vec.h (vnull::operator vec): Add constexpr keyword for C++11 and later.

	* vec.h (vnull::operator vec): Add constexpr keyword for
	C++11 and later.

From-SVN: r240443

1 files changed, 3 insertions, 0 deletions

diff --git a/gcc/vec.h b/gcc/vec.h
index eb8c270..959871b 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -414,6 +414,9 @@ struct GTY((user)) vec
 struct vnull
 {
   template <typename T, typename A, typename L>
+#if __cpp_constexpr >= 200704
+  constexpr
+#endif
   operator vec<T, A, L> () { return vec<T, A, L>(); }
 };
 extern vnull vNULL;