[llvm] Reland "[LICM] Sink unused l-invariant loads in preheader #157559" (PR #170204)

[Vigneshwar Jayakumar via llvm-commits]

VigneshwarJ wrote:

> Add test from the regression case?

I have added a test for scalar revolution update.  But for the stackoverflow [issue ](https://github.com/llvm/llvm-project/issues/168048) during compilation, it only happens for a big test case where I limit the stack size with ulimit -s command. Not sure how to add that as a regression test.

https://github.com/llvm/llvm-project/pull/170204