diff options
| -rwxr-xr-x | configure | 92 | ||||
| -rw-r--r-- | configure.in | 38 | ||||
| -rw-r--r-- | pyconfig.h.in | 3 |
3 files changed, 131 insertions, 2 deletions
@@ -1,5 +1,5 @@ #! /bin/sh -# From configure.in Revision: 67463 . +# From configure.in Revision: 68292 . # Guess values for system-dependent variables and create Makefiles. # Generated by GNU Autoconf 2.61 for python 2.7. # @@ -2256,7 +2256,7 @@ echo $ECHO_N "checking for --without-gcc... $ECHO_C" >&6; } if test "${with_gcc+set}" = set; then withval=$with_gcc; case $withval in - no) CC=cc + no) CC=${CC:-cc} without_gcc=yes;; yes) CC=gcc without_gcc=no;; @@ -21523,6 +21523,94 @@ fi LIBS_SAVE=$LIBS LIBS="$LIBS $LIBM" +# Detect whether system arithmetic is subject to x87-style double +# rounding issues. The result of this test has little meaning on non +# IEEE 754 platforms. On IEEE 754, test should return 1 if rounding +# mode is round-to-nearest and double rounding issues are present, and +# 0 otherwise. See http://bugs.python.org/issue2937 for more info. +{ echo "$as_me:$LINENO: checking for x87-style double rounding" >&5 +echo $ECHO_N "checking for x87-style double rounding... $ECHO_C" >&6; } +if test "${ac_cv_x87_double_rounding+set}" = set; then + echo $ECHO_N "(cached) $ECHO_C" >&6 +else + +if test "$cross_compiling" = yes; then + ac_cv_x87_double_rounding=no +else + cat >conftest.$ac_ext <<_ACEOF +/* confdefs.h. */ +_ACEOF +cat confdefs.h >>conftest.$ac_ext +cat >>conftest.$ac_ext <<_ACEOF +/* end confdefs.h. */ + +#include <stdlib.h> +#include <math.h> +int main() { + volatile double x, y, z; + /* 1./(1-2**-53) -> 1+2**-52 (correct), 1.0 (double rounding) */ + x = 0.99999999999999989; /* 1-2**-53 */ + y = 1./x; + if (y != 1.) + exit(0); + /* 1e16+2.99999 -> 1e16+2. (correct), 1e16+4. (double rounding) */ + x = 1e16; + y = 2.99999; + z = x + y; + if (z != 1e16+4.) + exit(0); + /* both tests show evidence of double rounding */ + exit(1); +} + +_ACEOF +rm -f conftest$ac_exeext +if { (ac_try="$ac_link" +case "(($ac_try" in + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;; + *) ac_try_echo=$ac_try;; +esac +eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5 + (eval "$ac_link") 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); } && { ac_try='./conftest$ac_exeext' + { (case "(($ac_try" in + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;; + *) ac_try_echo=$ac_try;; +esac +eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5 + (eval "$ac_try") 2>&5 + ac_status=$? + echo "$as_me:$LINENO: \$? = $ac_status" >&5 + (exit $ac_status); }; }; then + ac_cv_x87_double_rounding=no +else + echo "$as_me: program exited with status $ac_status" >&5 +echo "$as_me: failed program was:" >&5 +sed 's/^/| /' conftest.$ac_ext >&5 + +( exit $ac_status ) +ac_cv_x87_double_rounding=yes +fi +rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext +fi + + +fi + +{ echo "$as_me:$LINENO: result: $ac_cv_x87_double_rounding" >&5 +echo "${ECHO_T}$ac_cv_x87_double_rounding" >&6; } +if test "$ac_cv_x87_double_rounding" = yes +then + +cat >>confdefs.h <<\_ACEOF +#define X87_DOUBLE_ROUNDING 1 +_ACEOF + +fi + + # On FreeBSD 6.2, it appears that tanh(-0.) returns 0. instead of # -0. on some architectures. { echo "$as_me:$LINENO: checking whether tanh preserves the sign of zero" >&5 diff --git a/configure.in b/configure.in index 7136d78..ea8727c 100644 --- a/configure.in +++ b/configure.in @@ -3143,6 +3143,44 @@ fi], LIBS_SAVE=$LIBS LIBS="$LIBS $LIBM" +# Detect whether system arithmetic is subject to x87-style double +# rounding issues. The result of this test has little meaning on non +# IEEE 754 platforms. On IEEE 754, test should return 1 if rounding +# mode is round-to-nearest and double rounding issues are present, and +# 0 otherwise. See http://bugs.python.org/issue2937 for more info. +AC_MSG_CHECKING(for x87-style double rounding) +AC_CACHE_VAL(ac_cv_x87_double_rounding, [ +AC_TRY_RUN([ +#include <stdlib.h> +#include <math.h> +int main() { + volatile double x, y, z; + /* 1./(1-2**-53) -> 1+2**-52 (correct), 1.0 (double rounding) */ + x = 0.99999999999999989; /* 1-2**-53 */ + y = 1./x; + if (y != 1.) + exit(0); + /* 1e16+2.99999 -> 1e16+2. (correct), 1e16+4. (double rounding) */ + x = 1e16; + y = 2.99999; + z = x + y; + if (z != 1e16+4.) + exit(0); + /* both tests show evidence of double rounding */ + exit(1); +} +], +ac_cv_x87_double_rounding=no, +ac_cv_x87_double_rounding=yes, +ac_cv_x87_double_rounding=no)]) +AC_MSG_RESULT($ac_cv_x87_double_rounding) +if test "$ac_cv_x87_double_rounding" = yes +then + AC_DEFINE(X87_DOUBLE_ROUNDING, 1, + [Define if arithmetic is subject to x87-style double rounding issue]) +fi + + # On FreeBSD 6.2, it appears that tanh(-0.) returns 0. instead of # -0. on some architectures. AC_MSG_CHECKING(whether tanh preserves the sign of zero) diff --git a/pyconfig.h.in b/pyconfig.h.in index 4075d14..e3fb0a5 100644 --- a/pyconfig.h.in +++ b/pyconfig.h.in @@ -983,6 +983,9 @@ first (like Motorola and SPARC, unlike Intel and VAX). */ #undef WORDS_BIGENDIAN +/* Define if arithmetic is subject to x87-style double rounding issue */ +#undef X87_DOUBLE_ROUNDING + /* Define to 1 if on AIX 3. System headers sometimes define this. We just want to avoid a redefinition error message. */ |