From: Bruno Haible Date: Sun, 31 Jan 2021 12:21:24 +0000 (+0100) Subject: remainderl: Work around musl libc bug. X-Git-Tag: v1.0~3101 X-Git-Url: https://gitweb.git.savannah.gnu.org/gitweb/?a=commitdiff_plain;h=4f16dff6417dd406919d873bd6b58f6f4f85b3bd;p=gnulib.git remainderl: Work around musl libc bug. * doc/posix-functions/remainderl.texi: Document musl libc bug. * m4/remainderl.m4 (gl_FUNC_REMAINDERL_WORKS): Add more tests. Update cross compilation guess. --- diff --git a/ChangeLog b/ChangeLog index 1b8fd272f3..be461188c1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2021-01-31 Bruno Haible + + remainderl: Work around musl libc bug. + * doc/posix-functions/remainderl.texi: Document musl libc bug. + * m4/remainderl.m4 (gl_FUNC_REMAINDERL_WORKS): Add more tests. Update + cross compilation guess. + 2021-01-31 Bruno Haible log2l: Work around musl libc bugs. diff --git a/doc/posix-functions/remainderl.texi b/doc/posix-functions/remainderl.texi index e1b439fa5f..1a8f625998 100644 --- a/doc/posix-functions/remainderl.texi +++ b/doc/posix-functions/remainderl.texi @@ -17,6 +17,10 @@ IRIX 6.5. @item This function returns completely wrong values on some platforms: OpenBSD 5.1/SPARC. +@item +This function produces results which are accurate to only 16 digits on some +platforms: +musl libc 1.2.2/arm64, musl libc 1.2.2/s390x. @end itemize Portability problems fixed by Gnulib module @code{remainderl-ieee}: diff --git a/m4/remainderl.m4 b/m4/remainderl.m4 index 395ad2a888..4867f9cc95 100644 --- a/m4/remainderl.m4 +++ b/m4/remainderl.m4 @@ -1,4 +1,4 @@ -# remainderl.m4 serial 12 +# remainderl.m4 serial 13 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, @@ -153,6 +153,7 @@ int main (int argc, char *argv[]) dnl Test whether remainderl() works. dnl It produces completely wrong values on OpenBSD 5.1/SPARC. +dnl On musl 1.2.2/{arm64,s390x}, the result is accurate to only 16 digits. AC_DEFUN([gl_FUNC_REMAINDERL_WORKS], [ AC_REQUIRE([AC_PROG_CC]) @@ -164,33 +165,90 @@ AC_DEFUN([gl_FUNC_REMAINDERL_WORKS], #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 extern #ifdef __cplusplus "C" #endif long double remainderl (long double, long double); -volatile long double x; -volatile long double y; -long double z; -int main () +static long double dummy (long double x, long double y) { return 0; } +volatile long double gx; +volatile long double gy; +long double gz; +int main (int argc, char *argv[]) { + long double (* volatile my_remainderl) (long double, long double) = + argc ? remainderl : dummy; + int result = 0; /* This test fails on OpenBSD 5.1/SPARC. */ - x = 9.245907126L; - y = 3.141592654L; - z = remainderl (x, y); - if (z >= 0.0L) - return 1; - return 0; + { + gx = 9.245907126L; + gy = 3.141592654L; + gz = remainderl (gx, gy); + if (gz >= 0.0L) + 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 = 11.357996098166760874793827872740874983168L; + long double y = 0.486497838502717923110029188864352615388L; + long double z = my_remainderl (x, y) - (x - 23 * y); + long double err = z * TWO_LDBL_MANT_DIG; + if (!(err >= -32.0L && err <= 32.0L)) + result |= 2; + } + return result; } ]])], [gl_cv_func_remainderl_works=yes], [gl_cv_func_remainderl_works=no], [case "$host_os" in - openbsd*) gl_cv_func_remainderl_works="guessing no" ;; - # Guess yes on native Windows. - mingw*) gl_cv_func_remainderl_works="guessing yes" ;; - *) gl_cv_func_remainderl_works="guessing yes" ;; + # Guess yes on glibc systems. + *-gnu* | gnu*) gl_cv_func_remainderl_works="guessing yes" ;; + # Guess no on musl systems. + *-musl*) gl_cv_func_remainderl_works="guessing no" ;; + # Guess no on OpenBSD. + openbsd*) gl_cv_func_remainderl_works="guessing no" ;; + # Guess yes on native Windows. + mingw*) gl_cv_func_remainderl_works="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_remainderl_works="$gl_cross_guess_normal" ;; esac ]) ])