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 9096C3853D56; Mon, 21 Nov 2022 13:18:47 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9096C3853D56
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1669036727;
	bh=NjjgmWRjg5ezVJzW69aGlSssT19jHYQXKrTWPUyXJ5w=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=csf6XBUa9DPr7sT/LWmYxAXTFCI6PMuOL6vDBGa2BhuRs9uhT7vEIZy3C6uHG/0Y2
	 72Z/gMsRGI0X33ZyI4B+7BEbK+Gt4EEoPOT0fyAtN/eARx5LnuDZr2ypgulGfYJAxH
	 2hx8boKQpMIuy46730+OOHkSvD7h8l328eYNoShQ=
From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/104088] [12/13 Regression] '-O2' (or higher) GCN
 offloading (only) 'libgomp.oacc-c-c++-common/vprop.c' excess errors:
 'warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]'
Date: Mon, 21 Nov 2022 13:18:46 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 12.0
X-Bugzilla-Keywords: diagnostic, openacc
X-Bugzilla-Severity: normal
X-Bugzilla-Who: burnus at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.3
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-104088-4-fgulRvrzNk@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-104088-4@http.gcc.gnu.org/bugzilla/>
References: <bug-104088-4@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=3D104088

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu.org

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
I did have a look at this the other day. If I recall correctly, the issue w=
as
that

  tree destsize =3D compute_objsize (dest, stmt, ostype, &aref, &ptr_qry);

in strlen_pass::maybe_warn_overflow (in file tree-ssa-strlen.cc) wrongly
returned 0
for a   var[i]._char_memb. Somewhere ('var'?) was a variable which did not =
use
the 64bit generic memory space but a 32-byte one. My feeling is that the
problem is related to having a non-generic memory space.

(Disclaimer: It was a couple of days back when I had a quick look and I mig=
ht
misremember. The 'var[i]._char_memb' matches pattern wise but the name was
surely different.)

However, reading now the commit message title, quoted in comment 0 - "Use
enclosing object size if it's smaller than member" -, explains why the 1-by=
te
character type's length is not used even if it looks fine.=