Serialize the 'IsConstexpr' bit of VarDecls. Fixes <rdar://problem/12328814>.

llvm-svn: 164335
diff --git a/clang/test/PCH/cxx11-constexpr.cpp b/clang/test/PCH/cxx11-constexpr.cpp
index ce43206..8b722ce 100644
--- a/clang/test/PCH/cxx11-constexpr.cpp
+++ b/clang/test/PCH/cxx11-constexpr.cpp
@@ -20,6 +20,13 @@
   int k;
 };
 
+constexpr int value = 7;
+
+template<typename T>
+constexpr T plus_seven(T other) {
+  return value + other;
+}
+
 #else
 
 static_assert(D(4).k == 9, "");
@@ -28,4 +35,6 @@
 constexpr B b; // expected-error {{constant expression}} expected-note {{non-constexpr}}
                // expected-note@9 {{here}}
 
+static_assert(plus_seven(3) == 10, "");
+
 #endif