A data processing apparatus has control circuitry for detecting whether a current micro-operation to be processed by processing circuitry is for the same data processing operation and specifies the same at least one operand as the last valid micro-operation processed by the processing circuitry. If so, then the control circuitry prevents the processing circuitry processing the current micro-operation so that an output register is not updated in response to the current micro-operation, and outputs the current value stored in the output register as the result of the current micro-operation. This allows power consumption to be reduced or performance to be improved by not repeating the same computation.