diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
index d0ea75c7623f4..7228bcda54356 100644
--- a/src/libcore/cmp.rs
+++ b/src/libcore/cmp.rs
@@ -1208,6 +1208,21 @@ mod impls {
         #[inline]
         fn gt(&self, other: &&mut B) -> bool { PartialOrd::gt(*self, *other) }
     }
+    #[stable(feature = "partial_ord_mut_ref", since = "1.40.0")]
+    impl<A: ?Sized, B: ?Sized> PartialOrd<&B> for &mut A where A: PartialOrd<B> {
+        #[inline]
+        fn partial_cmp(&self, other: &&B) -> Option<Ordering> {
+            PartialOrd::partial_cmp(*self, *other)
+        }
+        #[inline]
+        fn lt(&self, other: &&B) -> bool { PartialOrd::lt(*self, *other) }
+        #[inline]
+        fn le(&self, other: &&B) -> bool { PartialOrd::le(*self, *other) }
+        #[inline]
+        fn ge(&self, other: &&B) -> bool { PartialOrd::ge(*self, *other) }
+        #[inline]
+        fn gt(&self, other: &&B) -> bool { PartialOrd::gt(*self, *other) }
+    }
     #[stable(feature = "rust1", since = "1.0.0")]
     impl<A: ?Sized> Ord for &mut A where A: Ord {
         #[inline]
diff --git a/src/tools/miri b/src/tools/miri
index 2adc39f27b7fd..394a9d5d29507 160000
--- a/src/tools/miri
+++ b/src/tools/miri
@@ -1 +1 @@
-Subproject commit 2adc39f27b7fd2d06b3d1d470827928766731a1d
+Subproject commit 394a9d5d295078f7b846d6833c73b2661704e97e