Method for logic optimization for improving timing and congestion during placement in integrated circuit design

TL;DR: In this paper, different types of logic optimizations are used to help placement relieve congestion, such as selecting faster cells and changing the topology of the circuit to move cells to reduce congestion and enable routing.

Abstract: This invention recognizes the ability of logic optimization to help placement relieve congestion. Different types of logic optimizations are used to help placement relieve congestion. In one type of optimization, the speed of parts of the circuit is improved by selecting faster cells. In another type of optimization, the topology of the circuit is changed such that placement can now move cells, which could not have been moved before, to reduce congestion and thus enable routing. A distinguishing feature of this methodology is that it not only uses the placement information for interconnection delay/area estimates during logic optimization, but also uses logic optimization to aid the physical placement steps by providing support to placement so that the congestion of the circuit is improved. The aim is to avoid getting into a situation where the placed circuit cannot be routed.