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 7441E384144C; Tue, 21 Jun 2022 06:41:10 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7441E384144C
From: "rguenth at gcc dot gnu.org" <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 06:41:10 +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: rguenth at gcc dot gnu.org
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-106022-4-2NoqZd8rYc@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 06:41:10 -0000

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

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(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 eleme=
nts
> in
> a word to properly compare scalar store cost against vector store cost.

But that's not "properly" but "wrong" ...

Note we already cost the vector load from the constant pool so the vector
side costing is correct.

What's eventually imprecise is the scalar cost where you could anticipate
store merging, but adjusting the vector cost side is just wrong.=