summaryrefslogtreecommitdiff
path: root/gcc/stmt.c
blob: bada27cea0451e1d53eb627758d11d6b3e18619d (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
/* Expands front end tree to back end RTL for GCC
   Copyright (C) 1987-2013 Free Software Foundation, Inc.

This file is part of GCC.

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

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

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

/* This file handles the generation of rtl code from tree structure
   above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
   The functions whose names start with `expand_' are called by the
   expander to generate RTL instructions for various kinds of constructs.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"

#include "rtl.h"
#include "hard-reg-set.h"
#include "tree.h"
#include "tm_p.h"
#include "flags.h"
#include "except.h"
#include "function.h"
#include "insn-config.h"
#include "expr.h"
#include "libfuncs.h"
#include "recog.h"
#include "machmode.h"
#include "diagnostic-core.h"
#include "output.h"
#include "ggc.h"
#include "langhooks.h"
#include "predict.h"
#include "optabs.h"
#include "target.h"
#include "gimple.h"
#include "regs.h"
#include "alloc-pool.h"
#include "pretty-print.h"
#include "pointer-set.h"
#include "params.h"
#include "dumpfile.h"


/* Functions and data structures for expanding case statements.  */

/* Case label structure, used to hold info on labels within case
   statements.  We handle "range" labels; for a single-value label
   as in C, the high and low limits are the same.

   We start with a vector of case nodes sorted in ascending order, and
   the default label as the last element in the vector.  Before expanding
   to RTL, we transform this vector into a list linked via the RIGHT
   fields in the case_node struct.  Nodes with higher case values are
   later in the list.

   Switch statements can be output in three forms.  A branch table is
   used if there are more than a few labels and the labels are dense
   within the range between the smallest and largest case value.  If a
   branch table is used, no further manipulations are done with the case
   node chain.

   The alternative to the use of a branch table is to generate a series
   of compare and jump insns.  When that is done, we use the LEFT, RIGHT,
   and PARENT fields to hold a binary tree.  Initially the tree is
   totally unbalanced, with everything on the right.  We balance the tree
   with nodes on the left having lower case values than the parent
   and nodes on the right having higher values.  We then output the tree
   in order.

   For very small, suitable switch statements, we can generate a series
   of simple bit test and branches instead.  */

struct case_node
{
  struct case_node	*left;	/* Left son in binary tree */
  struct case_node	*right;	/* Right son in binary tree; also node chain */
  struct case_node	*parent; /* Parent of node in binary tree */
  tree			low;	/* Lowest index value for this label */
  tree			high;	/* Highest index value for this label */
  tree			code_label; /* Label to jump to when node matches */
  int                   prob; /* Probability of taking this case.  */
  /* Probability of reaching subtree rooted at this node */
  int                   subtree_prob;
};

typedef struct case_node case_node;
typedef struct case_node *case_node_ptr;

extern basic_block label_to_block_fn (struct function *, tree);

static int n_occurrences (int, const char *);
static bool tree_conflicts_with_clobbers_p (tree, HARD_REG_SET *);
static void expand_nl_goto_receiver (void);
static bool check_operand_nalternatives (tree, tree);
static bool check_unique_operand_names (tree, tree, tree);
static char *resolve_operand_name_1 (char *, tree, tree, tree);
static void expand_null_return_1 (void);
static void expand_value_return (rtx);
static void balance_case_nodes (case_node_ptr *, case_node_ptr);
static int node_has_low_bound (case_node_ptr, tree);
static int node_has_high_bound (case_node_ptr, tree);
static int node_is_bounded (case_node_ptr, tree);
static void emit_case_nodes (rtx, case_node_ptr, rtx, int, tree);

/* Return the rtx-label that corresponds to a LABEL_DECL,
   creating it if necessary.  */

rtx
label_rtx (tree label)
{
  gcc_assert (TREE_CODE (label) == LABEL_DECL);

  if (!DECL_RTL_SET_P (label))
    {
      rtx r = gen_label_rtx ();
      SET_DECL_RTL (label, r);
      if (FORCED_LABEL (label) || DECL_NONLOCAL (label))
	LABEL_PRESERVE_P (r) = 1;
    }

  return DECL_RTL (label);
}

/* As above, but also put it on the forced-reference list of the
   function that contains it.  */
rtx
force_label_rtx (tree label)
{
  rtx ref = label_rtx (label);
  tree function = decl_function_context (label);

  gcc_assert (function);

  forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref, forced_labels);
  return ref;
}

/* Add an unconditional jump to LABEL as the next sequential instruction.  */

void
emit_jump (rtx label)
{
  do_pending_stack_adjust ();
  emit_jump_insn (gen_jump (label));
  emit_barrier ();
}

/* Emit code to jump to the address
   specified by the pointer expression EXP.  */

void
expand_computed_goto (tree exp)
{
  rtx x = expand_normal (exp);

  x = convert_memory_address (Pmode, x);

  do_pending_stack_adjust ();
  emit_indirect_jump (x);
}

/* Handle goto statements and the labels that they can go to.  */

/* Specify the location in the RTL code of a label LABEL,
   which is a LABEL_DECL tree node.

   This is used for the kind of label that the user can jump to with a
   goto statement, and for alternatives of a switch or case statement.
   RTL labels generated for loops and conditionals don't go through here;
   they are generated directly at the RTL level, by other functions below.

   Note that this has nothing to do with defining label *names*.
   Languages vary in how they do that and what that even means.  */

void
expand_label (tree label)
{
  rtx label_r = label_rtx (label);

  do_pending_stack_adjust ();
  emit_label (label_r);
  if (DECL_NAME (label))
    LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));

  if (DECL_NONLOCAL (label))
    {
      expand_nl_goto_receiver ();
      nonlocal_goto_handler_labels
	= gen_rtx_EXPR_LIST (VOIDmode, label_r,
			     nonlocal_goto_handler_labels);
    }

  if (FORCED_LABEL (label))
    forced_labels = gen_rtx_EXPR_LIST (VOIDmode, label_r, forced_labels);

  if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
    maybe_set_first_label_num (label_r);
}

/* Generate RTL code for a `goto' statement with target label LABEL.
   LABEL should be a LABEL_DECL tree node that was or will later be
   defined with `expand_label'.  */

void
expand_goto (tree label)
{
#ifdef ENABLE_CHECKING
  /* Check for a nonlocal goto to a containing function.  Should have
     gotten translated to __builtin_nonlocal_goto.  */
  tree context = decl_function_context (label);
  gcc_assert (!context || context == current_function_decl);
#endif

  emit_jump (label_rtx (label));
}

/* Return the number of times character C occurs in string S.  */
static int
n_occurrences (int c, const char *s)
{
  int n = 0;
  while (*s)
    n += (*s++ == c);
  return n;
}

/* Generate RTL for an asm statement (explicit assembler code).
   STRING is a STRING_CST node containing the assembler code text,
   or an ADDR_EXPR containing a STRING_CST.  VOL nonzero means the
   insn is volatile; don't optimize it.  */

static void
expand_asm_loc (tree string, int vol, location_t locus)
{
  rtx body;

  if (TREE_CODE (string) == ADDR_EXPR)
    string = TREE_OPERAND (string, 0);

  body = gen_rtx_ASM_INPUT_loc (VOIDmode,
				ggc_strdup (TREE_STRING_POINTER (string)),
				locus);

  MEM_VOLATILE_P (body) = vol;

  emit_insn (body);
}

/* Parse the output constraint pointed to by *CONSTRAINT_P.  It is the
   OPERAND_NUMth output operand, indexed from zero.  There are NINPUTS
   inputs and NOUTPUTS outputs to this extended-asm.  Upon return,
   *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
   memory operand.  Similarly, *ALLOWS_REG will be TRUE iff the
   constraint allows the use of a register operand.  And, *IS_INOUT
   will be true if the operand is read-write, i.e., if it is used as
   an input as well as an output.  If *CONSTRAINT_P is not in
   canonical form, it will be made canonical.  (Note that `+' will be
   replaced with `=' as part of this process.)

   Returns TRUE if all went well; FALSE if an error occurred.  */

bool
parse_output_constraint (const char **constraint_p, int operand_num,
			 int ninputs, int noutputs, bool *allows_mem,
			 bool *allows_reg, bool *is_inout)
{
  const char *constraint = *constraint_p;
  const char *p;

  /* Assume the constraint doesn't allow the use of either a register
     or memory.  */
  *allows_mem = false;
  *allows_reg = false;

  /* Allow the `=' or `+' to not be at the beginning of the string,
     since it wasn't explicitly documented that way, and there is a
     large body of code that puts it last.  Swap the character to
     the front, so as not to uglify any place else.  */
  p = strchr (constraint, '=');
  if (!p)
    p = strchr (constraint, '+');

  /* If the string doesn't contain an `=', issue an error
     message.  */
  if (!p)
    {
      error ("output operand constraint lacks %<=%>");
      return false;
    }

  /* If the constraint begins with `+', then the operand is both read
     from and written to.  */
  *is_inout = (*p == '+');

  /* Canonicalize the output constraint so that it begins with `='.  */
  if (p != constraint || *is_inout)
    {
      char *buf;
      size_t c_len = strlen (constraint);

      if (p != constraint)
	warning (0, "output constraint %qc for operand %d "
		 "is not at the beginning",
		 *p, operand_num);

      /* Make a copy of the constraint.  */
      buf = XALLOCAVEC (char, c_len + 1);
      strcpy (buf, constraint);
      /* Swap the first character and the `=' or `+'.  */
      buf[p - constraint] = buf[0];
      /* Make sure the first character is an `='.  (Until we do this,
	 it might be a `+'.)  */
      buf[0] = '=';
      /* Replace the constraint with the canonicalized string.  */
      *constraint_p = ggc_alloc_string (buf, c_len);
      constraint = *constraint_p;
    }

  /* Loop through the constraint string.  */
  for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
    switch (*p)
      {
      case '+':
      case '=':
	error ("operand constraint contains incorrectly positioned "
	       "%<+%> or %<=%>");
	return false;

      case '%':
	if (operand_num + 1 == ninputs + noutputs)
	  {
	    error ("%<%%%> constraint used with last operand");
	    return false;
	  }
	break;

      case 'V':  case TARGET_MEM_CONSTRAINT:  case 'o':
	*allows_mem = true;
	break;

      case '?':  case '!':  case '*':  case '&':  case '#':
      case 'E':  case 'F':  case 'G':  case 'H':
      case 's':  case 'i':  case 'n':
      case 'I':  case 'J':  case 'K':  case 'L':  case 'M':
      case 'N':  case 'O':  case 'P':  case ',':
	break;

      case '0':  case '1':  case '2':  case '3':  case '4':
      case '5':  case '6':  case '7':  case '8':  case '9':
      case '[':
	error ("matching constraint not valid in output operand");
	return false;

      case '<':  case '>':
	/* ??? Before flow, auto inc/dec insns are not supposed to exist,
	   excepting those that expand_call created.  So match memory
	   and hope.  */
	*allows_mem = true;
	break;

      case 'g':  case 'X':
	*allows_reg = true;
	*allows_mem = true;
	break;

      case 'p': case 'r':
	*allows_reg = true;
	break;

      default:
	if (!ISALPHA (*p))
	  break;
	if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
	  *allows_reg = true;
#ifdef EXTRA_CONSTRAINT_STR
	else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
	  *allows_reg = true;
	else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
	  *allows_mem = true;
	else
	  {
	    /* Otherwise we can't assume anything about the nature of
	       the constraint except that it isn't purely registers.
	       Treat it like "g" and hope for the best.  */
	    *allows_reg = true;
	    *allows_mem = true;
	  }
#endif
	break;
      }

  return true;
}

/* Similar, but for input constraints.  */

bool
parse_input_constraint (const char **constraint_p, int input_num,
			int ninputs, int noutputs, int ninout,
			const char * const * constraints,
			bool *allows_mem, bool *allows_reg)
{
  const char *constraint = *constraint_p;
  const char *orig_constraint = constraint;
  size_t c_len = strlen (constraint);
  size_t j;
  bool saw_match = false;

