Re: [Patch, Fortran] PR 82143: add a -fdefault-real-16 flag

[David Edelsohn <dje.gcc@gmail.com>]

On Tue, Sep 26, 2017 at 4:44 AM, Janus Weil <janus@gcc.gnu.org> wrote:
> 2017-09-25 23:23 GMT+02:00 Steve Kargl <sgk@troutmask.apl.washington.edu>:
>> On Mon, Sep 25, 2017 at 11:14:42PM +0200, Janus Weil wrote:
>>> 2017-09-25 17:07 GMT+02:00 David Edelsohn <dje.gcc@gmail.com>:
>>> > promotion_3.f90 and promotion_4.f90 are failing on at least PowerPC
>>> > and AArch64.  Are these new tests limited to x86 or some long double
>>> > assumptions?
>>>
>>> These tests require the availability of  a 10- or 16-byte-wide REAL
>>> type, respectively. I have to admit that I do not have a complete
>>> overview of which targets in GCC's wide portfolio provide such a type.
>>>
>>> It seems that REAL(16) is supported via libquadmath on 32-bit x86,
>>> x86-64 and Itanium at least. I'm not sure about REAL(10).
>>>
>>> Targets that do not support such a type probably need to be XFAILed.
>>>
>>
>> Janus, I think you can control with a dg option
>>
>> dg-require-effective-target fortran_large_real
>>
>> See, for example, gfortran.dg/random_3.f90
>
> Thanks for the pointer, Steve.
>
> However, it seems that "fortran_large_real" only requires some real
> type that is larger than 8 byte, but makes no assumptions on its
> actual size (10 or 16 byte). Therefore it's probably not very useful
> for promotion_{3,4}.
>
> But: I found that there's also a "fortran_real_16", which should be
> suitable for promotion_3. Can someone verify if the following fixes
> the problem on the failing targets:
>
> Index: promotion_3.f90
> ===================================================================
> --- promotion_3.f90    (revision 253134)
> +++ promotion_3.f90    (working copy)
> @@ -1,5 +1,6 @@
>  ! { dg-do run }
>  ! { dg-options "-fdefault-real-16" }
> +! { dg-require-effective-target fortran_real_16 }
>  !
>  ! PR 82143: add a -fdefault-real-16 flag
>  !
>
>
> If it does, I'll be happy to commit that. For promotion_4, we probably
> need to add an effective target "fortran_real_10" (which does not seem
> to exists yet).

Testing fortran_real_16 fixes promotion_3.f90 on AIX.  I expect that
the new dg test will work for promotion_4.f90.

Thanks, David