[clang] [clang][CodeGen] Return RValue from `EmitVAArg` (PR #94635)

[John McCall via cfe-commits]

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@@ -5988,12 +5988,29 @@ CGCallee CGCallee::prepareConcreteCallee(CodeGenFunction &CGF) const {
 
 /* VarArg handling */
 
-Address CodeGenFunction::EmitVAArg(VAArgExpr *VE, Address &VAListAddr) {
-  VAListAddr = VE->isMicrosoftABI()
-                 ? EmitMSVAListRef(VE->getSubExpr())
-                 : EmitVAListRef(VE->getSubExpr());
+RValue CodeGenFunction::EmitVAArg(VAArgExpr *VE, Address &VAListAddr) {
+  VAListAddr = VE->isMicrosoftABI() ? EmitMSVAListRef(VE->getSubExpr())
+                                    : EmitVAListRef(VE->getSubExpr());
   QualType Ty = VE->getType();
+  Address ResAddr = Address::invalid();
   if (VE->isMicrosoftABI())
-    return CGM.getTypes().getABIInfo().EmitMSVAArg(*this, VAListAddr, Ty);
-  return CGM.getTypes().getABIInfo().EmitVAArg(*this, VAListAddr, Ty);
+    ResAddr = CGM.getTypes().getABIInfo().EmitMSVAArg(*this, VAListAddr, Ty);
+  else
+    ResAddr = CGM.getTypes().getABIInfo().EmitVAArg(*this, VAListAddr, Ty);
+
+  switch (getEvaluationKind(VE->getType())) {
+  case TEK_Scalar: {
+    llvm::Value *Load = Builder.CreateLoad(ResAddr);
+    return RValue::get(Load);
+  }
+  case TEK_Complex: {
+    llvm::Value *Load = Builder.CreateLoad(ResAddr);
+    llvm::Value *Real = Builder.CreateExtractValue(Load, 0);
+    llvm::Value *Imag = Builder.CreateExtractValue(Load, 1);
+    return RValue::getComplex(std::make_pair(Real, Imag));
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rjmccall wrote:

There's an `EmitLoadOfComplex` you can use here.  You'll just need to `MakeAddrLValue` first.

https://github.com/llvm/llvm-project/pull/94635