  /* Assume the constraint doesn't allow the use of either
     a register or memory.  */
  *allows_mem = false;
  *allows_reg = false;

  /* Make sure constraint has neither `=', `+', nor '&'.  */

  for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
    switch (constraint[j])
      {
      case '+':  case '=':  case '&':
	if (constraint == orig_constraint)
	  {
	    error ("input operand constraint contains %qc", constraint[j]);
	    return false;
	  }
	break;

      case '%':
	if (constraint == orig_constraint
	    && input_num + 1 == ninputs - ninout)
	  {
	    error ("%<%%%> constraint used with last operand");
	    return false;
	  }
	break;

      case 'V':  case TARGET_MEM_CONSTRAINT:  case 'o':
	*allows_mem = true;
	break;

      case '<':  case '>':
      case '?':  case '!':  case '*':  case '#':
      case 'E':  case 'F':  case 'G':  case 'H':
      case 's':  case 'i':  case 'n':
      case 'I':  case 'J':  case 'K':  case 'L':  case 'M':
      case 'N':  case 'O':  case 'P':  case ',':
	break;

	/* Whether or not a numeric constraint allows a register is
	   decided by the matching constraint, and so there is no need
	   to do anything special with them.  We must handle them in
	   the default case, so that we don't unnecessarily force
	   operands to memory.  */
      case '0':  case '1':  case '2':  case '3':  case '4':
      case '5':  case '6':  case '7':  case '8':  case '9':
	{
	  char *end;
	  unsigned long match;

	  saw_match = true;

	  match = strtoul (constraint + j, &end, 10);
	  if (match >= (unsigned long) noutputs)
	    {
	      error ("matching constraint references invalid operand number");
	      return false;
	    }

	  /* Try and find the real constraint for this dup.  Only do this
	     if the matching constraint is the only alternative.  */
	  if (*end == '\0'
	      && (j == 0 || (j == 1 && constraint[0] == '%')))
	    {
	      constraint = constraints[match];
	      *constraint_p = constraint;
	      c_len = strlen (constraint);
	      j = 0;
	      /* ??? At the end of the loop, we will skip the first part of
		 the matched constraint.  This assumes not only that the
		 other constraint is an output constraint, but also that
		 the '=' or '+' come first.  */
	      break;
	    }
	  else
	    j = end - constraint;
	  /* Anticipate increment at end of loop.  */
	  j--;
	}
	/* Fall through.  */

      case 'p':  case 'r':
	*allows_reg = true;
	break;

      case 'g':  case 'X':
	*allows_reg = true;
	*allows_mem = true;
	break;

      default:
	if (! ISALPHA (constraint[j]))
	  {
	    error ("invalid punctuation %qc in constraint", constraint[j]);
	    return false;
	  }
	if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
	    != NO_REGS)
	  *allows_reg = true;
#ifdef EXTRA_CONSTRAINT_STR
	else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
	  *allows_reg = true;
	else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
	  *allows_mem = true;
	else
	  {
	    /* Otherwise we can't assume anything about the nature of
	       the constraint except that it isn't purely registers.
	       Treat it like "g" and hope for the best.  */
	    *allows_reg = true;
	    *allows_mem = true;
	  }
#endif
	break;
      }

  if (saw_match && !*allows_reg)
    warning (0, "matching constraint does not allow a register");

  return true;
}

/* Return DECL iff there's an overlap between *REGS and DECL, where DECL
   can be an asm-declared register.  Called via walk_tree.  */

static tree
decl_overlaps_hard_reg_set_p (tree *declp, int *walk_subtrees ATTRIBUTE_UNUSED,
			      void *data)
{
  tree decl = *declp;
  const HARD_REG_SET *const regs = (const HARD_REG_SET *) data;

  if (TREE_CODE (decl) == VAR_DECL)
    {
      if (DECL_HARD_REGISTER (decl)
	  && REG_P (DECL_RTL (decl))
	  && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
	{
	  rtx reg = DECL_RTL (decl);

	  if (overlaps_hard_reg_set_p (*regs, GET_MODE (reg), REGNO (reg)))
	    return decl;
	}
      walk_subtrees = 0;
    }
  else if (TYPE_P (decl) || TREE_CODE (decl) == PARM_DECL)
    walk_subtrees = 0;
  return NULL_TREE;
}

/* If there is an overlap between *REGS and DECL, return the first overlap
   found.  */
tree
tree_overlaps_hard_reg_set (tree decl, HARD_REG_SET *regs)
{
  return walk_tree (&decl, decl_overlaps_hard_reg_set_p, regs, NULL);
}

/* Check for overlap between registers marked in CLOBBERED_REGS and
   anything inappropriate in T.  Emit error and return the register
   variable definition for error, NULL_TREE for ok.  */

static bool
tree_conflicts_with_clobbers_p (tree t, HARD_REG_SET *clobbered_regs)
{
  /* Conflicts between asm-declared register variables and the clobber
     list are not allowed.  */
  tree overlap = tree_overlaps_hard_reg_set (t, clobbered_regs);

  if (overlap)
    {
      error ("asm-specifier for variable %qE conflicts with asm clobber list",
	     DECL_NAME (overlap));

      /* Reset registerness to stop multiple errors emitted for a single
	 variable.  */
      DECL_REGISTER (overlap) = 0;
      return true;
    }

  return false;
}

/* Generate RTL for an asm statement with arguments.
   STRING is the instruction template.
   OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
   Each output or input has an expression in the TREE_VALUE and
   a tree list in TREE_PURPOSE which in turn contains a constraint
   name in TREE_VALUE (or NULL_TREE) and a constraint string
   in TREE_PURPOSE.
   CLOBBERS is a list of STRING_CST nodes each naming a hard register
   that is clobbered by this insn.

   Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
   Some elements of OUTPUTS may be replaced with trees representing temporary
   values.  The caller should copy those temporary values to the originally
   specified lvalues.

   VOL nonzero means the insn is volatile; don't optimize it.  */

static void
expand_asm_operands (tree string, tree outputs, tree inputs,
		     tree clobbers, tree labels, int vol, location_t locus)
{
  rtvec argvec, constraintvec, labelvec;
  rtx body;
  int ninputs = list_length (inputs);
  int noutputs = list_length (outputs);
  int nlabels = list_length (labels);
  int ninout;
  int nclobbers;
  HARD_REG_SET clobbered_regs;
  int clobber_conflict_found = 0;
  tree tail;
  tree t;
  int i;
  /* Vector of RTX's of evaluated output operands.  */
  rtx *output_rtx = XALLOCAVEC (rtx, noutputs);
  int *inout_opnum = XALLOCAVEC (int, noutputs);
  rtx *real_output_rtx = XALLOCAVEC (rtx, noutputs);
  enum machine_mode *inout_mode = XALLOCAVEC (enum machine_mode, noutputs);
  const char **constraints = XALLOCAVEC (const char *, noutputs + ninputs);
  int old_generating_concat_p = generating_concat_p;

  /* An ASM with no outputs needs to be treated as volatile, for now.  */
  if (noutputs == 0)
    vol = 1;

  if (! check_operand_nalternatives (outputs, inputs))
    return;

  string = resolve_asm_operand_names (string, outputs, inputs, labels);

  /* Collect constraints.  */
  i = 0;
  for (t = outputs; t ; t = TREE_CHAIN (t), i++)
    constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
  for (t = inputs; t ; t = TREE_CHAIN (t), i++)
    constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));

  /* Sometimes we wish to automatically clobber registers across an asm.
     Case in point is when the i386 backend moved from cc0 to a hard reg --
     maintaining source-level compatibility means automatically clobbering
     the flags register.  */
  clobbers = targetm.md_asm_clobbers (outputs, inputs, clobbers);

  /* Count the number of meaningful clobbered registers, ignoring what
     we would ignore later.  */
  nclobbers = 0;
  CLEAR_HARD_REG_SET (clobbered_regs);
  for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
    {
      const char *regname;
      int nregs;

      if (TREE_VALUE (tail) == error_mark_node)
	return;
      regname = TREE_STRING_POINTER (TREE_VALUE (tail));

      i = decode_reg_name_and_count (regname, &nregs);
      if (i == -4)
	++nclobbers;
      else if (i == -2)
	error ("unknown register name %qs in %<asm%>", regname);

      /* Mark clobbered registers.  */
      if (i >= 0)
        {
	  int reg;

	  for (reg = i; reg < i + nregs; reg++)
	    {
	      ++nclobbers;

	      /* Clobbering the PIC register is an error.  */
	      if (reg == (int) PIC_OFFSET_TABLE_REGNUM)
		{
		  error ("PIC register clobbered by %qs in %<asm%>", regname);
		  return;
		}

	      SET_HARD_REG_BIT (clobbered_regs, reg);
	    }
	}
    }

  /* First pass over inputs and outputs checks validity and sets
     mark_addressable if needed.  */

  ninout = 0;
  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
    {
      tree val = TREE_VALUE (tail);
      tree type = TREE_TYPE (val);
      const char *constraint;
      bool is_inout;
      bool allows_reg;
      bool allows_mem;

      /* If there's an erroneous arg, emit no insn.  */
      if (type == error_mark_node)
	return;

      /* Try to parse the output constraint.  If that fails, there's
	 no point in going further.  */
      constraint = constraints[i];
      if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
				    &allows_mem, &allows_reg, &is_inout))
	return;

      if (! allows_reg
	  && (allows_mem
	      || is_inout
	      || (DECL_P (val)
		  && REG_P (DECL_RTL (val))
		  && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
	mark_addressable (val);

      if (is_inout)
	ninout++;
    }

  ninputs += ninout;
  if (ninputs + noutputs > MAX_RECOG_OPERANDS)
    {
      error ("more than %d operands in %<asm%>", MAX_RECOG_OPERANDS);
      return;
    }

  for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
    {
      bool allows_reg, allows_mem;
      const char *constraint;

