aboutsummaryrefslogtreecommitdiffstats
path: root/recipes-devtools/gcc/gcc-4.5/linaro/gcc-4.5-linaro-r99306.patch
blob: 423cd56528ff540caf9ce42f00ec951b746b50b2 (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
2010-07-10  Sandra Loosemore  <sandra@codesourcery.com>

	Backport from mainline:

	2010-05-08  Sandra Loosemore  <sandra@codesourcery.com>

	PR middle-end/28685

	gcc/
	* tree-ssa-reassoc.c (eliminate_redundant_comparison): New function.
	(optimize_ops_list): Call it.

	gcc/testsuite/
	* gcc.dg/pr28685-1.c: New file.

	2010-06-08  Sandra Loosemore  <sandra@codesourcery.com>

	PR tree-optimization/39874
	PR middle-end/28685

	gcc/
	* gimple.h (maybe_fold_and_comparisons, maybe_fold_or_comparisons):
	Declare.
	* gimple-fold.c (canonicalize_bool, same_bool_comparison_p,
	same_bool_result_p): New.
	(and_var_with_comparison, and_var_with_comparison_1,
	and_comparisons_1, and_comparisons, maybe_fold_and_comparisons): New.
	(or_var_with_comparison, or_var_with_comparison_1,
	or_comparisons_1, or_comparisons, maybe_fold_or_comparisons): New.
	* tree-ssa-reassoc.c (eliminate_redundant_comparison): Use
	maybe_fold_and_comparisons or maybe_fold_or_comparisons instead
	of combine_comparisons.
	* tree-ssa-ifcombine.c (ifcombine_ifandif, ifcombine_iforif): Likewise.

	gcc/testsuite/
	* gcc.dg/pr39874.c: New file.

 2010-07-10  Yao Qi  <yao@codesourcery.com>
 
 	Merge from Sourcery G++ 4.4:

=== modified file 'gcc/gimple.h'
--- old/gcc/gimple.h	2010-04-02 18:54:46 +0000
+++ new/gcc/gimple.h	2010-07-30 13:21:51 +0000
@@ -4743,4 +4743,9 @@
 
 extern void dump_gimple_statistics (void);
 
+extern tree maybe_fold_and_comparisons (enum tree_code, tree, tree, 
+					enum tree_code, tree, tree);
+extern tree maybe_fold_or_comparisons (enum tree_code, tree, tree,
+				       enum tree_code, tree, tree);
+
 #endif  /* GCC_GIMPLE_H */

=== added file 'gcc/testsuite/gcc.dg/pr28685-1.c'
--- old/gcc/testsuite/gcc.dg/pr28685-1.c	1970-01-01 00:00:00 +0000
+++ new/gcc/testsuite/gcc.dg/pr28685-1.c	2010-07-30 13:21:51 +0000
@@ -0,0 +1,50 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" }  */
+
+/* Should produce <=.  */
+int test1 (int a, int b)
+{
+  return (a < b || a == b);
+}
+
+/* Should produce <=.  */
+int test2 (int a, int b)
+{
+  int lt = a < b;
+  int eq = a == b;
+
+  return (lt || eq);
+}
+
+/* Should produce <= (just deleting redundant test).  */
+int test3 (int a, int b)
+{
+  int lt = a <= b;
+  int eq = a == b;
+
+  return (lt || eq);
+}
+
+/* Should produce <= (operands reversed to test the swap logic).  */
+int test4 (int a, int b)
+{
+  int lt = a < b;
+  int eq = b == a;
+
+  return (lt || eq);
+}
+
+/* Should produce constant 0.  */
+int test5 (int a, int b)
+{
+  int lt = a < b;
+  int eq = a == b;
+
+  return (lt && eq);
+}
+
+/* { dg-final { scan-tree-dump-times " <= " 4 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not " < " "optimized" } } */
+/* { dg-final { scan-tree-dump-not " == " "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

=== added file 'gcc/testsuite/gcc.dg/pr39874.c'
--- old/gcc/testsuite/gcc.dg/pr39874.c	1970-01-01 00:00:00 +0000
+++ new/gcc/testsuite/gcc.dg/pr39874.c	2010-07-30 13:21:51 +0000
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" }  */
+
+extern void func();
+
+void test1(char *signature)
+{
+  char ch = signature[0];
+  if (ch == 15 || ch == 3)
+  {
+    if (ch == 15) func();
+  }
+}
+
+
+void test2(char *signature)
+{
+  char ch = signature[0];
+  if (ch == 15 || ch == 3)
+  {
+    if (ch > 14) func();
+  }
+}
+
+/* { dg-final { scan-tree-dump-times " == 15" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-not " == 3" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
+
+

=== modified file 'gcc/tree-ssa-ccp.c'
--- old/gcc/tree-ssa-ccp.c	2010-04-02 15:50:04 +0000
+++ new/gcc/tree-ssa-ccp.c	2010-07-30 13:21:51 +0000
@@ -3176,6 +3176,1056 @@
   return changed;
 }
 
