[Bug fortran/95640] gfortran ieee_selected_real_kind returns 10

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95640

--- Comment #10 from kargl at gcc dot gnu.org ---
(In reply to Steve Kargl from comment #9)
> On Thu, Jun 11, 2020 at 10:14:21AM -0700, Steve Kargl wrote:
> > 
> > IEEE-754 calls binary32, 64, 128 the basic formats (Sec. 3, p. 6):
> > 
> >   Five basic formats are defined in this clause:
> >     Three binary formats, with encodings in lengths of 32, 64, and 128 bits.
> >     Two decimal formats, with encodings in lengths of 64 and 128 bits.
> > 
> >   Additional arithmetic formats are recommended for extending these basic
> >   formats (see 3.7).
> > 
> > If J3 really intended that IEEE_SELECTED_REAL_KIND return a kind for one of
> > IEEE-754 basic formats, then it ought to say that.   Looks like a defect
> > in the Fortran standard.
> > 
> > If one looks into 3.7 (p. 14), it further recommends
> > 
> >   Language standards should define mechanisms supporting extendable
> >   precision for each supported radix.
> > 
> 
> I have asked on the J3 mailing list if Section 17 should
> be restricted to the basic formats.

https://mailman.j3-fortran.org/pipermail/j3/2020-June/012148.html

Bill, is Malcolm's feedback sufficient?

This may fall under some processors may not support
the Intel-80 floating point format under Section 17
of the Standard.

I'll leave the bug report open for others to chime in.
Perhaps, others would rather not have a difference 
between gfortran and Cray and Intel compilers.