      /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
	 would get VOIDmode and that could cause a crash in reload.  */
      if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
	return;

      constraint = constraints[i + noutputs];
      if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
				    constraints, &allows_mem, &allows_reg))
	return;

      if (! allows_reg && allows_mem)
	mark_addressable (TREE_VALUE (tail));
    }

  /* Second pass evaluates arguments.  */

  /* Make sure stack is consistent for asm goto.  */
  if (nlabels > 0)
    do_pending_stack_adjust ();

  ninout = 0;
  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
    {
      tree val = TREE_VALUE (tail);
      tree type = TREE_TYPE (val);
      bool is_inout;
      bool allows_reg;
      bool allows_mem;
      rtx op;
      bool ok;

      ok = parse_output_constraint (&constraints[i], i, ninputs,
				    noutputs, &allows_mem, &allows_reg,
				    &is_inout);
      gcc_assert (ok);

      /* If an output operand is not a decl or indirect ref and our constraint
	 allows a register, make a temporary to act as an intermediate.
	 Make the asm insn write into that, then our caller will copy it to
	 the real output operand.  Likewise for promoted variables.  */

      generating_concat_p = 0;

      real_output_rtx[i] = NULL_RTX;
      if ((TREE_CODE (val) == INDIRECT_REF
	   && allows_mem)
	  || (DECL_P (val)
	      && (allows_mem || REG_P (DECL_RTL (val)))
	      && ! (REG_P (DECL_RTL (val))
		    && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
	  || ! allows_reg
	  || is_inout)
	{
	  op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
	  if (MEM_P (op))
	    op = validize_mem (op);

	  if (! allows_reg && !MEM_P (op))
	    error ("output number %d not directly addressable", i);
	  if ((! allows_mem && MEM_P (op))
	      || GET_CODE (op) == CONCAT)
	    {
	      real_output_rtx[i] = op;
	      op = gen_reg_rtx (GET_MODE (op));
	      if (is_inout)
		emit_move_insn (op, real_output_rtx[i]);
	    }
	}
      else
	{
	  op = assign_temp (type, 0, 1);
	  op = validize_mem (op);
	  if (!MEM_P (op) && TREE_CODE (TREE_VALUE (tail)) == SSA_NAME)
	    set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (TREE_VALUE (tail)), op);
	  TREE_VALUE (tail) = make_tree (type, op);
	}
      output_rtx[i] = op;

      generating_concat_p = old_generating_concat_p;

      if (is_inout)
	{
	  inout_mode[ninout] = TYPE_MODE (type);
	  inout_opnum[ninout++] = i;
	}

      if (tree_conflicts_with_clobbers_p (val, &clobbered_regs))
	clobber_conflict_found = 1;
    }

  /* Make vectors for the expression-rtx, constraint strings,
     and named operands.  */

  argvec = rtvec_alloc (ninputs);
  constraintvec = rtvec_alloc (ninputs);
  labelvec = rtvec_alloc (nlabels);

  body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
				: GET_MODE (output_rtx[0])),
			       ggc_strdup (TREE_STRING_POINTER (string)),
			       empty_string, 0, argvec, constraintvec,
			       labelvec, locus);

  MEM_VOLATILE_P (body) = vol;

  /* Eval the inputs and put them into ARGVEC.
     Put their constraints into ASM_INPUTs and store in CONSTRAINTS.  */

  for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
    {
      bool allows_reg, allows_mem;
      const char *constraint;
      tree val, type;
      rtx op;
      bool ok;

      constraint = constraints[i + noutputs];
      ok = parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
				   constraints, &allows_mem, &allows_reg);
      gcc_assert (ok);

      generating_concat_p = 0;

      val = TREE_VALUE (tail);
      type = TREE_TYPE (val);
      /* EXPAND_INITIALIZER will not generate code for valid initializer
	 constants, but will still generate code for other types of operand.
	 This is the behavior we want for constant constraints.  */
      op = expand_expr (val, NULL_RTX, VOIDmode,
			allows_reg ? EXPAND_NORMAL
			: allows_mem ? EXPAND_MEMORY
			: EXPAND_INITIALIZER);

      /* Never pass a CONCAT to an ASM.  */
      if (GET_CODE (op) == CONCAT)
	op = force_reg (GET_MODE (op), op);
      else if (MEM_P (op))
	op = validize_mem (op);

      if (asm_operand_ok (op, constraint, NULL) <= 0)
	{
	  if (allows_reg && TYPE_MODE (type) != BLKmode)
	    op = force_reg (TYPE_MODE (type), op);
	  else if (!allows_mem)
	    warning (0, "asm operand %d probably doesn%'t match constraints",
		     i + noutputs);
	  else if (MEM_P (op))
	    {
	      /* We won't recognize either volatile memory or memory
		 with a queued address as available a memory_operand
		 at this point.  Ignore it: clearly this *is* a memory.  */
	    }
	  else
	    gcc_unreachable ();
	}

      generating_concat_p = old_generating_concat_p;
      ASM_OPERANDS_INPUT (body, i) = op;

      ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
	= gen_rtx_ASM_INPUT (TYPE_MODE (type),
			     ggc_strdup (constraints[i + noutputs]));

      if (tree_conflicts_with_clobbers_p (val, &clobbered_regs))
	clobber_conflict_found = 1;
    }

  /* Protect all the operands from the queue now that they have all been
     evaluated.  */

  generating_concat_p = 0;

  /* For in-out operands, copy output rtx to input rtx.  */
  for (i = 0; i < ninout; i++)
    {
      int j = inout_opnum[i];
      char buffer[16];

      ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
	= output_rtx[j];

      sprintf (buffer, "%d", j);
      ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
	= gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
    }

  /* Copy labels to the vector.  */
  for (i = 0, tail = labels; i < nlabels; ++i, tail = TREE_CHAIN (tail))
    ASM_OPERANDS_LABEL (body, i)
      = gen_rtx_LABEL_REF (Pmode, label_rtx (TREE_VALUE (tail)));

  generating_concat_p = old_generating_concat_p;

  /* Now, for each output, construct an rtx
     (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
			       ARGVEC CONSTRAINTS OPNAMES))
     If there is more than one, put them inside a PARALLEL.  */

  if (nlabels > 0 && nclobbers == 0)
    {
      gcc_assert (noutputs == 0);
      emit_jump_insn (body);
    }
  else if (noutputs == 0 && nclobbers == 0)
    {
      /* No output operands: put in a raw ASM_OPERANDS rtx.  */
      emit_insn (body);
    }
  else if (noutputs == 1 && nclobbers == 0)
    {
      ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = ggc_strdup (constraints[0]);
      emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
    }
  else
    {
      rtx obody = body;
      int num = noutputs;

      if (num == 0)
	num = 1;

      body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));

      /* For each output operand, store a SET.  */
      for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
	{
	  XVECEXP (body, 0, i)
	    = gen_rtx_SET (VOIDmode,
			   output_rtx[i],
			   gen_rtx_ASM_OPERANDS
			   (GET_MODE (output_rtx[i]),
			    ggc_strdup (TREE_STRING_POINTER (string)),
			    ggc_strdup (constraints[i]),
			    i, argvec, constraintvec, labelvec, locus));

	  MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
	}

      /* If there are no outputs (but there are some clobbers)
	 store the bare ASM_OPERANDS into the PARALLEL.  */

      if (i == 0)
	XVECEXP (body, 0, i++) = obody;

      /* Store (clobber REG) for each clobbered register specified.  */

      for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
	{
	  const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
	  int reg, nregs;
	  int j = decode_reg_name_and_count (regname, &nregs);
	  rtx clobbered_reg;

	  if (j < 0)
	    {
	      if (j == -3)	/* `cc', which is not a register */
		continue;

	      if (j == -4)	/* `memory', don't cache memory across asm */
		{
		  XVECEXP (body, 0, i++)
		    = gen_rtx_CLOBBER (VOIDmode,
				       gen_rtx_MEM
				       (BLKmode,
					gen_rtx_SCRATCH (VOIDmode)));
		  continue;
		}

	      /* Ignore unknown register, error already signaled.  */
	      continue;
	    }

	  for (reg = j; reg < j + nregs; reg++)
	    {
	      /* Use QImode since that's guaranteed to clobber just
	       * one reg.  */
	      clobbered_reg = gen_rtx_REG (QImode, reg);

	      /* Do sanity check for overlap between clobbers and
		 respectively input and outputs that hasn't been
		 handled.  Such overlap should have been detected and
		 reported above.  */
	      if (!clobber_conflict_found)
		{
		  int opno;

		  /* We test the old body (obody) contents to avoid
		     tripping over the under-construction body.  */
		  for (opno = 0; opno < noutputs; opno++)
		    if (reg_overlap_mentioned_p (clobbered_reg,
						 output_rtx[opno]))
		      internal_error
			("asm clobber conflict with output operand");

		  for (opno = 0; opno < ninputs - ninout; opno++)
		    if (reg_overlap_mentioned_p (clobbered_reg,
						 ASM_OPERANDS_INPUT (obody,
								     opno)))
		      internal_error
			("asm clobber conflict with input operand");
		}

	      XVECEXP (body, 0, i++)
		= gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
	    }
	}

      if (nlabels > 0)
	emit_jump_insn (body);
      else
	emit_insn (body);
    }

  /* For any outputs that needed reloading into registers, spill them
     back to where they belong.  */
  for (i = 0; i < noutputs; ++i)
    if (real_output_rtx[i])
      emit_move_insn (real_output_rtx[i], output_rtx[i]);

  crtl->has_asm_statement = 1;
  free_temp_slots ();
}

void
expand_asm_stmt (gimple stmt)
{
  int noutputs;
  tree outputs, tail, t;
  tree *o;
  size_t i, n;
  const char *s;
  tree str, out, in, cl, labels;
  location_t locus = gimple_location (stmt);

  /* Meh... convert the gimple asm operands into real tree lists.
     Eventually we should make all routines work on the vectors instead
     of relying on TREE_CHAIN.  */
  out = NULL_TREE;
  n = gimple_asm_noutputs (stmt);
  if (n > 0)
    {
      t = out = gimple_asm_output_op (stmt, 0);
      for (i = 1; i < n; i++)
	t = TREE_CHAIN (t) = gimple_asm_output_op (stmt, i);
    }

  in = NULL_TREE;
  n = gimple_asm_ninputs (stmt);
  if (n > 0)
    {
      t = in = gimple_asm_input_op (stmt, 0);
      for (i = 1; i < n; i++)
	t = TREE_CHAIN (t) = gimple_asm_input_op (stmt, i);
    }

  cl = NULL_TREE;
  n = gimple_asm_nclobbers (stmt);
  if (n > 0)
    {
      t = cl = gimple_asm_clobber_op (stmt, 0);
      for (i = 1; i < n; i++)
	t = TREE_CHAIN (t) = gimple_asm_clobber_op (stmt, i);
    }

  labels = NULL_TREE;
  n = gimple_asm_nlabels (stmt);
  if (n > 0)
    {
      t = labels = gimple_asm_label_op (stmt, 0);
      for (i = 1; i < n; i++)
	t = TREE_CHAIN (t) = gimple_asm_label_op (stmt, i);
    }

  s = gimple_asm_string (stmt);
  str = build_string (strlen (s), s);

  if (gimple_asm_input_p (stmt))
    {
      expand_asm_loc (str, gimple_asm_volatile_p (stmt), locus);
      return;
    }

  outputs = out;
  noutputs = gimple_asm_noutputs (stmt);
  /* o[I] is the place that output number I should be written.  */
  o = (tree *) alloca (noutputs * sizeof (tree));

