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 GNU LGPLv2.1 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_constraint.h>
  14 #include <isl_dim_private.h>
  15 #include "isl_seq.h"
  16 #include "isl_map_private.h"
  17
  18 static unsigned n(struct isl_constraint *c, enum isl_dim_type type)
  19 {
  20         return isl_basic_map_dim(c->bmap, type);
  21 }
  22
  23 static unsigned offset(struct isl_constraint *c, enum isl_dim_type type)
  24 {
  25         struct isl_dim *dim = c->bmap->dim;
  26         switch (type) {
  27         case isl_dim_param:     return 1;
  28         case isl_dim_in:        return 1 + dim->nparam;
  29         case isl_dim_out:       return 1 + dim->nparam + dim->n_in;
  30         case isl_dim_div:       return 1 + dim->nparam + dim->n_in + dim->n_out;
  31         default:                return 0;
  32         }
  33 }
  34
  35 static unsigned basic_set_offset(struct isl_basic_set *bset,
  36                                                         enum isl_dim_type type)
  37 {
  38         struct isl_dim *dim = bset->dim;
  39         switch (type) {
  40         case isl_dim_param:     return 1;
  41         case isl_dim_in:        return 1 + dim->nparam;
  42         case isl_dim_out:       return 1 + dim->nparam + dim->n_in;
  43         case isl_dim_div:       return 1 + dim->nparam + dim->n_in + dim->n_out;
  44         default:                return 0;
  45         }
  46 }
  47
  48 struct isl_constraint *isl_basic_map_constraint(struct isl_basic_map *bmap,
  49         isl_int **line)
  50 {
  51         struct isl_constraint *constraint;
  52
  53         if (!bmap || !line)
  54                 goto error;
  55
  56         constraint = isl_alloc_type(bmap->ctx, struct isl_constraint);
  57         if (!constraint)
  58                 goto error;
  59
  60         constraint->ctx = bmap->ctx;
  61         isl_ctx_ref(constraint->ctx);
  62         constraint->ref = 1;
  63         constraint->bmap = bmap;
  64         constraint->line = line;
  65
  66         return constraint;
  67 error:
  68         isl_basic_map_free(bmap);
  69         return NULL;
  70 }
  71
  72 struct isl_constraint *isl_basic_set_constraint(struct isl_basic_set *bset,
  73         isl_int **line)
  74 {
  75         return isl_basic_map_constraint((struct isl_basic_map *)bset, line);
  76 }
  77
  78 struct isl_constraint *isl_equality_alloc(struct isl_dim *dim)
  79 {
  80         struct isl_basic_map *bmap;
  81
  82         if (!dim)
  83                 return NULL;
  84
  85         bmap = isl_basic_map_alloc_dim(dim, 0, 1, 0);
  86         if (!bmap)
  87                 return NULL;
  88
  89         isl_basic_map_alloc_equality(bmap);
  90         isl_seq_clr(bmap->eq[0], 1 + isl_basic_map_total_dim(bmap));
  91         return isl_basic_map_constraint(bmap, &bmap->eq[0]);
  92 }
  93
  94 struct isl_constraint *isl_inequality_alloc(struct isl_dim *dim)
  95 {
  96         struct isl_basic_map *bmap;
  97
  98         if (!dim)
  99                 return NULL;
 100
 101         bmap = isl_basic_map_alloc_dim(dim, 0, 0, 1);
 102         if (!bmap)
 103                 return NULL;
 104
 105         isl_basic_map_alloc_inequality(bmap);
 106         isl_seq_clr(bmap->ineq[0], 1 + isl_basic_map_total_dim(bmap));
 107         return isl_basic_map_constraint(bmap, &bmap->ineq[0]);
 108 }
 109
 110 struct isl_constraint *isl_constraint_dup(struct isl_constraint *c)
 111 {
 112         struct isl_basic_map *bmap;
 113         int i;
 114         int eq;
 115
 116         if (!c)
 117                 return NULL;
 118
 119         eq = c->line < c->bmap->eq + c->bmap->n_eq;
 120         i = eq ? c->line - c->bmap->eq : c->line - c->bmap->ineq;
 121         bmap = isl_basic_map_copy(c->bmap);
 122         if (!bmap)
 123                 return NULL;
 124         return isl_basic_map_constraint(bmap, eq ? bmap->eq + i : bmap->ineq + i);
 125 }
 126
 127 struct isl_constraint *isl_constraint_cow(struct isl_constraint *c)
 128 {
 129         if (!c)
 130                 return NULL;
 131
