New Jacks Regressions: Constant Folding of Casts

Tue Jul 20 07:41:00 GMT 2004

On Jul 20, 2004, at 12:30 AM, Ranjit Mathew wrote:
> Hi,
>> In the last 24 hours, the following:
>> case ((int )Float.NaN == 0 ? 1 : 0): break;
>> now gives an error saying "Constant expression required".
> This causes 4 new Jacks failures. (Note that casting NaN
> to an int should give the value 0.)
>> I note that something like "0 == 0 ? 1 : 0" does not
> give this error.
>> I am not able to quickly tell what could be causing
> this failure.
>> Any insights?

Maybe this change has something to do with it:
2004年07月19日 Roger Sayle <roger@eyesopen.com>
 * fold-const.c (tree_expr_nonzero_p): Add function prototype.
 (fold) <EQ_EXPR>: Move tree_expr_nonzero_p optimization from
 fold_relational_const to here, i.e. "(x | 5) == 0" -> false.
 (fold) (UNEQ_EXPR>: Add optimizations for unordered comparisons
 of the form "x op x" where op is UNLE, UNGE, UNEQ or LTGT.
 (fold_relational_const): Tidy up handling of floating point
 comparisons by calling real_compare. Remove tree_expr_nonzero_p
 transformation; fold_relational_const assumes constant operands.
Since that is the only change fold not to fold something.
Thanks,
Andrew Pinski