-# isnanl.m4 serial 5
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# isnanl.m4 serial 6
+dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
[gl_cv_func_isnanl_no_libm],
[
AC_TRY_LINK([#include <math.h>
- #ifdef isnan
+ #if __GNUC__ >= 4
+ # undef isnanl
+ # define isnanl(x) __builtin_isnanl ((long double)(x))
+ #elif defined isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_TRY_LINK([#include <math.h>
- #ifdef isnan
+ #if __GNUC__ >= 4
+ # undef isnanl
+ # define isnanl(x) __builtin_isnanl ((long double)(x))
+ #elif defined isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif
dnl Test whether isnanl() recognizes all numbers which are neither finite nor
dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
+dnl Also, the GCC >= 4.0 built-in __builtin_isnanl does not pass the tests
+dnl - for pseudo-denormals on i686 and x86_64,
+dnl - for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
AC_DEFUN([gl_FUNC_ISNANL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
#include <float.h>
#include <limits.h>
#include <math.h>
-#ifdef isnan
+#if __GNUC__ >= 4
+# undef isnanl
+# define isnanl(x) __builtin_isnanl ((long double)(x))
+#elif defined isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif