From owner-freebsd-numerics@FreeBSD.ORG Fri Aug 9 19:45:39 2013 Return-Path: Delivered-To: freebsd-numerics@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 2225DBE0 for ; Fri, 9 Aug 2013 19:45:39 +0000 (UTC) (envelope-from Paul.Zimmermann@loria.fr) Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 885252DED for ; Fri, 9 Aug 2013 19:45:37 +0000 (UTC) X-IronPort-AV: E=Sophos;i="4.89,848,1367964000"; d="scan'208";a="28955005" Received: from tarte.loria.fr ([152.81.15.145]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/AES256-SHA; 09 Aug 2013 21:44:25 +0200 Received: from zimmerma by tarte.loria.fr with local (Exim 4.76) (envelope-from ) id 1V7sbp-0008Q6-MC for freebsd-numerics@freebsd.org; Fri, 09 Aug 2013 21:44:25 +0200 From: Zimmermann Paul Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=utf-8 To: freebsd-numerics@freebsd.org Subject: help requested with long double issue on 32-bit FreeBSD Message-Id: Sender: Zimmermann Paul Date: Fri, 09 Aug 2013 21:44:25 +0200 X-BeenThere: freebsd-numerics@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Discussions of high quality implementation of libm functions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Aug 2013 19:45:39 -0000 Hi, [this mail was sent on the MPFR list, but Steve Kargl suggested to post it also here] we need help to investigate an error we get with the development version of MPFR on i686-freebsd. The error occurs on the hydra.nixos.org continuous integration platform. Unfortunately we don't have direct access to the corresponding computer, thus isolating the issue is not easy. The error we get can be seen at http://hydra.nixos.org/build/5666171/log/raw. Starting from the long double value in 3, and subtracting e=0.25, we get the long double value in 4, which is obviously wrong in the last bits: 3: d=2.632048527199790448306230411512629530e-01 4: d=1.320485271997904469509776959057489876e-02 ^^^^^^^^^^^^^^^^^^^^ We believe this is a compiler bug (GCC 4.2.1 was used in this test). If you have access to a 32-bit computer under FreeBSD, please could you try to compile the development version and run the "tset_ld" test, after doing export GMP_CHECK_RANDOMIZE=1376689137? If you can reproduce the error, please tell Vincent Lefèvre and myself (Vincent.Lefevre at ens-lyon.fr and Paul.Zimmermann at inria.fr); we'll help you to isolate the problem (e.g., trying different optimization levels). If you can't reproduce (on a 32-bit FreeBSD machine), please tell us too; this might indicate the bug was fixed in a later gcc version. Thank you in advance, Paul Zimmermann