+/* Canonicalize and possibly invert the boolean EXPR; return NULL_TREE 
+   if EXPR is null or we don't know how.
+   If non-null, the result always has boolean type.  */
+
+static tree
+canonicalize_bool (tree expr, bool invert)
+{
+  if (!expr)
+    return NULL_TREE;
+  else if (invert)
+    {
+      if (integer_nonzerop (expr))
+	return boolean_false_node;
+      else if (integer_zerop (expr))
+	return boolean_true_node;
+      else if (TREE_CODE (expr) == SSA_NAME)
+	return fold_build2 (EQ_EXPR, boolean_type_node, expr,
+			    build_int_cst (TREE_TYPE (expr), 0));
+      else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
+	return fold_build2 (invert_tree_comparison (TREE_CODE (expr), false),
+			    boolean_type_node,
+			    TREE_OPERAND (expr, 0),
+			    TREE_OPERAND (expr, 1));
+      else
+	return NULL_TREE;
+    }
+  else
+    {
+      if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
+	return expr;
+      if (integer_nonzerop (expr))
+	return boolean_true_node;
+      else if (integer_zerop (expr))
+	return boolean_false_node;
+      else if (TREE_CODE (expr) == SSA_NAME)
+	return fold_build2 (NE_EXPR, boolean_type_node, expr,
+			    build_int_cst (TREE_TYPE (expr), 0));
+      else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
+	return fold_build2 (TREE_CODE (expr),
+			    boolean_type_node,
+			    TREE_OPERAND (expr, 0),
+			    TREE_OPERAND (expr, 1));
+      else
+	return NULL_TREE;
+    }
+}
+
+/* Check to see if a boolean expression EXPR is logically equivalent to the
+   comparison (OP1 CODE OP2).  Check for various identities involving
+   SSA_NAMEs.  */
+
+static bool
+same_bool_comparison_p (const_tree expr, enum tree_code code,
+			const_tree op1, const_tree op2)
+{
+  gimple s;
+
+  /* The obvious case.  */
+  if (TREE_CODE (expr) == code
+      && operand_equal_p (TREE_OPERAND (expr, 0), op1, 0)
+      && operand_equal_p (TREE_OPERAND (expr, 1), op2, 0))
+    return true;
+
+  /* Check for comparing (name, name != 0) and the case where expr
+     is an SSA_NAME with a definition matching the comparison.  */
+  if (TREE_CODE (expr) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
+    {
+      if (operand_equal_p (expr, op1, 0))
+	return ((code == NE_EXPR && integer_zerop (op2))
+		|| (code == EQ_EXPR && integer_nonzerop (op2)));
+      s = SSA_NAME_DEF_STMT (expr);
+      if (is_gimple_assign (s)
+	  && gimple_assign_rhs_code (s) == code
+	  && operand_equal_p (gimple_assign_rhs1 (s), op1, 0)
+	  && operand_equal_p (gimple_assign_rhs2 (s), op2, 0))
+	return true;
+    }
+
+  /* If op1 is of the form (name != 0) or (name == 0), and the definition
+     of name is a comparison, recurse.  */
+  if (TREE_CODE (op1) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (op1)) == BOOLEAN_TYPE)
+    {
+      s = SSA_NAME_DEF_STMT (op1);
+      if (is_gimple_assign (s)
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison)
+	{
+	  enum tree_code c = gimple_assign_rhs_code (s);
+	  if ((c == NE_EXPR && integer_zerop (op2))
+	      || (c == EQ_EXPR && integer_nonzerop (op2)))
+	    return same_bool_comparison_p (expr, c,
+					   gimple_assign_rhs1 (s),
+					   gimple_assign_rhs2 (s));
+	  if ((c == EQ_EXPR && integer_zerop (op2))
+	      || (c == NE_EXPR && integer_nonzerop (op2)))
+	    return same_bool_comparison_p (expr,
+					   invert_tree_comparison (c, false),
+					   gimple_assign_rhs1 (s),
+					   gimple_assign_rhs2 (s));
+	}
+    }
+  return false;
+}
+
+/* Check to see if two boolean expressions OP1 and OP2 are logically
+   equivalent.  */
+
+static bool
+same_bool_result_p (const_tree op1, const_tree op2)
+{
+  /* Simple cases first.  */
+  if (operand_equal_p (op1, op2, 0))
+    return true;
+
+  /* Check the cases where at least one of the operands is a comparison.
+     These are a bit smarter than operand_equal_p in that they apply some
+     identifies on SSA_NAMEs.  */
+  if (TREE_CODE_CLASS (TREE_CODE (op2)) == tcc_comparison
+      && same_bool_comparison_p (op1, TREE_CODE (op2),
+				 TREE_OPERAND (op2, 0),
+				 TREE_OPERAND (op2, 1)))
+    return true;
+  if (TREE_CODE_CLASS (TREE_CODE (op1)) == tcc_comparison
+      && same_bool_comparison_p (op2, TREE_CODE (op1),
+				 TREE_OPERAND (op1, 0),
+				 TREE_OPERAND (op1, 1)))
+    return true;
+
+  /* Default case.  */
+  return false;
+}
+
+/* Forward declarations for some mutually recursive functions.  */
+
+static tree
+and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		   enum tree_code code2, tree op2a, tree op2b);
+static tree
+and_var_with_comparison (tree var, bool invert,
+			 enum tree_code code2, tree op2a, tree op2b);
+static tree
+and_var_with_comparison_1 (gimple stmt, 
+			   enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		  enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_var_with_comparison (tree var, bool invert,
+			enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_var_with_comparison_1 (gimple stmt, 
+			  enum tree_code code2, tree op2a, tree op2b);
+
+/* Helper function for and_comparisons_1:  try to simplify the AND of the
+   ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
+   If INVERT is true, invert the value of the VAR before doing the AND.
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+and_var_with_comparison (tree var, bool invert,
+			 enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t;
+  gimple stmt = SSA_NAME_DEF_STMT (var);
+
+  /* We can only deal with variables whose definitions are assignments.  */
+  if (!is_gimple_assign (stmt))
+    return NULL_TREE;
+  
+  /* If we have an inverted comparison, apply DeMorgan's law and rewrite
+     !var AND (op2a code2 op2b) => !(var OR !(op2a code2 op2b))
+     Then we only have to consider the simpler non-inverted cases.  */
+  if (invert)
+    t = or_var_with_comparison_1 (stmt, 
+				  invert_tree_comparison (code2, false),
+				  op2a, op2b);
+  else
+    t = and_var_with_comparison_1 (stmt, code2, op2a, op2b);
+  return canonicalize_bool (t, invert);
+}
+
