[llvm] Add a pass to collect dropped var stats for MIR (PR #120501)

[Nikita Popov via llvm-commits]

nikic wrote:

Could you please take a look at my comment at https://github.com/llvm/llvm-project/pull/115566#discussion_r1847990774? I've already repeated this at https://github.com/llvm/llvm-project/pull/117044#issuecomment-2515692928. This is my third attempt to reach out about this issue.

https://github.com/llvm/llvm-project/pull/120501