gcc/graphite-sese-to-poly.c

   1 /* Conversion of SESE regions to Polyhedra.
   2    Copyright (C) 2009-2017 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <sebastian.pop@amd.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #define USES_ISL
  22
  23 #include "config.h"
  24
  25 #ifdef HAVE_isl
  26
  27 #include "system.h"
  28 #include "coretypes.h"
  29 #include "backend.h"
  30 #include "cfghooks.h"
  31 #include "tree.h"
  32 #include "gimple.h"
  33 #include "ssa.h"
  34 #include "params.h"
  35 #include "fold-const.h"
  36 #include "gimple-iterator.h"
  37 #include "gimplify.h"
  38 #include "gimplify-me.h"
  39 #include "tree-cfg.h"
  40 #include "tree-ssa-loop-manip.h"
  41 #include "tree-ssa-loop-niter.h"
  42 #include "tree-ssa-loop.h"
  43 #include "tree-into-ssa.h"
  44 #include "tree-pass.h"
  45 #include "cfgloop.h"
  46 #include "tree-data-ref.h"
  47 #include "tree-scalar-evolution.h"
  48 #include "domwalk.h"
  49 #include "tree-ssa-propagate.h"
  50
  51 #include <isl/constraint.h>
  52 #include <isl/set.h>
  53 #include <isl/map.h>
  54 #include <isl/union_map.h>
  55 #include <isl/constraint.h>
  56 #include <isl/aff.h>
  57 #include <isl/val.h>
  58
  59 #include "graphite.h"
  60
  61 /* Assigns to RES the value of the INTEGER_CST T.  */
  62
  63 static inline void
  64 tree_int_to_gmp (tree t, mpz_t res)
  65 {
  66   wi::to_mpz (wi::to_wide (t), res, TYPE_SIGN (TREE_TYPE (t)));
  67 }
  68
  69 /* Return an isl identifier for the polyhedral basic block PBB.  */
  70
  71 static isl_id *
  72 isl_id_for_pbb (scop_p s, poly_bb_p pbb)
  73 {
  74   char name[14];
  75   snprintf (name, sizeof (name), "S_%d", pbb_index (pbb));
  76   return isl_id_alloc (s->isl_context, name, pbb);
  77 }
  78
  79 static isl_pw_aff *extract_affine (scop_p, tree, __isl_take isl_space *space);
  80
  81 /* Extract an affine expression from the chain of recurrence E.  */
  82
  83 static isl_pw_aff *
  84 extract_affine_chrec (scop_p s, tree e, __isl_take isl_space *space)
  85 {
  86   isl_pw_aff *lhs = extract_affine (s, CHREC_LEFT (e), isl_space_copy (space));
  87   isl_pw_aff *rhs = extract_affine (s, CHREC_RIGHT (e), isl_space_copy (space));
  88   isl_local_space *ls = isl_local_space_from_space (space);
  89   unsigned pos = sese_loop_depth (s->scop_info->region, get_chrec_loop (e)) - 1;
  90   isl_aff *loop = isl_aff_set_coefficient_si
  91     (isl_aff_zero_on_domain (ls), isl_dim_in, pos, 1);
  92   isl_pw_aff *l = isl_pw_aff_from_aff (loop);
  93
  94   /* Before multiplying, make sure that the result is affine.  */
  95   gcc_assert (isl_pw_aff_is_cst (rhs)
  96               || isl_pw_aff_is_cst (l));
  97
  98   return isl_pw_aff_add (lhs, isl_pw_aff_mul (rhs, l));
  99 }
 100
 101 /* Extract an affine expression from the mult_expr E.  */
 102
 103 static isl_pw_aff *
 104 extract_affine_mul (scop_p s, tree e, __isl_take isl_space *space)
 105 {
 106   isl_pw_aff *lhs = extract_affine (s, TREE_OPERAND (e, 0),
 107                                     isl_space_copy (space));
 108   isl_pw_aff *rhs = extract_affine (s, TREE_OPERAND (e, 1), space);
 109
 110   if (!isl_pw_aff_is_cst (lhs)
 111       && !isl_pw_aff_is_cst (rhs))
 112     {
 113       isl_pw_aff_free (lhs);
 114       isl_pw_aff_free (rhs);
 115       return NULL;
 116     }
 117
 118   return isl_pw_aff_mul (lhs, rhs);
 119 }
 120
 121 /* Return an isl identifier from the name of the ssa_name E.  */
 122
 123 static isl_id *
 124 isl_id_for_ssa_name (scop_p s, tree e)
 125 {
 126   char name1[14];
 127   snprintf (name1, sizeof (name1), "P_%d", SSA_NAME_VERSION (e));
 128   return isl_id_alloc (s->isl_context, name1, e);
 129 }
 130
 131 /* Return an isl identifier for the data reference DR.  Data references and
 132    scalar references get the same isl_id.  They need to be comparable and are
 133    distinguished through the first dimension, which contains the alias set or
 134    SSA_NAME_VERSION number.  */
 135
 136 static isl_id *
 137 isl_id_for_dr (scop_p s)
 138 {
 139   return isl_id_alloc (s->isl_context, "", 0);
 140 }
 141
 142 /* Extract an affine expression from the ssa_name E.  */
 143
 144 static isl_pw_aff *
 145 extract_affine_name (int dimension, __isl_take isl_space *space)
 146 {
 147   isl_set *dom = isl_set_universe (isl_space_copy (space));
 148   isl_aff *aff = isl_aff_zero_on_domain (isl_local_space_from_space (space));
 149   aff = isl_aff_add_coefficient_si (aff, isl_dim_param, dimension, 1);
 150   return isl_pw_aff_alloc (dom, aff);
 151 }
 152
 153 /* Convert WI to a isl_val with CTX.  */
 154
 155 static __isl_give isl_val *
 156 isl_val_int_from_wi (isl_ctx *ctx, const widest_int &wi)
 157 {
 158   if (wi::neg_p (wi, SIGNED))
 159     {
 160       widest_int mwi = -wi;
 161       return isl_val_neg (isl_val_int_from_chunks (ctx, mwi.get_len (),
 162                                                    sizeof (HOST_WIDE_INT),
 163                                                    mwi.get_val ()));
 164     }
 165   return isl_val_int_from_chunks (ctx, wi.get_len (), sizeof (HOST_WIDE_INT),
 166                                   wi.get_val ());
 167 }
 168
 169 /* Extract an affine expression from the gmp constant G.  */
 170
 171 static isl_pw_aff *
 172 extract_affine_wi (const widest_int &g, __isl_take isl_space *space)
 173 {
 174   isl_local_space *ls = isl_local_space_from_space (isl_space_copy (space));
 175   isl_aff *aff = isl_aff_zero_on_domain (ls);
 176   isl_set *dom = isl_set_universe (space);
 177   isl_ctx *ct = isl_aff_get_ctx (aff);
 178   isl_val *v = isl_val_int_from_wi (ct, g);
 179   aff = isl_aff_add_constant_val (aff, v);
 180
 181   return isl_pw_aff_alloc (dom, aff);
 182 }
 183
 184 /* Extract an affine expression from the integer_cst E.  */
 185
 186 static isl_pw_aff *
 187 extract_affine_int (tree e, __isl_take isl_space *space)
 188 {
 189   isl_pw_aff *res = extract_affine_wi (wi::to_widest (e), space);
 190   return res;
 191 }
 192
 193 /* Compute pwaff mod 2^width.  */
 194
 195 static isl_pw_aff *
 196 wrap (isl_pw_aff *pwaff, unsigned width)
 197 {
 198   isl_val *mod;
 199
 200   mod = isl_val_int_from_ui (isl_pw_aff_get_ctx (pwaff), width);
 201   mod = isl_val_2exp (mod);
 202   pwaff = isl_pw_aff_mod_val (pwaff, mod);
 203
 204   return pwaff;
 205 }
 206
 207 /* When parameter NAME is in REGION, returns its index in SESE_PARAMS.
