[llvm] [LoopUnroll] Skip remainder loop guard if skip unrolled loop (PR #156549)

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

> @valerydmit Would you please open an issue for the performance problem you described so we do not lose track of it? Thanks.

I opened [an issue](https://github.com/llvm/llvm-project/issues/173419).

https://github.com/llvm/llvm-project/pull/156549