Allow instantiation of NULL expressions and statements

llvm-svn: 71889
diff --git a/clang/lib/Sema/SemaTemplateInstantiateExpr.cpp b/clang/lib/Sema/SemaTemplateInstantiateExpr.cpp
index c2007c6..08c388e 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateExpr.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateExpr.cpp
@@ -432,6 +432,9 @@
 
 Sema::OwningExprResult 
 Sema::InstantiateExpr(Expr *E, const TemplateArgumentList &TemplateArgs) {
+  if (!E)
+    return Owned((Expr *)0);
+
   TemplateExprInstantiator Instantiator(*this, TemplateArgs);
   return Instantiator.Visit(E);
 }