From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22597 invoked by alias); 30 Aug 2004 15:12:41 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 22528 invoked from network); 30 Aug 2004 15:12:40 -0000 Received: from unknown (HELO atrey.karlin.mff.cuni.cz) (195.113.31.123) by sourceware.org with SMTP; 30 Aug 2004 15:12:40 -0000 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 4018) id 7DA5C4B43A3; Mon, 30 Aug 2004 17:12:40 +0200 (CEST) Date: Mon, 30 Aug 2004 16:34:00 -0000 From: Jan Hubicka To: Steven Bosscher Cc: Giovanni Bajo , gcc@gcc.gnu.org Subject: Re: GCC 3.5 Status (2004-08-29) Message-ID: <20040830151240.GD22834@atrey.karlin.mff.cuni.cz> References: <4132641E.3030206@codesourcery.com> <200408300908.32374.stevenb@suse.de> <02df01c48e78$c1d50780$8f432597@bagio> <200408301217.06743.stevenb@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200408301217.06743.stevenb@suse.de> User-Agent: Mutt/1.5.6i X-SW-Source: 2004-08/txt/msg01497.txt.bz2 > On Monday 30 August 2004 12:04, Giovanni Bajo wrote: > > Thanks for the update. Do you think it is feasable to have a special > > version of DCE/CCP (or a special flag in them) so that they don't destroy > > user variables, to be used at -O0? > > We discussed that, yes. You could look into how CCP propagates > things like addresses and so on, and figure out other things that > cause us to lose the user's variable. > DCE is not a real problem. If CCP would just not turn so many > statements into dead code, it would work ;-) I think all we need is to avoid CCP on user variables so user can change their value and DCE killing whole statements so user can breakpoint. Perhaps we can even consider idea of passing down the NOPs for statements that have completely no effect. This should be embeddable into existing CCP/DCE code... perhaps ;) Honza > > Gr. > Steven >