Implicit enumeration of structural changes in circuit optimization

Abstract

We describe an implicit technique for enumerating structural choices in circuit optimization. The restructuring technique relies on the symbolic statements of functional decomposition which explores behavioral equivalence of circuit signals through rewiring and resubstitution. Using rigid, yet practical, formulation a rich variety of restructuring candidates is computed symbolically and applied incrementally to produce circuit changes with predictable structural effects. The restructuring technique is used to obtain much improved delays of the already optimized circuits along with their area savings. It is also applied to analyze benefits of optimizing circuit topology at the early steps of synthesis targeting its routability.