A precise dataflow analysis should effectively exploit the semantic information presented by conditional branch statements.Most traditional systems,however,either ignore the logical conditions,or try hard to handle logical conditions with logical reasoning which is rather difficult and infeasible for paralleling systems.With the aim to solve this problem efficiently and effectively,the authors introduce the computation function model and then successfully convert the logical reasoning problems into problems of deciding the coverage relationship of Omega regions which are substantially more feasible to be solved by contemporary paralleling compilers.