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 33F163857C48; Wed,  2 Sep 2020 18:57:19 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 33F163857C48
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
 s=default; t=1599073039;
 bh=mnjz+hFj0neS/Kh4tdcOCjRJA7WYuUr3t/yRYnAt6oQ=;
 h=From:To:Subject:Date:In-Reply-To:References:From;
 b=YsOqMkXEhLRHDnW9BZcGR4RSOrCNDQVNLCvkrC9YPORYa9p40/j5OPyRsmFiHT/cf
 eEaJCZeQ8KyxEeqLMa0OocupmEXF1pDUD5704zcWitQS+hNCv5q/xSQlaEPFcAvWrA
 4K1buV0ir5ChJ40y/MPYu63O2RKGfvhUwSApz0MM=
From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/96900] [9/10/11 Regression] bogus -Warray-bounds on
 strlen with valid pointer obtained from just-past-the-end
Date: Wed, 02 Sep 2020 18:57:19 +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: diagnostic
X-Bugzilla-Severity: normal
X-Bugzilla-Who: msebor at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-96900-4-2V5DSh66rn@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-96900-4@http.gcc.gnu.org/bugzilla/>
References: <bug-96900-4@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: Wed, 02 Sep 2020 18:57:19 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D96900

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
The underlying cause is fold_nonarray_ctor_reference() returning a scalar z=
ero
for apparently out-of-bounds references when determining the initializer for
s.a from &s.a[sizeof s.a].  Its caller, constant_byte_string(), then interp=
rets
that as an array of single element initialized to zero, but it incorrectly
returns the offset from the beginning of s (i.e., 4 rather than 3 minus 3 f=
or
sizeof s.a).   Its caller, c_strlen(), then uses the size of the one-element
initializer (for "") and the offset (positive 1) as the basis for issuing t=
he
warning.=