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 DDD913858D20; Fri, 17 May 2024 07:08:50 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DDD913858D20
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1715929730;
	bh=+3XMpdtDweyJ6EvA9bU3s4A1fQD/8ot0IzkGQyxNOdM=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=xO7SQpP6ecpUv9ti2t3HsWnrgixBCWySZ93RpJ6TD7Toa5876AoQasYyIX9WvFcIX
	 mzhhiKRbM4xpc0eWnFa+kvNQ8vZO9JeEwGxAixfX+kgCcpna9/wzXY/k8vyTMsLRrl
	 4Mpr7/xk5F42tPl6cXaM4YPabkfrBLpHnRfqBtQQ=
From: "haochen.jiang at intel dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/115069] [14/15 regression] 8 bit integer vector
 performance regression, x86, between gcc-14 and gcc-13 using avx2 target
 clones on skylake platform
Date: Fri, 17 May 2024 07:08:50 +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: 14.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: haochen.jiang at intel 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: 14.2
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-115069-4-gJJQsP8Lv7@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-115069-4@http.gcc.gnu.org/bugzilla/>
References: <bug-115069-4@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
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D115069

--- Comment #6 from Haochen Jiang <haochen.jiang at intel dot com> ---
(In reply to Hongtao Liu from comment #5)
> (In reply to Krzysztof Kanas from comment #4)
> > I bisected the issue and it seems that commit
> > 0368fc54bc11f15bfa0ed9913fd0017815dfaa5d introduces regression.
>=20
> I guess the real guilty commit is=20
>=20
> commit 52ff3f7b863da1011b73c0ab3b11f6c78b6451c7
> Author: Uros Bizjak <ubizjak@gmail.com>
> Date:   Thu May 25 19:40:26 2023 +0200
>=20=20
>     i386: Use 2x-wider modes when emulating QImode vector instructions
>=20=20
>     Rewrite ix86_expand_vecop_qihi2 to expand fo 2x-wider (e.g. V16QI ->
> V16HImode)
>     instructions when available.  Currently, the compiler generates follo=
wing
>     assembly for V16QImode multiplication (-mavx2):

Yes, since 0368fc54bc11f15bfa0ed9913fd0017815dfaa5d only fixed a typo in th=
at
patch.

Original thread: https://gcc.gnu.org/pipermail/gcc-patches/2023-May/619745.=
html=