From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13344 invoked by alias); 28 Aug 2008 08:47:06 -0000 Received: (qmail 12246 invoked by alias); 28 Aug 2008 08:45:46 -0000 Date: Thu, 28 Aug 2008 08:47:00 -0000 Message-ID: <20080828084546.12245.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/37242] missed FRE opportunity because of signedness of addition In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rguenther at suse dot de" 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: 2008-08/txt/msg02219.txt.bz2 ------- Comment #16 from rguenther at suse dot de 2008-08-28 08:45 ------- Subject: Re: missed FRE opportunity because of signedness of addition On Thu, 28 Aug 2008, bonzini at gnu dot org wrote: > ------- Comment #15 from bonzini at gnu dot org 2008-08-28 08:42 ------- > I think that PRE does not try to simplify expressions that it inserts. Correct. PRE does minimal expression simplification during PHI translation, but that's it. Note that gimple expressions itself never simplify apart from constant folding, the simplify_*_expression routines in SCCVN instead combine multiple expressions. Is the optimization the second PRE run does a full redundancy removal or a new partial redundancy? Richard. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37242