[clang] [llvm] [HLSL][SPIR-V] implement SV_GroupID semantic lowering (PR #121521)

[Justin Bogner via llvm-commits]

https://github.com/bogner commented:

This basically LGTM but th SV_GroupID.ll test could use a fair amount of cleanup

https://github.com/llvm/llvm-project/pull/121521