+ int k;
+
+ if (!bset)
+ goto error;
+ bset = isl_basic_set_extend_constraints(bset, 0, 1);
+ k = isl_basic_set_alloc_inequality(bset);
+ if (k < 0)
+ goto error;
+ isl_seq_clr(bset->ineq[k] + 1, isl_basic_set_total_dim(bset));
+ isl_int_set_si(bset->ineq[k][0], 1);
+ bset = isl_basic_set_preimage(bset, T);
+ return bset;
+error:
+ isl_mat_free(T);
+ isl_basic_set_free(bset);
+ return NULL;
+}
+
+/* Compute the convex hull of a pair of basic sets without any parameters or
+ * integer divisions, where the convex hull is known to be pointed,
+ * but the basic sets may be unbounded.
+ *
+ * We turn this problem into the computation of a convex hull of a pair
+ * _bounded_ polyhedra by "changing the direction of the homogeneous
+ * dimension". This idea is due to Matthias Koeppe.
+ *
+ * Consider the cones in homogeneous space that correspond to the
+ * input polyhedra. The rays of these cones are also rays of the
+ * polyhedra if the coordinate that corresponds to the homogeneous
+ * dimension is zero. That is, if the inner product of the rays
+ * with the homogeneous direction is zero.
+ * The cones in the homogeneous space can also be considered to
+ * correspond to other pairs of polyhedra by chosing a different
+ * homogeneous direction. To ensure that both of these polyhedra
+ * are bounded, we need to make sure that all rays of the cones
+ * correspond to vertices and not to rays.
+ * Let s be a direction such that <s, r> > 0 for all rays r of both cones.
+ * Then using s as a homogeneous direction, we obtain a pair of polytopes.
+ * The vector s is computed in valid_direction.
+ *
+ * Note that we need to consider _all_ rays of the cones and not just
+ * the rays that correspond to rays in the polyhedra. If we were to
+ * only consider those rays and turn them into vertices, then we
+ * may inadvertently turn some vertices into rays.
+ *
+ * The standard homogeneous direction is the unit vector in the 0th coordinate.
+ * We therefore transform the two polyhedra such that the selected
+ * direction is mapped onto this standard direction and then proceed
+ * with the normal computation.
+ * Let S be a non-singular square matrix with s as its first row,
+ * then we want to map the polyhedra to the space
+ *
+ * [ y' ] [ y ] [ y ] [ y' ]
+ * [ x' ] = S [ x ] i.e., [ x ] = S^{-1} [ x' ]
+ *
+ * We take S to be the unimodular completion of s to limit the growth
+ * of the coefficients in the following computations.
+ *
+ * Let b_i + A_i x >= 0 be the constraints of polyhedron i.
+ * We first move to the homogeneous dimension
+ *
+ * b_i y + A_i x >= 0 [ b_i A_i ] [ y ] [ 0 ]
+ * y >= 0 or [ 1 0 ] [ x ] >= [ 0 ]
+ *
+ * Then we change directoin
+ *
+ * [ b_i A_i ] [ y' ] [ y' ]
+ * [ 1 0 ] S^{-1} [ x' ] >= 0 or [ b_i' A_i' ] [ x' ] >= 0
+ *
+ * Then we compute the convex hull of the polytopes b_i' + A_i' x' >= 0
+ * resulting in b' + A' x' >= 0, which we then convert back
+ *
+ * [ y ] [ y ]
+ * [ b' A' ] S [ x ] >= 0 or [ b A ] [ x ] >= 0
+ *
+ * The polyhedron b + A x >= 0 is then the convex hull of the input polyhedra.
+ */
+static struct isl_basic_set *convex_hull_pair_pointed(
+ struct isl_basic_set *bset1, struct isl_basic_set *bset2)
+{
+ struct isl_ctx *ctx = NULL;
+ struct isl_vec *dir = NULL;
+ struct isl_mat *T = NULL;
+ struct isl_mat *T2 = NULL;
+ struct isl_basic_set *hull;
+ struct isl_set *set;
+
+ if (!bset1 || !bset2)
+ goto error;
+ ctx = bset1->ctx;
+ dir = valid_direction(isl_basic_set_copy(bset1),
+ isl_basic_set_copy(bset2));
+ if (!dir)
+ goto error;
+ T = isl_mat_alloc(bset1->ctx, dir->size, dir->size);
+ if (!T)
+ goto error;
+ isl_seq_cpy(T->row[0], dir->block.data, dir->size);
+ T = isl_mat_unimodular_complete(T, 1);
+ T2 = isl_mat_right_inverse(isl_mat_copy(T));
+
+ bset1 = homogeneous_map(bset1, isl_mat_copy(T2));
+ bset2 = homogeneous_map(bset2, T2);
+ set = isl_set_alloc_dim(isl_basic_set_get_dim(bset1), 2, 0);
+ set = isl_set_add(set, bset1);
+ set = isl_set_add(set, bset2);
+ hull = uset_convex_hull(set);
+ hull = isl_basic_set_preimage(hull, T);
+
+ isl_vec_free(dir);
+
+ return hull;
+error:
+ isl_vec_free(dir);
+ isl_basic_set_free(bset1);
+ isl_basic_set_free(bset2);
+ return NULL;
+}
+
+/* Compute the convex hull of a pair of basic sets without any parameters or
+ * integer divisions.
