From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32563 invoked by alias); 31 Aug 2004 18:55:51 -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 32556 invoked from network); 31 Aug 2004 18:55:50 -0000 Received: from unknown (HELO bluesmobile.specifixinc.com) (64.220.152.98) by sourceware.org with SMTP; 31 Aug 2004 18:55:50 -0000 Received: from specifixinc.com (unknown [192.168.1.2]) by bluesmobile.specifixinc.com (Postfix) with ESMTP id 7A8541649A; Tue, 31 Aug 2004 11:55:50 -0700 (PDT) Message-ID: <4134C9B6.30201@specifixinc.com> Date: Tue, 31 Aug 2004 19:18:00 -0000 From: James E Wilson User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.6) Gecko/20040114 MIME-Version: 1.0 To: Zdenek Dvorak Cc: gcc@gcc.gnu.org Subject: Re: On -ftrapv vs. libcalls... References: <200408221254.28457.stevenb@suse.de> <20040831135711.GA19870@atrey.karlin.mff.cuni.cz> In-Reply-To: <20040831135711.GA19870@atrey.karlin.mff.cuni.cz> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2004-08/txt/msg01657.txt.bz2 Zdenek Dvorak wrote: > What I do not understand is why it is legal to turn the libcall back > into MULT. Because there is a REG_EQUAL note that claims the mulvdi3 result is exactly equivalent to an ordinary multiply. If it isn't exactly the same as an ordinary multiply, then the REG_EQUAL note should not be there. Or else the REG_EQUAL note should be changed to be accurate, but that would probably require creating a new RTL operator, e.g. multv. -- Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com