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Overlapping communication with computation is a well-known approach to improving performance. Previous research has focused on optimizations performed by the programmer. This paper presents a compiler algorithm that automatically determines the appropriate loop indices of a given nested loop and applies loop interchange and tiling in order to overlap communication with computation. The algorithm avoids generating redundant communication by providing a framework for combining information on data dependence, communication, and reuse. It also describes a method of generating messages to exchange data between processors for tiled loops on distributed memory machines. The algorithm has been implemented in our High Performance Fortran (HPF) compiler, and experimental results have shown its effectiveness on distributed memory machines, such as the RISC System/6000 Scalable POWERparallel System. This paper also discusses the architectural problems of efficient optimization. [ABSTRACT FROM AUTHOR]

This paper considers the role of run-time diagnostic checking in enforcing the rules of the Pascal programming language. Run- time diagnostic checks must be both complete (covering all language requirements) and efficient. Further, such checks should be implemented so that the cost of enforcing the correct use of a given construct is borne by users of that construct. This paper describes simple and efficient mechanisms currently in use with a diagnostic Pascal compiler that monitor the run-time behavior of such sensitive Pascal constructs as pointers, variant records, reference (i.e., vat) parameters, and with statements. The use of these mechanisms with related constructs in other languages is considered. Language modifications that simplify run-time checking are also noted. [ABSTRACT FROM AUTHOR]

In 1965, four undergraduates at the University of Waterloo wrote Watfor, a fast student-oriented Fortran compiler for the school's IBM 7040, largely because the available Fortran compiler was slow and offered weak diagnostic and debugging tools. This article describes the birth and evolution of the Watfor family and explores how it fits into the University of Waterloo's unique-within-Canada cooperative education program and pedagogical philosophy. [ABSTRACT FROM PUBLISHER]

The article describes the Aggregate Remote Memory Copy Interface (ARMCI), a portable high performance remote memory access communication interface needed both for developing applications and for creating a communication layer for libraries and compiler run-time systems. One of the design goals for ARMCI is to optimize performance of noncontiguous data transfers. Areas of its application include: data transfer operations; atomic operations; locks; and memory management and synchronization operations.