Mark as referenced the functions from instantiated UserDefinedLiterals.

Fixes rdar://13589856

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index f68de26..8356095 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -6173,6 +6173,8 @@
 template<typename Derived>
 ExprResult
 TreeTransform<Derived>::TransformUserDefinedLiteral(UserDefinedLiteral *E) {
+  if (FunctionDecl *FD = E->getDirectCallee())
+    SemaRef.MarkFunctionReferenced(E->getLocStart(), FD);
   return SemaRef.MaybeBindToTemporary(E);
 }