+ *
+ * If the convex hull of the two basic sets would have a non-trivial
+ * lineality space, we first project out this lineality space.
+ */
+static struct isl_basic_set *convex_hull_pair(struct isl_basic_set *bset1,
+ struct isl_basic_set *bset2)
+{
+ struct isl_basic_set *lin;
+
+ if (isl_basic_set_is_bounded(bset1) || isl_basic_set_is_bounded(bset2))
+ return convex_hull_pair_pointed(bset1, bset2);
+
+ lin = induced_lineality_space(isl_basic_set_copy(bset1),
+ isl_basic_set_copy(bset2));
+ if (!lin)
+ goto error;
+ if (isl_basic_set_is_universe(lin)) {
+ isl_basic_set_free(bset1);
+ isl_basic_set_free(bset2);
+ return lin;
+ }
+ if (lin->n_eq < isl_basic_set_total_dim(lin)) {
+ struct isl_set *set;
+ set = isl_set_alloc_dim(isl_basic_set_get_dim(bset1), 2, 0);
+ set = isl_set_add(set, bset1);
+ set = isl_set_add(set, bset2);
+ return modulo_lineality(set, lin);
+ }
+ isl_basic_set_free(lin);
+
+ return convex_hull_pair_pointed(bset1, bset2);
+error:
+ isl_basic_set_free(bset1);
+ isl_basic_set_free(bset2);
+ return NULL;
+}
+
+/* Compute the lineality space of a basic set.
+ * We currently do not allow the basic set to have any divs.
+ * We basically just drop the constants and turn every inequality
+ * into an equality.
+ */
+struct isl_basic_set *isl_basic_set_lineality_space(struct isl_basic_set *bset)
+{
+ int i, k;
+ struct isl_basic_set *lin = NULL;
+ unsigned dim;
+
+ if (!bset)
+ goto error;
+ isl_assert(bset->ctx, bset->n_div == 0, goto error);
+ dim = isl_basic_set_total_dim(bset);
+
+ lin = isl_basic_set_alloc_dim(isl_basic_set_get_dim(bset), 0, dim, 0);
+ if (!lin)
+ goto error;
+ for (i = 0; i < bset->n_eq; ++i) {
+ k = isl_basic_set_alloc_equality(lin);
+ if (k < 0)
+ goto error;
+ isl_int_set_si(lin->eq[k][0], 0);
+ isl_seq_cpy(lin->eq[k] + 1, bset->eq[i] + 1, dim);
+ }
+ lin = isl_basic_set_gauss(lin, NULL);
+ if (!lin)
+ goto error;
+ for (i = 0; i < bset->n_ineq && lin->n_eq < dim; ++i) {
+ k = isl_basic_set_alloc_equality(lin);
+ if (k < 0)
+ goto error;
+ isl_int_set_si(lin->eq[k][0], 0);
+ isl_seq_cpy(lin->eq[k] + 1, bset->ineq[i] + 1, dim);
+ lin = isl_basic_set_gauss(lin, NULL);
+ if (!lin)
+ goto error;
+ }
+ isl_basic_set_free(bset);
+ return lin;
+error:
+ isl_basic_set_free(lin);
+ isl_basic_set_free(bset);
+ return NULL;
+}
+
+/* Compute the (linear) hull of the lineality spaces of the basic sets in the
+ * "underlying" set "set".
+ */
+static struct isl_basic_set *uset_combined_lineality_space(struct isl_set *set)
+{
+ int i;
+ struct isl_set *lin = NULL;
+
+ if (!set)
+ return NULL;
+ if (set->n == 0) {
+ struct isl_dim *dim = isl_set_get_dim(set);
+ isl_set_free(set);
+ return isl_basic_set_empty(dim);
+ }
+
+ lin = isl_set_alloc_dim(isl_set_get_dim(set), set->n, 0);
+ for (i = 0; i < set->n; ++i)
+ lin = isl_set_add(lin,
+ isl_basic_set_lineality_space(isl_basic_set_copy(set->p[i])));
+ isl_set_free(set);
+ return isl_set_affine_hull(lin);
+}
+
+/* Compute the convex hull of a set without any parameters or
+ * integer divisions.
