diff --git a/lib/cretonne/src/lib.rs b/lib/cretonne/src/lib.rs
index aef83bd433..51a8d9b367 100644
--- a/lib/cretonne/src/lib.rs
+++ b/lib/cretonne/src/lib.rs
@@ -21,3 +21,4 @@ mod write;
 mod constant_hash;
 mod predicates;
 mod legalizer;
+mod ref_slice;
diff --git a/lib/cretonne/src/ref_slice.rs b/lib/cretonne/src/ref_slice.rs
new file mode 100644
index 0000000000..b9dbd55dd1
--- /dev/null
+++ b/lib/cretonne/src/ref_slice.rs
@@ -0,0 +1,18 @@
+//! Functions for converting a reference into a singleton slice.
+//!
+//! See also the ref_slice crate on crates.io.
+//!
+//! We define the functions here to avoid external dependencies, and to ensure that they are
+//! inlined in this crate.
+//!
+//! Despite their using an unsafe block, these functions are completely safe.
+
+use std::slice;
+
+pub fn ref_slice<T>(s: &T) -> &[T] {
+    unsafe { slice::from_raw_parts(s, 1) }
+}
+
+pub fn ref_slice_mut<T>(s: &mut T) -> &mut [T] {
+    unsafe { slice::from_raw_parts_mut(s, 1) }
+}