 208    Otherwise returns -1.  */
 209
 210 static inline int
 211 parameter_index_in_region (tree name, sese_info_p region)
 212 {
 213   int i;
 214   tree p;
 215   FOR_EACH_VEC_ELT (region->params, i, p)
 216     if (p == name)
 217       return i;
 218   return -1;
 219 }
 220
 221 /* Extract an affine expression from the tree E in the scop S.  */
 222
 223 static isl_pw_aff *
 224 extract_affine (scop_p s, tree e, __isl_take isl_space *space)
 225 {
 226   isl_pw_aff *lhs, *rhs, *res;
 227
 228   if (e == chrec_dont_know) {
 229     isl_space_free (space);
 230     return NULL;
 231   }
 232
 233   tree type = TREE_TYPE (e);
 234   switch (TREE_CODE (e))
 235     {
 236     case POLYNOMIAL_CHREC:
 237       res = extract_affine_chrec (s, e, space);
 238       break;
 239
 240     case MULT_EXPR:
 241       res = extract_affine_mul (s, e, space);
 242       break;
 243
 244     case POINTER_PLUS_EXPR:
 245       {
 246         lhs = extract_affine (s, TREE_OPERAND (e, 0), isl_space_copy (space));
 247         /* The RHS of a pointer-plus expression is to be interpreted
 248            as signed value.  Try to look through a sign-changing conversion
 249            first.  */
 250         tree tem = TREE_OPERAND (e, 1);
 251         STRIP_NOPS (tem);
 252         rhs = extract_affine (s, tem, space);
 253         if (TYPE_UNSIGNED (TREE_TYPE (tem)))
 254           rhs = wrap (rhs, TYPE_PRECISION (type) - 1);
 255         res = isl_pw_aff_add (lhs, rhs);
 256         break;
 257       }
 258
 259     case PLUS_EXPR:
 260       lhs = extract_affine (s, TREE_OPERAND (e, 0), isl_space_copy (space));
 261       rhs = extract_affine (s, TREE_OPERAND (e, 1), space);
 262       res = isl_pw_aff_add (lhs, rhs);
 263       break;
 264
 265     case MINUS_EXPR:
 266       lhs = extract_affine (s, TREE_OPERAND (e, 0), isl_space_copy (space));
 267       rhs = extract_affine (s, TREE_OPERAND (e, 1), space);
 268       res = isl_pw_aff_sub (lhs, rhs);
 269       break;
 270
 271     case BIT_NOT_EXPR:
 272       lhs = extract_affine (s, integer_minus_one_node, isl_space_copy (space));
 273       rhs = extract_affine (s, TREE_OPERAND (e, 0), space);
 274       res = isl_pw_aff_sub (lhs, rhs);
 275       break;
 276
 277     case NEGATE_EXPR:
 278       lhs = extract_affine (s, TREE_OPERAND (e, 0), isl_space_copy (space));
 279       rhs = extract_affine (s, integer_minus_one_node, space);
 280       res = isl_pw_aff_mul (lhs, rhs);
 281       break;
 282
 283     case SSA_NAME:
 284       {
 285         gcc_assert (! defined_in_sese_p (e, s->scop_info->region));
 286         int dim = parameter_index_in_region (e, s->scop_info);
 287         gcc_assert (dim != -1);
 288         res = extract_affine_name (dim, space);
 289         break;
 290       }
 291
 292     case INTEGER_CST:
 293       res = extract_affine_int (e, space);
 294       /* No need to wrap a single integer.  */
 295       return res;
 296
 297     CASE_CONVERT:
 298       {
 299         tree itype = TREE_TYPE (TREE_OPERAND (e, 0));
 300         res = extract_affine (s, TREE_OPERAND (e, 0), space);
 301         /* Signed values, even if overflow is undefined, get modulo-reduced.
