sh.h (RETURN_ADDR_RTX): Use NULL_RTX instead of 0.

sh.h (RETURN_ADDR_RTX): Use NULL_RTX instead of 0.

	* config/sh/sh.h (RETURN_ADDR_RTX): Use NULL_RTX instead of 0.
	* config/sh/sh.c (INSN_REGMODE_WEIGHT, CURR_REGMODE_PRESSURE):
	Fix line width.
	(dump_table): Use bool type for need_align and have_df variables.
	(find_barrier, sfunc_uses_reg): Use NULL_RTX instead of 0.
	(regs_used): Remove register modifier.
	(barrier_align): Move variables slot, credit, jump_to_next
	into if block above for loop.  Use bool type for jump_to_next.
	(sh_function_arg): Use NULL_RTX instead of 0.

From-SVN: r186366