* config/h8300/h8300-protos.h: Add a prototype for
	h8300_shift_needs_scratch_p.
	* config/h8300/h8300.c (h8300_shift_needs_scratch_p): New.
	* config/h8300/h8300.h (OK_FOR_R): New.
	(OK_FOR_S): Likewise.
	(OK_FOR_T): Likewise.
	(EXTRA_CONSTRAINT): Call OK_FOR_R, OK_FOR_S, and OK_FOR_T.
	* config/h8300/h8300.md (anonymous shift patterns): Use
	constraints R, S, and T.

From-SVN: r54143