 302            But only if not all values of the old type fit in the new.  */
 303         if (! TYPE_UNSIGNED (type)
 304             && ((TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (e, 0)))
 305                  && TYPE_PRECISION (type) <= TYPE_PRECISION (itype))
 306                 || TYPE_PRECISION (type) < TYPE_PRECISION (itype)))
 307           res = wrap (res, TYPE_PRECISION (type) - 1);
 308         break;
 309       }
 310
 311     case NON_LVALUE_EXPR:
 312       res = extract_affine (s, TREE_OPERAND (e, 0), space);
 313       break;
 314
 315     default:
 316       gcc_unreachable ();
 317       break;
 318     }
 319
 320   if (TYPE_UNSIGNED (type))
 321     res = wrap (res, TYPE_PRECISION (type));
 322
 323   return res;
 324 }
 325
 326 /* Returns a linear expression for tree T evaluated in PBB.  */
 327
 328 static isl_pw_aff *
 329 create_pw_aff_from_tree (poly_bb_p pbb, loop_p loop, tree t)
 330 {
 331   scop_p scop = PBB_SCOP (pbb);
 332
 333   t = scalar_evolution_in_region (scop->scop_info->region, loop, t);
 334
 335   gcc_assert (!chrec_contains_undetermined (t));
 336   gcc_assert (!automatically_generated_chrec_p (t));
 337
 338   return extract_affine (scop, t, isl_set_get_space (pbb->domain));
 339 }
 340
 341 /* Add conditional statement STMT to pbb.  CODE is used as the comparison
 342    operator.  This allows us to invert the condition or to handle
 343    inequalities.  */
 344
 345 static void
 346 add_condition_to_pbb (poly_bb_p pbb, gcond *stmt, enum tree_code code)
 347 {
 348   loop_p loop = gimple_bb (stmt)->loop_father;
 349   isl_pw_aff *lhs = create_pw_aff_from_tree (pbb, loop, gimple_cond_lhs (stmt));
 350   isl_pw_aff *rhs = create_pw_aff_from_tree (pbb, loop, gimple_cond_rhs (stmt));
 351
 352   isl_set *cond;
 353   switch (code)
 354     {
 355       case LT_EXPR:
 356         cond = isl_pw_aff_lt_set (lhs, rhs);
 357         break;
 358
 359       case GT_EXPR:
 360         cond = isl_pw_aff_gt_set (lhs, rhs);
 361         break;
 362
 363       case LE_EXPR:
 364         cond = isl_pw_aff_le_set (lhs, rhs);
 365         break;
 366
 367       case GE_EXPR:
 368         cond = isl_pw_aff_ge_set (lhs, rhs);
 369         break;
 370
 371       case EQ_EXPR:
 372         cond = isl_pw_aff_eq_set (lhs, rhs);
 373         break;
 374
 375       case NE_EXPR:
 376         cond = isl_pw_aff_ne_set (lhs, rhs);
 377         break;
 378
 379       default:
 380         gcc_unreachable ();
 381     }
 382
 383   cond = isl_set_coalesce (cond);
 384   cond = isl_set_set_tuple_id (cond, isl_set_get_tuple_id (pbb->domain));
 385   pbb->domain = isl_set_coalesce (isl_set_intersect (pbb->domain, cond));
 386 }
 387
 388 /* Add conditions to the domain of PBB.  */
 389
 390 static void
 391 add_conditions_to_domain (poly_bb_p pbb)
 392 {
 393   unsigned int i;
 394   gimple *stmt;
 395   gimple_poly_bb_p gbb = PBB_BLACK_BOX (pbb);
 396
 397   if (GBB_CONDITIONS (gbb).is_empty ())
 398     return;
 399
 400   FOR_EACH_VEC_ELT (GBB_CONDITIONS (gbb), i, stmt)
 401     switch (gimple_code (stmt))
 402       {
 403       case GIMPLE_COND:
 404           {
 405             /* Don't constrain on anything else than INTEGER_TYPE.  */
 406             if (TREE_CODE (TREE_TYPE (gimple_cond_lhs (stmt))) != INTEGER_TYPE)
 407               break;
 408
 409             gcond *cond_stmt = as_a <gcond *> (stmt);
 410             enum tree_code code = gimple_cond_code (cond_stmt);
 411
 412             /* The conditions for ELSE-branches are inverted.  */
 413             if (!GBB_CONDITION_CASES (gbb)[i])
 414               code = invert_tree_comparison (code, false);
 415
 416             add_condition_to_pbb (pbb, cond_stmt, code);
 417             break;
 418           }
 419
 420       default:
 421         gcc_unreachable ();
 422         break;
 423       }
 424 }
 425
 426 /* Add constraints on the possible values of parameter P from the type
 427    of P.  */
 428
 429 static void
 430 add_param_constraints (scop_p scop, graphite_dim_t p, tree parameter)
 431 {
 432   tree type = TREE_TYPE (parameter);
 433   wide_int min, max;
 434
 435   gcc_assert (INTEGRAL_TYPE_P (type) || POINTER_TYPE_P (type));
 436
 437   if (INTEGRAL_TYPE_P (type)
 438       && get_range_info (parameter, &min, &max) == VR_RANGE)
 439     ;
 440   else
 441     {
 442       min = wi::min_value (TYPE_PRECISION (type), TYPE_SIGN (type));
 443       max = wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type));
 444     }
 445
 446   isl_space *space = isl_set_get_space (scop->param_context);
 447   isl_constraint *c = isl_inequality_alloc (isl_local_space_from_space (space));
 448   isl_val *v = isl_val_int_from_wi (scop->isl_context,
 449                                     widest_int::from (min, TYPE_SIGN (type)));
 450   v = isl_val_neg (v);
 451   c = isl_constraint_set_constant_val (c, v);
 452   c = isl_constraint_set_coefficient_si (c, isl_dim_param, p, 1);
 453   scop->param_context = isl_set_coalesce
 454       (isl_set_add_constraint (scop->param_context, c));
 455
 456   space = isl_set_get_space (scop->param_context);
 457   c = isl_inequality_alloc (isl_local_space_from_space (space));
 458   v = isl_val_int_from_wi (scop->isl_context,
 459                            widest_int::from (max, TYPE_SIGN (type)));
 460   c = isl_constraint_set_constant_val (c, v);
 461   c = isl_constraint_set_coefficient_si (c, isl_dim_param, p, -1);
 462   scop->param_context = isl_set_coalesce
 463       (isl_set_add_constraint (scop->param_context, c));
 464 }
 465
 466 /* Add a constrain to the ACCESSES polyhedron for the alias set of
 467    data reference DR.  ACCESSP_NB_DIMS is the dimension of the
 468    ACCESSES polyhedron, DOM_NB_DIMS is the dimension of the iteration
 469    domain.  */
 470
 471 static isl_map *
 472 pdr_add_alias_set (isl_map *acc, dr_info &dri)
 473 {
 474   isl_constraint *c = isl_equality_alloc
 475       (isl_local_space_from_space (isl_map_get_space (acc)));
 476   /* Positive numbers for all alias sets.  */
 477   c = isl_constraint_set_constant_si (c, -dri.alias_set);
 478   c = isl_constraint_set_coefficient_si (c, isl_dim_out, 0, 1);
 479
 480   return isl_map_add_constraint (acc, c);
 481 }
 482
 483 /* Assign the affine expression INDEX to the output dimension POS of
 484    MAP and return the result.  */
 485
 486 static isl_map *
 487 set_index (isl_map *map, int pos, isl_pw_aff *index)
 488 {
 489   isl_map *index_map;
 490   int len = isl_map_dim (map, isl_dim_out);
 491   isl_id *id;
 492
 493   index_map = isl_map_from_pw_aff (index);
 494   index_map = isl_map_insert_dims (index_map, isl_dim_out, 0, pos);
 495   index_map = isl_map_add_dims (index_map, isl_dim_out, len - pos - 1);
 496
 497   id = isl_map_get_tuple_id (map, isl_dim_out);
 498   index_map = isl_map_set_tuple_id (index_map, isl_dim_out, id);
 499   id = isl_map_get_tuple_id (map, isl_dim_in);
 500   index_map = isl_map_set_tuple_id (index_map, isl_dim_in, id);
 501
 502   return isl_map_intersect (map, index_map);
 503 }
 504
 505 /* Add to ACCESSES polyhedron equalities defining the access functions
 506    to the memory.  ACCESSP_NB_DIMS is the dimension of the ACCESSES
 507    polyhedron, DOM_NB_DIMS is the dimension of the iteration domain.
