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

[Piotr Fusik via llvm-commits]

https://github.com/pfusik requested changes to this pull request.

> Actually, if the call isn't in the use-def chain (say `call void @foo()`), it will still remain in the transformed loop as ValueEvolution doesn't see it. However, if the call is side-effecting, the transform would be unsound, as the number of loop iterations have changed: this is probably a bug in HashRecognize, and I'll look into this.

We need that potential miscompile fixed.

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