Software pipelining with path selection

Software pipelining is an efficient scheduling technique for VLIW and superscalar processors. Performance improvement by using conventional algorithms has been restricted due to resource occupation by infrequently executed control paths and long data-dependent paths because all the control paths in a loop are pipelined. In this paper, we propose an algorithm that performs pipelining by selecting frequently executed paths in a loop. This algorithm provides for the possibility to optimally pipeline, not only frequently executed paths, but also non-innermost loops. This has been difficult in the past. We performed a comparative evaluation of this algorithm against conventional algorithms using benchmark programs for non-numerical application, and verified its high efficiency.