From patchwork Mon Jun 30 16:42:28 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Myers X-Patchwork-Id: 1820 Received: (qmail 11059 invoked by alias); 30 Jun 2014 16:42:38 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 11040 invoked by uid 89); 30 Jun 2014 16:42:36 -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 autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Date: Mon, 30 Jun 2014 16:42:28 +0000 From: "Joseph S. Myers" To: Subject: Fix ldbl-128 expm1l spurious underflow (bug 16539) Message-ID: MIME-Version: 1.0 This patch fixes spurious underflows from ldbl-128 expm1l, as reported in and exposed by the tests added for such a bug in the x86 / x86-64 version. The bug and fix are essentially the same, so no separate bug is filed in Bugzilla. Tested for mips64. 2014-06-30 Joseph Myers [BZ #16539] * sysdeps/ieee754/ldbl-128/s_expm1l.c: Include . (__expm1l): Return argument unchanged when small but not subnormal. diff --git a/sysdeps/ieee754/ldbl-128/s_expm1l.c b/sysdeps/ieee754/ldbl-128/s_expm1l.c index 1c12109..f708af5 100644 --- a/sysdeps/ieee754/ldbl-128/s_expm1l.c +++ b/sysdeps/ieee754/ldbl-128/s_expm1l.c @@ -54,6 +54,7 @@ #include +#include #include #include @@ -136,6 +137,10 @@ __expm1l (long double x) if (x < minarg) return (4.0/big - 1.0L); + /* Avoid internal underflow when result does not underflow. */ + if (fabsl (x) < 0x1p-113L && fabsl (x) >= LDBL_MIN) + return x; + /* Express x = ln 2 (k + remainder), remainder not exceeding 1/2. */ xx = C1 + C2; /* ln 2. */ px = __floorl (0.5 + x / xx);