Revisiting cycle shrinking

Abstract

Several loop transformation techniques have been designed to extract parallelism from nested loop structures. We first review two important approaches, known as Generalized Cycle Shrinking presented by Shang, O'Keefe and Fortes and the Index Shift Method introduced by Liu, Ho and Sheu. The main result of the paper is a new methodology that permits to combine cycle shrinking techniques with the index shift method. We present a new optimization method that produces the best scheduling vector, and we show that we can outperform previous results by an arbitrary speedup factor.