Linear-time algorithm to determine the maximum number of iterations of the iterative algorithm for data-flow analysis for reducible loops

摘要

A compiler converts a high level language program into a corresponding machine level language program. The compiler forms an initial control flow graph of the high level language program with nodes and edge, the nodes including a starting node, initializing a collapse count to zero, and sets the initial control flow graph as a current control flow graph. The compiler performs iterative collapsing operations on the current control flow graph until only a single node remains. After performing the iterative collapsing operations, data flow analysis is performed on the initial control flow graph for a number of iterations equal to one greater than the collapse count. Then, the machine level language program corresponding to the high level language program is generated based upon the data flow analysis.