From c60d3bf2fa54298f2dcdea1cceda63e0c0b14ae3 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 22 Nov 2012 15:00:35 +0000 Subject: Fix sign of inexact zero results for ldbl-128ibm fmal. --- sysdeps/ieee754/ldbl-128ibm/s_fmal.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'sysdeps/ieee754/ldbl-128ibm/s_fmal.c') diff --git a/sysdeps/ieee754/ldbl-128ibm/s_fmal.c b/sysdeps/ieee754/ldbl-128ibm/s_fmal.c index a868b8d514..6706eb20ed 100644 --- a/sysdeps/ieee754/ldbl-128ibm/s_fmal.c +++ b/sysdeps/ieee754/ldbl-128ibm/s_fmal.c @@ -1,5 +1,5 @@ /* Compute x * y + z as ternary operation. - Copyright (C) 2011 Free Software Foundation, Inc. + Copyright (C) 2011-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by David Flaherty . @@ -29,6 +29,12 @@ __fmal (long double x, long double y, long double z) if ((finite ((double)x) && finite ((double)y)) && isinf ((double)z)) return (z); + /* If z is zero and x are y are nonzero, compute the result + as x * y to avoid the wrong sign of a zero result if x * y + underflows to 0. */ + if (z == 0 && x != 0 && y != 0) + return x * y; + return (x * y) + z; } #ifdef IS_IN_libm -- cgit 1.4.1