1. An apparatus for processing data under control of a sequence of program instructions, said apparatus comprising: an instruction decoder for decoding said instructions to generate decoded instructions, said program instructions including at least one instruction having a plurality of alternative outcomes, said alternative outcomes including at least a first outcome that is independent of at least one operand and a second outcome that is dependent on said at least one operand, said at least one operand being generated by a preceding instruction of said sequence of program instructions; instruction issuing circuitry for issuing said decoded instructions for execution, said instruction issuing circuitry being configured to issue a decoded instruction corresponding to said at least one instruction independently of when said at least one operand is generated by said preceding instruction; instruction execution circuitry for executing said decoded instructions issued by said instruction issuing circuitry; and recovery circuitry for performing a recovery operation in the event that said second outcome is executed for said at least one instruction and said at least one operand has not been generated by said preceding instruction when said decoded instruction corresponding to said at least one instruction is to be executed by said instruction execution circuitry.