isl_local_space.c

   1 /*
   2  * Copyright 2011      INRIA Saclay
   3  *
   4  * Use of this software is governed by the GNU LGPLv2.1 license
   5  *
   6  * Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
   7  * Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
   8  * 91893 Orsay, France
   9  */
  10
  11 #include <isl_ctx_private.h>
  12 #include <isl_map_private.h>
  13 #include <isl_local_space_private.h>
  14 #include <isl_space_private.h>
  15 #include <isl_mat_private.h>
  16 #include <isl_aff_private.h>
  17 #include <isl/seq.h>
  18
  19 isl_ctx *isl_local_space_get_ctx(__isl_keep isl_local_space *ls)
  20 {
  21         return ls ? ls->dim->ctx : NULL;
  22 }
  23
  24 __isl_give isl_local_space *isl_local_space_alloc_div(__isl_take isl_space *dim,
  25         __isl_take isl_mat *div)
  26 {
  27         isl_ctx *ctx;
  28         isl_local_space *ls = NULL;
  29
  30         if (!dim || !div)
  31                 goto error;
  32
  33         ctx = isl_space_get_ctx(dim);
  34         ls = isl_calloc_type(ctx, struct isl_local_space);
  35         if (!ls)
  36                 goto error;
  37
  38         ls->ref = 1;
  39         ls->dim = dim;
  40         ls->div = div;
  41
  42         return ls;
  43 error:
  44         isl_mat_free(div);
  45         isl_space_free(dim);
  46         isl_local_space_free(ls);
  47         return NULL;
  48 }
  49
  50 __isl_give isl_local_space *isl_local_space_alloc(__isl_take isl_space *dim,
  51         unsigned n_div)
  52 {
  53         isl_ctx *ctx;
  54         isl_mat *div;
  55         unsigned total;
  56
  57         if (!dim)
  58                 return NULL;
  59
  60         total = isl_space_dim(dim, isl_dim_all);
  61
  62         ctx = isl_space_get_ctx(dim);
  63         div = isl_mat_alloc(ctx, n_div, 1 + 1 + total + n_div);
  64         return isl_local_space_alloc_div(dim, div);
  65 }
  66
  67 __isl_give isl_local_space *isl_local_space_from_space(__isl_take isl_space *dim)
  68 {
  69         return isl_local_space_alloc(dim, 0);
  70 }
  71
  72 __isl_give isl_local_space *isl_local_space_copy(__isl_keep isl_local_space *ls)
  73 {
  74         if (!ls)
  75                 return NULL;
  76
  77         ls->ref++;
  78         return ls;
  79 }
  80
  81 __isl_give isl_local_space *isl_local_space_dup(__isl_keep isl_local_space *ls)
  82 {
  83         if (!ls)
  84                 return NULL;
  85
  86         return isl_local_space_alloc_div(isl_space_copy(ls->dim),
  87                                          isl_mat_copy(ls->div));
  88
  89 }
  90
  91 __isl_give isl_local_space *isl_local_space_cow(__isl_take isl_local_space *ls)
  92 {
  93         if (!ls)
  94                 return NULL;
  95
  96         if (ls->ref == 1)
  97                 return ls;
  98         ls->ref--;
  99         return isl_local_space_dup(ls);
 100 }
 101
 102 void *isl_local_space_free(__isl_take isl_local_space *ls)
 103 {
 104         if (!ls)
 105                 return NULL;
 106
 107         if (--ls->ref > 0)
 108                 return NULL;
 109
 110         isl_space_free(ls->dim);
 111         isl_mat_free(ls->div);
 112
 113         free(ls);
 114
 115         return NULL;
 116 }
 117
 118 /* Is the local space that of a set?
 119  */
 120 int isl_local_space_is_set(__isl_keep isl_local_space *ls)
 121 {
 122         return ls ? isl_space_is_set(ls->dim) : -1;
 123 }
 124
 125 /* Return true if the two local spaces are identical, with identical
 126  * expressions for the integer divisions.
