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

[Joel E. Denny via llvm-commits]

jdenny-ornl wrote:

> @jdenny-ornl , this patch caused more than 25% performance degradation due to additional spills/reloads. Could you please take a look? [f.zip](https://github.com/user-attachments/files/23277796/f.zip) To reproduce compile the attached file with O3 using flang or clang.

Thanks for the report.  Are you using `-pass-remarks-missed=regalloc` or some other tool to see the performance change?

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