+ * In each step, we combined two basic sets until only one
+ * basic set is left.
+ * The input basic sets are assumed not to have a non-trivial
+ * lineality space. If any of the intermediate results has
+ * a non-trivial lineality space, it is projected out.
+ */
+static struct isl_basic_set *uset_convex_hull_unbounded(struct isl_set *set)
+{
+ struct isl_basic_set *convex_hull = NULL;
+
+ convex_hull = isl_set_copy_basic_set(set);
+ set = isl_set_drop_basic_set(set, convex_hull);
+ if (!set)
+ goto error;
+ while (set->n > 0) {
+ struct isl_basic_set *t;
+ t = isl_set_copy_basic_set(set);
+ if (!t)
+ goto error;
+ set = isl_set_drop_basic_set(set, t);
+ if (!set)
+ goto error;
+ convex_hull = convex_hull_pair(convex_hull, t);
+ if (set->n == 0)
+ break;
+ t = isl_basic_set_lineality_space(isl_basic_set_copy(convex_hull));
+ if (!t)
+ goto error;
+ if (isl_basic_set_is_universe(t)) {
+ isl_basic_set_free(convex_hull);
+ convex_hull = t;
+ break;
+ }
+ if (t->n_eq < isl_basic_set_total_dim(t)) {
+ set = isl_set_add(set, convex_hull);
+ return modulo_lineality(set, t);
+ }
+ isl_basic_set_free(t);
+ }
+ isl_set_free(set);
+ return convex_hull;
+error:
+ isl_set_free(set);
+ isl_basic_set_free(convex_hull);
+ return NULL;
+}
+
+/* Compute an initial hull for wrapping containing a single initial
+ * facet by first computing bounds on the set and then using these
+ * bounds to construct an initial facet.
+ * This function is a remnant of an older implementation where the
+ * bounds were also used to check whether the set was bounded.
+ * Since this function will now only be called when we know the
+ * set to be bounded, the initial facet should probably be constructed
+ * by simply using the coordinate directions instead.
+ */
+static struct isl_basic_set *initial_hull(struct isl_basic_set *hull,
+ struct isl_set *set)
+{
+ struct isl_mat *bounds = NULL;
+ unsigned dim;
+ int k;
+
+ if (!hull)
+ goto error;
+ bounds = independent_bounds(set);
+ if (!bounds)
+ goto error;
+ isl_assert(set->ctx, bounds->n_row == isl_set_n_dim(set), goto error);
+ bounds = initial_facet_constraint(set, bounds);
+ if (!bounds)
+ goto error;
+ k = isl_basic_set_alloc_inequality(hull);
+ if (k < 0)
+ goto error;
+ dim = isl_set_n_dim(set);
+ isl_assert(set->ctx, 1 + dim == bounds->n_col, goto error);
+ isl_seq_cpy(hull->ineq[k], bounds->row[0], bounds->n_col);
+ isl_mat_free(bounds);
+
+ return hull;
+error:
+ isl_basic_set_free(hull);
+ isl_mat_free(bounds);
+ return NULL;
+}
+
+struct max_constraint {
+ struct isl_mat *c;
+ int count;
+ int ineq;
+};
+
+static int max_constraint_equal(const void *entry, const void *val)
+{
+ struct max_constraint *a = (struct max_constraint *)entry;
+ isl_int *b = (isl_int *)val;
+
+ return isl_seq_eq(a->c->row[0] + 1, b, a->c->n_col - 1);
+}
+
+static void update_constraint(struct isl_ctx *ctx, struct isl_hash_table *table,
+ isl_int *con, unsigned len, int n, int ineq)
+{
+ struct isl_hash_table_entry *entry;
+ struct max_constraint *c;
+ uint32_t c_hash;
+
+ c_hash = isl_seq_hash(con + 1, len, isl_hash_init());
+ entry = isl_hash_table_find(ctx, table, c_hash, max_constraint_equal,
+ con + 1, 0);
+ if (!entry)
+ return;
+ c = entry->data;
+ if (c->count < n) {
+ isl_hash_table_remove(ctx, table, entry);
+ return;
+ }
+ c->count++;
+ if (isl_int_gt(c->c->row[0][0], con[0]))
+ return;
+ if (isl_int_eq(c->c->row[0][0], con[0])) {
+ if (ineq)
+ c->ineq = ineq;
+ return;
+ }
+ c->c = isl_mat_cow(c->c);
+ isl_int_set(c->c->row[0][0], con[0]);
+ c->ineq = ineq;
+}
+
+/* Check whether the constraint hash table "table" constains the constraint
+ * "con".