 127  */
 128 int isl_local_space_is_equal(__isl_keep isl_local_space *ls1,
 129         __isl_keep isl_local_space *ls2)
 130 {
 131         int equal;
 132
 133         if (!ls1 || !ls2)
 134                 return -1;
 135
 136         equal = isl_space_is_equal(ls1->dim, ls2->dim);
 137         if (equal < 0 || !equal)
 138                 return equal;
 139
 140         if (!isl_local_space_divs_known(ls1))
 141                 return 0;
 142         if (!isl_local_space_divs_known(ls2))
 143                 return 0;
 144
 145         return isl_mat_is_equal(ls1->div, ls2->div);
 146 }
 147
 148 int isl_local_space_dim(__isl_keep isl_local_space *ls,
 149         enum isl_dim_type type)
 150 {
 151         if (!ls)
 152                 return 0;
 153         if (type == isl_dim_div)
 154                 return ls->div->n_row;
 155         if (type == isl_dim_all)
 156                 return isl_space_dim(ls->dim, isl_dim_all) + ls->div->n_row;
 157         return isl_space_dim(ls->dim, type);
 158 }
 159
 160 unsigned isl_local_space_offset(__isl_keep isl_local_space *ls,
 161         enum isl_dim_type type)
 162 {
 163         isl_space *dim;
 164
 165         if (!ls)
 166                 return 0;
 167
 168         dim = ls->dim;
 169         switch (type) {
 170         case isl_dim_cst:       return 0;
 171         case isl_dim_param:     return 1;
 172         case isl_dim_in:        return 1 + dim->nparam;
 173         case isl_dim_out:       return 1 + dim->nparam + dim->n_in;
 174         case isl_dim_div:       return 1 + dim->nparam + dim->n_in + dim->n_out;
 175         default:                return 0;
 176         }
 177 }
 178
 179 const char *isl_local_space_get_dim_name(__isl_keep isl_local_space *ls,
 180         enum isl_dim_type type, unsigned pos)
 181 {
 182         return ls ? isl_space_get_dim_name(ls->dim, type, pos) : NULL;
 183 }
 184
 185 __isl_give isl_aff *isl_local_space_get_div(__isl_keep isl_local_space *ls,
 186         int pos)
 187 {
 188         isl_aff *aff;
 189
 190         if (!ls)
 191                 return NULL;
 192
 193         if (pos < 0 || pos >= ls->div->n_row)
 194                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 195                         "index out of bounds", return NULL);
 196
 197         if (isl_int_is_zero(ls->div->row[pos][0]))
 198                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 199                         "expression of div unknown", return NULL);
 200
 201         aff = isl_aff_alloc(isl_local_space_copy(ls));
 202         if (!aff)
 203                 return NULL;
 204         isl_seq_cpy(aff->v->el, ls->div->row[pos], aff->v->size);
 205         return aff;
 206 }
 207
 208 __isl_give isl_space *isl_local_space_get_space(__isl_keep isl_local_space *ls)
 209 {
 210         if (!ls)
 211                 return NULL;
 212
 213         return isl_space_copy(ls->dim);
 214 }
 215
 216 __isl_give isl_local_space *isl_local_space_set_dim_name(
 217         __isl_take isl_local_space *ls,
 218         enum isl_dim_type type, unsigned pos, const char *s)
 219 {
 220         ls = isl_local_space_cow(ls);
 221         if (!ls)
 222                 return NULL;
 223         ls->dim = isl_space_set_dim_name(ls->dim, type, pos, s);
 224         if (!ls->dim)
 225                 return isl_local_space_free(ls);
 226
 227         return ls;
 228 }
 229
 230 __isl_give isl_local_space *isl_local_space_set_dim_id(
 231         __isl_take isl_local_space *ls,
 232         enum isl_dim_type type, unsigned pos, __isl_take isl_id *id)
 233 {
 234         ls = isl_local_space_cow(ls);
 235         if (!ls)
 236                 return isl_id_free(id);
 237         ls->dim = isl_space_set_dim_id(ls->dim, type, pos, id);
 238         if (!ls->dim)
 239                 return isl_local_space_free(ls);
 240
 241         return ls;
 242 }
 243
 244 __isl_give isl_local_space *isl_local_space_reset_space(
 245         __isl_take isl_local_space *ls, __isl_take isl_space *dim)
 246 {
 247         ls = isl_local_space_cow(ls);
 248         if (!ls || !dim)
 249                 goto error;
 250
 251         isl_space_free(ls->dim);
 252         ls->dim = dim;
 253
 254         return ls;
 255 error:
 256         isl_local_space_free(ls);
 257         isl_space_free(dim);
 258         return NULL;
 259 }
 260
 261 /* Reorder the columns of the given div definitions according to the
 262  * given reordering.
