isl_constraint.c

   1 /*
   2  * Copyright 2008-2009 Katholieke Universiteit Leuven
   3  * Copyright 2010      INRIA Saclay
   4  *
   5  * Use of this software is governed by the MIT license
   6  *
   7  * Written by Sven Verdoolaege, K.U.Leuven, Departement
   8  * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
   9  * and INRIA Saclay - Ile-de-France, Parc Club Orsay Universite,
  10  * ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France
  11  */
  12
  13 #include <isl_map_private.h>
  14 #include <isl_constraint_private.h>
  15 #include <isl_space_private.h>
  16 #include <isl/seq.h>
  17 #include <isl_aff_private.h>
  18 #include <isl_local_space_private.h>
  19 #include <isl_val_private.h>
  20
  21 #undef BASE
  22 #define BASE constraint
  23
  24 #include <isl_list_templ.c>
  25
  26 isl_ctx *isl_constraint_get_ctx(__isl_keep isl_constraint *c)
  27 {
  28         return c ? isl_local_space_get_ctx(c->ls) : NULL;
  29 }
  30
  31 static unsigned n(struct isl_constraint *c, enum isl_dim_type type)
  32 {
  33         return isl_local_space_dim(c->ls, type);
  34 }
  35
  36 static unsigned offset(struct isl_constraint *c, enum isl_dim_type type)
  37 {
  38         return isl_local_space_offset(c->ls, type);
  39 }
  40
  41 static unsigned basic_map_offset(__isl_keep isl_basic_map *bmap,
  42                                                         enum isl_dim_type type)
  43 {
  44         return type == isl_dim_div ? 1 + isl_space_dim(bmap->dim, isl_dim_all)
  45                                    : 1 + isl_space_offset(bmap->dim, type);
  46 }
  47
  48 static unsigned basic_set_offset(struct isl_basic_set *bset,
  49                                                         enum isl_dim_type type)
  50 {
  51         isl_space *dim = bset->dim;
  52         switch (type) {
  53         case isl_dim_param:     return 1;
  54         case isl_dim_in:        return 1 + dim->nparam;
  55         case isl_dim_out:       return 1 + dim->nparam + dim->n_in;
  56         case isl_dim_div:       return 1 + dim->nparam + dim->n_in + dim->n_out;
  57         default:                return 0;
  58         }
  59 }
  60
  61 __isl_give isl_constraint *isl_constraint_alloc_vec(int eq,
  62         __isl_take isl_local_space *ls, __isl_take isl_vec *v)
  63 {
  64         isl_constraint *constraint;
  65
  66         if (!ls || !v)
  67                 goto error;
  68
  69         constraint = isl_alloc_type(isl_vec_get_ctx(v), isl_constraint);
  70         if (!constraint)
  71                 goto error;
  72
  73         constraint->ref = 1;
  74         constraint->eq = eq;
  75         constraint->ls = ls;
  76         constraint->v = v;
  77
  78         return constraint;
  79 error:
  80         isl_local_space_free(ls);
  81         isl_vec_free(v);
  82         return NULL;
  83 }
  84
  85 __isl_give isl_constraint *isl_constraint_alloc(int eq,
  86         __isl_take isl_local_space *ls)
  87 {
  88         isl_ctx *ctx;
  89         isl_vec *v;
  90
  91         if (!ls)
  92                 return NULL;
  93
  94         ctx = isl_local_space_get_ctx(ls);
  95         v = isl_vec_alloc(ctx, 1 + isl_local_space_dim(ls, isl_dim_all));
  96         v = isl_vec_clr(v);
  97         return isl_constraint_alloc_vec(eq, ls, v);
  98 }
  99
 100 struct isl_constraint *isl_basic_map_constraint(struct isl_basic_map *bmap,
 101         isl_int **line)
 102 {
 103         int eq;
 104         isl_ctx *ctx;
 105         isl_vec *v;
 106         isl_local_space *ls = NULL;
 107         isl_constraint *constraint;
 108
 109         if (!bmap || !line)
 110                 goto error;
 111
 112         eq = line >= bmap->eq;
 113
 114         ctx = isl_basic_map_get_ctx(bmap);
 115         ls = isl_basic_map_get_local_space(bmap);
 116         v = isl_vec_alloc(ctx, 1 + isl_local_space_dim(ls, isl_dim_all));
 117         if (!v)
 118                 goto error;
 119         isl_seq_cpy(v->el, line[0], v->size);
 120         constraint = isl_constraint_alloc_vec(eq, ls, v);
 121
 122         isl_basic_map_free(bmap);
 123         return constraint;
 124 error:
 125         isl_local_space_free(ls);
 126         isl_basic_map_free(bmap);
 127         return NULL;
 128 }
 129
 130 struct isl_constraint *isl_basic_set_constraint(struct isl_basic_set *bset,
 131         isl_int **line)
 132 {
 133         return isl_basic_map_constraint((struct isl_basic_map *)bset, line);
 134 }
 135
 136 __isl_give isl_constraint *isl_equality_alloc(__isl_take isl_local_space *ls)
 137 {
 138         return isl_constraint_alloc(1, ls);
 139 }
 140
 141 __isl_give isl_constraint *isl_inequality_alloc(__isl_take isl_local_space *ls)
 142 {
 143         return isl_constraint_alloc(0, ls);
 144 }
 145
 146 struct isl_constraint *isl_constraint_dup(struct isl_constraint *c)
 147 {
 148         if (!c)
 149                 return NULL;
 150
 151         return isl_constraint_alloc_vec(c->eq, isl_local_space_copy(c->ls),
 152                                                 isl_vec_copy(c->v));
 153 }
 154
 155 struct isl_constraint *isl_constraint_cow(struct isl_constraint *c)
 156 {
 157         if (!c)
 158                 return NULL;
 159
 160         if (c->ref == 1)
 161                 return c;
 162         c->ref--;
 163         return isl_constraint_dup(c);
 164 }
 165
 166 struct isl_constraint *isl_constraint_copy(struct isl_constraint *constraint)
 167 {
 168         if (!constraint)
 169                 return NULL;
 170
 171         constraint->ref++;
 172         return constraint;
 173 }
 174
 175 void *isl_constraint_free(struct isl_constraint *c)
 176 {
 177         if (!c)
 178                 return NULL;
 179
 180         if (--c->ref > 0)
 181                 return NULL;
 182
 183         isl_local_space_free(c->ls);
 184         isl_vec_free(c->v);
 185         free(c);
 186
 187         return NULL;
 188 }
 189
 190 /* Return the number of constraints in "bset", i.e., the
 191  * number of times isl_basic_set_foreach_constraint will
 192  * call the callback.
