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 74C093858C56; Tue, 21 Jun 2022 14:39:07 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 74C093858C56
From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106022] [12/13 Regression] Enable vectorizer generates
 extra load
Date: Tue, 21 Jun 2022 14:39:07 +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: 12.1.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: hjl.tools 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: 12.2
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-106022-4-s31nq0Asq3@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-106022-4@http.gcc.gnu.org/bugzilla/>
References: <bug-106022-4@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: Tue, 21 Jun 2022 14:39:07 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106022

--- Comment #9 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Richard Biener from comment #8)
> (In reply to H.J. Lu from comment #6)
> > Created attachment 53169 [details]
> > A patch
> >=20
> > This patch multiplies the vector store cost by the number of scalar ele=
ments
> > in
> > a word to properly compare scalar store cost against vector store cost.
>=20
> But that's not "properly" but "wrong" ...
>=20
> Note we already cost the vector load from the constant pool so the vector
> side costing is correct.
>=20
> What's eventually imprecise is the scalar cost where you could anticipate
> store merging, but adjusting the vector cost side is just wrong.

I tried to adjust the scalar cost.  When the scalar cost of storing a byte
is 6, dividing it by 8 (the number of scalar elements in a word) becomes 0.
Will it work?=