From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18532 invoked by alias); 12 Apr 2011 14:51:51 -0000 Received: (qmail 18522 invoked by uid 22791); 12 Apr 2011 14:51:49 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 12 Apr 2011 14:51:45 +0000 Received: (qmail 11367 invoked from network); 12 Apr 2011 14:51:44 -0000 Received: from unknown (HELO localhost) (froydnj@127.0.0.2) by mail.codesourcery.com with ESMTPA; 12 Apr 2011 14:51:44 -0000 Date: Tue, 12 Apr 2011 14:51:00 -0000 From: Nathan Froyd To: Richard Guenther Cc: gcc-patches@gcc.gnu.org Subject: Re: [PATCH] add statistics counting to postreload, copy-rename, and math-opts Message-ID: <20110412145143.GH23480@codesourcery.com> References: <20110412141626.GF23480@codesourcery.com> <20110412143205.GG23480@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-IsSubscribed: yes 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: 2011-04/txt/msg00895.txt.bz2 On Tue, Apr 12, 2011 at 04:37:42PM +0200, Richard Guenther wrote: > On Tue, Apr 12, 2011 at 4:32 PM, Nathan Froyd wrote: > > Thanks.  I may go twiddle that patch to do something similar to mine and > > submit that.  Do you use your patch for checking that the same set of > > optimizations get performed, then?  I'm interested in using the > > statistics for identifying passes that don't buy us much across a wide > > variety of codebases.  (Suggestions for suitable ones welcome!) > > Yes, I used it exactly for that. And also to verify that passes don't > do anything if replicated (well, for those that shouldn't at least). > > Don't expect any low-hanging fruit though ;) I catched all of it already. > > Candidates are obviously SPEC and GCC itself. I also use tramp3d > of course. That said, even if a pass does nearly nothing we often > have testcases that need it ... True, but maybe those testcases should be adjusted--per-pass flags, rather than blindly assuming -O2 includes them. And it's not clear to me that the statistics_counter_event infrastructure really helps catching do-nothing passes, since it doesn't record stats that increment by zero... -Nathan