2 * Copyright 2010 INRIA Saclay
4 * Use of this software is governed by the GNU LGPLv2.1 license
6 * Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
7 * Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
12 #include "isl_map_private.h"
14 #include <isl_dim_private.h>
16 #include <isl_union_map.h>
18 int isl_map_is_transitively_closed(__isl_keep isl_map *map)
23 map2 = isl_map_apply_range(isl_map_copy(map), isl_map_copy(map));
24 closed = isl_map_is_subset(map2, map);
30 int isl_union_map_is_transitively_closed(__isl_keep isl_union_map *umap)
35 umap2 = isl_union_map_apply_range(isl_union_map_copy(umap),
36 isl_union_map_copy(umap));
37 closed = isl_union_map_is_subset(umap2, umap);
38 isl_union_map_free(umap2);
43 /* Given a map that represents a path with the length of the path
44 * encoded as the difference between the last output coordindate
45 * and the last input coordinate, set this length to either
46 * exactly "length" (if "exactly" is set) or at least "length"
47 * (if "exactly" is not set).
49 static __isl_give isl_map *set_path_length(__isl_take isl_map *map,
50 int exactly, int length)
53 struct isl_basic_map *bmap;
62 dim = isl_map_get_dim(map);
63 d = isl_dim_size(dim, isl_dim_in);
64 nparam = isl_dim_size(dim, isl_dim_param);
65 bmap = isl_basic_map_alloc_dim(dim, 0, 1, 1);
67 k = isl_basic_map_alloc_equality(bmap);
70 k = isl_basic_map_alloc_inequality(bmap);
75 isl_seq_clr(c, 1 + isl_basic_map_total_dim(bmap));
76 isl_int_set_si(c[0], -length);
77 isl_int_set_si(c[1 + nparam + d - 1], -1);
78 isl_int_set_si(c[1 + nparam + d + d - 1], 1);
80 bmap = isl_basic_map_finalize(bmap);
81 map = isl_map_intersect(map, isl_map_from_basic_map(bmap));
85 isl_basic_map_free(bmap);
90 /* Check whether the overapproximation of the power of "map" is exactly
91 * the power of "map". Let R be "map" and A_k the overapproximation.
92 * The approximation is exact if
95 * A_k = A_{k-1} \circ R k >= 2
97 * Since A_k is known to be an overapproximation, we only need to check
100 * A_k \subset A_{k-1} \circ R k >= 2
102 * In practice, "app" has an extra input and output coordinate
103 * to encode the length of the path. So, we first need to add
104 * this coordinate to "map" and set the length of the path to
107 static int check_power_exactness(__isl_take isl_map *map,
108 __isl_take isl_map *app)
114 map = isl_map_add(map, isl_dim_in, 1);
115 map = isl_map_add(map, isl_dim_out, 1);
116 map = set_path_length(map, 1, 1);
118 app_1 = set_path_length(isl_map_copy(app), 1, 1);
120 exact = isl_map_is_subset(app_1, map);
123 if (!exact || exact < 0) {
129 app_1 = set_path_length(isl_map_copy(app), 0, 1);
130 app_2 = set_path_length(app, 0, 2);
131 app_1 = isl_map_apply_range(map, app_1);
133 exact = isl_map_is_subset(app_2, app_1);
141 /* Check whether the overapproximation of the power of "map" is exactly
142 * the power of "map", possibly after projecting out the power (if "project"
145 * If "project" is set and if "steps" can only result in acyclic paths,
148 * A = R \cup (A \circ R)
150 * where A is the overapproximation with the power projected out, i.e.,
151 * an overapproximation of the transitive closure.
152 * More specifically, since A is known to be an overapproximation, we check
154 * A \subset R \cup (A \circ R)
156 * Otherwise, we check if the power is exact.
158 * Note that "app" has an extra input and output coordinate to encode
159 * the length of the part. If we are only interested in the transitive
160 * closure, then we can simply project out these coordinates first.
162 static int check_exactness(__isl_take isl_map *map, __isl_take isl_map *app,
170 return check_power_exactness(map, app);
172 d = isl_map_dim(map, isl_dim_in);
173 app = set_path_length(app, 0, 1);
174 app = isl_map_project_out(app, isl_dim_in, d, 1);
175 app = isl_map_project_out(app, isl_dim_out, d, 1);
177 app = isl_map_reset_dim(app, isl_map_get_dim(map));
179 test = isl_map_apply_range(isl_map_copy(map), isl_map_copy(app));
180 test = isl_map_union(test, isl_map_copy(map));
182 exact = isl_map_is_subset(app, test);
193 * The transitive closure implementation is based on the paper
194 * "Computing the Transitive Closure of a Union of Affine Integer
195 * Tuple Relations" by Anna Beletska, Denis Barthou, Wlodzimierz Bielecki and
199 /* Given a set of n offsets v_i (the rows of "steps"), construct a relation
200 * of the given dimension specification (Z^{n+1} -> Z^{n+1})
201 * that maps an element x to any element that can be reached
202 * by taking a non-negative number of steps along any of
203 * the extended offsets v'_i = [v_i 1].
206 * { [x] -> [y] : exists k_i >= 0, y = x + \sum_i k_i v'_i }
208 * For any element in this relation, the number of steps taken
209 * is equal to the difference in the final coordinates.
211 static __isl_give isl_map *path_along_steps(__isl_take isl_dim *dim,
212 __isl_keep isl_mat *steps)
215 struct isl_basic_map *path = NULL;
223 d = isl_dim_size(dim, isl_dim_in);
225 nparam = isl_dim_size(dim, isl_dim_param);
227 path = isl_basic_map_alloc_dim(isl_dim_copy(dim), n, d, n);
229 for (i = 0; i < n; ++i) {
230 k = isl_basic_map_alloc_div(path);
233 isl_assert(steps->ctx, i == k, goto error);
234 isl_int_set_si(path->div[k][0], 0);
237 for (i = 0; i < d; ++i) {
238 k = isl_basic_map_alloc_equality(path);
241 isl_seq_clr(path->eq[k], 1 + isl_basic_map_total_dim(path));
242 isl_int_set_si(path->eq[k][1 + nparam + i], 1);
243 isl_int_set_si(path->eq[k][1 + nparam + d + i], -1);
245 for (j = 0; j < n; ++j)
246 isl_int_set_si(path->eq[k][1 + nparam + 2 * d + j], 1);
248 for (j = 0; j < n; ++j)
249 isl_int_set(path->eq[k][1 + nparam + 2 * d + j],
253 for (i = 0; i < n; ++i) {
254 k = isl_basic_map_alloc_inequality(path);
257 isl_seq_clr(path->ineq[k], 1 + isl_basic_map_total_dim(path));
258 isl_int_set_si(path->ineq[k][1 + nparam + 2 * d + i], 1);
263 path = isl_basic_map_simplify(path);
264 path = isl_basic_map_finalize(path);
265 return isl_map_from_basic_map(path);
268 isl_basic_map_free(path);
277 /* Check whether the parametric constant term of constraint c is never
278 * positive in "bset".
280 static int parametric_constant_never_positive(__isl_keep isl_basic_set *bset,
281 isl_int *c, int *div_purity)
290 n_div = isl_basic_set_dim(bset, isl_dim_div);
291 d = isl_basic_set_dim(bset, isl_dim_set);
292 nparam = isl_basic_set_dim(bset, isl_dim_param);
294 bset = isl_basic_set_copy(bset);
295 bset = isl_basic_set_cow(bset);
296 bset = isl_basic_set_extend_constraints(bset, 0, 1);
297 k = isl_basic_set_alloc_inequality(bset);
300 isl_seq_clr(bset->ineq[k], 1 + isl_basic_set_total_dim(bset));
301 isl_seq_cpy(bset->ineq[k], c, 1 + nparam);
302 for (i = 0; i < n_div; ++i) {
303 if (div_purity[i] != PURE_PARAM)
305 isl_int_set(bset->ineq[k][1 + nparam + d + i],
306 c[1 + nparam + d + i]);
308 isl_int_sub_ui(bset->ineq[k][0], bset->ineq[k][0], 1);
309 empty = isl_basic_set_is_empty(bset);
310 isl_basic_set_free(bset);
314 isl_basic_set_free(bset);
318 /* Return PURE_PARAM if only the coefficients of the parameters are non-zero.
319 * Return PURE_VAR if only the coefficients of the set variables are non-zero.
320 * Return MIXED if only the coefficients of the parameters and the set
321 * variables are non-zero and if moreover the parametric constant
322 * can never attain positive values.
323 * Return IMPURE otherwise.
325 static int purity(__isl_keep isl_basic_set *bset, isl_int *c, int *div_purity,
335 n_div = isl_basic_set_dim(bset, isl_dim_div);
336 d = isl_basic_set_dim(bset, isl_dim_set);
337 nparam = isl_basic_set_dim(bset, isl_dim_param);
339 for (i = 0; i < n_div; ++i) {
340 if (isl_int_is_zero(c[1 + nparam + d + i]))
342 switch (div_purity[i]) {
343 case PURE_PARAM: p = 1; break;
344 case PURE_VAR: v = 1; break;
345 default: return IMPURE;
348 if (!p && isl_seq_first_non_zero(c + 1, nparam) == -1)
350 if (!v && isl_seq_first_non_zero(c + 1 + nparam, d) == -1)
353 empty = parametric_constant_never_positive(bset, c, div_purity);
354 if (eq && empty >= 0 && !empty) {
355 isl_seq_neg(c, c, 1 + nparam + d + n_div);
356 empty = parametric_constant_never_positive(bset, c, div_purity);
359 return empty < 0 ? -1 : empty ? MIXED : IMPURE;
362 /* Return an array of integers indicating the type of each div in bset.