+ */
+static int has_constraint(struct isl_ctx *ctx, struct isl_hash_table *table,
+ isl_int *con, unsigned len, int n)
+{
+ struct isl_hash_table_entry *entry;
+ struct max_constraint *c;
+ uint32_t c_hash;
+
+ c_hash = isl_seq_hash(con + 1, len, isl_hash_init());
+ entry = isl_hash_table_find(ctx, table, c_hash, max_constraint_equal,
+ con + 1, 0);
+ if (!entry)
+ return 0;
+ c = entry->data;
+ if (c->count < n)
+ return 0;
+ return isl_int_eq(c->c->row[0][0], con[0]);
+}
+
+/* Check for inequality constraints of a basic set without equalities
+ * such that the same or more stringent copies of the constraint appear
+ * in all of the basic sets. Such constraints are necessarily facet
+ * constraints of the convex hull.
+ *
+ * If the resulting basic set is by chance identical to one of
+ * the basic sets in "set", then we know that this basic set contains
+ * all other basic sets and is therefore the convex hull of set.
+ * In this case we set *is_hull to 1.
+ */
+static struct isl_basic_set *common_constraints(struct isl_basic_set *hull,
+ struct isl_set *set, int *is_hull)
+{
+ int i, j, s, n;
+ int min_constraints;
+ int best;
+ struct max_constraint *constraints = NULL;
+ struct isl_hash_table *table = NULL;
+ unsigned total;
+
+ *is_hull = 0;
+
+ for (i = 0; i < set->n; ++i)
+ if (set->p[i]->n_eq == 0)
+ break;
+ if (i >= set->n)
+ return hull;
+ min_constraints = set->p[i]->n_ineq;
+ best = i;
+ for (i = best + 1; i < set->n; ++i) {
+ if (set->p[i]->n_eq != 0)
+ continue;
+ if (set->p[i]->n_ineq >= min_constraints)
+ continue;
+ min_constraints = set->p[i]->n_ineq;
+ best = i;
+ }
+ constraints = isl_calloc_array(hull->ctx, struct max_constraint,
+ min_constraints);
+ if (!constraints)
+ return hull;
+ table = isl_alloc_type(hull->ctx, struct isl_hash_table);
+ if (isl_hash_table_init(hull->ctx, table, min_constraints))
+ goto error;
+
+ total = isl_dim_total(set->dim);
+ for (i = 0; i < set->p[best]->n_ineq; ++i) {
+ constraints[i].c = isl_mat_sub_alloc(hull->ctx,
+ set->p[best]->ineq + i, 0, 1, 0, 1 + total);
+ if (!constraints[i].c)
+ goto error;
+ constraints[i].ineq = 1;
+ }
+ for (i = 0; i < min_constraints; ++i) {
+ struct isl_hash_table_entry *entry;
+ uint32_t c_hash;
+ c_hash = isl_seq_hash(constraints[i].c->row[0] + 1, total,
+ isl_hash_init());
+ entry = isl_hash_table_find(hull->ctx, table, c_hash,
+ max_constraint_equal, constraints[i].c->row[0] + 1, 1);
+ if (!entry)
+ goto error;
+ isl_assert(hull->ctx, !entry->data, goto error);
+ entry->data = &constraints[i];
+ }
+
+ n = 0;
+ for (s = 0; s < set->n; ++s) {
+ if (s == best)
+ continue;
+
+ for (i = 0; i < set->p[s]->n_eq; ++i) {
+ isl_int *eq = set->p[s]->eq[i];
+ for (j = 0; j < 2; ++j) {
+ isl_seq_neg(eq, eq, 1 + total);
+ update_constraint(hull->ctx, table,
+ eq, total, n, 0);
+ }
+ }
+ for (i = 0; i < set->p[s]->n_ineq; ++i) {
+ isl_int *ineq = set->p[s]->ineq[i];
+ update_constraint(hull->ctx, table, ineq, total, n,
+ set->p[s]->n_eq == 0);
+ }
+ ++n;
+ }
+
+ for (i = 0; i < min_constraints; ++i) {
+ if (constraints[i].count < n)
+ continue;
+ if (!constraints[i].ineq)
+ continue;
+ j = isl_basic_set_alloc_inequality(hull);
+ if (j < 0)
+ goto error;
+ isl_seq_cpy(hull->ineq[j], constraints[i].c->row[0], 1 + total);
+ }
+
+ for (s = 0; s < set->n; ++s) {
+ if (set->p[s]->n_eq)
+ continue;
+ if (set->p[s]->n_ineq != hull->n_ineq)
+ continue;
+ for (i = 0; i < set->p[s]->n_ineq; ++i) {
+ isl_int *ineq = set->p[s]->ineq[i];
+ if (!has_constraint(hull->ctx, table, ineq, total, n))
+ break;
+ }
+ if (i == set->p[s]->n_ineq)
+ *is_hull = 1;
+ }
+
+ isl_hash_table_clear(table);
+ for (i = 0; i < min_constraints; ++i)
+ isl_mat_free(constraints[i].c);
+ free(constraints);
+ free(table);
+ return hull;
+error:
+ isl_hash_table_clear(table);
+ free(table);
+ if (constraints)
+ for (i = 0; i < min_constraints; ++i)
+ isl_mat_free(constraints[i].c);
+ free(constraints);
+ return hull;
+}
+
+/* Create a template for the convex hull of "set" and fill it up
+ * obvious facet constraints, if any. If the result happens to
+ * be the convex hull of "set" then *is_hull is set to 1.
