1 # isnanf.m4 serial 14 2 dnl Copyright (C) 2007-2012 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 dnl Check how to get or define isnanf(). 8 9 AC_DEFUN([gl_FUNC_ISNANF], 10 [ 11 AC_REQUIRE([gl_MATH_H_DEFAULTS]) 12 ISNANF_LIBM= 13 gl_HAVE_ISNANF_NO_LIBM 14 if test $gl_cv_func_isnanf_no_libm = no; then 15 gl_HAVE_ISNANF_IN_LIBM 16 if test $gl_cv_func_isnanf_in_libm = yes; then 17 ISNANF_LIBM=-lm 18 fi 19 fi 20 dnl The variable gl_func_isnanf set here is used by isnan.m4. 21 if test $gl_cv_func_isnanf_no_libm = yes \ 22 || test $gl_cv_func_isnanf_in_libm = yes; then 23 save_LIBS="$LIBS" 24 LIBS="$LIBS $ISNANF_LIBM" 25 gl_ISNANF_WORKS 26 LIBS="$save_LIBS" 27 case "$gl_cv_func_isnanf_works" in 28 *yes) gl_func_isnanf=yes ;; 29 *) gl_func_isnanf=no; ISNANF_LIBM= ;; 30 esac 31 else 32 gl_func_isnanf=no 33 fi 34 if test $gl_func_isnanf != yes; then 35 HAVE_ISNANF=0 36 fi 37 AC_SUBST([ISNANF_LIBM]) 38 ]) 39 40 dnl Check how to get or define isnanf() without linking with libm. 41 42 AC_DEFUN([gl_FUNC_ISNANF_NO_LIBM], 43 [ 44 gl_HAVE_ISNANF_NO_LIBM 45 if test $gl_cv_func_isnanf_no_libm = yes; then 46 gl_ISNANF_WORKS 47 fi 48 if test $gl_cv_func_isnanf_no_libm = yes \ 49 && { case "$gl_cv_func_isnanf_works" in 50 *yes) true;; 51 *) false;; 52 esac 53 }; then 54 gl_func_isnanf_no_libm=yes 55 AC_DEFINE([HAVE_ISNANF_IN_LIBC], [1], 56 [Define if the isnan(float) function is available in libc.]) 57 else 58 gl_func_isnanf_no_libm=no 59 fi 60 ]) 61 62 dnl Prerequisites of replacement isnanf definition. It does not need -lm. 63 AC_DEFUN([gl_PREREQ_ISNANF], 64 [ 65 gl_FLOAT_EXPONENT_LOCATION 66 ]) 67 68 dnl Test whether isnanf() can be used without libm. 69 AC_DEFUN([gl_HAVE_ISNANF_NO_LIBM], 70 [ 71 AC_CACHE_CHECK([whether isnan(float) can be used without linking with libm], 72 [gl_cv_func_isnanf_no_libm], 73 [ 74 AC_LINK_IFELSE( 75 [AC_LANG_PROGRAM( 76 [[#include <math.h> 77 #if __GNUC__ >= 4 78 # undef isnanf 79 # define isnanf(x) __builtin_isnanf ((float)(x)) 80 #elif defined isnan 81 # undef isnanf 82 # define isnanf(x) isnan ((float)(x)) 83 #endif 84 float x;]], 85 [[return isnanf (x);]])], 86 [gl_cv_func_isnanf_no_libm=yes], 87 [gl_cv_func_isnanf_no_libm=no]) 88 ]) 89 ]) 90 91 dnl Test whether isnanf() can be used with libm. 92 AC_DEFUN([gl_HAVE_ISNANF_IN_LIBM], 93 [ 94 AC_CACHE_CHECK([whether isnan(float) can be used with libm], 95 [gl_cv_func_isnanf_in_libm], 96 [ 97 save_LIBS="$LIBS" 98 LIBS="$LIBS -lm" 99 AC_LINK_IFELSE( 100 [AC_LANG_PROGRAM( 101 [[#include <math.h> 102 #if __GNUC__ >= 4 103 # undef isnanf 104 # define isnanf(x) __builtin_isnanf ((float)(x)) 105 #elif defined isnan 106 # undef isnanf 107 # define isnanf(x) isnan ((float)(x)) 108 #endif 109 float x;]], 110 [[return isnanf (x);]])], 111 [gl_cv_func_isnanf_in_libm=yes], 112 [gl_cv_func_isnanf_in_libm=no]) 113 LIBS="$save_LIBS" 114 ]) 115 ]) 116 117 dnl Test whether isnanf() rejects Infinity (this fails on Solaris 2.5.1), 118 dnl recognizes a NaN (this fails on IRIX 6.5 with cc), and recognizes a NaN 119 dnl with in-memory representation 0x7fbfffff (this fails on IRIX 6.5). 120 AC_DEFUN([gl_ISNANF_WORKS], 121 [ 122 AC_REQUIRE([AC_PROG_CC]) 123 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles 124 AC_REQUIRE([gl_FLOAT_EXPONENT_LOCATION]) 125 AC_CACHE_CHECK([whether isnan(float) works], [gl_cv_func_isnanf_works], 126 [ 127 AC_RUN_IFELSE( 128 [AC_LANG_SOURCE([[ 129 #include <math.h> 130 #if __GNUC__ >= 4 131 # undef isnanf 132 # define isnanf(x) __builtin_isnanf ((float)(x)) 133 #elif defined isnan 134 # undef isnanf 135 # define isnanf(x) isnan ((float)(x)) 136 #endif 137 /* The Compaq (ex-DEC) C 6.4 compiler chokes on the expression 0.0 / 0.0. */ 138 #ifdef __DECC 139 static float 140 NaN () 141 { 142 static float zero = 0.0f; 143 return zero / zero; 144 } 145 #else 146 # define NaN() (0.0f / 0.0f) 147 #endif 148 #define NWORDS \ 149 ((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int)) 150 typedef union { unsigned int word[NWORDS]; float value; } memory_float; 151 int main() 152 { 153 int result = 0; 154 155 if (isnanf (1.0f / 0.0f)) 156 result |= 1; 157 158 if (!isnanf (NaN ())) 159 result |= 2; 160 161 #if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT 162 /* The isnanf 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. */ 165 if (FLT_EXPBIT0_WORD == 0 && FLT_EXPBIT0_BIT > 0) 166 { 167 memory_float m; 168 169 m.value = NaN (); 170 /* Set the bits below the exponent to 01111...111. */ 171 m.word[0] &= -1U << FLT_EXPBIT0_BIT; 172 m.word[0] |= 1U << (FLT_EXPBIT0_BIT - 1) - 1; 173 if (!isnanf (m.value)) 174 result |= 4; 175 } 176 #endif 177 178 return result; 179 }]])], 180 [gl_cv_func_isnanf_works=yes], 181 [gl_cv_func_isnanf_works=no], 182 [case "$host_os" in 183 irix* | solaris*) gl_cv_func_isnanf_works="guessing no";; 184 *) gl_cv_func_isnanf_works="guessing yes";; 185 esac 186 ]) 187 ]) 188 ]) 189