 263  * The order of the divs themselves is assumed not to change.
 264  */
 265 static __isl_give isl_mat *reorder_divs(__isl_take isl_mat *div,
 266         __isl_take isl_reordering *r)
 267 {
 268         int i, j;
 269         isl_mat *mat;
 270         int extra;
 271
 272         if (!div || !r)
 273                 goto error;
 274
 275         extra = isl_space_dim(r->dim, isl_dim_all) + div->n_row - r->len;
 276         mat = isl_mat_alloc(div->ctx, div->n_row, div->n_col + extra);
 277         if (!mat)
 278                 goto error;
 279
 280         for (i = 0; i < div->n_row; ++i) {
 281                 isl_seq_cpy(mat->row[i], div->row[i], 2);
 282                 isl_seq_clr(mat->row[i] + 2, mat->n_col - 2);
 283                 for (j = 0; j < r->len; ++j)
 284                         isl_int_set(mat->row[i][2 + r->pos[j]],
 285                                     div->row[i][2 + j]);
 286         }
 287
 288         isl_reordering_free(r);
 289         isl_mat_free(div);
 290         return mat;
 291 error:
 292         isl_reordering_free(r);
 293         isl_mat_free(div);
 294         return NULL;
 295 }
 296
 297 /* Reorder the dimensions of "ls" according to the given reordering.
 298  * The reordering r is assumed to have been extended with the local
 299  * variables, leaving them in the same order.
 300  */
 301 __isl_give isl_local_space *isl_local_space_realign(
 302         __isl_take isl_local_space *ls, __isl_take isl_reordering *r)
 303 {
 304         ls = isl_local_space_cow(ls);
 305         if (!ls || !r)
 306                 goto error;
 307
 308         ls->div = reorder_divs(ls->div, isl_reordering_copy(r));
 309         if (!ls->div)
 310                 goto error;
 311
 312         ls = isl_local_space_reset_space(ls, isl_space_copy(r->dim));
 313
 314         isl_reordering_free(r);
 315         return ls;
 316 error:
 317         isl_local_space_free(ls);
 318         isl_reordering_free(r);
 319         return NULL;
 320 }
 321
 322 __isl_give isl_local_space *isl_local_space_add_div(
 323         __isl_take isl_local_space *ls, __isl_take isl_vec *div)
 324 {
 325         ls = isl_local_space_cow(ls);
 326         if (!ls || !div)
 327                 goto error;
 328
 329         if (ls->div->n_col != div->size)
 330                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 331                         "incompatible dimensions", goto error);
 332
 333         ls->div = isl_mat_add_zero_cols(ls->div, 1);
 334         ls->div = isl_mat_add_rows(ls->div, 1);
 335         if (!ls->div)
 336                 goto error;
 337
 338         isl_seq_cpy(ls->div->row[ls->div->n_row - 1], div->el, div->size);
 339         isl_int_set_si(ls->div->row[ls->div->n_row - 1][div->size], 0);
 340
 341         isl_vec_free(div);
 342         return ls;
 343 error:
 344         isl_local_space_free(ls);
 345         isl_vec_free(div);
 346         return NULL;
 347 }
 348
 349 __isl_give isl_local_space *isl_local_space_replace_divs(
 350         __isl_take isl_local_space *ls, __isl_take isl_mat *div)
 351 {
 352         ls = isl_local_space_cow(ls);
 353
 354         if (!ls || !div)
 355                 goto error;
 356
 357         isl_mat_free(ls->div);
 358         ls->div = div;
 359         return ls;
 360 error:
 361         isl_mat_free(div);
 362         isl_local_space_free(ls);
 363         return NULL;
 364 }
 365
 366 /* Copy row "s" of "src" to row "d" of "dst", applying the expansion
 367  * defined by "exp".
