isl_map_transitive_closure: break early if input map doesn't compose with itself

[platform/upstream/isl.git] / isl_transitive_closure.c

diff --git a/isl_transitive_closure.c b/isl_transitive_closure.c
index 369d0fb..ba7153b 100644 (file)
--- a/isl_transitive_closure.c
+++ b/isl_transitive_closure.c
@@ -610,6 +610,7 @@ static __isl_give isl_map *construct_component(__isl_take isl_dim *dim,
 {
        struct isl_set *domain = NULL;
        struct isl_set *range = NULL;
+       struct isl_set *overlap;
        struct isl_map *app = NULL;
        struct isl_map *path = NULL;
 
@@ -617,6 +618,20 @@ static __isl_give isl_map *construct_component(__isl_take isl_dim *dim,
        domain = isl_set_coalesce(domain);
        range = isl_map_range(isl_map_copy(map));
        range = isl_set_coalesce(range);
+       overlap = isl_set_intersect(isl_set_copy(domain), isl_set_copy(range));
+       if (isl_set_is_empty(overlap) == 1) {
+               isl_set_free(domain);
+               isl_set_free(range);
+               isl_set_free(overlap);
+               isl_dim_free(dim);
+
+               map = isl_map_copy(map);
+               map = isl_map_add(map, isl_dim_in, 1);
+               map = isl_map_add(map, isl_dim_out, 1);
+               map = set_path_length(map, 1, 1);
+               return map;
+       }
+       isl_set_free(overlap);
        app = isl_map_from_domain_and_range(domain, range);
        app = isl_map_add(app, isl_dim_in, 1);
        app = isl_map_add(app, isl_dim_out, 1);