* cse.c (fold_rtx): Use simplify_subreg.

	* simplify-rtx.c (simplify_replace_rtx): Use simplify_gen_subreg.
	(simplify_gen_subreg): New.
	(simplify_rtx): Use simplify_subreg.
	* rtl.h (simplify_gen_subreg): Declare.

From-SVN: r42221