 508    PBB is the poly_bb_p that contains the data reference DR.  */
 509
 510 static isl_map *
 511 pdr_add_memory_accesses (isl_map *acc, dr_info &dri)
 512 {
 513   data_reference_p dr = dri.dr;
 514   poly_bb_p pbb = dri.pbb;
 515   int i, nb_subscripts = DR_NUM_DIMENSIONS (dr);
 516   scop_p scop = PBB_SCOP (pbb);
 517
 518   for (i = 0; i < nb_subscripts; i++)
 519     {
 520       isl_pw_aff *aff;
 521       tree afn = DR_ACCESS_FN (dr, i);
 522
 523       aff = extract_affine (scop, afn,
 524                             isl_space_domain (isl_map_get_space (acc)));
 525       acc = set_index (acc, nb_subscripts - i , aff);
 526     }
 527
 528   return isl_map_coalesce (acc);
 529 }
 530
 531 /* Return true when the LOW and HIGH bounds of an array reference REF are valid
 532    to extract constraints on accessed elements of the array.  Returning false is
 533    the conservative answer.  */
 534
 535 static bool
 536 bounds_are_valid (tree ref, tree low, tree high)
 537 {
 538   if (!high)
 539     return false;
 540
 541   if (!tree_fits_shwi_p (low)
 542       || !tree_fits_shwi_p (high))
 543     return false;
 544
 545   /* 1-element arrays at end of structures may extend over
 546      their declared size.  */
 547   if (array_at_struct_end_p (ref)
 548       && operand_equal_p (low, high, 0))
 549     return false;
 550
 551   /* Fortran has some arrays where high bound is -1 and low is 0.  */
 552   if (integer_onep (fold_build2 (LT_EXPR, boolean_type_node, high, low)))
 553     return false;
 554
 555   return true;
 556 }
 557
 558 /* Add constrains representing the size of the accessed data to the
 559    ACCESSES polyhedron.  ACCESSP_NB_DIMS is the dimension of the
 560    ACCESSES polyhedron, DOM_NB_DIMS is the dimension of the iteration
 561    domain.  */
 562
 563 static isl_set *
 564 pdr_add_data_dimensions (isl_set *subscript_sizes, scop_p scop,
 565                          data_reference_p dr)
 566 {
 567   tree ref = DR_REF (dr);
 568
 569   int nb_subscripts = DR_NUM_DIMENSIONS (dr);
 570   for (int i = nb_subscripts - 1; i >= 0; i--, ref = TREE_OPERAND (ref, 0))
 571     {
 572       if (TREE_CODE (ref) != ARRAY_REF)
 573         return subscript_sizes;
 574
 575       tree low = array_ref_low_bound (ref);
 576       tree high = array_ref_up_bound (ref);
 577
 578       if (!bounds_are_valid (ref, low, high))
 579         continue;
 580
 581       isl_space *space = isl_set_get_space (subscript_sizes);
 582       isl_pw_aff *lb = extract_affine_int (low, isl_space_copy (space));
 583       isl_pw_aff *ub = extract_affine_int (high, isl_space_copy (space));
 584
 585       /* high >= 0 */
 586       isl_set *valid = isl_pw_aff_nonneg_set (isl_pw_aff_copy (ub));
 587       valid = isl_set_project_out (valid, isl_dim_set, 0,
 588                                    isl_set_dim (valid, isl_dim_set));
 589       scop->param_context = isl_set_coalesce
 590         (isl_set_intersect (scop->param_context, valid));
 591
 592       isl_aff *aff
 593         = isl_aff_zero_on_domain (isl_local_space_from_space (space));
 594       aff = isl_aff_add_coefficient_si (aff, isl_dim_in, i + 1, 1);
 595       isl_set *univ
 596         = isl_set_universe (isl_space_domain (isl_aff_get_space (aff)));
 597       isl_pw_aff *index = isl_pw_aff_alloc (univ, aff);
 598
 599       isl_id *id = isl_set_get_tuple_id (subscript_sizes);
 600       lb = isl_pw_aff_set_tuple_id (lb, isl_dim_in, isl_id_copy (id));
 601       ub = isl_pw_aff_set_tuple_id (ub, isl_dim_in, id);
 602
 603       /* low <= sub_i <= high */
 604       isl_set *lbs = isl_pw_aff_ge_set (isl_pw_aff_copy (index), lb);
 605       isl_set *ubs = isl_pw_aff_le_set (index, ub);
 606       subscript_sizes = isl_set_intersect (subscript_sizes, lbs);
 607       subscript_sizes = isl_set_intersect (subscript_sizes, ubs);
 608     }
 609
 610   return isl_set_coalesce (subscript_sizes);
 611 }
 612
 613 /* Build data accesses for DRI.  */
 614
 615 static void
 616 build_poly_dr (dr_info &dri)
 617 {
 618   isl_map *acc;
 619   isl_set *subscript_sizes;
 620   poly_bb_p pbb = dri.pbb;
 621   data_reference_p dr = dri.dr;
 622   scop_p scop = PBB_SCOP (pbb);
 623   isl_id *id = isl_id_for_dr (scop);
 624
 625   {
 626     isl_space *dc = isl_set_get_space (pbb->domain);
 627     int nb_out = 1 + DR_NUM_DIMENSIONS (dr);
 628     isl_space *space = isl_space_add_dims (isl_space_from_domain (dc),
 629                                            isl_dim_out, nb_out);
 630
 631     acc = isl_map_universe (space);
 632     acc = isl_map_set_tuple_id (acc, isl_dim_out, isl_id_copy (id));
 633   }
 634
 635   acc = pdr_add_alias_set (acc, dri);
 636   acc = pdr_add_memory_accesses (acc, dri);
 637
 638   {
 639     int nb = 1 + DR_NUM_DIMENSIONS (dr);
 640     isl_space *space = isl_space_set_alloc (scop->isl_context, 0, nb);
 641
 642     space = isl_space_set_tuple_id (space, isl_dim_set, id);
 643     subscript_sizes = isl_set_nat_universe (space);
 644     subscript_sizes = isl_set_fix_si (subscript_sizes, isl_dim_set, 0,
 645                                       dri.alias_set);
 646     subscript_sizes = pdr_add_data_dimensions (subscript_sizes, scop, dr);
 647   }
 648
 649   new_poly_dr (pbb, DR_STMT (dr), DR_IS_READ (dr) ? PDR_READ : PDR_WRITE,
 650                acc, subscript_sizes);
 651 }
 652
 653 static void
 654 build_poly_sr_1 (poly_bb_p pbb, gimple *stmt, tree var, enum poly_dr_type kind,
 655                  isl_map *acc, isl_set *subscript_sizes)
 656 {
