[clang] [llvm] [HLSL][DXIL][SPRIV] Added `GroupMemoryBarrier()` (PR #185383)

[Steven Perron via cfe-commits]

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s-perron wrote:

```suggestion
}

attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
```

https://github.com/llvm/llvm-project/pull/185383