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 812D23858C55; Tue, 20 Sep 2022 23:34:26 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 812D23858C55
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1663716866;
	bh=RI1Tu2tRJbF/T4sUbJBjI/XRTU0pCIlGrErd8L90wlw=;
	h=From:To:Subject:Date:From;
	b=ub3rmnzaVbAyr6utfgGwtPFuX9p0+utfO8LIVcOdjIx6clOEp0TrydK0AaoU7YBQe
	 5mUcTnelqqGq4zlswynSqu8ujC6sE1s9B6lCvKTVHTINmtx4PcJQ27Q3yHtKefO0AH
	 AggtDnKgIp/X1tFn3qAIjo4duxAmNF+7BOuE9HdM=
From: "kristerw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/106990] New: Missing TYPE_OVERFLOW_SANITIZED
 checks in match.pd
Date: Tue, 20 Sep 2022 23:34:26 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: kristerw 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: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-106990-4@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=3D106990

            Bug ID: 106990
           Summary: Missing TYPE_OVERFLOW_SANITIZED checks in match.pd
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kristerw at gcc dot gnu.org
  Target Milestone: ---

When UBSan is used, match.pd disables simplifications that can remove UB. B=
ut
two simplifications are missing TYPE_OVERFLOW_SANITIZED checks, making the =
two
tests below fail to report UB when compiled with -fsanitize=3Dundefined.

/* (~X - ~Y) -> Y - X.  */
int main(void)
{
  volatile int x =3D -1956816001;
  volatile int y =3D 1999200512;
  return ~x - ~y;
}

/* -x & 1 -> x & 1.  */
int main(void)
{
  volatile int x =3D 0x80000000;
  return -x & 1;
}=