[clang] [HLSL] Implement RWBuffer::operator[] via __builtin_hlsl_resource_getpointer (PR #117017)

[Helena Kotas via cfe-commits]

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@@ -4738,6 +4738,12 @@ def GetDeviceSideMangledName : LangBuiltin<"CUDA_LANG"> {
 }
 
 // HLSL
+def HLSLTypedBufferPointer : LangBuiltin<"HLSL_LANG"> {
+  let Spellings = ["__builtin_hlsl_resource_getpointer"];
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hekota wrote:

Is this for all buffer types or just typed buffers? The name has 'TypedBuffer' and does not match the spelling.

https://github.com/llvm/llvm-project/pull/117017