 368  */
 369 static void expand_row(__isl_keep isl_mat *dst, int d,
 370         __isl_keep isl_mat *src, int s, int *exp)
 371 {
 372         int i;
 373         unsigned c = src->n_col - src->n_row;
 374
 375         isl_seq_cpy(dst->row[d], src->row[s], c);
 376         isl_seq_clr(dst->row[d] + c, dst->n_col - c);
 377
 378         for (i = 0; i < s; ++i)
 379                 isl_int_set(dst->row[d][c + exp[i]], src->row[s][c + i]);
 380 }
 381
 382 /* Compare (known) divs.
 383  * Return non-zero if at least one of the two divs is unknown.
 384  */
 385 static int cmp_row(__isl_keep isl_mat *div, int i, int j)
 386 {
 387         int li, lj;
 388
 389         if (isl_int_is_zero(div->row[j][0]))
 390                 return -1;
 391         if (isl_int_is_zero(div->row[i][0]))
 392                 return 1;
 393
 394         li = isl_seq_last_non_zero(div->row[i], div->n_col);
 395         lj = isl_seq_last_non_zero(div->row[j], div->n_col);
 396
 397         if (li != lj)
 398                 return li - lj;
 399
 400         return isl_seq_cmp(div->row[i], div->row[j], div->n_col);
 401 }
 402
 403 /* Combine the two lists of divs into a single list.
 404  * For each row i in div1, exp1[i] is set to the position of the corresponding
 405  * row in the result.  Similarly for div2 and exp2.
 406  * This function guarantees
 407  *      exp1[i] >= i
 408  *      exp1[i+1] > exp1[i]
 409  * For optimal merging, the two input list should have been sorted.
 410  */
 411 __isl_give isl_mat *isl_merge_divs(__isl_keep isl_mat *div1,
 412         __isl_keep isl_mat *div2, int *exp1, int *exp2)
 413 {
 414         int i, j, k;
 415         isl_mat *div = NULL;
 416         unsigned d = div1->n_col - div1->n_row;
 417
 418         div = isl_mat_alloc(div1->ctx, 1 + div1->n_row + div2->n_row,
 419                                 d + div1->n_row + div2->n_row);
 420         if (!div)
 421                 return NULL;
 422
 423         for (i = 0, j = 0, k = 0; i < div1->n_row && j < div2->n_row; ++k) {
 424                 int cmp;
 425
 426                 expand_row(div, k, div1, i, exp1);
 427                 expand_row(div, k + 1, div2, j, exp2);
 428
 429                 cmp = cmp_row(div, k, k + 1);
 430                 if (cmp == 0) {
 431                         exp1[i++] = k;
 432                         exp2[j++] = k;
 433                 } else if (cmp < 0) {
 434                         exp1[i++] = k;
 435                 } else {
 436                         exp2[j++] = k;
 437                         isl_seq_cpy(div->row[k], div->row[k + 1], div->n_col);
 438                 }
 439         }
 440         for (; i < div1->n_row; ++i, ++k) {
 441                 expand_row(div, k, div1, i, exp1);
 442                 exp1[i] = k;
 443         }
 444         for (; j < div2->n_row; ++j, ++k) {
 445                 expand_row(div, k, div2, j, exp2);
 446                 exp2[j] = k;
 447         }
 448
 449         div->n_row = k;
 450         div->n_col = d + k;
 451
 452         return div;
 453 }
 454
 455 /* Construct a local space that contains all the divs in either
 456  * "ls1" or "ls2".
