From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 99A1C384F4A0; Thu, 15 Feb 2024 11:44:24 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 99A1C384F4A0
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1707997464;
	bh=o6N5UK2UJ4Xi85YmM2YK1FB6gVFr242ko71UtUF4lzI=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=IzFO/jI/c2kRwIOqiTDFXUueSSuefPSLTOc+3DFASfziFurURXG9B9XmxGYZHB84Q
	 Us5EPWJHKQJg78NpzkwfNL/VSE84fTRMVoQkbZIbS7WDLCB3CfIgeC0ck4ULFod98O
	 kyjcyU9K6MMpr2ZlRau3leNPCC0PlQ2E2KzRtIXo=
From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/99117] [11/12/13/14 Regression] cannot accumulate
 std::valarray
Date: Thu, 15 Feb 2024 11:44:18 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 10.1.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: cvs-commit at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 11.5
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-99117-4-bWYzKnAbyO@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-99117-4@http.gcc.gnu.org/bugzilla/>
References: <bug-99117-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99117

--- Comment #23 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:b58f0e5216a3053486e7f1aa96c3f2443b14d630

commit r14-9000-gb58f0e5216a3053486e7f1aa96c3f2443b14d630
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Feb 8 13:59:42 2024 +0000

    libstdc++: Avoid aliasing violation in std::valarray [PR99117]

    The call to __valarray_copy constructs an _Array object to refer to
    this->_M_data but that means that accesses to this->_M_data are through
    a restrict-qualified pointer. This leads to undefined behaviour when
    copying from an _Expr object that actually aliases this->_M_data.

    Replace the call to __valarray_copy with a plain loop. I think this
    removes the only use of that overload of __valarray_copy, so it could
    probably be removed. I haven't done that here.

    libstdc++-v3/ChangeLog:

            PR libstdc++/99117
            * include/std/valarray (valarray::operator=3D(const _Expr&)):
            Use loop to copy instead of __valarray_copy with _Array.
            * testsuite/26_numerics/valarray/99117.cc: New test.=