Re: [r14-159 Regression] FAIL: std/ranges/iota/max_size_type.cc execution test on Linux/x86_64

[Jonathan Wakely <jwakely@redhat.com>]

On Mon, 24 Apr 2023 at 17:27, Patrick Palka <ppalka@redhat.com> wrote:
>
> On Sun, 23 Apr 2023, Jonathan Wakely wrote:
>
> >
> >
> > On Saturday, April 22, 2023, Jakub Jelinek <jakub@redhat.com> wrote:
> > > On Sat, Apr 22, 2023 at 11:30:24AM +0800, haochen.jiang via Gcc-patches wrote:
> > >> On Linux/x86_64,
> > >>
> > >> 03cebd304955a6b9c5607e09312d77f1307cc98e is the first bad commit
> > >> commit 03cebd304955a6b9c5607e09312d77f1307cc98e
> > >> Author: Jason Merrill <jason@redhat.com>
> > >> Date:   Tue Apr 18 21:32:07 2023 -0400
> > >>
> > >>     c++: fix 'unsigned typedef-name' extension [PR108099]
> > >>
> > >> caused
> > >>
> > >> FAIL: std/ranges/iota/max_size_type.cc execution test
> > >
> > > That is mentioned in
> > > https://gcc.gnu.org/pipermail/gcc-patches/2023-April/616439.html
> > > as known problem.  I think the test should use std::make_signed<rep_t>
> > > instead of signed rep_t
>
> IIUC we can't portably use make_signed here since __int128 is considered
> an integral type only in GNU mode and not in strict mode.

Right (for now ... C++23 means we can make it an integer type, and I
think we might as well apply that to all -std modes, but that work
isn't done yet).

>
> >
> > It's already testing non-public implementation details, it could just use #if and use signed __int128 or signed long long as appropriate.
>
> Sounds good, patch posted at https://gcc.gnu.org/pipermail/gcc-patches/2023-April/616598.html