expr_value_id (expr);

  if (bitmap_set_contains_value (set, val))
    bitmap_set_replace_value (set, val, expr);
  else
    bitmap_insert_into_set (set, expr);
}

/* Insert EXPR into SET if EXPR's value is not already present in
   SET.  */

static void
bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
{
  unsigned int val = get_expr_value_id (expr);

  gcc_checking_assert (expr->id == get_or_alloc_expression_id (expr));

  /* Constant values are always considered to be part of the set.  */
  if (value_id_constant_p (val))
    return;

  /* If the value membership changed, add the expression.  */
  if (bitmap_set_bit (&set->values, val))
    bitmap_set_bit (&set->expressions, expr->id);
}

/* Print out EXPR to outfile.  */

static void
print_pre_expr (FILE *outfile, const pre_expr expr)
{
  switch (expr->kind)
    {
    case CONSTANT:
      print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
      break;
    case NAME:
      print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
      break;
    case NARY:
      {
	unsigned int i;
	vn_nary_op_t nary = PRE_EXPR_NARY (expr);
	fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
	for (i = 0; i < nary->length; i++)
	  {
	    print_generic_expr (outfile, nary->op[i], 0);
	    if (i != (unsigned) nary->length - 1)
	      fprintf (outfile, ",");
	  }
	fprintf (outfile, "}");
      }
      break;

    case REFERENCE:
      {
	vn_reference_op_t vro;
	unsigned int i;
	vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
	fprintf (outfile, "{");
	for (i = 0;
	     ref->operands.iterate (i, &vro);
	     i++)
	  {
	    bool closebrace = false;
	    if (vro->opcode != SSA_NAME
		&& TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
	      {
		fprintf (outfile, "%s", tree_code_name [vro->opcode]);
		if (vro->op0)
		  {
		    fprintf (outfile, "<");
		    closebrace = true;
		  }
	      }
	    if (vro->op0)
	      {
		print_generic_expr (outfile, vro->op0, 0);
		if (vro->op1)
		  {
		    fprintf (outfile, ",");
		    print_generic_expr (outfile, vro->op1, 0);
		  }
		if (vro->op2)
		  {
		    fprintf (outfile, ",");
		    print_generic_expr (outfile, vro->op2, 0);
		  }
	      }
	    if (closebrace)
		fprintf (outfile, ">");
	    if (i != ref->operands.length () - 1)
	      fprintf (outfile, ",");
	  }
	fprintf (outfile, "}");
	if (ref->vuse)
	  {
	    fprintf (outfile, "@");
	    print_generic_expr (outfile, ref->vuse, 0);
	  }
      }
      break;
    }
}
void debug_pre_expr (pre_expr);

/* Like print_pre_expr but always prints to stderr.  */
DEBUG_FUNCTION void
debug_pre_expr (pre_expr e)
{
  print_pre_expr (stderr, e);
  fprintf (stderr, "\n");
}

/* Print out SET to OUTFILE.  */

static void
print_bitmap_set (FILE *outfile, bitmap_set_t set,
		  const char *setname, int blockindex)
{
  fprintf (outfile, "%s[%d] := { ", setname, blockindex);
  if (set)
    {
      bool first = true;
      unsigned i;
      bitmap_iterator bi;

      FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
	{
	  const pre_expr expr = expression_for_id (i);

	  if (!first)
	    fprintf (outfile, ", ");
	  first = false;
	  print_pre_expr (outfile, expr);

	  fprintf (outfile, " (%04d)", get_expr_value_id (expr));
	}
    }
  fprintf (outfile, " }\n");
}

void debug_bitmap_set (bitmap_set_t);

DEBUG_FUNCTION void
debug_bitmap_set (bitmap_set_t set)
{
  print_bitmap_set (stderr, set, "debug", 0);
}

void debug_bitmap_sets_for (basic_block);

DEBUG_FUNCTION void
debug_bitmap_sets_for (basic_block bb)
{
  print_bitmap_set (stderr, AVAIL_OUT (bb), "avail_out", bb->index);
  print_bitmap_set (stderr, EXP_GEN (bb), "exp_gen", bb->index);
  print_bitmap_set (stderr, PHI_GEN (bb), "phi_gen", bb->index);
  print_bitmap_set (stderr, TMP_GEN (bb), "tmp_gen", bb->index);
  print_bitmap_set (stderr, ANTIC_IN (bb), "antic_in", bb->index);
  if (do_partial_partial)
    print_bitmap_set (stderr, PA_IN (bb), "pa_in", bb->index);
  print_bitmap_set (stderr, NEW_SETS (bb), "new_sets", bb->index);
}

/* Print out the expressions that have VAL to OUTFILE.  */

static void
print_value_expressions (FILE *outfile, unsigned int val)
{
  bitmap set = value_expressions[val];
  if (set)
    {
      bitmap_set x;
      char s[10];
      sprintf (s, "%04d", val);
      x.expressions = *set;
      print_bitmap_set (outfile, &x, s, 0);
    }
}


DEBUG_FUNCTION void
debug_value_expressions (unsigned int val)
{
  print_value_expressions (stderr, val);
}

/* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
   represent it.  */

static pre_expr
get_or_alloc_expr_for_constant (tree constant)
{
  unsigned int result_id;
  unsigned int value_id;
  struct pre_expr_d expr;
  pre_expr newexpr;

  expr.kind = CONSTANT;
  PRE_EXPR_CONSTANT (&expr) = constant;
  result_id = lookup_expression_id (&expr);
  if (result_id != 0)
    return expression_for_id (result_id);

  newexpr = (pre_expr) pool_alloc (pre_expr_pool);
  newexpr->kind = CONSTANT;
  PRE_EXPR_CONSTANT (newexpr) = constant;
  alloc_expression_id (newexpr);
  value_id = get_or_alloc_constant_value_id (constant);
  add_to_value (value_id, newexpr);
  return newexpr;
}

/* Given a value id V, find the actual tree representing the constant
   value if there is one, and return it. Return NULL if we can't find
   a constant.  */

static tree
get_constant_for_value_id (unsigned int v)
{
  if (value_id_constant_p (v))
    {
      unsigned int i;
      bitmap_iterator bi;
      bitmap exprset = value_expressions[v];

      EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
	{
	  pre_expr expr = expression_for_id (i);
	  if (expr->kind == CONSTANT)
	    return PRE_EXPR_CONSTANT (expr);
	}
    }
  return NULL;
}

/* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
   Currently only supports constants and SSA_NAMES.  */
static pre_expr
get_or_alloc_expr_for (tree t)
{
  if (TREE_CODE (t) == SSA_NAME)
    return get_or_alloc_expr_for_name (t);
  else if (is_gimple_min_invariant (t))
    return get_or_alloc_expr_for_constant (t);
  else
    {
      /* More complex expressions can result from SCCVN expression
	 simplification that inserts values for them.  As they all
	 do not have VOPs the get handled by the nary ops struct.  */
      vn_nary_op_t result;
      unsigned int result_id;
      vn_nary_op_lookup (t, &result);
      if (result != NULL)
	{
	  pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
	  e->kind = NARY;
	  PRE_EXPR_NARY (e) = result;
	  result_id = lookup_expression_id (e);
	  if (result_id != 0)
	    {
	      pool_free (pre_expr_pool, e);
	      e = expression_for_id (result_id);
	      return e;
	    }
	  alloc_expression_id (e);
	  return e;
	}
    }
  return NULL;
}

/* Return the folded version of T if T, when folded, is a gimple
   min_invariant.  Otherwise, return T.  */

static pre_expr
fully_constant_expression (pre_expr e)
{
  switch (e->kind)
    {
    case CONSTANT:
      return e;
    case NARY:
      {
	vn_nary_op_t nary = PRE_EXPR_NARY (e);
	switch (TREE_CODE_CLASS (nary->opcode))
	  {
	  case tcc_binary:
	  case tcc_comparison:
	    {
	      /* We have to go from trees to pre exprs to value ids to
		 constants.  */
	      tree naryop0 = nary->op[0];
	      tree naryop1 = nary->op[1];
	      tree result;
	      if (!is_gimple_min_invariant (naryop0))
		{
		  pre_expr rep0 = get_or_alloc_expr_for (naryop0);
		  unsigned int vrep0 = get_expr_value_id (rep0);
		  tree const0 = get_constant_for_value_id (vrep0);
		  if (const0)
		    naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
		}
	      if (!is_gimple_min_invariant (naryop1))
		{
		  pre_expr rep1 = get_or_alloc_expr_for (naryop1);
		  unsigned int vrep1 = get_expr_value_id (rep1);
		  tree const1 = get_constant_for_value_id (vrep1);
		  if (const1)
		    naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
		}
	      result = fold_binary (nary->opcode, nary->type,
				    naryop0, naryop1);
	      if (result && is_gimple_min_invariant (result))
		return get_or_alloc_expr_for_constant (result);
	      /* We might have simplified the expression to a
		 SSA_NAME for example from x_1 * 1.  But we cannot
		 insert a PHI for x_1 unconditionally as x_1 might
		 not be available readily.  */
	      return e;
	    }
	  case tcc_reference:
	    if (nary->opcode != REALPART_EXPR
		&& nary->opcode != IMAGPART_EXPR
		&& nary->opcode != VIEW_CONVERT_EXPR)
	      return e;
	    /* Fallthrough.  */
	  case tcc_unary:
	    {
	      /* We have to go from trees to pre exprs to value ids to
		 constants.  */
	      tree naryop0 = nary->op[0];
	      tree const0, result;
	      if (is_gimple_min_invariant (naryop0))
		const0 = naryop0;
	      else
		{
		  pre_expr rep0 = get_or_alloc_expr_for (naryop0);
		  unsigned int vrep0 = get_expr_value_id (rep0);
		  const0 = get_constant_for_value_id (vrep0);
		}
	      result = NULL;
	      if (const0)
		{
		  tree type1 = TREE_TYPE (nary->op[0]);
		  const0 = fold_convert (type1, const0);
		  result = fold_unary (nary->opcode, nary->type, const0);
		}
	      if (result && is_gimple_min_invariant (result))
		return get_or_alloc_expr_for_constant (result);
	      return e;
	    }
	  default:
	    return e;
	  }
      }
    case REFERENCE:
      {
	vn_reference_t ref = PRE_EXPR_REFERENCE (e);
	tree folded;
	if ((folded = fully_constant_vn_reference_p (ref)))
	  return get_or_alloc_expr_for_constant (folded);
	return e;
      }
    default:
      return e;
    }
  return e;
}

/* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
   it has the value it would have in BLOCK.  Set *SAME_VALID to true
   in case the new vuse doesn't change the value id of the OPERANDS.  */

static tree
translate_vuse_through_block (vec<vn_reference_op_s> operands,
			      alias_set_type set, tree type, tree vuse,
			      basic_block phiblock,
			      basic_block block, bool *same_valid)
{
  gimple phi = SSA_NAME_DEF_STMT (vuse);
  ao_ref ref;
  edge e = NULL;
  bool use_oracle;

  *same_valid = true;

  if (gimple_bb (phi) != phiblock)
    return vuse;

  use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);

  /* Use the alias-oracle to find either the PHI node in this block,
     the first VUSE used in this block that is equivalent to vuse or
     the first VUSE which definition in this block kills the value.  */
  if (gimple_code (phi) == GIMPLE_PHI)
    e = find_edge (block, phiblock);
  else if (use_oracle)
    while (!stmt_may_clobber_ref_p_1 (phi, &ref))
      {
	vuse = gimple_vuse (phi);
	phi = SSA_NAME_DEF_STMT (vuse);
	if (gimple_bb (phi) != phiblock)
	  return vuse;
	if (gimple_code (phi) == GIMPLE_PHI)
	  {
	    e = find_edge (block, phiblock);
	    break;
	  }
      }
  else
    return NULL_TREE;

  if (e)
    {
      if (use_oracle)
	{
	  bitmap visited = NULL;
	  unsigned int cnt;
	  /* Try to find a vuse that dominates this phi node by skipping
	     non-clobbering statements.  */
	  vuse = get_continuation_for_phi (phi, &ref, &cnt, &visited, false);
	  if (visited)
	    BITMAP_FREE (visited);
	}
      else
	vuse = NULL_TREE;
      if (!vuse)
	{
	  /* If we didn't find any, the value ID can't stay the same,
	     but return the translated vuse.  */
	  *same_valid = false;
	  vuse = PHI_ARG_DEF (phi, e->dest_idx);
	}
      /* ??? We would like to return vuse here as this is the canonical
         upmost vdef that this reference is associated with.  But during
	 insertion of the references into the hash tables we only ever
	 directly insert with their direct gimple_vuse, hence returning
	 something else would make us not find the other expression.  */
      return PHI_ARG_DEF (phi, e->dest_idx);
    }

  return NULL_TREE;
}

/* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
   SET2.  This is used to avoid making a set consisting of the union
   of PA_IN and ANTIC_IN during insert.  */

static inline pre_expr
find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
{
  pre_expr result;

  result = bitmap_find_leader (set1, val);
  if (!result && set2)
    result = bitmap_find_leader (set2, val);
  return result;
}

/* Get the tree type for our PRE expression e.  */

static tree
get_expr_type (const pre_expr e)
{
  switch (e->kind)
    {
    case NAME:
      return TREE_TYPE (PRE_EXPR_NAME (e));
    case CONSTANT:
      return TREE_TYPE (PRE_EXPR_CONSTANT (e));
    case REFERENCE:
      return PRE_EXPR_REFERENCE (e)->type;
    case NARY:
      return PRE_EXPR_NARY (e)->type;
    }
  gcc_unreachable();
}

/* Get a representative SSA_NAME for a given expression.
   Since all of our sub-expressions are treated as values, we require
   them to be SSA_NAME's for simplicity.
   Prior versions of GVNPRE used to use "value handles" here, so that
   an expression would be VH.11 + VH.10 instead of d_3 + e_6.  In
   either case, the operands are really values (IE we do not expect
   them to be usable without finding leaders).  */

static tree
get_representative_for (const pre_expr e)
{
  tree name;
  unsigned int value_id = get_expr_value_id (e);

  switch (e->kind)
    {
    case NAME:
      return PRE_EXPR_NAME (e);
    case CONSTANT:
      return PRE_EXPR_CONSTANT (e);
    case NARY:
    case REFERENCE:
      {
	/* Go through all of the expressions representing this value
	   and pick out an SSA_NAME.  */
	unsigned int i;
	bitmap_iterator bi;
	bitmap exprs = value_expressions[value_id];
	EXECUTE_IF_SET_IN_BITMAP (exprs, 0, i, bi)
	  {
	    pre_expr rep = expression_for_id (i);
	    if (rep->kind == NAME)
	      return PRE_EXPR_NAME (rep);
	    else if (rep->kind == CONSTANT)
	      return PRE_EXPR_CONSTANT (rep);
	  }
      }
      break;
    }

