c4x.c: Convert to gen_rtx_FOO.

c4x.c: Convert to gen_rtx_FOO.

	* config/c4x/c4x.c:  Convert to gen_rtx_FOO.
	Added ATTRIBUTE_UNUSED to unused function arguments.
	(rc_reg_operand): New predicate.
	(c4x_rptb_insert): New function.
	(c4x_rptb_nop_p): Recognize modified rptb_top pattern.
	(c4x_optimization_options): New function.
	* config/c4x/c4x.md: Convert to gen_rtx_FOO.
	 (decrement_and_branch_on_count): New pattern.
	 (rptb_top): Modified pattern to work with BCT optimization.
	* config/c4x/c4x.h (RC_REG): New register class.
	(rc_reg_operand): Define prototype.
	(IS_RC_REG): New macro.
	(IS_RC_OR_PSEUDO_REG): New macro.
	(IS_RC_OR_PSEUDO_REGNO): New macro.
	(OPTIMIZATION_OPTIONS): Define.

From-SVN: r23037