Automatic Array Alignment in Data-Parallel Programs

摘要

The authors present a framework for the automatic determination of array alignments in data-parallel languages such as Fortran 90. Their language model handles array sectioning, reductions, spreads, transpositions, and masked operations. They decompose alignment functions into three constituents: axis, stride, and offset. For each of these subproblems, they show how to solve the alignment problem for a basic block of code, possibly containing common subexpressions. Alignments are generated for all array objects in the code, both named program variables and intermediate results. The alignments obtained by the algorithms are more general than those provided by the owner-computes rule. Finally, they present some ideas for dealing with control flow, replication, and dynamic alignments that depend on loop induction variables. (Copyright (c) 1992 Xerox Corporation. All rights reserved.)