 457  */
 458 __isl_give isl_local_space *isl_local_space_intersect(
 459         __isl_take isl_local_space *ls1, __isl_take isl_local_space *ls2)
 460 {
 461         isl_ctx *ctx;
 462         int *exp1 = NULL;
 463         int *exp2 = NULL;
 464         isl_mat *div;
 465
 466         if (!ls1 || !ls2)
 467                 goto error;
 468
 469         ctx = isl_local_space_get_ctx(ls1);
 470         if (!isl_space_is_equal(ls1->dim, ls2->dim))
 471                 isl_die(ctx, isl_error_invalid,
 472                         "spaces should be identical", goto error);
 473
 474         if (ls2->div->n_row == 0) {
 475                 isl_local_space_free(ls2);
 476                 return ls1;
 477         }
 478
 479         if (ls1->div->n_row == 0) {
 480                 isl_local_space_free(ls1);
 481                 return ls2;
 482         }
 483
 484         exp1 = isl_alloc_array(ctx, int, ls1->div->n_row);
 485         exp2 = isl_alloc_array(ctx, int, ls2->div->n_row);
 486         if (!exp1 || !exp2)
 487                 goto error;
 488
 489         div = isl_merge_divs(ls1->div, ls2->div, exp1, exp2);
 490         if (!div)
 491                 goto error;
 492
 493         free(exp1);
 494         free(exp2);
 495         isl_local_space_free(ls2);
 496         isl_mat_free(ls1->div);
 497         ls1->div = div;
 498
 499         return ls1;
 500 error:
 501         free(exp1);
 502         free(exp2);
 503         isl_local_space_free(ls1);
 504         isl_local_space_free(ls2);
 505         return NULL;
 506 }
 507
 508 int isl_local_space_divs_known(__isl_keep isl_local_space *ls)
 509 {
 510         int i;
 511
 512         if (!ls)
 513                 return -1;
 514
 515         for (i = 0; i < ls->div->n_row; ++i)
 516                 if (isl_int_is_zero(ls->div->row[i][0]))
 517                         return 0;
 518
 519         return 1;
 520 }
 521
 522 __isl_give isl_local_space *isl_local_space_domain(
 523         __isl_take isl_local_space *ls)
 524 {
 525         ls = isl_local_space_drop_dims(ls, isl_dim_out,
 526                                         0, isl_local_space_dim(ls, isl_dim_out));
 527         ls = isl_local_space_cow(ls);
 528         if (!ls)
 529                 return NULL;
 530         ls->dim = isl_space_domain(ls->dim);
 531         if (!ls->dim)
 532                 return isl_local_space_free(ls);
 533         return ls;
 534 }
 535
 536 __isl_give isl_local_space *isl_local_space_range(
 537         __isl_take isl_local_space *ls)
 538 {
 539         ls = isl_local_space_drop_dims(ls, isl_dim_in,
 540                                         0, isl_local_space_dim(ls, isl_dim_in));
 541         ls = isl_local_space_cow(ls);
 542         if (!ls)
 543                 return NULL;
 544
 545         ls->dim = isl_space_range(ls->dim);
 546         if (!ls->dim)
 547                 return isl_local_space_free(ls);
 548         return ls;
 549 }
 550
 551 /* Construct a local space for a map that has the given local
 552  * space as domain and that has a zero-dimensional range.
 553  */
 554 __isl_give isl_local_space *isl_local_space_from_domain(
 555         __isl_take isl_local_space *ls)
 556 {
 557         ls = isl_local_space_cow(ls);
 558         if (!ls)
 559                 return NULL;
 560         ls->dim = isl_space_from_domain(ls->dim);
 561         if (!ls->dim)
 562                 return isl_local_space_free(ls);
 563         return ls;
 564 }
 565
 566 __isl_give isl_local_space *isl_local_space_add_dims(
 567         __isl_take isl_local_space *ls, enum isl_dim_type type, unsigned n)
 568 {
 569         int pos;
 570
 571         if (!ls)
 572                 return NULL;
 573         pos = isl_local_space_dim(ls, type);
 574         return isl_local_space_insert_dims(ls, type, pos, n);
 575 }
 576
 577 /* Remove common factor of non-constant terms and denominator.
