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 0C46B385783D; Mon,  7 Dec 2020 12:19:05 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0C46B385783D
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/98167] [x86] Failure to optimize operation on
 indentically shuffled operands into a shuffle of the result of the operation
Date: Mon, 07 Dec 2020 12:19:04 +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: 11.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: crazylht at gmail dot com
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: 
Message-ID: <bug-98167-4-RusfeHhfqr@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-98167-4@http.gcc.gnu.org/bugzilla/>
References: <bug-98167-4@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: Mon, 07 Dec 2020 12:19:05 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98167

--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
;; _3 =3D __builtin_ia32_shufps (b_2(D), b_2(D), 0);

(insn 7 6 8 (set (reg:V4SF 88)
        (reg/v:V4SF 86 [ b ])) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))

(insn 8 7 9 (set (reg:V4SF 89)
        (reg/v:V4SF 86 [ b ])) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))

(insn 9 8 10 (set (reg:V4SF 87)
        (vec_select:V4SF (vec_concat:V8SF (reg:V4SF 88)
                (reg:V4SF 89))
            (parallel [
                    (const_int 0 [0]) repeated x2
                    (const_int 4 [0x4]) repeated x2
                ]))) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))
;; _5 =3D __builtin_ia32_shufps (a_4(D), a_4(D), 0);

(insn 11 10 12 (set (reg:V4SF 91)
        (reg/v:V4SF 85 [ a ])) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))

(insn 12 11 13 (set (reg:V4SF 92)
        (reg/v:V4SF 85 [ a ])) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))

(insn 13 12 14 (set (reg:V4SF 90)
        (vec_select:V4SF (vec_concat:V8SF (reg:V4SF 91)
                (reg:V4SF 92))
            (parallel [
                    (const_int 0 [0]) repeated x2
                    (const_int 4 [0x4]) repeated x2
                ]))) "./gcc/include/xmmintrin.h":746:19 -1
     (nil))


Simplify upper to

(vec_duplicate:V4SF
  (vec_select:SF (reg:V4SF 86)
                 (parallel [(const_int 0)])

then add a combine splitter transform (mult:(vec_dup op1) (vec_dup op2)) to
(vec_dup (mult:op1 op2)?=