363 * If the div is (recursively) defined in terms of only the parameters,
364 * then the type is PURE_PARAM.
365 * If the div is (recursively) defined in terms of only the set variables,
366 * then the type is PURE_VAR.
367 * Otherwise, the type is IMPURE.
369 static __isl_give int *get_div_purity(__isl_keep isl_basic_set *bset)
380 n_div = isl_basic_set_dim(bset, isl_dim_div);
381 d = isl_basic_set_dim(bset, isl_dim_set);
382 nparam = isl_basic_set_dim(bset, isl_dim_param);
384 div_purity = isl_alloc_array(bset->ctx, int, n_div);
388 for (i = 0; i < bset->n_div; ++i) {
390 if (isl_int_is_zero(bset->div[i][0])) {
391 div_purity[i] = IMPURE;
394 if (isl_seq_first_non_zero(bset->div[i] + 2, nparam) != -1)
396 if (isl_seq_first_non_zero(bset->div[i] + 2 + nparam, d) != -1)
398 for (j = 0; j < i; ++j) {
399 if (isl_int_is_zero(bset->div[i][2 + nparam + d + j]))
401 switch (div_purity[j]) {
402 case PURE_PARAM: p = 1; break;
403 case PURE_VAR: v = 1; break;
404 default: p = v = 1; break;
407 div_purity[i] = v ? p ? IMPURE : PURE_VAR : PURE_PARAM;
413 /* Given a path with the as yet unconstrained length at position "pos",
414 * check if setting the length to zero results in only the identity
417 int empty_path_is_identity(__isl_keep isl_basic_map *path, unsigned pos)
419 isl_basic_map *test = NULL;
420 isl_basic_map *id = NULL;
424 test = isl_basic_map_copy(path);
425 test = isl_basic_map_extend_constraints(test, 1, 0);
426 k = isl_basic_map_alloc_equality(test);
429 isl_seq_clr(test->eq[k], 1 + isl_basic_map_total_dim(test));
430 isl_int_set_si(test->eq[k][pos], 1);
431 id = isl_basic_map_identity(isl_dim_domain(isl_basic_map_get_dim(path)));
432 is_id = isl_basic_map_is_equal(test, id);
433 isl_basic_map_free(test);
434 isl_basic_map_free(id);
437 isl_basic_map_free(test);
441 __isl_give isl_basic_map *add_delta_constraints(__isl_take isl_basic_map *path,
442 __isl_keep isl_basic_set *delta, unsigned off, unsigned nparam,
443 unsigned d, int *div_purity, int eq)
446 int n = eq ? delta->n_eq : delta->n_ineq;
447 isl_int **delta_c = eq ? delta->eq : delta->ineq;
450 n_div = isl_basic_set_dim(delta, isl_dim_div);
452 for (i = 0; i < n; ++i) {
454 int p = purity(delta, delta_c[i], div_purity, eq);
459 if (eq && p != MIXED) {
460 k = isl_basic_map_alloc_equality(path);
461 path_c = path->eq[k];
463 k = isl_basic_map_alloc_inequality(path);
464 path_c = path->ineq[k];
468 isl_seq_clr(path_c, 1 + isl_basic_map_total_dim(path));
470 isl_seq_cpy(path_c + off,
471 delta_c[i] + 1 + nparam, d);
472 isl_int_set(path_c[off + d], delta_c[i][0]);
473 } else if (p == PURE_PARAM) {
474 isl_seq_cpy(path_c, delta_c[i], 1 + nparam);
476 isl_seq_cpy(path_c + off,
477 delta_c[i] + 1 + nparam, d);
478 isl_seq_cpy(path_c, delta_c[i], 1 + nparam);
480 isl_seq_cpy(path_c + off - n_div,
481 delta_c[i] + 1 + nparam + d, n_div);
486 isl_basic_map_free(path);
490 /* Given a set of offsets "delta", construct a relation of the
491 * given dimension specification (Z^{n+1} -> Z^{n+1}) that
492 * is an overapproximation of the relations that
493 * maps an element x to any element that can be reached
494 * by taking a non-negative number of steps along any of
495 * the elements in "delta".
496 * That is, construct an approximation of
498 * { [x] -> [y] : exists f \in \delta, k \in Z :
499 * y = x + k [f, 1] and k >= 0 }
501 * For any element in this relation, the number of steps taken
502 * is equal to the difference in the final coordinates.
504 * In particular, let delta be defined as
506 * \delta = [p] -> { [x] : A x + a >= and B p + b >= 0 and
507 * C x + C'p + c >= 0 and
508 * D x + D'p + d >= 0 }
510 * where the constraints C x + C'p + c >= 0 are such that the parametric
511 * constant term of each constraint j, "C_j x + C'_j p + c_j",
512 * can never attain positive values, then the relation is constructed as
514 * { [x] -> [y] : exists [f, k] \in Z^{n+1} : y = x + f and
515 * A f + k a >= 0 and B p + b >= 0 and
516 * C f + C'p + c >= 0 and k >= 1 }
517 * union { [x] -> [x] }
519 * If the zero-length paths happen to correspond exactly to the identity
520 * mapping, then we return
522 * { [x] -> [y] : exists [f, k] \in Z^{n+1} : y = x + f and
523 * A f + k a >= 0 and B p + b >= 0 and
524 * C f + C'p + c >= 0 and k >= 0 }
528 * Existentially quantified variables in \delta are handled by
529 * classifying them as independent of the parameters, purely
530 * parameter dependent and others. Constraints containing
531 * any of the other existentially quantified variables are removed.
532 * This is safe, but leads to an additional overapproximation.
534 static __isl_give isl_map *path_along_delta(__isl_take isl_dim *dim,
535 __isl_take isl_basic_set *delta)
537 isl_basic_map *path = NULL;
544 int *div_purity = NULL;
548 n_div = isl_basic_set_dim(delta, isl_dim_div);
549 d = isl_basic_set_dim(delta, isl_dim_set);
550 nparam = isl_basic_set_dim(delta, isl_dim_param);
551 path = isl_basic_map_alloc_dim(isl_dim_copy(dim), n_div + d + 1,
552 d + 1 + delta->n_eq, delta->n_eq + delta->n_ineq + 1);
553 off = 1 + nparam + 2 * (d + 1) + n_div;
555 for (i = 0; i < n_div + d + 1; ++i) {
556 k = isl_basic_map_alloc_div(path);
559 isl_int_set_si(path->div[k][0], 0);
562 for (i = 0; i < d + 1; ++i) {
563 k = isl_basic_map_alloc_equality(path);
566 isl_seq_clr(path->eq[k], 1 + isl_basic_map_total_dim(path));
567 isl_int_set_si(path->eq[k][1 + nparam + i], 1);
568 isl_int_set_si(path->eq[k][1 + nparam + d + 1 + i], -1);
569 isl_int_set_si(path->eq[k][off + i], 1);
572 div_purity = get_div_purity(delta);
576 path = add_delta_constraints(path, delta, off, nparam, d, div_purity, 1);
577 path = add_delta_constraints(path, delta, off, nparam, d, div_purity, 0);
579 is_id = empty_path_is_identity(path, off + d);
583 k = isl_basic_map_alloc_inequality(path);
586 isl_seq_clr(path->ineq[k], 1 + isl_basic_map_total_dim(path));
588 isl_int_set_si(path->ineq[k][0], -1);
589 isl_int_set_si(path->ineq[k][off + d], 1);
592 isl_basic_set_free(delta);
593 path = isl_basic_map_finalize(path);
596 return isl_map_from_basic_map(path);
598 return isl_basic_map_union(path,
599 isl_basic_map_identity(isl_dim_domain(dim)));
603 isl_basic_set_free(delta);
604 isl_basic_map_free(path);
608 /* Given a dimension specification Z^{n+1} -> Z^{n+1} and a parameter "param",
609 * construct a map that equates the parameter to the difference
610 * in the final coordinates and imposes that this difference is positive.
613 * { [x,x_s] -> [y,y_s] : k = y_s - x_s > 0 }
615 static __isl_give isl_map *equate_parameter_to_length(__isl_take isl_dim *dim,
618 struct isl_basic_map *bmap;
623 d = isl_dim_size(dim, isl_dim_in);
624 nparam = isl_dim_size(dim, isl_dim_param);
625 bmap = isl_basic_map_alloc_dim(dim, 0, 1, 1);
626 k = isl_basic_map_alloc_equality(bmap);
629 isl_seq_clr(bmap->eq[k], 1 + isl_basic_map_total_dim(bmap));
630 isl_int_set_si(bmap->eq[k][1 + param], -1);
631 isl_int_set_si(bmap->eq[k][1 + nparam + d - 1], -1);
632 isl_int_set_si(bmap->eq[k][1 + nparam + d + d - 1], 1);
634 k = isl_basic_map_alloc_inequality(bmap);
637 isl_seq_clr(bmap->ineq[k], 1 + isl_basic_map_total_dim(bmap));
638 isl_int_set_si(bmap->ineq[k][1 + param], 1);
639 isl_int_set_si(bmap->ineq[k][0], -1);
641 bmap = isl_basic_map_finalize(bmap);
642 return isl_map_from_basic_map(bmap);
644 isl_basic_map_free(bmap);
648 /* Check whether "path" is acyclic, where the last coordinates of domain
649 * and range of path encode the number of steps taken.
650 * That is, check whether
652 * { d | d = y - x and (x,y) in path }
654 * does not contain any element with positive last coordinate (positive length)
655 * and zero remaining coordinates (cycle).
