From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 69936 invoked by alias); 14 Aug 2017 12:31:54 -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 125733 invoked by uid 89); 14 Aug 2017 12:31:01 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS,URIBL_RED autolearn=ham version=3.3.2 spammy=H*c:HHHHH 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; Mon, 14 Aug 2017 12:30:33 +0000 Received: from nat-ies.mentorg.com ([192.94.31.2] helo=svr-ies-mbx-01.mgc.mentorg.com) by relay1.mentorg.com with esmtp id 1dhEVq-0001RI-Ns from joseph_myers@mentor.com ; Mon, 14 Aug 2017 05:30:30 -0700 Received: from digraph.polyomino.org.uk (137.202.0.87) by svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) with Microsoft SMTP Server (TLS) id 15.0.1263.5; Mon, 14 Aug 2017 13:30:27 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.86_2) (envelope-from ) id 1dhEVj-0002BR-Ln; Mon, 14 Aug 2017 12:30:23 +0000 Date: Mon, 14 Aug 2017 13:17:00 -0000 From: Joseph Myers To: =?ISO-8859-15?Q?Pekka_J=E4=E4skel=E4inen?= CC: Richard Biener , GCC Patches , =?ISO-8859-15?Q?Henry_Linjam=E4ki?= , Martin Jambor Subject: Re: [PATCH] -fftz-math: assume that denorms _must_ be flushed to zero optimizations In-Reply-To: Message-ID: References: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="-1152306461-1622384054-1502713823=:29224" X-ClientProxiedBy: svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) X-SW-Source: 2017-08/txt/msg00873.txt.bz2 ---1152306461-1622384054-1502713823=:29224 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Content-length: 675 On Mon, 14 Aug 2017, Pekka Jääskeläinen wrote: > Both the inputs and outputs must be flushed to zero in the HSAIL’s > ‘ftz’ semantics. Presumably this means that constant folding needs to know about those semantics, both for operations with a subnormal floating-point argument (whether or not the output is floating point, or floating point in the same format), and those with such a result? Can assignments copy subnormals without converting them to zero? Should comparisons flush input subnormals to zero before comparing? Should conversions e.g. from float to double convert a float subnormal input to zero? -- Joseph S. Myers joseph@codesourcery.com ---1152306461-1622384054-1502713823=:29224--