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 (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     transform_done |= scop_do_strip_mine (scop);
 259
 260   if (flag_loop_interchange)
 261     transform_done |= scop_do_interchange (scop);
 262
 263   return transform_done;
 264 }
 265
 266 /* Create a new polyhedral data reference and add it to PBB.  It is
 267    defined by its ACCESSES, its TYPE, and the number of subscripts
 268    NB_SUBSCRIPTS.  */
 269
 270 void
 271 new_poly_dr (poly_bb_p pbb,
 272              ppl_Pointset_Powerset_C_Polyhedron_t accesses,
 273              enum POLY_DR_TYPE type, void *cdr, int nb_subscripts)
 274 {
 275   poly_dr_p pdr = XNEW (struct poly_dr);
 276   static int id = 0;
 277
 278   PDR_ID (pdr) = id++;
 279   PDR_PBB (pdr) = pbb;
 280   PDR_ACCESSES (pdr) = accesses;
 281   PDR_TYPE (pdr) = type;
 282   PDR_CDR (pdr) = cdr;
 283   PDR_NB_SUBSCRIPTS (pdr) = nb_subscripts;
 284   VEC_safe_push (poly_dr_p, heap, PBB_DRS (pbb), pdr);
 285 }
 286
 287 /* Free polyhedral data reference PDR.  */
 288
 289 void
 290 free_poly_dr (poly_dr_p pdr)
 291 {
 292   ppl_delete_Pointset_Powerset_C_Polyhedron (PDR_ACCESSES (pdr));
 293   XDELETE (pdr);
 294 }
 295
 296 /* Create a new polyhedral black box.  */
 297
 298 void
 299 new_poly_bb (scop_p scop, void *black_box)
 300 {
 301   poly_bb_p pbb = XNEW (struct poly_bb);
 302
 303   PBB_DOMAIN (pbb) = NULL;
 304   PBB_SCOP (pbb) = scop;
 305   pbb_set_black_box (pbb, black_box);
 306   PBB_TRANSFORMED (pbb) = NULL;
 307   PBB_SAVED (pbb) = NULL;
 308   PBB_ORIGINAL (pbb) = NULL;
 309   PBB_DRS (pbb) = VEC_alloc (poly_dr_p, heap, 3);
 310   VEC_safe_push (poly_bb_p, heap, SCOP_BBS (scop), pbb);
 311 }
 312
 313 /* Free polyhedral black box.  */
 314
 315 void
 316 free_poly_bb (poly_bb_p pbb)
 317 {
 318   int i;
 319   poly_dr_p pdr;
 320
 321   ppl_delete_Pointset_Powerset_C_Polyhedron (PBB_DOMAIN (pbb));
 322
 323   if (PBB_TRANSFORMED (pbb))
 324     poly_scattering_free (PBB_TRANSFORMED (pbb));
 325
 326   if (PBB_SAVED (pbb))
 327     poly_scattering_free (PBB_SAVED (pbb));
 328
 329   if (PBB_ORIGINAL (pbb))
 330     poly_scattering_free (PBB_ORIGINAL (pbb));
 331
 332   if (PBB_DRS (pbb))
 333     for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
 334       free_poly_dr (pdr);
 335
 336   VEC_free (poly_dr_p, heap, PBB_DRS (pbb));
 337   XDELETE (pbb);
 338 }
 339
 340 static void
 341 print_pdr_access_layout (FILE *file, poly_dr_p pdr)
 342 {
 343   graphite_dim_t i;
 344
 345   fprintf (file, "#  eq");
 346
 347   for (i = 0; i < pdr_dim_iter_domain (pdr); i++)
 348     fprintf (file, "     i%d", (int) i);
 349
 350   for (i = 0; i < pdr_nb_params (pdr); i++)
 351     fprintf (file, "     p%d", (int) i);
 352
 353   fprintf (file, "  alias");
 354
 355   for (i = 0; i < PDR_NB_SUBSCRIPTS (pdr); i++)
 356     fprintf (file, "   sub%d", (int) i);
 357
 358   fprintf (file, "    cst\n");
 359 }
 360
 361 /* Prints to FILE the polyhedral data reference PDR.  */
 362
 363 void
 364 print_pdr (FILE *file, poly_dr_p pdr)
 365 {
 366   fprintf (file, "pdr_%d (", PDR_ID (pdr));
 367
 368   switch (PDR_TYPE (pdr))
 369     {
 370     case PDR_READ:
