From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31040 invoked by alias); 16 Sep 2015 16:39:08 -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 31030 invoked by uid 89); 16 Sep 2015 16:39:07 -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; Wed, 16 Sep 2015 16:39:06 +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 1ZcFjb-0005R4-3N from joseph_myers@mentor.com ; Wed, 16 Sep 2015 09:39:03 -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; Wed, 16 Sep 2015 17:39:01 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.82) (envelope-from ) id 1ZcFjY-0005pX-17; Wed, 16 Sep 2015 16:39:00 +0000 Date: Wed, 16 Sep 2015 17:03:00 -0000 From: Joseph Myers To: Sujoy Saraswati CC: Richard Biener , GCC Patches Subject: Re: Fix 61441 In-Reply-To: Message-ID: References: User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-SW-Source: 2015-09/txt/msg01210.txt.bz2 On Wed, 16 Sep 2015, Sujoy Saraswati wrote: > > If -fsignaling-nans, then folding of expressions involving sNaNs should be > > disabled, outside of static initializers - such expressions should not get > > folded to return an sNaN (it's incorrect to fold sNaN + 1 to sNaN, for > > example). I think existing code may ensure that (the HONOR_SNANS check in > > const_binop, for example). > > Yes, with -fsignaling-nans, the const_binop will not fold since the > HONOR_SNANS check is there. However, elsewhere, like const_unop, the > code doesn't do this check. Which would be a bug in the const_unop code, or the functions it calls (for operations for which such a check is appropriate - as noted, abs and negation should be folded unconditionally). -- Joseph S. Myers joseph@codesourcery.com