[clang] [llvm] [SPIRV] GPU intrinsics (PR #131190)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 commented:

So this is basically a serialization of the headers in `gpuintrin.h` as IR? I'll need to defer to the people more familiar with the backend / IR layer but I have a few comments.

https://github.com/llvm/llvm-project/pull/131190