  /* Record the contents of OUTPUTS before it is modified.  */
  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
    o[i] = TREE_VALUE (tail);

  /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
     OUTPUTS some trees for where the values were actually stored.  */
  expand_asm_operands (str, outputs, in, cl, labels,
		       gimple_asm_volatile_p (stmt), locus);

  /* Copy all the intermediate outputs into the specified outputs.  */
  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
    {
      if (o[i] != TREE_VALUE (tail))
	{
	  expand_assignment (o[i], TREE_VALUE (tail), false);
	  free_temp_slots ();

	  /* Restore the original value so that it's correct the next
	     time we expand this function.  */
	  TREE_VALUE (tail) = o[i];
	}
    }
}

/* A subroutine of expand_asm_operands.  Check that all operands have
   the same number of alternatives.  Return true if so.  */

static bool
check_operand_nalternatives (tree outputs, tree inputs)
{
  if (outputs || inputs)
    {
      tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
      int nalternatives
	= n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
      tree next = inputs;

      if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
	{
	  error ("too many alternatives in %<asm%>");
	  return false;
	}

      tmp = outputs;
      while (tmp)
	{
	  const char *constraint
	    = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));

	  if (n_occurrences (',', constraint) != nalternatives)
	    {
	      error ("operand constraints for %<asm%> differ "
		     "in number of alternatives");
	      return false;
	    }

	  if (TREE_CHAIN (tmp))
	    tmp = TREE_CHAIN (tmp);
	  else
	    tmp = next, next = 0;
	}
    }

  return true;
}

/* A subroutine of expand_asm_operands.  Check that all operand names
   are unique.  Return true if so.  We rely on the fact that these names
   are identifiers, and so have been canonicalized by get_identifier,
   so all we need are pointer comparisons.  */

static bool
check_unique_operand_names (tree outputs, tree inputs, tree labels)
{
  tree i, j, i_name = NULL_TREE;

  for (i = outputs; i ; i = TREE_CHAIN (i))
    {
      i_name = TREE_PURPOSE (TREE_PURPOSE (i));
      if (! i_name)
	continue;

      for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
	if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
	  goto failure;
    }

  for (i = inputs; i ; i = TREE_CHAIN (i))
    {
      i_name = TREE_PURPOSE (TREE_PURPOSE (i));
      if (! i_name)
	continue;

      for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
	if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
	  goto failure;
      for (j = outputs; j ; j = TREE_CHAIN (j))
	if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
	  goto failure;
    }

  for (i = labels; i ; i = TREE_CHAIN (i))
    {
      i_name = TREE_PURPOSE (i);
      if (! i_name)
	continue;

      for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
	if (simple_cst_equal (i_name, TREE_PURPOSE (j)))
	  goto failure;
      for (j = inputs; j ; j = TREE_CHAIN (j))
	if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
	  goto failure;
    }

  return true;

 failure:
  error ("duplicate asm operand name %qs", TREE_STRING_POINTER (i_name));
  return false;
}

/* A subroutine of expand_asm_operands.  Resolve the names of the operands
   in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
   STRING and in the constraints to those numbers.  */

tree
resolve_asm_operand_names (tree string, tree outputs, tree inputs, tree labels)
{
  char *buffer;
  char *p;
  const char *c;
  tree t;

  check_unique_operand_names (outputs, inputs, labels);

  /* Substitute [<name>] in input constraint strings.  There should be no
     named operands in output constraints.  */
  for (t = inputs; t ; t = TREE_CHAIN (t))
    {
      c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
      if (strchr (c, '[') != NULL)
	{
	  p = buffer = xstrdup (c);
	  while ((p = strchr (p, '[')) != NULL)
	    p = resolve_operand_name_1 (p, outputs, inputs, NULL);
	  TREE_VALUE (TREE_PURPOSE (t))
	    = build_string (strlen (buffer), buffer);
	  free (buffer);
	}
    }

  /* Now check for any needed substitutions in the template.  */
  c = TREE_STRING_POINTER (string);
  while ((c = strchr (c, '%')) != NULL)
    {
      if (c[1] == '[')
	break;
      else if (ISALPHA (c[1]) && c[2] == '[')
	break;
      else
	{
	  c += 1 + (c[1] == '%');
	  continue;
	}
    }

  if (c)
    {
      /* OK, we need to make a copy so we can perform the substitutions.
	 Assume that we will not need extra space--we get to remove '['
	 and ']', which means we cannot have a problem until we have more
	 than 999 operands.  */
      buffer = xstrdup (TREE_STRING_POINTER (string));
      p = buffer + (c - TREE_STRING_POINTER (string));

      while ((p = strchr (p, '%')) != NULL)
	{
	  if (p[1] == '[')
	    p += 1;
	  else if (ISALPHA (p[1]) && p[2] == '[')
	    p += 2;
	  else
	    {
	      p += 1 + (p[1] == '%');
	      continue;
	    }

	  p = resolve_operand_name_1 (p, outputs, inputs, labels);
	}

      string = build_string (strlen (buffer), buffer);
      free (buffer);
    }

  return string;
}

/* A subroutine of resolve_operand_names.  P points to the '[' for a
   potential named operand of the form [<name>].  In place, replace
   the name and brackets with a number.  Return a pointer to the
   balance of the string after substitution.  */

static char *
resolve_operand_name_1 (char *p, tree outputs, tree inputs, tree labels)
{
  char *q;
  int op;
  tree t;

  /* Collect the operand name.  */
  q = strchr (++p, ']');
  if (!q)
    {
      error ("missing close brace for named operand");
      return strchr (p, '\0');
    }
  *q = '\0';

  /* Resolve the name to a number.  */
  for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
    {
      tree name = TREE_PURPOSE (TREE_PURPOSE (t));
      if (name && strcmp (TREE_STRING_POINTER (name), p) == 0)
	goto found;
    }
  for (t = inputs; t ; t = TREE_CHAIN (t), op++)
    {
      tree name = TREE_PURPOSE (TREE_PURPOSE (t));
      if (name && strcmp (TREE_STRING_POINTER (name), p) == 0)
	goto found;
    }
  for (t = labels; t ; t = TREE_CHAIN (t), op++)
    {
      tree name = TREE_PURPOSE (t);
      if (name && strcmp (TREE_STRING_POINTER (name), p) == 0)
	goto found;
    }

  error ("undefined named operand %qs", identifier_to_locale (p));
  op = 0;

 found:
  /* Replace the name with the number.  Unfortunately, not all libraries
     get the return value of sprintf correct, so search for the end of the
     generated string by hand.  */
  sprintf (--p, "%d", op);
  p = strchr (p, '\0');

  /* Verify the no extra buffer space assumption.  */
  gcc_assert (p <= q);

  /* Shift the rest of the buffer down to fill the gap.  */
  memmove (p, q + 1, strlen (q + 1) + 1);

  return p;
}

/* Generate RTL to return from the current function, with no value.
   (That is, we do not do anything about returning any value.)  */

void
expand_null_return (void)
{
  /* If this function was declared to return a value, but we
     didn't, clobber the return registers so that they are not
     propagated live to the rest of the function.  */
  clobber_return_register ();

  expand_null_return_1 ();
}

/* Generate RTL to return directly from the current function.
   (That is, we bypass any return value.)  */

void
expand_naked_return (void)
{
  rtx end_label;

  clear_pending_stack_adjust ();
  do_pending_stack_adjust ();

  end_label = naked_return_label;
  if (end_label == 0)
    end_label = naked_return_label = gen_label_rtx ();

  emit_jump (end_label);
}

/* Generate RTL to return from the current function, with value VAL.  */

static void
expand_value_return (rtx val)
{
  /* Copy the value to the return location unless it's already there.  */

  tree decl = DECL_RESULT (current_function_decl);
  rtx return_reg = DECL_RTL (decl);
  if (return_reg != val)
    {
      tree funtype = TREE_TYPE (current_function_decl);
      tree type = TREE_TYPE (decl);
      int unsignedp = TYPE_UNSIGNED (type);
      enum machine_mode old_mode = DECL_MODE (decl);
      enum machine_mode mode;
      if (DECL_BY_REFERENCE (decl))
        mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 2);
      else
        mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 1);

      if (mode != old_mode)
	val = convert_modes (mode, old_mode, val, unsignedp);

      if (GET_CODE (return_reg) == PARALLEL)
	emit_group_load (return_reg, val, type, int_size_in_bytes (type));
      else
	emit_move_insn (return_reg, val);
    }

  expand_null_return_1 ();
}

/* Output a return with no value.  */

static void
expand_null_return_1 (void)
{
  clear_pending_stack_adjust ();
  do_pending_stack_adjust ();
  emit_jump (return_label);
}

/* Generate RTL to evaluate the expression RETVAL and return it
   from the current function.  */

void
expand_return (tree retval)
{
  rtx result_rtl;
  rtx val = 0;
  tree retval_rhs;

  /* If function wants no value, give it none.  */
  if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
    {
      expand_normal (retval);
      expand_null_return ();
      return;
    }

  if (retval == error_mark_node)
    {
      /* Treat this like a return of no value from a function that
	 returns a value.  */
      expand_null_return ();
      return;
    }
  else if ((TREE_CODE (retval) == MODIFY_EXPR
	    || TREE_CODE (retval) == INIT_EXPR)
	   && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
    retval_rhs = TREE_OPERAND (retval, 1);
  else
    retval_rhs = retval;

  result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));

  /* If we are returning the RESULT_DECL, then the value has already
     been stored into it, so we don't have to do anything special.  */
  if (TREE_CODE (retval_rhs) == RESULT_DECL)
    expand_value_return (result_rtl);

  /* If the result is an aggregate that is being returned in one (or more)
     registers, load the registers here.  */

  else if (retval_rhs != 0
	   && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
	   && REG_P (result_rtl))
    {
      val = copy_blkmode_to_reg (GET_MODE (result_rtl), retval_rhs);
      if (val)
	{
	  /* Use the mode of the result value on the return register.  */
	  PUT_MODE (result_rtl, GET_MODE (val));
	  expand_value_return (val);
	}
      else
	expand_null_return ();
    }
  else if (retval_rhs != 0
	   && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
	   && (REG_P (result_rtl)
	       || (GET_CODE (result_rtl) == PARALLEL)))
    {
      /* Calculate the return value into a temporary (usually a pseudo
         reg).  */
      tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
      tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);

      val = assign_temp (nt, 0, 1);
      val = expand_expr (retval_rhs, val, GET_MODE (val), EXPAND_NORMAL);
      val = force_not_mem (val);
      /* Return the calculated value.  */
      expand_value_return (val);
    }
  else
    {
      /* No hard reg used; calculate value into hard return reg.  */
      expand_expr (retval, const0_rtx, VOIDmode, EXPAND_NORMAL);
      expand_value_return (result_rtl);
    }
}

/* Emit code to restore vital registers at the beginning of a nonlocal goto
   handler.  */
static void
expand_nl_goto_receiver (void)
{
  rtx chain;

  /* Clobber the FP when we get here, so we have to make sure it's
     marked as used by this function.  */
  emit_use (hard_frame_pointer_rtx);

  /* Mark the static chain as clobbered here so life information
     doesn't get messed up for it.  */
  chain = targetm.calls.static_chain (current_function_decl, true);
  if (chain && REG_P (chain))
    emit_clobber (chain);

#ifdef HAVE_nonlocal_goto
  if (! HAVE_nonlocal_goto)
#endif
    /* First adjust our frame pointer to its actual value.  It was
       previously set to the start of the virtual area corresponding to
       the stacked variables when we branched here and now needs to be
       adjusted to the actual hardware fp value.

