From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7629 invoked by alias); 7 May 2007 08:39:00 -0000 Received: (qmail 7584 invoked by alias); 7 May 2007 08:38:50 -0000 Date: Mon, 07 May 2007 08:39:00 -0000 Message-ID: <20070507083850.7582.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360 In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rakdver at kam dot mff dot cuni dot cz" 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 X-SW-Source: 2007-05/txt/msg00559.txt.bz2 ------- Comment #5 from rakdver at kam dot mff dot cuni dot cz 2007-05-07 09:38 ------- Subject: Re: [4.2/4.3 Regression] Code size regression caused by fix to PR 31360 > (In reply to comment #2) > > > 1) Hoists a register containing 0 out of the loop > > The correct thing to do. > > > Not necessarily. Hoisting literal constants means that opportunities to simply > insns based on that constant are potentially lost. This could be prevented if invariant motion added equivalence notes; nevertheless, one could argue that such simplifications should have been performed before loop invariant motion (in cse). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31849