>From e86cbc4644f41ea3a7b5c898790264e93191a49e Mon Sep 17 00:00:00 2001
From: Bruno Haible
Date: Sun, 20 Jan 2019 21:45:29 +0100
Subject: [PATCH 1/6] exp2l: Work around inaccurate implementation on NetBSD.
* m4/exp2l.m4 (gl_FUNC_EXP2L): Add test for a certain accuracy.
* doc/posix-functions/exp2l.texi: Mention the NetBSD bug.
---
ChangeLog | 6 +++
doc/posix-functions/exp2l.texi | 4 ++
m4/exp2l.m4 | 90 +++++++++++++++++++++++++++++++++++++++++-
3 files changed, 99 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index 6e02f8a..a8c6797 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2019-01-20 Bruno Haible
+ exp2l: Work around inaccurate implementation on NetBSD.
+ * m4/exp2l.m4 (gl_FUNC_EXP2L): Add test for a certain accuracy.
+ * doc/posix-functions/exp2l.texi: Mention the NetBSD bug.
+
+2019-01-20 Bruno Haible
+
floor, floorl: Avoid autoconf warnings.
* modules/floor (configure.ac): Use AC_REQUIRE.
* modules/floorl (configure.ac): Likewise.
diff --git a/doc/posix-functions/exp2l.texi b/doc/posix-functions/exp2l.texi
index a0f7841..672b4de 100644
--- a/doc/posix-functions/exp2l.texi
+++ b/doc/posix-functions/exp2l.texi
@@ -14,6 +14,10 @@ FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, older IRIX
@item
This function is not declared on some platforms:
IRIX 6.5.
address@hidden
+This function produces results which are accurate to only 16 digits on some
+platforms:
+NetBSD 8.0.
@end itemize
Portability problems fixed by Gnulib module @code{exp2l-ieee}:
diff --git a/m4/exp2l.m4 b/m4/exp2l.m4
index 20630cc..8a065d9 100644
--- a/m4/exp2l.m4
+++ b/m4/exp2l.m4
@@ -1,4 +1,4 @@
-# exp2l.m4 serial 6
+# exp2l.m4 serial 7
dnl Copyright (C) 2010-2019 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -26,6 +26,94 @@ AC_DEFUN([gl_FUNC_EXP2L],
dnl Also check whether it's declared.
dnl IRIX 6.5 has exp2l() in libm but doesn't declare it in .
AC_CHECK_DECL([exp2l], , [HAVE_DECL_EXP2L=0], [[#include ]])
+ if test $REPLACE_EXP2L = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether exp2l works],
+ [gl_cv_func_exp2l_works],
+ [
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $EXP2L_LIBM"
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include
+#include
+/* Override the values of , like done in float.in.h. */
+#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
+# undef LDBL_MANT_DIG
+# define LDBL_MANT_DIG 64
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP (-16381)
+# undef LDBL_MAX_EXP
+# define LDBL_MAX_EXP 16384
+#endif
+#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
+# undef LDBL_MANT_DIG
+# define LDBL_MANT_DIG 64
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP (-16381)
+# undef LDBL_MAX_EXP
+# define LDBL_MAX_EXP 16384
+#endif
+#if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP DBL_MIN_EXP
+#endif
+#if defined __sgi && (LDBL_MANT_DIG >= 106)
+# undef LDBL_MANT_DIG
+# define LDBL_MANT_DIG 106
+# if defined __GNUC__
+# undef LDBL_MIN_EXP
+# define LDBL_MIN_EXP DBL_MIN_EXP
+# endif
+#endif
+#undef exp2l
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double exp2l (long double);
+static long double dummy (long double x) { return 0; }
+int main (int argc, char *argv[])
+{
+ long double (* volatile my_exp2l) (long double) = argc ? exp2l : dummy;
+ int result = 0;
+ /* This test fails on NetBSD 8.0. */
+ {
+ const long double TWO_LDBL_MANT_DIG = /* 2^LDBL_MANT_DIG */
+ (long double) (1U << ((LDBL_MANT_DIG - 1) / 5))
+ * (long double) (1U << ((LDBL_MANT_DIG - 1 + 1) / 5))
+ * (long double) (1U << ((LDBL_MANT_DIG - 1 + 2) / 5))
+ * (long double) (1U << ((LDBL_MANT_DIG - 1 + 3) / 5))
+ * (long double) (1U << ((LDBL_MANT_DIG - 1 + 4) / 5));
+ long double x = 11.358L;
+ long double err = (my_exp2l (x) * my_exp2l (- x) - 1.0L) * TWO_LDBL_MANT_DIG;
+ if (!(err >= -100.0L && err <= 100.0L))
+ result |= 1;
+ }
+ return result;
+}
+ ]])],
+ [gl_cv_func_exp2l_works=yes],
+ [gl_cv_func_exp2l_works=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu* | gnu*) gl_cv_func_exp2l_works="guessing yes" ;;
+ # Guess yes on native Windows.
+ mingw*) gl_cv_func_exp2l_works="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_exp2l_works="guessing no" ;;
+ esac
+ ])
+ LIBS="$save_LIBS"
+ ])
+ case "$gl_cv_func_exp2l_works" in
+ *yes) ;;
+ *) REPLACE_EXP2L=1 ;;
+ esac
+ fi
m4_ifdef([gl_FUNC_EXP2L_IEEE], [
if test $gl_exp2l_required = ieee && test $REPLACE_EXP2L = 0; then
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
--
2.7.4