1. A method, in a data processing system comprising at least one processor and at least one memory, for pruning a layer trait library for use in wire routing in an integrated circuit design process, comprising the following operations performed by the data processing system: receiving a plurality of wirecodes and a metal stack definition; generating a verbose layer trait library based on all possible combinations of the wirecodes and layers of the metal stack definition; generating a pruned layer trait library by pruning the verbose layer trait library to remove redundant layer traits from the verbose layer trait library; and storing the pruned layer trait library for performing wire routing of an integrated circuit design, wherein generating the pruned layer trait library comprises: pruning the verbose layer trait library to remove redundant layer traits to generate a first pruned layer trait library; performing clustering of layer traits in the first pruned layer trait library; and pruning the first layer trait library based on the clustering of layer traits in the first pruned layer trait library to generate a second pruned layer trait library.