1. A computer program product for performing processing associated with transactional execution in a computing environment, the computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: obtaining, by a processor, an instruction to be executed as part of a transaction, the transaction effectively delaying committing transactional stores to main memory until completion of a selected transaction; computing one or more effective controls from one or more controls set by one or more transaction begin instructions; determining by the processor whether the instruction is a selectively restricted instruction that is prohibited from execution within the transaction, the determining being based on the computed one or more effective controls; and performing processing associated with the instruction based on whether the instruction is selectively restricted.