* simplify-rtx.c (simplify_subreg): Break out from ...
	* combine.c (combine_splify_rtx) ... here and ...
	* recog.c (validate_replace_rtx_1): ... here;
	* rtl.h (subreg_lowpart_parts_p, simplify_subreg): Declare.
	* emit-rtl.c (subreg_lowpart_parts_p): Break out from ...
	(subreg_lowpart_p): ... here.

From-SVN: r42199