patterns to optimize shift by 1 bit for certain ia32 processors.
	Update patterns which perform left shifts to optimize shift by
	1 bit for certain ia32 processors.
	* i386.c (const_int_1_operand): New predicate.
	* i386.h (PREDICATE_CODES): Handle const_int_1_operand.
	* i386-protos.h (const_int_1_operand): Prototype.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@34569 138bc75d-0d04-0410-961f-82ee72b054a4