In fact I don’t think we would need processors anymore if we were centrally storing all of the operations ever done in our processors.
Now fast retrieval is another problem for another thread.
I think you'd have to compare the data value before purging, and you can only do the deduplication (purge) if the block is actually the same, otherwise you have to keep the block (you can't replace it with the hash because the hash link in the pool points to different data)