 193  */
 194 int isl_basic_set_n_constraint(__isl_keep isl_basic_set *bset)
 195 {
 196         if (!bset)
 197                 return -1;
 198
 199         return bset->n_eq + bset->n_ineq;
 200 }
 201
 202 int isl_basic_map_foreach_constraint(__isl_keep isl_basic_map *bmap,
 203         int (*fn)(__isl_take isl_constraint *c, void *user), void *user)
 204 {
 205         int i;
 206         struct isl_constraint *c;
 207
 208         if (!bmap)
 209                 return -1;
 210
 211         isl_assert(bmap->ctx, ISL_F_ISSET(bmap, ISL_BASIC_MAP_FINAL),
 212                         return -1);
 213
 214         for (i = 0; i < bmap->n_eq; ++i) {
 215                 c = isl_basic_map_constraint(isl_basic_map_copy(bmap),
 216                                                 &bmap->eq[i]);
 217                 if (!c)
 218                         return -1;
 219                 if (fn(c, user) < 0)
 220                         return -1;
 221         }
 222
 223         for (i = 0; i < bmap->n_ineq; ++i) {
 224                 c = isl_basic_map_constraint(isl_basic_map_copy(bmap),
 225                                                 &bmap->ineq[i]);
 226                 if (!c)
 227                         return -1;
 228                 if (fn(c, user) < 0)
 229                         return -1;
 230         }
 231
 232         return 0;
 233 }
 234
 235 int isl_basic_set_foreach_constraint(__isl_keep isl_basic_set *bset,
 236         int (*fn)(__isl_take isl_constraint *c, void *user), void *user)
 237 {
 238         return isl_basic_map_foreach_constraint((isl_basic_map *)bset, fn, user);
 239 }
 240
 241 int isl_constraint_is_equal(struct isl_constraint *constraint1,
 242         struct isl_constraint *constraint2)
 243 {
 244         int equal;
 245
 246         if (!constraint1 || !constraint2)
 247                 return 0;
 248         if (constraint1->eq != constraint2->eq)
 249                 return 0;
 250         equal = isl_local_space_is_equal(constraint1->ls, constraint2->ls);
 251         if (equal < 0 || !equal)
 252                 return equal;
 253         return isl_vec_is_equal(constraint1->v, constraint2->v);
 254 }
 255
 256 struct isl_basic_map *isl_basic_map_add_constraint(
 257         struct isl_basic_map *bmap, struct isl_constraint *constraint)
 258 {
 259         isl_ctx *ctx;
 260         isl_space *dim;
 261         int equal_space;
 262
 263         if (!bmap || !constraint)
 264                 goto error;
 265
 266         ctx = isl_constraint_get_ctx(constraint);
 267         dim = isl_constraint_get_space(constraint);
 268         equal_space = isl_space_is_equal(bmap->dim, dim);
 269         isl_space_free(dim);
 270         isl_assert(ctx, equal_space, goto error);
 271
 272         bmap = isl_basic_map_intersect(bmap,
 273                                 isl_basic_map_from_constraint(constraint));
 274         return bmap;
 275 error:
 276         isl_basic_map_free(bmap);
 277         isl_constraint_free(constraint);
 278         return NULL;
 279 }
 280
 281 struct isl_basic_set *isl_basic_set_add_constraint(
 282         struct isl_basic_set *bset, struct isl_constraint *constraint)
 283 {
 284         return (struct isl_basic_set *)
 285                 isl_basic_map_add_constraint((struct isl_basic_map *)bset,
 286                                                 constraint);
 287 }
 288
 289 __isl_give isl_map *isl_map_add_constraint(__isl_take isl_map *map,
 290         __isl_take isl_constraint *constraint)
 291 {
 292         isl_basic_map *bmap;
 293
 294         bmap = isl_basic_map_from_constraint(constraint);
 295         map = isl_map_intersect(map, isl_map_from_basic_map(bmap));
 296
 297         return map;
 298 }
 299
 300 __isl_give isl_set *isl_set_add_constraint(__isl_take isl_set *set,
 301         __isl_take isl_constraint *constraint)
 302 {
 303         return isl_map_add_constraint(set, constraint);
 304 }
 305
 306 __isl_give isl_space *isl_constraint_get_space(
 307         __isl_keep isl_constraint *constraint)
 308 {
 309         return constraint ? isl_local_space_get_space(constraint->ls) : NULL;
 310 }
 311
 312 __isl_give isl_local_space *isl_constraint_get_local_space(
 313         __isl_keep isl_constraint *constraint)
 314 {
 315         return constraint ? isl_local_space_copy(constraint->ls) : NULL;
 316 }
 317
 318 int isl_constraint_dim(struct isl_constraint *constraint,
 319         enum isl_dim_type type)
 320 {
 321         if (!constraint)
 322                 return -1;
 323         return n(constraint, type);
 324 }
 325
 326 int isl_constraint_involves_dims(__isl_keep isl_constraint *constraint,
 327         enum isl_dim_type type, unsigned first, unsigned n)
 328 {
 329         int i;
 330         isl_ctx *ctx;
 331         int *active = NULL;
 332         int involves = 0;
 333
 334         if (!constraint)
 335                 return -1;
 336         if (n == 0)
 337                 return 0;
 338
 339         ctx = isl_constraint_get_ctx(constraint);
 340         if (first + n > isl_constraint_dim(constraint, type))
 341                 isl_die(ctx, isl_error_invalid,
 342                         "range out of bounds", return -1);
 343
 344         active = isl_local_space_get_active(constraint->ls,
 345                                             constraint->v->el + 1);
 346         if (!active)
 347                 goto error;
 348
 349         first += isl_local_space_offset(constraint->ls, type) - 1;
 350         for (i = 0; i < n; ++i)
 351                 if (active[first + i]) {
 352                         involves = 1;
 353                         break;
 354                 }
 355
 356         free(active);
 357
 358         return involves;
 359 error:
 360         free(active);
 361         return -1;
 362 }
 363
 364 /* Does the given constraint represent a lower bound on the given
 365  * dimension?
