From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28987 invoked by alias); 18 Jul 2012 13:25:44 -0000 Received: (qmail 28968 invoked by uid 22791); 18 Jul 2012 13:25:41 -0000 X-SWARE-Spam-Status: No, hits=-5.0 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from e39.co.us.ibm.com (HELO e39.co.us.ibm.com) (32.97.110.160) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 18 Jul 2012 13:25:28 +0000 Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 Jul 2012 07:25:26 -0600 Received: from d03dlp02.boulder.ibm.com (9.17.202.178) by e39.co.us.ibm.com (192.168.1.139) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Wed, 18 Jul 2012 07:25:24 -0600 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id BD4C43E4004E for ; Wed, 18 Jul 2012 13:25:21 +0000 (WET) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q6IDOoMj146998 for ; Wed, 18 Jul 2012 07:24:52 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q6IDOlQV000374 for ; Wed, 18 Jul 2012 07:24:47 -0600 Received: from [9.10.86.212] (9-10-86-212.rchland.ibm.com [9.10.86.212]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q6IDOkE5000309; Wed, 18 Jul 2012 07:24:46 -0600 Subject: Re: [PATCH] Add flag to control straight-line strength reduction From: "William J. Schmidt" To: Richard Guenther Cc: Steven Bosscher , gcc-patches@gcc.gnu.org, bergner@vnet.ibm.com In-Reply-To: References: <1342538095.3470.59.camel@gnopaine> Content-Type: text/plain; charset="UTF-8" Date: Wed, 18 Jul 2012 13:25:00 -0000 Message-ID: <1342617885.4590.2.camel@oc2474580526.ibm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12071813-4242-0000-0000-0000025DC61B Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2012-07/txt/msg00818.txt.bz2 On Wed, 2012-07-18 at 11:01 +0200, Richard Guenther wrote: > On Wed, 18 Jul 2012, Steven Bosscher wrote: > > > On Wed, Jul 18, 2012 at 9:59 AM, Richard Guenther wrote: > > > On Tue, 17 Jul 2012, William J. Schmidt wrote: > > > > > >> I overlooked adding a pass-control flag for strength reduction, added > > >> here. I named it -ftree-slsr for consistency with other -ftree- flags, > > >> but could change it to -fgimple-slsr if you prefer that for a pass named > > >> gimple-ssa-... > > >> > > >> Bootstrapped and tested on powerpc-unknown-linux-gnu with no new > > >> regressions. Ok for trunk? > > > > > > The switch needs documentation in doc/invoke.texi. Other than that > > > it's fine to stick with -ftree-..., even that exposes details to our > > > users that are not necessary (RTL passes didn't have -frtl-... either). > > > So in the end, why not re-use -fstrength-reduce that is already available > > > (but stubbed out)? > > > > In the past, -fstrength-reduce applied to loop strength reduction in > > loop.c. I don't think it should be re-used for a completely different > > code transformation. > > Ok. I suppose -ftree-slsr is ok then. It turns out I was looking at a very old copy of the manual, and the -ftree... stuff is not as prevalent now as it once was. I'll just go with -fslsr to be consistent with -fgcse, -fipa-sra, etc. Thanks for the pointer to doc/invoke.texi -- it appears I also failed to document -fhoist-adjacent-loads, so I will go ahead and do that as well. Thanks! Bill > > Thanks, > Richard. >