[llvm] [InstCombine] Move nonnull assumptions to the base of a gep (PR #195650)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw commented:

I don't quite remember. Did we complete the mitigation for the `gep inbounds null, %iptr` idiom?


https://github.com/llvm/llvm-project/pull/195650