gcc/graphite-poly.c

   1 /* Graphite polyhedral representation.
   2    Copyright (C) 2009 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <sebastian.pop@amd.com> and
   4    Tobias Grosser <grosser@fim.uni-passau.de>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "ggc.h"
  26 #include "tree.h"
  27 #include "rtl.h"
  28 #include "output.h"
  29 #include "basic-block.h"
  30 #include "diagnostic.h"
  31 #include "tree-flow.h"
  32 #include "toplev.h"
  33 #include "tree-dump.h"
  34 #include "timevar.h"
  35 #include "cfgloop.h"
  36 #include "tree-chrec.h"
  37 #include "tree-data-ref.h"
  38 #include "tree-scalar-evolution.h"
  39 #include "tree-pass.h"
  40 #include "domwalk.h"
  41 #include "value-prof.h"
  42 #include "pointer-set.h"
  43 #include "gimple.h"
  44 #include "params.h"
  45
  46 #ifdef HAVE_cloog
  47 #include "cloog/cloog.h"
  48 #include "ppl_c.h"
  49 #include "sese.h"
  50 #include "graphite-ppl.h"
  51 #include "graphite.h"
  52 #include "graphite-poly.h"
  53 #include "graphite-dependences.h"
  54
  55 /* Return the maximal loop depth in SCOP.  */
  56
  57 int
  58 scop_max_loop_depth (scop_p scop)
  59 {
  60   int i;
  61   poly_bb_p pbb;
  62   int max_nb_loops = 0;
  63
  64   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
  65     {
  66       int nb_loops = pbb_dim_iter_domain (pbb);
  67       if (max_nb_loops < nb_loops)
  68         max_nb_loops = nb_loops;
  69     }
  70
  71   return max_nb_loops;
  72 }
  73
  74 /* Extend the scattering matrix of PBB to MAX_SCATTERING scattering
  75    dimensions.  */
  76
  77 static void
  78 extend_scattering (poly_bb_p pbb, int max_scattering)
  79 {
  80   ppl_dimension_type nb_old_dims, nb_new_dims;
  81   int nb_added_dims, i;
  82   ppl_Coefficient_t coef;
  83   Value one;
  84
  85   nb_added_dims = max_scattering - pbb_nb_scattering_transform (pbb);
  86   value_init (one);
  87   value_set_si (one, 1);
  88   ppl_new_Coefficient (&coef);
  89   ppl_assign_Coefficient_from_mpz_t (coef, one);
  90
  91   gcc_assert (nb_added_dims >= 0);
  92
  93   nb_old_dims = pbb_nb_scattering_transform (pbb) + pbb_dim_iter_domain (pbb)
  94     + scop_nb_params (PBB_SCOP (pbb));
  95   nb_new_dims = nb_old_dims + nb_added_dims;
  96
  97   ppl_insert_dimensions (PBB_TRANSFORMED_SCATTERING (pbb),
  98                          pbb_nb_scattering_transform (pbb), nb_added_dims);
  99   PBB_NB_SCATTERING_TRANSFORM (pbb) += nb_added_dims;
 100
 101   /* Add identity matrix for the added dimensions.  */
 102   for (i = max_scattering - nb_added_dims; i < max_scattering; i++)
 103     {
 104       ppl_Constraint_t cstr;
 105       ppl_Linear_Expression_t expr;
 106
 107       ppl_new_Linear_Expression_with_dimension (&expr, nb_new_dims);
 108       ppl_Linear_Expression_add_to_coefficient (expr, i, coef);
 109       ppl_new_Constraint (&cstr, expr, PPL_CONSTRAINT_TYPE_EQUAL);
 110       ppl_Polyhedron_add_constraint (PBB_TRANSFORMED_SCATTERING (pbb), cstr);
 111       ppl_delete_Constraint (cstr);
 112       ppl_delete_Linear_Expression (expr);
 113     }
 114
 115   ppl_delete_Coefficient (coef);
 116   value_clear (one);
 117 }
 118
 119 /* All scattering matrices in SCOP will have the same number of scattering
 120    dimensions.  */
 121
