- if (INTEGRAL_TYPE_P (TREE_TYPE (t))
- && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t)))
- break;
- return negate_expr_p (TREE_OPERAND (t, 1))
- || negate_expr_p (TREE_OPERAND (t, 0));
+ if (INTEGRAL_TYPE_P (TREE_TYPE (t)))
+ {
+ if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t)))
+ break;
+ /* If overflow is undefined then we have to be careful because
+ we ask whether it's ok to associate the negate with the
+ division which is not ok for example for
+ -((a - b) / c) where (-(a - b)) / c may invoke undefined
+ overflow because of negating INT_MIN. So do not use
+ negate_expr_p here but open-code the two important cases. */
+ if (TREE_CODE (TREE_OPERAND (t, 0)) == NEGATE_EXPR
+ || (TREE_CODE (TREE_OPERAND (t, 0)) == INTEGER_CST
+ && may_negate_without_overflow_p (TREE_OPERAND (t, 0))))
+ return true;
+ }
+ else if (negate_expr_p (TREE_OPERAND (t, 0)))
+ return true;
+ return negate_expr_p (TREE_OPERAND (t, 1));