 657   scop_p scop = PBB_SCOP (pbb);
 658   /* Each scalar variables has a unique alias set number starting from
 659      the maximum alias set assigned to a dr.  */
 660   int alias_set = scop->max_alias_set + SSA_NAME_VERSION (var);
 661   subscript_sizes = isl_set_fix_si (subscript_sizes, isl_dim_set, 0,
 662                                     alias_set);
 663
 664   /* Add a constrain to the ACCESSES polyhedron for the alias set of
 665      data reference DR.  */
 666   isl_constraint *c
 667     = isl_equality_alloc (isl_local_space_from_space (isl_map_get_space (acc)));
 668   c = isl_constraint_set_constant_si (c, -alias_set);
 669   c = isl_constraint_set_coefficient_si (c, isl_dim_out, 0, 1);
 670
 671   new_poly_dr (pbb, stmt, kind, isl_map_add_constraint (acc, c),
 672                subscript_sizes);
 673 }
 674
 675 /* Record all cross basic block scalar variables in PBB.  */
 676
 677 static void
 678 build_poly_sr (poly_bb_p pbb)
 679 {
 680   scop_p scop = PBB_SCOP (pbb);
 681   gimple_poly_bb_p gbb = PBB_BLACK_BOX (pbb);
 682   vec<scalar_use> &reads = gbb->read_scalar_refs;
 683   vec<tree> &writes = gbb->write_scalar_refs;
 684
 685   isl_space *dc = isl_set_get_space (pbb->domain);
 686   int nb_out = 1;
 687   isl_space *space = isl_space_add_dims (isl_space_from_domain (dc),
 688                                          isl_dim_out, nb_out);
 689   isl_id *id = isl_id_for_dr (scop);
 690   space = isl_space_set_tuple_id (space, isl_dim_set, isl_id_copy (id));
 691   isl_map *acc = isl_map_universe (isl_space_copy (space));
 692   acc = isl_map_set_tuple_id (acc, isl_dim_out, id);
 693   isl_set *subscript_sizes = isl_set_nat_universe (space);
 694
 695   int i;
 696   tree var;
 697   FOR_EACH_VEC_ELT (writes, i, var)
 698     build_poly_sr_1 (pbb, SSA_NAME_DEF_STMT (var), var, PDR_WRITE,
 699                      isl_map_copy (acc), isl_set_copy (subscript_sizes));
 700
 701   scalar_use *use;
 702   FOR_EACH_VEC_ELT (reads, i, use)
 703     build_poly_sr_1 (pbb, use->first, use->second, PDR_READ, isl_map_copy (acc),
 704                      isl_set_copy (subscript_sizes));
 705
 706   isl_map_free (acc);
 707   isl_set_free (subscript_sizes);
 708 }
 709
 710 /* Build data references in SCOP.  */
 711
 712 static void
 713 build_scop_drs (scop_p scop)
 714 {
 715   int i;
 716   dr_info *dri;
 717   FOR_EACH_VEC_ELT (scop->drs, i, dri)
 718     build_poly_dr (*dri);
 719
 720   poly_bb_p pbb;
 721   FOR_EACH_VEC_ELT (scop->pbbs, i, pbb)
 722     build_poly_sr (pbb);
 723 }
 724
 725 /* Add to the iteration DOMAIN one extra dimension for LOOP->num.  */
 726
 727 static isl_set *
 728 add_iter_domain_dimension (__isl_take isl_set *domain, loop_p loop, scop_p scop)
 729 {
 730   int loop_index = isl_set_dim (domain, isl_dim_set);
 731   domain = isl_set_add_dims (domain, isl_dim_set, 1);
 732   char name[50];
 733   snprintf (name, sizeof(name), "i%d", loop->num);
 734   isl_id *label = isl_id_alloc (scop->isl_context, name, NULL);
 735   return isl_set_set_dim_id (domain, isl_dim_set, loop_index, label);
 736 }
 737
 738 /* Add constraints to DOMAIN for each loop from LOOP up to CONTEXT.  */
 739
 740 static isl_set *
 741 add_loop_constraints (scop_p scop, __isl_take isl_set *domain, loop_p loop,
 742                       loop_p context)
 743 {
 744   if (loop == context)
 745     return domain;
 746   const sese_l &region = scop->scop_info->region;
 747   if (!loop_in_sese_p (loop, region))
 748     return domain;
 749
 750   /* Recursion all the way up to the context loop.  */
 751   domain = add_loop_constraints (scop, domain, loop_outer (loop), context);
 752
 753   /* Then, build constraints over the loop in post-order: outer to inner.  */
 754
 755   int loop_index = isl_set_dim (domain, isl_dim_set);
 756   if (dump_file)
 757     fprintf (dump_file, "[sese-to-poly] adding one extra dimension to the "
 758              "domain for loop_%d.\n", loop->num);
 759   domain = add_iter_domain_dimension (domain, loop, scop);
 760   isl_space *space = isl_set_get_space (domain);
 761
 762   /* 0 <= loop_i */
 763   isl_local_space *ls = isl_local_space_from_space (isl_space_copy (space));
 764   isl_constraint *c = isl_inequality_alloc (ls);
 765   c = isl_constraint_set_coefficient_si (c, isl_dim_set, loop_index, 1);
 766   if (dump_file)
 767     {
 768       fprintf (dump_file, "[sese-to-poly] adding constraint to the domain: ");
 769       print_isl_constraint (dump_file, c);
 770     }
 771   domain = isl_set_add_constraint (domain, c);
 772
 773   tree nb_iters = number_of_latch_executions (loop);
 774   if (TREE_CODE (nb_iters) == INTEGER_CST)
 775     {
 776       /* loop_i <= cst_nb_iters */
 777       isl_local_space *ls = isl_local_space_from_space (space);
 778       isl_constraint *c = isl_inequality_alloc (ls);
 779       c = isl_constraint_set_coefficient_si (c, isl_dim_set, loop_index, -1);
 780       isl_val *v
 781         = isl_val_int_from_wi (scop->isl_context, wi::to_widest (nb_iters));
 782       c = isl_constraint_set_constant_val (c, v);
 783       return isl_set_add_constraint (domain, c);
 784     }
 785   /* loop_i <= expr_nb_iters */
 786   gcc_assert (!chrec_contains_undetermined (nb_iters));
 787   nb_iters = scalar_evolution_in_region (region, loop, nb_iters);
 788   gcc_assert (!chrec_contains_undetermined (nb_iters));
 789
 790   isl_pw_aff *aff_nb_iters = extract_affine (scop, nb_iters,
 791                                              isl_space_copy (space));
