isl_map_simplify.c: uset_gist: break early if intersection is empty

diff --git a/isl_map_simplify.c b/isl_map_simplify.c
index bb48508..faa0b93 100644 (file)
--- a/isl_map_simplify.c
+++ b/isl_map_simplify.c
@@ -1409,6 +1409,8 @@ static struct isl_basic_set *uset_gist(struct isl_basic_set *bset,
                                        isl_basic_set_copy(context));
        if (!bset)
                goto error;
+       if (isl_basic_set_fast_is_empty(bset))
+               goto done;
 
        if (bset->n_eq > 0) {
                struct isl_basic_set *affine_hull;