[clang] [Clang] Track alloca element types to avoid getAllocatedType() calls (PR #181740)

[Oliver Hunt via cfe-commits]

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@@ -992,12 +993,13 @@ void CGHLSLRuntime::emitEntryFunction(const FunctionDecl *FD,
   CI->setCallingConv(Fn->getCallingConv());
 
   if (Fn->getReturnType() != CGM.VoidTy)
-    OutputSemantic.try_emplace(FD, CI);
+    OutputSemantic.try_emplace(FD, std::make_pair(CI, /*unused*/ nullptr));
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ojhunt wrote:

I think this unused should be just be `/*element type=*/` but I don't really know our style for tuples. @cor3ntin  or @AaronBallman ?

https://github.com/llvm/llvm-project/pull/181740