diff --git a/test/FrontendC++/thunk-weak-odr.cpp b/test/FrontendC++/thunk-weak-odr.cpp
new file mode 100644
index 00000000000..9f6a11d8f5a
--- /dev/null
+++ b/test/FrontendC++/thunk-weak-odr.cpp
@@ -0,0 +1,33 @@
+// RUN: %llvmgxx %s -S -o - | FileCheck %s
+// <rdar://problem/7929157>
+
+struct A {
+  virtual int f() { return 1; }
+};
+
+struct B {
+  virtual int f() { return 2; }
+};
+
+struct C : A, B {
+  virtual int f() { return 3; }
+};
+
+struct D : C {
+  virtual int f() { return 4; }
+};
+
+static int f(D* d) {
+  B* b = d;
+  return b->f();
+};
+
+int g() {
+  D d;
+  return f(&d);
+}
+
+// Thunks should be marked as "weak ODR", not just "weak".
+//
+// CHECK: define weak_odr i32 @_ZThn8_N1C1fEv
+// CHECK: define weak_odr i32 @_ZThn8_N1D1fEv