From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 91281 invoked by alias); 3 Mar 2015 16:22:33 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 91178 invoked by uid 48); 3 Mar 2015 16:22:29 -0000 From: "wschmidt at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug testsuite/63175] [4.9/5 regression] FAIL: gcc.dg/vect/costmodel/ppc/costmodel-bb-slp-9a.c scan-tree-dump-times slp2" basic block vectorized using SLP" 1 Date: Tue, 03 Mar 2015 16:22:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: testsuite X-Bugzilla-Version: 4.9.1 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: wschmidt at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.9.3 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2015-03/txt/msg00337.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63175 --- Comment #29 from Bill Schmidt --- (In reply to Richard Biener from comment #26) > it makes sense. Note that we seem to prefer optimized re-alignment loads > over misaligned loads (even if double-word aligned) - the vectorizer is not > set > up to decide that based on costs (the misaligned load would cost 2 while > the optimized re-aligned load costs 6 - two aligned loads (2), one vector > stmt > for mask compute (1) and one permute (3)). My pending patch deals with this by having POWER8 pretend that it doesn't have a re-alignment load capability, enabling misaligned loads/stores, and setting the costs to reasonable values.