 122 int
 123 unify_scattering_dimensions (scop_p scop)
 124 {
 125   int i;
 126   poly_bb_p pbb;
 127   graphite_dim_t max_scattering = 0;
 128
 129   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 130     max_scattering = MAX (pbb_nb_scattering_transform (pbb), max_scattering);
 131
 132   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 133     extend_scattering (pbb, max_scattering);
 134
 135   return max_scattering;
 136 }
 137
 138 /* Prints to FILE the scattering function of PBB.  */
 139
 140 void
 141 print_scattering_function (FILE *file, poly_bb_p pbb)
 142 {
 143   graphite_dim_t i;
 144
 145   if (!PBB_TRANSFORMED_SCATTERING (pbb))
 146     return;
 147
 148   fprintf (file, "scattering bb_%d (\n", GBB_BB (PBB_BLACK_BOX (pbb))->index);
 149   fprintf (file, "#  eq");
 150
 151   for (i = 0; i < pbb_nb_scattering_transform (pbb); i++)
 152     fprintf (file, "     s%d", (int) i);
 153
 154   for (i = 0; i < pbb_nb_local_vars (pbb); i++)
 155     fprintf (file, "    lv%d", (int) i);
 156
 157   for (i = 0; i < pbb_dim_iter_domain (pbb); i++)
 158     fprintf (file, "     i%d", (int) i);
 159
 160   for (i = 0; i < pbb_nb_params (pbb); i++)
 161     fprintf (file, "     p%d", (int) i);
 162
 163   fprintf (file, "    cst\n");
 164
 165   ppl_print_polyhedron_matrix (file, PBB_TRANSFORMED_SCATTERING (pbb));
 166
 167   fprintf (file, ")\n");
 168 }
 169
 170 /* Prints to FILE the iteration domain of PBB.  */
 171
 172 void
 173 print_iteration_domain (FILE *file, poly_bb_p pbb)
 174 {
 175   print_pbb_domain (file, pbb);
 176 }
 177
 178 /* Prints to FILE the scattering functions of every PBB of SCOP.  */
 179
 180 void
 181 print_scattering_functions (FILE *file, scop_p scop)
 182 {
 183   int i;
 184   poly_bb_p pbb;
 185
 186   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 187     print_scattering_function (file, pbb);
 188 }
 189
 190 /* Prints to FILE the iteration domains of every PBB of SCOP.  */
 191
 192 void
 193 print_iteration_domains (FILE *file, scop_p scop)
 194 {
 195   int i;
 196   poly_bb_p pbb;
 197
 198   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 199     print_iteration_domain (file, pbb);
 200 }
 201
 202 /* Prints to STDERR the scattering function of PBB.  */
 203
 204 void
 205 debug_scattering_function (poly_bb_p pbb)
 206 {
 207   print_scattering_function (stderr, pbb);
 208 }
 209
 210 /* Prints to STDERR the iteration domain of PBB.  */
 211
 212 void
 213 debug_iteration_domain (poly_bb_p pbb)
 214 {
 215   print_iteration_domain (stderr, pbb);
 216 }
 217
 218 /* Prints to STDERR the scattering functions of every PBB of SCOP.  */
 219
 220 void
 221 debug_scattering_functions (scop_p scop)
 222 {
 223   print_scattering_functions (stderr, scop);
 224 }
 225
 226 /* Prints to STDERR the iteration domains of every PBB of SCOP.  */
 227
 228 void
 229 debug_iteration_domains (scop_p scop)
 230 {
 231   print_iteration_domains (stderr, scop);
 232 }
 233
 234 /* Apply graphite transformations to all the basic blocks of SCOP.  */
 235
 236 bool
 237 apply_poly_transforms (scop_p scop)
 238 {
 239   bool transform_done = false;
 240
 241   gcc_assert (graphite_legal_transform (scop));
 242
 243   /* Generate code even if we did not apply any real transformation.
