[llvm] [SCEV] Refactor forgetLoop and forgetValue to improve compile time (PR #198759)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Can you please split the forgetLoop() and the forgetValue() changes into separate PRs?

These are very high risk changes. We've had to revert or adjust attempted improvements to the invalidation many times in the past, because some new weird edge case shows up.

https://github.com/llvm/llvm-project/pull/198759