From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7740 invoked by alias); 21 Mar 2006 16:57:34 -0000 Received: (qmail 7695 invoked by alias); 21 Mar 2006 16:57:31 -0000 Date: Tue, 21 Mar 2006 16:57:00 -0000 Message-ID: <20060321165731.7694.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/18046] Missed jump threading optimization In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "dberlin at dberlin dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2006-03/txt/msg02088.txt.bz2 List-Id: ------- Comment #11 from dberlin at gcc dot gnu dot org 2006-03-21 16:57 ------- Subject: Re: Missed jump threading optimization On Tue, 2006-03-21 at 15:57 +0000, law at redhat dot com wrote: > > ------- Comment #9 from law at redhat dot com 2006-03-21 15:57 ------- > We've got zero chance of threading the jump in this case until the > partially redundant load from "i" is removed. > > Daniel -- there's a pretty obvious redundant load from the global > variable "i" in this testcase. I haven't investigated why PRE > is missing this obvious redundancy. It doesn't deal with loads from global variables because we need to place a value number on each "instance" that occurs in the program, but can't easily because they are all shared. I will get to it eventually. > > Jeff > > -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18046