  /* If we reached here we couldn't find an SSA_NAME.  This can
     happen when we've discovered a value that has never appeared in
     the program as set to an SSA_NAME, as the result of phi translation.
     Create one here.
     ???  We should be able to re-use this when we insert the statement
     to compute it.  */
  name = make_temp_ssa_name (get_expr_type (e), gimple_build_nop (), "pretmp");
  VN_INFO_GET (name)->value_id = value_id;
  VN_INFO (name)->valnum = name;
  /* ???  For now mark this SSA name for release by SCCVN.  */
  VN_INFO (name)->needs_insertion = true;
  add_to_value (value_id, get_or_alloc_expr_for_name (name));
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "Created SSA_NAME representative ");
      print_generic_expr (dump_file, name, 0);
      fprintf (dump_file, " for expression:");
      print_pre_expr (dump_file, e);
      fprintf (dump_file, "\n");
    }

  return name;
}



static pre_expr
phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
	       basic_block pred, basic_block phiblock);

/* Translate EXPR using phis in PHIBLOCK, so that it has the values of
   the phis in PRED.  Return NULL if we can't find a leader for each part
   of the translated expression.  */

static pre_expr
phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
		 basic_block pred, basic_block phiblock)
{
  switch (expr->kind)
    {
    case NARY:
      {
	unsigned int i;
	bool changed = false;
	vn_nary_op_t nary = PRE_EXPR_NARY (expr);
	vn_nary_op_t newnary = XALLOCAVAR (struct vn_nary_op_s,
					   sizeof_vn_nary_op (nary->length));
	memcpy (newnary, nary, sizeof_vn_nary_op (nary->length));

	for (i = 0; i < newnary->length; i++)
	  {
	    if (TREE_CODE (newnary->op[i]) != SSA_NAME)
	      continue;
	    else
	      {
                pre_expr leader, result;
		unsigned int op_val_id = VN_INFO (newnary->op[i])->value_id;
		leader = find_leader_in_sets (op_val_id, set1, set2);
                result = phi_translate (leader, set1, set2, pred, phiblock);
		if (result && result != leader)
		  {
		    tree name = get_representative_for (result);
		    if (!name)
		      return NULL;
		    newnary->op[i] = name;
		  }
		else if (!result)
		  return NULL;

		changed |= newnary->op[i] != nary->op[i];
	      }
	  }
	if (changed)
	  {
	    pre_expr constant;
	    unsigned int new_val_id;

	    tree result = vn_nary_op_lookup_pieces (newnary->length,
						    newnary->opcode,
						    newnary->type,
						    &newnary->op[0],
						    &nary);
	    if (result && is_gimple_min_invariant (result))
	      return get_or_alloc_expr_for_constant (result);

	    expr = (pre_expr) pool_alloc (pre_expr_pool);
	    expr->kind = NARY;
	    expr->id = 0;
	    if (nary)
	      {
		PRE_EXPR_NARY (expr) = nary;
		constant = fully_constant_expression (expr);
		if (constant != expr)
		  return constant;

		new_val_id = nary->value_id;
		get_or_alloc_expression_id (expr);
	      }
	    else
	      {
		new_val_id = get_next_value_id ();
		value_expressions.safe_grow_cleared (get_max_value_id() + 1);
		nary = vn_nary_op_insert_pieces (newnary->length,
						 newnary->opcode,
						 newnary->type,
						 &newnary->op[0],
						 result, new_val_id);
		PRE_EXPR_NARY (expr) = nary;
		constant = fully_constant_expression (expr);
		if (constant != expr)
		  return constant;
		get_or_alloc_expression_id (expr);
	      }
	    add_to_value (new_val_id, expr);
	  }
	return expr;
      }
      break;

    case REFERENCE:
      {
	vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
	vec<vn_reference_op_s> operands = ref->operands;
	tree vuse = ref->vuse;
	tree newvuse = vuse;
	vec<vn_reference_op_s> newoperands = vNULL;
	bool changed = false, same_valid = true;
	unsigned int i, j, n;
	vn_reference_op_t operand;
	vn_reference_t newref;

	for (i = 0, j = 0;
	     operands.iterate (i, &operand); i++, j++)
	  {
	    pre_expr opresult;
	    pre_expr leader;
	    tree op[3];
	    tree type = operand->type;
	    vn_reference_op_s newop = *operand;
	    op[0] = operand->op0;
	    op[1] = operand->op1;
	    op[2] = operand->op2;
	    for (n = 0; n < 3; ++n)
	      {
		unsigned int op_val_id;
		if (!op[n])
		  continue;
		if (TREE_CODE (op[n]) != SSA_NAME)
		  {
		    /* We can't possibly insert these.  */
		    if (n != 0
			&& !is_gimple_min_invariant (op[n]))
		      break;
		    continue;
		  }
		op_val_id = VN_INFO (op[n])->value_id;
		leader = find_leader_in_sets (op_val_id, set1, set2);
		if (!leader)
		  break;
		/* Make sure we do not recursively translate ourselves
		   like for translating a[n_1] with the leader for
		   n_1 being a[n_1].  */
		if (get_expression_id (leader) != get_expression_id (expr))
		  {
		    opresult = phi_translate (leader, set1, set2,
					      pred, phiblock);
		    if (!opresult)
		      break;
		    if (opresult != leader)
		      {
			tree name = get_representative_for (opresult);
			if (!name)
			  break;
			changed |= name != op[n];
			op[n] = name;
		      }
		  }
	      }
	    if (n != 3)
	      {
		newoperands.release ();
		return NULL;
	      }
	    if (!newoperands.exists ())
	      newoperands = operands.copy ();
	    /* We may have changed from an SSA_NAME to a constant */
	    if (newop.opcode == SSA_NAME && TREE_CODE (op[0]) != SSA_NAME)
	      newop.opcode = TREE_CODE (op[0]);
	    newop.type = type;
	    newop.op0 = op[0];
	    newop.op1 = op[1];
	    newop.op2 = op[2];
	    /* If it transforms a non-constant ARRAY_REF into a constant
	       one, adjust the constant offset.  */
	    if (newop.opcode == ARRAY_REF
		&& newop.off == -1
		&& TREE_CODE (op[0]) == INTEGER_CST
		&& TREE_CODE (op[1]) == INTEGER_CST
		&& TREE_CODE (op[2]) == INTEGER_CST)
	      {
		double_int off = tree_to_double_int (op[0]);
		off += -tree_to_double_int (op[1]);
		off *= tree_to_double_int (op[2]);
		if (off.fits_shwi ())
		  newop.off = off.low;
	      }
	    newoperands[j] = newop;
	    /* If it transforms from an SSA_NAME to an address, fold with
	       a preceding indirect reference.  */
	    if (j > 0 && op[0] && TREE_CODE (op[0]) == ADDR_EXPR
		&& newoperands[j - 1].opcode == MEM_REF)
	      vn_reference_fold_indirect (&newoperands, &j);
	  }
	if (i != operands.length ())
	  {
	    newoperands.release ();
	    return NULL;
	  }

	if (vuse)
	  {
	    newvuse = translate_vuse_through_block (newoperands,
						    ref->set, ref->type,
						    vuse, phiblock, pred,
						    &same_valid);
	    if (newvuse == NULL_TREE)
	      {
		newoperands.release ();
		return NULL;
	      }
	  }

	if (changed || newvuse != vuse)
	  {
	    unsigned int new_val_id;
	    pre_expr constant;

	    tree result = vn_reference_lookup_pieces (newvuse, ref->set,
						      ref->type,
						      newoperands,
						      &newref, VN_WALK);
	    if (result)
	      newoperands.release ();

	    /* We can always insert constants, so if we have a partial
	       redundant constant load of another type try to translate it
	       to a constant of appropriate type.  */
	    if (result && is_gimple_min_invariant (result))
	      {
		tree tem = result;
		if (!useless_type_conversion_p (ref->type, TREE_TYPE (result)))
		  {
		    tem = fold_unary (VIEW_CONVERT_EXPR, ref->type, result);
		    if (tem && !is_gimple_min_invariant (tem))
		      tem = NULL_TREE;
		  }
		if (tem)
		  return get_or_alloc_expr_for_constant (tem);
	      }

	    /* If we'd have to convert things we would need to validate
	       if we can insert the translated expression.  So fail
	       here for now - we cannot insert an alias with a different
	       type in the VN tables either, as that would assert.  */
	    if (result
		&& !useless_type_conversion_p (ref->type, TREE_TYPE (result)))
	      return NULL;
	    else if (!result && newref
		     && !useless_type_conversion_p (ref->type, newref->type))
	      {
		newoperands.release ();
		return NULL;
	      }

	    expr = (pre_expr) pool_alloc (pre_expr_pool);
	    expr->kind = REFERENCE;
	    expr->id = 0;

	    if (newref)
	      {
		PRE_EXPR_REFERENCE (expr) = newref;
		constant = fully_constant_expression (expr);
		if (constant != expr)
		  return constant;

		new_val_id = newref->value_id;
		get_or_alloc_expression_id (expr);
	      }
	    else
	      {
		if (changed || !same_valid)
		  {
		    new_val_id = get_next_value_id ();
		    value_expressions.safe_grow_cleared(get_max_value_id() + 1);
		  }
		else
		  new_val_id = ref->value_id;
		newref = vn_reference_insert_pieces (newvuse, ref->set,
						     ref->type,
						     newoperands,
						     result, new_val_id);
		newoperands.create (0);
		PRE_EXPR_REFERENCE (expr) = newref;
		constant = fully_constant_expression (expr);
		if (constant != expr)
		  return constant;
		get_or_alloc_expression_id (expr);
	      }
	    add_to_value (new_val_id, expr);
	  }
	newoperands.release ();
	return expr;
      }
      break;

    case NAME:
      {
	tree name = PRE_EXPR_NAME (expr);
	gimple def_stmt = SSA_NAME_DEF_STMT (name);
	/* If the SSA name is defined by a PHI node in this block,
	   translate it.  */
	if (gimple_code (def_stmt) == GIMPLE_PHI
	    && gimple_bb (def_stmt) == phiblock)
	  {
	    edge e = find_edge (pred, gimple_bb (def_stmt));
	    tree def = PHI_ARG_DEF (def_stmt, e->dest_idx);

	    /* Handle constant. */
	    if (is_gimple_min_invariant (def))
	      return get_or_alloc_expr_for_constant (def);

	    return get_or_alloc_expr_for_name (def);
	  }
	/* Otherwise return it unchanged - it will get cleaned if its
	   value is not available in PREDs AVAIL_OUT set of expressions.  */
	return expr;
      }

    default:
      gcc_unreachable ();
    }
}

/* Wrapper around phi_translate_1 providing caching functionality.  */

static pre_expr
phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
	       basic_block pred, basic_block phiblock)
{
  pre_expr phitrans;

  if (!expr)
    return NULL;

  /* Constants contain no values that need translation.  */
  if (expr->kind == CONSTANT)
    return expr;

  if (value_id_constant_p (get_expr_value_id (expr)))
    return expr;

  if (expr->kind != NAME)
    {
      phitrans = phi_trans_lookup (expr, pred);
      if (phitrans)
	return phitrans;
    }

  /* Translate.  */
  phitrans = phi_translate_1 (expr, set1, set2, pred, phiblock);

  /* Don't add empty translations to the cache.  Neither add
     translations of NAMEs as those are cheap to translate.  */
  if (phitrans
      && expr->kind != NAME)
    phi_trans_add (expr, phitrans, pred);

  return phitrans;
}


/* For each expression in SET, translate the values through phi nodes
   in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
   expressions in DEST.  */

static void
phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
		   basic_block phiblock)
{
  vec<pre_expr> exprs;
  pre_expr expr;
  int i;

  if (gimple_seq_empty_p (phi_nodes (phiblock)))
    {
      bitmap_set_copy (dest, set);
      return;
    }

  exprs = sorted_array_from_bitmap_set (set);
  FOR_EACH_VEC_ELT (exprs, i, expr)
    {
      pre_expr translated;
      translated = phi_translate (expr, set, NULL, pred, phiblock);
      if (!translated)
	continue;

      /* We might end up with multiple expressions from SET being
	 translated to the same value.  In this case we do not want
	 to retain the NARY or REFERENCE expression but prefer a NAME
	 which would be the leader.  */
      if (translated->kind == NAME)
	bitmap_value_replace_in_set (dest, translated);
      else
	bitmap_value_insert_into_set (dest, translated);
    }
  exprs.release ();
}

/* Find the leader for a value (i.e., the name representing that
   value) in a given set, and return it.  If STMT is non-NULL it
   makes sure the defining statement for the leader dominates it.
   Return NULL if no leader is found.  */

static pre_expr
bitmap_find_leader (bitmap_set_t set, unsigned int val)
{
  if (value_id_constant_p (val))
    {
      unsigned int i;
      bitmap_iterator bi;
      bitmap exprset = value_expressions[val];

      EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
	{
	  pre_expr expr = expression_for_id (i);
	  if (expr->kind == CONSTANT)
	    return expr;
	}
    }
  if (bitmap_set_contains_value (set, val))
    {
      /* Rather than walk the entire bitmap of expressions, and see
	 whether any of them has the value we are looking for, we look
	 at the reverse mapping, which tells us the set of expressions
	 that have a given value (IE value->expressions with that
	 value) and see if any of those expressions are in our set.
	 The number of expressions per value is usually significantly
	 less than the number of expressions in the set.  In fact, for
	 large testcases, doing it this way is roughly 5-10x faster
	 than walking the bitmap.
	 If this is somehow a significant lose for some cases, we can
	 choose which set to walk based on which set is smaller.  */
      unsigned int i;
      bitmap_iterator bi;
      bitmap exprset = value_expressions[val];

      EXECUTE_IF_AND_IN_BITMAP (exprset, &set->expressions, 0, i, bi)
	return expression_for_id (i);
    }
  return NULL;
}

/* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
   BLOCK by seeing if it is not killed in the block.  Note that we are
   only determining whether there is a store that kills it.  Because
   of the order in which clean iterates over values, we are guaranteed
   that altered operands will have caused us to be eliminated from the
   ANTIC_IN set already.  */

static bool
value_dies_in_block_x (pre_expr expr, basic_block block)
{
  tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
  vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
  gimple def;
  gimple_stmt_iterator gsi;
  unsigned id = get_expression_id (expr);
  bool res = false;
  ao_ref ref;

  if (!vuse)
    return false;

  /* Lookup a previously calculated result.  */
  if (EXPR_DIES (block)
      && bitmap_bit_p (EXPR_DIES (block), id * 2))
    return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);

  /* A memory expression {e, VUSE} dies in the block if there is a
     statement that may clobber e.  If, starting statement walk from the
     top of the basic block, a statement uses VUSE there can be no kill
     inbetween that use and the original statement that loaded {e, VUSE},
     so we can stop walking.  */
  ref.base = NULL_TREE;
  for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      tree def_vuse, def_vdef;
      def = gsi_stmt (gsi);
      def_vuse = gimple_vuse (def);
      def_vdef = gimple_vdef (def);

      /* Not a memory statement.  */
      if (!def_vuse)
	continue;

