Re: [PATCH] Fortran: add Fortran 2018 IEEE_{MIN,MAX} functions

[Steve Kargl <sgk@troutmask.apl.washington.edu>]

On Wed, Jun 07, 2023 at 08:31:35PM +0200, Harald Anlauf via Fortran wrote:
> Hi FX,
> 
> On 6/6/23 21:11, FX Coudert via Gcc-patches wrote:
> > Hi,
> > 
> > > I cannot see if there is proper support for kind=17 in your patch;
> > > at least the libgfortran/ieee/ieee_arithmetic.F90 part does not
> > > seem to have any related code.
> > 
> > Can real(kind=17) ever be an IEEE mode? If so, something seriously wrong happened, because the IEEE modules have no kind=17 mention in them anywhere.
> > 
> > Actually, where is the kind=17 documented?
> > 
> > FX
> 
> I was hoping for Thomas to come forward with some comment, as
> he was quite involved in related work.
> 
> There are several threads on IEEE128 for Power on the fortran ML
> e.g. around November/December 2021, January 2022.
> 
> I wasn't meaning to block your work, just wondering if the Power
> platform needs more attention here.
> 

% cd gcc/gccx/libgfortran
% grep HAVE_GFC_REAL_17 ieee/*
% troutmask:sgk[219] ls ieee
% ieee_arithmetic.F90     ieee_features.F90
% ieee_exceptions.F90     ieee_helper.c

There are zero hits for REAL(17) in the IEEE code.  If REAL(17)
is intended to be an IEEE-754 type, then it seems gfortran's
support was never added for it.  If anyone has access to a
power system, it's easy to test

program foo
   use ieee_arithmetic
   print *, ieee_support_datatype(1.e_17)
end program foo
-- 
Steve