--- a/js/src/gc/Verifier.cpp
+++ b/js/src/gc/Verifier.cpp
@@ -685,20 +685,22 @@ CheckGrayMarkingTracer::checkCell(Cell* 
     if (parent->isMarkedBlack() && cell->isMarkedGray()) {
         failures++;
 
         fprintf(stderr, "Found black to gray edge to ");
         dumpCellInfo(cell);
         fprintf(stderr, "\n");
         dumpCellPath();
 
+#ifdef DEBUG
         if (cell->getTraceKind() == JS::TraceKind::Object) {
             fprintf(stderr, "\n");
             DumpObject(static_cast<JSObject*>(cell), stderr);
         }
+#endif
     }
 }
 
 bool
 CheckGrayMarkingTracer::check(AutoLockForExclusiveAccess& lock)
 {
     if (!traceHeap(lock))
         return true; // Ignore failure.