      /* Not a may-def.  */
      if (!def_vdef)
	{
	  /* A load with the same VUSE, we're done.  */
	  if (def_vuse == vuse)
	    break;

	  continue;
	}

      /* Init ref only if we really need it.  */
      if (ref.base == NULL_TREE
	  && !ao_ref_init_from_vn_reference (&ref, refx->set, refx->type,
					     refx->operands))
	{
	  res = true;
	  break;
	}
      /* If the statement may clobber expr, it dies.  */
      if (stmt_may_clobber_ref_p_1 (def, &ref))
	{
	  res = true;
	  break;
	}
    }

  /* Remember the result.  */
  if (!EXPR_DIES (block))
    EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
  bitmap_set_bit (EXPR_DIES (block), id * 2);
  if (res)
    bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);

  return res;
}


/* Determine if OP is valid in SET1 U SET2, which it is when the union
   contains its value-id.  */

static bool
op_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, tree op)
{
  if (op && TREE_CODE (op) == SSA_NAME)
    {
      unsigned int value_id = VN_INFO (op)->value_id;
      if (!(bitmap_set_contains_value (set1, value_id)
	    || (set2 && bitmap_set_contains_value  (set2, value_id))))
	return false;
    }
  return true;
}

/* Determine if the expression EXPR is valid in SET1 U SET2.
   ONLY SET2 CAN BE NULL.
   This means that we have a leader for each part of the expression
   (if it consists of values), or the expression is an SSA_NAME.
   For loads/calls, we also see if the vuse is killed in this block.  */

static bool
valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
	       basic_block block)
{
  switch (expr->kind)
    {
    case NAME:
      return bitmap_find_leader (AVAIL_OUT (block),
				 get_expr_value_id (expr)) != NULL;
    case NARY:
      {
	unsigned int i;
	vn_nary_op_t nary = PRE_EXPR_NARY (expr);
	for (i = 0; i < nary->length; i++)
	  if (!op_valid_in_sets (set1, set2, nary->op[i]))
	    return false;
	return true;
      }
      break;
    case REFERENCE:
      {
	vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
	vn_reference_op_t vro;
	unsigned int i;

	FOR_EACH_VEC_ELT (ref->operands, i, vro)
	  {
	    if (!op_valid_in_sets (set1, set2, vro->op0)
		|| !op_valid_in_sets (set1, set2, vro->op1)
		|| !op_valid_in_sets (set1, set2, vro->op2))
	      return false;
	  }
	return true;
      }
    default:
      gcc_unreachable ();
    }
}

/* Clean the set of expressions that are no longer valid in SET1 or
   SET2.  This means expressions that are made up of values we have no
   leaders for in SET1 or SET2.  This version is used for partial
   anticipation, which means it is not valid in either ANTIC_IN or
   PA_IN.  */

static void
dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
{
  vec<pre_expr> exprs = sorted_array_from_bitmap_set (set1);
  pre_expr expr;
  int i;

  FOR_EACH_VEC_ELT (exprs, i, expr)
    {
      if (!valid_in_sets (set1, set2, expr, block))
	bitmap_remove_from_set (set1, expr);
    }
  exprs.release ();
}

/* Clean the set of expressions that are no longer valid in SET.  This
   means expressions that are made up of values we have no leaders for
   in SET.  */

static void
clean (bitmap_set_t set, basic_block block)
{
  vec<pre_expr> exprs = sorted_array_from_bitmap_set (set);
  pre_expr expr;
  int i;

  FOR_EACH_VEC_ELT (exprs, i, expr)
    {
      if (!valid_in_sets (set, NULL, expr, block))
	bitmap_remove_from_set (set, expr);
    }
  exprs.release ();
}

/* Clean the set of expressions that are no longer valid in SET because
   they are clobbered in BLOCK or because they trap and may not be executed.  */

static void
prune_clobbered_mems (bitmap_set_t set, basic_block block)
{
  bitmap_iterator bi;
  unsigned i;

  FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
    {
      pre_expr expr = expression_for_id (i);
      if (expr->kind == REFERENCE)
	{
	  vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
	  if (ref->vuse)
	    {
	      gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
	      if (!gimple_nop_p (def_stmt)
		  && ((gimple_bb (def_stmt) != block
		       && !dominated_by_p (CDI_DOMINATORS,
					   block, gimple_bb (def_stmt)))
		      || (gimple_bb (def_stmt) == block
			  && value_dies_in_block_x (expr, block))))
		bitmap_remove_from_set (set, expr);
	    }
	}
      else if (expr->kind == NARY)
	{
	  vn_nary_op_t nary = PRE_EXPR_NARY (expr);
	  /* If the NARY may trap make sure the block does not contain
	     a possible exit point.
	     ???  This is overly conservative if we translate AVAIL_OUT
	     as the available expression might be after the exit point.  */
	  if (BB_MAY_NOTRETURN (block)
	      && vn_nary_may_trap (nary))
	    bitmap_remove_from_set (set, expr);
	}
    }
}

static sbitmap has_abnormal_preds;

/* List of blocks that may have changed during ANTIC computation and
   thus need to be iterated over.  */

static sbitmap changed_blocks;

/* Decide whether to defer a block for a later iteration, or PHI
   translate SOURCE to DEST using phis in PHIBLOCK.  Return false if we
   should defer the block, and true if we processed it.  */

static bool
defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
			      basic_block block, basic_block phiblock)
{
  if (!BB_VISITED (phiblock))
    {
      bitmap_set_bit (changed_blocks, block->index);
      BB_VISITED (block) = 0;
      BB_DEFERRED (block) = 1;
      return false;
    }
  else
    phi_translate_set (dest, source, block, phiblock);
  return true;
}

/* Compute the ANTIC set for BLOCK.

   If succs(BLOCK) > 1 then
     ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
   else if succs(BLOCK) == 1 then
     ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])

   ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
*/

static bool
compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
{
  bool changed = false;
  bitmap_set_t S, old, ANTIC_OUT;
  bitmap_iterator bi;
  unsigned int bii;
  edge e;
  edge_iterator ei;

  old = ANTIC_OUT = S = NULL;
  BB_VISITED (block) = 1;

  /* If any edges from predecessors are abnormal, antic_in is empty,
     so do nothing.  */
  if (block_has_abnormal_pred_edge)
    goto maybe_dump_sets;

  old = ANTIC_IN (block);
  ANTIC_OUT = bitmap_set_new ();

  /* If the block has no successors, ANTIC_OUT is empty.  */
  if (EDGE_COUNT (block->succs) == 0)
    ;
  /* If we have one successor, we could have some phi nodes to
     translate through.  */
  else if (single_succ_p (block))
    {
      basic_block succ_bb = single_succ (block);

      /* We trade iterations of the dataflow equations for having to
	 phi translate the maximal set, which is incredibly slow
	 (since the maximal set often has 300+ members, even when you
	 have a small number of blocks).
	 Basically, we defer the computation of ANTIC for this block
	 until we have processed it's successor, which will inevitably
	 have a *much* smaller set of values to phi translate once
	 clean has been run on it.
	 The cost of doing this is that we technically perform more
	 iterations, however, they are lower cost iterations.

	 Timings for PRE on tramp3d-v4:
	 without maximal set fix: 11 seconds
	 with maximal set fix/without deferring: 26 seconds
	 with maximal set fix/with deferring: 11 seconds
     */

      if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
					block, succ_bb))
	{
	  changed = true;
	  goto maybe_dump_sets;
	}
    }
  /* If we have multiple successors, we take the intersection of all of
     them.  Note that in the case of loop exit phi nodes, we may have
     phis to translate through.  */
  else
    {
      vec<basic_block> worklist;
      size_t i;
      basic_block bprime, first = NULL;

      worklist.create (EDGE_COUNT (block->succs));
      FOR_EACH_EDGE (e, ei, block->succs)
	{
	  if (!first
	      && BB_VISITED (e->dest))
	    first = e->dest;
	  else if (BB_VISITED (e->dest))
	    worklist.quick_push (e->dest);
	}

      /* Of multiple successors we have to have visited one already.  */
      if (!first)
	{
	  bitmap_set_bit (changed_blocks, block->index);
	  BB_VISITED (block) = 0;
	  BB_DEFERRED (block) = 1;
	  changed = true;
	  worklist.release ();
	  goto maybe_dump_sets;
	}

      if (!gimple_seq_empty_p (phi_nodes (first)))
	phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
      else
	bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));

      FOR_EACH_VEC_ELT (worklist, i, bprime)
	{
	  if (!gimple_seq_empty_p (phi_nodes (bprime)))
	    {
	      bitmap_set_t tmp = bitmap_set_new ();
	      phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
	      bitmap_set_and (ANTIC_OUT, tmp);
	      bitmap_set_free (tmp);
	    }
	  else
	    bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
	}
      worklist.release ();
    }

  /* Prune expressions that are clobbered in block and thus become
     invalid if translated from ANTIC_OUT to ANTIC_IN.  */
  prune_clobbered_mems (ANTIC_OUT, block);

  /* Generate ANTIC_OUT - TMP_GEN.  */
  S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));

  /* Start ANTIC_IN with EXP_GEN - TMP_GEN.  */
  ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
					  TMP_GEN (block));

  /* Then union in the ANTIC_OUT - TMP_GEN values,
     to get ANTIC_OUT U EXP_GEN - TMP_GEN */
  FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
    bitmap_value_insert_into_set (ANTIC_IN (block),
				  expression_for_id (bii));

  clean (ANTIC_IN (block), block);

  if (!bitmap_set_equal (old, ANTIC_IN (block)))
    {
      changed = true;
      bitmap_set_bit (changed_blocks, block->index);
      FOR_EACH_EDGE (e, ei, block->preds)
	bitmap_set_bit (changed_blocks, e->src->index);
    }
  else
    bitmap_clear_bit (changed_blocks, block->index);

 maybe_dump_sets:
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      if (!BB_DEFERRED (block) || BB_VISITED (block))
	{
	  if (ANTIC_OUT)
	    print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);

	  print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
			    block->index);

	  if (S)
	    print_bitmap_set (dump_file, S, "S", block->index);
	}
      else
	{
	  fprintf (dump_file,
		   "Block %d was deferred for a future iteration.\n",
		   block->index);
	}
    }
  if (old)
    bitmap_set_free (old);
  if (S)
    bitmap_set_free (S);
  if (ANTIC_OUT)
    bitmap_set_free (ANTIC_OUT);
  return changed;
}

/* Compute PARTIAL_ANTIC for BLOCK.

   If succs(BLOCK) > 1 then
     PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
     in ANTIC_OUT for all succ(BLOCK)
   else if succs(BLOCK) == 1 then
     PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])

   PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
				  - ANTIC_IN[BLOCK])

*/
static bool
compute_partial_antic_aux (basic_block block,
			   bool block_has_abnormal_pred_edge)
{
  bool changed = false;
  bitmap_set_t old_PA_IN;
  bitmap_set_t PA_OUT;
  edge e;
  edge_iterator ei;
  unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);

  old_PA_IN = PA_OUT = NULL;

  /* If any edges from predecessors are abnormal, antic_in is empty,
     so do nothing.  */
  if (block_has_abnormal_pred_edge)
    goto maybe_dump_sets;

  /* If there are too many partially anticipatable values in the
     block, phi_translate_set can take an exponential time: stop
     before the translation starts.  */
  if (max_pa
      && single_succ_p (block)
      && bitmap_count_bits (&PA_IN (single_succ (block))->values) > max_pa)
    goto maybe_dump_sets;

  old_PA_IN = PA_IN (block);
  PA_OUT = bitmap_set_new ();

  /* If the block has no successors, ANTIC_OUT is empty.  */
  if (EDGE_COUNT (block->succs) == 0)
    ;
  /* If we have one successor, we could have some phi nodes to
     translate through.  Note that we can't phi translate across DFS
     back edges in partial antic, because it uses a union operation on
     the successors.  For recurrences like IV's, we will end up
     generating a new value in the set on each go around (i + 3 (VH.1)
     VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever.  */
  else if (single_succ_p (block))
    {
      basic_block succ = single_succ (block);
      if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
	phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
    }
  /* If we have multiple successors, we take the union of all of
     them.  */
  else
    {
      vec<basic_block> worklist;
      size_t i;
      basic_block bprime;

      worklist.create (EDGE_COUNT (block->succs));
      FOR_EACH_EDGE (e, ei, block->succs)
	{
	  if (e->flags & EDGE_DFS_BACK)
	    continue;
	  worklist.quick_push (e->dest);
	}
      if (worklist.length () > 0)
	{
	  FOR_EACH_VEC_ELT (worklist, i, bprime)
	    {
	      unsigned int i;
	      bitmap_iterator bi;

	      FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
		bitmap_value_insert_into_set (PA_OUT,
					      expression_for_id (i));
	      if (!gimple_seq_empty_p (phi_nodes (bprime)))
		{
		  bitmap_set_t pa_in = bitmap_set_new ();
		  phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
		  FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
		    bitmap_value_insert_into_set (PA_OUT,
						  expression_for_id (i));
		  bitmap_set_free (pa_in);
		}
	      else
		FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
		  bitmap_value_insert_into_set (PA_OUT,
						expression_for_id (i));
	    }
	}
      worklist.release ();
    }

  /* Prune expressions that are clobbered in block and thus become
     invalid if translated from PA_OUT to PA_IN.  */
  prune_clobbered_mems (PA_OUT, block);

  /* PA_IN starts with PA_OUT - TMP_GEN.
     Then we subtract things from ANTIC_IN.  */
  PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));

  /* For partial antic, we want to put back in the phi results, since
     we will properly avoid making them partially antic over backedges.  */
  bitmap_ior_into (&PA_IN (block)->values, &PHI_GEN (block)->values);
  bitmap_ior_into (&PA_IN (block)->expressions, &PHI_GEN (block)->expressions);

  /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
  bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));

  dependent_clean (PA_IN (block), ANTIC_IN (block), block);

  if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
    {
      changed = true;
      bitmap_set_bit (changed_blocks, block->index);
      FOR_EACH_EDGE (e, ei, block->preds)
	bitmap_set_bit (changed_blocks, e->src->index);
    }
  else
    bitmap_clear_bit (changed_blocks, block->index);

 maybe_dump_sets:
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      if (PA_OUT)
	print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);

      print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
    }
  if (old_PA_IN)
    bitmap_set_free (old_PA_IN);
  if (PA_OUT)
    bitmap_set_free (PA_OUT);
  return changed;
}

/* Compute ANTIC and partial ANTIC sets.  */

static void
compute_antic (void)
{
  bool changed = true;
  int num_iterations = 0;
  basic_block block;
  int i;

  /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
     We pre-build the map of blocks with incoming abnormal edges here.  */
  has_abnormal_preds = sbitmap_alloc (last_basic_block);
  bitmap_clear (has_abnormal_preds);

  FOR_ALL_BB (block)
    {
      edge_iterator ei;
      edge e;

      FOR_EACH_EDGE (e, ei, block->preds)
	{
	  e->flags &= ~EDGE_DFS_BACK;
	  if (e->flags & EDGE_ABNORMAL)
	    {
	      bitmap_set_bit (has_abnormal_preds, block->index);
	      break;
	    }
	}

      BB_VISITED (block) = 0;
      BB_DEFERRED (block) = 0;

