isl_pw_qpolynomial_intersect_domain: drop pieces that end up having empty domain

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

diff --git a/isl_pw_templ.c b/isl_pw_templ.c
index 7aa329b..4a61e1a 100644 (file)
--- a/isl_pw_templ.c
+++ b/isl_pw_templ.c
@@ -311,10 +311,17 @@ __isl_give PW *FN(PW,intersect_domain)(__isl_take PW *pw, __isl_take isl_set *se
        if (!pw)
                goto error;
 
-       for (i = 0; i < pw->n; ++i) {
+       for (i = pw->n - 1; i >= 0; --i) {
                pw->p[i].set = isl_set_intersect(pw->p[i].set, isl_set_copy(set));
                if (!pw->p[i].set)
                        goto error;
+               if (isl_set_fast_is_empty(pw->p[i].set)) {
+                       isl_set_free(pw->p[i].set);
+                       FN(EL,free)(pw->p[i].FIELD);
+                       if (i != pw->n - 1)
+                               pw->p[i] = pw->p[pw->n - 1];
+                       pw->n--;
+               }
        }
        
        isl_set_free(set);