[llvm] Reduce shl64 to shl32 if shift range is [63-32] (PR #125574)

[Nikita Popov via llvm-commits]

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

Please read https://llvm.org/docs/InstCombineContributorGuide.html and in particular https://llvm.org/docs/InstCombineContributorGuide.html#canonicalization-and-target-independence.

This transform should be in the backend.

https://github.com/llvm/llvm-project/pull/125574