Merge changes from new-regalloc-branch

	From Michael Matz  <matz@suse.de>
	* df.c (df_ref_record_1): Move init of loc to safe point.
	Only recurse on interesting things in parallels.
	Handle CLASS_CANNOT_CHANGE_MODE smarter.
	(df_uses_record): Ditto.

	* df.h (DF_REF_MEM_OK): New enum member, used to mark ref's which
	it's already okay to use memory operands in (IE doesn't require
	adding another insn or anything).

From-SVN: r64629