From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11395 invoked by alias); 16 Jun 2015 12:19:19 -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 11379 invoked by uid 89); 16 Jun 2015 12:19:18 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 16 Jun 2015 12:19:17 +0000 Received: from nat-ies.mentorg.com ([192.94.31.2] helo=SVR-IES-FEM-01.mgc.mentorg.com) by relay1.mentorg.com with esmtp id 1Z4ppg-0007Vs-Uq from joseph_myers@mentor.com ; Tue, 16 Jun 2015 05:19:13 -0700 Received: from digraph.polyomino.org.uk (137.202.0.76) by SVR-IES-FEM-01.mgc.mentorg.com (137.202.0.104) with Microsoft SMTP Server id 14.3.224.2; Tue, 16 Jun 2015 13:19:11 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.82) (envelope-from ) id 1Z4ppd-0002Ro-QZ; Tue, 16 Jun 2015 12:19:09 +0000 Date: Tue, 16 Jun 2015 12:26:00 -0000 From: Joseph Myers To: "Maciej W. Rozycki" CC: Steve Ellcey , Richard Sandiford , , Catherine Moore , Matthew Fortune Subject: Re: [Patch, MIPS] Enable fp-contract on MIPS and update -mfused-madd In-Reply-To: Message-ID: References: <4c25620c-546c-40ae-b330-3652fe25f791@BAMAIL02.ba.imgtec.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-SW-Source: 2015-06/txt/msg01115.txt.bz2 On Tue, 16 Jun 2015, Maciej W. Rozycki wrote: > This makes me wonder however what the point has been to specify a strict > particular semantics for the copy, negate, abs, copySign operations with > respect to the sign bit of qNaN data where any other operation can then > change the bit in a random fashion. Do you happen to know what the > rationale and any possible use cases considered have been? I don't know. > Furthermore these checks were deliberately introduced by Richard with his > proposal here > and agreed upon in the discussion even before IEEE Std 754-2008 has been > made. Are you suggesting that the arguments used there, that have led to > the current arrangement, no longer stand and consequently the HONOR_NANS > checks introduced are now best dropped? Only the checks for abs and neg patterns are necessary, not those for fused operations. -- Joseph S. Myers joseph@codesourcery.com