From: Jonathan Wakely <jwakely@redhat.com>
To: Eric Botcazou <botcazou@adacore.com>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [committed] libstdc++: Fix compare_exchange_padding.cc test for std::atomic_ref
Date: Tue, 1 Nov 2022 13:53:46 +0000 [thread overview]
Message-ID: <CACb0b4kRt=rjcKzFym8DZbHkZ1T5we8MiTQf6UMqgHWb5VWw1A@mail.gmail.com> (raw)
In-Reply-To: <CACb0b4mCn-1vDJxpkH04gLM250=6WxUsjHofFw2qOsqyjZOAaQ@mail.gmail.com>
On Mon, 31 Oct 2022 at 17:05, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Mon, 31 Oct 2022 at 17:03, Eric Botcazou <botcazou@adacore.com> wrote:
> >
> > > I suppose we could use memcmp on the as variable itself, to inspect
> > > the actual stored padding rather than the returned copy of it.
> >
> > Yes, that's probably the only safe stance when optimization is enabled.
>
>
> Strictly speaking, it's not safe, because it's undefined to use memcmp
> on an object of a non-trivial type. But it should work.
Do those loads still get scalarized at -O0?
next prev parent reply other threads:[~2022-11-01 13:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 20:21 Jonathan Wakely
2022-10-31 15:34 ` Eric Botcazou
2022-10-31 15:37 ` Jonathan Wakely
2022-10-31 17:03 ` Eric Botcazou
2022-10-31 17:05 ` Jonathan Wakely
2022-11-01 13:53 ` Jonathan Wakely [this message]
2022-11-01 15:26 ` Eric Botcazou
2023-09-01 15:21 ` Jonathan Wakely
2023-09-01 18:14 ` Eric Botcazou
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