From: Jonathan Wakely <jwakely@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: xndcn <xndchn@gmail.com>, Xi Ruoyao <xry111@xry111.site>,
"H.J. Lu" <hjl.tools@gmail.com>,
GCC Patches <gcc-patches@gcc.gnu.org>,
libstdc++@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: atomic: Add missing clear_padding in __atomic_float constructor
Date: Fri, 16 Feb 2024 15:15:24 +0000 [thread overview]
Message-ID: <CACb0b4kSc1AU30Yrz+vKVCjC5t=QgTLBeHvaMRywKOP=HkLLig@mail.gmail.com> (raw)
In-Reply-To: <Zc9suet5yfTm0k0A@tucnak>
On Fri, 16 Feb 2024 at 14:10, Jakub Jelinek wrote:
>
> On Fri, Feb 16, 2024 at 01:51:54PM +0000, Jonathan Wakely wrote:
> > Ah, although __atomic_compare_exchange only takes pointers, the
> > compiler replaces that with a call to __atomic_compare_exchange_n
> > which takes the newval by value, which presumably uses an 80-bit FP
> > register and so the padding bits become indeterminate again.
>
> __atomic_compare_exchange_n only works with integers, so I guess
> it is doing VIEW_CONVERT_EXPR (aka union-style type punning) on the
> argument.
>
> Do you have preprocessed source for the testcase?
Sent offlist.
next prev parent reply other threads:[~2024-02-16 15:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAJ=gGT3=TCsF2GcsawmbOReDjwVPmxpSLw1_CTZX5NE6HUtu+g@mail.gmail.com>
[not found] ` <CAMe9rOrm4=d5xkHeocOFNWf4=vUfwc_bzp4_zUt8j8+apcrWoA@mail.gmail.com>
[not found] ` <CAJ=gGT1LwAeKF6B5eNFBdKXzeK9Z1ubAwH-ykS_2X2Fc9t7-Ww@mail.gmail.com>
2024-01-16 10:12 ` Xi Ruoyao
2024-01-16 16:16 ` xndcn
2024-01-24 15:53 ` xndcn
2024-01-30 16:08 ` [PING][PATCH] " xndcn
2024-01-30 16:31 ` [PATCH] " Jonathan Wakely
2024-01-30 16:34 ` Jonathan Wakely
2024-01-30 16:50 ` Jakub Jelinek
2024-01-31 17:19 ` xndcn
2024-02-01 13:54 ` Jonathan Wakely
2024-02-02 16:52 ` xndcn
2024-02-16 12:38 ` Jonathan Wakely
2024-02-16 13:51 ` Jonathan Wakely
2024-02-16 14:10 ` Jakub Jelinek
2024-02-16 15:15 ` Jonathan Wakely [this message]
2024-03-14 15:13 ` Jonathan Wakely
2024-03-25 15:42 ` [PING][PATCH] " xndcn
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