Question about MemNode

[Ramón García]

I am trying to understand the code in memnode.hpp

What is the meaning of the nodes Control, Memory and Address that a MemNode has?

I understand more or less that a MemNode defines a memory reference,
Memory defines the base and Address defines the offset. But the
meaning of Control is still unclear to me (a comment describes it as
"// When is it safe to do this load?").