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 0FC1C3858D37; Sat, 20 Apr 2024 10:53:09 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0FC1C3858D37
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1713610389;
	bh=v0mDUCEORm0t5QhcxGYiaLpvZ6RA/4Kmg2L4cOm0U0I=;
	h=From:To:Subject:Date:From;
	b=THBT7rVHJDaq13kQobErAhSKU7vXk1Y8DtYiIaOD2p3vQ9TR7jHJlg3mcR8JmfiAa
	 nAcY/O0s2qXlJYzmnKcjx5UmMyc67ybkyj/9U6qlM8IBw/ScVdJIgQsKyshcRF8s0X
	 /NLBE4QBK0oLroLCP6IyztAceA6F5H9yyDLIszYk=
From: "zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114787] New: wrong code at -O1 on
 x86_64-linux-gnu (the generated code hangs)
Date: Sat, 20 Apr 2024 10:53:07 +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: unknown
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: zhendong.su at inf dot ethz.ch
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-114787-4@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=3D114787

            Bug ID: 114787
           Summary: wrong code at -O1 on x86_64-linux-gnu (the generated
                    code hangs)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a recent regression and does not reproduce with 13.2 and
earlier.=20

Compiler Explorer: https://godbolt.org/z/6sbh8Wr1e


[663] % gcctk -v
Using built-in specs.
COLLECT_GCC=3Dgcctk
COLLECT_LTO_WRAPPER=3D/local/suz-local/software/local/gcc-trunk/libexec/gcc=
/x86_64-pc-linux-gnu/14.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=3Dyes --prefix=3D/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=3Dc,c++ --disable-werror --enable-mu=
ltilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.1 20240420 (experimental) (GCC)=20
[664] %=20
[664] % gcctk -O0 small.c; ./a.out
[665] %=20
[665] % gcctk -O1 small.c
[666] % timeout -s 9 10 ./a.out
Killed
[667] %=20
[667] % cat small.c
int a, b, c, d, e =3D -1, f, g, h, j, k, n, o, p;
int main() {
  int i, l =3D 2, m;
  for (b =3D 0; b < 1; b++)
    l =3D 0;
  for (; a >=3D 0; a--)
    for (m =3D 3; m; m--) {
      k =3D g;
      i =3D 0;
      for (; i < 1; i++)
        for (; f < 1; f++)
          h =3D g;
      n =3D 2 & ((e ^ d) | 1) * j;
      o =3D ~(e & n);
    q:
      if (c <=3D e)
        return 0;
      e =3D o;
    }
  p =3D l;
  l =3D 0;
  if (p)
    goto q;
  return 0;
}=