From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6308 invoked by alias); 24 Oct 2006 14:23:43 -0000 Received: (qmail 6265 invoked by uid 48); 24 Oct 2006 14:23:35 -0000 Date: Tue, 24 Oct 2006 14:23:00 -0000 Message-ID: <20061024142335.6264.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/23855] loop header should also be pulled out of the inner loop too In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "dberlin at gcc dot gnu 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: 2006-10/txt/msg02101.txt.bz2 List-Id: ------- Comment #22 from dberlin at gcc dot gnu dot org 2006-10-24 14:23 ------- (In reply to comment #19) > So it is indeed chicken and egg ;) load-PRE does not PRE the loads if the loop > is not in do-while form, and we won't hoist the loop header copies until the > loads are PREd. As to comment #13, if we are able to "clean" the two innermost > loops > of a nest that is already a good improvement. Though from all the experiments > it looks like it is advisable to write do-while loops with hoisted loop header > copies manually rather than for loops. > So the PRE fixes i've got should help here, i think. Maybe not. :) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23855