[llvm] [LoopIdiom] Use HashRecognize to optimize CRC (PR #143208)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

Results from LLVM compile time tracker [look okay](https://llvm-compile-time-tracker.com/compare.php?from=b9d3a644c2716e651b388f9fff660b12fdba577c&to=966d3a12ebe5e41fe5410718f1f8e318ce22d885&stat=instructions:u), although there is a crash in ThinLTO.

The results from llvm-opt-benchmark indicate that there are quite a few opportunities successfully exploited by HashRecognize, although the results look a bit strange.

https://github.com/llvm/llvm-project/pull/143208