[llvm] Reland "[LV]: Teach LV to recursively (de)interleave." (PR #125094)

[Florian Hahn via llvm-commits]

fhahn wrote:

@hassnaaHamdi I am not sure if new features can still be picked at this stage in the release (as they might introduce additional risk) or only bug-fixes. You could either check with @tstellar first or create a PR and take it from there. 

https://github.com/llvm/llvm-project/pull/125094