[llvm] [WebAssembly][GlobalISel] Implement pointer and memory ops. (PR #206885)

[Demetrius Kanios via llvm-commits]

QuantumSegfault wrote:

Ping @arsenm 

Still need answers on the two points.

I'd prefer to undo that latest commit, as I find it more cumbersome.

And postpone "fixing" G_PTRTOINT, G_INTTOPTR, and G_PTRMASK to the hypothetical future (other targets are doing the same workaround for now). Somebody else with better understanding of GISel internals might have better luck finding a neater solution (to map G_PTRMASK to `and`; vs adding a new DAG node).

https://github.com/llvm/llvm-project/pull/206885