From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16406 invoked by alias); 16 Dec 2002 21:13:58 -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 16398 invoked from network); 16 Dec 2002 21:13:57 -0000 Received: from unknown (HELO mx2.redhat.com) (12.150.115.133) by sources.redhat.com with SMTP; 16 Dec 2002 21:13:57 -0000 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.11.6/8.11.6) with ESMTP id gBGL94N26280; Mon, 16 Dec 2002 16:09:04 -0500 Received: from krusty.sfbay.redhat.com (krusty.sfbay.redhat.com [172.16.27.45]) by int-mx2.corp.redhat.com (8.11.6/8.11.6) with ESMTP id gBGLCsN25891; Mon, 16 Dec 2002 16:12:54 -0500 Received: (from rth@localhost) by krusty.sfbay.redhat.com (8.11.6/8.11.6) id gBGLCkK05839; Mon, 16 Dec 2002 21:12:46 GMT X-Authentication-Warning: krusty.sfbay.redhat.com: rth set sender to rth@redhat.com using -f Date: Mon, 16 Dec 2002 13:32:00 -0000 From: Richard Henderson To: Toon Moene Cc: gcc@gcc.gnu.org Subject: Re: possible gcse failure: not able to eliminate redundant loads Message-ID: <20021216211245.F4851@redhat.com> Mail-Followup-To: Richard Henderson , Toon Moene , gcc@gcc.gnu.org References: <20021213093054.GA29293@redhat.com> <3DFA4252.3060309@moene.indiv.nluug.nl> <20021216180441.C3953@redhat.com> <3DFE3FC1.9020802@moene.indiv.nluug.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <3DFE3FC1.9020802@moene.indiv.nluug.nl>; from toon@moene.indiv.nluug.nl on Mon, Dec 16, 2002 at 10:04:01PM +0100 X-SW-Source: 2002-12/txt/msg00929.txt.bz2 On Mon, Dec 16, 2002 at 10:04:01PM +0100, Toon Moene wrote: > BTW, I wasn't aware it's legal to dereference NULL C pointers. It isn't, of course. But that's the whole point. You've got code that says x = (condition ? *p : 0); i.e. the dereference is protected by a conditional. Thus we can't hoist the dereference past the conditional (and thence out of the loop that started this thread). r~