       Assignments are to virtual registers are converted by
       instantiate_virtual_regs into the corresponding assignment
       to the underlying register (fp in this case) that makes
       the original assignment true.
       So the following insn will actually be
       decrementing fp by STARTING_FRAME_OFFSET.  */
    emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);

#if !HARD_FRAME_POINTER_IS_ARG_POINTER
  if (fixed_regs[ARG_POINTER_REGNUM])
    {
#ifdef ELIMINABLE_REGS
      /* If the argument pointer can be eliminated in favor of the
	 frame pointer, we don't need to restore it.  We assume here
	 that if such an elimination is present, it can always be used.
	 This is the case on all known machines; if we don't make this
	 assumption, we do unnecessary saving on many machines.  */
      static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
      size_t i;

      for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
	if (elim_regs[i].from == ARG_POINTER_REGNUM
	    && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
	  break;

      if (i == ARRAY_SIZE (elim_regs))
#endif
	{
	  /* Now restore our arg pointer from the address at which it
	     was saved in our stack frame.  */
	  emit_move_insn (crtl->args.internal_arg_pointer,
			  copy_to_reg (get_arg_pointer_save_area ()));
	}
    }
#endif

#ifdef HAVE_nonlocal_goto_receiver
  if (HAVE_nonlocal_goto_receiver)
    emit_insn (gen_nonlocal_goto_receiver ());
#endif

  /* We must not allow the code we just generated to be reordered by
     scheduling.  Specifically, the update of the frame pointer must
     happen immediately, not later.  */
  emit_insn (gen_blockage ());
}

/* Emit code to save the current value of stack.  */
rtx
expand_stack_save (void)
{
  rtx ret = NULL_RTX;

  do_pending_stack_adjust ();
  emit_stack_save (SAVE_BLOCK, &ret);
  return ret;
}

/* Emit code to restore the current value of stack.  */
void
expand_stack_restore (tree var)
{
  rtx prev, sa = expand_normal (var);

  sa = convert_memory_address (Pmode, sa);

  prev = get_last_insn ();
  emit_stack_restore (SAVE_BLOCK, sa);
  fixup_args_size_notes (prev, get_last_insn (), 0);
}

/* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. PROB
   is the probability of jumping to LABEL.  */
static void
do_jump_if_equal (enum machine_mode mode, rtx op0, rtx op1, rtx label,
		  int unsignedp, int prob)
{
  gcc_assert (prob <= REG_BR_PROB_BASE);
  do_compare_rtx_and_jump (op0, op1, EQ, unsignedp, mode,
			   NULL_RTX, NULL_RTX, label, prob);
}

/* Do the insertion of a case label into case_list.  The labels are
   fed to us in descending order from the sorted vector of case labels used
   in the tree part of the middle end.  So the list we construct is
   sorted in ascending order.
   
   LABEL is the case label to be inserted. LOW and HIGH are the bounds
   against which the index is compared to jump to LABEL and PROB is the
   estimated probability LABEL is reached from the switch statement.  */

static struct case_node *
add_case_node (struct case_node *head, tree low, tree high,
               tree label, int prob, alloc_pool case_node_pool)
{
  struct case_node *r;

  gcc_checking_assert (low);
  gcc_checking_assert (high && (TREE_TYPE (low) == TREE_TYPE (high)));

  /* Add this label to the chain.  */
  r = (struct case_node *) pool_alloc (case_node_pool);
  r->low = low;
  r->high = high;
  r->code_label = label;
  r->parent = r->left = NULL;
  r->prob = prob;
  r->subtree_prob = prob;
  r->right = head;
  return r;
}

/* Dump ROOT, a list or tree of case nodes, to file.  */

static void
dump_case_nodes (FILE *f, struct case_node *root,
		 int indent_step, int indent_level)
{
  HOST_WIDE_INT low, high;

  if (root == 0)
    return;
  indent_level++;

  dump_case_nodes (f, root->left, indent_step, indent_level);

  low = tree_low_cst (root->low, 0);
  high = tree_low_cst (root->high, 0);

  fputs (";; ", f);
  if (high == low)
    fprintf(f, "%*s" HOST_WIDE_INT_PRINT_DEC,
	    indent_step * indent_level, "", low);
  else
    fprintf(f, "%*s" HOST_WIDE_INT_PRINT_DEC " ... " HOST_WIDE_INT_PRINT_DEC,
	    indent_step * indent_level, "", low, high);
  fputs ("\n", f);

  dump_case_nodes (f, root->right, indent_step, indent_level);
}

#ifndef HAVE_casesi
#define HAVE_casesi 0
#endif

#ifndef HAVE_tablejump
#define HAVE_tablejump 0
#endif

/* Return the smallest number of different values for which it is best to use a
   jump-table instead of a tree of conditional branches.  */

static unsigned int
case_values_threshold (void)
{
  unsigned int threshold = PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD);

  if (threshold == 0)
    threshold = targetm.case_values_threshold ();

  return threshold;
}

/* Return true if a switch should be expanded as a decision tree.
   RANGE is the difference between highest and lowest case.
   UNIQ is number of unique case node targets, not counting the default case.
   COUNT is the number of comparisons needed, not counting the default case.  */

static bool
expand_switch_as_decision_tree_p (tree range,
				  unsigned int uniq ATTRIBUTE_UNUSED,
				  unsigned int count)
{
  int max_ratio;

  /* If neither casesi or tablejump is available, or flag_jump_tables
     over-ruled us, we really have no choice.  */
  if (!HAVE_casesi && !HAVE_tablejump)
    return true;
  if (!flag_jump_tables)
    return true;
#ifndef ASM_OUTPUT_ADDR_DIFF_ELT
  if (flag_pic)
    return true;
#endif

  /* If the switch is relatively small such that the cost of one
     indirect jump on the target are higher than the cost of a
     decision tree, go with the decision tree.

     If range of values is much bigger than number of values,
     or if it is too large to represent in a HOST_WIDE_INT,
     make a sequence of conditional branches instead of a dispatch.

     The definition of "much bigger" depends on whether we are
     optimizing for size or for speed.  If the former, the maximum
     ratio range/count = 3, because this was found to be the optimal
     ratio for size on i686-pc-linux-gnu, see PR11823.  The ratio
     10 is much older, and was probably selected after an extensive
     benchmarking investigation on numerous platforms.  Or maybe it
     just made sense to someone at some point in the history of GCC,
     who knows...  */
  max_ratio = optimize_insn_for_size_p () ? 3 : 10;
  if (count < case_values_threshold ()
      || ! host_integerp (range, /*pos=*/1)
      || compare_tree_int (range, max_ratio * count) > 0)
    return true;

  return false;
}

/* Generate a decision tree, switching on INDEX_EXPR and jumping to
   one of the labels in CASE_LIST or to the DEFAULT_LABEL.
   DEFAULT_PROB is the estimated probability that it jumps to
   DEFAULT_LABEL.
   
   We generate a binary decision tree to select the appropriate target
   code.  This is done as follows:

     If the index is a short or char that we do not have
     an insn to handle comparisons directly, convert it to
     a full integer now, rather than letting each comparison
     generate the conversion.

     Load the index into a register.

     The list of cases is rearranged into a binary tree,
     nearly optimal assuming equal probability for each case.

     The tree is transformed into RTL, eliminating redundant
     test conditions at the same time.

     If program flow could reach the end of the decision tree
     an unconditional jump to the default code is emitted.

   The above process is unaware of the CFG.  The caller has to fix up
   the CFG itself.  This is done in cfgexpand.c.  */     

static void
emit_case_decision_tree (tree index_expr, tree index_type,
			 struct case_node *case_list, rtx default_label,
                         int default_prob)
{
  rtx index = expand_normal (index_expr);

  if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
      && ! have_insn_for (COMPARE, GET_MODE (index)))
    {
      int unsignedp = TYPE_UNSIGNED (index_type);
      enum machine_mode wider_mode;
      for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
	   wider_mode = GET_MODE_WIDER_MODE (wider_mode))
	if (have_insn_for (COMPARE, wider_mode))
	  {
	    index = convert_to_mode (wider_mode, index, unsignedp);
	    break;
	  }
    }

  do_pending_stack_adjust ();

  if (MEM_P (index))
    {
      index = copy_to_reg (index);
      if (TREE_CODE (index_expr) == SSA_NAME)
	set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (index_expr), index);
    }

  balance_case_nodes (&case_list, NULL);

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      int indent_step = ceil_log2 (TYPE_PRECISION (index_type)) + 2;
      fprintf (dump_file, ";; Expanding GIMPLE switch as decision tree:\n");
      dump_case_nodes (dump_file, case_list, indent_step, 0);
    }

  emit_case_nodes (index, case_list, default_label, default_prob, index_type);
  if (default_label)
    emit_jump (default_label);
}

/* Return the sum of probabilities of outgoing edges of basic block BB.  */

static int
get_outgoing_edge_probs (basic_block bb)
{
  edge e;
  edge_iterator ei;
  int prob_sum = 0;
  if (!bb)
    return 0;
  FOR_EACH_EDGE(e, ei, bb->succs)
    prob_sum += e->probability;
  return prob_sum;
}

/* Computes the conditional probability of jumping to a target if the branch
   instruction is executed.
   TARGET_PROB is the estimated probability of jumping to a target relative
   to some basic block BB.
   BASE_PROB is the probability of reaching the branch instruction relative
   to the same basic block BB.  */

static inline int
conditional_probability (int target_prob, int base_prob)
{
  if (base_prob > 0)
    {
      gcc_assert (target_prob >= 0);
      gcc_assert (target_prob <= base_prob);
      return GCOV_COMPUTE_SCALE (target_prob, base_prob);
    }
  return -1;
}

/* Generate a dispatch tabler, switching on INDEX_EXPR and jumping to
   one of the labels in CASE_LIST or to the DEFAULT_LABEL.
   MINVAL, MAXVAL, and RANGE are the extrema and range of the case
   labels in CASE_LIST. STMT_BB is the basic block containing the statement.