 371       fprintf (file, "read \n");
 372       break;
 373
 374     case PDR_WRITE:
 375       fprintf (file, "write \n");
 376       break;
 377
 378     case PDR_MAY_WRITE:
 379       fprintf (file, "may_write \n");
 380       break;
 381
 382     default:
 383       gcc_unreachable ();
 384     }
 385
 386   dump_data_reference (file, (data_reference_p) PDR_CDR (pdr));
 387
 388   fprintf (file, "data accesses (\n");
 389   print_pdr_access_layout (file, pdr);
 390   ppl_print_powerset_matrix (file, PDR_ACCESSES (pdr));
 391   fprintf (file, ")\n");
 392
 393   fprintf (file, ")\n");
 394 }
 395
 396 /* Prints to STDERR the polyhedral data reference PDR.  */
 397
 398 void
 399 debug_pdr (poly_dr_p pdr)
 400 {
 401   print_pdr (stderr, pdr);
 402 }
 403
 404 /* Creates a new SCOP containing REGION.  */
 405
 406 scop_p
 407 new_scop (void *region)
 408 {
 409   scop_p scop = XNEW (struct scop);
 410
 411   SCOP_DEP_GRAPH (scop) = NULL;
 412   SCOP_CONTEXT (scop) = NULL;
 413   scop_set_region (scop, region);
 414   SCOP_BBS (scop) = VEC_alloc (poly_bb_p, heap, 3);
 415   SCOP_ORIGINAL_PDDRS (scop) = htab_create (10, hash_poly_ddr_p,
 416                                             eq_poly_ddr_p, free_poly_ddr);
 417   return scop;
 418 }
 419
 420 /* Deletes SCOP.  */
 421
 422 void
 423 free_scop (scop_p scop)
 424 {
 425   int i;
 426   poly_bb_p pbb;
 427
 428   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 429     free_poly_bb (pbb);
 430
 431   VEC_free (poly_bb_p, heap, SCOP_BBS (scop));
 432
 433   if (SCOP_CONTEXT (scop))
 434     ppl_delete_Pointset_Powerset_C_Polyhedron (SCOP_CONTEXT (scop));
 435
 436   htab_delete (SCOP_ORIGINAL_PDDRS (scop));
 437   XDELETE (scop);
 438 }
 439
 440 /* Print to FILE the domain of PBB.  */
 441
 442 void
 443 print_pbb_domain (FILE *file, poly_bb_p pbb)
 444 {
 445   graphite_dim_t i;
 446   gimple_bb_p gbb = PBB_BLACK_BOX (pbb);
 447
 448   if (!PBB_DOMAIN (pbb))
 449     return;
 450
 451   fprintf (file, "domains bb_%d (\n", GBB_BB (gbb)->index);
 452   fprintf (file, "#  eq");
 453
 454   for (i = 0; i < pbb_dim_iter_domain (pbb); i++)
 455     fprintf (file, "     i%d", (int) i);
 456
 457   for (i = 0; i < pbb_nb_params (pbb); i++)
 458     fprintf (file, "     p%d", (int) i);
 459
 460   fprintf (file, "    cst\n");
 461
 462   if (PBB_DOMAIN (pbb))
 463     ppl_print_powerset_matrix (file, PBB_DOMAIN (pbb));
 464
 465   fprintf (file, ")\n");
 466 }
 467
 468 /* Dump the cases of a graphite basic block GBB on FILE.  */
 469
 470 static void
 471 dump_gbb_cases (FILE *file, gimple_bb_p gbb)
 472 {
 473   int i;
 474   gimple stmt;
 475   VEC (gimple, heap) *cases;
 476
 477   if (!gbb)
 478     return;
 479
 480   cases = GBB_CONDITION_CASES (gbb);
 481   if (VEC_empty (gimple, cases))
 482     return;
 483
 484   fprintf (file, "cases bb_%d (", GBB_BB (gbb)->index);
 485
 486   for (i = 0; VEC_iterate (gimple, cases, i, stmt); i++)
 487     print_gimple_stmt (file, stmt, 0, 0);
 488
 489   fprintf (file, ")\n");
 490 }
 491
 492 /* Dump conditions of a graphite basic block GBB on FILE.  */
 493
 494 static void
 495 dump_gbb_conditions (FILE *file, gimple_bb_p gbb)
 496 {
