[llvm] [polly] [ConstraintElimination] Use SCEV ranges information for Loop counter (PR #91457)

[via llvm-commits]

v01dXYZ wrote:

I think I found a possible solution with a minor change in `IndVarSimplify` / `SimplifyIndVar`. It seems the instructions eligible to simplifications are only the ones within the current loop (cf `pushIVUsers`), I wonder if we can also consider eligible instructions that are not in any loop. It seems to work but I didn't test the performance regressions. So still WIP.

https://github.com/llvm/llvm-project/pull/91457