From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10543 invoked by alias); 4 Jul 2011 14:22:11 -0000 Received: (qmail 10525 invoked by uid 22791); 4 Jul 2011 14:22:09 -0000 X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW X-Spam-Check-By: sourceware.org Received: from mail-ww0-f41.google.com (HELO mail-ww0-f41.google.com) (74.125.82.41) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 04 Jul 2011 14:21:52 +0000 Received: by wwi14 with SMTP id 14so1525317wwi.2 for ; Mon, 04 Jul 2011 07:21:51 -0700 (PDT) MIME-Version: 1.0 Received: by 10.227.55.69 with SMTP id t5mr5271225wbg.94.1309789310955; Mon, 04 Jul 2011 07:21:50 -0700 (PDT) Received: by 10.227.36.212 with HTTP; Mon, 4 Jul 2011 07:21:50 -0700 (PDT) In-Reply-To: <1309444782.26980.52.camel@oc2474580526.ibm.com> References: <1309444782.26980.52.camel@oc2474580526.ibm.com> Date: Mon, 04 Jul 2011 14:22:00 -0000 Message-ID: Subject: Re: [PATCH] Address lowering [1/3] Main patch From: Richard Guenther To: "William J. Schmidt" Cc: gcc-patches@gcc.gnu.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-07/txt/msg00187.txt.bz2 On Thu, Jun 30, 2011 at 4:39 PM, William J. Schmidt wrote: > This is the first of three patches related to lowering addressing > expressions to MEM_REFs and TARGET_MEM_REFs in late gimple. =A0This patch > contains the new pass together with supporting changes in existing > modules. =A0The second patch contains an independent change to the RTL > forward propagator to keep it from undoing an optimization made in the > first patch. =A0The third patch contains new test cases and changes to > existing test cases. > > Although I've broken it up into three patches to make the review easier, > it would be best to commit at least the first and third together to > avoid regressions. =A0The second can stand alone. > > I've done regression tests on powerpc64 and x86_64, and have asked > Andreas Krebbel to test against the IBM z (390) platform. =A0I've done > performance regression testing on powerpc64. =A0The only performance > regression of note is the 2% degradation to 188.ammp due to loss of > field disambiguation information. =A0As discussed in another thread, > fixing this introduces more complexity than it's worth. Are there also performance improvements? What about code size? I tried to get an understanding to what kind of optimizations this patch produces based on the test of testcases you added, but I have a hard time here. Can you outline some please? I still do not like the implementation of yet another CSE machinery given that we already have two. I think most of the need for CSE comes from the use of the affine combination framework and force_gimple_operand. In fact I'd be interested to see cases that are optimized that could not be handled by a combine-like pattern matcher? Thanks, Richard.