From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id BBD00393AC1F; Mon, 21 Jun 2021 12:42:53 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BBD00393AC1F From: "wschmidt at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/100866] PPC: Inefficient code for vec_revb(vector unsigned short) < P9 Date: Mon, 21 Jun 2021 12:42:53 +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: 8.3.1 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: wschmidt 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: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jun 2021 12:42:53 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100866 --- Comment #10 from Bill Schmidt --- Right, it would be a good optimization. We've stopped focusing much on P8 optimization work at this point simply because of lack of resources. The needed transform is to recognize load-xxlnor-vperm as a group and combi= ne into invload-vperm. But this requires the loaded constant not be used elsewhere (unlikely, but possible), or if it is, that all such uses are also xxlnor-vperm, so dataflow analysis for reached uses is required. Not completely trivial. Because it's a P8-only optimization, it's bit lower on the priority list.=