diff --git a/rts/sm/CNF.c b/rts/sm/CNF.c
index 8d0ebccaf3fd5d0a2cff77759e107afcc11e438b..d0447f867c02a265e950aaa70c57fe7a4e715748 100644
--- a/rts/sm/CNF.c
+++ b/rts/sm/CNF.c
@@ -281,6 +281,7 @@ compactFree(StgCompactNFData *str)
     }
 }
 
+#if defined(DEBUG)
 void
 compactMarkKnown(StgCompactNFData *str)
 {
@@ -319,7 +320,6 @@ countCompactBlocks(bdescr *outer)
     return count;
 }
 
-#if defined(DEBUG)
 // Like countCompactBlocks, but adjusts the size so each mblock is assumed to
 // only contain BLOCKS_PER_MBLOCK blocks.  Used in memInventory().
 StgWord