Patent attributes
Methods and apparatuses to automatically determine conditions at hierarchical boundaries of a hierarchical circuit design and to use the determined conditions in hierarchical optimization and verification. In one embodiment, a hierarchical block is optimized and transformed during design synthesis using one or more lemmas at the boundary of the hierarchical block. For example, the lemmas are automatically generated to specify range information for input boundary nodes. The lemmas are also used for the equivalence checker to perform hierarchical equivalence checking. Equivalence of hierarchical blocks is individually checked, in view of the lemmas. Thus, based on the lemmas, optimizations across hierarchical boundaries can be performed, while the hierarchical structure of the design is preserved so that equivalence checking of hierarchical circuit designs can still be based on the equivalence of individual hierarchical blocks.