 366  */
 367 int isl_constraint_is_lower_bound(__isl_keep isl_constraint *constraint,
 368         enum isl_dim_type type, unsigned pos)
 369 {
 370         if (!constraint)
 371                 return -1;
 372
 373         if (pos >= isl_local_space_dim(constraint->ls, type))
 374                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 375                         "position out of bounds", return -1);
 376
 377         pos += isl_local_space_offset(constraint->ls, type);
 378         return isl_int_is_pos(constraint->v->el[pos]);
 379 }
 380
 381 /* Does the given constraint represent an upper bound on the given
 382  * dimension?
 383  */
 384 int isl_constraint_is_upper_bound(__isl_keep isl_constraint *constraint,
 385         enum isl_dim_type type, unsigned pos)
 386 {
 387         if (!constraint)
 388                 return -1;
 389
 390         if (pos >= isl_local_space_dim(constraint->ls, type))
 391                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 392                         "position out of bounds", return -1);
 393
 394         pos += isl_local_space_offset(constraint->ls, type);
 395         return isl_int_is_neg(constraint->v->el[pos]);
 396 }
 397
 398 const char *isl_constraint_get_dim_name(__isl_keep isl_constraint *constraint,
 399         enum isl_dim_type type, unsigned pos)
 400 {
 401         return constraint ?
 402             isl_local_space_get_dim_name(constraint->ls, type, pos) : NULL;
 403 }
 404
 405 void isl_constraint_get_constant(struct isl_constraint *constraint, isl_int *v)
 406 {
 407         if (!constraint)
 408                 return;
 409         isl_int_set(*v, constraint->v->el[0]);
 410 }
 411
 412 /* Return the constant term of "constraint".
 413  */
 414 __isl_give isl_val *isl_constraint_get_constant_val(
 415         __isl_keep isl_constraint *constraint)
 416 {
 417         isl_ctx *ctx;
 418
 419         if (!constraint)
 420                 return NULL;
 421
 422         ctx = isl_constraint_get_ctx(constraint);
 423         return isl_val_int_from_isl_int(ctx, constraint->v->el[0]);
 424 }
 425
 426 void isl_constraint_get_coefficient(struct isl_constraint *constraint,
 427         enum isl_dim_type type, int pos, isl_int *v)
 428 {
 429         if (!constraint)
 430                 return;
 431
 432         if (pos >= isl_local_space_dim(constraint->ls, type))
 433                 isl_die(constraint->v->ctx, isl_error_invalid,
 434                         "position out of bounds", return);
 435
 436         pos += isl_local_space_offset(constraint->ls, type);
 437         isl_int_set(*v, constraint->v->el[pos]);
 438 }
 439
 440 /* Return the coefficient of the variable of type "type" at position "pos"
 441  * of "constraint".
 442  */
 443 __isl_give isl_val *isl_constraint_get_coefficient_val(
 444         __isl_keep isl_constraint *constraint, enum isl_dim_type type, int pos)
 445 {
 446         isl_ctx *ctx;
 447
 448         if (!constraint)
 449                 return NULL;
 450
 451         ctx = isl_constraint_get_ctx(constraint);
 452         if (pos < 0 || pos >= isl_local_space_dim(constraint->ls, type))
 453                 isl_die(ctx, isl_error_invalid,
 454                         "position out of bounds", return NULL);
 455
 456         pos += isl_local_space_offset(constraint->ls, type);
 457         return isl_val_int_from_isl_int(ctx, constraint->v->el[pos]);
 458 }
 459
 460 __isl_give isl_aff *isl_constraint_get_div(__isl_keep isl_constraint *constraint,
 461         int pos)
 462 {
 463         if (!constraint)
 464                 return NULL;
 465
 466         return isl_local_space_get_div(constraint->ls, pos);
 467 }
 468
 469 __isl_give isl_constraint *isl_constraint_set_constant(
 470         __isl_take isl_constraint *constraint, isl_int v)
 471 {
 472         constraint = isl_constraint_cow(constraint);
 473         if (!constraint)
 474                 return NULL;
 475
 476         constraint->v = isl_vec_cow(constraint->v);
 477         if (!constraint->v)
 478                 return isl_constraint_free(constraint);
 479
 480         isl_int_set(constraint->v->el[0], v);
 481         return constraint;
 482 }
 483
 484 /* Replace the constant term of "constraint" by "v".
 485  */
 486 __isl_give isl_constraint *isl_constraint_set_constant_val(
 487         __isl_take isl_constraint *constraint, __isl_take isl_val *v)
 488 {
 489         constraint = isl_constraint_cow(constraint);
 490         if (!constraint || !v)
 491                 goto error;
 492         if (!isl_val_is_int(v))
 493                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 494                         "expecting integer value", goto error);
 495         constraint->v = isl_vec_set_element_val(constraint->v, 0, v);
 496         if (!constraint->v)
 497                 constraint = isl_constraint_free(constraint);
 498         return constraint;
 499 error:
 500         isl_val_free(v);
 501         return isl_constraint_free(constraint);
 502 }
 503
 504 __isl_give isl_constraint *isl_constraint_set_constant_si(
 505         __isl_take isl_constraint *constraint, int v)
 506 {
 507         constraint = isl_constraint_cow(constraint);
 508         if (!constraint)
 509                 return NULL;
 510
 511         constraint->v = isl_vec_cow(constraint->v);
 512         if (!constraint->v)
 513                 return isl_constraint_free(constraint);
 514
 515         isl_int_set_si(constraint->v->el[0], v);
 516         return constraint;
 517 }
 518
 519 __isl_give isl_constraint *isl_constraint_set_coefficient(
 520         __isl_take isl_constraint *constraint,
 521         enum isl_dim_type type, int pos, isl_int v)
 522 {
 523         constraint = isl_constraint_cow(constraint);
 524         if (!constraint)
 525                 return NULL;
 526
 527         if (pos >= isl_local_space_dim(constraint->ls, type))
 528                 isl_die(constraint->v->ctx, isl_error_invalid,
 529                         "position out of bounds",
 530                         return isl_constraint_free(constraint));
 531
 532         constraint = isl_constraint_cow(constraint);
 533         if (!constraint)
 534                 return NULL;
 535
 536         constraint->v = isl_vec_cow(constraint->v);
 537         if (!constraint->v)
 538                 return isl_constraint_free(constraint);
 539
 540         pos += isl_local_space_offset(constraint->ls, type);
 541         isl_int_set(constraint->v->el[pos], v);
 542
 543         return constraint;
 544 }
 545
 546 /* Replace the coefficient of the variable of type "type" at position "pos"
 547  * of "constraint" by "v".
