From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25073 invoked by alias); 23 Nov 2008 13:09:22 -0000 Received: (qmail 18305 invoked by uid 48); 23 Nov 2008 13:07:55 -0000 Date: Sun, 23 Nov 2008 13:09:00 -0000 Message-ID: <20081123130755.18304.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/23286] missed fully redundant expression In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "steven 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: 2008-11/txt/msg01963.txt.bz2 ------- Comment #16 from steven at gcc dot gnu dot org 2008-11-23 13:07 ------- Created an attachment (id=16751) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16751&action=view) Proof-of-concept patch It is not terribly complicated to add hoisting to tree-ssa-pre.c. I have attached the result of roughly half a day of hacking. It is a proof-of-concept patch that demonstrates how hoisting could be added. It's not finished, tested, or even correct ;-) but it shows the general idea. For a "production-quality" version, one would have to make sure not to hoist expressions up too far (e.g. not further up than above the first block that generates the expression). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23286