 578  */
 579 static void normalize_div(__isl_keep isl_local_space *ls, int div)
 580 {
 581         isl_ctx *ctx = ls->div->ctx;
 582         unsigned total = ls->div->n_col - 2;
 583
 584         isl_seq_gcd(ls->div->row[div] + 2, total, &ctx->normalize_gcd);
 585         isl_int_gcd(ctx->normalize_gcd,
 586                     ctx->normalize_gcd, ls->div->row[div][0]);
 587         if (isl_int_is_one(ctx->normalize_gcd))
 588                 return;
 589
 590         isl_seq_scale_down(ls->div->row[div] + 2, ls->div->row[div] + 2,
 591                             ctx->normalize_gcd, total);
 592         isl_int_divexact(ls->div->row[div][0], ls->div->row[div][0],
 593                             ctx->normalize_gcd);
 594         isl_int_fdiv_q(ls->div->row[div][1], ls->div->row[div][1],
 595                             ctx->normalize_gcd);
 596 }
 597
 598 /* Exploit the equalities in "eq" to simplify the expressions of
 599  * the integer divisions in "ls".
 600  * The integer divisions in "ls" are assumed to appear as regular
 601  * dimensions in "eq".
 602  */
 603 __isl_give isl_local_space *isl_local_space_substitute_equalities(
 604         __isl_take isl_local_space *ls, __isl_take isl_basic_set *eq)
 605 {
 606         int i, j, k;
 607         unsigned total;
 608         unsigned n_div;
 609
 610         ls = isl_local_space_cow(ls);
 611         if (!ls || !eq)
 612                 goto error;
 613
 614         total = isl_space_dim(eq->dim, isl_dim_all);
 615         if (isl_local_space_dim(ls, isl_dim_all) != total)
 616                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 617                         "dimensions don't match", goto error);
 618         total++;
 619         n_div = eq->n_div;
 620         for (i = 0; i < eq->n_eq; ++i) {
 621                 j = isl_seq_last_non_zero(eq->eq[i], total + n_div);
 622                 if (j < 0 || j == 0 || j >= total)
 623                         continue;
 624
 625                 for (k = 0; k < ls->div->n_row; ++k) {
 626                         if (isl_int_is_zero(ls->div->row[k][1 + j]))
 627                                 continue;
 628                         isl_seq_elim(ls->div->row[k] + 1, eq->eq[i], j, total,
 629                                         &ls->div->row[k][0]);
 630                         normalize_div(ls, k);
 631                 }
 632         }
 633
 634         isl_basic_set_free(eq);
 635         return ls;
 636 error:
 637         isl_basic_set_free(eq);
 638         isl_local_space_free(ls);
 639         return NULL;
 640 }
 641
 642 /* Plug in "subs" for dimension "type", "pos" in the integer divisions
 643  * of "ls".
 644  *
 645  * Let i be the dimension to replace and let "subs" be of the form
 646  *
 647  *      f/d
 648  *
 649  * Any integer division with a non-zero coefficient for i,
 650  *
 651  *      floor((a i + g)/m)
 652  *
 653  * is replaced by
 654  *
 655  *      floor((a f + d g)/(m d))
 656  */
 657 __isl_give isl_local_space *isl_local_space_substitute(
 658         __isl_take isl_local_space *ls,
 659         enum isl_dim_type type, unsigned pos, __isl_keep isl_aff *subs)
 660 {
 661         int i;
 662         isl_int v;
 663
 664         ls = isl_local_space_cow(ls);
 665         if (!ls || !subs)
 666                 return isl_local_space_free(ls);
 667
 668         if (!isl_space_is_equal(ls->dim, subs->ls->dim))
 669                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 670                         "spaces don't match", return isl_local_space_free(ls));
 671         if (isl_local_space_dim(subs->ls, isl_dim_div) != 0)
 672                 isl_die(isl_local_space_get_ctx(ls), isl_error_unsupported,
 673                         "cannot handle divs yet",
 674                         return isl_local_space_free(ls));
