[llvm] [InferAddressSpaces] Initialize op(generic const, generic const, ...) -> generic (PR #172143)

[Hongyu Chen via llvm-commits]

XChy wrote:

> an example would be `%nullphi = phi <2 x ptr> [ zeroinitializer, %entry ], [ <ptr addrspacecast(ptr addrspace(3) @glob to ptr), ptr addrspacecast(ptr addrspace(3) @glob1 to ptr)>, %if1]` We can infer AS 3 from the second constant.

Yes. It's possible to infer the AS from these constant expressions, but the current implementation doesn't consider it.

https://github.com/llvm/llvm-project/pull/172143