+ */
+static struct isl_basic_set *proto_hull(struct isl_set *set, int *is_hull)
+{
+ struct isl_basic_set *hull;
+ unsigned n_ineq;
+ int i;
+
+ n_ineq = 1;
+ for (i = 0; i < set->n; ++i) {
+ n_ineq += set->p[i]->n_eq;
+ n_ineq += set->p[i]->n_ineq;
+ }
+ hull = isl_basic_set_alloc_dim(isl_dim_copy(set->dim), 0, 0, n_ineq);
+ hull = isl_basic_set_set_rational(hull);
+ if (!hull)
+ return NULL;
+ return common_constraints(hull, set, is_hull);
+}
+
+static struct isl_basic_set *uset_convex_hull_wrap(struct isl_set *set)
+{
+ struct isl_basic_set *hull;
+ int is_hull;
+
+ hull = proto_hull(set, &is_hull);
+ if (hull && !is_hull) {
+ if (hull->n_ineq == 0)
+ hull = initial_hull(hull, set);
+ hull = extend(hull, set);
+ }
+ isl_set_free(set);
+
+ return hull;
+}
+
+/* Compute the convex hull of a set without any parameters or
+ * integer divisions. Depending on whether the set is bounded,
+ * we pass control to the wrapping based convex hull or
+ * the Fourier-Motzkin elimination based convex hull.
+ * We also handle a few special cases before checking the boundedness.
+ */
+static struct isl_basic_set *uset_convex_hull(struct isl_set *set)
+{
+ int i;
+ struct isl_basic_set *convex_hull = NULL;
+ struct isl_basic_set *lin;
+
+ if (isl_set_n_dim(set) == 0)
+ return convex_hull_0d(set);
+
+ set = isl_set_coalesce(set);
+ set = isl_set_set_rational(set);
+
+ if (!set)
+ goto error;
+ if (!set)
+ return NULL;
+ if (set->n == 1) {
+ convex_hull = isl_basic_set_copy(set->p[0]);
+ isl_set_free(set);
+ return convex_hull;
+ }
+ if (isl_set_n_dim(set) == 1)
+ return convex_hull_1d(set);
+
+ if (isl_set_is_bounded(set))
+ return uset_convex_hull_wrap(set);
+
+ lin = uset_combined_lineality_space(isl_set_copy(set));
+ if (!lin)
+ goto error;
+ if (isl_basic_set_is_universe(lin)) {
+ isl_set_free(set);
+ return lin;
+ }
+ if (lin->n_eq < isl_basic_set_total_dim(lin))
+ return modulo_lineality(set, lin);
+ isl_basic_set_free(lin);
+
+ return uset_convex_hull_unbounded(set);
+error:
+ isl_set_free(set);
+ isl_basic_set_free(convex_hull);
+ return NULL;
+}
+
+/* This is the core procedure, where "set" is a "pure" set, i.e.,
+ * without parameters or divs and where the convex hull of set is
+ * known to be full-dimensional.
+ */
+static struct isl_basic_set *uset_convex_hull_wrap_bounded(struct isl_set *set)
+{
+ int i;
+ struct isl_basic_set *convex_hull = NULL;
+
+ if (isl_set_n_dim(set) == 0) {
+ convex_hull = isl_basic_set_universe(isl_dim_copy(set->dim));
+ isl_set_free(set);
+ convex_hull = isl_basic_set_set_rational(convex_hull);
+ return convex_hull;
+ }
+
+ set = isl_set_set_rational(set);
+
+ if (!set)
+ goto error;
+ set = isl_set_coalesce(set);
+ if (!set)
+ goto error;
+ if (set->n == 1) {
+ convex_hull = isl_basic_set_copy(set->p[0]);
+ isl_set_free(set);
+ return convex_hull;
+ }
+ if (isl_set_n_dim(set) == 1)
+ return convex_hull_1d(set);
+
+ return uset_convex_hull_wrap(set);
+error:
+ isl_set_free(set);
+ return NULL;
+}
+
+/* Compute the convex hull of set "set" with affine hull "affine_hull",
+ * We first remove the equalities (transforming the set), compute the
+ * convex hull of the transformed set and then add the equalities back
+ * (after performing the inverse transformation.
