[PATCH v3 5/7] x86: Optimize strcmp-avx2.S

[Noah Goldstein]

On Mon, Feb 14, 2022 at 3:00 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Mon, Feb 14, 2022 at 11:35 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
> >
> > On Feb 14 2022, H.J. Lu wrote:
> >
> > > On Mon, Feb 14, 2022 at 11:16 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
> > >>
> > >> On Feb 14 2022, H.J. Lu wrote:
> > >>
> > >> > On Mon, Feb 14, 2022 at 6:10 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
> > >> >>
> > >> >> I'm seeing erroneous behaviour with this.  There are random cases of
> > >> >> misbehaviour on build workers with AVX2, for example:
> > >> >>
> > >> >> https://build.opensuse.org/package/live_build_log/home:Andreas_Schwab:glibc/glibc:cross-riscv64/f/x86_64
> > >> >>
> > >> >> riscv64-suse-linux-gcc: error: unrecognized command-line option '-frounding-math'
> > >> >> make[2]: *** [../o-iterator.mk:9: /home/abuild/rpmbuild/BUILD/glibc-2.35.9000.58.g7912236f4a/cc-base/time/tzset.o] Error 1
> > >> >> make[2]: *** Waiting for unfinished jobs....
> > >> >
> > >> > How reproducible is it?
> > >>
> > >> 100%.
> > >>
> > >
> > > Can I reproduce it with scripts/build-many-glibcs.py on
> > > any machine which uses strcmp-avx2.S?
> >
> > Maybe.
> >
>
> I can't reproduce it.  It sounds very similar to
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=28646

Do you change the ifunc to prefer avx2?

>
> The failure can only be triggered by a specific setup.
> Noah, can you figure out what went wrong?

Looking into it. Andreas where can I see the build command you used?

>
> --
> H.J.