 792   isl_set *valid = isl_pw_aff_nonneg_set (isl_pw_aff_copy (aff_nb_iters));
 793   valid = isl_set_project_out (valid, isl_dim_set, 0,
 794                                isl_set_dim (valid, isl_dim_set));
 795
 796   if (valid)
 797     scop->param_context = isl_set_intersect (scop->param_context, valid);
 798
 799   ls = isl_local_space_from_space (isl_space_copy (space));
 800   isl_aff *loop_i = isl_aff_set_coefficient_si (isl_aff_zero_on_domain (ls),
 801                                                 isl_dim_in, loop_index, 1);
 802   isl_set *le = isl_pw_aff_le_set (isl_pw_aff_from_aff (loop_i),
 803                                    isl_pw_aff_copy (aff_nb_iters));
 804   if (dump_file)
 805     {
 806       fprintf (dump_file, "[sese-to-poly] adding constraint to the domain: ");
 807       print_isl_set (dump_file, le);
 808     }
 809   domain = isl_set_intersect (domain, le);
 810
 811   widest_int nit;
 812   if (!max_stmt_executions (loop, &nit))
 813     {
 814       isl_pw_aff_free (aff_nb_iters);
 815       isl_space_free (space);
 816       return domain;
 817     }
 818
 819   /* NIT is an upper bound to NB_ITERS: "NIT >= NB_ITERS", although we
 820      do not know whether the loop executes at least once.  */
 821   --nit;
 822
 823   isl_pw_aff *approx = extract_affine_wi (nit, isl_space_copy (space));
 824   isl_set *x = isl_pw_aff_ge_set (approx, aff_nb_iters);
 825   x = isl_set_project_out (x, isl_dim_set, 0,
 826                            isl_set_dim (x, isl_dim_set));
 827   scop->param_context = isl_set_intersect (scop->param_context, x);
 828
 829   ls = isl_local_space_from_space (space);
 830   c = isl_inequality_alloc (ls);
 831   c = isl_constraint_set_coefficient_si (c, isl_dim_set, loop_index, -1);
 832   isl_val *v = isl_val_int_from_wi (scop->isl_context, nit);
 833   c = isl_constraint_set_constant_val (c, v);
 834
 835   if (dump_file)
 836     {
 837       fprintf (dump_file, "[sese-to-poly] adding constraint to the domain: ");
 838       print_isl_constraint (dump_file, c);
 839     }
 840
 841   return isl_set_add_constraint (domain, c);
 842 }
 843
 844 /* Builds the original iteration domains for each pbb in the SCOP.  */
 845
 846 static int
 847 build_iteration_domains (scop_p scop, __isl_keep isl_set *context,
 848                          int index, loop_p context_loop)
 849 {
 850   loop_p current = pbb_loop (scop->pbbs[index]);
 851   isl_set *domain = isl_set_copy (context);
 852   domain = add_loop_constraints (scop, domain, current, context_loop);
 853   const sese_l &region = scop->scop_info->region;
 854
 855   int i;
 856   poly_bb_p pbb;
 857   FOR_EACH_VEC_ELT_FROM (scop->pbbs, i, pbb, index)
 858     {
 859       loop_p loop = pbb_loop (pbb);
 860       if (current == loop)
 861         {
 862           pbb->iterators = isl_set_copy (domain);
 863           pbb->domain = isl_set_copy (domain);
 864           pbb->domain = isl_set_set_tuple_id (pbb->domain,
 865                                               isl_id_for_pbb (scop, pbb));
 866           add_conditions_to_domain (pbb);
 867
 868           if (dump_file)
 869             {
 870               fprintf (dump_file, "[sese-to-poly] set pbb_%d->domain: ",
 871                        pbb_index (pbb));
 872               print_isl_set (dump_file, domain);
 873             }
 874           continue;
 875         }
 876
 877       while (loop_in_sese_p (loop, region)
 878              && current != loop)
 879         loop = loop_outer (loop);
 880
 881       if (current != loop)
 882         {
 883           /* A statement in a different loop nest than CURRENT loop.  */
 884           isl_set_free (domain);
 885           return i;
 886         }
 887
 888       /* A statement nested in the CURRENT loop.  */
 889       i = build_iteration_domains (scop, domain, i, current);
 890       i--;
 891     }
 892
 893   isl_set_free (domain);
 894   return i;
 895 }
 896
 897 /* Assign dimension for each parameter in SCOP and add constraints for the
 898    parameters.  */
 899
 900 static void
 901 build_scop_context (scop_p scop)
 902 {
 903   sese_info_p region = scop->scop_info;
 904   unsigned nbp = sese_nb_params (region);
 905   isl_space *space = isl_space_set_alloc (scop->isl_context, nbp, 0);
 906
 907   unsigned i;
 908   tree e;
 909   FOR_EACH_VEC_ELT (region->params, i, e)
 910     space = isl_space_set_dim_id (space, isl_dim_param, i,
 911                                   isl_id_for_ssa_name (scop, e));
 912
 913   scop->param_context = isl_set_universe (space);
 914
 915   FOR_EACH_VEC_ELT (region->params, i, e)
 916     add_param_constraints (scop, i, e);
 917 }
 918
 919 /* Return true when loop A is nested in loop B.  */
 920
 921 static bool
 922 nested_in (loop_p a, loop_p b)
 923 {
 924   return b == find_common_loop (a, b);
 925 }
 926
 927 /* Return the loop at a specific SCOP->pbbs[*INDEX].  */
 928 static loop_p
 929 loop_at (scop_p scop, int *index)
 930 {
 931   return pbb_loop (scop->pbbs[*index]);
 932 }
 933
 934 /* Return the index of any pbb belonging to loop or a subloop of A.  */
 935
 936 static int
 937 index_outermost_in_loop (loop_p a, scop_p scop)
 938 {
 939   int i, outermost = -1;
 940   int last_depth = -1;
 941   poly_bb_p pbb;
 942   FOR_EACH_VEC_ELT (scop->pbbs, i, pbb)
 943     if (nested_in (pbb_loop (pbb), a)
 944         && (last_depth == -1
 945             || last_depth > (int) loop_depth (pbb_loop (pbb))))
 946       {
 947         outermost = i;
 948         last_depth = loop_depth (pbb_loop (pbb));
 949       }