 132         if (c->ref == 1)
 133                 return c;
 134         c->ref--;
 135         return isl_constraint_dup(c);
 136 }
 137
 138 struct isl_constraint *isl_constraint_copy(struct isl_constraint *constraint)
 139 {
 140         if (!constraint)
 141                 return NULL;
 142
 143         constraint->ref++;
 144         return constraint;
 145 }
 146
 147 void isl_constraint_free(struct isl_constraint *c)
 148 {
 149         if (!c)
 150                 return;
 151
 152         if (--c->ref > 0)
 153                 return;
 154
 155         isl_basic_map_free(c->bmap);
 156         isl_ctx_deref(c->ctx);
 157         free(c);
 158 }
 159
 160 __isl_give isl_constraint *isl_basic_map_first_constraint(
 161         __isl_take isl_basic_map *bmap)
 162 {
 163         if (!bmap)
 164                 return NULL;
 165
 166         if (bmap->n_eq > 0)
 167                 return isl_basic_map_constraint(bmap, &bmap->eq[0]);
 168
 169         if (bmap->n_ineq > 0)
 170                 return isl_basic_map_constraint(bmap, &bmap->ineq[0]);
 171
 172         isl_basic_map_free(bmap);
 173         return NULL;
 174 }
 175
 176 __isl_give isl_constraint *isl_basic_set_first_constraint(
 177         __isl_take isl_basic_set *bset)
 178 {
 179         return isl_basic_map_first_constraint((struct isl_basic_map *)bset);
 180 }
 181
 182 struct isl_constraint *isl_constraint_next(struct isl_constraint *c)
 183 {
 184         c = isl_constraint_cow(c);
 185         if (c->line >= c->bmap->eq) {
 186                 c->line++;
 187                 if (c->line < c->bmap->eq + c->bmap->n_eq)
 188                         return c;
 189                 c->line = c->bmap->ineq;
 190         } else
 191                 c->line++;
 192         if (c->line < c->bmap->ineq + c->bmap->n_ineq)
 193                 return c;
 194         isl_constraint_free(c);
 195         return NULL;
 196 }
 197
 198 int isl_basic_map_foreach_constraint(__isl_keep isl_basic_map *bmap,
 199         int (*fn)(__isl_take isl_constraint *c, void *user), void *user)
 200 {
 201         int i;
 202         struct isl_constraint *c;
 203
 204         if (!bmap)
 205                 return -1;
 206
 207         isl_assert(bmap->ctx, ISL_F_ISSET(bmap, ISL_BASIC_MAP_FINAL),
 208                         return -1);
 209
 210         for (i = 0; i < bmap->n_eq; ++i) {
 211                 c = isl_basic_map_constraint(isl_basic_map_copy(bmap),
 212                                                 &bmap->eq[i]);
 213                 if (!c)
 214                         return -1;
 215                 if (fn(c, user) < 0)
 216                         return -1;
 217         }
 218
 219         for (i = 0; i < bmap->n_ineq; ++i) {
 220                 c = isl_basic_map_constraint(isl_basic_map_copy(bmap),
 221                                                 &bmap->ineq[i]);
 222                 if (!c)
 223                         return -1;
 224                 if (fn(c, user) < 0)
 225                         return -1;
 226         }
 227
 228         return 0;
 229 }
 230
 231 int isl_basic_set_foreach_constraint(__isl_keep isl_basic_set *bset,
 232         int (*fn)(__isl_take isl_constraint *c, void *user), void *user)
 233 {
 234         return isl_basic_map_foreach_constraint((isl_basic_map *)bset, fn, user);
 235 }
 236
 237 int isl_constraint_is_equal(struct isl_constraint *constraint1,
 238         struct isl_constraint *constraint2)
 239 {
 240         if (!constraint1 || !constraint2)
 241                 return 0;
 242         return constraint1->bmap == constraint2->bmap &&
 243                constraint1->line == constraint2->line;
 244 }
 245
 246 struct isl_basic_map *isl_basic_map_add_constraint(
 247         struct isl_basic_map *bmap, struct isl_constraint *constraint)
 248 {
 249         if (!bmap || !constraint)
 250                 goto error;
 251
 252         isl_assert(constraint->ctx,
 253                 isl_dim_equal(bmap->dim, constraint->bmap->dim), goto error);
 254
 255         bmap = isl_basic_map_intersect(bmap,
