vtkPassInputTypeAlgorithm : Skip computation if inputs are not modified from last compute ?

I am exploring subclassing vtkPassInputTypeAlgorithm for some custom node-graph like processing since vtkExecutive view them as a pipeline

When implementing

vtkTypeBool vtkPassInputTypeAlgorithm::ProcessRequest	(	vtkInformation * 	request,
vtkInformationVector ** 	inputVector,
vtkInformationVector * 	outputVector 
)	

I have access to vtkInformationVector which I can retrieve a pointer to vtkInformation

I would like to be able to perform something akin to

bool isDirty(vtkInformationVector ** 	inputVector)

My hope is that with it, I maybe able to skip any heavy computation inside of ProcessRequest()
or is this already taken care of by vtkExecutive which knows not to call ProcessRequest() of an object if the inputVector has no changes

I am not familiar with the internals of VTK, hence the question.