 244      This also allows to check the performance for the identity
 245      transformation: GIMPLE -> GRAPHITE -> GIMPLE
 246      Keep in mind that CLooG optimizes in control, so the loop structure
 247      may change, even if we only use -fgraphite-identity.  */
 248   if (flag_graphite_identity)
 249     transform_done = true;
 250
 251   if (flag_loop_parallelize_all)
 252     transform_done = true;
 253
 254   if (flag_loop_block)
 255     gcc_unreachable (); /* Not yet supported.  */
 256
 257   if (flag_loop_strip_mine)
 258     {
 259       transform_done |= scop_do_strip_mine (scop);
 260       gcc_assert (graphite_legal_transform (scop));
 261     }
 262
 263   if (flag_loop_interchange)
 264     {
 265       transform_done |= scop_do_interchange (scop);
 266       gcc_assert (graphite_legal_transform (scop));
 267     }
 268
 269   return transform_done;
 270 }
 271
 272 /* Create a new polyhedral data reference and add it to PBB. It is defined by
 273    its ACCESSES, its TYPE*/
 274
 275 void
 276 new_poly_dr (poly_bb_p pbb,
 277              ppl_Pointset_Powerset_C_Polyhedron_t accesses,
 278              ppl_Pointset_Powerset_C_Polyhedron_t data_container,
 279              enum POLY_DR_TYPE type, void *cdr)
 280 {
 281   poly_dr_p pdr = XNEW (struct poly_dr);
 282
 283   PDR_PBB (pdr) = pbb;
 284   PDR_ACCESSES (pdr) = accesses;
 285   PDR_DATA_CONTAINER (pdr) = data_container;
 286   PDR_TYPE (pdr) = type;
 287   PDR_CDR (pdr) = cdr;
 288   VEC_safe_push (poly_dr_p, heap, PBB_DRS (pbb), pdr);
 289 }
 290
 291 /* Free polyhedral data reference PDR.  */
 292
 293 void
 294 free_poly_dr (poly_dr_p pdr)
 295 {
 296   ppl_delete_Pointset_Powerset_C_Polyhedron (PDR_ACCESSES (pdr));
 297   ppl_delete_Pointset_Powerset_C_Polyhedron (PDR_DATA_CONTAINER (pdr));
 298
 299   XDELETE (pdr);
 300 }
 301
 302 /* Create a new polyhedral black box.  */
 303
 304 void
 305 new_poly_bb (scop_p scop, void *black_box)
 306 {
 307   poly_bb_p pbb = XNEW (struct poly_bb);
 308
 309   PBB_DOMAIN (pbb) = NULL;
 310   PBB_SCOP (pbb) = scop;
 311   pbb_set_black_box (pbb, black_box);
 312   PBB_TRANSFORMED_SCATTERING (pbb) = NULL;
 313   PBB_ORIGINAL_SCATTERING (pbb) = NULL;
 314   PBB_DRS (pbb) = VEC_alloc (poly_dr_p, heap, 3);
 315   PBB_NB_SCATTERING_TRANSFORM (pbb) = 0;
 316   PBB_NB_LOCAL_VARIABLES (pbb) = 0;
 317   VEC_safe_push (poly_bb_p, heap, SCOP_BBS (scop), pbb);
 318 }
 319
 320 /* Free polyhedral black box.  */
 321
 322 void
 323 free_poly_bb (poly_bb_p pbb)
 324 {
 325   int i;
 326   poly_dr_p pdr;
 327
 328   ppl_delete_Pointset_Powerset_C_Polyhedron (PBB_DOMAIN (pbb));
 329
 330   if (PBB_TRANSFORMED_SCATTERING (pbb))
 331     ppl_delete_Polyhedron (PBB_TRANSFORMED_SCATTERING (pbb));
 332
 333   if (PBB_ORIGINAL_SCATTERING (pbb))
 334     ppl_delete_Polyhedron (PBB_ORIGINAL_SCATTERING (pbb));
 335
 336   if (PBB_DRS (pbb))
 337     for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
 338       free_poly_dr (pdr);
 339
 340   VEC_free (poly_dr_p, heap, PBB_DRS (pbb));
 341   XDELETE (pbb);
 342 }
 343
 344 static void
 345 print_pdr_access_layout (FILE *file, poly_dr_p pdr)
 346 {
 347   graphite_dim_t i;
 348
 349   fprintf (file, "#  eq");
 350
 351   for (i = 0; i < pdr_dim_iter_domain (pdr); i++)
 352     fprintf (file, "     i%d", (int) i);
 353
 354   for (i = 0; i < pdr_nb_params (pdr); i++)
 355     fprintf (file, "     p%d", (int) i);
 356
 357   fprintf (file, "  alias");
 358
 359   for (i = 0; i < pdr_nb_subscripts (pdr); i++)
 360     fprintf (file, "   sub%d", (int) i);