657 static int is_acyclic(__isl_take isl_map *path)
662 struct isl_set *delta;
664 delta = isl_map_deltas(path);
665 dim = isl_set_dim(delta, isl_dim_set);
666 for (i = 0; i < dim; ++i) {
668 delta = isl_set_lower_bound_si(delta, isl_dim_set, i, 1);
670 delta = isl_set_fix_si(delta, isl_dim_set, i, 0);
673 acyclic = isl_set_is_empty(delta);
679 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
680 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
681 * construct a map that is an overapproximation of the map
682 * that takes an element from the space D \times Z to another
683 * element from the same space, such that the first n coordinates of the
684 * difference between them is a sum of differences between images
685 * and pre-images in one of the R_i and such that the last coordinate
686 * is equal to the number of steps taken.
689 * \Delta_i = { y - x | (x, y) in R_i }
691 * then the constructed map is an overapproximation of
693 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
694 * d = (\sum_i k_i \delta_i, \sum_i k_i) }
696 * The elements of the singleton \Delta_i's are collected as the
697 * rows of the steps matrix. For all these \Delta_i's together,
698 * a single path is constructed.
699 * For each of the other \Delta_i's, we compute an overapproximation
700 * of the paths along elements of \Delta_i.
701 * Since each of these paths performs an addition, composition is
702 * symmetric and we can simply compose all resulting paths in any order.
704 static __isl_give isl_map *construct_extended_path(__isl_take isl_dim *dim,
705 __isl_keep isl_map *map, int *project)
707 struct isl_mat *steps = NULL;
708 struct isl_map *path = NULL;
712 d = isl_map_dim(map, isl_dim_in);
714 path = isl_map_identity(isl_dim_domain(isl_dim_copy(dim)));
716 steps = isl_mat_alloc(map->ctx, map->n, d);
721 for (i = 0; i < map->n; ++i) {
722 struct isl_basic_set *delta;
724 delta = isl_basic_map_deltas(isl_basic_map_copy(map->p[i]));
726 for (j = 0; j < d; ++j) {
729 fixed = isl_basic_set_fast_dim_is_fixed(delta, j,
732 isl_basic_set_free(delta);
741 path = isl_map_apply_range(path,
742 path_along_delta(isl_dim_copy(dim), delta));
743 path = isl_map_coalesce(path);
745 isl_basic_set_free(delta);
752 path = isl_map_apply_range(path,
753 path_along_steps(isl_dim_copy(dim), steps));
756 if (project && *project) {
757 *project = is_acyclic(isl_map_copy(path));
772 static int isl_set_overlaps(__isl_keep isl_set *set1, __isl_keep isl_set *set2)
777 if (!isl_dim_tuple_match(set1->dim, isl_dim_set, set2->dim, isl_dim_set))
780 i = isl_set_intersect(isl_set_copy(set1), isl_set_copy(set2));
781 no_overlap = isl_set_is_empty(i);
784 return no_overlap < 0 ? -1 : !no_overlap;
787 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
788 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
789 * construct a map that is an overapproximation of the map
790 * that takes an element from the dom R \times Z to an
791 * element from ran R \times Z, such that the first n coordinates of the
792 * difference between them is a sum of differences between images
793 * and pre-images in one of the R_i and such that the last coordinate
794 * is equal to the number of steps taken.
797 * \Delta_i = { y - x | (x, y) in R_i }
799 * then the constructed map is an overapproximation of
801 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
802 * d = (\sum_i k_i \delta_i, \sum_i k_i) and
803 * x in dom R and x + d in ran R and
806 static __isl_give isl_map *construct_component(__isl_take isl_dim *dim,
807 __isl_keep isl_map *map, int *exact, int project)
809 struct isl_set *domain = NULL;
810 struct isl_set *range = NULL;
811 struct isl_map *app = NULL;
812 struct isl_map *path = NULL;
814 domain = isl_map_domain(isl_map_copy(map));
815 domain = isl_set_coalesce(domain);
816 range = isl_map_range(isl_map_copy(map));
817 range = isl_set_coalesce(range);
818 if (!isl_set_overlaps(domain, range)) {
819 isl_set_free(domain);
823 map = isl_map_copy(map);
824 map = isl_map_add(map, isl_dim_in, 1);
825 map = isl_map_add(map, isl_dim_out, 1);
826 map = set_path_length(map, 1, 1);
829 app = isl_map_from_domain_and_range(domain, range);
830 app = isl_map_add(app, isl_dim_in, 1);
831 app = isl_map_add(app, isl_dim_out, 1);
833 path = construct_extended_path(isl_dim_copy(dim), map,
834 exact && *exact ? &project : NULL);
835 app = isl_map_intersect(app, path);
837 if (exact && *exact &&
838 (*exact = check_exactness(isl_map_copy(map), isl_map_copy(app),
843 app = set_path_length(app, 0, 1);
851 /* Call construct_component and, if "project" is set, project out
852 * the final coordinates.
854 static __isl_give isl_map *construct_projected_component(
855 __isl_take isl_dim *dim,
856 __isl_keep isl_map *map, int *exact, int project)
863 d = isl_dim_size(dim, isl_dim_in);
865 app = construct_component(dim, map, exact, project);
867 app = isl_map_project_out(app, isl_dim_in, d - 1, 1);
868 app = isl_map_project_out(app, isl_dim_out, d - 1, 1);
873 /* Compute an extended version, i.e., with path lengths, of
874 * an overapproximation of the transitive closure of "bmap"
875 * with path lengths greater than or equal to zero and with
876 * domain and range equal to "dom".
878 static __isl_give isl_map *q_closure(__isl_take isl_dim *dim,
879 __isl_take isl_set *dom, __isl_keep isl_basic_map *bmap, int *exact)
886 dom = isl_set_add(dom, isl_dim_set, 1);
887 app = isl_map_from_domain_and_range(dom, isl_set_copy(dom));
888 map = isl_map_from_basic_map(isl_basic_map_copy(bmap));
889 path = construct_extended_path(dim, map, &project);
890 app = isl_map_intersect(app, path);
892 if ((*exact = check_exactness(map, isl_map_copy(app), project)) < 0)
901 /* Check whether qc has any elements of length at least one
902 * with domain and/or range outside of dom and ran.
904 static int has_spurious_elements(__isl_keep isl_map *qc,
905 __isl_keep isl_set *dom, __isl_keep isl_set *ran)
911 if (!qc || !dom || !ran)
914 d = isl_map_dim(qc, isl_dim_in);
916 qc = isl_map_copy(qc);
917 qc = set_path_length(qc, 0, 1);
918 qc = isl_map_project_out(qc, isl_dim_in, d - 1, 1);
919 qc = isl_map_project_out(qc, isl_dim_out, d - 1, 1);
921 s = isl_map_domain(isl_map_copy(qc));
922 subset = isl_set_is_subset(s, dom);
931 s = isl_map_range(qc);
932 subset = isl_set_is_subset(s, ran);
935 return subset < 0 ? -1 : !subset;
944 /* For each basic map in "map", except i, check whether it combines
945 * with the transitive closure that is reflexive on C combines
946 * to the left and to the right.
950 * dom map_j \subseteq C
952 * then right[j] is set to 1. Otherwise, if
954 * ran map_i \cap dom map_j = \emptyset
956 * then right[j] is set to 0. Otherwise, composing to the right
959 * Similar, for composing to the left, we have if
961 * ran map_j \subseteq C
963 * then left[j] is set to 1. Otherwise, if
965 * dom map_i \cap ran map_j = \emptyset
967 * then left[j] is set to 0. Otherwise, composing to the left
970 * The return value is or'd with LEFT if composing to the left
971 * is possible and with RIGHT if composing to the right is possible.
973 static int composability(__isl_keep isl_set *C, int i,
974 isl_set **dom, isl_set **ran, int *left, int *right,
975 __isl_keep isl_map *map)
981 for (j = 0; j < map->n && ok; ++j) {
982 int overlaps, subset;
988 dom[j] = isl_set_from_basic_set(
989 isl_basic_map_domain(
990 isl_basic_map_copy(map->p[j])));
993 overlaps = isl_set_overlaps(ran[i], dom[j]);
999 subset = isl_set_is_subset(dom[j], C);
1011 ran[j] = isl_set_from_basic_set(
1012 isl_basic_map_range(
1013 isl_basic_map_copy(map->p[j])));
1016 overlaps = isl_set_overlaps(dom[i], ran[j]);
1022 subset = isl_set_is_subset(ran[j], C);
1036 static __isl_give isl_map *anonymize(__isl_take isl_map *map)
1038 map = isl_map_set_tuple_name(map, isl_dim_in, NULL);
1039 map = isl_map_set_tuple_name(map, isl_dim_out, NULL);
1043 /* Return a map that is a union of the basic maps in "map", except i,
1044 * composed to left and right with qc based on the entries of "left"
1047 static __isl_give isl_map *compose(__isl_keep isl_map *map, int i,
1048 __isl_take isl_map *qc, int *left, int *right)
1053 comp = isl_map_empty(isl_map_get_dim(map));
1054 for (j = 0; j < map->n; ++j) {
1060 map_j = isl_map_from_basic_map(isl_basic_map_copy(map->p[j]));
1061 map_j = anonymize(map_j);
1062 if (left && left[j])
1063 map_j = isl_map_apply_range(map_j, isl_map_copy(qc));
1064 if (right && right[j])
1065 map_j = isl_map_apply_range(isl_map_copy(qc), map_j);
1066 comp = isl_map_union(comp, map_j);
1069 comp = isl_map_compute_divs(comp);
1070 comp = isl_map_coalesce(comp);
1077 /* Compute the transitive closure of "map" incrementally by
1084 * map_i^+ \cup ((id \cup map_i^) \circ qc^+)
1088 * map_i^+ \cup (qc^+ \circ (id \cup map_i^))
1090 * depending on whether left or right are NULL.
