Optimal spare latch selection for metal-only ecos

Abstract

Various embodiments include: determining boundary vertices for an ECO within a placed netlist based on: a first weight assigned to a gate array distribution; and a second weight assigned to routing congestion, the boundary vertices defining a polygon; implementing the ECO at gate level; estimating slack value for determined boundary vertices; assigning vertex weights to boundary vertices based on the estimated slack values for boundary vertices; calculating a weighted centroid location for the polygon, based on the vertex weights; locating spare latches in the placed netlist; determining a clock domain and a clock gating domain for each located spare latch; assigning a cost function to each located spare latch having a same clock domain and a same clock gating domain as the ECO; ranking each respective cost function for each located spare latch; and selecting the desired spare latch based on the ranking of the each located spare latch.