In one embodiment, a renamer comprises a plurality of storage locations
and compare circuitry. Each storage location is assigned to a respective
renameable resource and is configured to store an identifier
corresponding to a youngest instruction operation that writes the
respective renameable resource. Coupled to receive an input representing
one or more retiring instruction identifiers corresponding to instruction
operations that are being retired, the compare circuitry is configured to
detect a match between at least a first identifier in a first storage
location and one of the retiring identifiers. An encoded form of the
identifiers is logically divided into a plurality of fields, and the
input comprises a first plurality of bit vectors. Each of the first
plurality of bit vectors corresponds to a respective field and includes a
bit position for each possible value of the respective field.