[clang] [CIR] Upstream emitAndUpdateRetAlloca (PR #129933)

[Erich Keane via cfe-commits]

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@@ -213,6 +222,11 @@ mlir::LogicalResult CIRGenFunction::emitFunctionBody(const clang::Stmt *body) {
 cir::FuncOp CIRGenFunction::generateCode(clang::GlobalDecl gd, cir::FuncOp fn,
                                          cir::FuncType funcType) {
   const auto funcDecl = cast<FunctionDecl>(gd.getDecl());
+  fnRetQualTy = funcDecl->getReturnType();
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erichkeane wrote:

This whole thing doesn't seem useful as far as I can tell, we should just be able to use the return type in `startFunction`

https://github.com/llvm/llvm-project/pull/129933