diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 029f25c..dd26986 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3007,15 +3007,17 @@ fold (expr) /* Except with IEEE floating point, x-0 equals x. */ if (real_zerop (arg1)) return non_lvalue (convert (type, arg0)); - } - /* Fold &x - &x. This can happen from &x.foo - &x. - Note that can't be done for certain floats even in non-IEEE formats. - Also note that operand_equal_p is always false is an operand - is volatile. */ - if (operand_equal_p (arg0, arg1, - TREE_CODE (type) == REAL_TYPE)) - return convert (type, integer_zero_node); + /* Fold &x - &x. This can happen from &x.foo - &x. + This is unsafe for certain floats even in non-IEEE formats. + In IEEE, it is unsafe because it does wrong for NaNs. + Also note that operand_equal_p is always false is an operand + is volatile. */ + + if (operand_equal_p (arg0, arg1, + TREE_CODE (type) == REAL_TYPE)) + return convert (type, integer_zero_node); + } goto associate; case MULT_EXPR: |