      /* While we are here, give empty ANTIC_IN sets to each block.  */
      ANTIC_IN (block) = bitmap_set_new ();
      PA_IN (block) = bitmap_set_new ();
    }

  /* At the exit block we anticipate nothing.  */
  BB_VISITED (EXIT_BLOCK_PTR) = 1;

  changed_blocks = sbitmap_alloc (last_basic_block + 1);
  bitmap_ones (changed_blocks);
  while (changed)
    {
      if (dump_file && (dump_flags & TDF_DETAILS))
	fprintf (dump_file, "Starting iteration %d\n", num_iterations);
      /* ???  We need to clear our PHI translation cache here as the
         ANTIC sets shrink and we restrict valid translations to
	 those having operands with leaders in ANTIC.  Same below
	 for PA ANTIC computation.  */
      num_iterations++;
      changed = false;
      for (i = postorder_num - 1; i >= 0; i--)
	{
	  if (bitmap_bit_p (changed_blocks, postorder[i]))
	    {
	      basic_block block = BASIC_BLOCK (postorder[i]);
	      changed |= compute_antic_aux (block,
					    bitmap_bit_p (has_abnormal_preds,
						      block->index));
	    }
	}
      /* Theoretically possible, but *highly* unlikely.  */
      gcc_checking_assert (num_iterations < 500);
    }

  statistics_histogram_event (cfun, "compute_antic iterations",
			      num_iterations);

  if (do_partial_partial)
    {
      bitmap_ones (changed_blocks);
      mark_dfs_back_edges ();
      num_iterations = 0;
      changed = true;
      while (changed)
	{
	  if (dump_file && (dump_flags & TDF_DETAILS))
	    fprintf (dump_file, "Starting iteration %d\n", num_iterations);
	  num_iterations++;
	  changed = false;
	  for (i = postorder_num - 1 ; i >= 0; i--)
	    {
	      if (bitmap_bit_p (changed_blocks, postorder[i]))
		{
		  basic_block block = BASIC_BLOCK (postorder[i]);
		  changed
		    |= compute_partial_antic_aux (block,
						  bitmap_bit_p (has_abnormal_preds,
							    block->index));
		}
	    }
	  /* Theoretically possible, but *highly* unlikely.  */
	  gcc_checking_assert (num_iterations < 500);
	}
      statistics_histogram_event (cfun, "compute_partial_antic iterations",
				  num_iterations);
    }
  sbitmap_free (has_abnormal_preds);
  sbitmap_free (changed_blocks);
}


/* Inserted expressions are placed onto this worklist, which is used
   for performing quick dead code elimination of insertions we made
   that didn't turn out to be necessary.   */
static bitmap inserted_exprs;

/* The actual worker for create_component_ref_by_pieces.  */

static tree
create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
				  unsigned int *operand, gimple_seq *stmts)
{
  vn_reference_op_t currop = &ref->operands[*operand];
  tree genop;
  ++*operand;
  switch (currop->opcode)
    {
    case CALL_EXPR:
      {
	tree folded, sc = NULL_TREE;
	unsigned int nargs = 0;
	tree fn, *args;
	if (TREE_CODE (currop->op0) == FUNCTION_DECL)
	  fn = currop->op0;
	else
	  fn = find_or_generate_expression (block, currop->op0, stmts);
	if (!fn)
	  return NULL_TREE;
	if (currop->op1)
	  {
	    sc = find_or_generate_expression (block, currop->op1, stmts);
	    if (!sc)
	      return NULL_TREE;
	  }
	args = XNEWVEC (tree, ref->operands.length () - 1);
	while (*operand < ref->operands.length ())
	  {
	    args[nargs] = create_component_ref_by_pieces_1 (block, ref,
							    operand, stmts);
	    if (!args[nargs])
	      return NULL_TREE;
	    nargs++;
	  }
	folded = build_call_array (currop->type,
				   (TREE_CODE (fn) == FUNCTION_DECL
				    ? build_fold_addr_expr (fn) : fn),
				   nargs, args);
	free (args);
	if (sc)
	  CALL_EXPR_STATIC_CHAIN (folded) = sc;
	return folded;
      }

    case MEM_REF:
      {
	tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
							stmts);
	if (!baseop)
	  return NULL_TREE;
	tree offset = currop->op0;
	if (TREE_CODE (baseop) == ADDR_EXPR
	    && handled_component_p (TREE_OPERAND (baseop, 0)))
	  {
	    HOST_WIDE_INT off;
	    tree base;
	    base = get_addr_base_and_unit_offset (TREE_OPERAND (baseop, 0),
						  &off);
	    gcc_assert (base);
	    offset = int_const_binop (PLUS_EXPR, offset,
				      build_int_cst (TREE_TYPE (offset),
						     off));
	    baseop = build_fold_addr_expr (base);
	  }
	return fold_build2 (MEM_REF, currop->type, baseop, offset);
      }

    case TARGET_MEM_REF:
      {
	tree genop0 = NULL_TREE, genop1 = NULL_TREE;
	vn_reference_op_t nextop = &ref->operands[++*operand];
	tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
							stmts);
	if (!baseop)
	  return NULL_TREE;
	if (currop->op0)
	  {
	    genop0 = find_or_generate_expression (block, currop->op0, stmts);
	    if (!genop0)
	      return NULL_TREE;
	  }
	if (nextop->op0)
	  {
	    genop1 = find_or_generate_expression (block, nextop->op0, stmts);
	    if (!genop1)
	      return NULL_TREE;
	  }
	return build5 (TARGET_MEM_REF, currop->type,
		       baseop, currop->op2, genop0, currop->op1, genop1);
      }

    case ADDR_EXPR:
      if (currop->op0)
	{
	  gcc_assert (is_gimple_min_invariant (currop->op0));
	  return currop->op0;
	}
      /* Fallthrough.  */
    case REALPART_EXPR:
    case IMAGPART_EXPR:
    case VIEW_CONVERT_EXPR:
      {
	tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
							stmts);
	if (!genop0)
	  return NULL_TREE;
	return fold_build1 (currop->opcode, currop->type, genop0);
      }

    case WITH_SIZE_EXPR:
      {
	tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
							stmts);
	if (!genop0)
	  return NULL_TREE;
	tree genop1 = find_or_generate_expression (block, currop->op0, stmts);
	if (!genop1)
	  return NULL_TREE;
	return fold_build2 (currop->opcode, currop->type, genop0, genop1);
      }

    case BIT_FIELD_REF:
      {
	tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
							stmts);
	if (!genop0)
	  return NULL_TREE;
	tree op1 = currop->op0;
	tree op2 = currop->op1;
	return fold_build3 (BIT_FIELD_REF, currop->type, genop0, op1, op2);
      }

      /* For array ref vn_reference_op's, operand 1 of the array ref
	 is op0 of the reference op and operand 3 of the array ref is
	 op1.  */
    case ARRAY_RANGE_REF:
    case ARRAY_REF:
      {
	tree genop0;
	tree genop1 = currop->op0;
	tree genop2 = currop->op1;
	tree genop3 = currop->op2;
	genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
						   stmts);
	if (!genop0)
	  return NULL_TREE;
	genop1 = find_or_generate_expression (block, genop1, stmts);
	if (!genop1)
	  return NULL_TREE;
	if (genop2)
	  {
	    tree domain_type = TYPE_DOMAIN (TREE_TYPE (genop0));
	    /* Drop zero minimum index if redundant.  */
	    if (integer_zerop (genop2)
		&& (!domain_type
		    || integer_zerop (TYPE_MIN_VALUE (domain_type))))
	      genop2 = NULL_TREE;
	    else
	      {
		genop2 = find_or_generate_expression (block, genop2, stmts);
		if (!genop2)
		  return NULL_TREE;
	      }
	  }
	if (genop3)
	  {
	    tree elmt_type = TREE_TYPE (TREE_TYPE (genop0));
	    /* We can't always put a size in units of the element alignment
	       here as the element alignment may be not visible.  See
	       PR43783.  Simply drop the element size for constant
	       sizes.  */
	    if (tree_int_cst_equal (genop3, TYPE_SIZE_UNIT (elmt_type)))
	      genop3 = NULL_TREE;
	    else
	      {
		genop3 = size_binop (EXACT_DIV_EXPR, genop3,
				     size_int (TYPE_ALIGN_UNIT (elmt_type)));
		genop3 = find_or_generate_expression (block, genop3, stmts);
		if (!genop3)
		  return NULL_TREE;
	      }
	  }
	return build4 (currop->opcode, currop->type, genop0, genop1,
		       genop2, genop3);
      }
    case COMPONENT_REF:
      {
	tree op0;
	tree op1;
	tree genop2 = currop->op1;
	op0 = create_component_ref_by_pieces_1 (block, ref, operand, stmts);
	if (!op0)
	  return NULL_TREE;
	/* op1 should be a FIELD_DECL, which are represented by themselves.  */
	op1 = currop->op0;
	if (genop2)
	  {
	    genop2 = find_or_generate_expression (block, genop2, stmts);
	    if (!genop2)
	      return NULL_TREE;
	  }
	return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1, genop2);
      }

    case SSA_NAME:
      {
	genop = find_or_generate_expression (block, currop->op0, stmts);
	return genop;
      }
    case STRING_CST:
    case INTEGER_CST:
    case COMPLEX_CST:
    case VECTOR_CST:
    case REAL_CST:
    case CONSTRUCTOR:
    case VAR_DECL:
    case PARM_DECL:
    case CONST_DECL:
    case RESULT_DECL:
    case FUNCTION_DECL:
      return currop->op0;

    default:
      gcc_unreachable ();
    }
}

/* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
   COMPONENT_REF or MEM_REF or ARRAY_REF portion, because we'd end up with
   trying to rename aggregates into ssa form directly, which is a no no.

   Thus, this routine doesn't create temporaries, it just builds a
   single access expression for the array, calling
   find_or_generate_expression to build the innermost pieces.

   This function is a subroutine of create_expression_by_pieces, and
   should not be called on it's own unless you really know what you
   are doing.  */

static tree
create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
				gimple_seq *stmts)
{
  unsigned int op = 0;
  return create_component_ref_by_pieces_1 (block, ref, &op, stmts);
}

/* Find a simple leader for an expression, or generate one using
   create_expression_by_pieces from a NARY expression for the value.
   BLOCK is the basic_block we are looking for leaders in.
   OP is the tree expression to find a leader for or generate.
   Returns the leader or NULL_TREE on failure.  */

static tree
find_or_generate_expression (basic_block block, tree op, gimple_seq *stmts)
{
  pre_expr expr = get_or_alloc_expr_for (op);
  unsigned int lookfor = get_expr_value_id (expr);
  pre_expr leader = bitmap_find_leader (AVAIL_OUT (block), lookfor);
  if (leader)
    {
      if (leader->kind == NAME)
	return PRE_EXPR_NAME (leader);
      else if (leader->kind == CONSTANT)
	return PRE_EXPR_CONSTANT (leader);

      /* Defer.  */
      return NULL_TREE;
    }

  /* It must be a complex expression, so generate it recursively.  Note
     that this is only necessary to handle gcc.dg/tree-ssa/ssa-pre28.c
     where the insert algorithm fails to insert a required expression.  */
  bitmap exprset = value_expressions[lookfor];
  bitmap_iterator bi;
  unsigned int i;
  EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
    {
      pre_expr temp = expression_for_id (i);
      /* We cannot insert random REFERENCE expressions at arbitrary
	 places.  We can insert NARYs which eventually re-materializes
	 its operand values.  */
      if (temp->kind == NARY)
	return create_expression_by_pieces (block, temp, stmts,
					    get_expr_type (expr));
    }

  /* Defer.  */
  return NULL_TREE;
}

#define NECESSARY GF_PLF_1

/* Create an expression in pieces, so that we can handle very complex
   expressions that may be ANTIC, but not necessary GIMPLE.
   BLOCK is the basic block the expression will be inserted into,
   EXPR is the expression to insert (in value form)
   STMTS is a statement list to append the necessary insertions into.

   This function will die if we hit some value that shouldn't be
   ANTIC but is (IE there is no leader for it, or its components).
   The function returns NULL_TREE in case a different antic expression
   has to be inserted first.
   This function may also generate expressions that are themselves
   partially or fully redundant.  Those that are will be either made
   fully redundant during the next iteration of insert (for partially
   redundant ones), or eliminated by eliminate (for fully redundant
   ones).  */

static tree
create_expression_by_pieces (basic_block block, pre_expr expr,
			     gimple_seq *stmts, tree type)
{
  tree name;
  tree folded;
  gimple_seq forced_stmts = NULL;
  unsigned int value_id;
  gimple_stmt_iterator gsi;
  tree exprtype = type ? type : get_expr_type (expr);
  pre_expr nameexpr;
  gimple newstmt;

  switch (expr->kind)
    {
      /* We may hit the NAME/CONSTANT case if we have to convert types
	 that value numbering saw through.  */
    case NAME:
      folded = PRE_EXPR_NAME (expr);
      break;
    case CONSTANT:
      folded = PRE_EXPR_CONSTANT (expr);
      break;
    case REFERENCE:
      {
	vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
	folded = create_component_ref_by_pieces (block, ref, stmts);
	if (!folded)
	  return NULL_TREE;
      }
      break;
    case NARY:
      {
	vn_nary_op_t nary = PRE_EXPR_NARY (expr);
	tree *genop = XALLOCAVEC (tree, nary->length);
	unsigned i;
	for (i = 0; i < nary->length; ++i)
	  {
	    genop[i] = find_or_generate_expression (block, nary->op[i], stmts);
	    if (!genop[i])
	      return NULL_TREE;
	    /* Ensure genop[] is properly typed for POINTER_PLUS_EXPR.  It
	       may have conversions stripped.  */
	    if (nary->opcode == POINTER_PLUS_EXPR)
	      {
		if (i == 0)
		  genop[i] = fold_convert (nary->type, genop[i]);
		else if (i == 1)
		  genop[i] = convert_to_ptrofftype (genop[i]);
	      }
	    else
	      genop[i] = fold_convert (TREE_TYPE (nary->op[i]), genop[i]);
	  }
	if (nary->opcode == CONSTRUCTOR)
	  {
	    vec<constructor_elt, va_gc> *elts = NULL;
	    for (i = 0; i < nary->length; ++i)
	      CONSTRUCTOR_APPEND_ELT (elts, NULL_TREE, genop[i]);
	    folded = build_constructor (nary->type, elts);
	  }
	else
	  {
	    switch (nary->length)
	      {
	      case 1:
		folded = fold_build1 (nary->opcode, nary->type,
				      genop[0]);
		break;
	      case 2:
		folded = fold_build2 (nary->opcode, nary->type,
				      genop[0], genop[1]);
		break;
	      case 3:
		folded = fold_build3 (nary->opcode, nary->type,
				      genop[0], genop[1], genop[2]);
		break;
	      default:
		gcc_unreachable ();
	      }
	  }
      }
      break;
    default:
      gcc_unreachable ();
    }

  if (!useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
    folded = fold_convert (exprtype, folded);

