isl_map_plain_is_disjoint: special case obviously empty inputs

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/isl_map_simplify.c b/isl_map_simplify.c
index 9001833..2582d08 100644 (file)
--- a/isl_map_simplify.c
+++ b/isl_map_simplify.c
@@ -2170,11 +2170,20 @@ int isl_map_plain_is_disjoint(__isl_keep isl_map *map1,
        __isl_keep isl_map *map2)
 {
        int i, j;
+       int disjoint;
        int intersect;
 
        if (!map1 || !map2)
                return -1;
 
+       disjoint = isl_map_plain_is_empty(map1);
+       if (disjoint < 0 || disjoint)
+               return disjoint;
+
+       disjoint = isl_map_plain_is_empty(map2);
+       if (disjoint < 0 || disjoint)
+               return disjoint;
+
        intersect = isl_map_plain_is_equal(map1, map2);
        if (intersect < 0 || intersect)
                return intersect < 0 ? -1 : 0;