From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5849 invoked by alias); 29 Sep 2011 14:00:44 -0000 Received: (qmail 5838 invoked by uid 22791); 29 Sep 2011 14:00:42 -0000 X-SWARE-Spam-Status: No, hits=-1.3 required=5.0 tests=AWL,BAYES_00,RCVD_NUMERIC_HELO,RP_MATCHES_RCVD,SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from lo.gmane.org (HELO lo.gmane.org) (80.91.229.12) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 29 Sep 2011 14:00:23 +0000 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1R9H9x-0005Fd-Ex for gcc@gcc.gnu.org; Thu, 29 Sep 2011 16:00:21 +0200 Received: from 193.128.72.68 ([193.128.72.68]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 29 Sep 2011 16:00:21 +0200 Received: from paulo by 193.128.72.68 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 29 Sep 2011 16:00:21 +0200 To: gcc@gcc.gnu.org From: paulo@matos-sorge.com (Paulo J. Matos) Subject: Re: missing conditional propagation in cprop.c pass Date: Thu, 29 Sep 2011 15:26:00 -0000 Message-ID: <86wrcra1p9.fsf@pm18pc01.europe.root.pri> References: Mime-Version: 1.0 Content-Type: text/plain User-Agent: Gnus/5.110018 (No Gnus v0.18) Emacs/23.2 (gnu/linux) X-IsSubscribed: yes Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2011-09/txt/msg00366.txt.bz2 "Amker.Cheng" writes: > (insn 882 881 883 96 (set (reg:CC 24 cc) > (compare:CC (reg:SI 684 [ default_num_contexts ]) > (const_int 0 [0]))) core_main.c:265 211 {*arm_cmpsi_insn} > (nil)) > > > The insn49 should be propagated with conditional const from insn882 > and jump_insn883, optimized into "r291<-0" as following code, then let > pre do redundancy elimination work. Unless there's something arch specific related to arm, insn 882 is a compare, which won't change r684. Why do you think 0 should propagated to r291 if r684 is not zero? Cheers, -- PMatos