optab.c (maybe_emit_atomic_exchange): New.

optab.c (maybe_emit_atomic_exchange): New.

2011-11-24  Andrew MacLeod  <amacleod@redhat.com>

	* optab.c (maybe_emit_atomic_exchange): New.  Try to emit an
	atomic_exchange pattern.
	(maybe_emit_sync_lock_test_and_set): New.  Try to emit an exchange
	using __sync_lock_test_and_set.
	(maybe_emit_compare_and_swap_exchange_loop): New. Try to emit an
	exchange using a compare_and_swap loop.
	(expand_sync_lock_test_and_set): New.  Expand sync_lock_test_and_set.
	(expand_atomic_test_and_set): New.  Expand test_and_set operation.
	(expand_atomic_exchange): Use new maybe_emit_* functions.
	(expand_atomic_store): Use new maybe_emit_* functions.
	* builtins.c (expand_builtin_sync_lock_test_and_set): Call
	expand_sync_lock_test_and_set routine.
	(expand_builtin_atomic_exchange): Remove parameter from call.
	(expand_builtin_atomic_clear): Use atomic_clear pattern if present.
	(expand_builtin_atomic_test_and_set): Add target and simply call
	expand_atomic_test_and_set.
	(expand_builtin): Add target to expand_builtin_atomic_test_and_set.
	* expr.h (expand_atomic_exchange): Add parameter.
	(expand_sync_lock_test_and_set): New prototype.
	(expand_atomic_test_and_set, expand_atomic_clear): New prototypes.

From-SVN: r181702