[Bug c++/60237] isnan fails with -ffast-math

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60237

--- Comment #7 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to N Schaeffer from comment #6)
> Is there somewhere a rationale for not making isnan() find NaN's with
> -ffinite-math-only ?

finite-math-only is basically a promise that isinf and isnan always return
false...

I have inline library functions that do: if (isnan(x)) ...
When compiled with -ffinite-math-only, I want this eliminated as dead code,
that's the reason I made the function inline in the first place.

Another way to cheat:
int myisnan(double)__asm__("isnan");