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 9BA123858C60; Sun, 22 Aug 2021 09:20:23 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9BA123858C60
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/64537] Aarch64 redundant sxth instruction gets
 generated
Date: Sun, 22 Aug 2021 09:20:23 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 5.0
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: bug_status resolution target_milestone
Message-ID: <bug-64537-4-7E1D3iAzIK@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-64537-4@http.gcc.gnu.org/bugzilla/>
References: <bug-64537-4@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: Sun, 22 Aug 2021 09:20:23 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D64537

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |NEW
         Resolution|FIXED                       |---
   Target Milestone|9.0                         |---

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Well it was just this case that was fixed.
here is another one which is still broken:
unsigned int
adds_shift_ext ( unsigned long long a, unsigned short b, unsigned c)
{
 unsigned long long  d =3D (a - ((unsigned long long)b << 3));

  if (d =3D=3D 0)
    return a + c + b;
  else
    return b + d + c;
}

Note I think there is a missed reassociation/code hoisting too.

  <bb 3> [local count: 536870913]:
  _3 =3D (unsigned int) a_11(D);
  _4 =3D _3 + c_13(D);
  _15 =3D _4 + _8;
  goto <bb 5>; [100.00%]

  <bb 4> [local count: 536870913]:
  _7 =3D (unsigned int) d_12;
  _17 =3D _8 + c_13(D);
  _14 =3D _7 + _17;

c_13(D) + _8 is full redundant here=