From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27001 invoked by alias); 8 Jan 2010 11:53:07 -0000 Received: (qmail 26924 invoked by uid 48); 8 Jan 2010 11:52:55 -0000 Date: Fri, 08 Jan 2010 11:53:00 -0000 Message-ID: <20100108115255.26923.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/42646] Jump threading breaks canonical loop forms In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rguenth at gcc dot gnu dot org" Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2010-01/txt/msg00927.txt.bz2 ------- Comment #4 from rguenth at gcc dot gnu dot org 2010-01-08 11:52 ------- It just means that we shouldn't thread to the header but always to the latch block. Note that this restriction should probably be restricted to the threading before loop optimizations. Or the 1st jump threading should simply avoid to thread over backedges (equivalent to removing the 1st DOM pass - though there is interesting fallout regarding jump-threading / loop header copying pass ordering). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42646