From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25625 invoked by alias); 13 May 2003 00:48:10 -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 25582 invoked from network); 13 May 2003 00:48:10 -0000 Received: from unknown (HELO mail-out2.apple.com) (17.254.0.51) by sources.redhat.com with SMTP; 13 May 2003 00:48:10 -0000 Received: from mailgate2.apple.com (A17-129-100-225.apple.com [17.129.100.225]) by mail-out2.apple.com (8.12.9/8.12.9) with ESMTP id h4D0m9nB021219 for ; Mon, 12 May 2003 17:48:09 -0700 (PDT) Received: from scv3.apple.com (scv3.apple.com) by mailgate2.apple.com (Content Technologies SMTPRS 4.2.1) with ESMTP id ; Mon, 12 May 2003 17:48:09 -0700 Received: from apple.com (johada5.apple.com [17.201.20.185]) by scv3.apple.com (8.12.9/8.12.9) with ESMTP id h4D0m8RM009183; Mon, 12 May 2003 17:48:08 -0700 (PDT) Date: Tue, 13 May 2003 00:48:00 -0000 Subject: Re: Dead-code elimination can't remove string copy insns? Content-Type: text/plain; charset=US-ASCII; format=flowed Mime-Version: 1.0 (Apple Message framework v551) Cc: Dale Johannesen , gcc@gcc.gnu.org To: Zack Weinberg From: Dale Johannesen In-Reply-To: <87addrpu7r.fsf@egil.codesourcery.com> Message-Id: <731C93BE-84DC-11D7-BAEF-000393D76DAA@apple.com> Content-Transfer-Encoding: 7bit X-SW-Source: 2003-05/txt/msg01260.txt.bz2 On Monday, May 12, 2003, at 05:26 PM, Zack Weinberg wrote: > Why can't anything delete these insns? I'm guessing it has something > to do with the BLKmode memory access, but the alias information should > be sufficient to see that the memory region being written into is on > the stack, and unused past this insn, hence the store is dead and can > be deleted. Can it tell the region's address hasn't been taken and stored somewhere? > Full dumps on request. The above snippets are from the .life dump. > The input file is gcc.dg/const-elim-1.c.