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 CE08C3858416; Sun,  5 Sep 2021 07:01:16 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org CE08C3858416
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/89954] missed optimization for signed extension for x86-64
Date: Sun, 05 Sep 2021 07:01:16 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 8.3.0
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_severity
Message-ID: <bug-89954-4-0t3XAkLk82@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-89954-4@http.gcc.gnu.org/bugzilla/>
References: <bug-89954-4@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, 05 Sep 2021 07:01:16 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D89954

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So at combine we have:
(insn 5 2 6 2 (set (reg:QI 87 [ c ])
        (mem/c:QI (symbol_ref:DI ("c") [flags 0x2]  <var_decl 0x7fc1a1d62c60
c>) [0 c+0 S1 A8])) "/app/example.cpp":5:14 77 {*movqi_internal}
     (nil))
(insn 6 5 7 2 (parallel [
            (set (reg:QI 86)
                (xor:QI (reg:QI 87 [ c ])
                    (const_int 1 [0x1])))
            (clobber (reg:CC 17 flags))
        ]) "/app/example.cpp":5:14 546 {*xorqi_1}
     (expr_list:REG_DEAD (reg:QI 87 [ c ])
        (expr_list:REG_UNUSED (reg:CC 17 flags)
            (expr_list:REG_EQUAL (xor:QI (mem/c:QI (symbol_ref:DI ("c") [fl=
ags
0x2]  <var_decl 0x7fc1a1d62c60 c>) [0 c+0 S1 A8])
                    (const_int 1 [0x1]))
                (nil)))))
(insn 7 6 12 2 (set (reg:SI 85)
        (sign_extend:SI (reg:QI 86))) "/app/example.cpp":5:14 154 {extendqi=
si2}
     (expr_list:REG_DEAD (reg:QI 86)
        (nil)))

The load is not loaded into the full SI/DI register yet. The change to SI m=
ode
for xor happens after reload in split2.

So yes it is a target issue.=