diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 12bb659dda3..681a6622b3c 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1136,6 +1136,9 @@ bool LLParser::ParseArgumentList(std::vector<ArgInfo> &ArgList,
 bool LLParser::ParseFunctionType(PATypeHolder &Result) {
   assert(Lex.getKind() == lltok::lparen);
 
+  if (!FunctionType::isValidReturnType(Result))
+    return TokError("invalid function return type");
+  
   std::vector<ArgInfo> ArgList;
   bool isVarArg;
   unsigned Attrs;