Something in Dmitry's attribute RFC caught my attention. There is an example implying inline functions indicated by an attribute.
I know that was only a potential use case for an extension. But it made me wonder how much that could improve PHPs performance if we actually had it. As I understand it, the process by which the call stack is updated and scope changed, is quite expensive. And from tests I can see that function calls do actually add a not insignificant overhead to intensive repetitive tasks. So how difficult would it be to get the engine to determine if an inline is feasible, then skip the fcall init, and dump the a functions opcode emits directly into the current scope?
