[IR] Values that are initialized but not graph inputs do not have their ValueInfo preserved

[justinchuby]

Currently the values in the graph that are not inputs and do not have producing nodes are not registered with the graph. Their value info is not preserved at serialization. We need a way to easily access them and be able to serialize them.

[gramalingam]

Just to clarify, I guess these are initializers (that are not inputs). I realize the title says this, but I wasn't looking at that first!

How do users create them? (In previous frameworks/approaches, typically we used to create "Constant()" op nodes, depending on subsequent processing, if desired, to convert them into initializers.)

[justinchuby]

Just to clarify, I guess these are initializers (that are not inputs). I realize the title says this, but I wasn't looking at that first!

Thanks for clarifying - the title was referring to "initialized objects", but yes they are typically initializers.

How do users create them? (In previous frameworks/approaches, typically we used to create "Constant()" op nodes, depending on subsequent processing, if desired, to convert them into initializers.)

These values are simply ir.Value as inputs to nodes. When deserializing they are created on the fly, but they are not referenced by the graph, and the serializers only create ValueInfo for node outputs and not inputs.

I think we can simply create ValueInfo for all initializers. I will double check if we are doing this already.