[llvm] [LLVM] InstCount pass implemented when enabling stats (PR #171658)

[Arthur Eubanks via llvm-commits]

https://github.com/aeubanks approved this pull request.

lgtm, I think this is great for getting IR stats!

nitpick on the PR title, we're not "implementing" InstCount, we're adding it to the pipeline

https://github.com/llvm/llvm-project/pull/171658