diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index beee337..3bc27eb 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8757,9 +8757,23 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) && ! lookup_attribute ("alias", DECL_ATTRIBUTES (TREE_OPERAND (arg1, 0))) && ! DECL_EXTERNAL (TREE_OPERAND (arg1, 0))) - return constant_boolean_node (operand_equal_p (arg0, arg1, 0) - ? code == EQ_EXPR : code != EQ_EXPR, - type); + { + /* We know that we're looking at the address of two + non-weak, unaliased, static _DECL nodes. + + It is both wasteful and incorrect to call operand_equal_p + to compare the two ADDR_EXPR nodes. It is wasteful in that + all we need to do is test pointer equality for the arguments + to the two ADDR_EXPR nodes. It is incorrect to use + operand_equal_p as that function is NOT equivalent to a + C equality test. It can in fact return false for two + objects which would test as equal using the C equality + operator. */ + bool equal = TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0); + return constant_boolean_node (equal + ? code == EQ_EXPR : code != EQ_EXPR, + type); + } /* If this is a comparison of two exprs that look like an ARRAY_REF of the same object, then we can fold this to a |