Speculative hedge: Regulating compile-time speculation against profile variations

The speculation yield and dependence height heuristic is extended to explicitly minimize the penalty suffered by paths other than the execution paths. Since the execution time of a path is determined by the number of cycles spent between a path's entrance and exit in the scheduling scope, the heuristic attempts to eliminate unnecessary speculation that delays any path's exit. Such control of speculation makes the performance less sensitive to the actual path taken at run time. Thus, the proposed speculative hedge has a strong emphasis on achieving minimal delay to all exits that controls over-speculation in a superblock/hyperblock scheduler.