8 Transformations

KAP Fortran for OpenVMS ALPHA transformations convert standard Fortran constructs into forms that have better serial performance and which make more efficient use of the memory hierarchy of Digital's Alpha computers.

In addition, KAP identifies opportunities for concurrent execution of loops, identifying them with directives for the Digital Fortran compiler, and transforms vectorizable loops to enhance the vectorization capability of the Digital Fortran compiler.

This chapter describes some of the possible transformations in this process:

• Memory management for data locality

• Loop reordering

• Serial optimizations

• Dusty-Deck IF transformations

• Loop unrolling

• Loop rerolling

Unless otherwise noted, the examples in this chapter were run with the command qualifiers /optimize=5 , /roundoff=2 , and /scalaropt=2 .