diff --git a/src/list.c b/src/list.c
index 8e67a61..16e5983 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1945,7 +1945,13 @@
     if (res == FAIL)
 	res = ITEM_COMPARE_FAIL;
     else
+    {
 	res = (int)tv_get_number_chk(&rettv, &sortinfo->item_compare_func_err);
+	if (res > 0)
+	    res = 1;
+	else if (res < 0)
+	    res = -1;
+    }
     if (sortinfo->item_compare_func_err)
 	res = ITEM_COMPARE_FAIL;  // return value has wrong type
     clear_tv(&rettv);
diff --git a/src/testdir/test_sort.vim b/src/testdir/test_sort.vim
index 47c5859..82f70ff 100644
--- a/src/testdir/test_sort.vim
+++ b/src/testdir/test_sort.vim
@@ -58,6 +58,7 @@
 func Test_sort_numbers()
   call assert_equal([3, 13, 28], sort([13, 28, 3], 'N'))
   call assert_equal(['3', '13', '28'], sort(['13', '28', '3'], 'N'))
+  call assert_equal([3997, 4996], sort([4996, 3997], 'Compare1'))
 endfunc
 
 func Test_sort_float()
diff --git a/src/version.c b/src/version.c
index 38f9017..99a94e2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3449,
+/**/
     3448,
 /**/
     3447,