Minimal logic re-synthesis for engineering change

We propose an iterative solution to the problem of logic re-synthesis; we begin with a small region for re-synthesis (selected using some criteria), and iteratively expand that region until a solution is obtained. At each stage, we test if this resynthesizing this region alone can realize the new specification. As a second pass, we trim the region iteratively, so that it becomes minimal in the sense that no subset of the current region can realize the change in functionality. However, not all minimal regions are equivalent in terms of their power, area or delay optimality. To compare two different minimal re-synthesis regions, we use a heuristic evaluation criteria for the acceptability of regions for re-synthesis called sensitivity. We compute the sensitivity (or acceptability for resynthesis) for power. This sensitivity criteria is used to pick nodes in the iterative scheme. An iterative algorithm is given for incremental synthesis that begins with an empty re-synthesis region, and iteratively picks nodes from the rest of the network to add to the region (in order of their sensitivity).