 256                                 isl_basic_map_from_constraint(constraint));
 257         return bmap;
 258 error:
 259         isl_basic_map_free(bmap);
 260         isl_constraint_free(constraint);
 261         return NULL;
 262 }
 263
 264 struct isl_basic_set *isl_basic_set_add_constraint(
 265         struct isl_basic_set *bset, struct isl_constraint *constraint)
 266 {
 267         return (struct isl_basic_set *)
 268                 isl_basic_map_add_constraint((struct isl_basic_map *)bset,
 269                                                 constraint);
 270 }
 271
 272 struct isl_constraint *isl_constraint_add_div(struct isl_constraint *constraint,
 273         struct isl_div *div, int *pos)
 274 {
 275         if (!constraint || !div)
 276                 goto error;
 277
 278         isl_assert(constraint->ctx,
 279             isl_dim_equal(div->bmap->dim, constraint->bmap->dim), goto error);
 280         isl_assert(constraint->ctx,
 281             constraint->bmap->n_eq + constraint->bmap->n_ineq == 1, goto error);
 282
 283         constraint->bmap = isl_basic_map_cow(constraint->bmap);
 284         constraint->bmap = isl_basic_map_extend_dim(constraint->bmap,
 285                                 isl_dim_copy(constraint->bmap->dim), 1, 0, 0);
 286         if (!constraint->bmap)
 287                 goto error;
 288         constraint->line = &constraint->bmap->ineq[0];
 289         *pos = isl_basic_map_alloc_div(constraint->bmap);
 290         if (*pos < 0)
 291                 goto error;
 292         isl_seq_cpy(constraint->bmap->div[*pos], div->line[0],
 293                         1 + 1 + isl_basic_map_total_dim(constraint->bmap));
 294         isl_div_free(div);
 295         return constraint;
 296 error:
 297         isl_constraint_free(constraint);
 298         isl_div_free(div);
 299         return NULL;
 300 }
 301
 302 int isl_constraint_dim(struct isl_constraint *constraint,
 303         enum isl_dim_type type)
 304 {
 305         if (!constraint)
 306                 return -1;
 307         return n(constraint, type);
 308 }
 309
 310 void isl_constraint_get_constant(struct isl_constraint *constraint, isl_int *v)
 311 {
 312         if (!constraint)
 313                 return;
 314         isl_int_set(*v, constraint->line[0][0]);
 315 }
 316
 317 void isl_constraint_get_coefficient(struct isl_constraint *constraint,
 318         enum isl_dim_type type, int pos, isl_int *v)
 319 {
 320         if (!constraint)
 321                 return;
 322
 323         isl_assert(constraint->ctx, pos < n(constraint, type), return);
 324         isl_int_set(*v, constraint->line[0][offset(constraint, type) + pos]);
 325 }
 326
 327 struct isl_div *isl_constraint_div(struct isl_constraint *constraint, int pos)
 328 {
 329         if (!constraint)
 330                 return NULL;
 331
 332         isl_assert(constraint->ctx, pos < n(constraint, isl_dim_div),
 333                         return NULL);
 334         isl_assert(constraint->ctx,
 335                 !isl_int_is_zero(constraint->bmap->div[pos][0]), return NULL);
 336         return isl_basic_map_div(isl_basic_map_copy(constraint->bmap), pos);
 337 }
 338
 339 void isl_constraint_set_constant(struct isl_constraint *constraint, isl_int v)
 340 {
 341         if (!constraint)
 342                 return;
 343         isl_int_set(constraint->line[0][0], v);
 344 }
 345
 346 void isl_constraint_set_coefficient(struct isl_constraint *constraint,
 347         enum isl_dim_type type, int pos, isl_int v)
 348 {
 349         if (!constraint)
 350                 return;
 351
 352         isl_assert(constraint->ctx, pos < n(constraint, type), return);
 353         isl_int_set(constraint->line[0][offset(constraint, type) + pos], v);
 354 }
 355
 356 void isl_constraint_clear(struct isl_constraint *constraint)
 357 {
 358         unsigned total;
 359
 360         if (!constraint)
 361                 return;
 362         total = isl_basic_map_total_dim(constraint->bmap);
 363         isl_seq_clr(constraint->line[0], 1 + total);
 364 }
 365
