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 823A8389942A; Fri, 29 Apr 2022 12:30:08 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 823A8389942A
From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/105429] Unnecessary moves generated with _mm_crc32_u64
Date: Fri, 29 Apr 2022 12:30:08 +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: 13.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: ubizjak 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: 
Message-ID: <bug-105429-4-hpuHsx7RBL@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-105429-4@http.gcc.gnu.org/bugzilla/>
References: <bug-105429-4@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: Fri, 29 Apr 2022 12:30:08 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105429

--- Comment #1 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
The intrinsic is defined as:

unsinged __int64 _mm_crc32_u64( unsinged __int64 crc, unsigned __int64 data=
 )

and the unnecessary move is in fact zero-extend:

        movl    %eax, %eax      # 16    [c=3D1 l=3D2]  *zero_extendsidi2/3

You probably want:

uint32_t crc(uint64_t current, const uint8_t *buffer, size_t size) {
    for(size_t i =3D 0; i < size; i++)
        current =3D _mm_crc32_u64(current, buffer[i]);
    return current;
}=