[clang] [clang][AMDGPU] Clean-up handling of named barrier type (PR #207687)

[Matt Arsenault via cfe-commits]

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@@ -68,6 +68,9 @@ enum class LangAS : unsigned {
   // Wasm specific address spaces.
   wasm_funcref,
 
+  // HIP-specific address spaces
+  hip_barrier,
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arsenm wrote:

Should avoid putting the language name here, special builtin types should work regardless of the language

https://github.com/llvm/llvm-project/pull/207687