+/* Try to simplify the AND of the ssa variable defined by the assignment
+   STMT with the comparison specified by (OP2A CODE2 OP2B).
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+and_var_with_comparison_1 (gimple stmt,
+			   enum tree_code code2, tree op2a, tree op2b)
+{
+  tree var = gimple_assign_lhs (stmt);
+  tree true_test_var = NULL_TREE;
+  tree false_test_var = NULL_TREE;
+  enum tree_code innercode = gimple_assign_rhs_code (stmt);
+
+  /* Check for identities like (var AND (var == 0)) => false.  */
+  if (TREE_CODE (op2a) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
+    {
+      if ((code2 == NE_EXPR && integer_zerop (op2b))
+	  || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
+	{
+	  true_test_var = op2a;
+	  if (var == true_test_var)
+	    return var;
+	}
+      else if ((code2 == EQ_EXPR && integer_zerop (op2b))
+	       || (code2 == NE_EXPR && integer_nonzerop (op2b)))
+	{
+	  false_test_var = op2a;
+	  if (var == false_test_var)
+	    return boolean_false_node;
+	}
+    }
+
+  /* If the definition is a comparison, recurse on it.  */
+  if (TREE_CODE_CLASS (innercode) == tcc_comparison)
+    {
+      tree t = and_comparisons_1 (innercode,
+				  gimple_assign_rhs1 (stmt),
+				  gimple_assign_rhs2 (stmt),
+				  code2,
+				  op2a,
+				  op2b);
+      if (t)
+	return t;
+    }
+
+  /* If the definition is an AND or OR expression, we may be able to
+     simplify by reassociating.  */
+  if (innercode == TRUTH_AND_EXPR
+      || innercode == TRUTH_OR_EXPR
+      || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
+	  && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
+    {
+      tree inner1 = gimple_assign_rhs1 (stmt);
+      tree inner2 = gimple_assign_rhs2 (stmt);
+      gimple s;
+      tree t;
+      tree partial = NULL_TREE;
+      bool is_and = (innercode == TRUTH_AND_EXPR || innercode == BIT_AND_EXPR);
+      
+      /* Check for boolean identities that don't require recursive examination
+	 of inner1/inner2:
+	 inner1 AND (inner1 AND inner2) => inner1 AND inner2 => var
+	 inner1 AND (inner1 OR inner2) => inner1
+	 !inner1 AND (inner1 AND inner2) => false
+	 !inner1 AND (inner1 OR inner2) => !inner1 AND inner2
+         Likewise for similar cases involving inner2.  */
+      if (inner1 == true_test_var)
+	return (is_and ? var : inner1);
+      else if (inner2 == true_test_var)
+	return (is_and ? var : inner2);
+      else if (inner1 == false_test_var)
+	return (is_and
+		? boolean_false_node
+		: and_var_with_comparison (inner2, false, code2, op2a, op2b));
+      else if (inner2 == false_test_var)
+	return (is_and
+		? boolean_false_node
+		: and_var_with_comparison (inner1, false, code2, op2a, op2b));
+
+      /* Next, redistribute/reassociate the AND across the inner tests.
+	 Compute the first partial result, (inner1 AND (op2a code op2b))  */
+      if (TREE_CODE (inner1) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
+					      gimple_assign_rhs1 (s),
+					      gimple_assign_rhs2 (s),
+					      code2, op2a, op2b)))
+	{
+	  /* Handle the AND case, where we are reassociating:
+	     (inner1 AND inner2) AND (op2a code2 op2b)
+	     => (t AND inner2)
+	     If the partial result t is a constant, we win.  Otherwise
+	     continue on to try reassociating with the other inner test.  */
+	  if (is_and)
+	    {
+	      if (integer_onep (t))
+		return inner2;
+	      else if (integer_zerop (t))
+		return boolean_false_node;
+	    }
+
+	  /* Handle the OR case, where we are redistributing:
+	     (inner1 OR inner2) AND (op2a code2 op2b)
+	     => (t OR (inner2 AND (op2a code2 op2b)))  */
+	  else
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else
+		/* Save partial result for later.  */
+		partial = t;
+	    }
+	}
+      
+      /* Compute the second partial result, (inner2 AND (op2a code op2b)) */
+      if (TREE_CODE (inner2) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
+					      gimple_assign_rhs1 (s),
+					      gimple_assign_rhs2 (s),
+					      code2, op2a, op2b)))
+	{
+	  /* Handle the AND case, where we are reassociating:
+	     (inner1 AND inner2) AND (op2a code2 op2b)
+	     => (inner1 AND t)  */
+	  if (is_and)
+	    {
+	      if (integer_onep (t))
+		return inner1;
+	      else if (integer_zerop (t))
+		return boolean_false_node;
+	    }
+
+	  /* Handle the OR case. where we are redistributing:
+	     (inner1 OR inner2) AND (op2a code2 op2b)
+	     => (t OR (inner1 AND (op2a code2 op2b)))
+	     => (t OR partial)  */
+	  else
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else if (partial)
+		{
+		  /* We already got a simplification for the other
+		     operand to the redistributed OR expression.  The
+		     interesting case is when at least one is false.
+		     Or, if both are the same, we can apply the identity
+		     (x OR x) == x.  */
+		  if (integer_zerop (partial))
+		    return t;
+		  else if (integer_zerop (t))
+		    return partial;
+		  else if (same_bool_result_p (t, partial))
+		    return t;
+		}
+	    }
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the AND of two comparisons defined by
+   (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
+   If this can be done without constructing an intermediate value,
+   return the resulting tree; otherwise NULL_TREE is returned.
+   This function is deliberately asymmetric as it recurses on SSA_DEFs
+   in the first comparison but not the second.  */
+
+static tree
+and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		   enum tree_code code2, tree op2a, tree op2b)
+{
+  /* First check for ((x CODE1 y) AND (x CODE2 y)).  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && operand_equal_p (op1b, op2b, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ANDIF_EXPR, code1, code2,
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* Likewise the swapped case of the above.  */
+  if (operand_equal_p (op1a, op2b, 0)
+      && operand_equal_p (op1b, op2a, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ANDIF_EXPR, code1,
+				    swap_tree_comparison (code2),
