A Register Allocation Framework for Banked Register Files with Access Constraints

Banked register file has been proposed to reduce die area, power consumption, and access time. Some embedded processors, e.g. Intel’s IXP network processors, adopt this organization. However, they expose some access constraints in ISA, which complicates the design of register allocation. In this paper, we present a register allocation framework for banked register files with access constraints for the IXP network processors. Our approach relies on the estimation of the costs and benefits of assigning a virtual register to a specific bank, as well as that of splitting it into multiple banks via copy instructions. We make the decision of bank assignment or live range splitting based on analysis of these costs and benefits. Compared to previous works, our framework can better balance the register pressure among multiple banks and improve the performance of typical network applications.