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Diffstat (limited to 'gnulib_m4/isnanf.m4')
| -rw-r--r-- | gnulib_m4/isnanf.m4 | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/gnulib_m4/isnanf.m4 b/gnulib_m4/isnanf.m4 new file mode 100644 index 0000000..01f7bbd --- /dev/null +++ b/gnulib_m4/isnanf.m4 @@ -0,0 +1,197 @@ +# isnanf.m4 serial 18 +dnl Copyright (C) 2007-2023 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 + ]) + ]) +]) |