gnulib/import/m4/isnanl.m4

   1 # isnanl.m4 serial 19
   2 dnl Copyright (C) 2007-2016 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 AC_DEFUN([gl_FUNC_ISNANL],
   8 [
   9   AC_REQUIRE([gl_MATH_H_DEFAULTS])
  10   ISNANL_LIBM=
  11   gl_HAVE_ISNANL_NO_LIBM
  12   if test $gl_cv_func_isnanl_no_libm = no; then
  13     gl_HAVE_ISNANL_IN_LIBM
  14     if test $gl_cv_func_isnanl_in_libm = yes; then
  15       ISNANL_LIBM=-lm
  16     fi
  17   fi
  18   dnl The variable gl_func_isnanl set here is used by isnan.m4.
  19   if test $gl_cv_func_isnanl_no_libm = yes \
  20      || test $gl_cv_func_isnanl_in_libm = yes; then
  21     save_LIBS="$LIBS"
  22     LIBS="$LIBS $ISNANL_LIBM"
  23     gl_FUNC_ISNANL_WORKS
  24     LIBS="$save_LIBS"
  25     case "$gl_cv_func_isnanl_works" in
  26       *yes) gl_func_isnanl=yes ;;
  27       *)    gl_func_isnanl=no; ISNANL_LIBM= ;;
  28     esac
  29   else
  30     gl_func_isnanl=no
  31   fi
  32   if test $gl_func_isnanl != yes; then
  33     HAVE_ISNANL=0
  34   fi
  35   AC_SUBST([ISNANL_LIBM])
  36 ])
  37
  38 AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
  39 [
  40   gl_HAVE_ISNANL_NO_LIBM
  41   gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
  42   if test $gl_func_isnanl_no_libm = yes; then
  43     gl_FUNC_ISNANL_WORKS
  44     case "$gl_cv_func_isnanl_works" in
  45       *yes) ;;
  46       *)    gl_func_isnanl_no_libm=no ;;
  47     esac
  48   fi
  49   if test $gl_func_isnanl_no_libm = yes; then
  50     AC_DEFINE([HAVE_ISNANL_IN_LIBC], [1],
  51       [Define if the isnan(long double) function is available in libc.])
  52   fi
  53 ])
  54
  55 dnl Prerequisites of replacement isnanl definition. It does not need -lm.
  56 AC_DEFUN([gl_PREREQ_ISNANL],
  57 [
  58   gl_LONG_DOUBLE_EXPONENT_LOCATION
  59   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
  60 ])
  61
  62 dnl Test whether isnanl() can be used without libm.
  63 AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
  64 [
  65   AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
  66     [gl_cv_func_isnanl_no_libm],
  67     [
  68       AC_LINK_IFELSE(
  69         [AC_LANG_PROGRAM(
  70            [[#include <math.h>
  71              #if __GNUC__ >= 4
  72              # undef isnanl
  73              # define isnanl(x) __builtin_isnanl ((long double)(x))
  74              #elif defined isnan
  75              # undef isnanl
  76              # define isnanl(x) isnan ((long double)(x))
  77              #endif
  78              long double x;]],
  79            [[return isnanl (x);]])],
  80         [gl_cv_func_isnanl_no_libm=yes],
  81         [gl_cv_func_isnanl_no_libm=no])
  82     ])
  83 ])
  84
  85 dnl Test whether isnanl() can be used with libm.
  86 AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
  87 [
  88   AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
  89     [gl_cv_func_isnanl_in_libm],
  90     [
  91       save_LIBS="$LIBS"
  92       LIBS="$LIBS -lm"
  93       AC_LINK_IFELSE(
  94         [AC_LANG_PROGRAM(
  95            [[#include <math.h>
  96              #if __GNUC__ >= 4
  97              # undef isnanl
  98              # define isnanl(x) __builtin_isnanl ((long double)(x))
  99              #elif defined isnan
 100              # undef isnanl
 101              # define isnanl(x) isnan ((long double)(x))
 102              #endif
 103              long double x;]],
 104            [[return isnanl (x);]])],
 105         [gl_cv_func_isnanl_in_libm=yes],
 106         [gl_cv_func_isnanl_in_libm=no])
 107       LIBS="$save_LIBS"
 108     ])
 109 ])
 110
 111 dnl Test whether isnanl() recognizes all canonical numbers which are neither
 112 dnl finite nor infinite.
