METHOD AND APPARATUS FOR IMPROVING PERFORMANCE OF A PROGRAM USING A LOOP INTERCHANGE,LOOP DISTRIBUTION,LOOP INTERCHANGE SEQUENCE

A compiler optimizing procedure improves a sequence of memory addressing actions of a program, wherein the program includes a plurality of do loops. The procedure includes the steps of: performing an interchange of do loops, within a set of nested loops, to move at least one loop of the set to a position of an outer loop, wherein the one loop manifests a condition which prevents application of a distribution action thereto; attempting a distribution of next outermost loops so as to isolate a code segment in the program from remaining interior loops in the set of nested loops; and if the distribution is performed, determining for each remaining interior loop if an interchange with another interior loop will improve an efficiency of execution of the program and if yes, performing the loop interchange.