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 67C35385AC34; Tue,  8 Mar 2022 14:43:15 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 67C35385AC34
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/101910] [12 Regression] tsvc regressions for
 -O2 -ftree-loop-vectorize at zen hardware
Date: Tue, 08 Mar 2022 14:43:15 +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: 12.0
X-Bugzilla-Keywords: missed-optimization
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: 12.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-101910-4-uyP8JtIeFi@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-101910-4@http.gcc.gnu.org/bugzilla/>
References: <bug-101910-4@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
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Tue, 08 Mar 2022 14:43:15 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101910

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
https://lnt.opensuse.org/db_default/v4/CPP/latest_runs_report shows regress=
ions
for s422, in the GCC testsuite copy we do not vectorize this with -O2 since
it requires versioning for aliasing.

/home/rguenther/src/gcc3/gcc/testsuite/gcc.dg/vect/tsvc/vect-tsvc-s422.c:21=
:34:
missed:   versioning for alias required: can't determine dependence between
flat_2d_array[_1] and *_7
consider run-time aliasing test between flat_2d_array[_1] and *_7.  That's
because the code does

    xx =3D flat_2d_array + 4;

    for (int nl =3D 0; nl < 8*iterations; nl++) {
        for (int i =3D 0; i < LEN_1D; i++) {
            xx[i] =3D flat_2d_array[i + 8] + a[i];
        }
        dummy(a, b, c, d, e, aa, bb, cc, 0.);
    }

but 'dummy' is not known to not clobber 'xx'.  While xx is declared __restr=
ict
that dummy call still gets in the way.

So I wonder what variant LNT exactly benchmarks.=