1. A computerized method for compiler optimization using a graph updated by analyzing dominance relationships between a plurality of functions of the software program, the method comprising: receiving, at a computer including at least one processor and memory, a source code of a software program, the source code having a plurality of functions; identifying a plurality of intraprocedural dominator graphs each for another of the plurality of functions of the source code; combining, by the at least one processor, the plurality of intraprocedural dominator graphs to create a combined interprocedural dominance graph with edges that logically connect between nodes of the plurality of functions of the source code; identifying, by the at least one processor, a plurality of interprocedural dominance relations between nodes in different functions of the plurality of functions of the source code using the combined interprocedural dominance graph; computing a static single assignment (SSA) form based on the plurality of interprocedural dominance relations; performing an analysis of the received software program according to the plurality of interprocedural dominance relations; updating the combined interprocedural dominance graph by: making localized changes to one or more of the plurality of functions of the source code; identifying a group of functions from the plurality of functions, wherein members of the group are affected by the localized changes; re-computing an interprocedural dominator set for the group; and re-connecting only nodes of the group; and using the updated combined interprocedural dominance graph for compiler optimization.