From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28327 invoked by alias); 13 Dec 2004 11:03:05 -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 27895 invoked from network); 13 Dec 2004 11:02:47 -0000 Received: from unknown (HELO cri.ensmp.fr) (193.48.171.195) by sourceware.org with SMTP; 13 Dec 2004 11:02:47 -0000 Received: from illkirch.cri.ensmp.fr (illkirch.cri.ensmp.fr [10.2.14.167]) by cri.ensmp.fr (8.11.2/8.11.2/mx-cri-CRI) with ESMTP id iBDB2hh26107; Mon, 13 Dec 2004 12:02:43 +0100 (MET) Received: from illkirch.cri.ensmp.fr (seb@illkirch [127.0.0.1]) by illkirch.cri.ensmp.fr (8.13.1/8.13.1/Debian-18) with ESMTP id iBDAvnBB003544 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Mon, 13 Dec 2004 11:57:49 +0100 Received: (from seb@localhost) by illkirch.cri.ensmp.fr (8.13.1/8.13.1/Submit) id iBDAvnkf003541; Mon, 13 Dec 2004 11:57:49 +0100 Date: Mon, 13 Dec 2004 11:03:00 -0000 From: Sebastian Pop To: Mostafa Hagog Cc: gcc@gcc.gnu.org Subject: Re: SMS improvements branch Message-ID: <20041213105749.GB2083@cri.ensmp.fr> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.6+20040722i X-SW-Source: 2004-12/txt/msg00445.txt.bz2 On Thu, Dec 09, 2004 at 09:45:41PM +0200, Mostafa Hagog wrote: > > 6. Port tree data dependency analysis routines to the RTL level > so we can have better dependancy. (Future, Beyond 4.1) Seems a reasonable alternative approach to the transmission of data dependence information from GIMPLE to the RTL level. However (the following is just a guess, I have no numbers ;-) at RTL level, a data dependence analyzer would obtain less precise information than at tree level, because the informations such as the dimensions of arrays are lost. There are solutions for each of the problems that could occur during the data dependence analysis at RTL level, and this is why I have said that it was just a guess. > II. SMS related work : > 1. Use of alias sets to remove memory dependencies. (DONE, for 4.1) > 2. Remove register anti-dependencies. (DONE, for 4.1) > 3. Add backtracking to the SMS. (DONE, for 4.1) > 4. Consider register pressure in SMS. (Beyond 4.1) > Sid-Ahmed-Ali Touati has pointed me to the following report by the author of the SMS algorithm, that shows some drawbacks of the SMS algorithm: http://www.hpl.hp.com/techreports/2002/HPL-2002-239.html but anyway, you're probably aware of this work. Sebastian