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author | Richard Guenther <rguenther@suse.de> | 2009-03-31 14:28:16 +0000 |
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committer | Richard Biener <rguenth@gcc.gnu.org> | 2009-03-31 14:28:16 +0000 |
commit | 6b12efe971ad59e925d119243e6b6fabfdc2ba05 (patch) | |
tree | 3375dd6b6a930ea767bbaf4394885cf7b47d7023 | |
parent | 108f6c2f4efe0141c859eeb52fae610b8806ffc8 (diff) | |
download | gcc-6b12efe971ad59e925d119243e6b6fabfdc2ba05.zip gcc-6b12efe971ad59e925d119243e6b6fabfdc2ba05.tar.gz gcc-6b12efe971ad59e925d119243e6b6fabfdc2ba05.tar.bz2 |
re PR middle-end/31029 (Fold does not fold C - a == a)
2009-03-31 Richard Guenther <rguenther@suse.de>
PR middle-end/31029
* fold-const.c (fold_binary): Fold X +- Y CMP X to Y CMP 0 for
equality comparisons. Fold C - X CMP X if C % 2 == 1.
* gcc.dg/fold-compare-4.c: New testcase.
* gcc.dg/fold-compare-5.c: Likewise.
From-SVN: r145345
-rw-r--r-- | gcc/ChangeLog | 6 | ||||
-rw-r--r-- | gcc/fold-const.c | 33 | ||||
-rw-r--r-- | gcc/testsuite/ChangeLog | 6 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/fold-compare-4.c | 23 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/fold-compare-5.c | 20 |
5 files changed, 77 insertions, 11 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0f81767..e389951 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,11 @@ 2009-03-31 Richard Guenther <rguenther@suse.de> + PR middle-end/31029 + * fold-const.c (fold_binary): Fold X +- Y CMP X to Y CMP 0 for + equality comparisons. Fold C - X CMP X if C % 2 == 1. + +2009-03-31 Richard Guenther <rguenther@suse.de> + * tree.h (div_if_zero_remainder): Declare. * fold-const.c (div_if_zero_remainder): Export. * tree-ssa-forwprop.c diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 4951600..ec06954 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -12191,22 +12191,33 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) fold_convert (TREE_TYPE (arg0), arg1), TREE_OPERAND (arg0, 1))); - /* Transform comparisons of the form X +- C CMP X. */ - if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) + /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */ + if ((TREE_CODE (arg0) == PLUS_EXPR + || TREE_CODE (arg0) == POINTER_PLUS_EXPR + || TREE_CODE (arg0) == MINUS_EXPR) && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST && (INTEGRAL_TYPE_P (TREE_TYPE (arg0)) || POINTER_TYPE_P (TREE_TYPE (arg0)))) { - tree cst = TREE_OPERAND (arg0, 1); + tree val = TREE_OPERAND (arg0, 1); + return omit_two_operands (type, + fold_build2 (code, type, + val, + build_int_cst (TREE_TYPE (val), + 0)), + TREE_OPERAND (arg0, 0), arg1); + } - if (code == EQ_EXPR - && !integer_zerop (cst)) - return omit_two_operands (type, boolean_false_node, - TREE_OPERAND (arg0, 0), arg1); - else - return omit_two_operands (type, boolean_true_node, - TREE_OPERAND (arg0, 0), arg1); + /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */ + if (TREE_CODE (arg0) == MINUS_EXPR + && TREE_CODE (TREE_OPERAND (arg0, 0)) == INTEGER_CST + && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0) + && (TREE_INT_CST_LOW (TREE_OPERAND (arg0, 0)) & 1) == 1) + { + return omit_two_operands (type, + code == NE_EXPR + ? boolean_true_node : boolean_false_node, + TREE_OPERAND (arg0, 1), arg1); } /* If we have X - Y == 0, we can convert that to X == Y and similarly diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9b1aef3..19cf3d6 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,11 @@ 2009-03-31 Richard Guenther <rguenther@suse.de> + PR middle-end/31029 + * gcc.dg/fold-compare-4.c: New testcase. + * gcc.dg/fold-compare-5.c: Likewise. + +2009-03-31 Richard Guenther <rguenther@suse.de> + * gcc.dg/tree-ssa/forwprop-12.c: New testcase. 2009-03-31 Joseph Myers <joseph@codesourcery.com> diff --git a/gcc/testsuite/gcc.dg/fold-compare-4.c b/gcc/testsuite/gcc.dg/fold-compare-4.c new file mode 100644 index 0000000..d4bb64a --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-compare-4.c @@ -0,0 +1,23 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-original" } */ + +int test1 (int a, int b) +{ + return a - b == a; +} +int test2 (int a, int b) +{ + return a + b == a; +} +int test3 (int a) +{ + return a + 5 == a; +} +int test4 (int a) +{ + return a - 5 == a; +} + +/* { dg-final { scan-tree-dump-times "b == 0" 2 "original" } } */ +/* { dg-final { scan-tree-dump-times "return 0" 2 "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */ diff --git a/gcc/testsuite/gcc.dg/fold-compare-5.c b/gcc/testsuite/gcc.dg/fold-compare-5.c new file mode 100644 index 0000000..9ec8c33 --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-compare-5.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-original" } */ + +int test1 (int a) +{ + return 2 - a == a; +} +int test2 (int a) +{ + return 1 - a == a; +} +int test3 (int a) +{ + return 1 - a != a; +} + +/* { dg-final { scan-tree-dump-times "return 2 - a == a" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "return 0" 1 "original" } } */ +/* { dg-final { scan-tree-dump-times "return 1" 1 "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */ |