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 22C93395540A; Thu,  4 Feb 2021 16:02:44 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 22C93395540A
From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/98465] [11 Regression] Bogus -Wstringop-overread
 with -std=gnu++20 -O2 and std::string::insert
Date: Thu, 04 Feb 2021 16:02:43 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 11.0
X-Bugzilla-Keywords: alias, diagnostic, missed-optimization, patch
X-Bugzilla-Severity: normal
X-Bugzilla-Who: msebor at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: msebor at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 11.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-98465-4-0vy1tQro7f@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-98465-4@http.gcc.gnu.org/bugzilla/>
References: <bug-98465-4@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
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Thu, 04 Feb 2021 16:02:44 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98465

--- Comment #23 from Martin Sebor <msebor at gcc dot gnu.org> ---
Having a built-in sit on top of a (for now internal?) attribute with the go=
al
of eventually exposing the attribute makes sense to me, although neither se=
ems
suitable to me for stage 4.

The patch I posted can be used to suppress the warning until then.  The pat=
ch
is needed in any case to solve pr98512 and pr98871.  Without the patch the
#pragma in libstdc++ doesn't work.

As an aside, an attribute that constrains aliasing won't just help std::str=
ing.
 It will improve the codegen for any container (see pr93971).=