  /* Force the generated expression to be a sequence of GIMPLE
     statements.
     We have to call unshare_expr because force_gimple_operand may
     modify the tree we pass to it.  */
  folded = force_gimple_operand (unshare_expr (folded), &forced_stmts,
				 false, NULL);

  /* If we have any intermediate expressions to the value sets, add them
     to the value sets and chain them in the instruction stream.  */
  if (forced_stmts)
    {
      gsi = gsi_start (forced_stmts);
      for (; !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  gimple stmt = gsi_stmt (gsi);
	  tree forcedname = gimple_get_lhs (stmt);
	  pre_expr nameexpr;

	  if (TREE_CODE (forcedname) == SSA_NAME)
	    {
	      bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (forcedname));
	      VN_INFO_GET (forcedname)->valnum = forcedname;
	      VN_INFO (forcedname)->value_id = get_next_value_id ();
	      nameexpr = get_or_alloc_expr_for_name (forcedname);
	      add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
	      bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
	      bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
	    }
	}
      gimple_seq_add_seq (stmts, forced_stmts);
    }

  name = make_temp_ssa_name (exprtype, NULL, "pretmp");
  newstmt = gimple_build_assign (name, folded);
  gimple_set_plf (newstmt, NECESSARY, false);

  gimple_seq_add_stmt (stmts, newstmt);
  bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (name));

  /* Fold the last statement.  */
  gsi = gsi_last (*stmts);
  if (fold_stmt_inplace (&gsi))
    update_stmt (gsi_stmt (gsi));

  /* Add a value number to the temporary.
     The value may already exist in either NEW_SETS, or AVAIL_OUT, because
     we are creating the expression by pieces, and this particular piece of
     the expression may have been represented.  There is no harm in replacing
     here.  */
  value_id = get_expr_value_id (expr);
  VN_INFO_GET (name)->value_id = value_id;
  VN_INFO (name)->valnum = sccvn_valnum_from_value_id (value_id);
  if (VN_INFO (name)->valnum == NULL_TREE)
    VN_INFO (name)->valnum = name;
  gcc_assert (VN_INFO (name)->valnum != NULL_TREE);
  nameexpr = get_or_alloc_expr_for_name (name);
  add_to_value (value_id, nameexpr);
  if (NEW_SETS (block))
    bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
  bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);

  pre_stats.insertions++;
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "Inserted ");
      print_gimple_stmt (dump_file, newstmt, 0, 0);
      fprintf (dump_file, " in predecessor %d\n", block->index);
    }

  return name;
}


/* Returns true if we want to inhibit the insertions of PHI nodes
   for the given EXPR for basic block BB (a member of a loop).
   We want to do this, when we fear that the induction variable we
   create might inhibit vectorization.  */

static bool
inhibit_phi_insertion (basic_block bb, pre_expr expr)
{
  vn_reference_t vr = PRE_EXPR_REFERENCE (expr);
  vec<vn_reference_op_s> ops = vr->operands;
  vn_reference_op_t op;
  unsigned i;

  /* If we aren't going to vectorize we don't inhibit anything.  */
  if (!flag_tree_vectorize)
    return false;

  /* Otherwise we inhibit the insertion when the address of the
     memory reference is a simple induction variable.  In other
     cases the vectorizer won't do anything anyway (either it's
     loop invariant or a complicated expression).  */
  FOR_EACH_VEC_ELT (ops, i, op)
    {
      switch (op->opcode)
	{
	case CALL_EXPR:
	  /* Calls are not a problem.  */
	  return false;

	case ARRAY_REF:
	case ARRAY_RANGE_REF:
	  if (TREE_CODE (op->op0) != SSA_NAME)
	    break;
	  /* Fallthru.  */
	case SSA_NAME:
	  {
	    basic_block defbb = gimple_bb (SSA_NAME_DEF_STMT (op->op0));
	    affine_iv iv;
	    /* Default defs are loop invariant.  */
	    if (!defbb)
	      break;
	    /* Defined outside this loop, also loop invariant.  */
	    if (!flow_bb_inside_loop_p (bb->loop_father, defbb))
	      break;
	    /* If it's a simple induction variable inhibit insertion,
	       the vectorizer might be interested in this one.  */
	    if (simple_iv (bb->loop_father, bb->loop_father,
			   op->op0, &iv, true))
	      return true;
	    /* No simple IV, vectorizer can't do anything, hence no
	       reason to inhibit the transformation for this operand.  */
	    break;
	  }
	default:
	  break;
	}
    }
  return false;
}

/* Insert the to-be-made-available values of expression EXPRNUM for each
   predecessor, stored in AVAIL, into the predecessors of BLOCK, and
   merge the result with a phi node, given the same value number as
   NODE.  Return true if we have inserted new stuff.  */

static bool
insert_into_preds_of_block (basic_block block, unsigned int exprnum,
			    vec<pre_expr> avail)
{
  pre_expr expr = expression_for_id (exprnum);
  pre_expr newphi;
  unsigned int val = get_expr_value_id (expr);
  edge pred;
  bool insertions = false;
  bool nophi = false;
  basic_block bprime;
  pre_expr eprime;
  edge_iterator ei;
  tree type = get_expr_type (expr);
  tree temp;
  gimple phi;

  /* Make sure we aren't creating an induction variable.  */
  if (bb_loop_depth (block) > 0 && EDGE_COUNT (block->preds) == 2)
    {
      bool firstinsideloop = false;
      bool secondinsideloop = false;
      firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
					       EDGE_PRED (block, 0)->src);
      secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
						EDGE_PRED (block, 1)->src);
      /* Induction variables only have one edge inside the loop.  */
      if ((firstinsideloop ^ secondinsideloop)
	  && (expr->kind != REFERENCE
	      || inhibit_phi_insertion (block, expr)))
	{
	  if (dump_file && (dump_flags & TDF_DETAILS))
	    fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
	  nophi = true;
	}
    }

  /* Make the necessary insertions.  */
  FOR_EACH_EDGE (pred, ei, block->preds)
    {
      gimple_seq stmts = NULL;
      tree builtexpr;
      bprime = pred->src;
      eprime = avail[pred->dest_idx];

      if (eprime->kind != NAME && eprime->kind != CONSTANT)
	{
	  builtexpr = create_expression_by_pieces (bprime, eprime,
						   &stmts, type);
	  gcc_assert (!(pred->flags & EDGE_ABNORMAL));
	  gsi_insert_seq_on_edge (pred, stmts);
	  if (!builtexpr)
	    {
	      /* We cannot insert a PHI node if we failed to insert
		 on one edge.  */
	      nophi = true;
	      continue;
	    }
	  avail[pred->dest_idx] = get_or_alloc_expr_for_name (builtexpr);
	  insertions = true;
	}
      else if (eprime->kind == CONSTANT)
	{
	  /* Constants may not have the right type, fold_convert
	     should give us back a constant with the right type.  */
	  tree constant = PRE_EXPR_CONSTANT (eprime);
	  if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
	    {
	      tree builtexpr = fold_convert (type, constant);
	      if (!is_gimple_min_invariant (builtexpr))
		{
		  tree forcedexpr = force_gimple_operand (builtexpr,
							  &stmts, true,
							  NULL);
		  if (!is_gimple_min_invariant (forcedexpr))
		    {
		      if (forcedexpr != builtexpr)
			{
			  VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
			  VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
			}
		      if (stmts)
			{
			  gimple_stmt_iterator gsi;
			  gsi = gsi_start (stmts);
			  for (; !gsi_end_p (gsi); gsi_next (&gsi))
			    {
			      gimple stmt = gsi_stmt (gsi);
			      tree lhs = gimple_get_lhs (stmt);
			      if (TREE_CODE (lhs) == SSA_NAME)
				bitmap_set_bit (inserted_exprs,
						SSA_NAME_VERSION (lhs));
			      gimple_set_plf (stmt, NECESSARY, false);
			    }
			  gsi_insert_seq_on_edge (pred, stmts);
			}
		      avail[pred->dest_idx]
			= get_or_alloc_expr_for_name (forcedexpr);
		    }
		}
	      else
		avail[pred->dest_idx]
		    = get_or_alloc_expr_for_constant (builtexpr);
	    }
	}
      else if (eprime->kind == NAME)
	{
	  /* We may have to do a conversion because our value
	     numbering can look through types in certain cases, but
	     our IL requires all operands of a phi node have the same
	     type.  */
	  tree name = PRE_EXPR_NAME (eprime);
	  if (!useless_type_conversion_p (type, TREE_TYPE (name)))
	    {
	      tree builtexpr;
	      tree forcedexpr;
	      builtexpr = fold_convert (type, name);
	      forcedexpr = force_gimple_operand (builtexpr,
						 &stmts, true,
						 NULL);

	      if (forcedexpr != name)
		{
		  VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
		  VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
		}

	      if (stmts)
		{
		  gimple_stmt_iterator gsi;
		  gsi = gsi_start (stmts);
		  for (; !gsi_end_p (gsi); gsi_next (&gsi))
		    {
		      gimple stmt = gsi_stmt (gsi);
		      tree lhs = gimple_get_lhs (stmt);
		      if (TREE_CODE (lhs) == SSA_NAME)
			bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
		      gimple_set_plf (stmt, NECESSARY, false);
		    }
		  gsi_insert_seq_on_edge (pred, stmts);
		}
	      avail[pred->dest_idx] = get_or_alloc_expr_for_name (forcedexpr);
	    }
	}
    }
  /* If we didn't want a phi node, and we made insertions, we still have
     inserted new stuff, and thus return true.  If we didn't want a phi node,
     and didn't make insertions, we haven't added anything new, so return
     false.  */
  if (nophi && insertions)
    return true;
  else if (nophi && !insertions)
    return false;

  /* Now build a phi for the new variable.  */
  temp = make_temp_ssa_name (type, NULL, "prephitmp");
  phi = create_phi_node (temp, block);

  gimple_set_plf (phi, NECESSARY, false);
  VN_INFO_GET (temp)->value_id = val;
  VN_INFO (temp)->valnum = sccvn_valnum_from_value_id (val);
  if (VN_INFO (temp)->valnum == NULL_TREE)
    VN_INFO (temp)->valnum = temp;
  bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (temp));
  FOR_EACH_EDGE (pred, ei, block->preds)
    {
      pre_expr ae = avail[pred->dest_idx];
      gcc_assert (get_expr_type (ae) == type
		  || useless_type_conversion_p (type, get_expr_type (ae)));
      if (ae->kind == CONSTANT)
	add_phi_arg (phi, unshare_expr (PRE_EXPR_CONSTANT (ae)),
		     pred, UNKNOWN_LOCATION);
      else
	add_phi_arg (phi, PRE_EXPR_NAME (ae), pred, UNKNOWN_LOCATION);
    }

  newphi = get_or_alloc_expr_for_name (temp);
  add_to_value (val, newphi);

  /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
     this insertion, since we test for the existence of this value in PHI_GEN
     before proceeding with the partial redundancy checks in insert_aux.

     The value may exist in AVAIL_OUT, in particular, it could be represented
     by the expression we are trying to eliminate, in which case we want the
     replacement to occur.  If it's not existing in AVAIL_OUT, we want it
     inserted there.

     Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
     this block, because if it did, it would have existed in our dominator's
     AVAIL_OUT, and would have been skipped due to the full redundancy check.
  */

  bitmap_insert_into_set (PHI_GEN (block), newphi);
  bitmap_value_replace_in_set (AVAIL_OUT (block),
			       newphi);
  bitmap_insert_into_set (NEW_SETS (block),
			  newphi);

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "Created phi ");
      print_gimple_stmt (dump_file, phi, 0, 0);
      fprintf (dump_file, " in block %d\n", block->index);
    }
  pre_stats.phis++;
  return true;
}



/* Perform insertion of partially redundant values.
   For BLOCK, do the following:
   1.  Propagate the NEW_SETS of the dominator into the current block.
   If the block has multiple predecessors,
       2a. Iterate over the ANTIC expressions for the block to see if
	   any of them are partially redundant.
       2b. If so, insert them into the necessary predecessors to make
	   the expression fully redundant.
       2c. Insert a new PHI merging the values of the predecessors.
       2d. Insert the new PHI, and the new expressions, into the
	   NEW_SETS set.
   3. Recursively call ourselves on the dominator children of BLOCK.

   Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
   do_regular_insertion and do_partial_insertion.

*/

static bool
do_regular_insertion (basic_block block, basic_block dom)
{
  bool new_stuff = false;
  vec<pre_expr> exprs;
  pre_expr expr;
  vec<pre_expr> avail = vNULL;
  int i;

  exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
  avail.safe_grow (EDGE_COUNT (block->preds));

  FOR_EACH_VEC_ELT (exprs, i, expr)
    {
      if (expr->kind == NARY
	  || expr->kind == REFERENCE)
	{
	  unsigned int val;
	  bool by_some = false;
	  bool cant_insert = false;
	  bool all_same = true;
	  pre_expr first_s = NULL;
	  edge pred;
	  basic_block bprime;
	  pre_expr eprime = NULL;
	  edge_iterator ei;
	  pre_expr edoubleprime = NULL;
	  bool do_insertion = false;

	  val = get_expr_value_id (expr);
	  if (bitmap_set_contains_value (PHI_GEN (block), val))
	    continue;
	  if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
	    {
	      if (dump_file && (dump_flags & TDF_DETAILS))
		fprintf (dump_file, "Found fully redundant value\n");
	      continue;
	    }

	  FOR_EACH_EDGE (pred, ei, block->preds)
	    {
	      unsigned int vprime;

	      /* We should never run insertion for the exit block
	         and so not come across fake pred edges.  */
	      gcc_assert (!(pred->flags & EDGE_FAKE));
	      bprime = pred->src;
	      eprime = phi_translate (expr, ANTIC_IN (block), NULL,
				      bprime, block);

