[Bug c++/54130] Recognize builtins with bool return type

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54130

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> 2012-07-31 09:38:38 UTC ---
(In reply to comment #1)
> I think your non-matching prototype disables builtin recognition.

Yes.

> The C standard specifies isnan as returning int, so I think GCC is correct here.

Note the "component: C++" for this bug. The C++11 standard says it returns
bool. I believe we want gcc to recognize both prototypes.