diff --git a/src/librustc_data_structures/obligation_forest/mod.rs b/src/librustc_data_structures/obligation_forest/mod.rs
index c079146edbf42..fb2d3291a601b 100644
--- a/src/librustc_data_structures/obligation_forest/mod.rs
+++ b/src/librustc_data_structures/obligation_forest/mod.rs
@@ -342,6 +342,16 @@ impl<O: ForestObligation> ObligationForest<O> {
             }
         }
 
+        if stalled {
+            // There's no need to perform marking, cycle processing and compression when nothing
+            // changed.
+            return Outcome {
+                completed: vec![],
+                errors: errors,
+                stalled: stalled,
+            };
+        }
+
         self.mark_as_waiting();
         self.process_cycles(processor);