isl_map_intersect: detect empty result also in case of adding a single constraint

Commit ed3b444 (isl_map_intersect: add special case for adding a single
constraint) added a special case of adding a single constraint but
neglected to detect an empty result in this special case.

diff --git a/isl_map.c b/isl_map.c
index 6840726..01f1758 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -1876,6 +1876,11 @@ static __isl_give isl_map *map_intersect_add_constraint(
        if (!map1->p[0])
                goto error;
 
+       if (isl_basic_map_fast_is_empty(map1->p[0])) {
+               isl_basic_map_free(map1->p[0]);
+               map1->n = 0;
+       }
+
        isl_map_free(map2);
 
        return map1;