Mercurial > gnulib
view m4/truncl.m4 @ 39912:062361de7628
floor, ceil, trunc, truncf, truncl: Defeat GCC optimizations.
* m4/floor.m4 (gl_FUNC_FLOOR_LIBS): Use 'floor' also through a function
pointer.
* m4/ceil.m4 (gl_FUNC_CEIL_LIBS): Use 'ceil' also through a function
pointer.
* m4/trunc.m4 (gl_FUNC_TRUNC): Use 'trunc' also through a function
pointer.
* m4/truncf.m4 (gl_FUNC_TRUNCF): Use 'truncf' also through a function
pointer.
* m4/truncl.m4 (gl_FUNC_TRUNCL): Use 'truncl' also through a function
pointer.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Sun, 14 Oct 2018 09:27:21 +0200 |
parents | 10eb9086bea0 |
children | b06060465f09 |
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# truncl.m4 serial 14 dnl Copyright (C) 2007-2008, 2010-2018 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. AC_DEFUN([gl_FUNC_TRUNCL], [ m4_divert_text([DEFAULTS], [gl_truncl_required=plain]) AC_REQUIRE([gl_MATH_H_DEFAULTS]) AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE]) AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles dnl Persuade glibc <math.h> to declare truncl(). AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) dnl Test whether truncl() is declared. AC_CHECK_DECLS([truncl], , , [[#include <math.h>]]) if test "$ac_cv_have_decl_truncl" = yes; then dnl Test whether truncl() can be used without libm. TRUNCL_LIBM=? AC_LINK_IFELSE( [AC_LANG_PROGRAM( [[#ifndef __NO_MATH_INLINES # define __NO_MATH_INLINES 1 /* for glibc */ #endif #include <math.h> long double (*funcptr) (long double) = truncl; long double x;]], [[x = funcptr(x) + truncl(x);]])], [TRUNCL_LIBM=]) if test "$TRUNCL_LIBM" = "?"; then save_LIBS="$LIBS" LIBS="$LIBS -lm" AC_LINK_IFELSE( [AC_LANG_PROGRAM( [[#ifndef __NO_MATH_INLINES # define __NO_MATH_INLINES 1 /* for glibc */ #endif #include <math.h> long double (*funcptr) (long double) = truncl; long double x;]], [[x = funcptr(x) + truncl(x);]])], [TRUNCL_LIBM="-lm"]) LIBS="$save_LIBS" fi if test "$TRUNCL_LIBM" = "?"; then TRUNCL_LIBM= fi dnl Test whether truncl() works. It crashes on OSF/1 4.0d. save_LIBS="$LIBS" LIBS="$LIBS $TRUNCL_LIBM" AC_CACHE_CHECK([whether truncl works], [gl_cv_func_truncl_works], [ AC_RUN_IFELSE( [AC_LANG_SOURCE([[ #include <math.h> long double x; int main() { x = truncl (0.0L); return 0; }]])], [gl_cv_func_truncl_works=yes], [gl_cv_func_truncl_works=no], [case "$host_os" in osf4*) gl_cv_func_truncl_works="guessing no" ;; # Guess yes on native Windows. mingw*) gl_cv_func_truncl_works="guessing yes" ;; *) gl_cv_func_truncl_works="guessing yes" ;; esac ]) ]) LIBS="$save_LIBS" case "$gl_cv_func_truncl_works" in *yes) ;; *) REPLACE_TRUNCL=1 ;; esac m4_ifdef([gl_FUNC_TRUNCL_IEEE], [ if test $gl_truncl_required = ieee && test $REPLACE_TRUNCL = 0; then AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether truncl works according to ISO C 99 with IEC 60559], [gl_cv_func_truncl_ieee], [ save_LIBS="$LIBS" LIBS="$LIBS $TRUNCL_LIBM" AC_RUN_IFELSE( [AC_LANG_SOURCE([[ #ifndef __NO_MATH_INLINES # define __NO_MATH_INLINES 1 /* for glibc */ #endif #include <math.h> ]gl_LONG_DOUBLE_MINUS_ZERO_CODE[ ]gl_LONG_DOUBLE_SIGNBIT_CODE[ static long double dummy (long double f) { return 0; } int main (int argc, char *argv[]) { long double (*my_truncl) (long double) = argc ? truncl : dummy; /* Test whether truncl (-0.3L) is -0.0L. */ if (signbitl (minus_zerol) && !signbitl (my_truncl (-0.3L))) return 1; return 0; } ]])], [gl_cv_func_truncl_ieee=yes], [gl_cv_func_truncl_ieee=no], [case "$host_os" in # Guess yes on glibc systems. *-gnu* | gnu*) gl_cv_func_truncl_ieee="guessing yes" ;; # Guess yes on native Windows. mingw*) gl_cv_func_truncl_ieee="guessing yes" ;; # If we don't know, assume the worst. *) gl_cv_func_truncl_ieee="guessing no" ;; esac ]) LIBS="$save_LIBS" ]) case "$gl_cv_func_truncl_ieee" in *yes) ;; *) REPLACE_TRUNCL=1 ;; esac fi ]) else HAVE_DECL_TRUNCL=0 fi if test $HAVE_DECL_TRUNCL = 0 || test $REPLACE_TRUNCL = 1; then dnl Find libraries needed to link lib/truncl.c. if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then AC_REQUIRE([gl_FUNC_TRUNC]) TRUNCL_LIBM="$TRUNC_LIBM" else TRUNCL_LIBM= fi fi AC_SUBST([TRUNCL_LIBM]) ])