i386.md: Create new [right,left] rotate and right shift patterns to optimize shift by 1...

	* i386.md: Create new [right,left] rotate and right shift
	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.

From-SVN: r34569