From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-348879-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 6139 invoked by alias); 2 Mar 2011 15:17:52 -0000
Received: (qmail 6130 invoked by uid 22791); 2 Mar 2011 15:17:51 -0000
X-SWARE-Spam-Status: No, hits=-2.9 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 02 Mar 2011 15:17:48 +0000
From: "vincent at vinc17 dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/36299] spurious and undocumented warning with -Waddress for a == 0 when a is an array
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: vincent at vinc17 dot org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-36299-4-UmUxw3BlZE@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-36299-4@http.gcc.gnu.org/bugzilla/>
References: <bug-36299-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Date: Wed, 02 Mar 2011 15:17:00 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2011-03/txt/msg00192.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D36299

--- Comment #9 from Vincent Lef=C3=A8vre <vincent at vinc17 dot org> 2011-0=
3-02 15:17:33 UTC ---
(In reply to comment #8)
> Every warning warns about something valid in C, otherwise it would be an =
error
> not a warning.

No, for instance:

int main(void)
{
  int i;
  return i;
}

This is undefined behavior and detected by GCC, but one gets only a warning:

tst.c: In function =E2=80=98main=E2=80=99:
tst.c:4: warning: =E2=80=98i=E2=80=99 is used uninitialized in this function

Compare to a =3D=3D 0 in the above testcase, which has a well-defined behav=
ior.