 548  */
 549 __isl_give isl_constraint *isl_constraint_set_coefficient_val(
 550         __isl_take isl_constraint *constraint,
 551         enum isl_dim_type type, int pos, isl_val *v)
 552 {
 553         constraint = isl_constraint_cow(constraint);
 554         if (!constraint || !v)
 555                 goto error;
 556         if (!isl_val_is_int(v))
 557                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 558                         "expecting integer value", goto error);
 559
 560         if (pos >= isl_local_space_dim(constraint->ls, type))
 561                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 562                         "position out of bounds", goto error);
 563
 564         pos += isl_local_space_offset(constraint->ls, type);
 565         constraint->v = isl_vec_set_element_val(constraint->v, pos, v);
 566         if (!constraint->v)
 567                 constraint = isl_constraint_free(constraint);
 568         return constraint;
 569 error:
 570         isl_val_free(v);
 571         return isl_constraint_free(constraint);
 572 }
 573
 574 __isl_give isl_constraint *isl_constraint_set_coefficient_si(
 575         __isl_take isl_constraint *constraint,
 576         enum isl_dim_type type, int pos, int v)
 577 {
 578         constraint = isl_constraint_cow(constraint);
 579         if (!constraint)
 580                 return NULL;
 581
 582         if (pos >= isl_local_space_dim(constraint->ls, type))
 583                 isl_die(constraint->v->ctx, isl_error_invalid,
 584                         "position out of bounds",
 585                         return isl_constraint_free(constraint));
 586
 587         constraint = isl_constraint_cow(constraint);
 588         if (!constraint)
 589                 return NULL;
 590
 591         constraint->v = isl_vec_cow(constraint->v);
 592         if (!constraint->v)
 593                 return isl_constraint_free(constraint);
 594
 595         pos += isl_local_space_offset(constraint->ls, type);
 596         isl_int_set_si(constraint->v->el[pos], v);
 597
 598         return constraint;
 599 }
 600
 601 /* Drop any constraint from "bset" that is identical to "constraint".
 602  * In particular, this means that the local spaces of "bset" and
 603  * "constraint" need to be the same.
 604  *
 605  * Since the given constraint may actually be a pointer into the bset,
 606  * we have to be careful not to reorder the constraints as the user
 607  * may be holding on to other constraints from the same bset.
 608  * This should be cleaned up when the internal representation of
 609  * isl_constraint is changed to use isl_aff.
 610  */
 611 __isl_give isl_basic_set *isl_basic_set_drop_constraint(
 612         __isl_take isl_basic_set *bset, __isl_take isl_constraint *constraint)
 613 {
 614         int i;
 615         unsigned n;
 616         isl_int **row;
 617         unsigned total;
 618         isl_local_space *ls1;
 619         int equal;
 620
 621         if (!bset || !constraint)
 622                 goto error;
 623
 624         ls1 = isl_basic_set_get_local_space(bset);
 625         equal = isl_local_space_is_equal(ls1, constraint->ls);
 626         isl_local_space_free(ls1);
 627         if (equal < 0)
 628                 goto error;
 629         if (!equal) {
 630                 isl_constraint_free(constraint);
 631                 return bset;
 632         }
 633
 634         if (isl_constraint_is_equality(constraint)) {
 635                 n = bset->n_eq;
 636                 row = bset->eq;
 637         } else {
 638                 n = bset->n_ineq;
 639                 row = bset->ineq;
 640         }
 641
 642         total = isl_constraint_dim(constraint, isl_dim_all);
 643         for (i = 0; i < n; ++i)
 644                 if (isl_seq_eq(row[i], constraint->v->el, 1 + total))
 645                         isl_seq_clr(row[i], 1 + total);
 646
 647         isl_constraint_free(constraint);
 648         return bset;
 649 error:
 650         isl_constraint_free(constraint);
 651         isl_basic_set_free(bset);
 652         return NULL;
 653 }
 654
 655 struct isl_constraint *isl_constraint_negate(struct isl_constraint *constraint)
 656 {
 657         isl_ctx *ctx;
 658
 659         constraint = isl_constraint_cow(constraint);
 660         if (!constraint)
 661                 return NULL;
 662
 663         ctx = isl_constraint_get_ctx(constraint);
 664         if (isl_constraint_is_equality(constraint))
 665                 isl_die(ctx, isl_error_invalid, "cannot negate equality",
 666                         return isl_constraint_free(constraint));
 667         constraint->v = isl_vec_neg(constraint->v);
 668         constraint->v = isl_vec_cow(constraint->v);
 669         if (!constraint->v)
 670                 return isl_constraint_free(constraint);
 671         isl_int_sub_ui(constraint->v->el[0], constraint->v->el[0], 1);
 672         return constraint;
 673 }
 674
 675 int isl_constraint_is_equality(struct isl_constraint *constraint)
 676 {
 677         if (!constraint)
 678                 return -1;
 679         return constraint->eq;
 680 }
 681
 682 int isl_constraint_is_div_constraint(__isl_keep isl_constraint *constraint)
 683 {
 684         int i;
 685         int n_div;
 686
 687         if (!constraint)
 688                 return -1;
 689         if (isl_constraint_is_equality(constraint))
 690                 return 0;
 691         n_div = isl_constraint_dim(constraint, isl_dim_div);
 692         for (i = 0; i < n_div; ++i) {
 693                 if (isl_local_space_is_div_constraint(constraint->ls,
 694                                                         constraint->v->el, i))
 695                         return 1;
 696         }
 697
 698         return 0;
 699 }
 700
 701 /* We manually set ISL_BASIC_SET_FINAL instead of calling
 702  * isl_basic_map_finalize because we want to keep the position
 703  * of the divs and we therefore do not want to throw away redundant divs.
