[llvm] [SCEV] Introduce loop-uniform SCEV classification. (PR #194304)

[Mikael Holmen via llvm-commits]

mikaelholmen wrote:

Thanks for the revert @mstorsjo . We hit the problem downstream as well.
Reduced opt reproducer: https://godbolt.org/z/W8b6EaYcx 

https://github.com/llvm/llvm-project/pull/194304