diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 02e0cf731364..7a4768ff73f0 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -7086,6 +7086,7 @@ nsBlockFrame::CheckFloats(nsBlockReflowState& aState)
 
   if (!equal || lineFloats.Count() != storedFloats.Count()) {
     NS_WARNING("nsBlockFrame::CheckFloats: Explicit float list is out of sync with float cache");
+#if defined(DEBUG_roc)
     nsIFrameDebug::RootFrameList(GetPresContext(), stdout, 0);
     for (i = 0; i < lineFloats.Count(); ++i) {
       printf("Line float: %p\n", lineFloats.ElementAt(i));
@@ -7093,6 +7094,7 @@ nsBlockFrame::CheckFloats(nsBlockReflowState& aState)
     for (i = 0; i < storedFloats.Count(); ++i) {
       printf("Stored float: %p\n", storedFloats.ElementAt(i));
     }
+#endif
   }
 #endif