From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19910 invoked by alias); 21 Nov 2005 18:07:12 -0000 Received: (qmail 19476 invoked by uid 48); 21 Nov 2005 18:07:11 -0000 Date: Mon, 21 Nov 2005 18:07:00 -0000 Message-ID: <20051121180711.19475.qmail@sourceware.org> From: "jakub at redhat dot com" To: glibc-bugs@sources.redhat.com In-Reply-To: <20050428174956.887.uttamp@us.ibm.com> References: <20050428174956.887.uttamp@us.ibm.com> Reply-To: sourceware-bugzilla@sourceware.org Subject: [Bug math/887] Math library function "logb" and "nextafter" inconsistent X-Bugzilla-Reason: CC Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-owner@sourceware.org X-SW-Source: 2005-11/txt/msg00103.txt.bz2 List-Id: ------- Additional Comments From jakub at redhat dot com 2005-11-21 18:07 ------- The patch is definitely wrong. First of all, you haven't proven in any way with standard references that the current behaviour is incorrect. If that is a bug (I'm not aware of any part of the standard that would mandate that), then it would be a generic GCC problem on ppc32 with casts from int to double with FE_DOWNWARD rounding. As on ppc32 we can't assume a hw instruction for that, GCC on ppc32 computes the cast as ((double) (4503601774854144 + i)) - 4503601774854144.0 for int i. With FE_DOWNWARD rounding and i == 0, this results in -0.0. Working around this for two randomly picked functions when the same thing occurs in hundreds of other functions is certainly not the way to go. -- http://sourceware.org/bugzilla/show_bug.cgi?id=887 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is.