 704  * This is arguably a bit fragile.
 705  */
 706 __isl_give isl_basic_map *isl_basic_map_from_constraint(
 707         __isl_take isl_constraint *constraint)
 708 {
 709         int k;
 710         isl_local_space *ls;
 711         struct isl_basic_map *bmap;
 712         isl_int *c;
 713         unsigned total;
 714
 715         if (!constraint)
 716                 return NULL;
 717
 718         ls = isl_local_space_copy(constraint->ls);
 719         bmap = isl_basic_map_from_local_space(ls);
 720         bmap = isl_basic_map_extend_constraints(bmap, 1, 1);
 721         if (isl_constraint_is_equality(constraint)) {
 722                 k = isl_basic_map_alloc_equality(bmap);
 723                 if (k < 0)
 724                         goto error;
 725                 c = bmap->eq[k];
 726         }
 727         else {
 728                 k = isl_basic_map_alloc_inequality(bmap);
 729                 if (k < 0)
 730                         goto error;
 731                 c = bmap->ineq[k];
 732         }
 733         total = isl_basic_map_total_dim(bmap);
 734         isl_seq_cpy(c, constraint->v->el, 1 + total);
 735         isl_constraint_free(constraint);
 736         if (bmap)
 737                 ISL_F_SET(bmap, ISL_BASIC_SET_FINAL);
 738         return bmap;
 739 error:
 740         isl_constraint_free(constraint);
 741         isl_basic_map_free(bmap);
 742         return NULL;
 743 }
 744
 745 struct isl_basic_set *isl_basic_set_from_constraint(
 746         struct isl_constraint *constraint)
 747 {
 748         if (!constraint)
 749                 return NULL;
 750
 751         if (isl_constraint_dim(constraint, isl_dim_in) != 0)
 752                 isl_die(isl_constraint_get_ctx(constraint), isl_error_invalid,
 753                         "not a set constraint",
 754                         return isl_constraint_free(constraint));
 755         return (isl_basic_set *)isl_basic_map_from_constraint(constraint);
 756 }
 757
 758 int isl_basic_map_has_defining_equality(
 759         __isl_keep isl_basic_map *bmap, enum isl_dim_type type, int pos,
 760         __isl_give isl_constraint **c)
 761 {
 762         int i;
 763         unsigned offset;
 764         unsigned total;
 765
 766         if (!bmap)
 767                 return -1;
 768         offset = basic_map_offset(bmap, type);
 769         total = isl_basic_map_total_dim(bmap);
 770         isl_assert(bmap->ctx, pos < isl_basic_map_dim(bmap, type), return -1);
 771         for (i = 0; i < bmap->n_eq; ++i)
 772                 if (!isl_int_is_zero(bmap->eq[i][offset + pos]) &&
 773                     isl_seq_first_non_zero(bmap->eq[i]+offset+pos+1,
 774                                            1+total-offset-pos-1) == -1) {
 775                         *c = isl_basic_map_constraint(isl_basic_map_copy(bmap),
 776                                                                 &bmap->eq[i]);
 777                         return 1;
 778                 }
 779         return 0;
 780 }
 781
 782 int isl_basic_set_has_defining_equality(
 783         __isl_keep isl_basic_set *bset, enum isl_dim_type type, int pos,
 784         __isl_give isl_constraint **c)
 785 {
 786         return isl_basic_map_has_defining_equality((isl_basic_map *)bset,
 787                                                     type, pos, c);
 788 }
 789
 790 int isl_basic_set_has_defining_inequalities(
 791         struct isl_basic_set *bset, enum isl_dim_type type, int pos,
 792         struct isl_constraint **lower,
 793         struct isl_constraint **upper)
 794 {
 795         int i, j;
 796         unsigned offset;
 797         unsigned total;
 798         isl_int m;
 799         isl_int **lower_line, **upper_line;
 800
 801         if (!bset)
 802                 return -1;
 803         offset = basic_set_offset(bset, type);
 804         total = isl_basic_set_total_dim(bset);
 805         isl_assert(bset->ctx, pos < isl_basic_set_dim(bset, type), return -1);
 806         isl_int_init(m);
 807         for (i = 0; i < bset->n_ineq; ++i) {
 808                 if (isl_int_is_zero(bset->ineq[i][offset + pos]))
 809                         continue;
 810                 if (isl_int_is_one(bset->ineq[i][offset + pos]))
 811                         continue;
 812                 if (isl_int_is_negone(bset->ineq[i][offset + pos]))
 813                         continue;
 814                 if (isl_seq_first_non_zero(bset->ineq[i]+offset+pos+1,
 815                                                 1+total-offset-pos-1) != -1)
 816                         continue;
 817                 for (j = i + 1; j < bset->n_ineq; ++j) {
 818                         if (!isl_seq_is_neg(bset->ineq[i]+1, bset->ineq[j]+1,
 819                                             total))
 820                                 continue;
 821                         isl_int_add(m, bset->ineq[i][0], bset->ineq[j][0]);
 822                         if (isl_int_abs_ge(m, bset->ineq[i][offset+pos]))
 823                                 continue;
 824
 825                         if (isl_int_is_pos(bset->ineq[i][offset+pos])) {
 826                                 lower_line = &bset->ineq[i];
 827                                 upper_line = &bset->ineq[j];
 828                         } else {
 829                                 lower_line = &bset->ineq[j];
 830                                 upper_line = &bset->ineq[i];
 831                         }
 832                         *lower = isl_basic_set_constraint(
 833                                         isl_basic_set_copy(bset), lower_line);
 834                         *upper = isl_basic_set_constraint(
 835                                         isl_basic_set_copy(bset), upper_line);
 836                         isl_int_clear(m);
 837                         return 1;
 838                 }
 839         }
 840         *lower = NULL;
 841         *upper = NULL;
 842         isl_int_clear(m);
 843         return 0;
 844 }
 845
 846 /* Given two constraints "a" and "b" on the variable at position "abs_pos"
 847  * (in "a" and "b"), add a constraint to "bset" that ensures that the
 848  * bound implied by "a" is (strictly) larger than the bound implied by "b".
