From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 44232 invoked by alias); 8 Apr 2015 07:38:21 -0000 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 Received: (qmail 44221 invoked by uid 89); 8 Apr 2015 07:38:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.3 required=5.0 tests=AWL,BAYES_50,KAM_LAZY_DOMAIN_SECURITY,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 X-HELO: mx2.suse.de Received: from cantor2.suse.de (HELO mx2.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (CAMELLIA256-SHA encrypted) ESMTPS; Wed, 08 Apr 2015 07:38:10 +0000 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 909EFAC24; Wed, 8 Apr 2015 07:38:07 +0000 (UTC) Date: Wed, 08 Apr 2015 07:38:00 -0000 From: Richard Biener To: "Gopalasubramanian, Ganesh" cc: Uros Bizjak , "gcc-patches@gcc.gnu.org" Subject: RE: [PATCH] Fix bdverN vector cost of cond_[not_]taken_branch_cost In-Reply-To: Message-ID: References: User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SW-Source: 2015-04/txt/msg00293.txt.bz2 On Wed, 8 Apr 2015, Gopalasubramanian, Ganesh wrote: > > I have added a person from AMD to comment on the decision. > > Otherwise, the patch looks OK, but please wait a couple of days for possible comments. > > Thank you Uros! > I am checking the changes with few tests and benchmarking them. > Please wait for a couple of days. Note that before the fixes for PR64909 the epilogue/prologue loops had very large costs associated due to a bug in the cost model implementation. After the fix their cost is reasonable but the cost of the extra jumps is way under-accounted for due to the numbers for cond_taken_branch_cost and cond_not_taken_branch_cost. The proposes match mitigates that somewhat. How did you arrive at the original cost model? Thanks, Richard. -- Richard Biener SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Jennifer Guild, Dilip Upmanyu, Graham Norton HRB 21284 (AG Nuernberg)