diff --git a/src/ir/subtype-exprs.h b/src/ir/subtype-exprs.h
index e2cf5b14f20..61a0d6a2267 100644
--- a/src/ir/subtype-exprs.h
+++ b/src/ir/subtype-exprs.h
@@ -368,8 +368,12 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
     }
     const auto& fields = curr->ref->type.getHeapType().getStruct().fields;
     auto type = fields[curr->index].type;
-    self()->noteSubtype(curr->expected,
-                        type.isRef() ? Type(HeapType::eq, Nullable) : type);
+    Type expectedType = type;
+    if (type.isRef()) {
+      expectedType =
+        Type(HeapTypes::eq.getBasic(type.getHeapType().getShared()), Nullable);
+    }
+    self()->noteSubtype(curr->expected, expectedType);
     self()->noteSubtype(curr->replacement, type);
   }
   void visitStructWait(StructWait* curr) {}
@@ -445,8 +449,12 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
       return;
     }
     auto type = curr->ref->type.getHeapType().getArray().element.type;
-    self()->noteSubtype(curr->expected,
-                        type.isRef() ? Type(HeapType::eq, Nullable) : type);
+    Type expectedType = type;
+    if (type.isRef()) {
+      expectedType =
+        Type(HeapTypes::eq.getBasic(type.getHeapType().getShared()), Nullable);
+    }
+    self()->noteSubtype(curr->expected, expectedType);
     self()->noteSubtype(curr->replacement, type);
   }
   void visitRefAs(RefAs* curr) {
diff --git a/test/lit/passes/unsubtyping-cmpxchg.wast b/test/lit/passes/unsubtyping-cmpxchg.wast
new file mode 100644
index 00000000000..91f28863e8d
--- /dev/null
+++ b/test/lit/passes/unsubtyping-cmpxchg.wast
@@ -0,0 +1,82 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited.
+;; RUN: wasm-opt %s -all --closed-world --unsubtyping -S -o - | filecheck %s
+
+(module
+  ;; CHECK:      (rec
+  ;; CHECK-NEXT:  (type $array-unshared (array (mut eqref)))
+
+  ;; CHECK:       (type $array-shared (shared (array (mut (ref null (shared eq))))))
+
+  ;; CHECK:       (type $struct-unshared (struct (field (mut eqref))))
+
+  ;; CHECK:       (type $struct-shared (struct (field (mut (ref null (shared eq))))))
+  (type $struct-shared (struct (field (mut (ref null (shared eq))))))
+  (type $struct-unshared (struct (field (mut eqref))))
+
+  (type $array-shared (shared (array (mut (ref null (shared eq))))))
+  (type $array-unshared (array (mut eqref)))
+
+  ;; CHECK:      (func $struct-shared-eq (type $7) (param $struct (ref $struct-shared)) (param $eq (ref null (shared eq))) (result (ref null (shared eq)))
+  ;; CHECK-NEXT:  (struct.atomic.rmw.cmpxchg $struct-shared 0
+  ;; CHECK-NEXT:   (local.get $struct)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $struct-shared-eq (param $struct (ref $struct-shared)) (param $eq (ref null (shared eq))) (result (ref null (shared eq)))
+    (struct.atomic.rmw.cmpxchg $struct-shared 0
+      (local.get $struct)
+      (local.get $eq)
+      (local.get $eq)
+    )
+  )
+
+  ;; CHECK:      (func $struct-unshared-eq (type $6) (param $struct (ref $struct-unshared)) (param $eq eqref) (result eqref)
+  ;; CHECK-NEXT:  (struct.atomic.rmw.cmpxchg $struct-unshared 0
+  ;; CHECK-NEXT:   (local.get $struct)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $struct-unshared-eq (param $struct (ref $struct-unshared)) (param $eq eqref) (result eqref)
+    (struct.atomic.rmw.cmpxchg $struct-unshared 0
+      (local.get $struct)
+      (local.get $eq)
+      (local.get $eq)
+    )
+  )
+
+  ;; CHECK:      (func $array-shared-eq (type $5) (param $array (ref $array-shared)) (param $eq (ref null (shared eq))) (result (ref null (shared eq)))
+  ;; CHECK-NEXT:  (array.atomic.rmw.cmpxchg $array-shared
+  ;; CHECK-NEXT:   (local.get $array)
+  ;; CHECK-NEXT:   (i32.const 0)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $array-shared-eq (param $array (ref $array-shared)) (param $eq (ref null (shared eq))) (result (ref null (shared eq)))
+    (array.atomic.rmw.cmpxchg $array-shared
+      (local.get $array)
+      (i32.const 0)
+      (local.get $eq)
+      (local.get $eq)
+    )
+  )
+
+  ;; CHECK:      (func $array-unshared-eq (type $4) (param $array (ref $array-unshared)) (param $eq eqref) (result eqref)
+  ;; CHECK-NEXT:  (array.atomic.rmw.cmpxchg $array-unshared
+  ;; CHECK-NEXT:   (local.get $array)
+  ;; CHECK-NEXT:   (i32.const 0)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:   (local.get $eq)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $array-unshared-eq (param $array (ref $array-unshared)) (param $eq eqref) (result eqref)
+    (array.atomic.rmw.cmpxchg $array-unshared
+      (local.get $array)
+      (i32.const 0)
+      (local.get $eq)
+      (local.get $eq)
+    )
+  )
+)