diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 3b6bae0d15..81de412875 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -197,8 +197,9 @@ void xdl_free_env(xdfenv_t *xe) {
 }
 
 
-static bool xdl_clean_mmatch(uint8_t const *action, ptrdiff_t i, ptrdiff_t s, ptrdiff_t e) {
+static bool xdl_clean_mmatch(uint8_t const *action, ptrdiff_t i, ptrdiff_t len) {
 	ptrdiff_t r, rdis0, rpdis0, rdis1, rpdis1;
+	ptrdiff_t s = 0, e = len - 1;
 
 	/*
 	 * Limits the window that is examined during the similar-lines
@@ -342,7 +343,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 		uint8_t action = action1[i];
 
 		if (action == INVESTIGATE) {
-			if (!xdl_clean_mmatch(action1, i, 0, len1 - 1))
+			if (!xdl_clean_mmatch(action1, i, len1))
 				action = KEEP;
 			else
 				action = DISCARD;
@@ -363,7 +364,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 		uint8_t action = action2[i];
 
 		if (action == INVESTIGATE) {
-			if (!xdl_clean_mmatch(action2, i, 0, len2 - 1))
+			if (!xdl_clean_mmatch(action2, i, len2))
 				action = KEEP;
 			else
 				action = DISCARD;