[llvm] [SCEV] Fix NSW flag propagation in getGEPExpr (PR #155269)

[Nikita Popov via llvm-commits]

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

Cross-posting previous review: https://github.com/llvm/llvm-project/pull/155145#discussion_r2296554287

https://github.com/llvm/llvm-project/pull/155269