 366 struct isl_constraint *isl_constraint_negate(struct isl_constraint *constraint)
 367 {
 368         unsigned total;
 369
 370         if (!constraint)
 371                 return NULL;
 372
 373         isl_assert(constraint->ctx, !isl_constraint_is_equality(constraint),
 374                         goto error);
 375         isl_assert(constraint->ctx, constraint->bmap->ref == 1, goto error);
 376         total = isl_basic_map_total_dim(constraint->bmap);
 377         isl_seq_neg(constraint->line[0], constraint->line[0], 1 + total);
 378         isl_int_sub_ui(constraint->line[0][0], constraint->line[0][0], 1);
 379         ISL_F_CLR(constraint->bmap, ISL_BASIC_MAP_NORMALIZED);
 380         return constraint;
 381 error:
 382         isl_constraint_free(constraint);
 383         return NULL;
 384 }
 385
 386 int isl_constraint_is_equality(struct isl_constraint *constraint)
 387 {
 388         if (!constraint)
 389                 return -1;
 390         return constraint->line >= constraint->bmap->eq;
 391 }
 392
 393 int isl_constraint_is_div_constraint(__isl_keep isl_constraint *constraint)
 394 {
 395         int i;
 396
 397         if (!constraint)
 398                 return -1;
 399         if (isl_constraint_is_equality(constraint))
 400                 return 0;
 401         for (i = 0; i < constraint->bmap->n_div; ++i) {
 402                 if (isl_int_is_zero(constraint->bmap->div[i][0]))
 403                         continue;
 404                 if (isl_basic_map_is_div_constraint(constraint->bmap,
 405                                         constraint->line[0], i))
 406                         return 1;
 407         }
 408
 409         return 0;
 410 }
 411
 412 /* We manually set ISL_BASIC_SET_FINAL instead of calling
 413  * isl_basic_map_finalize because we want to keep the position
 414  * of the divs and we therefore do not want to throw away redundant divs.
 415  * This is arguably a bit fragile.
 416  */
 417 __isl_give isl_basic_map *isl_basic_map_from_constraint(
 418         __isl_take isl_constraint *constraint)
 419 {
 420         int k;
 421         struct isl_basic_map *bmap;
 422         isl_int *c;
 423         unsigned total;
 424
 425         if (!constraint)
 426                 return NULL;
 427
 428         if (constraint->bmap->n_eq == 1 && constraint->bmap->n_ineq == 0) {
 429                 bmap = isl_basic_map_copy(constraint->bmap);
 430                 isl_constraint_free(constraint);
 431                 return bmap;
 432         }
 433
 434         bmap = isl_basic_map_universe_like(constraint->bmap);
 435         bmap = isl_basic_map_align_divs(bmap, constraint->bmap);
 436         bmap = isl_basic_map_cow(bmap);
 437         bmap = isl_basic_map_extend_constraints(bmap, 1, 1);
 438         if (isl_constraint_is_equality(constraint)) {
 439                 k = isl_basic_map_alloc_equality(bmap);
 440                 if (k < 0)
 441                         goto error;
 442                 c = bmap->eq[k];
 443         }
 444         else {
 445                 k = isl_basic_map_alloc_inequality(bmap);
 446                 if (k < 0)
 447                         goto error;
 448                 c = bmap->ineq[k];
 449         }
 450         total = isl_basic_map_total_dim(bmap);
 451         isl_seq_cpy(c, constraint->line[0], 1 + total);
 452         isl_constraint_free(constraint);
 453         if (bmap)
 454                 ISL_F_SET(bmap, ISL_BASIC_SET_FINAL);
 455         return bmap;
 456 error:
 457         isl_constraint_free(constraint);
 458         isl_basic_map_free(bmap);
 459         return NULL;
 460 }
 461
 462 struct isl_basic_set *isl_basic_set_from_constraint(
 463         struct isl_constraint *constraint)
 464 {
 465         if (!constraint)
 466                 return NULL;
 467
 468         isl_assert(constraint->ctx,n(constraint, isl_dim_in) == 0, goto error);
 469         return (isl_basic_set *)isl_basic_map_from_constraint(constraint);
 470 error:
 471         isl_constraint_free(constraint);
 472         return NULL;
 473 }
 474
 475 int isl_basic_set_has_defining_equality(
