Re: isfinite() failure on Cygwin with gcc 3.4.1

[Jeff Johnston <jjohnstn at redhat dot com>]

A fix has been checked in to avoid using the same input variable names for these 
macros which nest.

-- Jeff J.

William M. (Mike) Miller wrote:
> Andrew Pinski wrote:
>
> > Lets look at the definition of the macros again:
> >
> >
> > > #define fpclassify(x) \
> > >          (__extension__ ({__typeof__(x) __x = (x); \
> > >                           (sizeof (__x) == sizeof (float))  ? 
> > > __fpclassifyf(__x) : __fpclassifyd(__x);}))
> > >
> > > #define isfinite(x) \
> > >          (__extension__ ({__typeof__(x) __x = (x); \
> > >                           fpclassify(__x) != FP_INFINITE && 
> > > fpclassify(__x) != FP_NAN;}))
> >
> >
> >
> > See how we pass __x to fpclassify, well when we preprocessed the 
> > source we get in there:
> > __typeof__(x) __x = (__x); which just makes this uninitialized.  The 
> > reason why we
> > don't warn about it in gcc is because int a = a; is documented to have 
> > the uninitilizated
> > warnings to go away.
> >
> > Thanks,
> > Andrew Pinski
> > a gcc developer and a gcc bug master
>
>
> Aha, mystery solved!  (*smacking forehead*) I should have noticed that 
> -- would have made for a shorter bug report.  Thanks for looking into it.