When your comments and your code are out-of-sync, the test case is wrong.

llvm-svn: 123379
diff --git a/clang/lib/CodeGen/Mangle.cpp b/clang/lib/CodeGen/Mangle.cpp
index 0dfa052..b8ae1e7 100644
--- a/clang/lib/CodeGen/Mangle.cpp
+++ b/clang/lib/CodeGen/Mangle.cpp
@@ -1477,7 +1477,7 @@
 
 void CXXNameMangler::mangleType(const PackExpansionType *T) {
   // <type>  ::= Dp <type>          # pack expansion (C++0x)
-  Out << "sp";
+  Out << "Dp";
   mangleType(T->getPattern());
 }