 476         struct isl_basic_set *bset, enum isl_dim_type type, int pos,
 477         struct isl_constraint **c)
 478 {
 479         int i;
 480         unsigned offset;
 481         unsigned total;
 482
 483         if (!bset)
 484                 return -1;
 485         offset = basic_set_offset(bset, type);
 486         total = isl_basic_set_total_dim(bset);
 487         isl_assert(bset->ctx, pos < isl_basic_set_dim(bset, type), return -1);
 488         for (i = 0; i < bset->n_eq; ++i)
 489                 if (!isl_int_is_zero(bset->eq[i][offset + pos]) &&
 490                     isl_seq_first_non_zero(bset->eq[i]+offset+pos+1,
 491                                            1+total-offset-pos-1) == -1) {
 492                         *c= isl_basic_set_constraint(isl_basic_set_copy(bset),
 493                                                                 &bset->eq[i]);
 494                         return 1;
 495                 }
 496         return 0;
 497 }
 498
 499 int isl_basic_set_has_defining_inequalities(
 500         struct isl_basic_set *bset, enum isl_dim_type type, int pos,
 501         struct isl_constraint **lower,
 502         struct isl_constraint **upper)
 503 {
 504         int i, j;
 505         unsigned offset;
 506         unsigned total;
 507         isl_int m;
 508         isl_int **lower_line, **upper_line;
 509
 510         if (!bset)
 511                 return -1;
 512         offset = basic_set_offset(bset, type);
 513         total = isl_basic_set_total_dim(bset);
 514         isl_assert(bset->ctx, pos < isl_basic_set_dim(bset, type), return -1);
 515         isl_int_init(m);
 516         for (i = 0; i < bset->n_ineq; ++i) {
 517                 if (isl_int_is_zero(bset->ineq[i][offset + pos]))
 518                         continue;
 519                 if (isl_int_is_one(bset->ineq[i][offset + pos]))
 520                         continue;
 521                 if (isl_int_is_negone(bset->ineq[i][offset + pos]))
 522                         continue;
 523                 if (isl_seq_first_non_zero(bset->ineq[i]+offset+pos+1,
 524                                                 1+total-offset-pos-1) != -1)
 525                         continue;
 526                 for (j = i + 1; j < bset->n_ineq; ++j) {
 527                         if (!isl_seq_is_neg(bset->ineq[i]+1, bset->ineq[j]+1,
 528                                             total))
 529                                 continue;
 530                         isl_int_add(m, bset->ineq[i][0], bset->ineq[j][0]);
 531                         if (isl_int_abs_ge(m, bset->ineq[i][offset+pos]))
 532                                 continue;
 533
 534                         if (isl_int_is_pos(bset->ineq[i][offset+pos])) {
 535                                 lower_line = &bset->ineq[i];
 536                                 upper_line = &bset->ineq[j];
 537                         } else {
 538                                 lower_line = &bset->ineq[j];
 539                                 upper_line = &bset->ineq[i];
 540                         }
 541                         *lower = isl_basic_set_constraint(
 542                                         isl_basic_set_copy(bset), lower_line);
 543                         *upper = isl_basic_set_constraint(
 544                                         isl_basic_set_copy(bset), upper_line);
 545                         isl_int_clear(m);
 546                         return 1;
 547                 }
 548         }
 549         *lower = NULL;
 550         *upper = NULL;
 551         isl_int_clear(m);
 552         return 0;
 553 }
 554
 555 /* Given two constraints "a" and "b" on the variable at position "abs_pos"
 556  * (in "a" and "b"), add a constraint to "bset" that ensures that the
 557  * bound implied by "a" is (strictly) larger than the bound implied by "b".
 558  *
 559  * If both constraints imply lower bounds, then this means that "a" is
 560  * active in the result.
 561  * If both constraints imply upper bounds, then this means that "b" is
 562  * active in the result.
