Why says that the graph based IR is `ANF IR`?

[GonChen]

Hi, @bartvm @breuleux
I have read the code of AnfNode. The Graph is composed by Apply, Parameter, and Constant.
I searched the definition of ANF.
But, I don't find the relation between the graph-based IR and the definition of ANF. From what view says the graph-based IR is an ANF IR?

I also seen your discussion about Graph-based ANF IR. But it still doesn't solve my question. Could you please give some explanation? Thanks very much.