[llvm] [LoopFlatten] Use loop versioning when overflow can't be disproven (PR #78576)

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

Looks like a very good addition. 
Just a quick question. The pass is off by default, but have you benchmarked this? Just wanted to check if there are no unexpected results (e.g. the extra runtime checks regressing things).

https://github.com/llvm/llvm-project/pull/78576