1092 static __isl_give isl_map *compute_incremental(
1093 __isl_take isl_dim *dim, __isl_keep isl_map *map,
1094 int i, __isl_take isl_map *qc, int *left, int *right, int *exact)
1098 isl_map *rtc = NULL;
1102 isl_assert(map->ctx, left || right, goto error);
1104 map_i = isl_map_from_basic_map(isl_basic_map_copy(map->p[i]));
1105 tc = construct_projected_component(isl_dim_copy(dim), map_i,
1107 isl_map_free(map_i);
1110 qc = isl_map_transitive_closure(qc, exact);
1116 return isl_map_universe(isl_map_get_dim(map));
1119 if (!left || !right)
1120 rtc = isl_map_union(isl_map_copy(tc),
1121 isl_map_identity(isl_dim_domain(isl_map_get_dim(tc))));
1123 qc = isl_map_apply_range(rtc, qc);
1125 qc = isl_map_apply_range(qc, rtc);
1126 qc = isl_map_union(tc, qc);
1137 /* Given a map "map", try to find a basic map such that
1138 * map^+ can be computed as
1140 * map^+ = map_i^+ \cup
1141 * \bigcup_j ((map_i^+ \cup Id_C)^+ \circ map_j \circ (map_i^+ \cup Id_C))^+
1143 * with C the simple hull of the domain and range of the input map.
1144 * map_i^ \cup Id_C is computed by allowing the path lengths to be zero
1145 * and by intersecting domain and range with C.
1146 * Of course, we need to check that this is actually equal to map_i^ \cup Id_C.
1147 * Also, we only use the incremental computation if all the transitive
1148 * closures are exact and if the number of basic maps in the union,
1149 * after computing the integer divisions, is smaller than the number
1150 * of basic maps in the input map.
1152 static int incemental_on_entire_domain(__isl_keep isl_dim *dim,
1153 __isl_keep isl_map *map,
1154 isl_set **dom, isl_set **ran, int *left, int *right,
1155 __isl_give isl_map **res)
1163 C = isl_set_union(isl_map_domain(isl_map_copy(map)),
1164 isl_map_range(isl_map_copy(map)));
1165 C = isl_set_from_basic_set(isl_set_simple_hull(C));
1173 d = isl_map_dim(map, isl_dim_in);
1175 for (i = 0; i < map->n; ++i) {
1177 int exact_i, spurious;
1179 dom[i] = isl_set_from_basic_set(isl_basic_map_domain(
1180 isl_basic_map_copy(map->p[i])));
1181 ran[i] = isl_set_from_basic_set(isl_basic_map_range(
1182 isl_basic_map_copy(map->p[i])));
1183 qc = q_closure(isl_dim_copy(dim), isl_set_copy(C),
1184 map->p[i], &exact_i);
1191 spurious = has_spurious_elements(qc, dom[i], ran[i]);
1198 qc = isl_map_project_out(qc, isl_dim_in, d, 1);
1199 qc = isl_map_project_out(qc, isl_dim_out, d, 1);
1200 qc = isl_map_compute_divs(qc);
1201 for (j = 0; j < map->n; ++j)
1202 left[j] = right[j] = 1;
1203 qc = compose(map, i, qc, left, right);
1206 if (qc->n >= map->n) {
1210 *res = compute_incremental(isl_dim_copy(dim), map, i, qc,
1211 left, right, &exact_i);
1222 return *res != NULL;
1228 /* Try and compute the transitive closure of "map" as
1230 * map^+ = map_i^+ \cup
1231 * \bigcup_j ((map_i^+ \cup Id_C)^+ \circ map_j \circ (map_i^+ \cup Id_C))^+
1233 * with C either the simple hull of the domain and range of the entire
1234 * map or the simple hull of domain and range of map_i.
1236 static __isl_give isl_map *incremental_closure(__isl_take isl_dim *dim,
1237 __isl_keep isl_map *map, int *exact, int project)
1240 isl_set **dom = NULL;
1241 isl_set **ran = NULL;
1246 isl_map *res = NULL;
1249 return construct_projected_component(dim, map, exact, project);
1254 return construct_projected_component(dim, map, exact, project);
1256 d = isl_map_dim(map, isl_dim_in);
1258 dom = isl_calloc_array(map->ctx, isl_set *, map->n);
1259 ran = isl_calloc_array(map->ctx, isl_set *, map->n);
1260 left = isl_calloc_array(map->ctx, int, map->n);
1261 right = isl_calloc_array(map->ctx, int, map->n);
1262 if (!ran || !dom || !left || !right)
1265 if (incemental_on_entire_domain(dim, map, dom, ran, left, right, &res) < 0)
1268 for (i = 0; !res && i < map->n; ++i) {
1270 int exact_i, spurious, comp;
1272 dom[i] = isl_set_from_basic_set(
1273 isl_basic_map_domain(
1274 isl_basic_map_copy(map->p[i])));
1278 ran[i] = isl_set_from_basic_set(
1279 isl_basic_map_range(
1280 isl_basic_map_copy(map->p[i])));
1283 C = isl_set_union(isl_set_copy(dom[i]),
1284 isl_set_copy(ran[i]));
1285 C = isl_set_from_basic_set(isl_set_simple_hull(C));
1292 comp = composability(C, i, dom, ran, left, right, map);
1293 if (!comp || comp < 0) {
1299 qc = q_closure(isl_dim_copy(dim), C, map->p[i], &exact_i);
1306 spurious = has_spurious_elements(qc, dom[i], ran[i]);
1313 qc = isl_map_project_out(qc, isl_dim_in, d, 1);
1314 qc = isl_map_project_out(qc, isl_dim_out, d, 1);
1315 qc = isl_map_compute_divs(qc);
1316 qc = compose(map, i, qc, (comp & LEFT) ? left : NULL,
1317 (comp & RIGHT) ? right : NULL);
1320 if (qc->n >= map->n) {
1324 res = compute_incremental(isl_dim_copy(dim), map, i, qc,
1325 (comp & LEFT) ? left : NULL,
1326 (comp & RIGHT) ? right : NULL, &exact_i);
1335 for (i = 0; i < map->n; ++i) {
1336 isl_set_free(dom[i]);
1337 isl_set_free(ran[i]);
1349 return construct_projected_component(dim, map, exact, project);
1352 for (i = 0; i < map->n; ++i)
1353 isl_set_free(dom[i]);
1356 for (i = 0; i < map->n; ++i)
1357 isl_set_free(ran[i]);
1365 /* Given an array of sets "set", add "dom" at position "pos"
1366 * and search for elements at earlier positions that overlap with "dom".
1367 * If any can be found, then merge all of them, together with "dom", into
1368 * a single set and assign the union to the first in the array,
1369 * which becomes the new group leader for all groups involved in the merge.
1370 * During the search, we only consider group leaders, i.e., those with
1371 * group[i] = i, as the other sets have already been combined
1372 * with one of the group leaders.
1374 static int merge(isl_set **set, int *group, __isl_take isl_set *dom, int pos)
1379 set[pos] = isl_set_copy(dom);
1381 for (i = pos - 1; i >= 0; --i) {
1387 o = isl_set_overlaps(set[i], dom);
1393 set[i] = isl_set_union(set[i], set[group[pos]]);
1394 set[group[pos]] = NULL;
1397 group[group[pos]] = i;
1408 /* Replace each entry in the n by n grid of maps by the cross product
1409 * with the relation { [i] -> [i + 1] }.
1411 static int add_length(__isl_keep isl_map *map, isl_map ***grid, int n)
1415 isl_basic_map *bstep;
1422 dim = isl_map_get_dim(map);
1423 nparam = isl_dim_size(dim, isl_dim_param);
1424 dim = isl_dim_drop(dim, isl_dim_in, 0, isl_dim_size(dim, isl_dim_in));
1425 dim = isl_dim_drop(dim, isl_dim_out, 0, isl_dim_size(dim, isl_dim_out));
1426 dim = isl_dim_add(dim, isl_dim_in, 1);
1427 dim = isl_dim_add(dim, isl_dim_out, 1);
1428 bstep = isl_basic_map_alloc_dim(dim, 0, 1, 0);
1429 k = isl_basic_map_alloc_equality(bstep);
1431 isl_basic_map_free(bstep);
1434 isl_seq_clr(bstep->eq[k], 1 + isl_basic_map_total_dim(bstep));
1435 isl_int_set_si(bstep->eq[k][0], 1);
1436 isl_int_set_si(bstep->eq[k][1 + nparam], 1);
1437 isl_int_set_si(bstep->eq[k][1 + nparam + 1], -1);
1438 bstep = isl_basic_map_finalize(bstep);
1439 step = isl_map_from_basic_map(bstep);
1441 for (i = 0; i < n; ++i)
1442 for (j = 0; j < n; ++j)
1443 grid[i][j] = isl_map_product(grid[i][j],
1444 isl_map_copy(step));
1451 /* The core of the Floyd-Warshall algorithm.
1452 * Updates the given n x x matrix of relations in place.
1454 * The algorithm iterates over all vertices. In each step, the whole
1455 * matrix is updated to include all paths that go to the current vertex,
1456 * possibly stay there a while (including passing through earlier vertices)
1457 * and then come back. At the start of each iteration, the diagonal
1458 * element corresponding to the current vertex is replaced by its
1459 * transitive closure to account for all indirect paths that stay
1460 * in the current vertex.
