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 CD6873844062; Fri, 16 Apr 2021 22:31:17 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org CD6873844062
From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/93100] gcc -fsanitize=address inhibits -Wuninitialized
Date: Fri, 16 Apr 2021 22:31:17 +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: 9.2.1
X-Bugzilla-Keywords: diagnostic
X-Bugzilla-Severity: normal
X-Bugzilla-Who: msebor at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: msebor at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cf_known_to_fail cc component cf_reconfirmed_on
 bug_status dependson assigned_to
Message-ID: <bug-93100-4-plYIOHjnAI@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-93100-4@http.gcc.gnu.org/bugzilla/>
References: <bug-93100-4@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: Fri, 16 Apr 2021 22:31:17 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D93100

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |10.2.1, 11.0, 9.3.0
                 CC|                            |msebor at gcc dot gnu.org
          Component|sanitizer                   |middle-end
   Last reconfirmed|2020-01-09 00:00:00         |2021-4-16
             Status|NEW                         |ASSIGNED
         Depends on|                            |98508
           Assignee|unassigned at gcc dot gnu.org      |msebor at gcc dot g=
nu.org

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Reconfirming with GCC 11.  The reason for the false negative is that
instrumentation functions injected by the sanitizers look to the warning li=
ke
they might initialize the variables.  That's simply because the warning has=
n't
been taught they're special and don't write to the variables.  The patch in
pr98508 comment 5 enables the warning.  Let me submit it for GCC 12.

void f ()
{
  struct A b;
  struct A a;
  int _1;

  <bb 2> :
  # .MEM_4 =3D VDEF <.MEM_3(D)>
  .ASAN_MARK (UNPOISON, &a, 8);   <<< assumed to write to a
  # VUSE <.MEM_4>
  _1 =3D a.i;                       <<< missing warning
  if (_1 !=3D 0)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
  # .MEM_5 =3D VDEF <.MEM_4>
  b =3D a;

  <bb 4> :
  # .MEM_2 =3D PHI <.MEM_4(2), .MEM_5(3)>
  # .MEM_6 =3D VDEF <.MEM_2>
  .ASAN_MARK (POISON, &a, 8);
  # VUSE <.MEM_6>
  return;

}


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98508
[Bug 98508] Sanitizer disable -Wall and -Wextra=