+ */
+static struct isl_basic_set *modulo_affine_hull(struct isl_ctx *ctx,
+ struct isl_set *set, struct isl_basic_set *affine_hull)
+{
+ struct isl_mat *T;
+ struct isl_mat *T2;
+ struct isl_basic_set *dummy;
+ struct isl_basic_set *convex_hull;
+
+ dummy = isl_basic_set_remove_equalities(
+ isl_basic_set_copy(affine_hull), &T, &T2);
+ if (!dummy)
+ goto error;
+ isl_basic_set_free(dummy);
+ set = isl_set_preimage(set, T);
+ convex_hull = uset_convex_hull(set);
+ convex_hull = isl_basic_set_preimage(convex_hull, T2);
+ convex_hull = isl_basic_set_intersect(convex_hull, affine_hull);
+ return convex_hull;
+error:
+ isl_basic_set_free(affine_hull);
+ isl_set_free(set);
+ return NULL;
+}
+
+/* Compute the convex hull of a map.
+ *
+ * The implementation was inspired by "Extended Convex Hull" by Fukuda et al.,
+ * specifically, the wrapping of facets to obtain new facets.
+ */
+struct isl_basic_map *isl_map_convex_hull(struct isl_map *map)
+{
+ struct isl_basic_set *bset;
+ struct isl_basic_map *model = NULL;
+ struct isl_basic_set *affine_hull = NULL;
+ struct isl_basic_map *convex_hull = NULL;
+ struct isl_set *set = NULL;
+ struct isl_ctx *ctx;
+
+ if (!map)
+ goto error;
+
+ ctx = map->ctx;
+ if (map->n == 0) {
+ convex_hull = isl_basic_map_empty_like_map(map);
+ isl_map_free(map);
+ return convex_hull;
+ }
+
+ map = isl_map_detect_equalities(map);
+ map = isl_map_align_divs(map);
+ model = isl_basic_map_copy(map->p[0]);
+ set = isl_map_underlying_set(map);
+ if (!set)
+ goto error;
+
+ affine_hull = isl_set_affine_hull(isl_set_copy(set));
+ if (!affine_hull)
+ goto error;
+ if (affine_hull->n_eq != 0)
+ bset = modulo_affine_hull(ctx, set, affine_hull);
+ else {
+ isl_basic_set_free(affine_hull);
+ bset = uset_convex_hull(set);
+ }
+
+ convex_hull = isl_basic_map_overlying_set(bset, model);
+
+ ISL_F_SET(convex_hull, ISL_BASIC_MAP_NO_IMPLICIT);
+ ISL_F_SET(convex_hull, ISL_BASIC_MAP_ALL_EQUALITIES);
+ ISL_F_CLR(convex_hull, ISL_BASIC_MAP_RATIONAL);
+ return convex_hull;
+error:
+ isl_set_free(set);
+ isl_basic_map_free(model);
+ return NULL;
+}
+
+struct isl_basic_set *isl_set_convex_hull(struct isl_set *set)
+{
+ return (struct isl_basic_set *)
+ isl_map_convex_hull((struct isl_map *)set);
+}
+
+struct sh_data_entry {
+ struct isl_hash_table *table;
+ struct isl_tab *tab;
+};
+
+/* Holds the data needed during the simple hull computation.
+ * In particular,
+ * n the number of basic sets in the original set
+ * hull_table a hash table of already computed constraints
+ * in the simple hull
+ * p for each basic set,
+ * table a hash table of the constraints
+ * tab the tableau corresponding to the basic set
+ */
+struct sh_data {
+ struct isl_ctx *ctx;
+ unsigned n;
+ struct isl_hash_table *hull_table;
+ struct sh_data_entry p[0];
+};
+
+static void sh_data_free(struct sh_data *data)
+{
+ int i;
+
+ if (!data)
+ return;
+ isl_hash_table_free(data->ctx, data->hull_table);
+ for (i = 0; i < data->n; ++i) {
+ isl_hash_table_free(data->ctx, data->p[i].table);
+ isl_tab_free(data->p[i].tab);
+ }
+ free(data);
+}
+
+struct ineq_cmp_data {
+ unsigned len;
+ isl_int *p;
+};
+
+static int has_ineq(const void *entry, const void *val)
+{
+ isl_int *row = (isl_int *)entry;
+ struct ineq_cmp_data *v = (struct ineq_cmp_data *)val;
+
+ return isl_seq_eq(row + 1, v->p + 1, v->len) ||
+ isl_seq_is_neg(row + 1, v->p + 1, v->len);
+}
+
+static int hash_ineq(struct isl_ctx *ctx, struct isl_hash_table *table,
+ isl_int *ineq, unsigned len)
+{
+ uint32_t c_hash;
+ struct ineq_cmp_data v;
+ struct isl_hash_table_entry *entry;
+
+ v.len = len;
+ v.p = ineq;
+ c_hash = isl_seq_hash(ineq + 1, len, isl_hash_init());
+ entry = isl_hash_table_find(ctx, table, c_hash, has_ineq, &v, 1);
+ if (!entry)
+ return - 1;
+ entry->data = ineq;
+ return 0;
+}
+
+/* Fill hash table "table" with the constraints of "bset".
