diff options
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: |