   First, a jump insn is emitted.  First we try "casesi".  If that
   fails, try "tablejump".   A target *must* have one of them (or both).

   Then, a table with the target labels is emitted.

   The process is unaware of the CFG.  The caller has to fix up
   the CFG itself.  This is done in cfgexpand.c.  */     

static void
emit_case_dispatch_table (tree index_expr, tree index_type,
			  struct case_node *case_list, rtx default_label,
			  tree minval, tree maxval, tree range,
                          basic_block stmt_bb)
{
  int i, ncases;
  struct case_node *n;
  rtx *labelvec;
  rtx fallback_label = label_rtx (case_list->code_label);
  rtx table_label = gen_label_rtx ();
  bool has_gaps = false;
  edge default_edge = stmt_bb ? EDGE_SUCC(stmt_bb, 0) : NULL;
  int default_prob = default_edge ? default_edge->probability : 0;
  int base = get_outgoing_edge_probs (stmt_bb);
  bool try_with_tablejump = false;

  int new_default_prob = conditional_probability (default_prob,
                                                  base);

  if (! try_casesi (index_type, index_expr, minval, range,
		    table_label, default_label, fallback_label,
                    new_default_prob))
    {
      /* Index jumptables from zero for suitable values of minval to avoid
	 a subtraction.  For the rationale see:
	 "http://gcc.gnu.org/ml/gcc-patches/2001-10/msg01234.html".  */
      if (optimize_insn_for_speed_p ()
	  && compare_tree_int (minval, 0) > 0
	  && compare_tree_int (minval, 3) < 0)
	{
	  minval = build_int_cst (index_type, 0);
	  range = maxval;
          has_gaps = true;
	}
      try_with_tablejump = true;
    }

  /* Get table of labels to jump to, in order of case index.  */

  ncases = tree_low_cst (range, 0) + 1;
  labelvec = XALLOCAVEC (rtx, ncases);
  memset (labelvec, 0, ncases * sizeof (rtx));

  for (n = case_list; n; n = n->right)
    {
      /* Compute the low and high bounds relative to the minimum
	 value since that should fit in a HOST_WIDE_INT while the
	 actual values may not.  */
      HOST_WIDE_INT i_low
	= tree_low_cst (fold_build2 (MINUS_EXPR, index_type,
				     n->low, minval), 1);
      HOST_WIDE_INT i_high
	= tree_low_cst (fold_build2 (MINUS_EXPR, index_type,
				     n->high, minval), 1);
      HOST_WIDE_INT i;

      for (i = i_low; i <= i_high; i ++)
	labelvec[i]
	  = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
    }

  /* Fill in the gaps with the default.  We may have gaps at
     the beginning if we tried to avoid the minval subtraction,
     so substitute some label even if the default label was
     deemed unreachable.  */
  if (!default_label)
    default_label = fallback_label;
  for (i = 0; i < ncases; i++)
    if (labelvec[i] == 0)
      {
        has_gaps = true;
        labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
      }

  if (has_gaps)
    {
      /* There is at least one entry in the jump table that jumps
         to default label. The default label can either be reached
         through the indirect jump or the direct conditional jump
         before that. Split the probability of reaching the
         default label among these two jumps.  */
      new_default_prob = conditional_probability (default_prob/2,
                                                  base);
      default_prob /= 2;
      base -= default_prob;
    }
  else
    {
      base -= default_prob;
      default_prob = 0;
    }

  if (default_edge)
    default_edge->probability = default_prob;

  /* We have altered the probability of the default edge. So the probabilities
     of all other edges need to be adjusted so that it sums up to
     REG_BR_PROB_BASE.  */
  if (base)
    {
      edge e;
      edge_iterator ei;
      FOR_EACH_EDGE (e, ei, stmt_bb->succs)
        e->probability = GCOV_COMPUTE_SCALE (e->probability,  base);
    }

  if (try_with_tablejump)
    {
      bool ok = try_tablejump (index_type, index_expr, minval, range,
                               table_label, default_label, new_default_prob);
      gcc_assert (ok);
    }
  /* Output the table.  */
  emit_label (table_label);

  if (CASE_VECTOR_PC_RELATIVE || flag_pic)
    emit_jump_table_data (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
						 gen_rtx_LABEL_REF (Pmode,
								    table_label),
						 gen_rtvec_v (ncases, labelvec),
						 const0_rtx, const0_rtx));
  else
    emit_jump_table_data (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
					    gen_rtvec_v (ncases, labelvec)));

  /* Record no drop-through after the table.  */
  emit_barrier ();
}

/* Reset the aux field of all outgoing edges of basic block BB.  */

static inline void
reset_out_edges_aux (basic_block bb)
{
  edge e;
  edge_iterator ei;
  FOR_EACH_EDGE(e, ei, bb->succs)
    e->aux = (void *)0;
}

/* Compute the number of case labels that correspond to each outgoing edge of
   STMT. Record this information in the aux field of the edge.  */

static inline void
compute_cases_per_edge (gimple stmt)
{
  basic_block bb = gimple_bb (stmt);
  reset_out_edges_aux (bb);
  int ncases = gimple_switch_num_labels (stmt);
  for (int i = ncases - 1; i >= 1; --i)
    {
      tree elt = gimple_switch_label (stmt, i);
      tree lab = CASE_LABEL (elt);
      basic_block case_bb = label_to_block_fn (cfun, lab);
      edge case_edge = find_edge (bb, case_bb);
      case_edge->aux = (void *)((intptr_t)(case_edge->aux) + 1);
    }
}

/* Terminate a case (Pascal/Ada) or switch (C) statement
   in which ORIG_INDEX is the expression to be tested.
   If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
   type as given in the source before any compiler conversions.
   Generate the code to test it and jump to the right place.  */

void
expand_case (gimple stmt)
{
  tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
  rtx default_label = NULL_RTX;
  unsigned int count, uniq;
  int i;
  int ncases = gimple_switch_num_labels (stmt);
  tree index_expr = gimple_switch_index (stmt);
  tree index_type = TREE_TYPE (index_expr);
  tree elt;
  basic_block bb = gimple_bb (stmt);

  /* A list of case labels; it is first built as a list and it may then
     be rearranged into a nearly balanced binary tree.  */
  struct case_node *case_list = 0;

  /* A pool for case nodes.  */
  alloc_pool case_node_pool;

  /* An ERROR_MARK occurs for various reasons including invalid data type.
     ??? Can this still happen, with GIMPLE and all?  */
  if (index_type == error_mark_node)
    return;

  /* cleanup_tree_cfg removes all SWITCH_EXPR with their index
     expressions being INTEGER_CST.  */
  gcc_assert (TREE_CODE (index_expr) != INTEGER_CST);
  
  case_node_pool = create_alloc_pool ("struct case_node pool",
				      sizeof (struct case_node),
				      100);

  do_pending_stack_adjust ();

  /* Find the default case target label.  */
  default_label = label_rtx (CASE_LABEL (gimple_switch_default_label (stmt)));
  edge default_edge = EDGE_SUCC(bb, 0);
  int default_prob = default_edge->probability;

  /* Get upper and lower bounds of case values.  */
  elt = gimple_switch_label (stmt, 1);
  minval = fold_convert (index_type, CASE_LOW (elt));
  elt = gimple_switch_label (stmt, ncases - 1);
  if (CASE_HIGH (elt))
    maxval = fold_convert (index_type, CASE_HIGH (elt));
  else
    maxval = fold_convert (index_type, CASE_LOW (elt));

  /* Compute span of values.  */
  range = fold_build2 (MINUS_EXPR, index_type, maxval, minval);

  /* Listify the labels queue and gather some numbers to decide
     how to expand this switch().  */
  uniq = 0;
  count = 0;
  struct pointer_set_t *seen_labels = pointer_set_create ();
  compute_cases_per_edge (stmt);

  for (i = ncases - 1; i >= 1; --i)
    {
      elt = gimple_switch_label (stmt, i);
      tree low = CASE_LOW (elt);
      gcc_assert (low);
      tree high = CASE_HIGH (elt);
      gcc_assert (! high || tree_int_cst_lt (low, high));
      tree lab = CASE_LABEL (elt);

      /* Count the elements.
	 A range counts double, since it requires two compares.  */
      count++;
      if (high)
	count++;

      /* If we have not seen this label yet, then increase the
	 number of unique case node targets seen.  */
      if (!pointer_set_insert (seen_labels, lab))
	uniq++;

      /* The bounds on the case range, LOW and HIGH, have to be converted
	 to case's index type TYPE.  Note that the original type of the
	 case index in the source code is usually "lost" during
	 gimplification due to type promotion, but the case labels retain the
	 original type.  Make sure to drop overflow flags.  */
      low = fold_convert (index_type, low);
      if (TREE_OVERFLOW (low))
	low = build_int_cst_wide (index_type,
				  TREE_INT_CST_LOW (low),
				  TREE_INT_CST_HIGH (low));

      /* The canonical from of a case label in GIMPLE is that a simple case
	 has an empty CASE_HIGH.  For the casesi and tablejump expanders,
	 the back ends want simple cases to have high == low.  */
      if (! high)
	high = low;
      high = fold_convert (index_type, high);
      if (TREE_OVERFLOW (high))
	high = build_int_cst_wide (index_type,
				   TREE_INT_CST_LOW (high),
				   TREE_INT_CST_HIGH (high));

      basic_block case_bb = label_to_block_fn (cfun, lab);
      edge case_edge = find_edge (bb, case_bb);
      case_list = add_case_node (
          case_list, low, high, lab,
          case_edge->probability / (intptr_t)(case_edge->aux),
          case_node_pool);
    }
  pointer_set_destroy (seen_labels);
  reset_out_edges_aux (bb);

  /* cleanup_tree_cfg removes all SWITCH_EXPR with a single
     destination, such as one with a default case only.
     It also removes cases that are out of range for the switch
     type, so we should never get a zero here.  */
  gcc_assert (count > 0);

  rtx before_case = get_last_insn ();

  /* Decide how to expand this switch.
     The two options at this point are a dispatch table (casesi or
     tablejump) or a decision tree.  */

  if (expand_switch_as_decision_tree_p (range, uniq, count))
    emit_case_decision_tree (index_expr, index_type,
                             case_list, default_label,
                             default_prob);
  else
    emit_case_dispatch_table (index_expr, index_type,
			      case_list, default_label,
			      minval, maxval, range, bb);

  reorder_insns (NEXT_INSN (before_case), get_last_insn (), before_case);

  free_temp_slots ();
  free_alloc_pool (case_node_pool);
}

/* Expand the dispatch to a short decrement chain if there are few cases
   to dispatch to.  Likewise if neither casesi nor tablejump is available,
   or if flag_jump_tables is set.  Otherwise, expand as a casesi or a
   tablejump.  The index mode is always the mode of integer_type_node.
   Trap if no case matches the index.