 950   return outermost;
 951 }
 952
 953 /* Return the index of any pbb belonging to loop or a subloop of A.  */
 954
 955 static int
 956 index_pbb_in_loop (loop_p a, scop_p scop)
 957 {
 958   int i;
 959   poly_bb_p pbb;
 960   FOR_EACH_VEC_ELT (scop->pbbs, i, pbb)
 961     if (pbb_loop (pbb) == a)
 962       return i;
 963   return -1;
 964 }
 965
 966 static poly_bb_p
 967 outermost_pbb_in (loop_p loop, scop_p scop)
 968 {
 969   int x = index_pbb_in_loop (loop, scop);
 970   if (x == -1)
 971     x = index_outermost_in_loop (loop, scop);
 972   return scop->pbbs[x];
 973 }
 974
 975 static isl_schedule *
 976 add_in_sequence (__isl_take isl_schedule *a, __isl_take isl_schedule *b)
 977 {
 978   gcc_assert (a || b);
 979
 980   if (!a)
 981     return b;
 982
 983   if (!b)
 984     return a;
 985
 986   return isl_schedule_sequence (a, b);
 987 }
 988
 989 struct map_to_dimension_data {
 990   int n;
 991   isl_union_pw_multi_aff *res;
 992 };
 993
 994 /* Create a function that maps the elements of SET to its N-th dimension and add
 995    it to USER->res.  */
 996
 997 static isl_stat
 998 add_outer_projection (__isl_take isl_set *set, void *user)
 999 {
1000   struct map_to_dimension_data *data = (struct map_to_dimension_data *) user;
1001   int dim = isl_set_dim (set, isl_dim_set);
1002   isl_space *space = isl_set_get_space (set);
1003
1004   gcc_assert (dim >= data->n);
1005   isl_pw_multi_aff *pma
1006     = isl_pw_multi_aff_project_out_map (space, isl_dim_set, data->n,
1007                                         dim - data->n);
1008   data->res = isl_union_pw_multi_aff_add_pw_multi_aff (data->res, pma);
1009
1010   isl_set_free (set);
1011   return isl_stat_ok;
1012 }
1013
1014 /* Return SET in which all inner dimensions above N are removed.  */
1015
1016 static isl_multi_union_pw_aff *
1017 outer_projection_mupa (__isl_take isl_union_set *set, int n)
1018 {
1019   gcc_assert (n >= 0);
1020   gcc_assert (set);
1021   gcc_assert (!isl_union_set_is_empty (set));
1022
1023   isl_space *space = isl_union_set_get_space (set);
1024   isl_union_pw_multi_aff *pwaff = isl_union_pw_multi_aff_empty (space);
1025
1026   struct map_to_dimension_data data = {n, pwaff};
1027
1028   if (isl_union_set_foreach_set (set, &add_outer_projection, &data) < 0)
1029     data.res = isl_union_pw_multi_aff_free (data.res);
1030
1031   isl_union_set_free (set);
1032   return isl_multi_union_pw_aff_from_union_pw_multi_aff (data.res);
1033 }
1034
1035 /* Embed SCHEDULE in the constraints of the LOOP domain.  */
1036
1037 static isl_schedule *
1038 add_loop_schedule (__isl_take isl_schedule *schedule, loop_p loop,
1039                    scop_p scop)
1040 {
1041   poly_bb_p pbb = outermost_pbb_in (loop, scop);
1042   isl_set *iterators = pbb->iterators;
1043
1044   int empty = isl_set_is_empty (iterators);
1045   if (empty < 0 || empty)
1046     return empty < 0 ? isl_schedule_free (schedule) : schedule;
1047
1048   isl_union_set *domain = isl_schedule_get_domain (schedule);
1049   /* We cannot apply an empty domain to pbbs in this loop so return early.  */
1050   if (isl_union_set_is_empty (domain))
1051     {
1052       isl_union_set_free (domain);
1053       return schedule;
1054     }
1055
1056   isl_space *space = isl_set_get_space (iterators);
1057   int loop_index = isl_space_dim (space, isl_dim_set) - 1;
1058
1059   loop_p ploop = pbb_loop (pbb);
1060   while (loop != ploop)
1061     {
1062       --loop_index;
1063       ploop = loop_outer (ploop);
1064     }
1065
1066   isl_local_space *ls = isl_local_space_from_space (space);
1067   isl_aff *aff = isl_aff_var_on_domain (ls, isl_dim_set, loop_index);
1068   isl_multi_aff *prefix = isl_multi_aff_from_aff (aff);
1069   char name[50];
1070   snprintf (name, sizeof(name), "L_%d", loop->num);
1071   isl_id *label = isl_id_alloc (isl_schedule_get_ctx (schedule),
1072                                 name, NULL);
1073   prefix = isl_multi_aff_set_tuple_id (prefix, isl_dim_out, label);
1074
1075   int n = isl_multi_aff_dim (prefix, isl_dim_in);
1076   isl_multi_union_pw_aff *mupa = outer_projection_mupa (domain, n);
1077   mupa = isl_multi_union_pw_aff_apply_multi_aff (mupa, prefix);
1078   return isl_schedule_insert_partial_schedule (schedule, mupa);
1079 }
1080
1081 /* Build schedule for the pbb at INDEX.  */
1082
1083 static isl_schedule *
1084 build_schedule_pbb (scop_p scop, int *index)
1085 {
1086   poly_bb_p pbb = scop->pbbs[*index];
1087   ++*index;
1088   isl_set *domain = isl_set_copy (pbb->domain);
1089   isl_union_set *ud = isl_union_set_from_set (domain);
1090   return isl_schedule_from_domain (ud);
1091 }
1092
1093 static isl_schedule *build_schedule_loop_nest (scop_p, int *, loop_p);
1094
1095 /* Build the schedule of the loop containing the SCOP pbb at INDEX.  */
1096
1097 static isl_schedule *
1098 build_schedule_loop (scop_p scop, int *index)
1099 {
1100   int max = scop->pbbs.length ();
1101   gcc_assert (*index < max);
1102   loop_p loop = loop_at (scop, index);
1103
1104   isl_schedule *s = NULL;
1105   while (nested_in (loop_at (scop, index), loop))
1106     {
1107       if (loop == loop_at (scop, index))
1108         s = add_in_sequence (s, build_schedule_pbb (scop, index));
1109       else
1110         s = add_in_sequence (s, build_schedule_loop_nest (scop, index, loop));
1111
1112       if (*index == max)
1113         break;
1114     }
1115
1116   return add_loop_schedule (s, loop, scop);
1117 }
1118
1119 /* S is the schedule of the loop LOOP.  Embed the schedule S in all outer loops.
