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| author | Roger Sayle <roger@eyesopen.com> | 2006-11-12 18:41:31 +0000 |
|---|---|---|
| committer | Roger Sayle <sayle@gcc.gnu.org> | 2006-11-12 18:41:31 +0000 |
| commit | 015e23f4005b00afaf87c90ef67db48b364fe70e (patch) | |
| tree | b02ba3cb889c222125601c7fa415210e5d22fcf6 /gcc/fold-const.c | |
| parent | c0493b13fb859a27d5554c18ff11db2c1ebb7241 (diff) | |
| download | gcc-015e23f4005b00afaf87c90ef67db48b364fe70e.zip gcc-015e23f4005b00afaf87c90ef67db48b364fe70e.tar.gz gcc-015e23f4005b00afaf87c90ef67db48b364fe70e.tar.bz2 | |
re PR tree-optimization/13827 ((a & b) != (c & b) should be transformed to ((a^c) & b) !=0)
PR tree-optimization/13827
* fold-const.c (fold_binary) <EQ_EXPR, NE_EXPR>: Fold (X&C) op (Y&C)
as ((X^Y)&C) op 0.
* gcc.dg/fold-eqand-1.c: New test case.
From-SVN: r118727
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 08e74a2..cf1df69 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -10818,6 +10818,49 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0)); + /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */ + if (TREE_CODE (arg0) == BIT_AND_EXPR + && TREE_CODE (arg1) == BIT_AND_EXPR) + { + tree arg00 = TREE_OPERAND (arg0, 0); + tree arg01 = TREE_OPERAND (arg0, 1); + tree arg10 = TREE_OPERAND (arg1, 0); + tree arg11 = TREE_OPERAND (arg1, 1); + tree itype = TREE_TYPE (arg0); + + if (operand_equal_p (arg01, arg11, 0)) + return fold_build2 (code, type, + fold_build2 (BIT_AND_EXPR, itype, + fold_build2 (BIT_XOR_EXPR, itype, + arg00, arg10), + arg01), + build_int_cst (itype, 0)); + + if (operand_equal_p (arg01, arg10, 0)) + return fold_build2 (code, type, + fold_build2 (BIT_AND_EXPR, itype, + fold_build2 (BIT_XOR_EXPR, itype, + arg00, arg11), + arg01), + build_int_cst (itype, 0)); + + if (operand_equal_p (arg00, arg11, 0)) + return fold_build2 (code, type, + fold_build2 (BIT_AND_EXPR, itype, + fold_build2 (BIT_XOR_EXPR, itype, + arg01, arg10), + arg00), + build_int_cst (itype, 0)); + + if (operand_equal_p (arg00, arg10, 0)) + return fold_build2 (code, type, + fold_build2 (BIT_AND_EXPR, itype, + fold_build2 (BIT_XOR_EXPR, itype, + arg01, arg11), + arg00), + build_int_cst (itype, 0)); + } + return NULL_TREE; case LT_EXPR: |