From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32588 invoked by alias); 18 Dec 2014 03:02:49 -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 32528 invoked by uid 48); 18 Dec 2014 03:02:44 -0000 From: "amker at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/58623] lack of ldp/stp optimization Date: Thu, 18 Dec 2014 03:02:00 -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: 4.9.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: amker at gcc dot gnu.org X-Bugzilla-Status: RESOLVED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: amker 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: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-12/txt/msg02061.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58623 --- Comment #7 from amker at gcc dot gnu.org --- Hi Evandro, There is specific PR for this issue. But as we know, fwprop often corrupts optimizations on address expression, for below example: add rb, r1, r2 ldr rx, [rb] add rb, rb, #4 It's transformed into below by fwprop: add rb, r1, r2 ldr rx, [r1, r2] add rb, rb, #4 This corrupts post-increment opportunity. Though in different form, it's actually same issue as in ldp/stp. I think https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44883 describes the problem in some manner, and there might be other PR about it too.