[llvm] [SCEV] Add SCEVPtrToAddr, use when computing backedge taken counts. (PR #158032)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Happy to have this support, but I don't think we should use it for trip count calculation at this point, and only for explicit `ptrtoaddr` in IR. We have zero optimization support for this instruction currently, so I don't think we should be emitting it yet.

https://github.com/llvm/llvm-project/pull/158032