diff --git a/lib/AsmParser/llvmAsmParser.y b/lib/AsmParser/llvmAsmParser.y
index 13df7fe..0f2af20 100644
--- a/lib/AsmParser/llvmAsmParser.y
+++ b/lib/AsmParser/llvmAsmParser.y
@@ -2057,6 +2057,9 @@
       bool isVarArg = ParamTypes.size() && ParamTypes.back() == Type::VoidTy;
       if (isVarArg) ParamTypes.pop_back();
 
+      if (!(*$2)->isFirstClassType() && *$2 != Type::VoidTy)
+        ThrowException("LLVM functions cannot return aggregate types!");
+
       Ty = FunctionType::get($2->get(), ParamTypes, isVarArg);
       PFTy = PointerType::get(Ty);
     }