[llvm] [DirectX] Support the CBufferLoadLegacy operation (PR #128699)

[Justin Bogner via llvm-commits]

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@@ -816,6 +822,19 @@ def CreateHandle : DXILOp<57, createHandle> {
   let attributes = [Attributes<DXIL1_0, [ReadOnly]>];
 }
 
+def CBufferLoadLegacy : DXILOp<59, cbufferLoadLegacy> {
+  let Doc = "reads from a TypedBuffer";
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bogner wrote:

Nice catch. I updated this to use the doc wording from [DXIL.rst](https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/DXIL.rst#operations-via-external-functions)

https://github.com/llvm/llvm-project/pull/128699