In this paper, we describe two new ideas by shich HPF compiler can deal with irregular computations effectivelly. The fist mechanism invokes a user specified mapping procedure via a set of compiler directives. The directives allow the user to use program arrays to describe graph connectivity, spatial location of array elements and computationsl load. The second is a simple consrvative method hatt insible to reuse previously computed results form inspectors (e.g communications schedules, loop iteration partitons, information that associates off-processor data copies with on processor buffer locations. We present performance rslults for these mechanism from a fortran 90D compiler implementation