An approach to efficient interprocedural analysis for program parallelization and restructuring is presented. Such analysis is needed for parallelizing loops which contain procedure calls. Our approach captures call effect on data dependencies by propagating the precise information of array subscripts from the called procedure. This allows the optimizing compiler to choose an efficient yet precise data dependence test scheme depending on the complexity of array reference patterns. The other existing methods do not provide such flexibility, hence may suffer from either imprecision or inefficiency. The paper also discusses usage of classical summary information in several important transformations for program parallelization. Experimental results are reported.