   DISPATCH_INDEX is the index expression to switch on.  It should be a
   memory or register operand.
   
   DISPATCH_TABLE is a set of case labels.  The set should be sorted in
   ascending order, be contiguous, starting with value 0, and contain only
   single-valued case labels.  */

void
expand_sjlj_dispatch_table (rtx dispatch_index,
			    vec<tree> dispatch_table)
{
  tree index_type = integer_type_node;
  enum machine_mode index_mode = TYPE_MODE (index_type);

  int ncases = dispatch_table.length ();

  do_pending_stack_adjust ();
  rtx before_case = get_last_insn ();

  /* Expand as a decrement-chain if there are 5 or fewer dispatch
     labels.  This covers more than 98% of the cases in libjava,
     and seems to be a reasonable compromise between the "old way"
     of expanding as a decision tree or dispatch table vs. the "new
     way" with decrement chain or dispatch table.  */
  if (dispatch_table.length () <= 5
      || (!HAVE_casesi && !HAVE_tablejump)
      || !flag_jump_tables)
    {
      /* Expand the dispatch as a decrement chain:

	 "switch(index) {case 0: do_0; case 1: do_1; ...; case N: do_N;}"

	 ==>

	 if (index == 0) do_0; else index--;
	 if (index == 0) do_1; else index--;
	 ...
	 if (index == 0) do_N; else index--;

	 This is more efficient than a dispatch table on most machines.
	 The last "index--" is redundant but the code is trivially dead
	 and will be cleaned up by later passes.  */
      rtx index = copy_to_mode_reg (index_mode, dispatch_index);
      rtx zero = CONST0_RTX (index_mode);
      for (int i = 0; i < ncases; i++)
        {
	  tree elt = dispatch_table[i];
	  rtx lab = label_rtx (CASE_LABEL (elt));
	  do_jump_if_equal (index_mode, index, zero, lab, 0, -1);
	  force_expand_binop (index_mode, sub_optab,
			      index, CONST1_RTX (index_mode),
			      index, 0, OPTAB_DIRECT);
	}
    }
  else
    {
      /* Similar to expand_case, but much simpler.  */
      struct case_node *case_list = 0;
      alloc_pool case_node_pool = create_alloc_pool ("struct sjlj_case pool",
						     sizeof (struct case_node),
						     ncases);
      tree index_expr = make_tree (index_type, dispatch_index);
      tree minval = build_int_cst (index_type, 0);
      tree maxval = CASE_LOW (dispatch_table.last ());
      tree range = maxval;
      rtx default_label = gen_label_rtx ();

      for (int i = ncases - 1; i >= 0; --i)
	{
	  tree elt = dispatch_table[i];
	  tree low = CASE_LOW (elt);
	  tree lab = CASE_LABEL (elt);
	  case_list = add_case_node (case_list, low, low, lab, 0, case_node_pool);
	}

      emit_case_dispatch_table (index_expr, index_type,
				case_list, default_label,
				minval, maxval, range,
                                BLOCK_FOR_INSN (before_case));
      emit_label (default_label);
      free_alloc_pool (case_node_pool);
    }

  /* Dispatching something not handled?  Trap!  */
  expand_builtin_trap ();

  reorder_insns (NEXT_INSN (before_case), get_last_insn (), before_case);

  free_temp_slots ();
}


/* Take an ordered list of case nodes
   and transform them into a near optimal binary tree,
   on the assumption that any target code selection value is as
   likely as any other.

   The transformation is performed by splitting the ordered
   list into two equal sections plus a pivot.  The parts are
   then attached to the pivot as left and right branches.  Each
   branch is then transformed recursively.  */

static void
balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
{
  case_node_ptr np;

  np = *head;
  if (np)
    {
      int i = 0;
      int ranges = 0;
      case_node_ptr *npp;
      case_node_ptr left;

      /* Count the number of entries on branch.  Also count the ranges.  */

      while (np)
	{
	  if (!tree_int_cst_equal (np->low, np->high))
	    ranges++;

	  i++;
	  np = np->right;
	}

      if (i > 2)
	{
	  /* Split this list if it is long enough for that to help.  */
	  npp = head;
	  left = *npp;

	  /* If there are just three nodes, split at the middle one.  */
	  if (i == 3)
	    npp = &(*npp)->right;
	  else
	    {
	      /* Find the place in the list that bisects the list's total cost,
		 where ranges count as 2.
		 Here I gets half the total cost.  */
	      i = (i + ranges + 1) / 2;
	      while (1)
		{
		  /* Skip nodes while their cost does not reach that amount.  */
		  if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
		    i--;
		  i--;
		  if (i <= 0)
		    break;
		  npp = &(*npp)->right;
		}
	    }
	  *head = np = *npp;
	  *npp = 0;
	  np->parent = parent;
	  np->left = left;

	  /* Optimize each of the two split parts.  */
	  balance_case_nodes (&np->left, np);
	  balance_case_nodes (&np->right, np);
          np->subtree_prob = np->prob;
          np->subtree_prob += np->left->subtree_prob;
          np->subtree_prob += np->right->subtree_prob;
	}
      else
	{
	  /* Else leave this branch as one level,
	     but fill in `parent' fields.  */
	  np = *head;
	  np->parent = parent;
          np->subtree_prob = np->prob;
	  for (; np->right; np = np->right)
            {
	      np->right->parent = np;
              (*head)->subtree_prob += np->right->subtree_prob;
            }
	}
    }
}

/* Search the parent sections of the case node tree
   to see if a test for the lower bound of NODE would be redundant.
   INDEX_TYPE is the type of the index expression.

   The instructions to generate the case decision tree are
   output in the same order as nodes are processed so it is
   known that if a parent node checks the range of the current
   node minus one that the current node is bounded at its lower
   span.  Thus the test would be redundant.  */

static int
node_has_low_bound (case_node_ptr node, tree index_type)
{
  tree low_minus_one;
  case_node_ptr pnode;

  /* If the lower bound of this node is the lowest value in the index type,
     we need not test it.  */

  if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
    return 1;

  /* If this node has a left branch, the value at the left must be less
     than that at this node, so it cannot be bounded at the bottom and
     we need not bother testing any further.  */

  if (node->left)
    return 0;

  low_minus_one = fold_build2 (MINUS_EXPR, TREE_TYPE (node->low),
			       node->low,
			       build_int_cst (TREE_TYPE (node->low), 1));

  /* If the subtraction above overflowed, we can't verify anything.
     Otherwise, look for a parent that tests our value - 1.  */

  if (! tree_int_cst_lt (low_minus_one, node->low))
    return 0;

  for (pnode = node->parent; pnode; pnode = pnode->parent)
    if (tree_int_cst_equal (low_minus_one, pnode->high))
      return 1;

  return 0;
}

/* Search the parent sections of the case node tree
   to see if a test for the upper bound of NODE would be redundant.
   INDEX_TYPE is the type of the index expression.

   The instructions to generate the case decision tree are
   output in the same order as nodes are processed so it is
   known that if a parent node checks the range of the current
   node plus one that the current node is bounded at its upper
   span.  Thus the test would be redundant.  */

static int
node_has_high_bound (case_node_ptr node, tree index_type)
{
  tree high_plus_one;
  case_node_ptr pnode;

  /* If there is no upper bound, obviously no test is needed.  */

  if (TYPE_MAX_VALUE (index_type) == NULL)
    return 1;

  /* If the upper bound of this node is the highest value in the type
     of the index expression, we need not test against it.  */

  if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
    return 1;

  /* If this node has a right branch, the value at the right must be greater
     than that at this node, so it cannot be bounded at the top and
     we need not bother testing any further.  */

  if (node->right)
    return 0;

  high_plus_one = fold_build2 (PLUS_EXPR, TREE_TYPE (node->high),
			       node->high,
			       build_int_cst (TREE_TYPE (node->high), 1));

  /* If the addition above overflowed, we can't verify anything.
     Otherwise, look for a parent that tests our value + 1.  */

  if (! tree_int_cst_lt (node->high, high_plus_one))
    return 0;

  for (pnode = node->parent; pnode; pnode = pnode->parent)
    if (tree_int_cst_equal (high_plus_one, pnode->low))
      return 1;

  return 0;
}

/* Search the parent sections of the
   case node tree to see if both tests for the upper and lower
   bounds of NODE would be redundant.  */

static int
node_is_bounded (case_node_ptr node, tree index_type)
{
  return (node_has_low_bound (node, index_type)
	  && node_has_high_bound (node, index_type));
}


/* Emit step-by-step code to select a case for the value of INDEX.
   The thus generated decision tree follows the form of the
   case-node binary tree NODE, whose nodes represent test conditions.
   INDEX_TYPE is the type of the index of the switch.

   Care is taken to prune redundant tests from the decision tree
   by detecting any boundary conditions already checked by
   emitted rtx.  (See node_has_high_bound, node_has_low_bound
   and node_is_bounded, above.)

   Where the test conditions can be shown to be redundant we emit
   an unconditional jump to the target code.  As a further
   optimization, the subordinates of a tree node are examined to
   check for bounded nodes.  In this case conditional and/or
   unconditional jumps as a result of the boundary check for the
   current node are arranged to target the subordinates associated
   code for out of bound conditions on the current node.

   We can assume that when control reaches the code generated here,
   the index value has already been compared with the parents
   of this node, and determined to be on the same side of each parent
   as this node is.  Thus, if this node tests for the value 51,
   and a parent tested for 52, we don't need to consider
   the possibility of a value greater than 51.  If another parent
   tests for the value 50, then this node need not test anything.  */

static void
emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
		 int default_prob, tree index_type)
{
  /* If INDEX has an unsigned type, we must make unsigned branches.  */
  int unsignedp = TYPE_UNSIGNED (index_type);
  int probability;
  int prob = node->prob, subtree_prob = node->subtree_prob;
  enum machine_mode mode = GET_MODE (index);
  enum machine_mode imode = TYPE_MODE (index_type);

  /* Handle indices detected as constant during RTL expansion.  */
  if (mode == VOIDmode)
    mode = imode;

  /* See if our parents have already tested everything for us.
     If they have, emit an unconditional jump for this node.  */
  if (node_is_bounded (node, index_type))
    emit_jump (label_rtx (node->code_label));

  else if (tree_int_cst_equal (node->low, node->high))
    {
      probability = conditional_probability (prob, subtree_prob + default_prob);
      /* Node is single valued.  First see if the index expression matches
	 this node and then check our children, if any.  */
      do_jump_if_equal (mode, index,
			convert_modes (mode, imode,
				       expand_normal (node->low),
				       unsignedp),
			label_rtx (node->code_label), unsignedp, probability);
      /* Since this case is taken at this point, reduce its weight from
         subtree_weight.  */
      subtree_prob -= prob;
      if (node->right != 0 && node->left != 0)
	{
	  /* This node has children on both sides.
	     Dispatch to one side or the other
	     by comparing the index value with this node's value.
	     If one subtree is bounded, check that one first,
	     so we can avoid real branches in the tree.  */

	  if (node_is_bounded (node->right, index_type))
	    {
              probability = conditional_probability (
                  node->right->prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       label_rtx (node->right->code_label),
                                       probability);
	      emit_case_nodes (index, node->left, default_label, default_prob,
                               index_type);
	    }

	  else if (node_is_bounded (node->left, index_type))
	    {
              probability = conditional_probability (
                  node->left->prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       LT, NULL_RTX, mode, unsignedp,
				       label_rtx (node->left->code_label),
                                       probability);
	      emit_case_nodes (index, node->right, default_label, default_prob, index_type);
	    }

