Re: [PATCH] fortran, libgfortran, v3: Avoid using libquadmath for glibc 2.26+

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Jun 28, 2022 at 10:35:03AM +0200, Tobias Burnus wrote:
> On 27.06.22 15:30, Jakub Jelinek via Gcc-patches wrote:
> 
> > Ok, here is an updated patch that uses _Float128/_Complex _Float128 for all
> > of GFC_REAL_{16,17}_IS_FLOAT128, but still uses q/Q suffixes on literal
> > constants etc. when using libquadmath and f128/F128 otherwise.
> > This patch also includes the incremental powerpc64le fixes.
> > 
> > Ok if it passes testing?
> 
> LGTM – I am not completely happy of having a TARGET_GLIBC_M{AJ,IN}OR check
> in the FE

I've used it because it is already (though my fault too) used for the
powerpc64le stuff in the FE too.
The alternative would be grepping of target glibc headers in
gcc/configure.ac, because I think we can't during gcc configure time
preprocess the target glibc header (at least not reliably) because
at that point we just have host compiler which might be a different
architecture.  So, we could e.g. grep for
grep '^[[:blank:]]*#[[:blank:]]*define[[:blank:]]*__HAVE_FLOAT128[[:blank:]]*1' $target_header_dir/bits/floatn.h
or so.
Currently all arches that do have the IEC 60559 _Float128 *f128 APIs
in glibc were added in glibc 2.26, if some extra are added later
or some other libraries add those, we can always improve the checks.

	Jakub