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 177423858D32; Sat,  1 Oct 2022 14:27:04 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 177423858D32
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1664634424;
	bh=3pcpSibnyISgulVgvZaSZokeGbmHMukkLzove0rkUII=;
	h=From:To:Subject:Date:From;
	b=MYZIYBP6EpyUdjp6Bp9AzjmVuIrVnPeteivB2o0zaRSw1Hrz8DF/56PtzNls5xovZ
	 vTo2+7xODzBZG6SzuetL0nllOq9KZUBuOHeiX+uAHOMxv3h2ytsRSjYiMol00h6tHg
	 n+p9/QesD6WQaxwnMSw54XiuutU2fSzqH749Q/Is=
From: "zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug debug/107110] New: failure (length) with -fcompare-debug at -O1
 and above
Date: Sat, 01 Oct 2022 14:27:03 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: debug
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-107110-4@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=3D107110

            Bug ID: 107110
           Summary: failure (length) with -fcompare-debug at -O1 and above
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a regression from 10.* and affect 11.* and later.=20

Compiler Explorer: https://godbolt.org/z/Gvh15c5KE

[529] % 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/13.0.0/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
--with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221001 (experimental) [master r13-3010-g2555071c954] (=
GCC)=20
[530] %=20
[530] % gcctk -O1 -fcompare-debug small.c
gcctk: error: small.c: =E2=80=98-fcompare-debug=E2=80=99 failure (length)
[531] %=20
[531] % cat small.c
int a, b;
void c() {
  int d, e =3D 1, f =3D 1, g, h =3D 0;
  for (; 1; h++) {
    if (d)
      f =3D 0;
    if (d)
      break;
    if (g)
      goto L;
    g =3D f;
  }
  for (; h < 1;)
  L:
    for (;;) {
      int j, k =3D e;
      if (a) {
        break;
        ;
      }
      e =3D 0;
      while (b <=3D k)
        ;
      break;
      &j;
    }
}
int main() {
  if (a)
    c();
  return 0;
}=