 113 AC_DEFUN([gl_FUNC_ISNANL_WORKS],
 114 [
 115   AC_REQUIRE([AC_PROG_CC])
 116   AC_REQUIRE([gl_BIGENDIAN])
 117   AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
 118   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
 119   AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
 120     [
 121       AC_RUN_IFELSE(
 122         [AC_LANG_SOURCE([[
 123 #include <float.h>
 124 #include <limits.h>
 125 #include <math.h>
 126 #if __GNUC__ >= 4
 127 # undef isnanl
 128 # define isnanl(x) __builtin_isnanl ((long double)(x))
 129 #elif defined isnan
 130 # undef isnanl
 131 # define isnanl(x) isnan ((long double)(x))
 132 #endif
 133 #define NWORDS \
 134   ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
 135 typedef union { unsigned int word[NWORDS]; long double value; }
 136         memory_long_double;
 137 /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
 138    runtime type conversion.  */
 139 #ifdef __sgi
 140 static long double NaNl ()
 141 {
 142   double zero = 0.0;
 143   return zero / zero;
 144 }
 145 #else
 146 # define NaNl() (0.0L / 0.0L)
 147 #endif
 148 int main ()
 149 {
 150   int result = 0;
 151
 152   if (!isnanl (NaNl ()))
 153     result |= 1;
 154
 155   {
 156     memory_long_double m;
 157     unsigned int i;
 158
 159     /* The isnanl function should be immune against changes in the sign bit and
 160        in the mantissa bits.  The xor operation twiddles a bit that can only be
 161        a sign bit or a mantissa bit (since the exponent never extends to
 162        bit 31).  */
 163     m.value = NaNl ();
 164     m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
 165     for (i = 0; i < NWORDS; i++)
 166       m.word[i] |= 1;
 167     if (!isnanl (m.value))
 168       result |= 1;
 169   }
 170
 171 #if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
 172 /* Representation of an 80-bit 'long double' as an initializer for a sequence
 173    of 'unsigned int' words.  */
 174 # ifdef WORDS_BIGENDIAN
 175 #  define LDBL80_WORDS(exponent,manthi,mantlo) \
 176      { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
 177        ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16),   \
 178        (unsigned int) (mantlo) << 16                                        \
 179      }
 180 # else
 181 #  define LDBL80_WORDS(exponent,manthi,mantlo) \
 182      { mantlo, manthi, exponent }
 183 # endif
 184   { /* Quiet NaN.  */
 185     static memory_long_double x =
 186       { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
 187     if (!isnanl (x.value))
 188       result |= 2;
 189   }
 190   {
 191     /* Signalling NaN.  */
 192     static memory_long_double x =
 193       { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
 194     if (!isnanl (x.value))
 195       result |= 2;
 196   }
 197   /* isnanl should return something even for noncanonical values.  */
 198   { /* Pseudo-NaN.  */
 199     static memory_long_double x =
 200       { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
 201     if (isnanl (x.value) && !isnanl (x.value))
 202       result |= 4;
 203   }
 204   { /* Pseudo-Infinity.  */
 205     static memory_long_double x =
 206       { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
 207     if (isnanl (x.value) && !isnanl (x.value))
 208       result |= 8;
 209   }
 210   { /* Pseudo-Zero.  */
 211     static memory_long_double x =
 212       { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
 213     if (isnanl (x.value) && !isnanl (x.value))
 214       result |= 16;
 215   }
 216   { /* Unnormalized number.  */
 217     static memory_long_double x =
 218       { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
 219     if (isnanl (x.value) && !isnanl (x.value))
 220       result |= 32;
 221   }
 222   { /* Pseudo-Denormal.  */
 223     static memory_long_double x =
 224       { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
 225     if (isnanl (x.value) && !isnanl (x.value))
 226       result |= 64;
 227   }
 228 #endif
 229
 230   return result;
 231 }]])],
 232         [gl_cv_func_isnanl_works=yes],
 233         [gl_cv_func_isnanl_works=no],
 234         [gl_cv_func_isnanl_works="guessing yes"])
 235     ])
 236 ])