index 6b8d130..42526f0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
-@@ -1,5 +1,5 @@
+@@ -1,6 +1,6 @@
+-#![feature(asm)]
-#![feature(llvm_asm)]
--#![feature(const_fn)]
+-#![feature(const_fn)] // see https://github.com/rust-lang/rfcs/pull/2632
++#![cfg_attr(nightly, feature(asm))]
+#![cfg_attr(nightly, feature(llvm_asm))]
+#![cfg_attr(nightly, feature(const_fn))]
#![cfg_attr(not(test), no_std)]