isl_basic_map_lexopt: preinitialize domain

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

diff --git a/isl_map.c b/isl_map.c
index 58b20f2..6fffa60 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -6062,19 +6062,33 @@ __isl_give isl_set *isl_set_partial_lexmax(
                        dom, empty);
 }
 
+/* Compute the lexicographic minimum (or maximum if "max" is set)
+ * of "bmap" over its domain.
+ *
+ * Since we are not interested in the part of the domain space where
+ * there is no solution, we initialize the domain to those constraints
+ * of "bmap" that only involve the parameters and the input dimensions.
+ * This relieves the parametric programming engine from detecting those
+ * inequalities and transferring them to the context.  More importantly,
+ * it ensures that those inequalities are transferred first and not
+ * intermixed with inequalities that actually split the domain.
+ */
 __isl_give isl_map *isl_basic_map_lexopt(__isl_take isl_basic_map *bmap, int max)
 {
-       struct isl_basic_set *dom = NULL;
-       isl_space *dom_dim;
+       int n_div;
+       int n_out;
+       isl_basic_map *copy;
+       isl_basic_set *dom;
 
-       if (!bmap)
-               goto error;
-       dom_dim = isl_space_domain(isl_space_copy(bmap->dim));
-       dom = isl_basic_set_universe(dom_dim);
+       n_div = isl_basic_map_dim(bmap, isl_dim_div);
+       n_out = isl_basic_map_dim(bmap, isl_dim_out);
+       copy = isl_basic_map_copy(bmap);
+       copy = isl_basic_map_drop_constraints_involving_dims(copy,
+                                                       isl_dim_div, 0, n_div);
+       copy = isl_basic_map_drop_constraints_involving_dims(copy,
+                                                       isl_dim_out, 0, n_out);
+       dom = isl_basic_map_domain(copy);
        return isl_basic_map_partial_lexopt(bmap, dom, NULL, max);
-error:
-       isl_basic_map_free(bmap);
-       return NULL;
 }
 
 __isl_give isl_map *isl_basic_map_lexmin(__isl_take isl_basic_map *bmap)