1462 static void floyd_warshall_iterate(isl_map ***grid, int n, int *exact)
1466 for (r = 0; r < n; ++r) {
1468 grid[r][r] = isl_map_transitive_closure(grid[r][r],
1469 (exact && *exact) ? &r_exact : NULL);
1470 if (exact && *exact && !r_exact)
1473 for (p = 0; p < n; ++p)
1474 for (q = 0; q < n; ++q) {
1476 if (p == r && q == r)
1478 loop = isl_map_apply_range(
1479 isl_map_copy(grid[p][r]),
1480 isl_map_copy(grid[r][q]));
1481 grid[p][q] = isl_map_union(grid[p][q], loop);
1482 loop = isl_map_apply_range(
1483 isl_map_copy(grid[p][r]),
1484 isl_map_apply_range(
1485 isl_map_copy(grid[r][r]),
1486 isl_map_copy(grid[r][q])));
1487 grid[p][q] = isl_map_union(grid[p][q], loop);
1488 grid[p][q] = isl_map_coalesce(grid[p][q]);
1493 /* Given a partition of the domains and ranges of the basic maps in "map",
1494 * apply the Floyd-Warshall algorithm with the elements in the partition
1497 * In particular, there are "n" elements in the partition and "group" is
1498 * an array of length 2 * map->n with entries in [0,n-1].
1500 * We first construct a matrix of relations based on the partition information,
1501 * apply Floyd-Warshall on this matrix of relations and then take the
1502 * union of all entries in the matrix as the final result.
1504 * If we are actually computing the power instead of the transitive closure,
1505 * i.e., when "project" is not set, then the result should have the
1506 * path lengths encoded as the difference between an extra pair of
1507 * coordinates. We therefore apply the nested transitive closures
1508 * to relations that include these lengths. In particular, we replace
1509 * the input relation by the cross product with the unit length relation
1510 * { [i] -> [i + 1] }.
1512 static __isl_give isl_map *floyd_warshall_with_groups(__isl_take isl_dim *dim,
1513 __isl_keep isl_map *map, int *exact, int project, int *group, int n)
1516 isl_map ***grid = NULL;
1524 return incremental_closure(dim, map, exact, project);
1527 grid = isl_calloc_array(map->ctx, isl_map **, n);
1530 for (i = 0; i < n; ++i) {
1531 grid[i] = isl_calloc_array(map->ctx, isl_map *, n);
1534 for (j = 0; j < n; ++j)
1535 grid[i][j] = isl_map_empty(isl_map_get_dim(map));
1538 for (k = 0; k < map->n; ++k) {
1540 j = group[2 * k + 1];
1541 grid[i][j] = isl_map_union(grid[i][j],
1542 isl_map_from_basic_map(
1543 isl_basic_map_copy(map->p[k])));
1546 if (!project && add_length(map, grid, n) < 0)
1549 floyd_warshall_iterate(grid, n, exact);
1551 app = isl_map_empty(isl_map_get_dim(map));
1553 for (i = 0; i < n; ++i) {
1554 for (j = 0; j < n; ++j)
1555 app = isl_map_union(app, grid[i][j]);
1566 for (i = 0; i < n; ++i) {
1569 for (j = 0; j < n; ++j)
1570 isl_map_free(grid[i][j]);
1579 /* Partition the domains and ranges of the n basic relations in list
1580 * into disjoint cells.
1582 * To find the partition, we simply consider all of the domains
1583 * and ranges in turn and combine those that overlap.
1584 * "set" contains the partition elements and "group" indicates
1585 * to which partition element a given domain or range belongs.
1586 * The domain of basic map i corresponds to element 2 * i in these arrays,
1587 * while the domain corresponds to element 2 * i + 1.
1588 * During the construction group[k] is either equal to k,
1589 * in which case set[k] contains the union of all the domains and
1590 * ranges in the corresponding group, or is equal to some l < k,
1591 * with l another domain or range in the same group.
1593 static int *setup_groups(isl_ctx *ctx, __isl_keep isl_basic_map **list, int n,
1594 isl_set ***set, int *n_group)
1600 *set = isl_calloc_array(ctx, isl_set *, 2 * n);
1601 group = isl_alloc_array(ctx, int, 2 * n);
1603 if (!*set || !group)
1606 for (i = 0; i < n; ++i) {
1608 dom = isl_set_from_basic_set(isl_basic_map_domain(
1609 isl_basic_map_copy(list[i])));
1610 if (merge(*set, group, dom, 2 * i) < 0)
1612 dom = isl_set_from_basic_set(isl_basic_map_range(
1613 isl_basic_map_copy(list[i])));
1614 if (merge(*set, group, dom, 2 * i + 1) < 0)
1619 for (i = 0; i < 2 * n; ++i)
1620 if (group[i] == i) {
1622 (*set)[g] = (*set)[i];
1627 group[i] = group[group[i]];
1634 for (i = 0; i < 2 * n; ++i)
1635 isl_set_free((*set)[i]);
1643 /* Check if the domains and ranges of the basic maps in "map" can
1644 * be partitioned, and if so, apply Floyd-Warshall on the elements
1645 * of the partition. Note that we also apply this algorithm
1646 * if we want to compute the power, i.e., when "project" is not set.
1647 * However, the results are unlikely to be exact since the recursive
1648 * calls inside the Floyd-Warshall algorithm typically result in
1649 * non-linear path lengths quite quickly.
1651 static __isl_give isl_map *floyd_warshall(__isl_take isl_dim *dim,
1652 __isl_keep isl_map *map, int *exact, int project)
1655 isl_set **set = NULL;
1662 return incremental_closure(dim, map, exact, project);
1664 group = setup_groups(map->ctx, map->p, map->n, &set, &n);
1668 for (i = 0; i < 2 * map->n; ++i)
1669 isl_set_free(set[i]);
1673 return floyd_warshall_with_groups(dim, map, exact, project, group, n);
1679 /* Structure for representing the nodes in the graph being traversed
1680 * using Tarjan's algorithm.
1681 * index represents the order in which nodes are visited.
1682 * min_index is the index of the root of a (sub)component.
1683 * on_stack indicates whether the node is currently on the stack.
1685 struct basic_map_sort_node {
1690 /* Structure for representing the graph being traversed
1691 * using Tarjan's algorithm.
1692 * len is the number of nodes
1693 * node is an array of nodes
1694 * stack contains the nodes on the path from the root to the current node
1695 * sp is the stack pointer
1696 * index is the index of the last node visited
1697 * order contains the elements of the components separated by -1
1698 * op represents the current position in order
1700 * check_closed is set if we may have used the fact that
1701 * a pair of basic maps can be interchanged
1703 struct basic_map_sort {
1705 struct basic_map_sort_node *node;
1714 static void basic_map_sort_free(struct basic_map_sort *s)
1724 static struct basic_map_sort *basic_map_sort_alloc(struct isl_ctx *ctx, int len)
1726 struct basic_map_sort *s;
1729 s = isl_calloc_type(ctx, struct basic_map_sort);
1733 s->node = isl_alloc_array(ctx, struct basic_map_sort_node, len);
1736 for (i = 0; i < len; ++i)
1737 s->node[i].index = -1;
1738 s->stack = isl_alloc_array(ctx, int, len);
1741 s->order = isl_alloc_array(ctx, int, 2 * len);
1749 s->check_closed = 0;
1753 basic_map_sort_free(s);
1757 /* Check whether in the computation of the transitive closure
1758 * "bmap1" (R_1) should follow (or be part of the same component as)
1761 * That is check whether
1769 * If so, then there is no reason for R_1 to immediately follow R_2
1772 * *check_closed is set if the subset relation holds while
1773 * R_1 \circ R_2 is not empty.
1775 static int basic_map_follows(__isl_keep isl_basic_map *bmap1,
1776 __isl_keep isl_basic_map *bmap2, int *check_closed)
1778 struct isl_map *map12 = NULL;
1779 struct isl_map *map21 = NULL;
1782 if (!isl_dim_tuple_match(bmap1->dim, isl_dim_in, bmap2->dim, isl_dim_out))
1785 map21 = isl_map_from_basic_map(
1786 isl_basic_map_apply_range(
1787 isl_basic_map_copy(bmap2),
1788 isl_basic_map_copy(bmap1)));
1789 subset = isl_map_is_empty(map21);
1793 isl_map_free(map21);
1797 if (!isl_dim_tuple_match(bmap1->dim, isl_dim_in, bmap1->dim, isl_dim_out) ||
1798 !isl_dim_tuple_match(bmap2->dim, isl_dim_in, bmap2->dim, isl_dim_out)) {
1799 isl_map_free(map21);
1803 map12 = isl_map_from_basic_map(
1804 isl_basic_map_apply_range(
1805 isl_basic_map_copy(bmap1),
1806 isl_basic_map_copy(bmap2)));
1808 subset = isl_map_is_subset(map21, map12);
1810 isl_map_free(map12);
1811 isl_map_free(map21);
1816 return subset < 0 ? -1 : !subset;
1818 isl_map_free(map21);
1822 /* Perform Tarjan's algorithm for computing the strongly connected components
1823 * in the graph with the disjuncts of "map" as vertices and with an
1824 * edge between any pair of disjuncts such that the first has
1825 * to be applied after the second.
