2012-05-25  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/53383
	* doc/invoke.texi: Add a warning for -mpreferred-stack-boundary=3.

	* config/i386/i386.c (ix86_option_override_internal): Allow
	-mpreferred-stack-boundary=3 for 64-bit if SSE is disenabled.

	* config/i386/i386.h (MIN_STACK_BOUNDARY): Set to 64 for 64-bit
	if SSE is disenabled.