/* Test for NaN that does not need libm.
- Copyright (C) 2007 Free Software Foundation, Inc.
+ Copyright (C) 2007-2008 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#if HAVE_ISNANL_IN_LIBC
/* Get declaration of isnan macro or (older) isnanl function. */
# include <math.h>
-# ifdef isnan
+# if __GNUC__ >= 4
+ /* GCC 4.0 and newer provides three built-ins for isnan. */
+# undef isnanl
+# define isnanl(x) __builtin_isnanl ((long double)(x))
+# elif defined isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
# endif