--- a/js/src/gc/GCRuntime.h
+++ b/js/src/gc/GCRuntime.h
@@ -830,17 +830,17 @@ class GCRuntime
      * stuff. At various times we check this counter and, if it has changed, we
      * run an immediate, non-incremental GC to clean up the dead
      * zones. This should happen very rarely.
      */
     unsigned objectsMarkedInDeadZones;
 
     bool poked;
 
-    mozilla::Atomic<js::HeapState> heapState;
+    volatile js::HeapState heapState;
 
     /*
      * These options control the zealousness of the GC. The fundamental values
      * are nextScheduled and gcDebugCompartmentGC. At every allocation,
      * nextScheduled is decremented. When it reaches zero, we do either a full
      * or a compartmental GC, based on debugCompartmentGC.
      *
      * At this point, if zeal_ is one of the types that trigger periodic