-# isfinite.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# isfinite.m4 serial 13
+dnl Copyright (C) 2007-2013 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.
AC_REQUIRE([gl_MATH_H_DEFAULTS])
dnl Persuade glibc <math.h> to declare isfinite.
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
- AC_CHECK_DECLS([isfinite], , , [#include <math.h>])
+ AC_CHECK_DECLS([isfinite], , , [[#include <math.h>]])
if test "$ac_cv_have_decl_isfinite" = yes; then
- gl_CHECK_MATH_LIB([ISFINITE_LIBM], [x = isfinite (x);])
+ gl_CHECK_MATH_LIB([ISFINITE_LIBM],
+ [x = isfinite (x) + isfinite ((float) x);])
+ if test "$ISFINITE_LIBM" != missing; then
+ dnl Test whether isfinite() on 'long double' works.
+ gl_ISFINITEL_WORKS
+ case "$gl_cv_func_isfinitel_works" in
+ *yes) ;;
+ *) ISFINITE_LIBM=missing;;
+ esac
+ dnl Also, isfinite() on 'double' does not work on Linux/ia64 (because of
+ dnl signalling NaNs). But this does not have to be tested, since
+ dnl isfinite(long double) also does not work in this situation.
+ fi
fi
if test "$ac_cv_have_decl_isfinite" != yes ||
test "$ISFINITE_LIBM" = missing; then
REPLACE_ISFINITE=1
- AC_LIBOBJ([isfinite])
+ dnl No libraries are needed to link lib/isfinite.c.
ISFINITE_LIBM=
fi
- AC_SUBST([REPLACE_ISFINITE])
AC_SUBST([ISFINITE_LIBM])
])
+
+dnl Test whether isfinite() on 'long double' recognizes all numbers which are
+dnl neither finite nor infinite. This test fails e.g. on i686, x86_64, ia64,
+dnl because of
+dnl - pseudo-denormals on x86_64,
+dnl - pseudo-zeroes, unnormalized numbers, and pseudo-denormals on i686,
+dnl - pseudo-NaN, pseudo-Infinity, pseudo-zeroes, unnormalized numbers, and
+dnl pseudo-denormals on ia64.
+AC_DEFUN([gl_ISFINITEL_WORKS],
+[
+ AC_REQUIRE([AC_PROG_CC])
+ AC_REQUIRE([gl_BIGENDIAN])
+ AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether isfinite(long double) works], [gl_cv_func_isfinitel_works],
+ [
+ AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <float.h>
+#include <limits.h>
+#include <math.h>
+#define NWORDS \
+ ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { unsigned int word[NWORDS]; long double value; }
+ memory_long_double;
+/* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
+ runtime type conversion. */
+#ifdef __sgi
+static long double NaNl ()
+{
+ double zero = 0.0;
+ return zero / zero;
+}
+#else
+# define NaNl() (0.0L / 0.0L)
+#endif
+int main ()
+{
+ int result = 0;
+
+ {
+ memory_long_double m;
+ unsigned int i;
+
+ /* The isfinite macro 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 (since the exponent never extends to
+ bit 31). */
+ m.value = NaNl ();
+ m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+ for (i = 0; i < NWORDS; i++)
+ m.word[i] |= 1;
+ if (isfinite (m.value))
+ result |= 1;
+ }
+
+#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
+/* Representation of an 80-bit 'long double' as an initializer for a sequence
+ of 'unsigned int' words. */
+# ifdef WORDS_BIGENDIAN
+# define LDBL80_WORDS(exponent,manthi,mantlo) \
+ { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
+ ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16), \
+ (unsigned int) (mantlo) << 16 \
+ }
+# else
+# define LDBL80_WORDS(exponent,manthi,mantlo) \
+ { mantlo, manthi, exponent }
+# endif
+ { /* Quiet NaN. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 2;
+ }
+ {
+ /* Signalling NaN. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 2;
+ }
+ /* The isfinite macro should recognize Pseudo-NaNs, Pseudo-Infinities,
+ Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
+ Intel IA-64 Architecture Software Developer's Manual, Volume 1:
+ Application Architecture.
+ Table 5-2 "Floating-Point Register Encodings"
+ Figure 5-6 "Memory to Floating-Point Register Data Translation"
+ */
+ { /* Pseudo-NaN. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 4;
+ }
+ { /* Pseudo-Infinity. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 8;
+ }
+ { /* Pseudo-Zero. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 16;
+ }
+ { /* Unnormalized number. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 32;
+ }
+ { /* Pseudo-Denormal. */
+ static memory_long_double x =
+ { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
+ if (isfinite (x.value))
+ result |= 64;
+ }
+#endif
+
+ return result;
+}]])], [gl_cv_func_isfinitel_works=yes], [gl_cv_func_isfinitel_works=no],
+ [case "$host_cpu" in
+ # Guess no on ia64, x86_64, i386.
+ ia64 | x86_64 | i*86) gl_cv_func_isfinitel_works="guessing no";;
+ *) gl_cv_func_isfinitel_works="guessing yes";;
+ esac
+ ])
+ ])
+])
projects / gnulib.git / blobdiff