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* If both comparisons are of the same value against constants, we might
+     be able to merge them.  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && TREE_CODE (op1b) == INTEGER_CST
+      && TREE_CODE (op2b) == INTEGER_CST)
+    {
+      int cmp = tree_int_cst_compare (op1b, op2b);
+
+      /* If we have (op1a == op1b), we should either be able to
+	 return that or FALSE, depending on whether the constant op1b
+	 also satisfies the other comparison against op2b.  */
+      if (code1 == EQ_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	      else
+		return boolean_false_node;
+	    }
+	}
+      /* Likewise if the second comparison is an == comparison.  */
+      else if (code2 == EQ_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	      else
+		return boolean_false_node;
+	    }
+	}
+
+      /* Same business with inequality tests.  */
+      else if (code1 == NE_EXPR)
+	{
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp != 0); break;
+	    case NE_EXPR: val = (cmp == 0); break;
+	    case LT_EXPR: val = (cmp >= 0); break;
+	    case GT_EXPR: val = (cmp <= 0); break;
+	    case LE_EXPR: val = (cmp > 0); break;
+	    case GE_EXPR: val = (cmp < 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+      else if (code2 == NE_EXPR)
+	{
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp <= 0); break;
+	    case GT_EXPR: val = (cmp >= 0); break;
+	    case LE_EXPR: val = (cmp < 0); break;
+	    case GE_EXPR: val = (cmp > 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Chose the more restrictive of two < or <= comparisons.  */
+      else if ((code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	{
+	  if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	  else
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+
+      /* Likewise chose the more restrictive of two > or >= comparisons.  */
+      else if ((code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	{
+	  if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	  else
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+
+      /* Check for singleton ranges.  */
+      else if (cmp == 0
+	       && ((code1 == LE_EXPR && code2 == GE_EXPR)
+		   || (code1 == GE_EXPR && code2 == LE_EXPR)))
+	return fold_build2 (EQ_EXPR, boolean_type_node, op1a, op2b);
+
+      /* Check for disjoint ranges. */
+      else if (cmp <= 0
+	       && (code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	return boolean_false_node;
+      else if (cmp >= 0
+	       && (code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	return boolean_false_node;
+    }
+
+  /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
+     NAME's definition is a truth value.  See if there are any simplifications
+     that can be done against the NAME's definition.  */
+  if (TREE_CODE (op1a) == SSA_NAME
+      && (code1 == NE_EXPR || code1 == EQ_EXPR)
+      && (integer_zerop (op1b) || integer_onep (op1b)))
+    {
+      bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
+		     || (code1 == NE_EXPR && integer_onep (op1b)));
+      gimple stmt = SSA_NAME_DEF_STMT (op1a);
+      switch (gimple_code (stmt))
+	{
+	case GIMPLE_ASSIGN:
+	  /* Try to simplify by copy-propagating the definition.  */
+	  return and_var_with_comparison (op1a, invert, code2, op2a, op2b);
+
+	case GIMPLE_PHI:
+	  /* If every argument to the PHI produces the same result when
+	     ANDed with the second comparison, we win.
+	     Do not do this unless the type is bool since we need a bool
+	     result here anyway.  */
+	  if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
+	    {
+	      tree result = NULL_TREE;
+	      unsigned i;
+	      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+		{
+		  tree arg = gimple_phi_arg_def (stmt, i);
+		  
+		  /* If this PHI has itself as an argument, ignore it.
+		     If all the other args produce the same result,
+		     we're still OK.  */
+		  if (arg == gimple_phi_result (stmt))
+		    continue;
+		  else if (TREE_CODE (arg) == INTEGER_CST)
+		    {
+		      if (invert ? integer_nonzerop (arg) : integer_zerop (arg))
+			{
+			  if (!result)
+			    result = boolean_false_node;
+			  else if (!integer_zerop (result))
+			    return NULL_TREE;
+			}
+		      else if (!result)
+			result = fold_build2 (code2, boolean_type_node,
+					      op2a, op2b);
+		      else if (!same_bool_comparison_p (result,
+							code2, op2a, op2b))
+			return NULL_TREE;
+		    }
+		  else if (TREE_CODE (arg) == SSA_NAME)
+		    {
+		      tree temp = and_var_with_comparison (arg, invert,
+							   code2, op2a, op2b);
+		      if (!temp)
+			return NULL_TREE;
+		      else if (!result)
+			result = temp;
+		      else if (!same_bool_result_p (result, temp))
+			return NULL_TREE;
+		    }
+		  else
+		    return NULL_TREE;
+		}
+	      return result;
+	    }
+
+	default:
+	  break;
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the AND of two comparisons, specified by
+   (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
+   If this can be simplified to a single expression (without requiring
+   introducing more SSA variables to hold intermediate values),
+   return the resulting tree.  Otherwise return NULL_TREE.
+   If the result expression is non-null, it has boolean type.  */
+
+tree
+maybe_fold_and_comparisons (enum tree_code code1, tree op1a, tree op1b,
+			    enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t = and_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
+  if (t)
+    return t;
+  else
+    return and_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
+}
+
+/* Helper function for or_comparisons_1:  try to simplify the OR of the
+   ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
+   If INVERT is true, invert the value of VAR before doing the OR.
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+or_var_with_comparison (tree var, bool invert,
+			enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t;
+  gimple stmt = SSA_NAME_DEF_STMT (var);
+
+  /* We can only deal with variables whose definitions are assignments.  */
