From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17400 invoked by alias); 22 Oct 2013 20:27:41 -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 17363 invoked by uid 48); 22 Oct 2013 20:27:38 -0000 From: "glisse at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/58806] New attribute for functions that access memory only through their arguments Date: Tue, 22 Oct 2013 20:27:00 -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-Version: 4.9.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: glisse at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created 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: 2013-10/txt/msg01634.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58806 --- Comment #5 from Marc Glisse --- Created attachment 31074 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31074&action=edit experimental patch This optimizes the testcase in comment #0 if I mark g with the attribute "no_global_write" and use some way of marking g's argument as EAF_DIRECT. Maybe it would be easier to have the no_global_write attribute (possibly with a different name) imply EAF_DIRECT on the arguments, as it gets tricky trying to see what we may alias by following an arbitrary chain starting at a given pointer.