Improve the accuracy of tgamma (BZ #26983)

[thirdparty/glibc.git] / math / w_atanh_compat.c

/* Copyright (C) 2011-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <math.h>
#include <math_private.h>
#include <math-svid-compat.h>
#include <libm-alias-double.h>


#if LIBM_SVID_COMPAT
/* wrapper atanh */
double
__atanh (double x)
{
  if (__builtin_expect (isgreaterequal (fabs (x), 1.0), 0)
      && _LIB_VERSION != _IEEE_)
    return __kernel_standard (x, x,
			      fabs (x) > 1.0
			      ? 30		/* atanh(|x|>1) */
			      : 31);		/* atanh(|x|==1) */

  return __ieee754_atanh (x);
}
libm_alias_double (__atanh, atanh)
#endif