1. Apparatus for processing data, said apparatus comprising: a register file having a plurality of registers for storing respective register data values; a cache having a plurality of storage locations for storing respective cache data values corresponding to register data values stored within said register file; a comparator coupled to said register file and to said cache and responsive to a register data value read from said register file and a corresponding cache data value read from said cache to generate a match signal indicating whether said register data value matches said cache data value; and a value selector responsive to said match signal indicating that said register data value does not match said cache data value to determine which of said register data value and said cache data value is correct and to select for output a correct one of said register data value and said cache data value.