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 D2A5C385780D; Wed, 30 Sep 2020 06:30:22 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D2A5C385780D
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/97249] New: Missing vec_select and subreg
 optimization
Date: Wed, 30 Sep 2020 06:30:22 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
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: UNCONFIRMED
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_id short_desc product version bug_status
 keywords bug_severity priority component assigned_to reporter cc
 target_milestone cf_gcchost
Message-ID: <bug-97249-4@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: Wed, 30 Sep 2020 06:30:22 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97249

            Bug ID: 97249
           Summary: Missing vec_select and subreg optimization
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: crazylht at gmail dot com
                CC: hjl.tools at gmail dot com, wwwhhhyyy333 at gmail dot c=
om
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu

Cat test.c
---
void
foo (unsigned char* p1, unsigned char* p2, short* __restrict p3)
{
    for (int i =3D 0 ; i !=3D 8; i++)
     p3[i] =3D p1[i] + p2[i];
     return;
}
---

gcc11 -Ofast -mavx2 test.c  got

---
foo:
.LFB0:
        .cfi_startproc
        vmovq   (%rdi), %xmm0
        vmovq   (%rsi), %xmm1
        vpmovzxbw       %xmm0, %xmm0
        vpmovzxbw       %xmm1, %xmm1
        vpaddw  %xmm1, %xmm0, %xmm0
        vmovdqu %xmm0, (%rdx)
        ret
        .cfi_endproc
---

memory operand doesn't propagate into *vpmovzxbw* because rtl didn't simpli=
fy
---
(insn 9 8 10 2 (set (reg:V8HI 92 [ vect__33.6 ])
        (zero_extend:V8HI (vec_select:V8QI (subreg:V16QI (reg:V8QI 91 [
vect__40.5 ]) 0)
                (parallel [
                        (const_int 0 [0])
                        (const_int 1 [0x1])
                        (const_int 2 [0x2])
                        (const_int 3 [0x3])
                        (const_int 4 [0x4])
                        (const_int 5 [0x5])
                        (const_int 6 [0x6])
                        (const_int 7 [0x7])
                    ])))) "test.c":5:16 4638 {sse4_1_zero_extendv8qiv8hi2}
     (expr_list:REG_DEAD (reg:V8QI 91 [ vect__40.5 ])
        (nil)))
---=20

to=20

---
(insn 9 8 10 2 (set (reg:V8HI 92 [ vect__33.6 ])
        (zero_extend:V8HI (reg:V8QI 91 [ vect__40.5 ])))) "test.c":5:16 4638
{sse4_1_zero_extendv8qiv8hi2}
     (expr_list:REG_DEAD (reg:V8QI 91 [ vect__40.5 ])
        (nil)))
---

Similar for other vector modes.=