 563  */
 564 static __isl_give isl_basic_set *add_larger_bound_constraint(
 565         __isl_take isl_basic_set *bset, isl_int *a, isl_int *b,
 566         unsigned abs_pos, int strict)
 567 {
 568         int k;
 569         isl_int t;
 570         unsigned total;
 571
 572         k = isl_basic_set_alloc_inequality(bset);
 573         if (k < 0)
 574                 goto error;
 575
 576         total = isl_basic_set_dim(bset, isl_dim_all);
 577
 578         isl_int_init(t);
 579         isl_int_neg(t, b[1 + abs_pos]);
 580
 581         isl_seq_combine(bset->ineq[k], t, a, a[1 + abs_pos], b, 1 + abs_pos);
 582         isl_seq_combine(bset->ineq[k] + 1 + abs_pos,
 583                 t, a + 1 + abs_pos + 1, a[1 + abs_pos], b + 1 + abs_pos + 1,
 584                 total - abs_pos);
 585
 586         if (strict)
 587                 isl_int_sub_ui(bset->ineq[k][0], bset->ineq[k][0], 1);
 588
 589         isl_int_clear(t);
 590
 591         return bset;
 592 error:
 593         isl_basic_set_free(bset);
 594         return NULL;
 595 }
 596
 597 /* Add constraints to "context" that ensure that "u" is the smallest
 598  * (and therefore active) upper bound on "abs_pos" in "bset" and return
 599  * the resulting basic set.
 600  */
 601 static __isl_give isl_basic_set *set_smallest_upper_bound(
 602         __isl_keep isl_basic_set *context,
 603         __isl_keep isl_basic_set *bset, unsigned abs_pos, int n_upper, int u)
 604 {
 605         int j;
 606
 607         context = isl_basic_set_copy(context);
 608         context = isl_basic_set_cow(context);
 609
 610         context = isl_basic_set_extend_constraints(context, 0, n_upper - 1);
 611
 612         for (j = 0; j < bset->n_ineq; ++j) {
 613                 if (j == u)
 614                         continue;
 615                 if (!isl_int_is_neg(bset->ineq[j][1 + abs_pos]))
 616                         continue;
 617                 context = add_larger_bound_constraint(context,
 618                         bset->ineq[j], bset->ineq[u], abs_pos, j > u);
 619         }
 620
 621         context = isl_basic_set_simplify(context);
 622         context = isl_basic_set_finalize(context);
 623
 624         return context;
 625 }
 626
 627 /* Add constraints to "context" that ensure that "u" is the largest
 628  * (and therefore active) upper bound on "abs_pos" in "bset" and return
 629  * the resulting basic set.
 630  */
 631 static __isl_give isl_basic_set *set_largest_lower_bound(
 632         __isl_keep isl_basic_set *context,
 633         __isl_keep isl_basic_set *bset, unsigned abs_pos, int n_lower, int l)
 634 {
 635         int j;
 636
 637         context = isl_basic_set_copy(context);
 638         context = isl_basic_set_cow(context);
 639
 640         context = isl_basic_set_extend_constraints(context, 0, n_lower - 1);
 641
 642         for (j = 0; j < bset->n_ineq; ++j) {
 643                 if (j == l)
 644                         continue;
 645                 if (!isl_int_is_pos(bset->ineq[j][1 + abs_pos]))
 646                         continue;
 647                 context = add_larger_bound_constraint(context,
 648                         bset->ineq[l], bset->ineq[j], abs_pos, j > l);
 649         }
 650
 651         context = isl_basic_set_simplify(context);
 652         context = isl_basic_set_finalize(context);
 653
 654         return context;
 655 }
 656
 657 static int foreach_upper_bound(__isl_keep isl_basic_set *bset,
 658         enum isl_dim_type type, unsigned abs_pos,
 659         __isl_take isl_basic_set *context, int n_upper,
 660         int (*fn)(__isl_take isl_constraint *lower,
 661                   __isl_take isl_constraint *upper,
 662                   __isl_take isl_basic_set *bset, void *user), void *user)
 663 {
 664         isl_basic_set *context_i;
 665         isl_constraint *upper = NULL;
 666         int i;
 667
 668         for (i = 0; i < bset->n_ineq; ++i) {
 669                 if (isl_int_is_zero(bset->ineq[i][1 + abs_pos]))
 670                         continue;
 671
 672                 context_i = set_smallest_upper_bound(context, bset,
 673                                                         abs_pos, n_upper, i);
 674                 if (isl_basic_set_is_empty(context_i)) {
 675                         isl_basic_set_free(context_i);
 676                         continue;
 677                 }
 678                 upper = isl_basic_set_constraint(isl_basic_set_copy(bset),
 679                                                 &bset->ineq[i]);
 680                 if (!upper || !context_i)
 681                         goto error;
 682                 if (fn(NULL, upper, context_i, user) < 0)
 683                         break;
 684         }
 685
 686         isl_basic_set_free(context);
 687
 688         if (i < bset->n_ineq)
 689                 return -1;
 690
 691         return 0;
 692 error:
 693         isl_constraint_free(upper);
 694         isl_basic_set_free(context_i);
 695         isl_basic_set_free(context);
 696         return -1;
 697 }
 698
 699 static int foreach_lower_bound(__isl_keep isl_basic_set *bset,