1120    When CONTEXT_LOOP is null, embed the schedule in all loops contained in the
1121    SCOP surrounding LOOP.  When CONTEXT_LOOP is non null, only embed S in the
1122    maximal loop nest contained within CONTEXT_LOOP.  */
1123
1124 static isl_schedule *
1125 embed_in_surrounding_loops (__isl_take isl_schedule *s, scop_p scop,
1126                             loop_p loop, int *index, loop_p context_loop)
1127 {
1128   loop_p outer = loop_outer (loop);
1129   sese_l region = scop->scop_info->region;
1130   if (context_loop == outer
1131       || !loop_in_sese_p (outer, region))
1132     return s;
1133
1134   int max = scop->pbbs.length ();
1135   if (*index == max
1136       || (context_loop && !nested_in (loop_at (scop, index), context_loop))
1137       || (!context_loop
1138           && !loop_in_sese_p (find_common_loop (outer, loop_at (scop, index)),
1139                               region)))
1140     return embed_in_surrounding_loops (add_loop_schedule (s, outer, scop),
1141                                        scop, outer, index, context_loop);
1142
1143   bool a_pbb;
1144   while ((a_pbb = (outer == loop_at (scop, index)))
1145          || nested_in (loop_at (scop, index), outer))
1146     {
1147       if (a_pbb)
1148         s = add_in_sequence (s, build_schedule_pbb (scop, index));
1149       else
1150         s = add_in_sequence (s, build_schedule_loop (scop, index));
1151
1152       if (*index == max)
1153         break;
1154     }
1155
1156   /* We reached the end of the OUTER loop: embed S in OUTER.  */
1157   return embed_in_surrounding_loops (add_loop_schedule (s, outer, scop), scop,
1158                                      outer, index, context_loop);
1159 }
1160
1161 /* Build schedule for the full loop nest containing the pbb at INDEX.  When
1162    CONTEXT_LOOP is null, build the schedule of all loops contained in the SCOP
1163    surrounding the pbb.  When CONTEXT_LOOP is non null, only build the maximal loop
1164    nest contained within CONTEXT_LOOP.  */
1165
1166 static isl_schedule *
1167 build_schedule_loop_nest (scop_p scop, int *index, loop_p context_loop)
1168 {
1169   gcc_assert (*index != (int) scop->pbbs.length ());
1170
1171   loop_p loop = loop_at (scop, index);
1172   isl_schedule *s = build_schedule_loop (scop, index);
1173   return embed_in_surrounding_loops (s, scop, loop, index, context_loop);
1174 }
1175
1176 /* Build the schedule of the SCOP.  */
1177
1178 static void
1179 build_original_schedule (scop_p scop)
1180 {
1181   int i = 0;
1182   int n = scop->pbbs.length ();
1183   while (i < n)
1184     {
1185       poly_bb_p pbb = scop->pbbs[i];
1186       isl_schedule *s = NULL;
1187       if (!loop_in_sese_p (pbb_loop (pbb), scop->scop_info->region))
1188         s = build_schedule_pbb (scop, &i);
1189       else
1190         s = build_schedule_loop_nest (scop, &i, NULL);
1191
1192       scop->original_schedule = add_in_sequence (scop->original_schedule, s);
1193     }
1194
1195   if (dump_file)
1196     {
1197       fprintf (dump_file, "[sese-to-poly] original schedule:\n");
1198       print_isl_schedule (dump_file, scop->original_schedule);
1199     }
1200 }
1201
1202 /* Builds the polyhedral representation for a SESE region.  */
1203
1204 bool
1205 build_poly_scop (scop_p scop)
1206 {
1207   int old_err = isl_options_get_on_error (scop->isl_context);
1208   isl_options_set_on_error (scop->isl_context, ISL_ON_ERROR_CONTINUE);
1209
1210   build_scop_context (scop);
1211
1212   unsigned i = 0;
1213   unsigned n = scop->pbbs.length ();
1214   while (i < n)
1215     i = build_iteration_domains (scop, scop->param_context, i, NULL);
1216
1217   build_scop_drs (scop);
1218   build_original_schedule (scop);
1219
1220   enum isl_error err = isl_ctx_last_error (scop->isl_context);
1221   isl_ctx_reset_error (scop->isl_context);
1222   isl_options_set_on_error (scop->isl_context, old_err);
1223   if (err != isl_error_none)
1224     dump_printf (MSG_MISSED_OPTIMIZATION,
1225                  "ISL error while building poly scop\n");
1226
1227   return err == isl_error_none;
1228 }
1229 #endif  /* HAVE_isl */