From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29319 invoked by alias); 27 Mar 2013 11:19:55 -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 29266 invoked by uid 48); 27 Mar 2013 11:19:49 -0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/54939] Very poor vectorization of loops with complex arithmetic Date: Wed, 27 Mar 2013 11:19:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Status Blocks AssignedTo 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 X-SW-Source: 2013-03/txt/msg01996.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54939 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED Blocks| |37021 AssignedTo|unassigned at gcc dot |rguenth at gcc dot gnu.org |gnu.org | --- Comment #5 from Richard Biener 2013-03-27 11:19:49 UTC --- Confirmed. GCC vectorizes this using hybrid SLP - it unrolls the loop once to be able to vectorize two minus and two adds resulting from the complex multiplication. The PR is kind-of a duplicate of PR37021 where also a reduction and a variable stride is involved. So fixing this bug is required to more efficiently vectorize PR37021. Note that even this bug has multiple issues that need to be tackled. I happen to work on them.