+  if (!is_gimple_assign (stmt))
+    return NULL_TREE;
+  
+  /* If we have an inverted comparison, apply DeMorgan's law and rewrite
+     !var OR (op2a code2 op2b) => !(var AND !(op2a code2 op2b))
+     Then we only have to consider the simpler non-inverted cases.  */
+  if (invert)
+    t = and_var_with_comparison_1 (stmt, 
+				   invert_tree_comparison (code2, false),
+				   op2a, op2b);
+  else
+    t = or_var_with_comparison_1 (stmt, code2, op2a, op2b);
+  return canonicalize_bool (t, invert);
+}
+
+/* Try to simplify the OR of the ssa variable defined by the assignment
+   STMT with the comparison specified by (OP2A CODE2 OP2B).
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+or_var_with_comparison_1 (gimple stmt,
+			  enum tree_code code2, tree op2a, tree op2b)
+{
+  tree var = gimple_assign_lhs (stmt);
+  tree true_test_var = NULL_TREE;
+  tree false_test_var = NULL_TREE;
+  enum tree_code innercode = gimple_assign_rhs_code (stmt);
+
+  /* Check for identities like (var OR (var != 0)) => true .  */
+  if (TREE_CODE (op2a) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
+    {
+      if ((code2 == NE_EXPR && integer_zerop (op2b))
+	  || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
+	{
+	  true_test_var = op2a;
+	  if (var == true_test_var)
+	    return var;
+	}
+      else if ((code2 == EQ_EXPR && integer_zerop (op2b))
+	       || (code2 == NE_EXPR && integer_nonzerop (op2b)))
+	{
+	  false_test_var = op2a;
+	  if (var == false_test_var)
+	    return boolean_true_node;
+	}
+    }
+
+  /* If the definition is a comparison, recurse on it.  */
+  if (TREE_CODE_CLASS (innercode) == tcc_comparison)
+    {
+      tree t = or_comparisons_1 (innercode,
+				 gimple_assign_rhs1 (stmt),
+				 gimple_assign_rhs2 (stmt),
+				 code2,
+				 op2a,
+				 op2b);
+      if (t)
+	return t;
+    }
+  
+  /* If the definition is an AND or OR expression, we may be able to
+     simplify by reassociating.  */
+  if (innercode == TRUTH_AND_EXPR
+      || innercode == TRUTH_OR_EXPR
+      || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
+	  && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
+    {
+      tree inner1 = gimple_assign_rhs1 (stmt);
+      tree inner2 = gimple_assign_rhs2 (stmt);
+      gimple s;
+      tree t;
+      tree partial = NULL_TREE;
+      bool is_or = (innercode == TRUTH_OR_EXPR || innercode == BIT_IOR_EXPR);
+      
+      /* Check for boolean identities that don't require recursive examination
+	 of inner1/inner2:
+	 inner1 OR (inner1 OR inner2) => inner1 OR inner2 => var
+	 inner1 OR (inner1 AND inner2) => inner1
+	 !inner1 OR (inner1 OR inner2) => true
+	 !inner1 OR (inner1 AND inner2) => !inner1 OR inner2
+      */
+      if (inner1 == true_test_var)
+	return (is_or ? var : inner1);
+      else if (inner2 == true_test_var)
+	return (is_or ? var : inner2);
+      else if (inner1 == false_test_var)
+	return (is_or
+		? boolean_true_node
+		: or_var_with_comparison (inner2, false, code2, op2a, op2b));
+      else if (inner2 == false_test_var)
+	return (is_or
+		? boolean_true_node
+		: or_var_with_comparison (inner1, false, code2, op2a, op2b));
+      
+      /* Next, redistribute/reassociate the OR across the inner tests.
+	 Compute the first partial result, (inner1 OR (op2a code op2b))  */
+      if (TREE_CODE (inner1) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
+					     gimple_assign_rhs1 (s),
+					     gimple_assign_rhs2 (s),
+					     code2, op2a, op2b)))
+	{
+	  /* Handle the OR case, where we are reassociating:
+	     (inner1 OR inner2) OR (op2a code2 op2b)
+	     => (t OR inner2)
+	     If the partial result t is a constant, we win.  Otherwise
+	     continue on to try reassociating with the other inner test.  */
+	  if (innercode == TRUTH_OR_EXPR)
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else if (integer_zerop (t))
+		return inner2;
+	    }
+	  
+	  /* Handle the AND case, where we are redistributing:
+	     (inner1 AND inner2) OR (op2a code2 op2b)
+	     => (t AND (inner2 OR (op2a code op2b)))  */
+	  else
+	    {
+	      if (integer_zerop (t))
+		return boolean_false_node;
+	      else
+		/* Save partial result for later.  */
+		partial = t;
+	    }
+	}
+      
+      /* Compute the second partial result, (inner2 OR (op2a code op2b)) */
+      if (TREE_CODE (inner2) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
+					     gimple_assign_rhs1 (s),
+					     gimple_assign_rhs2 (s),
+					     code2, op2a, op2b)))
+	{
+	  /* Handle the OR case, where we are reassociating:
+	     (inner1 OR inner2) OR (op2a code2 op2b)
+	     => (inner1 OR t)  */
+	  if (innercode == TRUTH_OR_EXPR)
+	    {
+	      if (integer_zerop (t))
+		return inner1;
+	      else if (integer_onep (t))
+		return boolean_true_node;
+	    }
+	  
+	  /* Handle the AND case, where we are redistributing:
+	     (inner1 AND inner2) OR (op2a code2 op2b)
+	     => (t AND (inner1 OR (op2a code2 op2b)))
+	     => (t AND partial)  */
+	  else 
+	    {
+	      if (integer_zerop (t))
+		return boolean_false_node;
+	      else if (partial)
+		{
+		  /* We already got a simplification for the other
+		     operand to the redistributed AND expression.  The
+		     interesting case is when at least one is true.
+		     Or, if both are the same, we can apply the identity
+		     (x AND x) == true.  */
+		  if (integer_onep (partial))
+		    return t;
+		  else if (integer_onep (t))
+		    return partial;
+		  else if (same_bool_result_p (t, partial))
+		    return boolean_true_node;
+		}
+	    }
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the OR of two comparisons defined by
+   (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
+   If this can be done without constructing an intermediate value,
+   return the resulting tree; otherwise NULL_TREE is returned.
+   This function is deliberately asymmetric as it recurses on SSA_DEFs
+   in the first comparison but not the second.  */
+
+static tree
+or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		  enum tree_code code2, tree op2a, tree op2b)
