Implement C++0x nullptr.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71405 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index aa4920f..34b0187 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -299,7 +299,9 @@
       { return APValue((Expr*)0, 0); }
   APValue VisitConditionalOperator(ConditionalOperator *E);
   APValue VisitChooseExpr(ChooseExpr *E)
-    { return Visit(E->getChosenSubExpr(Info.Ctx)); }
+      { return Visit(E->getChosenSubExpr(Info.Ctx)); }
+  APValue VisitCXXNullPtrLiteralExpr(CXXNullPtrLiteralExpr *E)
+      { return APValue((Expr*)0, 0); }
   // FIXME: Missing: @protocol, @selector
 };
 } // end anonymous namespace