[patch, libgfortran] PR32611 Print sign of negative zero

[Steve Kargl]

On Mon, Jul 09, 2007 at 07:57:44PM -0700, Jerry DeLisle wrote:
> Brooks Moses wrote:
> >Jerry DeLisle wrote:
> >>The attached patch provides a solution to this PR.
> >>
> >>The patch uses the signbit function to determine if a zero value is 
> >>negative. If so, the sign is emitted.  If -std=legacy is specified at 
> >>compile time, the negative sign for zero values is not emitted.
> >>
> >>This patch requires -std=legacy to be used to pass NIST.  This is 
> >>because F77 explicitly prohibits printing the negative sign for zero 
> >>values.
> >[...]
> >>OK for trunk?
> >
> >This needs documenting, of course.
> >
> >If you aren't sure of the best place to document it, feel free to create 
> >a documentation PR about it and assign it to me, and I'll get to it 
> >sometime in August when I have time to think again.  :)
> >
> >In particular, note that this changes the meaning of the -std= option.
> >Currently, it only affects what language features are accepted, 
> >rejected, or warned about, but any program that compiles will have the 
> >same behavior regardless of which -std= option was used to compile it.
> >Your patch changes this, which is IMHO a fairly significant little change.
> >
> Do you think it better to have a separate compiler option like -fsign-zero?
> 
> Others please chime in.

I'd rather see -std=f77.  For -std=gnu, which is the default behavior,
gfortran should output the minus.

-- 
Steve