	      /* eprime will generally only be NULL if the
		 value of the expression, translated
		 through the PHI for this predecessor, is
		 undefined.  If that is the case, we can't
		 make the expression fully redundant,
		 because its value is undefined along a
		 predecessor path.  We can thus break out
		 early because it doesn't matter what the
		 rest of the results are.  */
	      if (eprime == NULL)
		{
		  avail[pred->dest_idx] = NULL;
		  cant_insert = true;
		  break;
		}

	      eprime = fully_constant_expression (eprime);
	      vprime = get_expr_value_id (eprime);
	      edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
						 vprime);
	      if (edoubleprime == NULL)
		{
		  avail[pred->dest_idx] = eprime;
		  all_same = false;
		}
	      else
		{
		  avail[pred->dest_idx] = edoubleprime;
		  by_some = true;
		  /* We want to perform insertions to remove a redundancy on
		     a path in the CFG we want to optimize for speed.  */
		  if (optimize_edge_for_speed_p (pred))
		    do_insertion = true;
		  if (first_s == NULL)
		    first_s = edoubleprime;
		  else if (!pre_expr_d::equal (first_s, edoubleprime))
		    all_same = false;
		}
	    }
	  /* If we can insert it, it's not the same value
	     already existing along every predecessor, and
	     it's defined by some predecessor, it is
	     partially redundant.  */
	  if (!cant_insert && !all_same && by_some)
	    {
	      if (!do_insertion)
		{
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    {
		      fprintf (dump_file, "Skipping partial redundancy for "
			       "expression ");
		      print_pre_expr (dump_file, expr);
		      fprintf (dump_file, " (%04d), no redundancy on to be "
			       "optimized for speed edge\n", val);
		    }
		}
	      else if (dbg_cnt (treepre_insert))
		{
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    {
		      fprintf (dump_file, "Found partial redundancy for "
			       "expression ");
		      print_pre_expr (dump_file, expr);
		      fprintf (dump_file, " (%04d)\n",
			       get_expr_value_id (expr));
		    }
		  if (insert_into_preds_of_block (block,
						  get_expression_id (expr),
						  avail))
		    new_stuff = true;
		}
	    }
	  /* If all edges produce the same value and that value is
	     an invariant, then the PHI has the same value on all
	     edges.  Note this.  */
	  else if (!cant_insert && all_same)
	    {
	      gcc_assert (edoubleprime->kind == CONSTANT
			  || edoubleprime->kind == NAME);

	      tree temp = make_temp_ssa_name (get_expr_type (expr),
					      NULL, "pretmp");
	      gimple assign = gimple_build_assign (temp,
						   edoubleprime->kind == CONSTANT ? PRE_EXPR_CONSTANT (edoubleprime) : PRE_EXPR_NAME (edoubleprime));
	      gimple_stmt_iterator gsi = gsi_after_labels (block);
	      gsi_insert_before (&gsi, assign, GSI_NEW_STMT);

	      gimple_set_plf (assign, NECESSARY, false);
	      VN_INFO_GET (temp)->value_id = val;
	      VN_INFO (temp)->valnum = sccvn_valnum_from_value_id (val);
	      if (VN_INFO (temp)->valnum == NULL_TREE)
		VN_INFO (temp)->valnum = temp;
	      bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (temp));
	      pre_expr newe = get_or_alloc_expr_for_name (temp);
	      add_to_value (val, newe);
	      bitmap_value_replace_in_set (AVAIL_OUT (block), newe);
	      bitmap_insert_into_set (NEW_SETS (block), newe);
	    }
	}
    }

  exprs.release ();
  avail.release ();
  return new_stuff;
}


/* Perform insertion for partially anticipatable expressions.  There
   is only one case we will perform insertion for these.  This case is
   if the expression is partially anticipatable, and fully available.
   In this case, we know that putting it earlier will enable us to
   remove the later computation.  */


static bool
do_partial_partial_insertion (basic_block block, basic_block dom)
{
  bool new_stuff = false;
  vec<pre_expr> exprs;
  pre_expr expr;
  vec<pre_expr> avail = vNULL;
  int i;

  exprs = sorted_array_from_bitmap_set (PA_IN (block));
  avail.safe_grow (EDGE_COUNT (block->preds));

  FOR_EACH_VEC_ELT (exprs, i, expr)
    {
      if (expr->kind == NARY
	  || expr->kind == REFERENCE)
	{
	  unsigned int val;
	  bool by_all = true;
	  bool cant_insert = false;
	  edge pred;
	  basic_block bprime;
	  pre_expr eprime = NULL;
	  edge_iterator ei;

	  val = get_expr_value_id (expr);
	  if (bitmap_set_contains_value (PHI_GEN (block), val))
	    continue;
	  if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
	    continue;

	  FOR_EACH_EDGE (pred, ei, block->preds)
	    {
	      unsigned int vprime;
	      pre_expr edoubleprime;

	      /* We should never run insertion for the exit block
	         and so not come across fake pred edges.  */
	      gcc_assert (!(pred->flags & EDGE_FAKE));
	      bprime = pred->src;
	      eprime = phi_translate (expr, ANTIC_IN (block),
				      PA_IN (block),
				      bprime, block);

	      /* eprime will generally only be NULL if the
		 value of the expression, translated
		 through the PHI for this predecessor, is
		 undefined.  If that is the case, we can't
		 make the expression fully redundant,
		 because its value is undefined along a
		 predecessor path.  We can thus break out
		 early because it doesn't matter what the
		 rest of the results are.  */
	      if (eprime == NULL)
		{
		  avail[pred->dest_idx] = NULL;
		  cant_insert = true;
		  break;
		}

	      eprime = fully_constant_expression (eprime);
	      vprime = get_expr_value_id (eprime);
	      edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime), vprime);
	      avail[pred->dest_idx] = edoubleprime;
	      if (edoubleprime == NULL)
		{
		  by_all = false;
		  break;
		}
	    }

	  /* If we can insert it, it's not the same value
	     already existing along every predecessor, and
	     it's defined by some predecessor, it is
	     partially redundant.  */
	  if (!cant_insert && by_all)
	    {
	      edge succ;
	      bool do_insertion = false;

	      /* Insert only if we can remove a later expression on a path
		 that we want to optimize for speed.
		 The phi node that we will be inserting in BLOCK is not free,
		 and inserting it for the sake of !optimize_for_speed successor
		 may cause regressions on the speed path.  */
	      FOR_EACH_EDGE (succ, ei, block->succs)
		{
		  if (bitmap_set_contains_value (PA_IN (succ->dest), val)
		      || bitmap_set_contains_value (ANTIC_IN (succ->dest), val))
		    {
		      if (optimize_edge_for_speed_p (succ))
			do_insertion = true;
		    }
		}

	      if (!do_insertion)
		{
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    {
		      fprintf (dump_file, "Skipping partial partial redundancy "
			       "for expression ");
		      print_pre_expr (dump_file, expr);
		      fprintf (dump_file, " (%04d), not (partially) anticipated "
			       "on any to be optimized for speed edges\n", val);
		    }
		}
	      else if (dbg_cnt (treepre_insert))
		{
		  pre_stats.pa_insert++;
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    {
		      fprintf (dump_file, "Found partial partial redundancy "
			       "for expression ");
		      print_pre_expr (dump_file, expr);
		      fprintf (dump_file, " (%04d)\n",
			       get_expr_value_id (expr));
		    }
		  if (insert_into_preds_of_block (block,
						  get_expression_id (expr),
						  avail))
		    new_stuff = true;
		}	   
	    } 
	}
    }

  exprs.release ();
  avail.release ();
  return new_stuff;
}

static bool
insert_aux (basic_block block)
{
  basic_block son;
  bool new_stuff = false;

  if (block)
    {
      basic_block dom;
      dom = get_immediate_dominator (CDI_DOMINATORS, block);
      if (dom)
	{
	  unsigned i;
	  bitmap_iterator bi;
	  bitmap_set_t newset = NEW_SETS (dom);
	  if (newset)
	    {
	      /* Note that we need to value_replace both NEW_SETS, and
		 AVAIL_OUT. For both the case of NEW_SETS, the value may be
		 represented by some non-simple expression here that we want
		 to replace it with.  */
	      FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
		{
		  pre_expr expr = expression_for_id (i);
		  bitmap_value_replace_in_set (NEW_SETS (block), expr);
		  bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
		}
	    }
	  if (!single_pred_p (block))
	    {
	      new_stuff |= do_regular_insertion (block, dom);
	      if (do_partial_partial)
		new_stuff |= do_partial_partial_insertion (block, dom);
	    }
	}
    }
  for (son = first_dom_son (CDI_DOMINATORS, block);
       son;
       son = next_dom_son (CDI_DOMINATORS, son))
    {
      new_stuff |= insert_aux (son);
    }

  return new_stuff;
}

/* Perform insertion of partially redundant values.  */

static void
insert (void)
{
  bool new_stuff = true;
  basic_block bb;
  int num_iterations = 0;

  FOR_ALL_BB (bb)
    NEW_SETS (bb) = bitmap_set_new ();

  while (new_stuff)
    {
      num_iterations++;
      if (dump_file && dump_flags & TDF_DETAILS)
	fprintf (dump_file, "Starting insert iteration %d\n", num_iterations);
      new_stuff = insert_aux (ENTRY_BLOCK_PTR);

      /* Clear the NEW sets before the next iteration.  We have already
         fully propagated its contents.  */
      if (new_stuff)
	FOR_ALL_BB (bb)
	  bitmap_set_free (NEW_SETS (bb));
    }
  statistics_histogram_event (cfun, "insert iterations", num_iterations);
}


/* Compute the AVAIL set for all basic blocks.

   This function performs value numbering of the statements in each basic
   block.  The AVAIL sets are built from information we glean while doing
   this value numbering, since the AVAIL sets contain only one entry per
   value.

   AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
   AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK].  */

static void
compute_avail (void)
{

  basic_block block, son;
  basic_block *worklist;
  size_t sp = 0;
  unsigned i;

  /* We pretend that default definitions are defined in the entry block.
     This includes function arguments and the static chain decl.  */
  for (i = 1; i < num_ssa_names; ++i)
    {
      tree name = ssa_name (i);
      pre_expr e;
      if (!name
	  || !SSA_NAME_IS_DEFAULT_DEF (name)
	  || has_zero_uses (name)
	  || virtual_operand_p (name))
	continue;

      e = get_or_alloc_expr_for_name (name);
      add_to_value (get_expr_value_id (e), e);
      bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
      bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
    }

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      print_bitmap_set (dump_file, TMP_GEN (ENTRY_BLOCK_PTR),
			"tmp_gen", ENTRY_BLOCK);
      print_bitmap_set (dump_file, AVAIL_OUT (ENTRY_BLOCK_PTR),
			"avail_out", ENTRY_BLOCK);
    }

  /* Allocate the worklist.  */
  worklist = XNEWVEC (basic_block, n_basic_blocks);

  /* Seed the algorithm by putting the dominator children of the entry
     block on the worklist.  */
  for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
       son;
       son = next_dom_son (CDI_DOMINATORS, son))
    worklist[sp++] = son;

  /* Loop until the worklist is empty.  */
  while (sp)
    {
      gimple_stmt_iterator gsi;
      gimple stmt;
      basic_block dom;

      /* Pick a block from the worklist.  */
      block = worklist[--sp];

      /* Initially, the set of available values in BLOCK is that of
	 its immediate dominator.  */
      dom = get_immediate_dominator (CDI_DOMINATORS, block);
      if (dom)
	bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));

      /* Generate values for PHI nodes.  */
      for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  tree result = gimple_phi_result (gsi_stmt (gsi));

	  /* We have no need for virtual phis, as they don't represent
	     actual computations.  */
	  if (virtual_operand_p (result))
	    continue;

	  pre_expr e = get_or_alloc_expr_for_name (result);
	  add_to_value (get_expr_value_id (e), e);
	  bitmap_value_insert_into_set (AVAIL_OUT (block), e);
	  bitmap_insert_into_set (PHI_GEN (block), e);
	}

      BB_MAY_NOTRETURN (block) = 0;

      /* Now compute value numbers and populate value sets with all
	 the expressions computed in BLOCK.  */
      for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  ssa_op_iter iter;
	  tree op;

	  stmt = gsi_stmt (gsi);

	  /* Cache whether the basic-block has any non-visible side-effect
	     or control flow.
	     If this isn't a call or it is the last stmt in the
	     basic-block then the CFG represents things correctly.  */
	  if (is_gimple_call (stmt) && !stmt_ends_bb_p (stmt))
	    {
	      /* Non-looping const functions always return normally.
		 Otherwise the call might not return or have side-effects
		 that forbids hoisting possibly trapping expressions
		 before it.  */
	      int flags = gimple_call_flags (stmt);
	      if (!(flags & ECF_CONST)
		  || (flags & ECF_LOOPING_CONST_OR_PURE))
		BB_MAY_NOTRETURN (block) = 1;
	    }

	  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
	    {
	      pre_expr e = get_or_alloc_expr_for_name (op);

	      add_to_value (get_expr_value_id (e), e);
	      bitmap_insert_into_set (TMP_GEN (block), e);
	      bitmap_value_insert_into_set (AVAIL_OUT (block), e);
	    }

	  if (gimple_has_side_effects (stmt)
	      || stmt_could_throw_p (stmt)
	      || is_gimple_debug (stmt))
	    continue;

	  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
	    {
	      if (ssa_undefined_value_p (op))
		continue;
	      pre_expr e = get_or_alloc_expr_for_name (op);
	      bitmap_value_insert_into_set (EXP_GEN (block), e);
	    }

	  switch (gimple_code (stmt))
	    {
	    case GIMPLE_RETURN:
	      continue;

	    case GIMPLE_CALL:
	      {
		vn_reference_t ref;
		pre_expr result = NULL;
		vec<vn_reference_op_s> ops = vNULL;

		/* We can value number only calls to real functions.  */
		if (gimple_call_internal_p (stmt))
		  continue;

		copy_reference_ops_from_call (stmt, &ops);
		vn_reference_lookup_pieces (gimple_vuse (stmt), 0,
					    gimple_expr_type (stmt),
					    ops, &ref, VN_NOWALK);
		ops.release ();
		if (!ref)
		  continue;

		/* If the value of the call is not invalidated in
		   this block until it is computed, add the expression
		   to EXP_GEN.  */
		if (!gimple_vuse (stmt)
		    || gimple_code
		         (SSA_NAME_DEF_STMT (gimple_vuse (stmt))) == GIMPLE_PHI
		    || gimple_bb (SSA_NAME_DEF_STMT
				    (gimple_vuse (stmt))) != block)
		  {
		    result = (pre_expr) pool_alloc (pre_expr_pool);
		    result->kind = REFERENCE;
		    result->id = 0;
		    PRE_EXPR_REFERENCE (result) = ref;

		    get_or_alloc_expression_id (result);
		    add_to_value (get_expr_value_id (result), result);
		    bitmap_value_insert_into_set (EXP_GEN (block), result);
		  }
		continue;
	      }

	    case GIMPLE_ASSIGN:
	      {
		pre_expr result = NULL;
		switch (vn_get_stmt_kind (stmt))
		  {
		  case VN_NARY:
		    {
		      enum tree_code code = gimple_assign_rhs_code (stmt);
		      vn_nary_op_t nary;

		      /* COND_EXPR and VEC_COND_EXPR are awkward in
			 that they contain an embedded complex expression.
			 Don't even try to shove those through PRE.  */
		      if (code == COND_EXPR
			  || code == VEC_COND_EXPR)
			continue;

		      vn_nary_op_lookup_stmt (stmt, &nary);
		      if (!nary)
			continue;

		      /* If the NARY traps and there was a preceding
		         point in the block that might not return avoid
			 adding the nary to EXP_GEN.  */
		      if (BB_MAY_NOTRETURN (block)
			  && vn_nary_may_trap (nary))
			continue;

		      result = (pre_expr) pool_alloc (pre_expr_pool);
		      result->kind = NARY;
		      result->id = 0;
		      PRE_EXPR_NARY (result) = nary;
		      break;
		    }

		  case VN_REFERENCE:
		    {
		      vn_reference_t ref;
		      vn_reference_lookup (gimple_assign_rhs1 (stmt),
					   gimple_vuse (stmt),
					   VN_WALK, &ref);
		      if (!ref)
			continue;

