[clang] [clang][SPIR-V] Treat AMDGCN builtin pointers in AS 0 as generic (PR #234504)

[Alex Voicu via cfe-commits]

https://github.com/AlexVlx approved this pull request.

LGTM, thanks! This is a fine workaround but the AS impedance mismatch remains a problem, which I'll try to address in general in an upcoming PR.

https://github.com/llvm/llvm-project/pull/234504