[llvm-branch-commits] [flang] [mlir] [mlir][LLVM] Replace `llvm::LLVMPointerType` by `ptr::PtrType` (PR #173094)

[Fabian Mora via llvm-branch-commits]

fabianmcg wrote:

> Printing `!llvm.ptr` for a type that does not actually exist does not seem right to me, why are you trying to do this?

This was the original plan, the reasoning being:
- Smaller churn footprint in tests, as no changes are needed there.
  - An important point here is, a simple regex script wouldn't be able to update the tests automatically. So manual labor or a dedicated tool would be needed. 
- It's convenient when writing tests and IR, as `!llvm.ptr<3>` is much smaller and readable than `!ptr.ptr<#llvm.address_space<3>>`.
- We already have some form of type/attr aliasing in the IR, so this is just using an extension of aliasing to keep things simple.

https://github.com/llvm/llvm-project/pull/173094