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 7D1873858D20; Fri, 31 Mar 2023 06:35:38 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7D1873858D20
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1680244538;
	bh=JTHzSKZko0vSlREFWdM9fnDSWK9kmYDsaDqUnnoqRpQ=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=JYVT4KnAlUAOV6MOZNiwppNyLYE/6oWfYmqS6dQn+2YTrpFpmY1+qPXD/MMi9N2TM
	 qp6xHrTAVLSg2pyHNQ/MgSLtqNxdyF2gn+iWTpEAV2KB/fj7nnvqHfl2KoxFs9Fa/d
	 BmXIzIKC8+uZ0vP8/GUb4Fx0qjIj9xfFE0Nx2ML4=
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109350] FAIL:
 g++.dg/warn/Wstringop-overflow-4.C
Date: Fri, 31 Mar 2023 06:35:38 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: diagnostic
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth 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: keywords blocked
Message-ID: <bug-109350-4-2OwPfLDvvp@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109350-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109350-4@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=3D109350

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Blocks|                            |88443

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
We have

<bb 2> [local count: 1073741824]:
_28 =3D{v} signed_value_source;
_4 =3D (unsigned long) _28;
_9 =3D _4 + 2147483648;
if (_9 > 4294967295)
  goto <bb 8>; [50.00%]
else
  goto <bb 3>; [50.00%]

<bb 3> [local count: 536870913]:
r_imin_imax_8 =3D (int) _28;
_31 =3D r_imin_imax_8 + 1;
_29 =3D (sizetype) _31;
if (_4 <=3D 4611686018427387900)
  goto <bb 4>; [50.00%]
else
  goto <bb 5>; [50.00%]

<bb 5> [local count: 268435458]:
_13 =3D operator new [] (18446744073709551615);
__builtin_memcpy (_13, &MEM <const char[37]> [(void
*)"0123456789abcdefghijklmnopqrstuvwxyz" + 35B], 2);
sink (_13);
if (_29 <=3D 4611686018427387900)
  goto <bb 9>; [100.00%]
else
  goto <bb 7>; [0.00%]

<bb 9> [local count: 0]:
iftmp.1_38 =3D _29 * 2;
_40 =3D operator new [] (iftmp.1_38);
__builtin_memcpy (_40, &MEM <const char[37]> [(void
*)"0123456789abcdefghijklmnopqrstuvwxyz" + 34B], 3);

and we're again down into get_size_range of the operator new[] argument
iftmp.1_38:

pointer-query.cc:507

    /* Determine the largest valid range size, including zero.  */
    if (!get_size_range (qry, size, stmt, r, SR_ALLOW_ZERO | SR_USE_LARGEST=
))
      return NULL_TREE;

where we compute

[irange] long unsigned int [0, 0] NONZERO 0x0$27 =3D void

for the range.  I have to make up my mind if that's correct, but ranger
debug prints the same conclusion so it doesn't seem to be an artifact of
using legacy value_range.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D88443
[Bug 88443] [meta-bug] bogus/missing -Wstringop-overflow warnings=