[llvm] [InferAddressSpaces] Infer pointer stored and then loaded from global variable (PR #159755)

[Wenju He via llvm-commits]

wenju-he wrote:

> This probably belongs in an IPO pass, and not this function pass

does it make sense to add a module pass variant of InferAddressSpacesPass? Module pass would allow more optimizations, like modifying global variable type and function argument type after inferring.

https://github.com/llvm/llvm-project/pull/159755