[clang] [clang][CodeGen] Promote point of GRO(CWG2563) (PR #151067)

[Chuanqi Xu via cfe-commits]

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@@ -768,6 +779,41 @@ struct GetReturnObjectManager {
     CGF.EmitAutoVarInit(GroEmission);
     Builder.CreateStore(Builder.getTrue(), GroActiveFlag);
   }
+
+  void EmitGroConv() {
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ChuanqiXu9 wrote:

We can add comment for:
1. the intention
2. the example IR before and after the function.

https://github.com/llvm/llvm-project/pull/151067