[llvm] [InstCombine] Prevent infinite loop with two shifts (PR #118806)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I think it may be better to address this by replacing the check in https://github.com/llvm/llvm-project/blob/5977d79c6ce41cfc4cbf18764eec8cae1c40f12a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp#L430 with a check for ImmConstant.

https://github.com/llvm/llvm-project/pull/118806