1# isnanl.m4 serial 17
2dnl Copyright (C) 2007-2012 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_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 $gl_func_isnanl != yes; then
33    HAVE_ISNANL=0
34  fi
35  AC_SUBST([ISNANL_LIBM])
36])
37
38AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
39[
40  gl_HAVE_ISNANL_NO_LIBM
41  gl_func_isnanl_no_libm=$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 $gl_func_isnanl_no_libm = yes; then
50    AC_DEFINE([HAVE_ISNANL_IN_LIBC], [1],
51      [Define if the isnan(long double) function is available in libc.])
52  fi
53])
54
55dnl Prerequisites of replacement isnanl definition. It does not need -lm.
56AC_DEFUN([gl_PREREQ_ISNANL],
57[
58  gl_LONG_DOUBLE_EXPONENT_LOCATION
59  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
60])
61
62dnl Test whether isnanl() can be used without libm.
63AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
64[
65  AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
66    [gl_cv_func_isnanl_no_libm],
67    [
68      AC_LINK_IFELSE(
69        [AC_LANG_PROGRAM(
70           [[#include <math.h>
71             #if __GNUC__ >= 4
72             # undef isnanl
73             # define isnanl(x) __builtin_isnanl ((long double)(x))
74             #elif defined isnan
75             # undef isnanl
76             # define isnanl(x) isnan ((long double)(x))
77             #endif
78             long double x;]],
79           [[return isnanl (x);]])],
80        [gl_cv_func_isnanl_no_libm=yes],
81        [gl_cv_func_isnanl_no_libm=no])
82    ])
83])
84
85dnl Test whether isnanl() can be used with libm.
86AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
87[
88  AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
89    [gl_cv_func_isnanl_in_libm],
90    [
91      save_LIBS="$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
111dnl Test whether isnanl() recognizes all numbers which are neither finite nor
112dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
113dnl Also, the GCC >= 4.0 built-in __builtin_isnanl does not pass the tests
114dnl - for pseudo-denormals on i686 and x86_64,
115dnl - for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
116AC_DEFUN([gl_FUNC_ISNANL_WORKS],
117[
118  AC_REQUIRE([AC_PROG_CC])
119  AC_REQUIRE([gl_BIGENDIAN])
120  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
121  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
122  AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
123    [
124      AC_RUN_IFELSE(
125        [AC_LANG_SOURCE([[
126#include <float.h>
127#include <limits.h>
128#include <math.h>
129#if __GNUC__ >= 4
130# undef isnanl
131# define isnanl(x) __builtin_isnanl ((long double)(x))
132#elif defined isnan
133# undef isnanl
134# define isnanl(x) isnan ((long double)(x))
135#endif
136#define NWORDS \
137  ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
138typedef union { unsigned int word[NWORDS]; long double value; }
139        memory_long_double;
140/* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
141   runtime type conversion.  */
142#ifdef __sgi
143static long double NaNl ()
144{
145  double zero = 0.0;
146  return zero / zero;
147}
148#else
149# define NaNl() (0.0L / 0.0L)
150#endif
151int main ()
152{
153  int result = 0;
154
155  if (!isnanl (NaNl ()))
156    result |= 1;
157
158  {
159    memory_long_double m;
160    unsigned int i;
161
162    /* The isnanl function should be immune against changes in the sign bit and
163       in the mantissa bits.  The xor operation twiddles a bit that can only be
164       a sign bit or a mantissa bit (since the exponent never extends to
165       bit 31).  */
166    m.value = NaNl ();
167    m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
168    for (i = 0; i < NWORDS; i++)
169      m.word[i] |= 1;
170    if (!isnanl (m.value))
171      result |= 1;
172  }
173
174#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
175/* Representation of an 80-bit 'long double' as an initializer for a sequence
176   of 'unsigned int' words.  */
177# ifdef WORDS_BIGENDIAN
178#  define LDBL80_WORDS(exponent,manthi,mantlo) \
179     { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
180       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
181       (unsigned int) (mantlo) << 16                                        \
182     }
183# else
184#  define LDBL80_WORDS(exponent,manthi,mantlo) \
185     { mantlo, manthi, exponent }
186# endif
187  { /* Quiet NaN.  */
188    static memory_long_double x =
189      { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
190    if (!isnanl (x.value))
191      result |= 2;
192  }
193  {
194    /* Signalling NaN.  */
195    static memory_long_double x =
196      { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
197    if (!isnanl (x.value))
198      result |= 2;
199  }
200  /* The isnanl function should recognize Pseudo-NaNs, Pseudo-Infinities,
201     Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
202       Intel IA-64 Architecture Software Developer's Manual, Volume 1:
203       Application Architecture.
204       Table 5-2 "Floating-Point Register Encodings"
205       Figure 5-6 "Memory to Floating-Point Register Data Translation"
206   */
207  { /* Pseudo-NaN.  */
208    static memory_long_double x =
209      { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
210    if (!isnanl (x.value))
211      result |= 4;
212  }
213  { /* Pseudo-Infinity.  */
214    static memory_long_double x =
215      { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
216    if (!isnanl (x.value))
217      result |= 8;
218  }
219  { /* Pseudo-Zero.  */
220    static memory_long_double x =
221      { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
222    if (!isnanl (x.value))
223      result |= 16;
224  }
225  { /* Unnormalized number.  */
226    static memory_long_double x =
227      { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
228    if (!isnanl (x.value))
229      result |= 32;
230  }
231  { /* Pseudo-Denormal.  */
232    static memory_long_double x =
233      { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
234    if (!isnanl (x.value))
235      result |= 64;
236  }
237#endif
238
239  return result;
240}]])],
241        [gl_cv_func_isnanl_works=yes],
242        [gl_cv_func_isnanl_works=no],
243        [case "$host_cpu" in
244                                 # Guess no on ia64, x86_64, i386.
245           ia64 | x86_64 | i*86) gl_cv_func_isnanl_works="guessing no";;
246           *)
247             case "$host_os" in
248               netbsd*) gl_cv_func_isnanl_works="guessing no";;
249               *)       gl_cv_func_isnanl_works="guessing yes";;
250             esac
251             ;;
252         esac
253        ])
254    ])
255])
256