Handle emitting the assignment operator when the lhs is a reference. Fixes PR5227.

llvm-svn: 84518
diff --git a/clang/test/CodeGenCXX/references.cpp b/clang/test/CodeGenCXX/references.cpp
index 682aab3..8e0e1cb 100644
--- a/clang/test/CodeGenCXX/references.cpp
+++ b/clang/test/CodeGenCXX/references.cpp
@@ -130,3 +130,9 @@
   }
 }
 
+// PR5227.
+namespace PR5227 {
+void f(int &a) {
+  (a = 10) = 20;
+}
+}