From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26781 invoked by alias); 3 Jun 2009 09:55:51 -0000 Received: (qmail 26771 invoked by uid 22791); 3 Jun 2009 09:55:50 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,SPF_FAIL X-Spam-Check-By: sourceware.org Received: from mx20.gnu.org (HELO mx20.gnu.org) (199.232.41.8) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 03 Jun 2009 09:55:45 +0000 Received: from mail.codesourcery.com ([65.74.133.4]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MBnCA-0007RJ-Ui for gcc@gcc.gnu.org; Wed, 03 Jun 2009 05:55:43 -0400 Received: (qmail 13757 invoked from network); 3 Jun 2009 09:55:40 -0000 Received: from unknown (HELO rex.config) (julian@127.0.0.2) by mail.codesourcery.com with ESMTPA; 3 Jun 2009 09:55:40 -0000 Date: Wed, 03 Jun 2009 09:55:00 -0000 From: Julian Brown To: Michael Hope Cc: gcc@gcc.gnu.org Subject: Re: Using a umulhisi3 Message-ID: <20090603105538.3d340a7c@rex.config> In-Reply-To: <31d002d40906030239m3e6708b1xd89105c19105c1ab@mail.gmail.com> References: <31d002d40906030239m3e6708b1xd89105c19105c1ab@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Detected-Operating-System: by mx20.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) 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: 2009-06/txt/msg00035.txt.bz2 On Wed, 3 Jun 2009 21:39:34 +1200 Michael Hope wrote: > How does the combine stage work? It looks like it could get multiple > potential matches for a set of RTLs. Does it use some type of costing > function to pick between them? Can I tell combine that a umulhisi3 is > cheaper than a mulsi3? You could try defining TARGET_RTX_COSTS, if you haven't already. Julian