diff --git a/src/undo.c b/src/undo.c
index ba7c0b8..5b95379 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -1385,7 +1385,7 @@
 {
     int		i;
     u_entry_T	*uep;
-    char_u	**array;
+    char_u	**array = NULL;
     char_u	*line;
     int		line_len;
 
@@ -1402,7 +1402,8 @@
     uep->ue_size = undo_read_4c(bi);
     if (uep->ue_size > 0)
     {
-	array = (char_u **)U_ALLOC_LINE(sizeof(char_u *) * uep->ue_size);
+	if (uep->ue_size < LONG_MAX / (int)sizeof(char_u *))
+	    array = (char_u **)U_ALLOC_LINE(sizeof(char_u *) * uep->ue_size);
 	if (array == NULL)
 	{
 	    *error = TRUE;
@@ -1410,8 +1411,6 @@
 	}
 	vim_memset(array, 0, sizeof(char_u *) * uep->ue_size);
     }
-    else
-	array = NULL;
     uep->ue_array = array;
 
     for (i = 0; i < uep->ue_size; ++i)