From: Christophe Lyon <christophe.lyon@linaro.org>
To: Jonathan Wakely <jwakely@redhat.com>
Cc: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Remove some more unconditional uses of atomics
Date: Thu, 14 Sep 2023 10:41:12 +0200 [thread overview]
Message-ID: <CAPS5khafJ94qRQjEA6gActTbv6LYk0xapVe2ro5AghWj_tih8g@mail.gmail.com> (raw)
In-Reply-To: <CACb0b4mjyOnBJgYJD9JfPziB2FxLWCn_Ng-tui=j3LpM+kVGEA@mail.gmail.com>
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On Thu, 14 Sept 2023 at 10:17, Jonathan Wakely <jwakely@redhat.com> wrote:
> On Thu, 14 Sept 2023 at 08:44, Christophe Lyon
> <christophe.lyon@linaro.org> wrote:
> >
> > Hi,
> >
> >
> > On Wed, 13 Sept 2023 at 14:32, Jonathan Wakely <jwakely@redhat.com>
> wrote:
> >>
> >> Tested x86_64-linux and aarch64-linux. I intend to push this to trunk.
> >>
> >> -- >8 --
> >>
> >> These atomics cause linker errors on arm4t where __sync_synchronize is
> >> not defined. For single-threaded targets we don't need the atomics.
> >>
> >
> > I ran the tests on arm-eabi default config (so, armv4t) with this patch,
> and here is the list of remaining UNRESOLVED tests:
> > 29_atomics/atomic/compare_exchange_padding.cc
> > 29_atomics/atomic/cons/value_init.cc
> > 29_atomics/atomic_float/value_init.cc
> > 29_atomics/atomic_integral/cons/value_init.cc
> > 29_atomics/atomic_ref/compare_exchange_padding.cc
> > 29_atomics/atomic_ref/generic.cc
> > 29_atomics/atomic_ref/integral.cc
> > 29_atomics/atomic_ref/pointer.cc
> > experimental/polymorphic_allocator/construct_pair.cc
> >
> > all of them are due to undefined reference to __sync_synchronize
> > (some also reference __atomic_compare_exchange_4, etc...)
> >
> >
> > IIUC, this should not be the case for
> experimental/polymorphic_allocator/construct_pair.cc ?
> > The reference for __sync_synchronize is near the beginning of test0[123]
> > from a call to __atomic_load_n line 835 of atomic_base.h
> > not sure where it comes from, the .loc directive indicates line 28 of
> the testcase which is the opening brace
>
> Doh, I removed the atomics from <memory_resource> but this is
> <experimental/memory_resource>, which has a separate implementation.
>
> I'll make a change to <experimental/memory_resource> as well, thanks
> for catching my silly mistake.
>
>
You're welcome.
So I'll shrink my patch and add dg-require-thread-fence only to the few
29_atomics tests listed above.
Christophe
next prev parent reply other threads:[~2023-09-14 8:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 12:31 Jonathan Wakely
2023-09-14 7:43 ` Christophe Lyon
2023-09-14 8:17 ` Jonathan Wakely
2023-09-14 8:41 ` Christophe Lyon [this message]
2023-09-14 9:06 ` Jonathan Wakely
2023-09-14 9:11 ` Christophe Lyon
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