https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104389
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Changing it to
double
foo (void)
{
double a = __builtin_huge_val ();
return a * 0.0;
}
shows ccp1 applies
/* Maybe fold x * 0 to 0. The expressions aren't the same
when x is NaN, since x * 0 is also NaN. Nor are they the
same in modes with signed zeros, since multiplying a
negative value by 0 gives -0, not +0. */
(simplify
(mult @0 real_zerop@1)
(if (!tree_expr_maybe_nan_p (@0)
&& !tree_expr_maybe_real_minus_zero_p (@0)
&& !tree_expr_maybe_real_minus_zero_p (@1))
@1))
So the question is why tree_expr_maybe_nan_p isn't true.