 361
 362   fprintf (file, "    cst\n");
 363 }
 364
 365 /* Prints to FILE the polyhedral data reference PDR.  */
 366
 367 void
 368 print_pdr (FILE *file, poly_dr_p pdr)
 369 {
 370   fprintf (file, "pdr (");
 371
 372   switch (PDR_TYPE (pdr))
 373     {
 374     case PDR_READ:
 375       fprintf (file, "read \n");
 376       break;
 377
 378     case PDR_WRITE:
 379       fprintf (file, "write \n");
 380       break;
 381
 382     case PDR_MAY_WRITE:
 383       fprintf (file, "may_write \n");
 384       break;
 385
 386     default:
 387       gcc_unreachable ();
 388     }
 389
 390   dump_data_reference (file, (data_reference_p) PDR_CDR (pdr));
 391
 392   fprintf (file, "data accesses (\n");
 393   print_pdr_access_layout (file, pdr);
 394   ppl_print_powerset_matrix (file, PDR_ACCESSES (pdr));
 395   fprintf (file, ")\n");
 396
 397   fprintf (file, "data container (\n");
 398   print_pdr_access_layout (file, pdr);
 399   ppl_print_powerset_matrix (file, PDR_DATA_CONTAINER (pdr));
 400   fprintf (file, ")\n");
 401
 402   fprintf (file, ")\n");
 403 }
 404
 405 /* Prints to STDERR the polyhedral data reference PDR.  */
 406
 407 void
 408 debug_pdr (poly_dr_p pdr)
 409 {
 410   print_pdr (stderr, pdr);
 411 }
 412
 413 /* Creates a new SCOP containing REGION.  */
 414
 415 scop_p
 416 new_scop (void *region)
 417 {
 418   scop_p scop = XNEW (struct scop);
 419
 420   SCOP_DEP_GRAPH (scop) = NULL;
 421   SCOP_CONTEXT (scop) = NULL;
 422   scop_set_region (scop, region);
 423   SCOP_BBS (scop) = VEC_alloc (poly_bb_p, heap, 3);
 424   SCOP_ORIGINAL_PDR_PAIRS (scop) = htab_create (10, hash_poly_dr_pair_p,
 425                                                 eq_poly_dr_pair_p, free);
 426   return scop;
 427 }
 428
 429 /* Deletes SCOP.  */
 430
 431 void
 432 free_scop (scop_p scop)
 433 {
 434   int i;
 435   poly_bb_p pbb;
 436
 437   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 438     free_poly_bb (pbb);
 439
 440   VEC_free (poly_bb_p, heap, SCOP_BBS (scop));
 441
 442   if (SCOP_CONTEXT (scop))
 443     ppl_delete_Pointset_Powerset_C_Polyhedron (SCOP_CONTEXT (scop));
 444
 445   htab_delete (SCOP_ORIGINAL_PDR_PAIRS (scop));
 446   XDELETE (scop);
 447 }
 448
 449 /* Print to FILE the domain of PBB.  */
 450
 451 void
 452 print_pbb_domain (FILE *file, poly_bb_p pbb)
 453 {
 454   graphite_dim_t i;
 455   gimple_bb_p gbb = PBB_BLACK_BOX (pbb);
 456
 457   if (!PBB_DOMAIN (pbb))
 458     return;
 459
 460   fprintf (file, "domains bb_%d (\n", GBB_BB (gbb)->index);
 461   fprintf (file, "#  eq");
 462
 463   for (i = 0; i < pbb_dim_iter_domain (pbb); i++)
 464     fprintf (file, "     i%d", (int) i);
 465
 466   for (i = 0; i < pbb_nb_params (pbb); i++)
 467     fprintf (file, "     p%d", (int) i);
 468
 469   fprintf (file, "    cst\n");
 470
 471   if (PBB_DOMAIN (pbb))
 472     ppl_print_powerset_matrix (file, PBB_DOMAIN (pbb));
 473
 474   fprintf (file, ")\n");
 475 }
 476
 477 /* Dump the cases of a graphite basic block GBB on FILE.  */
 478
 479 static void
 480 dump_gbb_cases (FILE *file, gimple_bb_p gbb)
 481 {
 482   int i;
 483   gimple stmt;
 484   VEC (gimple, heap) *cases;
 485
 486   if (!gbb)
 487     return;
 488
 489   cases = GBB_CONDITION_CASES (gbb);
 490   if (VEC_empty (gimple, cases))
 491     return;
 492
 493   fprintf (file, "cases bb_%d (", GBB_BB (gbb)->index);
 494
 495   for (i = 0; VEC_iterate (gimple, cases, i, stmt); i++)
 496     print_gimple_stmt (file, stmt, 0, 0);
 497
 498   fprintf (file, ")\n");
 499 }
 500
