From 937471dbdf6a976b39d2e5f20e9817d368497e43 Mon Sep 17 00:00:00 2001 From: Bruno Haible Date: Wed, 14 Mar 2012 03:25:16 +0100 Subject: [PATCH] hypotl: Bypass broken implementation in OpenBSD 5.1/SPARC. * m4/hypotl.m4 (gl_FUNC_HYPOTL_WORKS): New macro. (gl_FUNC_HYPOTL): Invoke it. If the function does not work, set REPLACE_HYPOTL to 1. * doc/posix-functions/hypotl.texi: Mention the OpenBSD 5.1/SPARC bug. --- ChangeLog | 8 ++++++ doc/posix-functions/hypotl.texi | 3 ++ m4/hypotl.m4 | 64 ++++++++++++++++++++++++++++++++++++++++- 3 files changed, 74 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index f1c464f02..bd1b23419 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2012-03-13 Bruno Haible + hypotl: Bypass broken implementation in OpenBSD 5.1/SPARC. + * m4/hypotl.m4 (gl_FUNC_HYPOTL_WORKS): New macro. + (gl_FUNC_HYPOTL): Invoke it. If the function does not work, set + REPLACE_HYPOTL to 1. + * doc/posix-functions/hypotl.texi: Mention the OpenBSD 5.1/SPARC bug. + +2012-03-13 Bruno Haible + remainderl: Bypass broken implementation in OpenBSD 5.1/SPARC. * m4/remainderl.m4 (gl_FUNC_REMAINDERL_WORKS): New macro. (gl_FUNC_REMAINDERL): Invoke it. If the function does not work, set diff --git a/doc/posix-functions/hypotl.texi b/doc/posix-functions/hypotl.texi index 630f5b47b..1c6b06496 100644 --- a/doc/posix-functions/hypotl.texi +++ b/doc/posix-functions/hypotl.texi @@ -11,6 +11,9 @@ Portability problems fixed by either Gnulib module @code{hypotl} or @code{hypotl @item This function is missing on some platforms: FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, Cygwin, MSVC 9, Interix 3.5, BeOS. +@item +This function produces very imprecise results on some platforms: +OpenBSD 5.1/SPARC. @end itemize Portability problems fixed by Gnulib module @code{hypotl-ieee}: diff --git a/m4/hypotl.m4 b/m4/hypotl.m4 index e7b0eb242..7af4cb0ef 100644 --- a/m4/hypotl.m4 +++ b/m4/hypotl.m4 @@ -1,4 +1,4 @@ -# hypotl.m4 serial 3 +# hypotl.m4 serial 4 dnl Copyright (C) 2012 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -21,6 +21,16 @@ AC_DEFUN([gl_FUNC_HYPOTL], LIBS="$save_LIBS" if test $ac_cv_func_hypotl = yes; then HYPOTL_LIBM="$HYPOT_LIBM" + + save_LIBS="$LIBS" + LIBS="$LIBS $HYPOTL_LIBM" + gl_FUNC_HYPOTL_WORKS + LIBS="$save_LIBS" + case "$gl_cv_func_hypotl_works" in + *yes) ;; + *) REPLACE_HYPOTL=1 ;; + esac + m4_ifdef([gl_FUNC_HYPOTL_IEEE], [ if test $gl_hypotl_required = ieee && test $REPLACE_HYPOTL = 0; then AC_CACHE_CHECK([whether hypotl works according to ISO C 99 with IEC 60559], @@ -105,3 +115,55 @@ int main (int argc, char *argv[]) fi AC_SUBST([HYPOTL_LIBM]) ]) + +dnl Test whether hypotl() works. +dnl On OpenBSD 5.1/SPARC, +dnl hypotl (2.5541394760659556563446062497337725156L, 7.7893454113437840832487794525518765265L) +dnl has rounding errors that eat up the last 8 to 9 decimal digits. +AC_DEFUN([gl_FUNC_HYPOTL_WORKS], +[ + AC_REQUIRE([AC_PROG_CC]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CACHE_CHECK([whether hypotl works], [gl_cv_func_hypotl_works], + [ + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#include +#include +static long double +my_ldexpl (long double x, int d) +{ + for (; d > 0; d--) + x *= 2.0L; + for (; d < 0; d++) + x *= 0.5L; + return x; +} +volatile long double x; +volatile long double y; +volatile long double z; +int main () +{ + long double err; + + x = 2.5541394760659556563446062497337725156L; + y = 7.7893454113437840832487794525518765265L; + z = hypotl (x, y); + err = z * z - (x * x + y * y); + err = my_ldexpl (err, LDBL_MANT_DIG); + if (err < 0) + err = - err; + if (err > 1000.0L) + return 1; + return 0; +} +]])], + [gl_cv_func_hypotl_works=yes], + [gl_cv_func_hypotl_works=no], + [case "$host_os" in + openbsd*) gl_cv_func_hypotl_works="guessing no";; + *) gl_cv_func_hypotl_works="guessing yes";; + esac + ]) + ]) +]) -- 2.11.0