>From e5462c3304ef7f373bfb7c6a976dc25730412a7a Mon Sep 17 00:00:00 2001
From: Bruno Haible
Date: Sun, 20 Jan 2019 23:48:18 +0100
Subject: [PATCH 5/6] log10l: Work around inaccurate implementation on NetBSD.
* m4/log10l.m4 (gl_FUNC_LOG10L_WORKS): Add test for a certain accuracy.
* lib/log10l.c: Comment out too simplistic override.
* doc/posix-functions/log10l.texi: Mention the NetBSD bug.
---
ChangeLog | 7 ++++
doc/posix-functions/log10l.texi | 4 ++
lib/log10l.c | 2 +-
m4/log10l.m4 | 87 +++++++++++++++++++++++++++++++++--------
4 files changed, 82 insertions(+), 18 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 98702e2..00516b2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2019-01-20 Bruno Haible
+ log10l: Work around inaccurate implementation on NetBSD.
+ * m4/log10l.m4 (gl_FUNC_LOG10L_WORKS): Add test for a certain accuracy.
+ * lib/log10l.c: Comment out too simplistic override.
+ * doc/posix-functions/log10l.texi: Mention the NetBSD bug.
+
+2019-01-20 Bruno Haible
+
logl: Work around inaccurate implementation on NetBSD.
* m4/logl.m4 (gl_FUNC_LOGL_WORKS): Add test for a certain accuracy.
* lib/logl.c: Comment out unused code.
diff --git a/doc/posix-functions/log10l.texi b/doc/posix-functions/log10l.texi
index b26a249..ac42644 100644
--- a/doc/posix-functions/log10l.texi
+++ b/doc/posix-functions/log10l.texi
@@ -26,6 +26,10 @@ IRIX 6.5.
@item
This function returns an unnormalized positive infinity for a positive infinite argument 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 not fixed by Gnulib:
diff --git a/lib/log10l.c b/lib/log10l.c
index 765d485..4ac6085 100644
--- a/lib/log10l.c
+++ b/lib/log10l.c
@@ -27,7 +27,7 @@ log10l (long double x)
return log10 (x);
}
-#elif HAVE_LOG10L
+#elif 0 /* was: HAVE_LOG10L */
# include
diff --git a/m4/log10l.m4 b/m4/log10l.m4
index af0afaf..80835f6 100644
--- a/m4/log10l.m4
+++ b/m4/log10l.m4
@@ -1,4 +1,4 @@
-# log10l.m4 serial 5
+# log10l.m4 serial 6
dnl Copyright (C) 2011-2019 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -60,6 +60,7 @@ dnl 0xFFF00000000000007FF0000000000000, should be
dnl 0xFFF00000000000000000000000000000.
dnl On AIX 5.1, log10l(-0.0L) is finite if it's not the first log10l call
dnl in the program.
+dnl On NetBSD 8.0, the result is accurate to only 16 digits.
AC_DEFUN([gl_FUNC_LOG10L_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
@@ -68,36 +69,88 @@ AC_DEFUN([gl_FUNC_LOG10L_WORKS],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include
#include
-#ifndef log10l /* for AIX */
+/* 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 log10l /* for AIX */
extern
#ifdef __cplusplus
"C"
#endif
long double log10l (long double);
-#endif
-volatile long double x;
-long double y;
-int main ()
+static long double dummy (long double x) { return 0; }
+volatile long double gx;
+long double gy;
+int main (int argc, char *argv[])
{
+ long double (* volatile my_log10l) (long double) = argc ? log10l : dummy;
+ int result = 0;
/* Dummy call, to trigger the AIX 5.1 bug. */
- x = 0.6L;
- y = log10l (x);
+ gx = 0.6L;
+ gy = log10l (gx);
/* This test fails on AIX 5.1, IRIX 6.5, OSF/1 5.1. */
- x = -0.0L;
- y = log10l (x);
- if (!(y + y == y))
- return 1;
- return 0;
+ {
+ gx = -0.0L;
+ gy = log10l (gx);
+ if (!(gy + gy == gy))
+ result |= 1;
+ }
+ /* 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 = 7.90097792256024576L;
+ long double err = (my_log10l (x) + my_log10l (1.0L / x)) * TWO_LDBL_MANT_DIG;
+ if (!(err >= -100.0L && err <= 100.0L))
+ result |= 2;
+ }
+ return result;
}
]])],
[gl_cv_func_log10l_works=yes],
[gl_cv_func_log10l_works=no],
[case "$host_os" in
- aix* | irix* | osf*) gl_cv_func_log10l_works="guessing no" ;;
- # Guess yes on native Windows.
- mingw*) gl_cv_func_log10l_works="guessing yes" ;;
- *) gl_cv_func_log10l_works="guessing yes" ;;
+ # Guess yes on glibc systems.
+ *-gnu* | gnu*) gl_cv_func_log10l_works="guessing yes" ;;
+ # Guess yes on native Windows.
+ mingw*) gl_cv_func_log10l_works="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_log10l_works="guessing no" ;;
esac
])
])
--
2.7.4