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 98870384F88C; Fri, 25 Nov 2022 10:33:09 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 98870384F88C
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1669372389;
	bh=LeQjQQBExL1/aZX/HCgCpuSFp7juos1l/M7QDrXn/wQ=;
	h=From:To:Subject:Date:From;
	b=fM0yJEGCVjJvgJq6bBE039ZhrIU5zB3wqR9EF1lom+oQOF2cE5TfT1gt+b/E6nqzr
	 9hq2GJrYP8qcBWgIklr5jJ+hqAc4cvLPIk7L/Kn0QMRXFgijKF/fXiJYjZ4nxXBYjl
	 5Uf5WkEZOGYbvgg/nTUzbk3SeIMyZUiJFSXwIXwI=
From: "victor.donascimento at arm dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107868] New: [10 regression] Wrong code on
 AArch64 at -O1 with new/delete
Date: Fri, 25 Nov 2022 10:33:09 +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: 10.4.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: victor.donascimento at arm dot com
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-107868-4@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=3D107868

            Bug ID: 107868
           Summary: [10 regression] Wrong code on AArch64 at -O1 with
                    new/delete
           Product: gcc
           Version: 10.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: victor.donascimento at arm dot com
  Target Milestone: ---

The libstdc++ execution test 20_util/allocator/1.cc test fails on the head =
of
the gcc-10 release branch when compiled at at the -O1 optimization level.

The cddce1 tree dump reports the following elimination:

Eliminating unnecessary statements:=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20
Deleting : _4 =3D ~check_delete.1_3;=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20
Deleting : operator delete (_11, 256);
Deleting : _2 =3D ~check_new.0_1;=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20
Deleting : _11 =3D operator new (256);

leading to the spurious loss of calls to both the new and delete operators.

bisecting between basepoints/gcc-10 and basepoints/gcc-11 identified the
following commit as introducing the error:

r10-2217-g8e8e7af514344588ff3e3da25c0cb74c12dc6a0d
Author: Martin Liska <mliska@suse.cz>
Date:   Fri Aug 2 08:07:15 2019 +0200

    Mark DECL_SET_IS_OPERATOR_DELETE for user-provided delete operators.

and the following as fixing the bug:

r11-3611-g0b945f959f03a6185a3130f30bfd524d01d4142c
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Oct 1 10:44:27 2020 +0200

    make use of CALL_FROM_NEW_OR_DELETE_P

Is the above patch an appropriate fix for the issue or does it mask any fur=
ther
shortcommings in the compiler?

If we're happy with the fix, should it be backported to GCC 10?
Many thanks.

Here is a reduced testcase:

#include <memory>

struct gnu { };
bool check_new =3D false;
bool check_delete =3D false;

void*
operator new(std::size_t n) noexcept(false)
{
  check_new =3D true;
  return NULL;
}

void operator delete(void *v) noexcept
{
  check_delete =3D true;
  return;
}

void operator delete(void *v, std::size_t) noexcept
{
  ::operator delete(v);
}

void test01()
{
  std::allocator<gnu> obj;

  if (!check_new)
    __builtin_abort();

  obj.deallocate(pobj, 256);
  if (!check_delete)
    __builtin_abort();
}

int main()
{
  test01();
  return 0;
}=