Abstract: Register allocation has become one of the most important optimization techniques for compiler for that registers are limited and valuable resources in hardware architecture of computer.One of the key factors affecting the results of register allocation is the access and storage costs incurred from spilling signed registers.For DSP architectures with two classes of general-purpose registers,this paper proposed a complementary utilization strategy between the registers and a corresponding register spilling optimization algorithm on the basis of graph coloring register allocation method.Through distinguishing the interference between candidates of the same register class from those of different register classes,an undirected graph is built by improving the analysis for variables’ live ranges.Compared with the conventional graph coloring register allocation,the improved algorithm fully consideres the interferences among the register allocation candidates for two register classes,thus achiving less memory access operations in register spilling and higher code performance.

Key words: Register allocation, Compiler, Graph coloring algorithm, Register spilling, Optimization