		      /* If the value of the reference is not invalidated in
			 this block until it is computed, add the expression
			 to EXP_GEN.  */
		      if (gimple_vuse (stmt))
			{
			  gimple def_stmt;
			  bool ok = true;
			  def_stmt = SSA_NAME_DEF_STMT (gimple_vuse (stmt));
			  while (!gimple_nop_p (def_stmt)
				 && gimple_code (def_stmt) != GIMPLE_PHI
				 && gimple_bb (def_stmt) == block)
			    {
			      if (stmt_may_clobber_ref_p
				    (def_stmt, gimple_assign_rhs1 (stmt)))
				{
				  ok = false;
				  break;
				}
			      def_stmt
				= SSA_NAME_DEF_STMT (gimple_vuse (def_stmt));
			    }
			  if (!ok)
			    continue;
			}

		      result = (pre_expr) pool_alloc (pre_expr_pool);
		      result->kind = REFERENCE;
		      result->id = 0;
		      PRE_EXPR_REFERENCE (result) = ref;
		      break;
		    }

		  default:
		    continue;
		  }

		get_or_alloc_expression_id (result);
		add_to_value (get_expr_value_id (result), result);
		bitmap_value_insert_into_set (EXP_GEN (block), result);
		continue;
	      }
	    default:
	      break;
	    }
	}

      if (dump_file && (dump_flags & TDF_DETAILS))
	{
	  print_bitmap_set (dump_file, EXP_GEN (block),
			    "exp_gen", block->index);
	  print_bitmap_set (dump_file, PHI_GEN (block),
			    "phi_gen", block->index);
	  print_bitmap_set (dump_file, TMP_GEN (block),
			    "tmp_gen", block->index);
	  print_bitmap_set (dump_file, AVAIL_OUT (block),
			    "avail_out", block->index);
	}

      /* Put the dominator children of BLOCK on the worklist of blocks
	 to compute available sets for.  */
      for (son = first_dom_son (CDI_DOMINATORS, block);
	   son;
	   son = next_dom_son (CDI_DOMINATORS, son))
	worklist[sp++] = son;
    }

  free (worklist);
}


/* Local state for the eliminate domwalk.  */
static vec<gimple> el_to_remove;
static vec<gimple> el_to_update;
static unsigned int el_todo;
static vec<tree> el_avail;
static vec<tree> el_avail_stack;

/* Return a leader for OP that is available at the current point of the
   eliminate domwalk.  */

static tree
eliminate_avail (tree op)
{
  tree valnum = VN_INFO (op)->valnum;
  if (TREE_CODE (valnum) == SSA_NAME)
    {
      if (SSA_NAME_IS_DEFAULT_DEF (valnum))
	return valnum;
      if (el_avail.length () > SSA_NAME_VERSION (valnum))
	return el_avail[SSA_NAME_VERSION (valnum)];
    }
  else if (is_gimple_min_invariant (valnum))
    return valnum;
  return NULL_TREE;
}

/* At the current point of the eliminate domwalk make OP available.  */

static void
eliminate_push_avail (tree op)
{
  tree valnum = VN_INFO (op)->valnum;
  if (TREE_CODE (valnum) == SSA_NAME)
    {
      if (el_avail.length () <= SSA_NAME_VERSION (valnum))
	el_avail.safe_grow_cleared (SSA_NAME_VERSION (valnum) + 1);
      el_avail[SSA_NAME_VERSION (valnum)] = op;
      el_avail_stack.safe_push (op);
    }
}

/* Insert the expression recorded by SCCVN for VAL at *GSI.  Returns
   the leader for the expression if insertion was successful.  */

static tree
eliminate_insert (gimple_stmt_iterator *gsi, tree val)
{
  tree expr = vn_get_expr_for (val);
  if (!CONVERT_EXPR_P (expr)
      && TREE_CODE (expr) != VIEW_CONVERT_EXPR)
    return NULL_TREE;

  tree op = TREE_OPERAND (expr, 0);
  tree leader = TREE_CODE (op) == SSA_NAME ? eliminate_avail (op) : op;
  if (!leader)
    return NULL_TREE;

  tree res = make_temp_ssa_name (TREE_TYPE (val), NULL, "pretmp");
  gimple tem = gimple_build_assign (res,
				    fold_build1 (TREE_CODE (expr),
						 TREE_TYPE (expr), leader));
  gsi_insert_before (gsi, tem, GSI_SAME_STMT);
  VN_INFO_GET (res)->valnum = val;

  if (TREE_CODE (leader) == SSA_NAME)
    gimple_set_plf (SSA_NAME_DEF_STMT (leader), NECESSARY, true);

  pre_stats.insertions++;
  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "Inserted ");
      print_gimple_stmt (dump_file, tem, 0, 0);
    }

  return res;
}

/* Perform elimination for the basic-block B during the domwalk.  */

static void
eliminate_bb (dom_walk_data *, basic_block b)
{
  gimple_stmt_iterator gsi;
  gimple stmt;

  /* Mark new bb.  */
  el_avail_stack.safe_push (NULL_TREE);

  for (gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
    {
      gimple stmt, phi = gsi_stmt (gsi);
      tree sprime = NULL_TREE, res = PHI_RESULT (phi);
      gimple_stmt_iterator gsi2;

      /* We want to perform redundant PHI elimination.  Do so by
	 replacing the PHI with a single copy if possible.
	 Do not touch inserted, single-argument or virtual PHIs.  */
      if (gimple_phi_num_args (phi) == 1
	  || virtual_operand_p (res))
	{
	  gsi_next (&gsi);
	  continue;
	}

      sprime = eliminate_avail (res);
      if (!sprime
	  || sprime == res)
	{
	  eliminate_push_avail (res);
	  gsi_next (&gsi);
	  continue;
	}
      else if (is_gimple_min_invariant (sprime))
	{
	  if (!useless_type_conversion_p (TREE_TYPE (res),
					  TREE_TYPE (sprime)))
	    sprime = fold_convert (TREE_TYPE (res), sprime);
	}

      if (dump_file && (dump_flags & TDF_DETAILS))
	{
	  fprintf (dump_file, "Replaced redundant PHI node defining ");
	  print_generic_expr (dump_file, res, 0);
	  fprintf (dump_file, " with ");
	  print_generic_expr (dump_file, sprime, 0);
	  fprintf (dump_file, "\n");
	}

      remove_phi_node (&gsi, false);

      if (inserted_exprs
	  && !bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res))
	  && TREE_CODE (sprime) == SSA_NAME)
	gimple_set_plf (SSA_NAME_DEF_STMT (sprime), NECESSARY, true);

      if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
	sprime = fold_convert (TREE_TYPE (res), sprime);
      stmt = gimple_build_assign (res, sprime);
      SSA_NAME_DEF_STMT (res) = stmt;
      gimple_set_plf (stmt, NECESSARY, gimple_plf (phi, NECESSARY));

      gsi2 = gsi_after_labels (b);
      gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
      /* Queue the copy for eventual removal.  */
      el_to_remove.safe_push (stmt);
      /* If we inserted this PHI node ourself, it's not an elimination.  */
      if (inserted_exprs
	  && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res)))
	pre_stats.phis--;
      else
	pre_stats.eliminations++;
    }

  for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      tree lhs = NULL_TREE;
      tree rhs = NULL_TREE;

      stmt = gsi_stmt (gsi);

      if (gimple_has_lhs (stmt))
	lhs = gimple_get_lhs (stmt);

      if (gimple_assign_single_p (stmt))
	rhs = gimple_assign_rhs1 (stmt);

      /* Lookup the RHS of the expression, see if we have an
	 available computation for it.  If so, replace the RHS with
	 the available computation.  */
      if (gimple_has_lhs (stmt)
	  && TREE_CODE (lhs) == SSA_NAME
	  && !gimple_has_volatile_ops  (stmt))
	{
	  tree sprime;
	  gimple orig_stmt = stmt;

	  sprime = eliminate_avail (lhs);
	  /* If there is no usable leader mark lhs as leader for its value.  */
	  if (!sprime)
	    eliminate_push_avail (lhs);

	  /* See PR43491.  Do not replace a global register variable when
	     it is a the RHS of an assignment.  Do replace local register
	     variables since gcc does not guarantee a local variable will
	     be allocated in register.
	     Do not perform copy propagation or undo constant propagation.  */
	  if (gimple_assign_single_p (stmt)
	      && (TREE_CODE (rhs) == SSA_NAME
		  || is_gimple_min_invariant (rhs)
		  || (TREE_CODE (rhs) == VAR_DECL
		      && is_global_var (rhs)
		      && DECL_HARD_REGISTER (rhs))))
	    continue;

	  if (!sprime)
	    {
	      /* If there is no existing usable leader but SCCVN thinks
		 it has an expression it wants to use as replacement,
		 insert that.  */
	      tree val = VN_INFO (lhs)->valnum;
	      if (val != VN_TOP
		  && TREE_CODE (val) == SSA_NAME
		  && VN_INFO (val)->needs_insertion
		  && VN_INFO (val)->expr != NULL_TREE
		  && (sprime = eliminate_insert (&gsi, val)) != NULL_TREE)
		eliminate_push_avail (sprime);
	    }
	  else if (is_gimple_min_invariant (sprime))
	    {
	      /* If there is no existing leader but SCCVN knows this
		 value is constant, use that constant.  */
	      if (!useless_type_conversion_p (TREE_TYPE (lhs),
					      TREE_TYPE (sprime)))
		sprime = fold_convert (TREE_TYPE (lhs), sprime);

	      if (dump_file && (dump_flags & TDF_DETAILS))
		{
		  fprintf (dump_file, "Replaced ");
		  print_gimple_expr (dump_file, stmt, 0, 0);
		  fprintf (dump_file, " with ");
		  print_generic_expr (dump_file, sprime, 0);
		  fprintf (dump_file, " in ");
		  print_gimple_stmt (dump_file, stmt, 0, 0);
		}
	      pre_stats.eliminations++;
	      propagate_tree_value_into_stmt (&gsi, sprime);
	      stmt = gsi_stmt (gsi);
	      update_stmt (stmt);

	      /* If we removed EH side-effects from the statement, clean
		 its EH information.  */
	      if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
		{
		  bitmap_set_bit (need_eh_cleanup,
				  gimple_bb (stmt)->index);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "  Removed EH side-effects.\n");
		}
	      continue;
	    }

	  if (sprime
	      && sprime != lhs
	      && (rhs == NULL_TREE
		  || TREE_CODE (rhs) != SSA_NAME
		  || may_propagate_copy (rhs, sprime)))
	    {
	      bool can_make_abnormal_goto
		  = is_gimple_call (stmt)
		  && stmt_can_make_abnormal_goto (stmt);

	      gcc_assert (sprime != rhs);

	      if (dump_file && (dump_flags & TDF_DETAILS))
		{
		  fprintf (dump_file, "Replaced ");
		  print_gimple_expr (dump_file, stmt, 0, 0);
		  fprintf (dump_file, " with ");
		  print_generic_expr (dump_file, sprime, 0);
		  fprintf (dump_file, " in ");
		  print_gimple_stmt (dump_file, stmt, 0, 0);
		}

	      if (TREE_CODE (sprime) == SSA_NAME)
		gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
				NECESSARY, true);
	      /* We need to make sure the new and old types actually match,
		 which may require adding a simple cast, which fold_convert
		 will do for us.  */
	      if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
		  && !useless_type_conversion_p (gimple_expr_type (stmt),
						 TREE_TYPE (sprime)))
		sprime = fold_convert (gimple_expr_type (stmt), sprime);

	      pre_stats.eliminations++;
	      propagate_tree_value_into_stmt (&gsi, sprime);
	      stmt = gsi_stmt (gsi);
	      update_stmt (stmt);

	      /* If we removed EH side-effects from the statement, clean
		 its EH information.  */
	      if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
		{
		  bitmap_set_bit (need_eh_cleanup,
				  gimple_bb (stmt)->index);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "  Removed EH side-effects.\n");
		}

	      /* Likewise for AB side-effects.  */
	      if (can_make_abnormal_goto
		  && !stmt_can_make_abnormal_goto (stmt))
		{
		  bitmap_set_bit (need_ab_cleanup,
				  gimple_bb (stmt)->index);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "  Removed AB side-effects.\n");
		}
	    }
	}
      /* If the statement is a scalar store, see if the expression
	 has the same value number as its rhs.  If so, the store is
	 dead.  */
      else if (gimple_assign_single_p (stmt)
	       && !gimple_has_volatile_ops (stmt)
	       && !is_gimple_reg (gimple_assign_lhs (stmt))
	       && (TREE_CODE (rhs) == SSA_NAME
		   || is_gimple_min_invariant (rhs)))
	{
	  tree val;
	  val = vn_reference_lookup (gimple_assign_lhs (stmt),
				     gimple_vuse (stmt), VN_WALK, NULL);
	  if (TREE_CODE (rhs) == SSA_NAME)
	    rhs = VN_INFO (rhs)->valnum;
	  if (val
	      && operand_equal_p (val, rhs, 0))
	    {
	      if (dump_file && (dump_flags & TDF_DETAILS))
		{
		  fprintf (dump_file, "Deleted redundant store ");
		  print_gimple_stmt (dump_file, stmt, 0, 0);
		}

	      /* Queue stmt for removal.  */
	      el_to_remove.safe_push (stmt);
	    }
	}
      /* Visit COND_EXPRs and fold the comparison with the
	 available value-numbers.  */
      else if (gimple_code (stmt) == GIMPLE_COND)
	{
	  tree op0 = gimple_cond_lhs (stmt);
	  tree op1 = gimple_cond_rhs (stmt);
	  tree result;

	  if (TREE_CODE (op0) == SSA_NAME)
	    op0 = VN_INFO (op0)->valnum;
	  if (TREE_CODE (op1) == SSA_NAME)
	    op1 = VN_INFO (op1)->valnum;
	  result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
				op0, op1);
	  if (result && TREE_CODE (result) == INTEGER_CST)
	    {
	      if (integer_zerop (result))
		gimple_cond_make_false (stmt);
	      else
		gimple_cond_make_true (stmt);
	      update_stmt (stmt);
	      el_todo = TODO_cleanup_cfg;
	    }
	}
      /* Visit indirect calls and turn them into direct calls if
	 possible.  */
      if (is_gimple_call (stmt))
	{
	  tree orig_fn = gimple_call_fn (stmt);
	  tree fn;
	  if (!orig_fn)
	    continue;
	  if (TREE_CODE (orig_fn) == SSA_NAME)
	    fn = VN_INFO (orig_fn)->valnum;
	  else if (TREE_CODE (orig_fn) == OBJ_TYPE_REF
		   && TREE_CODE (OBJ_TYPE_REF_EXPR (orig_fn)) == SSA_NAME)
	    fn = VN_INFO (OBJ_TYPE_REF_EXPR (orig_fn))->valnum;
	  else
	    continue;
	  if (gimple_call_addr_fndecl (fn) != NULL_TREE
	      && useless_type_conversion_p (TREE_TYPE (orig_fn),
					    TREE_TYPE (fn)))
	    {
	      bool can_make_abnormal_goto
		  = stmt_can_make_abnormal_goto (stmt);
	      bool was_noreturn = gimple_call_noreturn_p (stmt);

	      if (dump_file && (dump_flags & TDF_DETAILS))
		{
		  fprintf (dump_file, "Replacing call target with ");
		  print_generic_expr (dump_file, fn, 0);
		  fprintf (dump_file, " in ");
		  print_gimple_stmt (dump_file, stmt, 0, 0);
		}

	      gimple_call_set_fn (stmt, fn);
	      el_to_update.safe_push (stmt);

