Revisiting Loop Transformations with X10 Clocks

International audienceLoop transformations are known to be important for performance of compute-intensive programs, and are often used to expose parallelism. However, many transformations involving loops often obfuscate the code, and are cumbersome to apply by hand. The goal of this paper is to explore alternative methods for expressing parallelism that are more friendly to the programmer. In particular, we seek to expose parallelism without significantly changing the original loop structure. We illustrate how clocks in X10 can be used to express some of the traditional loop transformations, in the presence of parallelism, in a manner that we believe to be less invasive. Specifically, expressing parallelism corresponding to one-dimensional affine schedules can be achieved without modifying the original loop structure and/or statements