	  /* If both children are single-valued cases with no
	     children, finish up all the work.  This way, we can save
	     one ordered comparison.  */
	  else if (tree_int_cst_equal (node->right->low, node->right->high)
		   && node->right->left == 0
		   && node->right->right == 0
		   && tree_int_cst_equal (node->left->low, node->left->high)
		   && node->left->left == 0
		   && node->left->right == 0)
	    {
	      /* Neither node is bounded.  First distinguish the two sides;
		 then emit the code for one side at a time.  */

	      /* See if the value matches what the right hand side
		 wants.  */
              probability = conditional_probability (
                  node->right->prob,
                  subtree_prob + default_prob);
	      do_jump_if_equal (mode, index,
				convert_modes (mode, imode,
					       expand_normal (node->right->low),
					       unsignedp),
				label_rtx (node->right->code_label),
				unsignedp, probability);

	      /* See if the value matches what the left hand side
		 wants.  */
              probability = conditional_probability (
                  node->left->prob,
                  subtree_prob + default_prob);
	      do_jump_if_equal (mode, index,
				convert_modes (mode, imode,
					       expand_normal (node->left->low),
					       unsignedp),
				label_rtx (node->left->code_label),
				unsignedp, probability);
	    }

	  else
	    {
	      /* Neither node is bounded.  First distinguish the two sides;
		 then emit the code for one side at a time.  */

	      tree test_label
		= build_decl (curr_insn_location (),
			      LABEL_DECL, NULL_TREE, NULL_TREE);

              /* The default label could be reached either through the right
                 subtree or the left subtree. Divide the probability
                 equally.  */
              probability = conditional_probability (
                  node->right->subtree_prob + default_prob/2,
                  subtree_prob + default_prob);
	      /* See if the value is on the right.  */
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       label_rtx (test_label),
                                       probability);
              default_prob /= 2;

	      /* Value must be on the left.
		 Handle the left-hand subtree.  */
	      emit_case_nodes (index, node->left, default_label, default_prob, index_type);
	      /* If left-hand subtree does nothing,
		 go to default.  */
	      if (default_label)
	        emit_jump (default_label);

	      /* Code branches here for the right-hand subtree.  */
	      expand_label (test_label);
	      emit_case_nodes (index, node->right, default_label, default_prob, index_type);
	    }
	}

      else if (node->right != 0 && node->left == 0)
	{
	  /* Here we have a right child but no left so we issue a conditional
	     branch to default and process the right child.

	     Omit the conditional branch to default if the right child
	     does not have any children and is single valued; it would
	     cost too much space to save so little time.  */

	  if (node->right->right || node->right->left
	      || !tree_int_cst_equal (node->right->low, node->right->high))
	    {
	      if (!node_has_low_bound (node, index_type))
		{
                  probability = conditional_probability (
                      default_prob/2,
                      subtree_prob + default_prob);
		  emit_cmp_and_jump_insns (index,
					   convert_modes
					   (mode, imode,
					    expand_normal (node->high),
					    unsignedp),
					   LT, NULL_RTX, mode, unsignedp,
					   default_label,
                                           probability);
                  default_prob /= 2;
		}

	      emit_case_nodes (index, node->right, default_label, default_prob, index_type);
	    }
	  else
            {
              probability = conditional_probability (
                  node->right->subtree_prob,
                  subtree_prob + default_prob);
	      /* We cannot process node->right normally
	         since we haven't ruled out the numbers less than
	         this node's value.  So handle node->right explicitly.  */
	      do_jump_if_equal (mode, index,
			        convert_modes
			        (mode, imode,
			         expand_normal (node->right->low),
			         unsignedp),
			        label_rtx (node->right->code_label), unsignedp, probability);
            }
	  }

      else if (node->right == 0 && node->left != 0)
	{
	  /* Just one subtree, on the left.  */
	  if (node->left->left || node->left->right
	      || !tree_int_cst_equal (node->left->low, node->left->high))
	    {
	      if (!node_has_high_bound (node, index_type))
		{
                  probability = conditional_probability (
                      default_prob/2,
                      subtree_prob + default_prob);
		  emit_cmp_and_jump_insns (index,
					   convert_modes
					   (mode, imode,
					    expand_normal (node->high),
					    unsignedp),
					   GT, NULL_RTX, mode, unsignedp,
					   default_label,
                                           probability);
                  default_prob /= 2;
		}

	      emit_case_nodes (index, node->left, default_label,
                               default_prob, index_type);
	    }
	  else
            {
              probability = conditional_probability (
                  node->left->subtree_prob,
                  subtree_prob + default_prob);
	      /* We cannot process node->left normally
	         since we haven't ruled out the numbers less than
	         this node's value.  So handle node->left explicitly.  */
	      do_jump_if_equal (mode, index,
			        convert_modes
			        (mode, imode,
			         expand_normal (node->left->low),
			         unsignedp),
			        label_rtx (node->left->code_label), unsignedp, probability);
            }
	}
    }
  else
    {
      /* Node is a range.  These cases are very similar to those for a single
	 value, except that we do not start by testing whether this node
	 is the one to branch to.  */

      if (node->right != 0 && node->left != 0)
	{
	  /* Node has subtrees on both sides.
	     If the right-hand subtree is bounded,
	     test for it first, since we can go straight there.
	     Otherwise, we need to make a branch in the control structure,
	     then handle the two subtrees.  */
	  tree test_label = 0;

	  if (node_is_bounded (node->right, index_type))
            {
	      /* Right hand node is fully bounded so we can eliminate any
	         testing and branch directly to the target code.  */
              probability = conditional_probability (
                  node->right->subtree_prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
				        expand_normal (node->high),
				        unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       label_rtx (node->right->code_label),
                                       probability);
            }
	  else
	    {
	      /* Right hand node requires testing.
		 Branch to a label where we will handle it later.  */

	      test_label = build_decl (curr_insn_location (),
				       LABEL_DECL, NULL_TREE, NULL_TREE);
              probability = conditional_probability (
                  node->right->subtree_prob + default_prob/2,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       label_rtx (test_label),
                                       probability);
              default_prob /= 2;
	    }

	  /* Value belongs to this node or to the left-hand subtree.  */

          probability = conditional_probability (
              prob,
              subtree_prob + default_prob);
	  emit_cmp_and_jump_insns (index,
				   convert_modes
				   (mode, imode,
				    expand_normal (node->low),
				    unsignedp),
				   GE, NULL_RTX, mode, unsignedp,
				   label_rtx (node->code_label),
                                   probability);

	  /* Handle the left-hand subtree.  */
	  emit_case_nodes (index, node->left, default_label, default_prob, index_type);

	  /* If right node had to be handled later, do that now.  */

	  if (test_label)
	    {
	      /* If the left-hand subtree fell through,
		 don't let it fall into the right-hand subtree.  */
	      if (default_label)
		emit_jump (default_label);

	      expand_label (test_label);
	      emit_case_nodes (index, node->right, default_label, default_prob, index_type);
	    }
	}

      else if (node->right != 0 && node->left == 0)
	{
	  /* Deal with values to the left of this node,
	     if they are possible.  */
	  if (!node_has_low_bound (node, index_type))
	    {
              probability = conditional_probability (
                  default_prob/2,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->low),
					unsignedp),
				       LT, NULL_RTX, mode, unsignedp,
				       default_label,
                                       probability);
              default_prob /= 2;
	    }

	  /* Value belongs to this node or to the right-hand subtree.  */

          probability = conditional_probability (
              prob,
              subtree_prob + default_prob);
	  emit_cmp_and_jump_insns (index,
				   convert_modes
				   (mode, imode,
				    expand_normal (node->high),
				    unsignedp),
				   LE, NULL_RTX, mode, unsignedp,
				   label_rtx (node->code_label),
                                   probability);

	  emit_case_nodes (index, node->right, default_label, default_prob, index_type);
	}

      else if (node->right == 0 && node->left != 0)
	{
	  /* Deal with values to the right of this node,
	     if they are possible.  */
	  if (!node_has_high_bound (node, index_type))
	    {
              probability = conditional_probability (
                  default_prob/2,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       default_label,
                                       probability);
              default_prob /= 2;
	    }

	  /* Value belongs to this node or to the left-hand subtree.  */

          probability = conditional_probability (
              prob,
              subtree_prob + default_prob);
	  emit_cmp_and_jump_insns (index,
				   convert_modes
				   (mode, imode,
				    expand_normal (node->low),
				    unsignedp),
				   GE, NULL_RTX, mode, unsignedp,
				   label_rtx (node->code_label),
                                   probability);

	  emit_case_nodes (index, node->left, default_label, default_prob, index_type);
	}

      else
	{
	  /* Node has no children so we check low and high bounds to remove
	     redundant tests.  Only one of the bounds can exist,
	     since otherwise this node is bounded--a case tested already.  */
	  int high_bound = node_has_high_bound (node, index_type);
	  int low_bound = node_has_low_bound (node, index_type);

	  if (!high_bound && low_bound)
	    {
              probability = conditional_probability (
                  default_prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->high),
					unsignedp),
				       GT, NULL_RTX, mode, unsignedp,
				       default_label,
                                       probability);
	    }

	  else if (!low_bound && high_bound)
	    {
              probability = conditional_probability (
                  default_prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (index,
				       convert_modes
				       (mode, imode,
					expand_normal (node->low),
					unsignedp),
				       LT, NULL_RTX, mode, unsignedp,
				       default_label,
                                       probability);
	    }
	  else if (!low_bound && !high_bound)
	    {
	      /* Widen LOW and HIGH to the same width as INDEX.  */
	      tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
	      tree low = build1 (CONVERT_EXPR, type, node->low);
	      tree high = build1 (CONVERT_EXPR, type, node->high);
	      rtx low_rtx, new_index, new_bound;

	      /* Instead of doing two branches, emit one unsigned branch for
		 (index-low) > (high-low).  */
	      low_rtx = expand_expr (low, NULL_RTX, mode, EXPAND_NORMAL);
	      new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
					       NULL_RTX, unsignedp,
					       OPTAB_WIDEN);
	      new_bound = expand_expr (fold_build2 (MINUS_EXPR, type,
						    high, low),
				       NULL_RTX, mode, EXPAND_NORMAL);

              probability = conditional_probability (
                  default_prob,
                  subtree_prob + default_prob);
	      emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
				       mode, 1, default_label, probability);
	    }

	  emit_jump (label_rtx (node->code_label));
	}
    }
}