diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index dbdc9c2..da9579e 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8662,6 +8662,26 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) if (integer_zerop (arg1)) return non_lvalue (fold_convert (type, arg0)); + /* ~X + X is -1. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) + && !TYPE_TRAP_SIGNED (type)) + { + t1 = build_int_cst (type, -1); + t1 = force_fit_type (t1, 0, false, false); + return omit_one_operand (type, t1, arg1); + } + + /* X + ~X is -1. */ + if (TREE_CODE (arg1) == BIT_NOT_EXPR + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0) + && !TYPE_TRAP_SIGNED (type)) + { + t1 = build_int_cst (type, -1); + t1 = force_fit_type (t1, 0, false, false); + return omit_one_operand (type, t1, arg0); + } + /* If we are adding two BIT_AND_EXPR's, both of which are and'ing with a constant, and the two constants have no bits in common, we should treat this as a BIT_IOR_EXPR since this may produce more @@ -9002,7 +9022,8 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) /* Convert -A - 1 to ~A. */ if (INTEGRAL_TYPE_P (type) && TREE_CODE (arg0) == NEGATE_EXPR - && integer_onep (arg1)) + && integer_onep (arg1) + && !TYPE_TRAP_SIGNED (type)) return fold_build1 (BIT_NOT_EXPR, type, fold_convert (type, TREE_OPERAND (arg0, 0))); |