PR middle-end/66867
	* builtins.c (expand_ifn_atomic_compare_exchange_into_call,
	expand_ifn_atomic_compare_exchange): New functions.
	* internal-fn.c (expand_ATOMIC_COMPARE_EXCHANGE): New function.
	* tree.h (build_call_expr_internal_loc): Rename to ...
	(build_call_expr_internal_loc_array): ... this.  Fix up type of
	last argument.
	* internal-fn.def (ATOMIC_COMPARE_EXCHANGE): New internal fn.
	* predict.c (expr_expected_value_1): Handle IMAGPART_EXPR of
	ATOMIC_COMPARE_EXCHANGE result.
	* builtins.h (expand_ifn_atomic_compare_exchange): New prototype.
	* gimple-fold.h (optimize_atomic_compare_exchange_p,
	fold_builtin_atomic_compare_exchange): New prototypes.
	* gimple-fold.c (optimize_atomic_compare_exchange_p,
	fold_builtin_atomic_compare_exchange): New functions..
	* tree-ssa.c (execute_update_addresses_taken): If
	optimize_atomic_compare_exchange_p, ignore &var in 2nd argument
	of call when finding addressable vars, and if such var becomes
	non-addressable, call fold_builtin_atomic_compare_exchange.

From-SVN: r237814