Interactive loop interchanging: a facility for tuning sequential programs to parallel architectures

Loop interchanging is a powerful restructuring technique proposed for detecting implicit parallelism in conventional programming languages. There are several reasons for loop interchanging, and these are the same reasons that make the technique suitable for tuning programs to parallel architectures. This article discusses a new loop interchanging implementation in which the user can select a loop using distinct parts of the Do-loop definition in a Fortran-like language to be interchanged with either the inner-most or the outer-most Do-loop of a nested loop structure. The results of loop interchanging analysis are displayed on the screen after each iteration.