diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index e1a497eda96..e48aae9f4ce 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -10866,13 +10866,19 @@ fold_binary_loc (location_t loc, if (operand_equal_p (arg0, arg1, 0)) return non_lvalue_loc (loc, fold_convert_loc (loc, type, arg0)); - /* ~X & X is always zero. */ - if (TREE_CODE (arg0) == BIT_NOT_EXPR + /* ~X & X, (X == 0) & X, and !X & X are always zero. */ + if ((TREE_CODE (arg0) == BIT_NOT_EXPR + || TREE_CODE (arg0) == TRUTH_NOT_EXPR + || (TREE_CODE (arg0) == EQ_EXPR + && integer_zerop (TREE_OPERAND (arg0, 1)))) && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)) return omit_one_operand_loc (loc, type, integer_zero_node, arg1); - /* X & ~X is always zero. */ - if (TREE_CODE (arg1) == BIT_NOT_EXPR + /* X & ~X , X & (X == 0), and X & !X are always zero. */ + if ((TREE_CODE (arg1) == BIT_NOT_EXPR + || TREE_CODE (arg1) == TRUTH_NOT_EXPR + || (TREE_CODE (arg1) == EQ_EXPR + && integer_zerop (TREE_OPERAND (arg1, 1)))) && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0)) return omit_one_operand_loc (loc, type, integer_zero_node, arg0); @@ -10933,6 +10939,14 @@ fold_binary_loc (location_t loc, build_int_cst (TREE_TYPE (tem), 1)), build_int_cst (TREE_TYPE (tem), 0)); } + /* Fold !X & 1 as X == 0. */ + if (TREE_CODE (arg0) == TRUTH_NOT_EXPR + && integer_onep (arg1)) + { + tem = TREE_OPERAND (arg0, 0); + return fold_build2_loc (loc, EQ_EXPR, type, tem, + build_int_cst (TREE_TYPE (tem), 0)); + } /* Fold (X ^ Y) & Y as ~X & Y. */ if (TREE_CODE (arg0) == BIT_XOR_EXPR @@ -12357,14 +12371,6 @@ fold_binary_loc (location_t loc, } } - /* If this is an NE comparison of zero with an AND of one, remove the - comparison since the AND will give the correct value. */ - if (code == NE_EXPR - && integer_zerop (arg1) - && TREE_CODE (arg0) == BIT_AND_EXPR - && integer_onep (TREE_OPERAND (arg0, 1))) - return fold_convert_loc (loc, type, arg0); - /* If we have (A & C) == C where C is a power of 2, convert this into (A & C) != 0. Similarly for NE_EXPR. */ if (TREE_CODE (arg0) == BIT_AND_EXPR |