The SSE2 detection and enabling could potentially cause
problems for binary distributions of Python in situations
where the build machine has SSE2 but the target machine
does not.
Therefore, don't enable SSE2 instructions automatically on x86.
diff --git a/configure b/configure
index de5c354..e988b85 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
#! /bin/sh
-# From configure.in Revision: 71663 .
+# From configure.in Revision: 71704 .
# Guess values for system-dependent variables and create Makefiles.
# Generated by GNU Autoconf 2.61 for python 3.1.
#
@@ -21827,174 +21827,21 @@
fi
-# David Gay's code in Python/dtoa.c requires that the FPU uses 53-bit
+# The short float repr introduced in Python 3.1 requires the
+# correctly-rounded string <-> double conversion functions in
+# Python/dtoa.c, which in turn require that the FPU uses 53-bit
# rounding; this is a particular problem on x86, where the x87 FPU has
# a default rounding precision of 64 bits. For gcc/x86, we try to fix
-# this by:
-#
-# (1) using the SSE2 instruction set when available (it usually is
-# on modern machines)
-# (2) using inline assembler to get and set the x87 FPU control word
-# otherwise.
-#
-# On AMD64 (aka x86-64), gcc automatically enables use of SSE2
-# instructions, so we don't bother trying to detect.
+# this by using inline assembler to get and set the x87 FPU control
+# word.
if test "$GCC" = yes && test -n "`$CC -dM -E - </dev/null | grep i386`"
then
- # determine whether we're already using the SSE2 instruction set for math
- # (e.g., this is true by default on OS X/x86)
- { echo "$as_me:$LINENO: checking whether SSE2 instructions are already enabled for math" >&5
-echo $ECHO_N "checking whether SSE2 instructions are already enabled for math... $ECHO_C" >&6; }
- if test -n "`$CC -dM -E - </dev/null | grep __SSE2_MATH__`"
- then
- ac_sse2_enabled=yes
- else
- ac_sse2_enabled=no
- fi
- { echo "$as_me:$LINENO: result: $ac_sse2_enabled" >&5
-echo "${ECHO_T}$ac_sse2_enabled" >&6; }
-
- # if we're not using SSE2 already, we need to either enable it
- # (when available), or use inline assembler to get and set the
- # 387 control word.
- if test $ac_sse2_enabled = no
- then
- # Check cpuid for SSE2 availability. Bits 25 and 26 of edx tell
- # us about SSE and SSE2 respectively.
- { echo "$as_me:$LINENO: checking whether SSE2 instructions are available on this CPU" >&5
-echo $ECHO_N "checking whether SSE2 instructions are available on this CPU... $ECHO_C" >&6; }
- if test "$cross_compiling" = yes; then
- ac_cv_cpu_has_sse2=no
-else
- cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h. */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h. */
-
- int main() {
- unsigned int ax, bx, cx, dx, func;
- func = 1U;
- __asm__ __volatile__ (
- "pushl %%ebx\n\t" /* don't clobber ebx */
- "cpuid\n\t"
- "movl %%ebx, %1\n\t"
- "popl %%ebx"
- : "=a" (ax), "=r" (bx), "=c" (cx), "=d" (dx)
- : "a" (func)
- : "cc" );
- if ((dx & (1U << 25)) && (dx & (1U << 26)))
- return 0;
- else
- return 1;
- }
-
-_ACEOF
-rm -f conftest$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 $ac_status); }; }; then
- ac_cv_cpu_has_sse2=yes
-else
- echo "$as_me: program exited with status $ac_status" >&5
-echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-( exit $ac_status )
-ac_cv_cpu_has_sse2=no
-fi
-rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
-fi
-
-
- { echo "$as_me:$LINENO: result: $ac_cv_cpu_has_sse2" >&5
-echo "${ECHO_T}$ac_cv_cpu_has_sse2" >&6; }
-
- # determine whether gcc accepts options to turn on SSE2
- { echo "$as_me:$LINENO: checking whether $CC accepts -msse2 -mfpmath=sse" >&5
-echo $ECHO_N "checking whether $CC accepts -msse2 -mfpmath=sse... $ECHO_C" >&6; }
- ac_save_cc="$CC"
- CC="$CC -msse2 -mfpmath=sse"
- if test "$cross_compiling" = yes; then
- ac_cv_msse2_ok=no
-else
- cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h. */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h. */
-int main() { return 0; }
-_ACEOF
-rm -f conftest$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 $ac_status); }; }; then
- ac_cv_msse2_ok=yes
-else
- echo "$as_me: program exited with status $ac_status" >&5
-echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-( exit $ac_status )
-ac_cv_msse2_ok=no
-fi
-rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
-fi
-
-
- CC="$ac_save_cc"
- { echo "$as_me:$LINENO: result: $ac_cv_msse2_ok" >&5
-echo "${ECHO_T}$ac_cv_msse2_ok" >&6; }
-
- if test $ac_cv_cpu_has_sse2 = yes && test $ac_cv_msse2_ok = yes
- then
- BASECFLAGS="$BASECFLAGS -msse2 -mfpmath=sse"
- else
- # SSE2 doesn't appear to be available. Check that it's okay
- # to use gcc inline assembler to get and set x87 control word
-
-cat >>confdefs.h <<\_ACEOF
-#define USING_X87_FPU 1
-_ACEOF
-
- { echo "$as_me:$LINENO: checking whether we can use gcc inline assembler to get and set x87 control word" >&5
+ # Check that it's okay to use gcc inline assembler to get and set
+ # x87 control word
+ { echo "$as_me:$LINENO: checking whether we can use gcc inline assembler to get and set x87 control word" >&5
echo $ECHO_N "checking whether we can use gcc inline assembler to get and set x87 control word... $ECHO_C" >&6; }
- cat >conftest.$ac_ext <<_ACEOF
+ cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
@@ -22005,9 +21852,9 @@
main ()
{
- unsigned short cw;
- __asm__ __volatile__ ("fnstcw %0" : "=m" (cw));
- __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
+ unsigned short cw;
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (cw));
+ __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
;
return 0;
@@ -22039,17 +21886,15 @@
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
- { echo "$as_me:$LINENO: result: $have_gcc_asm_for_x87" >&5
+ { echo "$as_me:$LINENO: result: $have_gcc_asm_for_x87" >&5
echo "${ECHO_T}$have_gcc_asm_for_x87" >&6; }
- if test "$have_gcc_asm_for_x87" = yes
- then
+ if test "$have_gcc_asm_for_x87" = yes
+ then
cat >>confdefs.h <<\_ACEOF
#define HAVE_GCC_ASM_FOR_X87 1
_ACEOF
- fi
- fi
fi
fi