Data Parallel Performance Optimizations Using Array Aliasing

. The array aliasing mechanism provided in the Connection Machine Fortran (CMF) language and run--time system provides a unique way of identifying the memory address spaces local to processors within the global address space of distributed memory architectures, while staying in the data parallel programming paradigm. We show how the array aliasing feature can be used effectively in optimizing communication and computation performance. The constructs we present occur frequently in many scientific and engineering applications, and include various forms of aggregation and array reshaping through array aliasing. The effectiveness of the optimization techniques is demonstratedon an implementationof Anderson's hierarchicalO(N) N --body method. We also suggest a way of implementing the array aliasing feature in HPF by extending the semantics of the RESHAPE intrinsic function of Fortran 90 to include possible aliasing relationship between the parameter and returning arrays. Key words. Data pa..