From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11776 invoked by alias); 20 Mar 2012 20:06:53 -0000 Received: (qmail 11762 invoked by uid 22791); 20 Mar 2012 20:06:52 -0000 X-SWARE-Spam-Status: No, hits=-2.3 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-gy0-f175.google.com (HELO mail-gy0-f175.google.com) (209.85.160.175) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 20 Mar 2012 20:06:39 +0000 Received: by ghbz2 with SMTP id z2so493744ghb.20 for ; Tue, 20 Mar 2012 13:06:38 -0700 (PDT) MIME-Version: 1.0 Received: by 10.236.103.226 with SMTP id f62mr1430836yhg.0.1332273998345; Tue, 20 Mar 2012 13:06:38 -0700 (PDT) Received: by 10.100.88.7 with HTTP; Tue, 20 Mar 2012 13:06:38 -0700 (PDT) In-Reply-To: <4F68E062.5040202@gjlay.de> References: <4F5A4FFE.9000203@gjlay.de> <4F68E062.5040202@gjlay.de> Date: Tue, 20 Mar 2012 20:06:00 -0000 Message-ID: Subject: Re: [Patch,AVR]: Hack around PR rtl-optimization/52543, Take #2 From: Steven Bosscher To: Georg-Johann Lay Cc: gcc-patches@gcc.gnu.org, Denis Chertykov , Eric Weddington Content-Type: text/plain; charset=ISO-8859-1 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: 2012-03/txt/msg01389.txt.bz2 On Tue, Mar 20, 2012 at 8:54 PM, Georg-Johann Lay wrote: > Dropping the first patch which does not work because at expand-time there > must not be pre-/post-modify addressing :-( Have you tried to fix that, instead? Or at least ask around a bit to see what people would think about that idea? The reasons why things are the way they are, may not be applicable anymore. For example, perhaps the only reason for not having pre-/post-modify addressing modes earlier is that the old "flow" dataflow frame work didn't handle them. And it doesn't seem to be so black-and-white: The very pass you ran into problems with first, cprop, does handle pre-/post-modify addresses in local cprop. Some other passes simply take the conservative path and drop pre-/post-modify (like CSE, which doesn't record values from them). It may be a relatively small job to make everything accept them, and you may be something that's also helpful for other targets. Ciao! Steven