-# log1pl.m4 serial 8
+# log1pl.m4 serial 9
dnl Copyright (C) 2012-2021 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
LIBS="$save_LIBS"
if test $ac_cv_func_log1pl = yes; then
LOG1PL_LIBM="$LOG1P_LIBM"
+
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $LOG1PL_LIBM"
+ gl_FUNC_LOG1PL_WORKS
+ LIBS="$save_LIBS"
+ case "$gl_cv_func_log1pl_works" in
+ *yes) ;;
+ *) REPLACE_LOG1PL=1 ;;
+ esac
+
m4_ifdef([gl_FUNC_LOG1PL_IEEE], [
if test $gl_log1pl_required = ieee && test $REPLACE_LOG1PL = 0; then
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
fi
AC_SUBST([LOG1PL_LIBM])
])
+
+dnl Test whether log1pl() works.
+dnl On musl 1.2.2/{arm64,s390x}, the result is accurate to only 16 digits.
+AC_DEFUN([gl_FUNC_LOG1PL_WORKS],
+[
+ AC_REQUIRE([AC_PROG_CC])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether log1pl works], [gl_cv_func_log1pl_works],
+ [
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <float.h>
+#include <math.h>
+/* Override the values of <float.h>, 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 log1pl
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double log1pl (long double);
+static long double dummy (long double x) { return 0; }
+int main (int argc, char *argv[])
+{
+ long double (* volatile my_log1pl) (long double) = argc ? log1pl : dummy;
+ int result = 0;
+ /* This test fails on musl 1.2.2/arm64, musl 1.2.2/s390x. */
+ {
+ 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 y = my_log1pl (x);
+ long double z = my_log1pl (- x / (1.0L + x));
+ long double err = (y + z) * TWO_LDBL_MANT_DIG;
+ if (!(err >= -900.0L && err <= 900.0L))
+ result |= 1;
+ }
+
+ return result;
+}
+]])],
+ [gl_cv_func_log1pl_works=yes],
+ [gl_cv_func_log1pl_works=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu* | gnu*) gl_cv_func_log1pl_works="guessing yes" ;;
+ # Guess no on musl systems.
+ *-musl*) gl_cv_func_log1pl_works="guessing no" ;;
+ # Guess yes on native Windows.
+ mingw*) gl_cv_func_log1pl_works="guessing yes" ;;
+ # If we don't know, obey --enable-cross-guesses.
+ *) gl_cv_func_log1pl_works="$gl_cross_guess_normal" ;;
+ esac
+ ])
+ ])
+])