 849  *
 850  * If both constraints imply lower bounds, then this means that "a" is
 851  * active in the result.
 852  * If both constraints imply upper bounds, then this means that "b" is
 853  * active in the result.
 854  */
 855 static __isl_give isl_basic_set *add_larger_bound_constraint(
 856         __isl_take isl_basic_set *bset, isl_int *a, isl_int *b,
 857         unsigned abs_pos, int strict)
 858 {
 859         int k;
 860         isl_int t;
 861         unsigned total;
 862
 863         k = isl_basic_set_alloc_inequality(bset);
 864         if (k < 0)
 865                 goto error;
 866
 867         total = isl_basic_set_dim(bset, isl_dim_all);
 868
 869         isl_int_init(t);
 870         isl_int_neg(t, b[1 + abs_pos]);
 871
 872         isl_seq_combine(bset->ineq[k], t, a, a[1 + abs_pos], b, 1 + abs_pos);
 873         isl_seq_combine(bset->ineq[k] + 1 + abs_pos,
 874                 t, a + 1 + abs_pos + 1, a[1 + abs_pos], b + 1 + abs_pos + 1,
 875                 total - abs_pos);
 876
 877         if (strict)
 878                 isl_int_sub_ui(bset->ineq[k][0], bset->ineq[k][0], 1);
 879
 880         isl_int_clear(t);
 881
 882         return bset;
 883 error:
 884         isl_basic_set_free(bset);
 885         return NULL;
 886 }
 887
 888 /* Add constraints to "context" that ensure that "u" is the smallest
 889  * (and therefore active) upper bound on "abs_pos" in "bset" and return
 890  * the resulting basic set.
 891  */
 892 static __isl_give isl_basic_set *set_smallest_upper_bound(
 893         __isl_keep isl_basic_set *context,
 894         __isl_keep isl_basic_set *bset, unsigned abs_pos, int n_upper, int u)
 895 {
 896         int j;
 897
 898         context = isl_basic_set_copy(context);
 899         context = isl_basic_set_cow(context);
 900
 901         context = isl_basic_set_extend_constraints(context, 0, n_upper - 1);
 902
 903         for (j = 0; j < bset->n_ineq; ++j) {
 904                 if (j == u)
 905                         continue;
 906                 if (!isl_int_is_neg(bset->ineq[j][1 + abs_pos]))
 907                         continue;
 908                 context = add_larger_bound_constraint(context,
 909                         bset->ineq[j], bset->ineq[u], abs_pos, j > u);
 910         }
 911
 912         context = isl_basic_set_simplify(context);
 913         context = isl_basic_set_finalize(context);
 914
 915         return context;
 916 }
 917
 918 /* Add constraints to "context" that ensure that "u" is the largest
 919  * (and therefore active) upper bound on "abs_pos" in "bset" and return
 920  * the resulting basic set.
 921  */
 922 static __isl_give isl_basic_set *set_largest_lower_bound(
 923         __isl_keep isl_basic_set *context,
 924         __isl_keep isl_basic_set *bset, unsigned abs_pos, int n_lower, int l)
 925 {
 926         int j;
 927
 928         context = isl_basic_set_copy(context);
 929         context = isl_basic_set_cow(context);
 930
 931         context = isl_basic_set_extend_constraints(context, 0, n_lower - 1);
 932
 933         for (j = 0; j < bset->n_ineq; ++j) {
 934                 if (j == l)
 935                         continue;
 936                 if (!isl_int_is_pos(bset->ineq[j][1 + abs_pos]))
 937                         continue;
 938                 context = add_larger_bound_constraint(context,
 939                         bset->ineq[l], bset->ineq[j], abs_pos, j > l);
 940         }
 941
 942         context = isl_basic_set_simplify(context);
 943         context = isl_basic_set_finalize(context);
 944
 945         return context;
 946 }
 947
 948 static int foreach_upper_bound(__isl_keep isl_basic_set *bset,
 949         enum isl_dim_type type, unsigned abs_pos,
 950         __isl_take isl_basic_set *context, int n_upper,
 951         int (*fn)(__isl_take isl_constraint *lower,
 952                   __isl_take isl_constraint *upper,
 953                   __isl_take isl_basic_set *bset, void *user), void *user)
 954 {
 955         isl_basic_set *context_i;
 956         isl_constraint *upper = NULL;
 957         int i;
 958
 959         for (i = 0; i < bset->n_ineq; ++i) {
 960                 if (isl_int_is_zero(bset->ineq[i][1 + abs_pos]))
 961                         continue;
 962
 963                 context_i = set_smallest_upper_bound(context, bset,
 964                                                         abs_pos, n_upper, i);
 965                 if (isl_basic_set_is_empty(context_i)) {
 966                         isl_basic_set_free(context_i);
 967                         continue;
 968                 }
 969                 upper = isl_basic_set_constraint(isl_basic_set_copy(bset),
 970                                                 &bset->ineq[i]);
 971                 if (!upper || !context_i)
 972                         goto error;
 973                 if (fn(NULL, upper, context_i, user) < 0)
 974                         break;
 975         }
 976
 977         isl_basic_set_free(context);
 978
 979         if (i < bset->n_ineq)
 980                 return -1;
 981
 982         return 0;
 983 error:
 984         isl_constraint_free(upper);
 985         isl_basic_set_free(context_i);
 986         isl_basic_set_free(context);
 987         return -1;
 988 }
 989
 990 static int foreach_lower_bound(__isl_keep isl_basic_set *bset,
 991         enum isl_dim_type type, unsigned abs_pos,
 992         __isl_take isl_basic_set *context, int n_lower,
 993         int (*fn)(__isl_take isl_constraint *lower,
