From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14723 invoked by alias); 23 Apr 2012 05:35:24 -0000 Received: (qmail 14663 invoked by uid 22791); 23 Apr 2012 05:35:23 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED,TW_DX 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; Mon, 23 Apr 2012 05:35:11 +0000 From: "xinliangli at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/53081] memcpy/memset loop recognition Date: Mon, 23 Apr 2012 05:35:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: xinliangli at gmail dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: 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: 2012-04/txt/msg01884.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53081 --- Comment #4 from davidxl 2012-04-23 05:34:55 UTC --- (In reply to comment #2) > I should mention I made one patch before based on the vectorizer code which did > detection of at least memset; it was while I was an intern at Apple. I posted > it and there was some review. And a few years back there was a paper at the > GCC summit about it and expanding it to memcpy. I don't know what happened to > that code though. Some simple analysis using scev to identify loads and stores with linear address should be good enough. LLVM's version also tries to merge smaller memsets into a larger one.