A novel heuristic for selection of hyperblock in If-conversion

Abstract

In this paper we present a novel heuristic for selection of hyperblock in If-conversion. The if-conversion has been applied to be promising method for exploitation of ILP in the presence of control flow. The if-conversion in the prediction is responsible for control dependency between the branches and remaining instructions creating data dependency between the predicate definition and predicated structures of the program. As a result, the transformation of control flow becomes optimized traditional data flow and branch scheduling becomes reordering of serial instructions. The degree of ILP can be increased by overlapping multiple program path executions. The main idea behind this concept is to use a step beyond the prediction of common branch and permitting the architecture to have the information about the CFG (Control Flow Graph) components of the program to have better branch decision for ILP. The navigation bandwidth of prediction mechanism depends upon the degree of ILP. It can be increased by increasing control flow prediction in procedural languages at compile time. By this the size of initiation is increased that allows the overlapped execution of multiple independent flow of control. The multiple branch instruction can also be allowed as intermediate steps in order to increase the size of dynamic window to achieve a high degree of ILP exploitation.