From: Bruno Haible Date: Sat, 1 Oct 2011 10:07:28 +0000 (+0200) Subject: isinf: Fix for OpenBSD/x86. X-Git-Tag: v0.1~1718 X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=0439f6f0de51b9e9c1f76d91dd4bcbe58a5f8dc0;p=gnulib.git isinf: Fix for OpenBSD/x86. * m4/isinf.m4 (gl_ISINFL_WORKS): Also test the behaviour of isinf on pseudo-NaNs, pseudo-Infinities, and other non-IEEE values. * doc/posix-functions/isinf.texi: Mention the problem on OpenBSD/x86. --- diff --git a/ChangeLog b/ChangeLog index 0d2bc0da5..d60071b28 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,12 @@ 2011-10-01 Bruno Haible + isinf: Fix for OpenBSD/x86. + * m4/isinf.m4 (gl_ISINFL_WORKS): Also test the behaviour of isinf on + pseudo-NaNs, pseudo-Infinities, and other non-IEEE values. + * doc/posix-functions/isinf.texi: Mention the problem on OpenBSD/x86. + +2011-10-01 Bruno Haible + isfinite: Fix syntax error in configure test. * m4/isfinite.m4 (gl_ISFINITEL_WORKS): Fix syntax error. diff --git a/doc/posix-functions/isinf.texi b/doc/posix-functions/isinf.texi index a1f7a3464..8ef4b4db0 100644 --- a/doc/posix-functions/isinf.texi +++ b/doc/posix-functions/isinf.texi @@ -11,6 +11,10 @@ Portability problems fixed by Gnulib: @item This macro is missing on some platforms: AIX 4.3.2, IRIX 6.5, OSF/1 5.1, Solaris 11 2010-11. +@item +This macro incorrectly yields true for some @samp{long double} arguments, on +some platforms: +OpenBSD 4.9/x86 (pseudo-Infinity). @end itemize Portability problems not fixed by Gnulib: diff --git a/m4/isinf.m4 b/m4/isinf.m4 index d18f367da..4c819a48b 100644 --- a/m4/isinf.m4 +++ b/m4/isinf.m4 @@ -1,4 +1,4 @@ -# isinf.m4 serial 6 +# isinf.m4 serial 7 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -30,7 +30,15 @@ AC_DEFUN([gl_ISINF], AC_SUBST([ISINF_LIBM]) ]) -dnl Test whether isinf() correctly returns false for LDBL_MAX. +dnl Test whether isinf() works: +dnl 1) Whether it correctly returns false for LDBL_MAX. +dnl 2) Whether on 'long double' recognizes all numbers which are neither +dnl finite nor infinite. This test fails on OpenBSD/x86, but could also +dnl fail e.g. on i686, x86_64, ia64, 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_ISINFL_WORKS], [ AC_REQUIRE([AC_PROG_CC]) @@ -38,11 +46,124 @@ AC_DEFUN([gl_ISINFL_WORKS], AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether isinf(long double) works], [gl_cv_func_isinfl_works], [ - AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include - #include ]], - [[return !!isinf(LDBL_MAX);]])], - [gl_cv_func_isinfl_works=yes], - [gl_cv_func_isinfl_works=no], - [gl_cv_func_isinfl_works="guessing no"]) + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#include +#include +#include +#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; + + if (isinf (LDBL_MAX)) + result |= 1; + + { + memory_long_double m; + unsigned int i; + + /* The isinf 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 (isinf (m.value)) + result |= 2; + } + +#if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) +/* 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 (isinf (x.value)) + result |= 2; + } + { + /* Signalling NaN. */ + static memory_long_double x = + { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) }; + if (isinf (x.value)) + result |= 2; + } + /* The isinf 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 (isinf (x.value)) + result |= 4; + } + { /* Pseudo-Infinity. */ + static memory_long_double x = + { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) }; + if (isinf (x.value)) + result |= 8; + } + { /* Pseudo-Zero. */ + static memory_long_double x = + { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) }; + if (isinf (x.value)) + result |= 16; + } + { /* Unnormalized number. */ + static memory_long_double x = + { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) }; + if (isinf (x.value)) + result |= 32; + } + { /* Pseudo-Denormal. */ + static memory_long_double x = + { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) }; + if (isinf (x.value)) + result |= 64; + } +#endif + + return result; +}]])], [gl_cv_func_isinfl_works=yes], [gl_cv_func_isinfl_works=no], + [ + case "$host" in + # Guess no on OpenBSD ia64, x86_64, i386. + ia64-*-openbsd* | x86_64-*-openbsd* | i*86-*-openbsd*) + gl_cv_func_isinfl_works="guessing no";; + *) + gl_cv_func_isinfl_works="guessing yes";; + esac + ]) ]) ])