[llvm] [llvm][ConstraintElimination]Insert ConditionFact into loop header in case of monotonic induction variables (PR #112080)

[Matthias Braun via llvm-commits]

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

- While this already appears to seems to improve existing tests (which is a good sign), a change like this should probably add new tests specifically geared towards this change as well.
- I think the requires some sort check to rule out overflows to be correct? (add a test showing that no transformation happens in cases with potential overflow).

https://github.com/llvm/llvm-project/pull/112080