1827 static int power_components_tarjan(struct basic_map_sort *s,
1828 __isl_keep isl_basic_map **list, int i)
1832 s->node[i].index = s->index;
1833 s->node[i].min_index = s->index;
1834 s->node[i].on_stack = 1;
1836 s->stack[s->sp++] = i;
1838 for (j = s->len - 1; j >= 0; --j) {
1843 if (s->node[j].index >= 0 &&
1844 (!s->node[j].on_stack ||
1845 s->node[j].index > s->node[i].min_index))
1848 f = basic_map_follows(list[i], list[j], &s->check_closed);
1854 if (s->node[j].index < 0) {
1855 power_components_tarjan(s, list, j);
1856 if (s->node[j].min_index < s->node[i].min_index)
1857 s->node[i].min_index = s->node[j].min_index;
1858 } else if (s->node[j].index < s->node[i].min_index)
1859 s->node[i].min_index = s->node[j].index;
1862 if (s->node[i].index != s->node[i].min_index)
1866 j = s->stack[--s->sp];
1867 s->node[j].on_stack = 0;
1868 s->order[s->op++] = j;
1870 s->order[s->op++] = -1;
1875 /* Decompose the "len" basic relations in "list" into strongly connected
1878 static struct basic_map_sort *basic_map_sort_init(isl_ctx *ctx, int len,
1879 __isl_keep isl_basic_map **list)
1882 struct basic_map_sort *s = NULL;
1884 s = basic_map_sort_alloc(ctx, len);
1887 for (i = len - 1; i >= 0; --i) {
1888 if (s->node[i].index >= 0)
1890 if (power_components_tarjan(s, list, i) < 0)
1896 basic_map_sort_free(s);
1900 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D
1901 * and a dimension specification (Z^{n+1} -> Z^{n+1}),
1902 * construct a map that is an overapproximation of the map
1903 * that takes an element from the dom R \times Z to an
1904 * element from ran R \times Z, such that the first n coordinates of the
1905 * difference between them is a sum of differences between images
1906 * and pre-images in one of the R_i and such that the last coordinate
1907 * is equal to the number of steps taken.
1908 * If "project" is set, then these final coordinates are not included,
1909 * i.e., a relation of type Z^n -> Z^n is returned.
1912 * \Delta_i = { y - x | (x, y) in R_i }
1914 * then the constructed map is an overapproximation of
1916 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
1917 * d = (\sum_i k_i \delta_i, \sum_i k_i) and
1918 * x in dom R and x + d in ran R }
1922 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
1923 * d = (\sum_i k_i \delta_i) and
1924 * x in dom R and x + d in ran R }
1926 * if "project" is set.
1928 * We first split the map into strongly connected components, perform
1929 * the above on each component and then join the results in the correct
1930 * order, at each join also taking in the union of both arguments
1931 * to allow for paths that do not go through one of the two arguments.
1933 static __isl_give isl_map *construct_power_components(__isl_take isl_dim *dim,
1934 __isl_keep isl_map *map, int *exact, int project)
1937 struct isl_map *path = NULL;
1938 struct basic_map_sort *s = NULL;
1945 return floyd_warshall(dim, map, exact, project);
1947 s = basic_map_sort_init(map->ctx, map->n, map->p);
1952 if (s->check_closed && !exact)
1953 exact = &local_exact;
1959 path = isl_map_empty(isl_map_get_dim(map));
1961 path = isl_map_empty(isl_dim_copy(dim));
1962 path = anonymize(path);
1964 struct isl_map *comp;
1965 isl_map *path_comp, *path_comb;
1966 comp = isl_map_alloc_dim(isl_map_get_dim(map), n, 0);
1967 while (s->order[i] != -1) {
1968 comp = isl_map_add_basic_map(comp,
1969 isl_basic_map_copy(map->p[s->order[i]]));
1973 path_comp = floyd_warshall(isl_dim_copy(dim),
1974 comp, exact, project);
1975 path_comb = isl_map_apply_range(isl_map_copy(path),
1976 isl_map_copy(path_comp));
1977 path = isl_map_union(path, path_comp);
1978 path = isl_map_union(path, path_comb);
1984 if (c > 1 && s->check_closed && !*exact) {
1987 closed = isl_map_is_transitively_closed(path);
1991 basic_map_sort_free(s);
1993 return floyd_warshall(dim, map, orig_exact, project);
1997 basic_map_sort_free(s);
2002 basic_map_sort_free(s);
2008 /* Given a union of basic maps R = \cup_i R_i \subseteq D \times D,
2009 * construct a map that is an overapproximation of the map
2010 * that takes an element from the space D to another
2011 * element from the same space, such that the difference between
2012 * them is a strictly positive sum of differences between images
2013 * and pre-images in one of the R_i.
2014 * The number of differences in the sum is equated to parameter "param".
2017 * \Delta_i = { y - x | (x, y) in R_i }
2019 * then the constructed map is an overapproximation of
2021 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
2022 * d = \sum_i k_i \delta_i and k = \sum_i k_i > 0 }
2025 * { (x) -> (x + d) | \exists k_i >= 0, \delta_i \in \Delta_i :
2026 * d = \sum_i k_i \delta_i and \sum_i k_i > 0 }
2028 * if "project" is set.
2030 * If "project" is not set, then
2031 * we construct an extended mapping with an extra coordinate
2032 * that indicates the number of steps taken. In particular,
2033 * the difference in the last coordinate is equal to the number
2034 * of steps taken to move from a domain element to the corresponding
2037 static __isl_give isl_map *construct_power(__isl_keep isl_map *map,
2038 int *exact, int project)
2040 struct isl_map *app = NULL;
2041 struct isl_dim *dim = NULL;
2047 dim = isl_map_get_dim(map);
2049 d = isl_dim_size(dim, isl_dim_in);
2050 dim = isl_dim_add(dim, isl_dim_in, 1);
2051 dim = isl_dim_add(dim, isl_dim_out, 1);
2053 app = construct_power_components(isl_dim_copy(dim), map,
2061 /* Compute the positive powers of "map", or an overapproximation.
2062 * If the result is exact, then *exact is set to 1.
2064 * If project is set, then we are actually interested in the transitive
2065 * closure, so we can use a more relaxed exactness check.
2066 * The lengths of the paths are also projected out instead of being
2067 * encoded as the difference between an extra pair of final coordinates.
2069 static __isl_give isl_map *map_power(__isl_take isl_map *map,
2070 int *exact, int project)
2072 struct isl_map *app = NULL;
2080 isl_assert(map->ctx,
2081 isl_map_dim(map, isl_dim_in) == isl_map_dim(map, isl_dim_out),
2084 app = construct_power(map, exact, project);
2094 /* Compute the positive powers of "map", or an overapproximation.
2095 * The power is given by parameter "param". If the result is exact,
2096 * then *exact is set to 1.
2097 * map_power constructs an extended relation with the path lengths
2098 * encoded as the difference between the final coordinates.
2099 * In the final step, this difference is equated to the parameter "param"
2100 * and made positive. The extra coordinates are subsequently projected out.
2102 __isl_give isl_map *isl_map_power(__isl_take isl_map *map, unsigned param,
2105 isl_dim *target_dim;
2113 isl_assert(map->ctx, param < isl_map_dim(map, isl_dim_param),
2116 d = isl_map_dim(map, isl_dim_in);
2118 map = isl_map_compute_divs(map);
2119 map = isl_map_coalesce(map);
2121 if (isl_map_fast_is_empty(map))
2124 target_dim = isl_map_get_dim(map);
2125 map = map_power(map, exact, 0);
2127 dim = isl_map_get_dim(map);
2128 diff = equate_parameter_to_length(dim, param);
2129 map = isl_map_intersect(map, diff);
2130 map = isl_map_project_out(map, isl_dim_in, d, 1);
2131 map = isl_map_project_out(map, isl_dim_out, d, 1);
2133 map = isl_map_reset_dim(map, target_dim);
2141 /* Compute a relation that maps each element in the range of the input
2142 * relation to the lengths of all paths composed of edges in the input
2143 * relation that end up in the given range element.
2144 * The result may be an overapproximation, in which case *exact is set to 0.
2145 * The resulting relation is very similar to the power relation.
2146 * The difference are that the domain has been projected out, the
2147 * range has become the domain and the exponent is the range instead
2150 __isl_give isl_map *isl_map_reaching_path_lengths(__isl_take isl_map *map,
2161 d = isl_map_dim(map, isl_dim_in);
2162 param = isl_map_dim(map, isl_dim_param);
2164 map = isl_map_compute_divs(map);
2165 map = isl_map_coalesce(map);
2167 if (isl_map_fast_is_empty(map)) {
2170 map = isl_map_project_out(map, isl_dim_out, 0, d);
2171 map = isl_map_add(map, isl_dim_out, 1);
2175 map = map_power(map, exact, 0);
2177 map = isl_map_add(map, isl_dim_param, 1);
2178 dim = isl_map_get_dim(map);
2179 diff = equate_parameter_to_length(dim, param);
2180 map = isl_map_intersect(map, diff);
2181 map = isl_map_project_out(map, isl_dim_in, 0, d + 1);
2182 map = isl_map_project_out(map, isl_dim_out, d, 1);
2183 map = isl_map_reverse(map);
2184 map = isl_map_move_dims(map, isl_dim_out, 0, isl_dim_param, param, 1);
2189 /* Check whether equality i of bset is a pure stride constraint
2190 * on a single dimensions, i.e., of the form
2194 * with k a constant and e an existentially quantified variable.
