Estimating register cost using spots

A modified register allocation algorithm whose register cost uses distinct spots is introduced. With this method, the five range of a variable can be viewed as a collection of spots, which are coordinate distances. Together with the usage counts of a variable and the increased weight on variables in loop structures, the cost of each variable already in a register is estimated. In the case where a spill is unavoidable, a variable in a register with minimum cost is chosen. Primary results show that this method increases speed about 21% in terms of the number of load/store instructions when compared with Chow's graph-coloring method.<>