[clang] [SPIR-V] Initial support for SPIR-V in `gpuintrin.h` (PR #174910)

[via cfe-commits]

fineg74 wrote:

Couple of questions:
1. The implementation does not contain some API that for example nvptxintrin.h and amdgpuintrin.h containe like __gpu_is_ptr_private/__gpu_is_ptr_local/__gpu_sync_threads which are used across the code.
2. Is there a reason to introduce and use new builtin intrinsics vs existing spirv builtin API (https://github.com/llvm/llvm-project/blob/main/clang/lib/Headers/__clang_spirv_builtins.h) like I did here: https://github.com/llvm/llvm-project/pull/174675 ?


https://github.com/llvm/llvm-project/pull/174910