2196 static int is_eq_stride(__isl_keep isl_basic_set *bset, int i)
2208 if (!isl_int_is_zero(bset->eq[i][0]))
2211 nparam = isl_basic_set_dim(bset, isl_dim_param);
2212 d = isl_basic_set_dim(bset, isl_dim_set);
2213 n_div = isl_basic_set_dim(bset, isl_dim_div);
2215 if (isl_seq_first_non_zero(bset->eq[i] + 1, nparam) != -1)
2217 pos1 = isl_seq_first_non_zero(bset->eq[i] + 1 + nparam, d);
2220 if (isl_seq_first_non_zero(bset->eq[i] + 1 + nparam + pos1 + 1,
2221 d - pos1 - 1) != -1)
2224 pos2 = isl_seq_first_non_zero(bset->eq[i] + 1 + nparam + d, n_div);
2227 if (isl_seq_first_non_zero(bset->eq[i] + 1 + nparam + d + pos2 + 1,
2228 n_div - pos2 - 1) != -1)
2230 if (!isl_int_is_one(bset->eq[i][1 + nparam + pos1]) &&
2231 !isl_int_is_negone(bset->eq[i][1 + nparam + pos1]))
2237 /* Given a map, compute the smallest superset of this map that is of the form
2239 * { i -> j : L <= j - i <= U and exists a_p: j_p - i_p = M_p a_p }
2241 * (where p ranges over the (non-parametric) dimensions),
2242 * compute the transitive closure of this map, i.e.,
2244 * { i -> j : exists k > 0:
2245 * k L <= j - i <= k U and exists a: j_p - i_p = M_p a_p }
2247 * and intersect domain and range of this transitive closure with
2248 * the given domain and range.
2250 * If with_id is set, then try to include as much of the identity mapping
2251 * as possible, by computing
2253 * { i -> j : exists k >= 0:
2254 * k L <= j - i <= k U and exists a: j_p - i_p = M_p a_p }
2256 * instead (i.e., allow k = 0).
2258 * In practice, we compute the difference set
2260 * delta = { j - i | i -> j in map },
2262 * look for stride constraint on the individual dimensions and compute
2263 * (constant) lower and upper bounds for each individual dimension,
2264 * adding a constraint for each bound not equal to infinity.
2266 static __isl_give isl_map *box_closure_on_domain(__isl_take isl_map *map,
2267 __isl_take isl_set *dom, __isl_take isl_set *ran, int with_id)
2276 isl_map *app = NULL;
2277 isl_basic_set *aff = NULL;
2278 isl_basic_map *bmap = NULL;
2279 isl_vec *obj = NULL;
2284 delta = isl_map_deltas(isl_map_copy(map));
2286 aff = isl_set_affine_hull(isl_set_copy(delta));
2289 dim = isl_map_get_dim(map);
2290 d = isl_dim_size(dim, isl_dim_in);
2291 nparam = isl_dim_size(dim, isl_dim_param);
2292 total = isl_dim_total(dim);
2293 bmap = isl_basic_map_alloc_dim(dim,
2294 aff->n_div + 1, aff->n_div, 2 * d + 1);
2295 for (i = 0; i < aff->n_div + 1; ++i) {
2296 k = isl_basic_map_alloc_div(bmap);
2299 isl_int_set_si(bmap->div[k][0], 0);
2301 for (i = 0; i < aff->n_eq; ++i) {
2302 if (!is_eq_stride(aff, i))
2304 k = isl_basic_map_alloc_equality(bmap);
2307 isl_seq_clr(bmap->eq[k], 1 + nparam);
2308 isl_seq_cpy(bmap->eq[k] + 1 + nparam + d,
2309 aff->eq[i] + 1 + nparam, d);
2310 isl_seq_neg(bmap->eq[k] + 1 + nparam,
2311 aff->eq[i] + 1 + nparam, d);
2312 isl_seq_cpy(bmap->eq[k] + 1 + nparam + 2 * d,
2313 aff->eq[i] + 1 + nparam + d, aff->n_div);
2314 isl_int_set_si(bmap->eq[k][1 + total + aff->n_div], 0);
2316 obj = isl_vec_alloc(map->ctx, 1 + nparam + d);
2319 isl_seq_clr(obj->el, 1 + nparam + d);
2320 for (i = 0; i < d; ++ i) {
2321 enum isl_lp_result res;
2323 isl_int_set_si(obj->el[1 + nparam + i], 1);
2325 res = isl_set_solve_lp(delta, 0, obj->el, map->ctx->one, &opt,
2327 if (res == isl_lp_error)
2329 if (res == isl_lp_ok) {
2330 k = isl_basic_map_alloc_inequality(bmap);
2333 isl_seq_clr(bmap->ineq[k],
2334 1 + nparam + 2 * d + bmap->n_div);
2335 isl_int_set_si(bmap->ineq[k][1 + nparam + i], -1);
2336 isl_int_set_si(bmap->ineq[k][1 + nparam + d + i], 1);
2337 isl_int_neg(bmap->ineq[k][1 + nparam + 2 * d + aff->n_div], opt);
2340 res = isl_set_solve_lp(delta, 1, obj->el, map->ctx->one, &opt,
2342 if (res == isl_lp_error)
2344 if (res == isl_lp_ok) {
2345 k = isl_basic_map_alloc_inequality(bmap);
2348 isl_seq_clr(bmap->ineq[k],
2349 1 + nparam + 2 * d + bmap->n_div);
2350 isl_int_set_si(bmap->ineq[k][1 + nparam + i], 1);
2351 isl_int_set_si(bmap->ineq[k][1 + nparam + d + i], -1);
2352 isl_int_set(bmap->ineq[k][1 + nparam + 2 * d + aff->n_div], opt);
2355 isl_int_set_si(obj->el[1 + nparam + i], 0);
2357 k = isl_basic_map_alloc_inequality(bmap);
2360 isl_seq_clr(bmap->ineq[k],
2361 1 + nparam + 2 * d + bmap->n_div);
2363 isl_int_set_si(bmap->ineq[k][0], -1);
2364 isl_int_set_si(bmap->ineq[k][1 + nparam + 2 * d + aff->n_div], 1);
2366 app = isl_map_from_domain_and_range(dom, ran);
2369 isl_basic_set_free(aff);
2371 bmap = isl_basic_map_finalize(bmap);
2372 isl_set_free(delta);
2375 map = isl_map_from_basic_map(bmap);
2376 map = isl_map_intersect(map, app);
2381 isl_basic_map_free(bmap);
2382 isl_basic_set_free(aff);
2386 isl_set_free(delta);
2391 /* Given a map, compute the smallest superset of this map that is of the form
2393 * { i -> j : L <= j - i <= U and exists a_p: j_p - i_p = M_p a_p }
2395 * (where p ranges over the (non-parametric) dimensions),
2396 * compute the transitive closure of this map, i.e.,
2398 * { i -> j : exists k > 0:
2399 * k L <= j - i <= k U and exists a: j_p - i_p = M_p a_p }
2401 * and intersect domain and range of this transitive closure with
2402 * domain and range of the original map.
2404 static __isl_give isl_map *box_closure(__isl_take isl_map *map)
2409 domain = isl_map_domain(isl_map_copy(map));
2410 domain = isl_set_coalesce(domain);
2411 range = isl_map_range(isl_map_copy(map));
2412 range = isl_set_coalesce(range);
2414 return box_closure_on_domain(map, domain, range, 0);
2417 /* Given a map, compute the smallest superset of this map that is of the form
2419 * { i -> j : L <= j - i <= U and exists a_p: j_p - i_p = M_p a_p }
2421 * (where p ranges over the (non-parametric) dimensions),
2422 * compute the transitive and partially reflexive closure of this map, i.e.,
2424 * { i -> j : exists k >= 0:
2425 * k L <= j - i <= k U and exists a: j_p - i_p = M_p a_p }
2427 * and intersect domain and range of this transitive closure with
2430 static __isl_give isl_map *box_closure_with_identity(__isl_take isl_map *map,
2431 __isl_take isl_set *dom)
2433 return box_closure_on_domain(map, dom, isl_set_copy(dom), 1);
2436 /* Check whether app is the transitive closure of map.
2437 * In particular, check that app is acyclic and, if so,
2440 * app \subset (map \cup (map \circ app))
2442 static int check_exactness_omega(__isl_keep isl_map *map,
2443 __isl_keep isl_map *app)
2447 int is_empty, is_exact;
2451 delta = isl_map_deltas(isl_map_copy(app));
2452 d = isl_set_dim(delta, isl_dim_set);
2453 for (i = 0; i < d; ++i)
2454 delta = isl_set_fix_si(delta, isl_dim_set, i, 0);
2455 is_empty = isl_set_is_empty(delta);
2456 isl_set_free(delta);
2462 test = isl_map_apply_range(isl_map_copy(app), isl_map_copy(map));
2463 test = isl_map_union(test, isl_map_copy(map));
2464 is_exact = isl_map_is_subset(app, test);
2470 /* Check if basic map M_i can be combined with all the other
2471 * basic maps such that
2475 * can be computed as
2477 * M_i \cup (\cup_{j \ne i} M_i^* \circ M_j \circ M_i^*)^+
2479 * In particular, check if we can compute a compact representation
2482 * M_i^* \circ M_j \circ M_i^*
2485 * Let M_i^? be an extension of M_i^+ that allows paths
2486 * of length zero, i.e., the result of box_closure(., 1).
2487 * The criterion, as proposed by Kelly et al., is that
2488 * id = M_i^? - M_i^+ can be represented as a basic map
2491 * id \circ M_j \circ id = M_j
2495 * If this function returns 1, then tc and qc are set to
2496 * M_i^+ and M_i^?, respectively.
