On Fri, 21 Jan 2022 09:55:01 -0700
Jerry James <loganjerry(a)gmail.com> wrote:
On Fri, Jan 14, 2022 at 7:32 AM Jakub Jelinek
<jakub(a)redhat.com> wrote:
> Another important thing I wanted to say is that we'd like to switch
> ppc64le from the numerically problematic IBM extended long double to
> IEEE 754 quad long double. This is an ABI change. Some libraries
> are already built so that they support both ABIs at the same time,
> including glibc, libstdc++, libgcc, libgfortran etc.
> For other libraries and binaries, the compiler, assembler and linker
> will notice if they use long double and flag them as using either
> IBM or IEEE long double and linker (or I think dynamic linker too)
> might complain when things are mixed.
> Right now the rawhide gcc still defaults to -mabi=ibmlongdouble
> but the glibc/gcc libraries are built compatibly with both.
> We'd like to configure gcc shortly before the mass rebuild with
> --with-long-double-format=ieee so that it will default to
> -mabi=ieeelongdouble, probably on a side-tag build first, and it
> will be highly desirable to rebuild at least some of the most commonly
> used library packages in the order of dependencies there, otherwise
> I'd be afraid the mass rebuild could fail for way too many packages
> (as the mass rebuild doesn't do dependency order rebuilds but just
> goes through packages alphabetically or so).
I don't know if this change is involved, but I've got several packages
that failed to build on ppc64le only, with what look like gcc
segfaults:
- cli11:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81476792
- dra2ter:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81482527
- libfplll:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81533813
- libpoly:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81536797
- mp:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81548297
- python-fpylll:
https://koji.fedoraproject.org/koji/taskinfo?taskID=81597035
>
> Since gcc uses libmpc, it's probably important to look at that one carefully.
> --
> Jerry James
>