Optimal Compilation of HPF Remappings

Fabien Coelho and Corinne Ancourt.
Report EMP CRI A-274, July 1995.
20 pages, 35 references.

This report is obsoleted by A-277 (abstract).


Applications with varying array access patterns in a parallel distributed memory machine require to dynamically change array mappings. HPF (High Performance Fortran) provides such remappings, possibly on partially replicated data, explicitly through the realign and redistribute directives and implicitly at procedure calls and returns. However such features are left out of the HPF subset or of the currently discussed HPF kernel for efficiency reason. This paper presents a new compilation technique to handle HPF remappings for message-passing parallel architectures. The first phase is global and removes all useless remappings that naturally appear in procedures. The second phase generates the actual remapping code and takes advantage of replications to shorten the remapping time. A minimal number of messages, containing only the required data, is sent over the network.

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