A method and apparatus for dynamic optimization of strong atomicity barriers is herein described. During runtime compilation, code including non-transactional memory accesses that are to conflict with transactional memory accesses is patched to insert transactional barriers at the conflicting non-transactional memory accesses to ensure isolation and strong atomicity. However, barriers are omitted or removed from non-transactional memory accesses that do not conflict with transactional memory accesses to reduce barrier execution overhead.