# isnanf.m4 serial 15

dnl Copyright (C) 2007-2018 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

             # undef isnanf

             # define isnanf(x) __builtin_isnanf ((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

             # undef isnanf

             # define isnanf(x) __builtin_isnanf ((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

# undef isnanf

# define isnanf(x) __builtin_isnanf ((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

        ])

    ])

])