-# isnanf.m4 serial 2
-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_ISNANF_WORKS
fi
if test $gl_cv_func_isnanf_no_libm = yes \
- && test $gl_cv_func_isnanf_works = yes; then
- AC_DEFINE([HAVE_ISNANF_IN_LIBC], 1,
+ && { case "$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 <math.h>
- #ifdef isnan
- # undef isnanf
- # define isnanf(x) isnan ((float)(x))
- #endif
- float x;],
- [return isnanf (x);],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ #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])
])
])
-dnl Test whether isnanf() recognizes a NaN (this fails on IRIX 6.5) and rejects
-dnl Infinity (this fails on Solaris 2.5.1).
+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
+ # 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="$save_LIBS"
+ ])
+])
+
+dnl Test whether isnanf() rejects Infinity (this fails on Solaris 2.5.1),
+dnl recognizes a NaN (this fails on IRIX 6.5 with cc), and recognizes a NaN
+dnl with in-memory representation 0x7fbfffff (this fails on IRIX 6.5).
AC_DEFUN([gl_ISNANF_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_REQUIRE([gl_FLOAT_EXPONENT_LOCATION])
AC_CACHE_CHECK([whether isnan(float) works], [gl_cv_func_isnanf_works],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#include <math.h>
-#ifdef isnan
+#if __GNUC__ >= 4
+# undef isnanf
+# define isnanf(x) __builtin_isnanf ((float)(x))
+#elif defined isnan
# undef isnanf
# define isnanf(x) isnan ((float)(x))
#endif
#else
# define NaN() (0.0f / 0.0f)
#endif
+#define NWORDS \
+ ((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { unsigned int word[NWORDS]; float value; } memory_float;
int main()
{
- if (!isnanf (NaN ()))
- return 1;
+ int result = 0;
+
if (isnanf (1.0f / 0.0f))
- return 1;
- return 0;
-}], [gl_cv_func_isnanf_works=yes], [gl_cv_func_isnanf_works=no],
+ result |= 1;
+
+ if (!isnanf (NaN ()))
+ result |= 2;
+
+#if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
+ /* The isnanf function should be immune against changes in the sign bit and
+ in the mantissa bits. The xor operation twiddles a bit that can only be
+ a sign bit or a mantissa bit. */
+ if (FLT_EXPBIT0_WORD == 0 && FLT_EXPBIT0_BIT > 0)
+ {
+ memory_float m;
+
+ m.value = NaN ();
+ /* Set the bits below the exponent to 01111...111. */
+ m.word[0] &= -1U << FLT_EXPBIT0_BIT;
+ m.word[0] |= 1U << (FLT_EXPBIT0_BIT - 1) - 1;
+ if (!isnanf (m.value))
+ result |= 4;
+ }
+#endif
+
+ return result;
+}]])],
+ [gl_cv_func_isnanf_works=yes],
+ [gl_cv_func_isnanf_works=no],
[case "$host_os" in
irix* | solaris*) gl_cv_func_isnanf_works="guessing no";;
*) gl_cv_func_isnanf_works="guessing yes";;
])
])
])
-
-AC_DEFUN([gl_FLOAT_EXPONENT_LOCATION],
-[
- AC_CACHE_CHECK([where to find the exponent in a 'float'],
- [gl_cv_cc_float_expbit0],
- [
- AC_TRY_RUN([
-#include <float.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
-#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)
-{
- 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];
- }
-}
-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)
- {
- 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);
- }
- }
- 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
- ])
- 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
-])
projects / gnulib.git / blobdiff