+ * Equalities are added as two inequalities.
+ * The value in the hash table is a pointer to the (in)equality of "bset".
+ */
+static int hash_basic_set(struct isl_hash_table *table,
+ struct isl_basic_set *bset)
+{
+ int i, j;
+ unsigned dim = isl_basic_set_total_dim(bset);
+
+ for (i = 0; i < bset->n_eq; ++i) {
+ for (j = 0; j < 2; ++j) {
+ isl_seq_neg(bset->eq[i], bset->eq[i], 1 + dim);
+ if (hash_ineq(bset->ctx, table, bset->eq[i], dim) < 0)
+ return -1;
+ }
+ }
+ for (i = 0; i < bset->n_ineq; ++i) {
+ if (hash_ineq(bset->ctx, table, bset->ineq[i], dim) < 0)
+ return -1;
+ }
+ return 0;
+}
+
+static struct sh_data *sh_data_alloc(struct isl_set *set, unsigned n_ineq)
+{
+ struct sh_data *data;
+ int i;
+
+ data = isl_calloc(set->ctx, struct sh_data,
+ sizeof(struct sh_data) + set->n * sizeof(struct sh_data_entry));
+ if (!data)
+ return NULL;
+ data->ctx = set->ctx;
+ data->n = set->n;
+ data->hull_table = isl_hash_table_alloc(set->ctx, n_ineq);
+ if (!data->hull_table)
+ goto error;
+ for (i = 0; i < set->n; ++i) {
+ data->p[i].table = isl_hash_table_alloc(set->ctx,
+ 2 * set->p[i]->n_eq + set->p[i]->n_ineq);
+ if (!data->p[i].table)
+ goto error;
+ if (hash_basic_set(data->p[i].table, set->p[i]) < 0)
+ goto error;
+ }
+ return data;
+error:
+ sh_data_free(data);
+ return NULL;
+}
+
+/* Check if inequality "ineq" is a bound for basic set "j" or if
+ * it can be relaxed (by increasing the constant term) to become
+ * a bound for that basic set. In the latter case, the constant
+ * term is updated.
+ * Return 1 if "ineq" is a bound
+ * 0 if "ineq" may attain arbitrarily small values on basic set "j"
+ * -1 if some error occurred
+ */
+static int is_bound(struct sh_data *data, struct isl_set *set, int j,
+ isl_int *ineq)
+{
+ enum isl_lp_result res;
+ isl_int opt;
+
+ if (!data->p[j].tab) {
+ data->p[j].tab = isl_tab_from_basic_set(set->p[j]);
+ if (!data->p[j].tab)
+ return -1;
+ }
+
+ isl_int_init(opt);
+
+ res = isl_tab_min(data->p[j].tab, ineq, data->ctx->one,
+ &opt, NULL, 0);
+ if (res == isl_lp_ok && isl_int_is_neg(opt))
+ isl_int_sub(ineq[0], ineq[0], opt);
+
+ isl_int_clear(opt);
+
+ return res == isl_lp_ok ? 1 :
+ res == isl_lp_unbounded ? 0 : -1;
+}
+
+/* Check if inequality "ineq" from basic set "i" can be relaxed to
+ * become a bound on the whole set. If so, add the (relaxed) inequality
+ * to "hull".
+ *
+ * We first check if "hull" already contains a translate of the inequality.
+ * If so, we are done.
+ * Then, we check if any of the previous basic sets contains a translate
+ * of the inequality. If so, then we have already considered this
+ * inequality and we are done.
+ * Otherwise, for each basic set other than "i", we check if the inequality
+ * is a bound on the basic set.
+ * For previous basic sets, we know that they do not contain a translate
+ * of the inequality, so we directly call is_bound.
+ * For following basic sets, we first check if a translate of the
+ * inequality appears in its description and if so directly update
+ * the inequality accordingly.
