Fix a crash in MallocOverflowSecurityChecker. Patch by Lei Zhang.

llvm-svn: 140648
diff --git a/clang/test/Analysis/malloc-overflow.cpp b/clang/test/Analysis/malloc-overflow.cpp
new file mode 100644
index 0000000..c1ac6be
--- /dev/null
+++ b/clang/test/Analysis/malloc-overflow.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=experimental.security.MallocOverflow -verify %s
+
+class A {
+public:
+  A& operator<<(const A &a);
+};
+
+void f() {
+  A a = A(), b = A();
+  a << b;
+}