+{
+  /* First check for ((x CODE1 y) OR (x CODE2 y)).  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && operand_equal_p (op1b, op2b, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ORIF_EXPR, code1, code2,
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* Likewise the swapped case of the above.  */
+  if (operand_equal_p (op1a, op2b, 0)
+      && operand_equal_p (op1b, op2a, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ORIF_EXPR, code1,
+				    swap_tree_comparison (code2),
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* If both comparisons are of the same value against constants, we might
+     be able to merge them.  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && TREE_CODE (op1b) == INTEGER_CST
+      && TREE_CODE (op2b) == INTEGER_CST)
+    {
+      int cmp = tree_int_cst_compare (op1b, op2b);
+
+      /* If we have (op1a != op1b), we should either be able to
+	 return that or TRUE, depending on whether the constant op1b
+	 also satisfies the other comparison against op2b.  */
+      if (code1 == NE_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return boolean_true_node;
+	      else
+		return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	    }
+	}
+      /* Likewise if the second comparison is a != comparison.  */
+      else if (code2 == NE_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return boolean_true_node;
+	      else
+		return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	    }
+	}
+
+      /* See if an equality test is redundant with the other comparison.  */
+      else if (code1 == EQ_EXPR)
+	{
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+      else if (code2 == EQ_EXPR)
+	{
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Chose the less restrictive of two < or <= comparisons.  */
+      else if ((code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	{
+	  if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	  else
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Likewise chose the less restrictive of two > or >= comparisons.  */
+      else if ((code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	{
+	  if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	  else
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Check for singleton ranges.  */
+      else if (cmp == 0
+	       && ((code1 == LT_EXPR && code2 == GT_EXPR)
+		   || (code1 == GT_EXPR && code2 == LT_EXPR)))
+	return fold_build2 (NE_EXPR, boolean_type_node, op1a, op2b);
+
+      /* Check for less/greater pairs that don't restrict the range at all.  */
+      else if (cmp >= 0
+	       && (code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	return boolean_true_node;
+      else if (cmp <= 0
+	       && (code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	return boolean_true_node;
+    }
+
+  /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
+     NAME's definition is a truth value.  See if there are any simplifications
+     that can be done against the NAME's definition.  */
+  if (TREE_CODE (op1a) == SSA_NAME
+      && (code1 == NE_EXPR || code1 == EQ_EXPR)
+      && (integer_zerop (op1b) || integer_onep (op1b)))
+    {
+      bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
+		     || (code1 == NE_EXPR && integer_onep (op1b)));
+      gimple stmt = SSA_NAME_DEF_STMT (op1a);
+      switch (gimple_code (stmt))
+	{
+	case GIMPLE_ASSIGN:
+	  /* Try to simplify by copy-propagating the definition.  */
+	  return or_var_with_comparison (op1a, invert, code2, op2a, op2b);
+
+	case GIMPLE_PHI:
+	  /* If every argument to the PHI produces the same result when
+	     ORed with the second comparison, we win.
+	     Do not do this unless the type is bool since we need a bool
+	     result here anyway.  */
+	  if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
+	    {
+	      tree result = NULL_TREE;
+	      unsigned i;
+	      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+		{
+		  tree arg = gimple_phi_arg_def (stmt, i);
+		  
+		  /* If this PHI has itself as an argument, ignore it.
+		     If all the other args produce the same result,
+		     we're still OK.  */
+		  if (arg == gimple_phi_result (stmt))
+		    continue;
+		  else if (TREE_CODE (arg) == INTEGER_CST)
+		    {
+		      if (invert ? integer_zerop (arg) : integer_nonzerop (arg))
+			{
+			  if (!result)
+			    result = boolean_true_node;
+			  else if (!integer_onep (result))
+			    return NULL_TREE;
+			}
+		      else if (!result)
+			result = fold_build2 (code2, boolean_type_node,
+					      op2a, op2b);
+		      else if (!same_bool_comparison_p (result,
+							code2, op2a, op2b))
+			return NULL_TREE;
+		    }
+		  else if (TREE_CODE (arg) == SSA_NAME)
+		    {
+		      tree temp = or_var_with_comparison (arg, invert,
+							  code2, op2a, op2b);
+		      if (!temp)
+			return NULL_TREE;
+		      else if (!result)
+			result = temp;
+		      else if (!same_bool_result_p (result, temp))
+			return NULL_TREE;
+		    }
+		  else
+		    return NULL_TREE;
+		}
+	      return result;
+	    }
+
+	default:
+	  break;
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the OR of two comparisons, specified by
+   (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
+   If this can be simplified to a single expression (without requiring
+   introducing more SSA variables to hold intermediate values),
+   return the resulting tree.  Otherwise return NULL_TREE.
+   If the result expression is non-null, it has boolean type.  */
+
+tree
+maybe_fold_or_comparisons (enum tree_code code1, tree op1a, tree op1b,
+			   enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t = or_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
+  if (t)
+    return t;
+  else
+    return or_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
+}
+
 /* Try to optimize out __builtin_stack_restore.  Optimize it out
    if there is another __builtin_stack_restore in the same basic
    block and no calls or ASM_EXPRs are in between, or if this block's

