isl_basic_set_opt: avoid invalid access on error path

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

diff --git a/isl_coalesce.c b/isl_coalesce.c
index 0152bef..c2c3bb4 100644 (file)
--- a/isl_coalesce.c
+++ b/isl_coalesce.c
@@ -3,7 +3,7 @@
  * Copyright 2010      INRIA Saclay
  * Copyright 2012      Ecole Normale Superieure
  *
- * Use of this software is governed by the GNU LGPLv2.1 license
+ * Use of this software is governed by the MIT license
  *
  * Written by Sven Verdoolaege, K.U.Leuven, Departement
  * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
@@ -1533,6 +1533,16 @@ error:
 /* For each pair of basic maps in the map, check if the union of the two
  * can be represented by a single basic map.
  * If so, replace the pair by the single basic map and start over.
+ *
+ * Since we are constructing the tableaus of the basic maps anyway,
+ * we exploit them to detect implicit equalities and redundant constraints.
+ * This also helps the coalescing as it can ignore the redundant constraints.
+ * In order to avoid confusion, we make all implicit equalities explicit
+ * in the basic maps.  We don't call isl_basic_map_gauss, though,
+ * as that may affect the number of constraints.
+ * This means that we have to call isl_basic_map_gauss at the end
+ * of the computation to ensure that the basic maps are not left
+ * in an unexpected state.
  */
 struct isl_map *isl_map_coalesce(struct isl_map *map)
 {
@@ -1562,6 +1572,10 @@ struct isl_map *isl_map_coalesce(struct isl_map *map)
                if (!ISL_F_ISSET(map->p[i], ISL_BASIC_MAP_NO_IMPLICIT))
                        if (isl_tab_detect_implicit_equalities(tabs[i]) < 0)
                                goto error;
+               map->p[i] = isl_tab_make_equalities_explicit(tabs[i],
+                                                               map->p[i]);
+               if (!map->p[i])
+                       goto error;
                if (!ISL_F_ISSET(map->p[i], ISL_BASIC_MAP_NO_REDUNDANT))
                        if (isl_tab_detect_redundant(tabs[i]) < 0)
                                goto error;
@@ -1576,6 +1590,7 @@ struct isl_map *isl_map_coalesce(struct isl_map *map)
                for (i = 0; i < map->n; ++i) {
                        map->p[i] = isl_basic_map_update_from_tab(map->p[i],
                                                                    tabs[i]);
+                       map->p[i] = isl_basic_map_gauss(map->p[i], NULL);
                        map->p[i] = isl_basic_map_finalize(map->p[i]);
                        if (!map->p[i])
                                goto error;