PR1963: Address of function is a constant expression

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49212 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 11fcc41..5205702 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -453,6 +453,8 @@
     const Decl *D = cast<DeclRefExpr>(this)->getDecl();
     if (const VarDecl *VD = dyn_cast<VarDecl>(D))
       return VD->hasGlobalStorage();
+    if (isa<FunctionDecl>(D))
+      return true;
     return false;
   }
   case MemberExprClass: {