builtins.c (expand_builtin_atomic_compare_exchange): Pass old value operand as MEM to expand_atomic_compare_and_swap.

	* builtins.c (expand_builtin_atomic_compare_exchange): Pass old
	value operand as MEM to expand_atomic_compare_and_swap.

	* config/s390/s390.md ("atomic_compare_and_swap<mode>"): Accept
	nonimmediate_operand for old value; generate load and store if
	needed.
	* config/s390/s390.c (s390_expand_cs_hqi): Accept any operand
	as vtarget.

From-SVN: r190236