From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 69758 invoked by alias); 10 Feb 2018 12:29:21 -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 69742 invoked by uid 89); 10 Feb 2018 12:29:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 spammy= X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sat, 10 Feb 2018 12:29:19 +0000 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AB668356DB; Sat, 10 Feb 2018 12:29:17 +0000 (UTC) Received: from redhat.com (ovpn-204-40.brq.redhat.com [10.40.204.40]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 48F865D98E; Sat, 10 Feb 2018 12:29:16 +0000 (UTC) Date: Sat, 10 Feb 2018 12:29:00 -0000 From: Marek Polacek To: Jakub Jelinek Cc: Richard Biener , Jeff Law , Wilco Dijkstra , gcc-patches@gcc.gnu.org Subject: Re: [PATCH] Improve pow (C, x) -> exp (log (C) * x) optimization (PR middle-end/84309) Message-ID: <20180210122913.GL2608@redhat.com> References: <20180209233738.GQ5867@tucnak> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180209233738.GQ5867@tucnak> User-Agent: Mutt/1.9.1 (2017-09-22) X-SW-Source: 2018-02/txt/msg00577.txt.bz2 On Sat, Feb 10, 2018 at 12:37:38AM +0100, Jakub Jelinek wrote: > Hi! > > Apparently the new pow(C,x) -> exp(log(C)*x) if C > 0 optimization > breaks some package (Marek should know which), as it has 7ulp error. > Generally one should be prepared for some errors with -ffast-math. I reduced it from "test-cachunker" in package casync. Marek