optabs.c (expand_binop): Tighten conditions for doubleword expansions.

optabs.c (expand_binop): Tighten conditions for doubleword expansions.

	* optabs.c (expand_binop): Tighten conditions for doubleword
	expansions.
	(widen_bswap): Assert that mode bitsize and precision are the
	same.
	* stor-layout.c (get_best_mode): Skip modes that have lower
	precision than bitsize.
	* recog.c (simplify_while_replacing): Assert that bitsize and
	precision are the same.

From-SVN: r176040