[llvm] [InstCombine] Simplify nonnull pointers (PR #128111)

[Nikita Popov via llvm-commits]

nikic wrote:

https://llvm-compile-time-tracker.com/compare.php?from=70dfcf83a6bf580e0df50cc6c50d4ba1f9c5250a&to=57a65fa59634d5a0e207063675ed47ecfe47d44c&stat=instructions:u => Interesting results, looks like this has a *major* positive impact on clang.

https://github.com/llvm/llvm-project/pull/128111