[PATCH][GCC][PATCHv3] Improve fpclassify w.r.t IEEE like numbers in GIMPLE.

[Joseph Myers]

On Thu, 8 Jun 2017, Richard Biener wrote:

> For a built-in this is generally valid.  For plain isnan it depends on 
> what the standard says.
> 
> You have to support taking the address of isnan anyway and thus 
> expanding to a library call in that case.  Why doesn't that not work?

In the case of isnan there is the Unix98 non-type-generic function, so it 
should definitely work to take the address of that function as declared in 
the system headers.

For the DEF_GCC_BUILTIN type-generic functions there may not be any 
corresponding library function at all (as well as only being callable with 
the __builtin_* name).

-- 
Joseph S. Myers
joseph@codesourcery.com