Optimization when extensions don't provide handlers

Hi I have seen that the php-src uses some flags like ZEND_EXTENSIONS_HAVE_OP_ARRAY_HANDLER to optimise the code so that the loop that calls the op array handler is not called if no extension has set up an op array handler I wonder why this has not been done for the statement_handler, fcall_begin_handler and fcall_end_handler. This could be used to provide an optimised execution when no extension sets up a handler for these extension points Interested to know if there is a technical reason for this Cheers Carlos