	      /* When changing a call into a noreturn call, cfg cleanup
		 is needed to fix up the noreturn call.  */
	      if (!was_noreturn && gimple_call_noreturn_p (stmt))
		el_todo |= TODO_cleanup_cfg;

	      /* If we removed EH side-effects from the statement, clean
		 its EH information.  */
	      if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
		{
		  bitmap_set_bit (need_eh_cleanup,
				  gimple_bb (stmt)->index);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "  Removed EH side-effects.\n");
		}

	      /* Likewise for AB side-effects.  */
	      if (can_make_abnormal_goto
		  && !stmt_can_make_abnormal_goto (stmt))
		{
		  bitmap_set_bit (need_ab_cleanup,
				  gimple_bb (stmt)->index);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "  Removed AB side-effects.\n");
		}

	      /* Changing an indirect call to a direct call may
		 have exposed different semantics.  This may
		 require an SSA update.  */
	      el_todo |= TODO_update_ssa_only_virtuals;
	    }
	}
    }
}

/* Make no longer available leaders no longer available.  */

static void
eliminate_leave_block (dom_walk_data *, basic_block)
{
  tree entry;
  while ((entry = el_avail_stack.pop ()) != NULL_TREE)
    el_avail[SSA_NAME_VERSION (VN_INFO (entry)->valnum)] = NULL_TREE;
}

/* Eliminate fully redundant computations.  */

static unsigned int
eliminate (void)
{
  struct dom_walk_data walk_data;
  gimple_stmt_iterator gsi;
  gimple stmt;
  unsigned i;

  need_eh_cleanup = BITMAP_ALLOC (NULL);
  need_ab_cleanup = BITMAP_ALLOC (NULL);

  el_to_remove.create (0);
  el_to_update.create (0);
  el_todo = 0;
  el_avail.create (0);
  el_avail_stack.create (0);

  walk_data.dom_direction = CDI_DOMINATORS;
  walk_data.initialize_block_local_data = NULL;
  walk_data.before_dom_children = eliminate_bb;
  walk_data.after_dom_children = eliminate_leave_block;
  walk_data.global_data = NULL;
  walk_data.block_local_data_size = 0;
  init_walk_dominator_tree (&walk_data);
  walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
  fini_walk_dominator_tree (&walk_data);

  el_avail.release ();
  el_avail_stack.release ();

  /* We cannot remove stmts during BB walk, especially not release SSA
     names there as this confuses the VN machinery.  The stmts ending
     up in el_to_remove are either stores or simple copies.  */
  FOR_EACH_VEC_ELT (el_to_remove, i, stmt)
    {
      tree lhs = gimple_assign_lhs (stmt);
      tree rhs = gimple_assign_rhs1 (stmt);
      use_operand_p use_p;
      gimple use_stmt;

      /* If there is a single use only, propagate the equivalency
	 instead of keeping the copy.  */
      if (TREE_CODE (lhs) == SSA_NAME
	  && TREE_CODE (rhs) == SSA_NAME
	  && single_imm_use (lhs, &use_p, &use_stmt)
	  && may_propagate_copy (USE_FROM_PTR (use_p), rhs))
	{
	  SET_USE (use_p, rhs);
	  update_stmt (use_stmt);
	  if (inserted_exprs
	      && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (lhs))
	      && TREE_CODE (rhs) == SSA_NAME)
	    gimple_set_plf (SSA_NAME_DEF_STMT (rhs), NECESSARY, true);
	}

      /* If this is a store or a now unused copy, remove it.  */
      if (TREE_CODE (lhs) != SSA_NAME
	  || has_zero_uses (lhs))
	{
	  basic_block bb = gimple_bb (stmt);
	  gsi = gsi_for_stmt (stmt);
	  unlink_stmt_vdef (stmt);
	  if (gsi_remove (&gsi, true))
	    bitmap_set_bit (need_eh_cleanup, bb->index);
	  if (inserted_exprs
	      && TREE_CODE (lhs) == SSA_NAME)
	    bitmap_clear_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
	  release_defs (stmt);
	}
    }
  el_to_remove.release ();

  /* We cannot update call statements with virtual operands during
     SSA walk.  This might remove them which in turn makes our
     VN lattice invalid.  */
  FOR_EACH_VEC_ELT (el_to_update, i, stmt)
    update_stmt (stmt);
  el_to_update.release ();

  return el_todo;
}

/* Perform CFG cleanups made necessary by elimination.  */

static unsigned 
fini_eliminate (void)
{
  bool do_eh_cleanup = !bitmap_empty_p (need_eh_cleanup);
  bool do_ab_cleanup = !bitmap_empty_p (need_ab_cleanup);

  if (do_eh_cleanup)
    gimple_purge_all_dead_eh_edges (need_eh_cleanup);

  if (do_ab_cleanup)
    gimple_purge_all_dead_abnormal_call_edges (need_ab_cleanup);

  BITMAP_FREE (need_eh_cleanup);
  BITMAP_FREE (need_ab_cleanup);

  if (do_eh_cleanup || do_ab_cleanup)
    return TODO_cleanup_cfg;
  return 0;
}

/* Borrow a bit of tree-ssa-dce.c for the moment.
   XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
   this may be a bit faster, and we may want critical edges kept split.  */

/* If OP's defining statement has not already been determined to be necessary,
   mark that statement necessary. Return the stmt, if it is newly
   necessary.  */

static inline gimple
mark_operand_necessary (tree op)
{
  gimple stmt;

  gcc_assert (op);

  if (TREE_CODE (op) != SSA_NAME)
    return NULL;

  stmt = SSA_NAME_DEF_STMT (op);
  gcc_assert (stmt);

  if (gimple_plf (stmt, NECESSARY)
      || gimple_nop_p (stmt))
    return NULL;

  gimple_set_plf (stmt, NECESSARY, true);
  return stmt;
}

/* Because we don't follow exactly the standard PRE algorithm, and decide not
   to insert PHI nodes sometimes, and because value numbering of casts isn't
   perfect, we sometimes end up inserting dead code.   This simple DCE-like
   pass removes any insertions we made that weren't actually used.  */

static void
remove_dead_inserted_code (void)
{
  bitmap worklist;
  unsigned i;
  bitmap_iterator bi;
  gimple t;

  worklist = BITMAP_ALLOC (NULL);
  EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
    {
      t = SSA_NAME_DEF_STMT (ssa_name (i));
      if (gimple_plf (t, NECESSARY))
	bitmap_set_bit (worklist, i);
    }
  while (!bitmap_empty_p (worklist))
    {
      i = bitmap_first_set_bit (worklist);
      bitmap_clear_bit (worklist, i);
      t = SSA_NAME_DEF_STMT (ssa_name (i));

      /* PHI nodes are somewhat special in that each PHI alternative has
	 data and control dependencies.  All the statements feeding the
	 PHI node's arguments are always necessary. */
      if (gimple_code (t) == GIMPLE_PHI)
	{
	  unsigned k;

	  for (k = 0; k < gimple_phi_num_args (t); k++)
	    {
	      tree arg = PHI_ARG_DEF (t, k);
	      if (TREE_CODE (arg) == SSA_NAME)
		{
		  gimple n = mark_operand_necessary (arg);
		  if (n)
		    bitmap_set_bit (worklist, SSA_NAME_VERSION (arg));
		}
	    }
	}
      else
	{
	  /* Propagate through the operands.  Examine all the USE, VUSE and
	     VDEF operands in this statement.  Mark all the statements
	     which feed this statement's uses as necessary.  */
	  ssa_op_iter iter;
	  tree use;

	  /* The operands of VDEF expressions are also needed as they
	     represent potential definitions that may reach this
	     statement (VDEF operands allow us to follow def-def
	     links).  */

	  FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
	    {
	      gimple n = mark_operand_necessary (use);
	      if (n)
		bitmap_set_bit (worklist, SSA_NAME_VERSION (use));
	    }
	}
    }

  EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
    {
      t = SSA_NAME_DEF_STMT (ssa_name (i));
      if (!gimple_plf (t, NECESSARY))
	{
	  gimple_stmt_iterator gsi;

	  if (dump_file && (dump_flags & TDF_DETAILS))
	    {
	      fprintf (dump_file, "Removing unnecessary insertion:");
	      print_gimple_stmt (dump_file, t, 0, 0);
	    }

	  gsi = gsi_for_stmt (t);
	  if (gimple_code (t) == GIMPLE_PHI)
	    remove_phi_node (&gsi, true);
	  else
	    {
	      gsi_remove (&gsi, true);
	      release_defs (t);
	    }
	}
    }
  BITMAP_FREE (worklist);
}


/* Initialize data structures used by PRE.  */

static void
init_pre (void)
{
  basic_block bb;

  next_expression_id = 1;
  expressions.create (0);
  expressions.safe_push (NULL);
  value_expressions.create (get_max_value_id () + 1);
  value_expressions.safe_grow_cleared (get_max_value_id() + 1);
  name_to_id.create (0);

  inserted_exprs = BITMAP_ALLOC (NULL);

  connect_infinite_loops_to_exit ();
  memset (&pre_stats, 0, sizeof (pre_stats));

  postorder = XNEWVEC (int, n_basic_blocks);
  postorder_num = inverted_post_order_compute (postorder);

  alloc_aux_for_blocks (sizeof (struct bb_bitmap_sets));

  calculate_dominance_info (CDI_POST_DOMINATORS);
  calculate_dominance_info (CDI_DOMINATORS);

  bitmap_obstack_initialize (&grand_bitmap_obstack);
  phi_translate_table.create (5110);
  expression_to_id.create (num_ssa_names * 3);
  bitmap_set_pool = create_alloc_pool ("Bitmap sets",
				       sizeof (struct bitmap_set), 30);
  pre_expr_pool = create_alloc_pool ("pre_expr nodes",
				     sizeof (struct pre_expr_d), 30);
  FOR_ALL_BB (bb)
    {
      EXP_GEN (bb) = bitmap_set_new ();
      PHI_GEN (bb) = bitmap_set_new ();
      TMP_GEN (bb) = bitmap_set_new ();
      AVAIL_OUT (bb) = bitmap_set_new ();
    }
}


/* Deallocate data structures used by PRE.  */

static void
fini_pre ()
{
  free (postorder);
  value_expressions.release ();
  BITMAP_FREE (inserted_exprs);
  bitmap_obstack_release (&grand_bitmap_obstack);
  free_alloc_pool (bitmap_set_pool);
  free_alloc_pool (pre_expr_pool);
  phi_translate_table.dispose ();
  expression_to_id.dispose ();
  name_to_id.release ();

  free_aux_for_blocks ();

  free_dominance_info (CDI_POST_DOMINATORS);
}

/* Gate and execute functions for PRE.  */

static unsigned int
do_pre (void)
{
  unsigned int todo = 0;

  do_partial_partial =
    flag_tree_partial_pre && optimize_function_for_speed_p (cfun);

  /* This has to happen before SCCVN runs because
     loop_optimizer_init may create new phis, etc.  */
  loop_optimizer_init (LOOPS_NORMAL);

  if (!run_scc_vn (VN_WALK))
    {
      loop_optimizer_finalize ();
      return 0;
    }

  init_pre ();
  scev_initialize ();

  /* Collect and value number expressions computed in each basic block.  */
  compute_avail ();

  /* Insert can get quite slow on an incredibly large number of basic
     blocks due to some quadratic behavior.  Until this behavior is
     fixed, don't run it when he have an incredibly large number of
     bb's.  If we aren't going to run insert, there is no point in
     computing ANTIC, either, even though it's plenty fast.  */
  if (n_basic_blocks < 4000)
    {
      compute_antic ();
      insert ();
    }

  /* Make sure to remove fake edges before committing our inserts.
     This makes sure we don't end up with extra critical edges that
     we would need to split.  */
  remove_fake_exit_edges ();
  gsi_commit_edge_inserts ();

  /* Remove all the redundant expressions.  */
  todo |= eliminate ();

  statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
  statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
  statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
  statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);

  clear_expression_ids ();
  remove_dead_inserted_code ();
  todo |= TODO_verify_flow;

  scev_finalize ();
  fini_pre ();
  todo |= fini_eliminate ();
  loop_optimizer_finalize ();

  /* TODO: tail_merge_optimize may merge all predecessors of a block, in which
     case we can merge the block with the remaining predecessor of the block.
     It should either:
     - call merge_blocks after each tail merge iteration
     - call merge_blocks after all tail merge iterations
     - mark TODO_cleanup_cfg when necessary
     - share the cfg cleanup with fini_pre.  */
  todo |= tail_merge_optimize (todo);

  free_scc_vn ();

  /* Tail merging invalidates the virtual SSA web, together with
     cfg-cleanup opportunities exposed by PRE this will wreck the
     SSA updating machinery.  So make sure to run update-ssa
     manually, before eventually scheduling cfg-cleanup as part of
     the todo.  */
  update_ssa (TODO_update_ssa_only_virtuals);

  return todo;
}

static bool
gate_pre (void)
{
  return flag_tree_pre != 0;
}

struct gimple_opt_pass pass_pre =
{
 {
  GIMPLE_PASS,
  "pre",				/* name */
  OPTGROUP_NONE,                        /* optinfo_flags */
  gate_pre,				/* gate */
  do_pre,				/* execute */
  NULL,					/* sub */
  NULL,					/* next */
  0,					/* static_pass_number */
  TV_TREE_PRE,				/* tv_id */
  PROP_no_crit_edges | PROP_cfg
    | PROP_ssa,				/* properties_required */
  0,					/* properties_provided */
  0,					/* properties_destroyed */
  TODO_rebuild_alias,			/* todo_flags_start */
  TODO_ggc_collect | TODO_verify_ssa	/* todo_flags_finish */
 }
};


/* Gate and execute functions for FRE.  */

static unsigned int
execute_fre (void)
{
  unsigned int todo = 0;

  if (!run_scc_vn (VN_WALKREWRITE))
    return 0;

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

  /* Remove all the redundant expressions.  */
  todo |= eliminate ();

  todo |= fini_eliminate ();

  free_scc_vn ();

  statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
  statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);

  return todo;
}

static bool
gate_fre (void)
{
  return flag_tree_fre != 0;
}

struct gimple_opt_pass pass_fre =
{
 {
  GIMPLE_PASS,
  "fre",				/* name */
  OPTGROUP_NONE,                        /* optinfo_flags */
  gate_fre,				/* gate */
  execute_fre,				/* execute */
  NULL,					/* sub */
  NULL,					/* next */
  0,					/* static_pass_number */
  TV_TREE_FRE,				/* tv_id */
  PROP_cfg | PROP_ssa,			/* properties_required */
  0,					/* properties_provided */
  0,					/* properties_destroyed */
  0,					/* todo_flags_start */
  TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
 }
};