 700         enum isl_dim_type type, unsigned abs_pos,
 701         __isl_take isl_basic_set *context, int n_lower,
 702         int (*fn)(__isl_take isl_constraint *lower,
 703                   __isl_take isl_constraint *upper,
 704                   __isl_take isl_basic_set *bset, void *user), void *user)
 705 {
 706         isl_basic_set *context_i;
 707         isl_constraint *lower = NULL;
 708         int i;
 709
 710         for (i = 0; i < bset->n_ineq; ++i) {
 711                 if (isl_int_is_zero(bset->ineq[i][1 + abs_pos]))
 712                         continue;
 713
 714                 context_i = set_largest_lower_bound(context, bset,
 715                                                         abs_pos, n_lower, i);
 716                 if (isl_basic_set_is_empty(context_i)) {
 717                         isl_basic_set_free(context_i);
 718                         continue;
 719                 }
 720                 lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
 721                                                 &bset->ineq[i]);
 722                 if (!lower || !context_i)
 723                         goto error;
 724                 if (fn(lower, NULL, context_i, user) < 0)
 725                         break;
 726         }
 727
 728         isl_basic_set_free(context);
 729
 730         if (i < bset->n_ineq)
 731                 return -1;
 732
 733         return 0;
 734 error:
 735         isl_constraint_free(lower);
 736         isl_basic_set_free(context_i);
 737         isl_basic_set_free(context);
 738         return -1;
 739 }
 740
 741 static int foreach_bound_pair(__isl_keep isl_basic_set *bset,
 742         enum isl_dim_type type, unsigned abs_pos,
 743         __isl_take isl_basic_set *context, int n_lower, int n_upper,
 744         int (*fn)(__isl_take isl_constraint *lower,
 745                   __isl_take isl_constraint *upper,
 746                   __isl_take isl_basic_set *bset, void *user), void *user)
 747 {
 748         isl_basic_set *context_i, *context_j;
 749         isl_constraint *lower = NULL;
 750         isl_constraint *upper = NULL;
 751         int i, j;
 752
 753         for (i = 0; i < bset->n_ineq; ++i) {
 754                 if (!isl_int_is_pos(bset->ineq[i][1 + abs_pos]))
 755                         continue;
 756
 757                 context_i = set_largest_lower_bound(context, bset,
 758                                                         abs_pos, n_lower, i);
 759                 if (isl_basic_set_is_empty(context_i)) {
 760                         isl_basic_set_free(context_i);
 761                         continue;
 762                 }
 763
 764                 for (j = 0; j < bset->n_ineq; ++j) {
 765                         if (!isl_int_is_neg(bset->ineq[j][1 + abs_pos]))
 766                                 continue;
 767
 768                         context_j = set_smallest_upper_bound(context_i, bset,
 769                                                             abs_pos, n_upper, j);
 770                         context_j = isl_basic_set_extend_constraints(context_j,
 771                                                                         0, 1);
 772                         context_j = add_larger_bound_constraint(context_j,
 773                                 bset->ineq[i], bset->ineq[j], abs_pos, 0);
 774                         context_j = isl_basic_set_simplify(context_j);
 775                         context_j = isl_basic_set_finalize(context_j);
 776                         if (isl_basic_set_is_empty(context_j)) {
 777                                 isl_basic_set_free(context_j);
 778                                 continue;
 779                         }
 780                         lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
 781                                                         &bset->ineq[i]);
 782                         upper = isl_basic_set_constraint(isl_basic_set_copy(bset),
 783                                                         &bset->ineq[j]);
 784                         if (!lower || !upper || !context_j)
 785                                 goto error;
 786                         if (fn(lower, upper, context_j, user) < 0)
 787                                 break;
 788                 }
 789
 790                 isl_basic_set_free(context_i);
 791
 792                 if (j < bset->n_ineq)
 793                         break;
 794         }
 795
 796         isl_basic_set_free(context);
 797
 798         if (i < bset->n_ineq)
 799                 return -1;
 800
 801         return 0;
 802 error:
 803         isl_constraint_free(lower);
 804         isl_constraint_free(upper);
 805         isl_basic_set_free(context_i);
 806         isl_basic_set_free(context_j);
 807         isl_basic_set_free(context);
 808         return -1;
 809 }
 810
 811 /* For each pair of lower and upper bounds on the variable "pos"
 812  * of type "type", call "fn" with these lower and upper bounds and the
 813  * set of constraints on the remaining variables where these bounds
 814  * are active, i.e., (stricly) larger/smaller than the other lower/upper bounds.