=== modified file 'gcc/tree-ssa-ifcombine.c'
--- old/gcc/tree-ssa-ifcombine.c	2009-11-25 10:55:54 +0000
+++ new/gcc/tree-ssa-ifcombine.c	2010-07-30 13:21:51 +0000
@@ -366,21 +366,16 @@
 
   /* See if we have two comparisons that we can merge into one.  */
   else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison
-	   && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison
-	   && operand_equal_p (gimple_cond_lhs (inner_cond),
-			       gimple_cond_lhs (outer_cond), 0)
-	   && operand_equal_p (gimple_cond_rhs (inner_cond),
-			       gimple_cond_rhs (outer_cond), 0))
+	   && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison)
     {
-      enum tree_code code1 = gimple_cond_code (inner_cond);
-      enum tree_code code2 = gimple_cond_code (outer_cond);
       tree t;
 
-      if (!(t = combine_comparisons (UNKNOWN_LOCATION,
-	      			     TRUTH_ANDIF_EXPR, code1, code2,
-				     boolean_type_node,
-				     gimple_cond_lhs (outer_cond),
-				     gimple_cond_rhs (outer_cond))))
+      if (!(t = maybe_fold_and_comparisons (gimple_cond_code (inner_cond),
+					    gimple_cond_lhs (inner_cond),
+					    gimple_cond_rhs (inner_cond),
+					    gimple_cond_code (outer_cond),
+					    gimple_cond_lhs (outer_cond),
+					    gimple_cond_rhs (outer_cond))))
 	return false;
       t = canonicalize_cond_expr_cond (t);
       if (!t)
@@ -518,22 +513,17 @@
   /* See if we have two comparisons that we can merge into one.
      This happens for C++ operator overloading where for example
      GE_EXPR is implemented as GT_EXPR || EQ_EXPR.  */
-  else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison
-	   && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison
-	   && operand_equal_p (gimple_cond_lhs (inner_cond),
-			       gimple_cond_lhs (outer_cond), 0)
-	   && operand_equal_p (gimple_cond_rhs (inner_cond),
-			       gimple_cond_rhs (outer_cond), 0))
+    else if (TREE_CODE_CLASS (gimple_cond_code (inner_cond)) == tcc_comparison
+	   && TREE_CODE_CLASS (gimple_cond_code (outer_cond)) == tcc_comparison)
     {
-      enum tree_code code1 = gimple_cond_code (inner_cond);
-      enum tree_code code2 = gimple_cond_code (outer_cond);
       tree t;
 
