Efficient compile-time analysis of cache behaviour for programs with IF statements

Abstract

This paper presents an analytical method for analysing efficiently the cache behaviour of Perfect loop nests containing IF statements with compile-time-analysable conditionals. We discuss the derivations of reuse vectors in the presence of IF statements, present miss equations for characterising the cache behaviour of a program and give algorithms for solving these equations for cache misses. We show that our method, together with loop sinking, can be used to analyse a large number of imperfect loop nests that cannot be analysed previously-17% more loop nests than previously in SPECfp95, Perfect Suite, Livermore kernels, Linpack and Lapack. Validation against cache simulation demonstrates the efficiency and accuracy of our method. Our method can be used to guide compiler cache optimisations and improve the performance of cache simulators and profilers.