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# isnanf.m4 serial 18
dnl Copyright (C) 2007-2021 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.
dnl Check how to get or define isnanf().
AC_DEFUN([gl_FUNC_ISNANF],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
ISNANF_LIBM=
gl_HAVE_ISNANF_NO_LIBM
if test $gl_cv_func_isnanf_no_libm = no; then
gl_HAVE_ISNANF_IN_LIBM
if test $gl_cv_func_isnanf_in_libm = yes; then
ISNANF_LIBM=-lm
fi
fi
dnl The variable gl_func_isnanf set here is used by isnan.m4.
if test $gl_cv_func_isnanf_no_libm = yes \
|| test $gl_cv_func_isnanf_in_libm = yes; then
save_LIBS="$LIBS"
LIBS="$LIBS $ISNANF_LIBM"
gl_ISNANF_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_isnanf_works" in
*yes) gl_func_isnanf=yes ;;
*) gl_func_isnanf=no; ISNANF_LIBM= ;;
esac
else
gl_func_isnanf=no
fi
if test $gl_func_isnanf != yes; then
HAVE_ISNANF=0
fi
AC_SUBST([ISNANF_LIBM])
])
dnl Check how to get or define isnanf() without linking with libm.
AC_DEFUN([gl_FUNC_ISNANF_NO_LIBM],
[
gl_HAVE_ISNANF_NO_LIBM
if test $gl_cv_func_isnanf_no_libm = yes; then
gl_ISNANF_WORKS
fi
if test $gl_cv_func_isnanf_no_libm = yes \
&& { case "$gl_cv_func_isnanf_works" in
*yes) true;;
*) false;;
esac
}; then
gl_func_isnanf_no_libm=yes
AC_DEFINE([HAVE_ISNANF_IN_LIBC], [1],
[Define if the isnan(float) function is available in libc.])
else
gl_func_isnanf_no_libm=no
fi
])
dnl Prerequisites of replacement isnanf definition. It does not need -lm.
AC_DEFUN([gl_PREREQ_ISNANF],
[
gl_FLOAT_EXPONENT_LOCATION
])
dnl Test whether isnanf() can be used without libm.
AC_DEFUN([gl_HAVE_ISNANF_NO_LIBM],
[
AC_CACHE_CHECK([whether isnan(float) can be used without linking with libm],
[gl_cv_func_isnanf_no_libm],
[
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
#if (__GNUC__ >= 4) || (__clang_major__ >= 4)
# undef isnanf
# define isnanf(x) __builtin_isnan ((float)(x))
#elif defined isnan
# undef isnanf
# define isnanf(x) isnan ((float)(x))
#endif
float x;]],
[[return isnanf (x);]])],
[gl_cv_func_isnanf_no_libm=yes],
[gl_cv_func_isnanf_no_libm=no])
])
])
dnl Test whether isnanf() can be used with libm.
AC_DEFUN([gl_HAVE_ISNANF_IN_LIBM],
[
AC_CACHE_CHECK([whether isnan(float) can be used with libm],
[gl_cv_func_isnanf_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <math.h>
#if (__GNUC__ >= 4) || (__clang_major__ >= 4)
# undef isnanf
# define isnanf(x) __builtin_isnan ((float)(x))
#elif defined isnan
# undef isnanf
# define isnanf(x) isnan ((float)(x))
#endif
float x;]],
[[return isnanf (x);]])],
[gl_cv_func_isnanf_in_libm=yes],
[gl_cv_func_isnanf_in_libm=no])
LIBS="$save_LIBS"
])
])
dnl Test whether isnanf() rejects Infinity (this fails on Solaris 2.5.1),
dnl recognizes a NaN (this fails on IRIX 6.5 with cc), and recognizes a NaN
dnl with in-memory representation 0x7fbfffff (this fails on IRIX 6.5).
AC_DEFUN([gl_ISNANF_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_FLOAT_EXPONENT_LOCATION])
AC_CACHE_CHECK([whether isnan(float) works], [gl_cv_func_isnanf_works],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <math.h>
#if (__GNUC__ >= 4) || (__clang_major__ >= 4)
# undef isnanf
# define isnanf(x) __builtin_isnan ((float)(x))
#elif defined isnan
# undef isnanf
# define isnanf(x) isnan ((float)(x))
#endif
/* The Compaq (ex-DEC) C 6.4 compiler chokes on the expression 0.0 / 0.0. */
#ifdef __DECC
static float
NaN ()
{
static float zero = 0.0f;
return zero / zero;
}
#else
# define NaN() (0.0f / 0.0f)
#endif
#define NWORDS \
((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
typedef union { unsigned int word[NWORDS]; float value; } memory_float;
int main()
{
int result = 0;
if (isnanf (1.0f / 0.0f))
result |= 1;
if (!isnanf (NaN ()))
result |= 2;
#if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
/* The isnanf function should be immune against changes in the sign bit and
in the mantissa bits. The xor operation twiddles a bit that can only be
a sign bit or a mantissa bit. */
if (FLT_EXPBIT0_WORD == 0 && FLT_EXPBIT0_BIT > 0)
{
memory_float m;
m.value = NaN ();
/* Set the bits below the exponent to 01111...111. */
m.word[0] &= -1U << FLT_EXPBIT0_BIT;
m.word[0] |= (1U << (FLT_EXPBIT0_BIT - 1)) - 1;
if (!isnanf (m.value))
result |= 4;
}
#endif
return result;
}]])],
[gl_cv_func_isnanf_works=yes],
[gl_cv_func_isnanf_works=no],
[case "$host_os" in
irix* | solaris*) gl_cv_func_isnanf_works="guessing no" ;;
mingw*) # Guess yes on mingw, no on MSVC.
AC_EGREP_CPP([Known], [
#ifdef __MINGW32__
Known
#endif
],
[gl_cv_func_isnanf_works="guessing yes"],
[gl_cv_func_isnanf_works="guessing no"])
;;
*) gl_cv_func_isnanf_works="guessing yes" ;;
esac
])
])
])
|