 675
 676         pos += isl_local_space_offset(ls, type);
 677
 678         isl_int_init(v);
 679         for (i = 0; i < ls->div->n_row; ++i) {
 680                 if (isl_int_is_zero(ls->div->row[i][1 + pos]))
 681                         continue;
 682                 isl_int_set(v, ls->div->row[i][1 + pos]);
 683                 isl_int_set_si(ls->div->row[i][1 + pos], 0);
 684                 isl_seq_combine(ls->div->row[i] + 1,
 685                                 subs->v->el[0], ls->div->row[i] + 1,
 686                                 v, subs->v->el + 1, subs->v->size - 1);
 687                 isl_int_mul(ls->div->row[i][0],
 688                             ls->div->row[i][0], subs->v->el[0]);
 689                 normalize_div(ls, i);
 690         }
 691         isl_int_clear(v);
 692
 693         return ls;
 694 }
 695
 696 int isl_local_space_is_named_or_nested(__isl_keep isl_local_space *ls,
 697         enum isl_dim_type type)
 698 {
 699         if (!ls)
 700                 return -1;
 701         return isl_space_is_named_or_nested(ls->dim, type);
 702 }
 703
 704 __isl_give isl_local_space *isl_local_space_drop_dims(
 705         __isl_take isl_local_space *ls,
 706         enum isl_dim_type type, unsigned first, unsigned n)
 707 {
 708         isl_ctx *ctx;
 709
 710         if (!ls)
 711                 return NULL;
 712         if (n == 0 && !isl_local_space_is_named_or_nested(ls, type))
 713                 return ls;
 714
 715         ctx = isl_local_space_get_ctx(ls);
 716         if (first + n > isl_local_space_dim(ls, type))
 717                 isl_die(ctx, isl_error_invalid, "range out of bounds",
 718                         return isl_local_space_free(ls));
 719
 720         ls = isl_local_space_cow(ls);
 721         if (!ls)
 722                 return NULL;
 723
 724         if (type == isl_dim_div) {
 725                 ls->div = isl_mat_drop_rows(ls->div, first, n);
 726         } else {
 727                 ls->dim = isl_space_drop_dims(ls->dim, type, first, n);
 728                 if (!ls->dim)
 729                         return isl_local_space_free(ls);
 730         }
 731
 732         first += 1 + isl_local_space_offset(ls, type);
 733         ls->div = isl_mat_drop_cols(ls->div, first, n);
 734         if (!ls->div)
 735                 return isl_local_space_free(ls);
 736
 737         return ls;
 738 }
 739
 740 __isl_give isl_local_space *isl_local_space_insert_dims(
 741         __isl_take isl_local_space *ls,
 742         enum isl_dim_type type, unsigned first, unsigned n)
 743 {
 744         isl_ctx *ctx;
 745
 746         if (!ls)
 747                 return NULL;
 748         if (n == 0 && !isl_local_space_is_named_or_nested(ls, type))
 749                 return ls;
 750
 751         ctx = isl_local_space_get_ctx(ls);
 752         if (first > isl_local_space_dim(ls, type))
 753                 isl_die(ctx, isl_error_invalid, "position out of bounds",
 754                         return isl_local_space_free(ls));
 755
 756         ls = isl_local_space_cow(ls);
 757         if (!ls)
 758                 return NULL;
 759
 760         if (type == isl_dim_div) {
 761                 ls->div = isl_mat_insert_zero_rows(ls->div, first, n);
 762         } else {
 763                 ls->dim = isl_space_insert_dims(ls->dim, type, first, n);
 764                 if (!ls->dim)
 765                         return isl_local_space_free(ls);
 766         }
 767
 768         first += 1 + isl_local_space_offset(ls, type);
 769         ls->div = isl_mat_insert_zero_cols(ls->div, first, n);
 770         if (!ls->div)
 771                 return isl_local_space_free(ls);
 772
 773         return ls;
 774 }
 775
 776 /* Check if the constraints pointed to by "constraint" is a div
 777  * constraint corresponding to div "div" in "ls".
