[llvm] [WIP] Extend data layout to add non zero null value for address space. (PR #83109)

[Jessica Clarke via llvm-commits]

https://github.com/jrtc27 requested changes to this pull request.

What is this thing? What are its semantics? What is it used for? This needs a LangRef change so people know what they’re looking at.

https://github.com/llvm/llvm-project/pull/83109