 994                   __isl_take isl_constraint *upper,
 995                   __isl_take isl_basic_set *bset, void *user), void *user)
 996 {
 997         isl_basic_set *context_i;
 998         isl_constraint *lower = NULL;
 999         int i;
1000
1001         for (i = 0; i < bset->n_ineq; ++i) {
1002                 if (isl_int_is_zero(bset->ineq[i][1 + abs_pos]))
1003                         continue;
1004
1005                 context_i = set_largest_lower_bound(context, bset,
1006                                                         abs_pos, n_lower, i);
1007                 if (isl_basic_set_is_empty(context_i)) {
1008                         isl_basic_set_free(context_i);
1009                         continue;
1010                 }
1011                 lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
1012                                                 &bset->ineq[i]);
1013                 if (!lower || !context_i)
1014                         goto error;
1015                 if (fn(lower, NULL, context_i, user) < 0)
1016                         break;
1017         }
1018
1019         isl_basic_set_free(context);
1020
1021         if (i < bset->n_ineq)
1022                 return -1;
1023
1024         return 0;
1025 error:
1026         isl_constraint_free(lower);
1027         isl_basic_set_free(context_i);
1028         isl_basic_set_free(context);
1029         return -1;
1030 }
1031
1032 static int foreach_bound_pair(__isl_keep isl_basic_set *bset,
1033         enum isl_dim_type type, unsigned abs_pos,
1034         __isl_take isl_basic_set *context, int n_lower, int n_upper,
1035         int (*fn)(__isl_take isl_constraint *lower,
1036                   __isl_take isl_constraint *upper,
1037                   __isl_take isl_basic_set *bset, void *user), void *user)
1038 {
1039         isl_basic_set *context_i, *context_j;
1040         isl_constraint *lower = NULL;
1041         isl_constraint *upper = NULL;
1042         int i, j;
1043
1044         for (i = 0; i < bset->n_ineq; ++i) {
1045                 if (!isl_int_is_pos(bset->ineq[i][1 + abs_pos]))
1046                         continue;
1047
1048                 context_i = set_largest_lower_bound(context, bset,
1049                                                         abs_pos, n_lower, i);
1050                 if (isl_basic_set_is_empty(context_i)) {
1051                         isl_basic_set_free(context_i);
1052                         continue;
1053                 }
1054
1055                 for (j = 0; j < bset->n_ineq; ++j) {
1056                         if (!isl_int_is_neg(bset->ineq[j][1 + abs_pos]))
1057                                 continue;
1058
1059                         context_j = set_smallest_upper_bound(context_i, bset,
1060                                                             abs_pos, n_upper, j);
1061                         context_j = isl_basic_set_extend_constraints(context_j,
1062                                                                         0, 1);
1063                         context_j = add_larger_bound_constraint(context_j,
1064                                 bset->ineq[i], bset->ineq[j], abs_pos, 0);
1065                         context_j = isl_basic_set_simplify(context_j);
1066                         context_j = isl_basic_set_finalize(context_j);
1067                         if (isl_basic_set_is_empty(context_j)) {
1068                                 isl_basic_set_free(context_j);
1069                                 continue;
1070                         }
1071                         lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
1072                                                         &bset->ineq[i]);
1073                         upper = isl_basic_set_constraint(isl_basic_set_copy(bset),
1074                                                         &bset->ineq[j]);
1075                         if (!lower || !upper || !context_j)
1076                                 goto error;
1077                         if (fn(lower, upper, context_j, user) < 0)
1078                                 break;
1079                 }
1080
1081                 isl_basic_set_free(context_i);
1082
1083                 if (j < bset->n_ineq)
1084                         break;
1085         }
1086
1087         isl_basic_set_free(context);
1088
1089         if (i < bset->n_ineq)
1090                 return -1;
1091
1092         return 0;
1093 error:
1094         isl_constraint_free(lower);
1095         isl_constraint_free(upper);
1096         isl_basic_set_free(context_i);
1097         isl_basic_set_free(context_j);
1098         isl_basic_set_free(context);
1099         return -1;
1100 }
1101
1102 /* For each pair of lower and upper bounds on the variable "pos"
1103  * of type "type", call "fn" with these lower and upper bounds and the
1104  * set of constraints on the remaining variables where these bounds
1105  * are active, i.e., (stricly) larger/smaller than the other lower/upper bounds.
1106  *
1107  * If the designated variable is equal to an affine combination of the
1108  * other variables then fn is called with both lower and upper
1109  * set to the corresponding equality.
1110  *
1111  * If there is no lower (or upper) bound, then NULL is passed
1112  * as the corresponding bound.
1113  *
1114  * We first check if the variable is involved in any equality.
1115  * If not, we count the number of lower and upper bounds and
1116  * act accordingly.
