diff --git a/src/xdiff/xprepare.c b/src/xdiff/xprepare.c
index 3183d50eb..13b55aba7 100644
--- a/src/xdiff/xprepare.c
+++ b/src/xdiff/xprepare.c
@@ -305,7 +305,7 @@ int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 		return -1;
 	}
 
-	if (XDF_DIFF_ALG((xpp->flags) & XDF_HISTOGRAM_DIFF))
+	if (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)
 		xdl_free_classifier(&cf);
 
 	return 0;