From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 764 invoked by alias); 9 Mar 2018 18:19:10 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 677 invoked by uid 89); 9 Mar 2018 18:19:09 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.2 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,SPF_NEUTRAL autolearn=no version=3.3.2 spammy=claim, millions X-HELO: popelka.ms.mff.cuni.cz Date: Fri, 09 Mar 2018 18:19:00 -0000 From: =?utf-8?B?T25kxZllaiBCw61sa2E=?= To: Siddhesh Poyarekar Cc: Wilco Dijkstra , "libc-alpha@sourceware.org" , nd Subject: Re: [PATCH 2/6] Remove slow paths from sin/cos Message-ID: <20180309181902.GA26430@domone> References: <8065ca77-ec8f-9925-7e9c-52266cd1e4c6@gotplt.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8065ca77-ec8f-9925-7e9c-52266cd1e4c6@gotplt.org> User-Agent: Mutt/1.5.20 (2009-06-14) X-SW-Source: 2018-03/txt/msg00249.txt.bz2 On Fri, Mar 09, 2018 at 09:47:09PM +0530, Siddhesh Poyarekar wrote: > On Friday 09 March 2018 09:16 PM, Wilco Dijkstra wrote: > > This patch removes 2nd of the 3 range reduction cases and defer to the final one. > > Input values above 2^27 are extremely rare, so this case doesn't need to as be > > optimized as smaller inputs. > > Please elaborate on two more points: > > - The basis for your claim that values above 2^27 are extremely rare, > i.e. papers that you may have referred that conclude this and/or > applications you may have profiled > Main reason is that for these inputs accuracy doesn't make a sense. There is already millions bigger error caused by limited precision when rounding input to float.