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 749583858C2C; Mon, 30 Aug 2021 05:18:43 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 749583858C2C
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/97756] [9/10/11/12 Regression] Inefficient
 handling of 128-bit arguments
Date: Mon, 30 Aug 2021 05:18:43 +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: 11.0
X-Bugzilla-Keywords: missed-optimization, ra
X-Bugzilla-Severity: normal
X-Bugzilla-Who: crazylht at gmail dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 9.5
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-97756-4-GcMdLhQC0q@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-97756-4@http.gcc.gnu.org/bugzilla/>
References: <bug-97756-4@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, 30 Aug 2021 05:18:43 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97756

--- Comment #7 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Patrick Palka from comment #3)
> Perhaps related to this PR: On x86_64, the following basic wrapper around
> int128 addition
>=20
>   __uint128_t f(__uint128_t x, __uint128_t y) { return x + y; }
>=20
> gets compiled (/w -O3, -O2 or -Os) to the seemingly suboptimal
>=20
>         movq    %rdi, %r9
>         movq    %rdx, %rax
>         movq    %rsi, %r8
>         movq    %rcx, %rdx
>         addq    %r9, %rax
>         adcq    %r8, %rdx
>         ret
>=20
> Clang does:
>=20
>         movq    %rdi, %rax
>         addq    %rdx, %rax
>         adcq    %rcx, %rsi
>         movq    %rsi, %rdx
>         retq

Remove addti3/ashlti3 from i386.md also helps this.=