 778  *
 779  * That is, if div = floor(f/m), then check if the constraint is
 780  *
 781  *              f - m d >= 0
 782  * or
 783  *              -(f-(m-1)) + m d >= 0
 784  */
 785 int isl_local_space_is_div_constraint(__isl_keep isl_local_space *ls,
 786         isl_int *constraint, unsigned div)
 787 {
 788         unsigned pos;
 789
 790         if (!ls)
 791                 return -1;
 792
 793         if (isl_int_is_zero(ls->div->row[div][0]))
 794                 return 0;
 795
 796         pos = isl_local_space_offset(ls, isl_dim_div) + div;
 797
 798         if (isl_int_eq(constraint[pos], ls->div->row[div][0])) {
 799                 int neg;
 800                 isl_int_sub(ls->div->row[div][1],
 801                                 ls->div->row[div][1], ls->div->row[div][0]);
 802                 isl_int_add_ui(ls->div->row[div][1], ls->div->row[div][1], 1);
 803                 neg = isl_seq_is_neg(constraint, ls->div->row[div]+1, pos);
 804                 isl_int_sub_ui(ls->div->row[div][1], ls->div->row[div][1], 1);
 805                 isl_int_add(ls->div->row[div][1],
 806                                 ls->div->row[div][1], ls->div->row[div][0]);
 807                 if (!neg)
 808                         return 0;
 809                 if (isl_seq_first_non_zero(constraint+pos+1,
 810                                             ls->div->n_row-div-1) != -1)
 811                         return 0;
 812         } else if (isl_int_abs_eq(constraint[pos], ls->div->row[div][0])) {
 813                 if (!isl_seq_eq(constraint, ls->div->row[div]+1, pos))
 814                         return 0;
 815                 if (isl_seq_first_non_zero(constraint+pos+1,
 816                                             ls->div->n_row-div-1) != -1)
 817                         return 0;
 818         } else
 819                 return 0;
 820
 821         return 1;
 822 }
 823
 824 /*
 825  * Set active[i] to 1 if the dimension at position i is involved
 826  * in the linear expression l.
 827  */
 828 int *isl_local_space_get_active(__isl_keep isl_local_space *ls, isl_int *l)
 829 {
 830         int i, j;
 831         isl_ctx *ctx;
 832         int *active = NULL;
 833         unsigned total;
 834         unsigned offset;
 835
 836         ctx = isl_local_space_get_ctx(ls);
 837         total = isl_local_space_dim(ls, isl_dim_all);
 838         active = isl_calloc_array(ctx, int, total);
 839         if (!active)
 840                 return NULL;
 841
 842         for (i = 0; i < total; ++i)
 843                 active[i] = !isl_int_is_zero(l[i]);
 844
 845         offset = isl_local_space_offset(ls, isl_dim_div) - 1;
 846         for (i = ls->div->n_row - 1; i >= 0; --i) {
 847                 if (!active[offset + i])
 848                         continue;
 849                 for (j = 0; j < total; ++j)
 850                         active[j] |= !isl_int_is_zero(ls->div->row[i][2 + j]);
 851         }
 852
 853         return active;
 854 }
 855
 856 /* Given a local space "ls" of a set, create a local space
 857  * for the lift of the set.  In particular, the result
 858  * is of the form [dim -> local[..]], with ls->div->n_row variables in the
 859  * range of the wrapped map.
 860  */
 861 __isl_give isl_local_space *isl_local_space_lift(
 862         __isl_take isl_local_space *ls)
 863 {
 864         ls = isl_local_space_cow(ls);
 865         if (!ls)
 866                 return NULL;
 867
 868         ls->dim = isl_space_lift(ls->dim, ls->div->n_row);
 869         ls->div = isl_mat_drop_rows(ls->div, 0, ls->div->n_row);
 870         if (!ls->dim || !ls->div)
 871                 return isl_local_space_free(ls);
 872
 873         return ls;
 874 }
 875
 876 /* Construct a basic map that maps a set living in local space "ls"
 877  * to the corresponding lifted local space.
 878  */
 879 __isl_give isl_basic_map *isl_local_space_lifting(
 880         __isl_take isl_local_space *ls)
 881 {
 882         isl_basic_map *lifting;
 883         isl_basic_set *bset;
 884
 885         if (!ls)
 886                 return NULL;
 887         if (!isl_local_space_is_set(ls))
 888                 isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
 889                         "lifting only defined on set spaces",
 890                         return isl_local_space_free(ls));
 891
 892         bset = isl_basic_set_from_local_space(ls);
 893         lifting = isl_basic_set_unwrap(isl_basic_set_lift(bset));
 894         lifting = isl_basic_map_domain_map(lifting);
 895         lifting = isl_basic_map_reverse(lifting);
 896
 897         return lifting;
 898 }