GCC 4.0 or newer also has a built-in for isnan(double). This patch makes use of
it.
2008-01-26 Bruno Haible <[EMAIL PROTECTED]>
* m4/isnand.m4 (gl_FUNC_ISNAND_NO_LIBM): Test the GCC >= 4.0 built-in.
* lib/isnand.h (isnand): Use the GCC >= 4.0 built-in.
*** lib/isnand.h.orig 2008-01-26 15:34:00.000000000 +0100
--- lib/isnand.h 2008-01-26 15:33:42.000000000 +0100
***************
*** 17,23 ****
#if HAVE_ISNAND_IN_LIBC
/* Get declaration of isnan macro. */
# include <math.h>
! # ifdef isnan
# undef isnand
# define isnand(x) isnan ((double)(x))
# endif
--- 17,27 ----
#if HAVE_ISNAND_IN_LIBC
/* Get declaration of isnan macro. */
# include <math.h>
! # if __GNUC__ >= 4
! /* GCC 4.0 and newer provides three built-ins for isnan. */
! # undef isnand
! # define isnand(x) __builtin_isnan ((double)(x))
! # else
# undef isnand
# define isnand(x) isnan ((double)(x))
# endif
*** m4/isnand.m4.orig 2008-01-26 15:34:00.000000000 +0100
--- m4/isnand.m4 2008-01-26 15:32:13.000000000 +0100
***************
*** 1,4 ****
! # isnand.m4 serial 1
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,
--- 1,4 ----
! # isnand.m4 serial 2
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,
***************
*** 12,19 ****
[gl_cv_func_isnand_no_libm],
[
AC_TRY_LINK([#include <math.h>
double x;],
! [return isnan (x);],
[gl_cv_func_isnand_no_libm=yes],
[gl_cv_func_isnand_no_libm=no])
])
--- 12,26 ----
[gl_cv_func_isnand_no_libm],
[
AC_TRY_LINK([#include <math.h>
+ #if __GNUC__ >= 4
+ # undef isnand
+ # define isnand(x) __builtin_isnan ((double)(x))
+ #else
+ # undef isnand
+ # define isnand(x) isnan ((double)(x))
+ #endif
double x;],
! [return isnand (x);],
[gl_cv_func_isnand_no_libm=yes],
[gl_cv_func_isnand_no_libm=no])
])