 815  *
 816  * If the designated variable is equal to an affine combination of the
 817  * other variables then fn is called with both lower and upper
 818  * set to the corresponding equality.
 819  *
 820  * If there is no lower (or upper) bound, then NULL is passed
 821  * as the corresponding bound.
 822  *
 823  * We first check if the variable is involved in any equality.
 824  * If not, we count the number of lower and upper bounds and
 825  * act accordingly.
 826  */
 827 int isl_basic_set_foreach_bound_pair(__isl_keep isl_basic_set *bset,
 828         enum isl_dim_type type, unsigned pos,
 829         int (*fn)(__isl_take isl_constraint *lower,
 830                   __isl_take isl_constraint *upper,
 831                   __isl_take isl_basic_set *bset, void *user), void *user)
 832 {
 833         int i;
 834         isl_constraint *lower = NULL;
 835         isl_constraint *upper = NULL;
 836         isl_basic_set *context = NULL;
 837         unsigned abs_pos;
 838         int n_lower, n_upper;
 839
 840         if (!bset)
 841                 return -1;
 842         isl_assert(bset->ctx, pos < isl_basic_set_dim(bset, type), return -1);
 843         isl_assert(bset->ctx, type == isl_dim_param || type == isl_dim_set,
 844                 return -1);
 845
 846         abs_pos = pos;
 847         if (type == isl_dim_set)
 848                 abs_pos += isl_basic_set_dim(bset, isl_dim_param);
 849
 850         for (i = 0; i < bset->n_eq; ++i) {
 851                 if (isl_int_is_zero(bset->eq[i][1 + abs_pos]))
 852                         continue;
 853
 854                 lower = isl_basic_set_constraint(isl_basic_set_copy(bset),
 855                                                 &bset->eq[i]);
 856                 upper = isl_constraint_copy(lower);
 857                 context = isl_basic_set_remove(isl_basic_set_copy(bset),
 858                                         type, pos, 1);
 859                 if (!lower || !upper || !context)
 860                         goto error;
 861                 return fn(lower, upper, context, user);
 862         }
 863
 864         n_lower = 0;
 865         n_upper = 0;
 866         for (i = 0; i < bset->n_ineq; ++i) {
 867                 if (isl_int_is_pos(bset->ineq[i][1 + abs_pos]))
 868                         n_lower++;
 869                 else if (isl_int_is_neg(bset->ineq[i][1 + abs_pos]))
 870                         n_upper++;
 871         }
 872
 873         context = isl_basic_set_copy(bset);
 874         context = isl_basic_set_cow(context);
 875         if (!context)
 876                 goto error;
 877         for (i = context->n_ineq - 1; i >= 0; --i)
 878                 if (!isl_int_is_zero(context->ineq[i][1 + abs_pos]))
 879                         isl_basic_set_drop_inequality(context, i);
 880
 881         context = isl_basic_set_drop(context, type, pos, 1);
 882         if (!n_lower && !n_upper)
 883                 return fn(NULL, NULL, context, user);
 884         if (!n_lower)
 885                 return foreach_upper_bound(bset, type, abs_pos, context, n_upper,
 886                                                 fn, user);
 887         if (!n_upper)
 888                 return foreach_lower_bound(bset, type, abs_pos, context, n_lower,
 889                                                 fn, user);
 890         return foreach_bound_pair(bset, type, abs_pos, context, n_lower, n_upper,
 891                                         fn, user);
 892 error:
 893         isl_constraint_free(lower);
 894         isl_constraint_free(upper);
 895         isl_basic_set_free(context);
 896         return -1;
 897 }