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 8BC7A3858D37; Thu,  3 Feb 2022 02:45:16 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8BC7A3858D37
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/104360] Failure to optimize abs pattern
 (x^(x<0?-1:0)) - (x<0?-1:0)
Date: Thu, 03 Feb 2022 02:45:16 +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: enhancement
X-Bugzilla-Who: pinskia 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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: everconfirmed bug_severity short_desc keywords
 cf_reconfirmed_on bug_status
Message-ID: <bug-104360-4-DHfSPnT6E2@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-104360-4@http.gcc.gnu.org/bugzilla/>
References: <bug-104360-4@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: Thu, 03 Feb 2022 02:45:16 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104360

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
           Severity|normal                      |enhancement
            Summary|Failure to optimize abs     |Failure to optimize abs
                   |pattern on vector types     |pattern (x^(x<0?-1:0)) -
                   |                            |(x<0?-1:0)
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2022-02-03
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Even the scalar version is not optimized:
typedef short i16;

i16 abs_i16(i16 x)
{
    auto isN =3D -(x < 0);

    x ^=3D isN;
    return x - isN;
}

Shouldn't be too hard to optimize for both.

What is funny is clang/LLVM does not catch the scalar version either unless=
 you
do:
(x < i16{}) ? -1 : 0=