public void addEdge(final @Nullable Instruction beginInstruction, final @Nullable Instruction endInstruction) {
    if (beginInstruction == null || endInstruction == null) {
      return;
    }
    beginInstruction.addSucc(endInstruction);
    endInstruction.addPred(beginInstruction);
  }
public void addEdge(final @Nullable Instruction beginInstruction, final @Nullable Instruction endInstruction)