 501 /* Dump conditions of a graphite basic block GBB on FILE.  */
 502
 503 static void
 504 dump_gbb_conditions (FILE *file, gimple_bb_p gbb)
 505 {
 506   int i;
 507   gimple stmt;
 508   VEC (gimple, heap) *conditions;
 509
 510   if (!gbb)
 511     return;
 512
 513   conditions = GBB_CONDITIONS (gbb);
 514   if (VEC_empty (gimple, conditions))
 515     return;
 516
 517   fprintf (file, "conditions bb_%d (", GBB_BB (gbb)->index);
 518
 519   for (i = 0; VEC_iterate (gimple, conditions, i, stmt); i++)
 520     print_gimple_stmt (file, stmt, 0, 0);
 521
 522   fprintf (file, ")\n");
 523 }
 524
 525 /* Print to FILE all the data references of PBB.  */
 526
 527 void
 528 print_pdrs (FILE *file, poly_bb_p pbb)
 529 {
 530   int i;
 531   poly_dr_p pdr;
 532
 533   for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
 534     print_pdr (file, pdr);
 535 }
 536
 537 /* Print to STDERR all the data references of PBB.  */
 538
 539 void
 540 debug_pdrs (poly_bb_p pbb)
 541 {
 542   print_pdrs (stderr, pbb);
 543 }
 544
 545 /* Print to FILE the domain and scattering function of PBB.  */
 546
 547 void
 548 print_pbb (FILE *file, poly_bb_p pbb)
 549 {
 550   dump_gbb_conditions (file, PBB_BLACK_BOX (pbb));
 551   dump_gbb_cases (file, PBB_BLACK_BOX (pbb));
 552   print_pdrs (file, pbb);
 553   print_pbb_domain (file, pbb);
 554   print_scattering_function (file, pbb);
 555 }
 556
 557 /* Print to FILE the parameters of SCOP.  */
 558
 559 void
 560 print_scop_params (FILE *file, scop_p scop)
 561 {
 562   int i;
 563   tree t;
 564
 565   fprintf (file, "parameters (\n");
 566   for (i = 0; VEC_iterate (tree, SESE_PARAMS (SCOP_REGION (scop)), i, t); i++)
 567     {
 568       fprintf (file, "p_%d -> ", i);
 569       print_generic_expr (file, t, 0);
 570       fprintf (file, "\n");
 571     }
 572   fprintf (file, ")\n");
 573 }
 574
 575 /* Print to FILE the context of SCoP.  */
 576 void
 577 print_scop_context (FILE *file, scop_p scop)
 578 {
 579   graphite_dim_t i;
 580
 581   fprintf (file, "context (\n");
 582   fprintf (file, "#  eq");
 583
 584   for (i = 0; i < scop_nb_params (scop); i++)
 585     fprintf (file, "     p%d", (int) i);
 586
 587   fprintf (file, "    cst\n");
 588
 589   if (SCOP_CONTEXT (scop))
 590     ppl_print_powerset_matrix (file, SCOP_CONTEXT (scop));
 591
 592   fprintf (file, ")\n");
 593 }
 594
 595 /* Print to FILE the SCOP.  */
 596
 597 void
 598 print_scop (FILE *file, scop_p scop)
 599 {
 600   int i;
 601   poly_bb_p pbb;
 602
 603   print_scop_params (file, scop);
 604   print_scop_context (file, scop);
 605
 606   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 607     print_pbb (file, pbb);
 608 }
 609
 610 /* Print to STDERR the domain of PBB.  */
 611
 612 void
 613 debug_pbb_domain (poly_bb_p pbb)
 614 {
 615   print_pbb_domain (stderr, pbb);
 616 }
 617
 618 /* Print to FILE the domain and scattering function of PBB.  */
 619
 620 void
 621 debug_pbb (poly_bb_p pbb)
 622 {
 623   print_pbb (stderr, pbb);
 624 }
 625
 626 /* Print to STDERR the context of SCOP.  */
 627
 628 void
 629 debug_scop_context (scop_p scop)
 630 {
 631   print_scop_context (stderr, scop);
 632 }
 633
 634 /* Print to STDERR the SCOP.  */
 635
 636 void
 637 debug_scop (scop_p scop)
 638 {
 639   print_scop (stderr, scop);
 640 }
 641
 642 /* Print to STDERR the parameters of SCOP.  */
 643
 644 void
 645 debug_scop_params (scop_p scop)
 646 {
 647   print_scop_params (stderr, scop);
 648 }
 649
 650
 651 /* The dimension in the transformed scattering polyhedron of PBB
