diff --git a/library/compiler-builtins/src/lib.rs b/library/compiler-builtins/src/lib.rs
index 04bf2d05c95d..21d7902b2c22 100644
--- a/library/compiler-builtins/src/lib.rs
+++ b/library/compiler-builtins/src/lib.rs
@@ -13,6 +13,7 @@
 #![feature(core_intrinsics)]
 #![feature(naked_functions)]
 #![feature(staged_api)]
+#![feature(i128_type)]
 #![no_builtins]
 #![unstable(feature = "compiler_builtins_lib",
             reason = "Compiler builtins. Will never become stable.",