+ */
+static struct isl_basic_set *add_bound(struct isl_basic_set *hull,
+ struct sh_data *data, struct isl_set *set, int i, isl_int *ineq)
+{
+ uint32_t c_hash;
+ struct ineq_cmp_data v;
+ struct isl_hash_table_entry *entry;
+ int j, k;
+
+ if (!hull)
+ return NULL;
+
+ v.len = isl_basic_set_total_dim(hull);
+ v.p = ineq;
+ c_hash = isl_seq_hash(ineq + 1, v.len, isl_hash_init());
+
+ entry = isl_hash_table_find(hull->ctx, data->hull_table, c_hash,
+ has_ineq, &v, 0);
+ if (entry)
+ return hull;
+
+ for (j = 0; j < i; ++j) {
+ entry = isl_hash_table_find(hull->ctx, data->p[j].table,
+ c_hash, has_ineq, &v, 0);
+ if (entry)
+ break;
+ }
+ if (j < i)
+ return hull;
+
+ k = isl_basic_set_alloc_inequality(hull);
+ isl_seq_cpy(hull->ineq[k], ineq, 1 + v.len);
+ if (k < 0)
+ goto error;
+
+ for (j = 0; j < i; ++j) {
+ int bound;
+ bound = is_bound(data, set, j, hull->ineq[k]);
+ if (bound < 0)
+ goto error;
+ if (!bound)
+ break;
+ }
+ if (j < i) {
+ isl_basic_set_free_inequality(hull, 1);
+ return hull;
+ }
+
+ for (j = i + 1; j < set->n; ++j) {
+ int bound, neg;
+ isl_int *ineq_j;
+ entry = isl_hash_table_find(hull->ctx, data->p[j].table,
+ c_hash, has_ineq, &v, 0);
+ if (entry) {
+ ineq_j = entry->data;
+ neg = isl_seq_is_neg(ineq_j + 1,
+ hull->ineq[k] + 1, v.len);
+ if (neg)
+ isl_int_neg(ineq_j[0], ineq_j[0]);
+ if (isl_int_gt(ineq_j[0], hull->ineq[k][0]))
+ isl_int_set(hull->ineq[k][0], ineq_j[0]);
+ if (neg)
+ isl_int_neg(ineq_j[0], ineq_j[0]);
+ continue;
+ }
+ bound = is_bound(data, set, j, hull->ineq[k]);
+ if (bound < 0)
+ goto error;
+ if (!bound)
+ break;
+ }
+ if (j < set->n) {
+ isl_basic_set_free_inequality(hull, 1);
+ return hull;
+ }
+
+ entry = isl_hash_table_find(hull->ctx, data->hull_table, c_hash,
+ has_ineq, &v, 1);
+ if (!entry)
+ goto error;
+ entry->data = hull->ineq[k];
+
+ return hull;
+error:
+ isl_basic_set_free(hull);
+ return NULL;
+}
+
+/* Check if any inequality from basic set "i" can be relaxed to
+ * become a bound on the whole set. If so, add the (relaxed) inequality
+ * to "hull".
+ */
+static struct isl_basic_set *add_bounds(struct isl_basic_set *bset,
+ struct sh_data *data, struct isl_set *set, int i)
+{
+ int j, k;
+ unsigned dim = isl_basic_set_total_dim(bset);
+
+ for (j = 0; j < set->p[i]->n_eq; ++j) {
+ for (k = 0; k < 2; ++k) {
+ isl_seq_neg(set->p[i]->eq[j], set->p[i]->eq[j], 1+dim);
+ add_bound(bset, data, set, i, set->p[i]->eq[j]);
+ }
+ }
+ for (j = 0; j < set->p[i]->n_ineq; ++j)
+ add_bound(bset, data, set, i, set->p[i]->ineq[j]);
+ return bset;
+}
+
+/* Compute a superset of the convex hull of set that is described
+ * by only translates of the constraints in the constituents of set.
+ */
+static struct isl_basic_set *uset_simple_hull(struct isl_set *set)
+{
+ struct sh_data *data = NULL;
+ struct isl_basic_set *hull = NULL;
+ unsigned n_ineq;
+ int i, j;
+
+ if (!set)
+ return NULL;
+
+ n_ineq = 0;
+ for (i = 0; i < set->n; ++i) {
+ if (!set->p[i])
+ goto error;
+ n_ineq += 2 * set->p[i]->n_eq + set->p[i]->n_ineq;
+ }
+
+ hull = isl_basic_set_alloc_dim(isl_dim_copy(set->dim), 0, 0, n_ineq);
+ if (!hull)
+ goto error;
+
+ data = sh_data_alloc(set, n_ineq);
+ if (!data)
+ goto error;
+
+ for (i = 0; i < set->n; ++i)
+ hull = add_bounds(hull, data, set, i);
+
+ sh_data_free(data);
+ isl_set_free(set);
+
+ return hull;
+error:
+ sh_data_free(data);
+ isl_basic_set_free(hull);
+ isl_set_free(set);
+ return NULL;
+}