1117  */
1118 int isl_basic_set_foreach_bound_pair(__isl_keep isl_basic_set *bset,
1119         enum isl_dim_type type, unsigned pos,
1120         int (*fn)(__isl_take isl_constraint *lower,
1121                   __isl_take isl_constraint *upper,
1122                   __isl_take isl_basic_set *bset, void *user), void *user)
1123 {
1124         int i;
1125         isl_constraint *lower = NULL;
1126         isl_constraint *upper = NULL;
1127         isl_basic_set *context = NULL;
1128         unsigned abs_pos;
1129         int n_lower, n_upper;
1130
1131         if (!bset)
1132                 return -1;
1133         isl_assert(bset->ctx, pos < isl_basic_set_dim(bset, type), return -1);
1134         isl_assert(bset->ctx, type == isl_dim_param || type == isl_dim_set,
1135                 return -1);
1136
1137         abs_pos = pos;
1138         if (type == isl_dim_set)
1139                 abs_pos += isl_basic_set_dim(bset, isl_dim_param);
1140
1141         for (i = 0; i < bset->n_eq; ++i) {
1142                 if (isl_int_is_zero(bset->eq[i][1 + abs_pos]))
1143                         continue;
1144
1145                 lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
1146                                                 &bset->eq[i]);
1147                 upper = isl_constraint_copy(lower);
1148                 context = isl_basic_set_remove_dims(isl_basic_set_copy(bset),
1149                                         type, pos, 1);
1150                 if (!lower || !upper || !context)
1151                         goto error;
1152                 return fn(lower, upper, context, user);
1153         }
1154
1155         n_lower = 0;
1156         n_upper = 0;
1157         for (i = 0; i < bset->n_ineq; ++i) {
1158                 if (isl_int_is_pos(bset->ineq[i][1 + abs_pos]))
1159                         n_lower++;
1160                 else if (isl_int_is_neg(bset->ineq[i][1 + abs_pos]))
1161                         n_upper++;
1162         }
1163
1164         context = isl_basic_set_copy(bset);
1165         context = isl_basic_set_cow(context);
1166         if (!context)
1167                 goto error;
1168         for (i = context->n_ineq - 1; i >= 0; --i)
1169                 if (!isl_int_is_zero(context->ineq[i][1 + abs_pos]))
1170                         isl_basic_set_drop_inequality(context, i);
1171
1172         context = isl_basic_set_drop(context, type, pos, 1);
1173         if (!n_lower && !n_upper)
1174                 return fn(NULL, NULL, context, user);
1175         if (!n_lower)
1176                 return foreach_upper_bound(bset, type, abs_pos, context, n_upper,
1177                                                 fn, user);
1178         if (!n_upper)
1179                 return foreach_lower_bound(bset, type, abs_pos, context, n_lower,
1180                                                 fn, user);
1181         return foreach_bound_pair(bset, type, abs_pos, context, n_lower, n_upper,
1182                                         fn, user);
1183 error:
1184         isl_constraint_free(lower);
1185         isl_constraint_free(upper);
1186         isl_basic_set_free(context);
1187         return -1;
1188 }
1189
1190 __isl_give isl_aff *isl_constraint_get_bound(
1191         __isl_keep isl_constraint *constraint, enum isl_dim_type type, int pos)
1192 {
1193         isl_aff *aff;
1194         isl_ctx *ctx;
1195
1196         if (!constraint)
1197                 return NULL;
1198         ctx = isl_constraint_get_ctx(constraint);
1199         if (pos >= isl_constraint_dim(constraint, type))
1200                 isl_die(ctx, isl_error_invalid,
1201                         "index out of bounds", return NULL);
1202         if (isl_constraint_dim(constraint, isl_dim_in) != 0)
1203                 isl_die(ctx, isl_error_invalid,
1204                         "not a set constraint", return NULL);
1205
1206         pos += offset(constraint, type);
1207         if (isl_int_is_zero(constraint->v->el[pos]))
1208                 isl_die(ctx, isl_error_invalid,
1209                         "constraint does not define a bound on given dimension",
1210                         return NULL);
1211
1212         aff = isl_aff_alloc(isl_local_space_copy(constraint->ls));
1213         if (!aff)
1214                 return NULL;
1215
1216         if (isl_int_is_neg(constraint->v->el[pos]))
1217                 isl_seq_cpy(aff->v->el + 1, constraint->v->el, aff->v->size - 1);
1218         else
1219                 isl_seq_neg(aff->v->el + 1, constraint->v->el, aff->v->size - 1);
1220         isl_int_set_si(aff->v->el[1 + pos], 0);
1221         isl_int_abs(aff->v->el[0], constraint->v->el[pos]);
1222
1223         return aff;
1224 }
1225
1226 /* For an inequality constraint
1227  *
1228  *      f >= 0
1229  *
1230  * or an equality constraint
1231  *
1232  *      f = 0
1233  *
1234  * return the affine expression f.
1235  */
1236 __isl_give isl_aff *isl_constraint_get_aff(
1237         __isl_keep isl_constraint *constraint)
1238 {
1239         isl_aff *aff;
1240
1241         if (!constraint)
1242                 return NULL;
1243
1244         aff = isl_aff_alloc(isl_local_space_copy(constraint->ls));
1245         if (!aff)
1246                 return NULL;
1247
1248         isl_seq_cpy(aff->v->el + 1, constraint->v->el, aff->v->size - 1);
1249         isl_int_set_si(aff->v->el[0], 1);
1250
1251         return aff;
1252 }
1253
1254 /* Construct an equality constraint equating the given affine expression
1255  * to zero.
1256  */
1257 __isl_give isl_constraint *isl_equality_from_aff(__isl_take isl_aff *aff)
1258 {
1259         int k;
1260         isl_local_space *ls;
1261         isl_basic_set *bset;
1262
1263         if (!aff)
1264                 return NULL;
1265
1266         ls = isl_aff_get_domain_local_space(aff);
1267         bset = isl_basic_set_from_local_space(ls);
1268         bset = isl_basic_set_extend_constraints(bset, 1, 0);
1269         k = isl_basic_set_alloc_equality(bset);
1270         if (k < 0)
1271                 goto error;
1272
1273         isl_seq_cpy(bset->eq[k], aff->v->el + 1, aff->v->size - 1);
1274         isl_aff_free(aff);
1275
1276         return isl_basic_set_constraint(bset, &bset->eq[k]);
1277 error:
1278         isl_aff_free(aff);
1279         isl_basic_set_free(bset);
1280         return NULL;
1281 }
1282
1283 /* Construct an inequality constraint enforcing the given affine expression
1284  * to be non-negative.
1285  */
1286 __isl_give isl_constraint *isl_inequality_from_aff(__isl_take isl_aff *aff)
1287 {
1288         int k;
1289         isl_local_space *ls;
1290         isl_basic_set *bset;
1291
1292         if (!aff)
1293                 return NULL;
1294
1295         ls = isl_aff_get_domain_local_space(aff);
1296         bset = isl_basic_set_from_local_space(ls);
1297         bset = isl_basic_set_extend_constraints(bset, 0, 1);
1298         k = isl_basic_set_alloc_inequality(bset);
1299         if (k < 0)
1300                 goto error;
1301
1302         isl_seq_cpy(bset->ineq[k], aff->v->el + 1, aff->v->size - 1);
1303         isl_aff_free(aff);
1304
1305         return isl_basic_set_constraint(bset, &bset->ineq[k]);
1306 error:
1307         isl_aff_free(aff);
1308         isl_basic_set_free(bset);
1309         return NULL;
1310 }