2498 static int can_be_split_off(__isl_keep isl_map *map, int i,
2499 __isl_give isl_map **tc, __isl_give isl_map **qc)
2501 isl_map *map_i, *id = NULL;
2508 C = isl_set_union(isl_map_domain(isl_map_copy(map)),
2509 isl_map_range(isl_map_copy(map)));
2510 C = isl_set_from_basic_set(isl_set_simple_hull(C));
2514 map_i = isl_map_from_basic_map(isl_basic_map_copy(map->p[i]));
2515 *tc = box_closure(isl_map_copy(map_i));
2516 *qc = box_closure_with_identity(map_i, C);
2517 id = isl_map_subtract(isl_map_copy(*qc), isl_map_copy(*tc));
2521 if (id->n != 1 || (*qc)->n != 1)
2524 for (j = 0; j < map->n; ++j) {
2525 isl_map *map_j, *test;
2530 map_j = isl_map_from_basic_map(
2531 isl_basic_map_copy(map->p[j]));
2532 test = isl_map_apply_range(isl_map_copy(id),
2533 isl_map_copy(map_j));
2534 test = isl_map_apply_range(test, isl_map_copy(id));
2535 is_ok = isl_map_is_equal(test, map_j);
2536 isl_map_free(map_j);
2564 static __isl_give isl_map *box_closure_with_check(__isl_take isl_map *map,
2569 app = box_closure(isl_map_copy(map));
2571 *exact = check_exactness_omega(map, app);
2577 /* Compute an overapproximation of the transitive closure of "map"
2578 * using a variation of the algorithm from
2579 * "Transitive Closure of Infinite Graphs and its Applications"
2582 * We first check whether we can can split of any basic map M_i and
2589 * M_i \cup (\cup_{j \ne i} M_i^* \circ M_j \circ M_i^*)^+
2591 * using a recursive call on the remaining map.
2593 * If not, we simply call box_closure on the whole map.
2595 static __isl_give isl_map *transitive_closure_omega(__isl_take isl_map *map,
2605 return box_closure_with_check(map, exact);
2607 for (i = 0; i < map->n; ++i) {
2610 ok = can_be_split_off(map, i, &tc, &qc);
2616 app = isl_map_alloc_dim(isl_map_get_dim(map), map->n - 1, 0);
2618 for (j = 0; j < map->n; ++j) {
2621 app = isl_map_add_basic_map(app,
2622 isl_basic_map_copy(map->p[j]));
2625 app = isl_map_apply_range(isl_map_copy(qc), app);
2626 app = isl_map_apply_range(app, qc);
2628 app = isl_map_union(tc, transitive_closure_omega(app, NULL));
2629 exact_i = check_exactness_omega(map, app);
2641 return box_closure_with_check(map, exact);
2647 /* Compute the transitive closure of "map", or an overapproximation.
2648 * If the result is exact, then *exact is set to 1.
2649 * Simply use map_power to compute the powers of map, but tell
2650 * it to project out the lengths of the paths instead of equating
2651 * the length to a parameter.
2653 __isl_give isl_map *isl_map_transitive_closure(__isl_take isl_map *map,
2656 isl_dim *target_dim;
2662 if (map->ctx->opt->closure == ISL_CLOSURE_OMEGA)
2663 return transitive_closure_omega(map, exact);
2665 map = isl_map_compute_divs(map);
2666 map = isl_map_coalesce(map);
2667 closed = isl_map_is_transitively_closed(map);
2676 target_dim = isl_map_get_dim(map);
2677 map = map_power(map, exact, 1);
2678 map = isl_map_reset_dim(map, target_dim);
2686 static int inc_count(__isl_take isl_map *map, void *user)
2697 static int collect_basic_map(__isl_take isl_map *map, void *user)
2700 isl_basic_map ***next = user;
2702 for (i = 0; i < map->n; ++i) {
2703 **next = isl_basic_map_copy(map->p[i]);
2716 /* Perform Floyd-Warshall on the given list of basic relations.
2717 * The basic relations may live in different dimensions,
2718 * but basic relations that get assigned to the diagonal of the
2719 * grid have domains and ranges of the same dimension and so
2720 * the standard algorithm can be used because the nested transitive
2721 * closures are only applied to diagonal elements and because all
2722 * compositions are peformed on relations with compatible domains and ranges.
2724 static __isl_give isl_union_map *union_floyd_warshall_on_list(isl_ctx *ctx,
2725 __isl_keep isl_basic_map **list, int n, int *exact)
2730 isl_set **set = NULL;
2731 isl_map ***grid = NULL;
2734 group = setup_groups(ctx, list, n, &set, &n_group);
2738 grid = isl_calloc_array(ctx, isl_map **, n_group);
2741 for (i = 0; i < n_group; ++i) {
2742 grid[i] = isl_calloc_array(map->ctx, isl_map *, n_group);
2745 for (j = 0; j < n_group; ++j) {
2746 isl_dim *dim1, *dim2, *dim;
2747 dim1 = isl_dim_reverse(isl_set_get_dim(set[i]));
2748 dim2 = isl_set_get_dim(set[j]);
2749 dim = isl_dim_join(dim1, dim2);
2750 grid[i][j] = isl_map_empty(dim);
2754 for (k = 0; k < n; ++k) {
2756 j = group[2 * k + 1];
2757 grid[i][j] = isl_map_union(grid[i][j],
2758 isl_map_from_basic_map(
2759 isl_basic_map_copy(list[k])));
2762 floyd_warshall_iterate(grid, n_group, exact);
2764 app = isl_union_map_empty(isl_map_get_dim(grid[0][0]));
2766 for (i = 0; i < n_group; ++i) {
2767 for (j = 0; j < n_group; ++j)
2768 app = isl_union_map_add_map(app, grid[i][j]);
2773 for (i = 0; i < 2 * n; ++i)
2774 isl_set_free(set[i]);
2781 for (i = 0; i < n_group; ++i) {
2784 for (j = 0; j < n_group; ++j)
2785 isl_map_free(grid[i][j]);
2790 for (i = 0; i < 2 * n; ++i)
2791 isl_set_free(set[i]);
2798 /* Perform Floyd-Warshall on the given union relation.
2799 * The implementation is very similar to that for non-unions.
2800 * The main difference is that it is applied unconditionally.
2801 * We first extract a list of basic maps from the union map
2802 * and then perform the algorithm on this list.
2804 static __isl_give isl_union_map *union_floyd_warshall(
2805 __isl_take isl_union_map *umap, int *exact)
2809 isl_basic_map **list;
2810 isl_basic_map **next;
2814 if (isl_union_map_foreach_map(umap, inc_count, &n) < 0)
2817 ctx = isl_union_map_get_ctx(umap);
2818 list = isl_calloc_array(ctx, isl_basic_map *, n);
2823 if (isl_union_map_foreach_map(umap, collect_basic_map, &next) < 0)
2826 res = union_floyd_warshall_on_list(ctx, list, n, exact);
2829 for (i = 0; i < n; ++i)
2830 isl_basic_map_free(list[i]);
2834 isl_union_map_free(umap);
2838 for (i = 0; i < n; ++i)
2839 isl_basic_map_free(list[i]);
2842 isl_union_map_free(umap);
2846 /* Decompose the give union relation into strongly connected components.
2847 * The implementation is essentially the same as that of
2848 * construct_power_components with the major difference that all
2849 * operations are performed on union maps.
2851 static __isl_give isl_union_map *union_components(
2852 __isl_take isl_union_map *umap, int *exact)
2857 isl_basic_map **list;
2858 isl_basic_map **next;
2859 isl_union_map *path = NULL;
2860 struct basic_map_sort *s = NULL;
2865 if (isl_union_map_foreach_map(umap, inc_count, &n) < 0)
2869 return union_floyd_warshall(umap, exact);
2871 ctx = isl_union_map_get_ctx(umap);
2872 list = isl_calloc_array(ctx, isl_basic_map *, n);
2877 if (isl_union_map_foreach_map(umap, collect_basic_map, &next) < 0)
2880 s = basic_map_sort_init(ctx, n, list);
2887 path = isl_union_map_empty(isl_union_map_get_dim(umap));
2889 isl_union_map *comp;
2890 isl_union_map *path_comp, *path_comb;
2891 comp = isl_union_map_empty(isl_union_map_get_dim(umap));
2892 while (s->order[i] != -1) {
2893 comp = isl_union_map_add_map(comp,
2894 isl_map_from_basic_map(
2895 isl_basic_map_copy(list[s->order[i]])));
2899 path_comp = union_floyd_warshall(comp, exact);
2900 path_comb = isl_union_map_apply_range(isl_union_map_copy(path),
2901 isl_union_map_copy(path_comp));
2902 path = isl_union_map_union(path, path_comp);
2903 path = isl_union_map_union(path, path_comb);
2908 if (c > 1 && s->check_closed && !*exact) {
2911 closed = isl_union_map_is_transitively_closed(path);
2917 basic_map_sort_free(s);
2919 for (i = 0; i < n; ++i)
2920 isl_basic_map_free(list[i]);
2924 isl_union_map_free(path);
2925 return union_floyd_warshall(umap, exact);
2928 isl_union_map_free(umap);
2932 basic_map_sort_free(s);
2934 for (i = 0; i < n; ++i)
2935 isl_basic_map_free(list[i]);
2938 isl_union_map_free(umap);
2939 isl_union_map_free(path);
2943 /* Compute the transitive closure of "umap", or an overapproximation.
2944 * If the result is exact, then *exact is set to 1.
2946 __isl_give isl_union_map *isl_union_map_transitive_closure(
2947 __isl_take isl_union_map *umap, int *exact)
2957 umap = isl_union_map_compute_divs(umap);
2958 umap = isl_union_map_coalesce(umap);
2959 closed = isl_union_map_is_transitively_closed(umap);
2964 umap = union_components(umap, exact);
2967 isl_union_map_free(umap);