diff options
Diffstat (limited to 'm4/log2l.m4')
-rw-r--r-- | m4/log2l.m4 | 109 |
1 files changed, 90 insertions, 19 deletions
diff --git a/m4/log2l.m4 b/m4/log2l.m4 index 47765434fe..31d5432664 100644 --- a/m4/log2l.m4 +++ b/m4/log2l.m4 @@ -1,5 +1,5 @@ -# log2l.m4 serial 2 -dnl Copyright (C) 2010-2021 Free Software Foundation, Inc. +# log2l.m4 serial 8 +dnl Copyright (C) 2010-2024 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -15,10 +15,10 @@ AC_DEFUN([gl_FUNC_LOG2L], dnl Test whether log2l() exists. Assume that log2l(), if it exists, is dnl defined in the same library as log2(). - save_LIBS="$LIBS" + saved_LIBS="$LIBS" LIBS="$LIBS $LOG2_LIBM" - AC_CHECK_FUNCS([log2l]) - LIBS="$save_LIBS" + gl_CHECK_FUNCS_ANDROID([log2l], [[#include <math.h>]]) + LIBS="$saved_LIBS" if test $ac_cv_func_log2l = yes; then LOG2L_LIBM="$LOG2_LIBM" HAVE_LOG2L=1 @@ -26,10 +26,10 @@ AC_DEFUN([gl_FUNC_LOG2L], dnl IRIX 6.5 has log2l() in libm but doesn't declare it in <math.h>. AC_CHECK_DECL([log2l], , [HAVE_DECL_LOG2L=0], [[#include <math.h>]]) - save_LIBS="$LIBS" + saved_LIBS="$LIBS" LIBS="$LIBS $LOG2L_LIBM" gl_FUNC_LOG2L_WORKS - LIBS="$save_LIBS" + LIBS="$saved_LIBS" case "$gl_cv_func_log2l_works" in *yes) ;; *) REPLACE_LOG2L=1 ;; @@ -37,6 +37,9 @@ AC_DEFUN([gl_FUNC_LOG2L], else HAVE_LOG2L=0 HAVE_DECL_LOG2L=0 + case "$gl_cv_onwards_func_log2l" in + future*) REPLACE_LOG2L=1 ;; + esac fi if test $HAVE_LOG2L = 0 || test $REPLACE_LOG2L = 1; then dnl Find libraries needed to link lib/log2l.c. @@ -69,6 +72,7 @@ AC_DEFUN([gl_FUNC_LOG2L], dnl Test whether log2l() works. dnl On OSF/1 5.1, log2l(-0.0) is NaN. +dnl On musl 1.2.2/{arm64,s390x}, the result is accurate to only 16 digits. AC_DEFUN([gl_FUNC_LOG2L_WORKS], [ AC_REQUIRE([AC_PROG_CC]) @@ -77,7 +81,40 @@ AC_DEFUN([gl_FUNC_LOG2L_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 #ifndef log2l /* for AIX */ extern #ifdef __cplusplus @@ -85,25 +122,59 @@ extern #endif long double log2l (long double); #endif -volatile long double x; -volatile long double y; -int main () +static long double dummy (long double x) { return 0; } +volatile long double gx; +volatile long double gy; +int main (int argc, char *argv[]) { + long double (* volatile my_log2l) (long double) = argc ? log2l : dummy; + int result = 0; /* This test fails on OSF/1 5.1. */ - x = -0.0L; - y = log2l (x); - if (!(y + y == y)) - return 1; - return 0; + { + gx = -0.0L; + gy = my_log2l (gx); + if (!(gy + gy == gy)) + result |= 1; + } + /* 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_log2l (x); + long double z = my_log2l (1.0L / x); + long double err = (y + z) * TWO_LDBL_MANT_DIG; + if (!(err >= -10000.0L && err <= 10000.0L)) + result |= 2; + } + /* This test fails on musl 1.2.2/arm64, musl 1.2.2/s390x. */ + if (DBL_MAX_EXP < LDBL_MAX_EXP) + { + long double x = ldexpl (1.0L, DBL_MAX_EXP); /* finite! */ + long double y = my_log2l (x); + if (y > 0 && y + y == y) /* infinite? */ + result |= 4; + } + return result; } ]])], [gl_cv_func_log2l_works=yes], [gl_cv_func_log2l_works=no], [case "$host_os" in - osf*) gl_cv_func_log2l_works="guessing no" ;; - # Guess yes on native Windows. - mingw*) gl_cv_func_log2l_works="guessing yes" ;; - *) gl_cv_func_log2l_works="guessing yes" ;; + # Guess yes on glibc systems. + *-gnu* | gnu*) gl_cv_func_log2l_works="guessing yes" ;; + # Guess no on musl systems. + *-musl* | midipix*) gl_cv_func_log2l_works="guessing no" ;; + # Guess no on OSF/1. + osf*) gl_cv_func_log2l_works="guessing no" ;; + # Guess yes on native Windows. + mingw* | windows*) gl_cv_func_log2l_works="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_log2l_works="$gl_cross_guess_normal" ;; esac ]) ]) |