Comparing structurally different views of a VLSI design

In large VLSI design projects, it is desirable to compare alternate views that use different hierarchies. However, existing techniques either require essentially identical hierarchies (which is sometimes an unacceptable restriction) or must flatten to remove the differences (which may be very costly). A new technique, informed comparison, has neither of these shortcomings. First, hierarchy transformations are applied to reconcile the structures of the views: then a hierarchical base comparison finishes the task. The reconciliation is guided by a small amount of additional design information: the intended relationship between the hierarchies of the views. Some qualities of informed comparison depend on the reconciliation repertoire and the base comparison. Two examples are studied