1. A method of determining whether a first graphics processing unit (GPU) program may be combined with a second GPU program for processing, the method comprising the steps of: checking a cache; and if the cache has no information regarding a combination of a first graphics processing unit (GPU) program with a second GPU program, analyzing said programs to determine if a combination of the programs is possible; if the cache indicates that the combination is possible, retrieving and using a result as indicated by said cache; if the cache indicates that a combination is not possible, not analyzing said programs for possibility of combining.