-      if (!(t = combine_comparisons (UNKNOWN_LOCATION,
-	      			     TRUTH_ORIF_EXPR, code1, code2,
-				     boolean_type_node,
-				     gimple_cond_lhs (outer_cond),
-				     gimple_cond_rhs (outer_cond))))
+      if (!(t = maybe_fold_or_comparisons (gimple_cond_code (inner_cond),
+					   gimple_cond_lhs (inner_cond),
+					   gimple_cond_rhs (inner_cond),
+					   gimple_cond_code (outer_cond),
+					   gimple_cond_lhs (outer_cond),
+					   gimple_cond_rhs (outer_cond))))
 	return false;
       t = canonicalize_cond_expr_cond (t);
       if (!t)

=== modified file 'gcc/tree-ssa-reassoc.c'
--- old/gcc/tree-ssa-reassoc.c	2010-01-13 15:04:38 +0000
+++ new/gcc/tree-ssa-reassoc.c	2010-07-30 13:21:51 +0000
@@ -1159,6 +1159,117 @@
   return changed;
 }
 
+/* If OPCODE is BIT_IOR_EXPR or BIT_AND_EXPR and CURR is a comparison
+   expression, examine the other OPS to see if any of them are comparisons
+   of the same values, which we may be able to combine or eliminate.
+   For example, we can rewrite (a < b) | (a == b) as (a <= b).  */
+
+static bool
+eliminate_redundant_comparison (enum tree_code opcode,
+				VEC (operand_entry_t, heap) **ops,
+				unsigned int currindex,
+				operand_entry_t curr)
+{
+  tree op1, op2;
+  enum tree_code lcode, rcode;
+  gimple def1, def2;
+  int i;
+  operand_entry_t oe;
+
+  if (opcode != BIT_IOR_EXPR && opcode != BIT_AND_EXPR)
+    return false;
+
+  /* Check that CURR is a comparison.  */
+  if (TREE_CODE (curr->op) != SSA_NAME)
+    return false;
+  def1 = SSA_NAME_DEF_STMT (curr->op);
+  if (!is_gimple_assign (def1))
+    return false;
+  lcode = gimple_assign_rhs_code (def1);
+  if (TREE_CODE_CLASS (lcode) != tcc_comparison)
+    return false;
+  op1 = gimple_assign_rhs1 (def1);
+  op2 = gimple_assign_rhs2 (def1);
+
+  /* Now look for a similar comparison in the remaining OPS.  */
+  for (i = currindex + 1;
+       VEC_iterate (operand_entry_t, *ops, i, oe);
+       i++)
+    {
+      tree t;
+
+      if (TREE_CODE (oe->op) != SSA_NAME)
+	continue;
+      def2 = SSA_NAME_DEF_STMT (oe->op);
+      if (!is_gimple_assign (def2))
+	continue;
+      rcode = gimple_assign_rhs_code (def2);
+      if (TREE_CODE_CLASS (rcode) != tcc_comparison)
+	continue;
+
+      /* If we got here, we have a match.  See if we can combine the
+	 two comparisons.  */
+      if (opcode == BIT_IOR_EXPR)
+	t = maybe_fold_or_comparisons (lcode, op1, op2,
+				       rcode, gimple_assign_rhs1 (def2),
+				       gimple_assign_rhs2 (def2));
+      else
+	t = maybe_fold_and_comparisons (lcode, op1, op2,
+					rcode, gimple_assign_rhs1 (def2),
+					gimple_assign_rhs2 (def2));
+      if (!t)
+	continue;
+
+      /* maybe_fold_and_comparisons and maybe_fold_or_comparisons
+	 always give us a boolean_type_node value back.  If the original
+	 BIT_AND_EXPR or BIT_IOR_EXPR was of a wider integer type,
+	 we need to convert.  */
+      if (!useless_type_conversion_p (TREE_TYPE (curr->op), TREE_TYPE (t)))
+	t = fold_convert (TREE_TYPE (curr->op), t);
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Equivalence: ");
+	  print_generic_expr (dump_file, curr->op, 0);
+	  fprintf (dump_file, " %s ", op_symbol_code (opcode));
+	  print_generic_expr (dump_file, oe->op, 0);
+	  fprintf (dump_file, " -> ");
+	  print_generic_expr (dump_file, t, 0);
+	  fprintf (dump_file, "\n");
+	}
+
+      /* Now we can delete oe, as it has been subsumed by the new combined
+         expression t.  */
+      VEC_ordered_remove (operand_entry_t, *ops, i);
+      reassociate_stats.ops_eliminated ++;
+
+      /* If t is the same as curr->op, we're done.  Otherwise we must
+	 replace curr->op with t.  Special case is if we got a constant
+	 back, in which case we add it to the end instead of in place of
+	 the current entry.  */
+      if (TREE_CODE (t) == INTEGER_CST)
+	{
+	  VEC_ordered_remove (operand_entry_t, *ops, currindex);
+	  add_to_ops_vec (ops, t);
+	}
+      else if (!operand_equal_p (t, curr->op, 0))
+	{
+	  tree tmpvar;
+	  gimple sum;
+	  enum tree_code subcode;
+	  tree newop1;
+	  tree newop2;
+	  tmpvar = create_tmp_var (TREE_TYPE (t), NULL);
+	  add_referenced_var (tmpvar);
+	  extract_ops_from_tree (t, &subcode, &newop1, &newop2);
+	  sum = build_and_add_sum (tmpvar, newop1, newop2, subcode);
+	  curr->op = gimple_get_lhs (sum);
+	}
+      return true;
+    }
+
+  return false;
+}
 
 /* Perform various identities and other optimizations on the list of
    operand entries, stored in OPS.  The tree code for the binary
@@ -1220,7 +1331,8 @@
       if (eliminate_not_pairs (opcode, ops, i, oe))
 	return;
       if (eliminate_duplicate_pair (opcode, ops, &done, i, oe, oelast)
-	  || (!done && eliminate_plus_minus_pair (opcode, ops, i, oe)))
+	  || (!done && eliminate_plus_minus_pair (opcode, ops, i, oe))
+	  || (!done && eliminate_redundant_comparison (opcode, ops, i, oe)))
 	{
 	  if (done)
 	    return;