From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15257 invoked by alias); 14 Jun 2012 18:39:21 -0000 Received: (qmail 15247 invoked by uid 22791); 14 Jun 2012 18:39:20 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 14 Jun 2012 18:39:08 +0000 From: "rth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/53533] [4.7/4.8 regression] vectorization causes loop unrolling test slowdown as measured by Adobe's C++Benchmark Date: Thu, 14 Jun 2012 18:39:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: rth at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: rth at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Status Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 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 X-SW-Source: 2012-06/txt/msg00947.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53533 Richard Henderson changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED --- Comment #16 from Richard Henderson 2012-06-14 18:38:30 UTC --- Dunno exactly. The pre-SSE4.1 emulation of PMULLD has been there since at least gcc 4.5. What's not present in *any* version so far are some proper rtx_costs for integer vector operations. So any questions the vectorizer might be asking about what transformations are profitable are currently being given bogus answers. I'm hoping just that will fix the regression, though I also plan to address some of the other algorithmic questions raised in this PR.