X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fisnanf.m4;h=1f2717d5e573f010996339b4be66196d10ef04e3;hb=1276a2c5f24c0c932426aca9c899fa524d2443f2;hp=ddc17a841376175504b67c356f38f2dfc0a28924;hpb=15b93a23d220ccdf3d29bf6f9b8fbf7e50269f9f;p=gnulib.git diff --git a/m4/isnanf.m4 b/m4/isnanf.m4 index ddc17a841..1f2717d5e 100644 --- a/m4/isnanf.m4 +++ b/m4/isnanf.m4 @@ -1,124 +1,188 @@ -# isnanf.m4 serial 1 -dnl Copyright (C) 2007 Free Software Foundation, Inc. +# isnanf.m4 serial 14 +dnl Copyright (C) 2007-2014 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 - AC_DEFINE([HAVE_ISNANF_IN_LIBC], 1, + 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 - AC_LIBOBJ([isnanf]) - gl_FLOAT_EXPONENT_LOCATION + 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_TRY_LINK([#include - #ifdef isnan - # undef isnanf - # define isnanf(x) isnan ((float)(x)) - #endif - float x;], - [return isnanf (x);], + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include + #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]) ]) ]) -AC_DEFUN([gl_FLOAT_EXPONENT_LOCATION], +dnl Test whether isnanf() can be used with libm. +AC_DEFUN([gl_HAVE_ISNANF_IN_LIBM], [ - AC_CACHE_CHECK([where to find the exponent in a 'float'], - [gl_cv_cc_float_expbit0], + AC_CACHE_CHECK([whether isnan(float) can be used with libm], + [gl_cv_func_isnanf_in_libm], [ - AC_TRY_RUN([ -#include -#include -#include -#include -#define NWORDS \ - ((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int)) -typedef union { float value; unsigned int word[NWORDS]; } memory_float; -static unsigned int ored_words[NWORDS]; -static unsigned int anded_words[NWORDS]; -static void add_to_ored_words (float x) + save_LIBS="$LIBS" + LIBS="$LIBS -lm" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#include + #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 +#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 () { - memory_float m; - size_t i; - /* Clear it first, in case - sizeof (float) < sizeof (memory_float). */ - memset (&m, 0, sizeof (memory_float)); - m.value = x; - for (i = 0; i < NWORDS; i++) - { - ored_words[i] |= m.word[i]; - anded_words[i] &= m.word[i]; - } + static float zero = 0.0f; + return zero / zero; } -int main () +#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() { - size_t j; - FILE *fp = fopen ("conftest.out", "w"); - if (fp == NULL) - return 1; - for (j = 0; j < NWORDS; j++) - anded_words[j] = ~ (unsigned int) 0; - add_to_ored_words (0.25f); - add_to_ored_words (0.5f); - add_to_ored_words (1.0f); - add_to_ored_words (2.0f); - add_to_ored_words (4.0f); - /* Remove bits that are common (e.g. if representation of the first mantissa - bit is explicit). */ - for (j = 0; j < NWORDS; j++) - ored_words[j] &= ~anded_words[j]; - /* Now find the nonzero word. */ - for (j = 0; j < NWORDS; j++) - if (ored_words[j] != 0) - break; - if (j < NWORDS) + 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) { - size_t i; - for (i = j + 1; i < NWORDS; i++) - if (ored_words[i] != 0) - { - fprintf (fp, "unknown"); - return (fclose (fp) != 0); - } - for (i = 0; ; i++) - if ((ored_words[j] >> i) & 1) - { - fprintf (fp, "word %d bit %d", (int) j, (int) i); - return (fclose (fp) != 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; } - fprintf (fp, "unknown"); - return (fclose (fp) != 0); -} - ], - [gl_cv_cc_float_expbit0=`cat conftest.out`], - [gl_cv_cc_float_expbit0="unknown"], - [gl_cv_cc_double_expbit0="word 0 bit 23"]) - rm -f conftest.out +#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";; + *) gl_cv_func_isnanf_works="guessing yes";; + esac + ]) ]) - case "$gl_cv_cc_float_expbit0" in - word*bit*) - word=`echo "$gl_cv_cc_float_expbit0" | sed -e 's/word //' -e 's/ bit.*//'` - bit=`echo "$gl_cv_cc_float_expbit0" | sed -e 's/word.*bit //'` - AC_DEFINE_UNQUOTED([FLT_EXPBIT0_WORD], [$word], - [Define as the word index where to find the exponent of 'float'.]) - AC_DEFINE_UNQUOTED([FLT_EXPBIT0_BIT], [$bit], - [Define as the bit index in the word where to find bit 0 of the exponent of 'float'.]) - ;; - esac ])