 652    containing the scattering iterator for the loop at depth LOOP_DEPTH.  */
 653
 654 ppl_dimension_type
 655 psct_scattering_dim_for_loop_depth (poly_bb_p pbb, graphite_dim_t loop_depth)
 656 {
 657   ppl_const_Constraint_System_t pcs;
 658   ppl_Constraint_System_const_iterator_t cit, cend;
 659   ppl_const_Constraint_t cstr;
 660   ppl_Polyhedron_t ph = PBB_TRANSFORMED_SCATTERING (pbb);
 661   ppl_dimension_type iter = psct_iterator_dim (pbb, loop_depth);
 662   ppl_Linear_Expression_t expr;
 663   ppl_Coefficient_t coef;
 664   Value val;
 665   graphite_dim_t i;
 666
 667   value_init (val);
 668   ppl_new_Coefficient (&coef);
 669   ppl_Polyhedron_get_constraints (ph, &pcs);
 670   ppl_new_Constraint_System_const_iterator (&cit);
 671   ppl_new_Constraint_System_const_iterator (&cend);
 672
 673   for (ppl_Constraint_System_begin (pcs, cit),
 674          ppl_Constraint_System_end (pcs, cend);
 675        !ppl_Constraint_System_const_iterator_equal_test (cit, cend);
 676        ppl_Constraint_System_const_iterator_increment (cit))
 677     {
 678       ppl_Constraint_System_const_iterator_dereference (cit, &cstr);
 679       ppl_new_Linear_Expression_from_Constraint (&expr, cstr);
 680       ppl_Linear_Expression_coefficient (expr, iter, coef);
 681       ppl_Coefficient_to_mpz_t (coef, val);
 682
 683       if (value_zero_p (val))
 684         {
 685           ppl_delete_Linear_Expression (expr);
 686           continue;
 687         }
 688
 689       for (i = 0; i < pbb_nb_scattering_transform (pbb); i++)
 690         {
 691           ppl_dimension_type scatter = psct_scattering_dim (pbb, i);
 692
 693           ppl_Linear_Expression_coefficient (expr, scatter, coef);
 694           ppl_Coefficient_to_mpz_t (coef, val);
 695
 696           if (value_notzero_p (val))
 697             {
 698               value_clear (val);
 699               ppl_delete_Linear_Expression (expr);
 700               ppl_delete_Coefficient (coef);
 701               ppl_delete_Constraint_System_const_iterator (cit);
 702               ppl_delete_Constraint_System_const_iterator (cend);
 703
 704               return scatter;
 705             }
 706         }
 707     }
 708
 709   gcc_unreachable ();
 710 }
 711
 712 /* Returns the number of iterations NITER of the loop around PBB at
 713    depth LOOP_DEPTH.  */
 714
 715 void
 716 pbb_number_of_iterations (poly_bb_p pbb,
 717                           graphite_dim_t loop_depth,
 718                           Value niter)
 719 {
 720   ppl_dimension_type loop_iter = pbb_iterator_dim (pbb, loop_depth);
 721   ppl_Linear_Expression_t le;
 722   ppl_Coefficient_t num, denom;
 723   Value dv;
 724   int maximum;
 725   ppl_dimension_type dim;
 726
 727   value_init (dv);
 728   ppl_new_Coefficient (&num);
 729   ppl_new_Coefficient (&denom);
 730   ppl_Pointset_Powerset_C_Polyhedron_space_dimension (PBB_DOMAIN (pbb), &dim);
 731   ppl_new_Linear_Expression_with_dimension (&le, dim);
 732   ppl_set_coef (le, loop_iter, 1);
 733   ppl_Pointset_Powerset_C_Polyhedron_maximize (PBB_DOMAIN (pbb), le,
 734                                                num, denom, &maximum);
 735
 736   if (maximum == 1)
 737     {
 738       ppl_Coefficient_to_mpz_t (num, niter);
 739       ppl_Coefficient_to_mpz_t (denom, dv);
 740       value_division (niter, niter, dv);
 741     }
 742   else
 743     value_set_si (niter, -1);
 744
 745   value_clear (dv);
 746   ppl_delete_Linear_Expression (le);
 747   ppl_delete_Coefficient (num);
 748   ppl_delete_Coefficient (denom);
 749 }
 750
 751 #endif
 752