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

[Demetrius Kanios via llvm-commits]

================
@@ -165,6 +199,94 @@ bool WebAssemblyInstructionSelector::select(MachineInstr &I) {
     I.setDesc(TII.get(TargetOpcode::IMPLICIT_DEF));
     return RBI.constrainGenericRegister(DefReg, *DefRC, MRI) != nullptr;
   }
+  case G_PTRTOINT: {
----------------
QuantumSegfault wrote:

Not according to AArch:

```
  case TargetOpcode::G_INTTOPTR:
    // The importer is currently unable to import pointer types since they
    // didn't exist in SelectionDAG.
    return selectCopy(I, TII, MRI, TRI, RBI);
```

G_PTRMASK and G_PTRTOINT is also handled during ISel.

But this wouldn't be the first time I've been tasked with deeper fixes... I'll look into it.

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