[Clang] Missing AddressSpaceCast on CXX PointerToMember global.

[jhuber6]

The following code crashed when run on an NVIDIA or AMD GPU due to a missing address space cast https://godbolt.org/z/3vx6avrT6.

struct S {
    int x;
};

[[clang::loader_uninitialized]] S [[clang::address_space(3)]] s;

int &lookup(int S::*in) {
    return s.*in;
}

The generated IR accesses the global s but does not emit an address space cast to the generic address space. We do not emit an address space cast, because it is missing from the AST like should normally be applied prior to the ReturnStmt.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Joseph Huber (jhuber6)

The following code crashed when run on an NVIDIA or AMD GPU due to a missing address space cast https://godbolt.org/z/3vx6avrT6. ```c++ struct S { int x; };

[[clang::loader_uninitialized]] S [[clang::address_space(3)]] s;

int &lookup(int S::*in) {
return s.*in;
}

The generated IR accesses the global `s` but does not emit an address space cast  to the generic address space. We do not emit an address space cast, because it is missing from the AST like should normally be applied prior to the `ReturnStmt`.
</details>

[shafik]

CC @erichkeane

[jhuber6]

I was trying to look through this myself, I'm thinking that this needs to happen when we record the underlying struct that we apply the member access to, since it doesn't seem like we store any of that information in the MemberPointer AST type. Some suggestions would be welcome.