 497   int i;
 498   gimple stmt;
 499   VEC (gimple, heap) *conditions;
 500
 501   if (!gbb)
 502     return;
 503
 504   conditions = GBB_CONDITIONS (gbb);
 505   if (VEC_empty (gimple, conditions))
 506     return;
 507
 508   fprintf (file, "conditions bb_%d (", GBB_BB (gbb)->index);
 509
 510   for (i = 0; VEC_iterate (gimple, conditions, i, stmt); i++)
 511     print_gimple_stmt (file, stmt, 0, 0);
 512
 513   fprintf (file, ")\n");
 514 }
 515
 516 /* Print to FILE all the data references of PBB.  */
 517
 518 void
 519 print_pdrs (FILE *file, poly_bb_p pbb)
 520 {
 521   int i;
 522   poly_dr_p pdr;
 523
 524   for (i = 0; VEC_iterate (poly_dr_p, PBB_DRS (pbb), i, pdr); i++)
 525     print_pdr (file, pdr);
 526 }
 527
 528 /* Print to STDERR all the data references of PBB.  */
 529
 530 void
 531 debug_pdrs (poly_bb_p pbb)
 532 {
 533   print_pdrs (stderr, pbb);
 534 }
 535
 536 /* Print to FILE the domain and scattering function of PBB.  */
 537
 538 void
 539 print_pbb (FILE *file, poly_bb_p pbb)
 540 {
 541   fprintf (file, "pbb_%d (\n", GBB_BB (PBB_BLACK_BOX (pbb))->index);
 542   dump_gbb_conditions (file, PBB_BLACK_BOX (pbb));
 543   dump_gbb_cases (file, PBB_BLACK_BOX (pbb));
 544   print_pdrs (file, pbb);
 545   print_pbb_domain (file, pbb);
 546   print_scattering_function (file, pbb);
 547   fprintf (file, ")\n");
 548 }
 549
 550 /* Print to FILE the parameters of SCOP.  */
 551
 552 void
 553 print_scop_params (FILE *file, scop_p scop)
 554 {
 555   int i;
 556   tree t;
 557
 558   fprintf (file, "parameters (\n");
 559   for (i = 0; VEC_iterate (tree, SESE_PARAMS (SCOP_REGION (scop)), i, t); i++)
 560     {
 561       fprintf (file, "p_%d -> ", i);
 562       print_generic_expr (file, t, 0);
 563       fprintf (file, "\n");
 564     }
 565   fprintf (file, ")\n");
 566 }
 567
 568 /* Print to FILE the context of SCoP.  */
 569 void
 570 print_scop_context (FILE *file, scop_p scop)
 571 {
 572   graphite_dim_t i;
 573
 574   fprintf (file, "context (\n");
 575   fprintf (file, "#  eq");
 576
 577   for (i = 0; i < scop_nb_params (scop); i++)
 578     fprintf (file, "     p%d", (int) i);
 579
 580   fprintf (file, "    cst\n");
 581
 582   if (SCOP_CONTEXT (scop))
 583     ppl_print_powerset_matrix (file, SCOP_CONTEXT (scop));
 584
 585   fprintf (file, ")\n");
 586 }
 587
 588 /* Print to FILE the SCOP.  */
 589
 590 void
 591 print_scop (FILE *file, scop_p scop)
 592 {
 593   int i;
 594   poly_bb_p pbb;
 595
 596   fprintf (file, "scop (\n");
 597   print_scop_params (file, scop);
 598   print_scop_context (file, scop);
 599
 600   for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
 601     print_pbb (file, pbb);
 602
 603   fprintf (file, ")\n");
 604 }
 605
 606 /* Print to STDERR the domain of PBB.  */
 607
 608 void
 609 debug_pbb_domain (poly_bb_p pbb)
 610 {
 611   print_pbb_domain (stderr, pbb);
 612 }
 613
 614 /* Print to FILE the domain and scattering function of PBB.  */
 615
 616 void
 617 debug_pbb (poly_bb_p pbb)
 618 {
 619   print_pbb (stderr, pbb);
 620 }
 621
 622 /* Print to STDERR the context of SCOP.  */
 623
 624 void
 625 debug_scop_context (scop_p scop)
 626 {
 627   print_scop_context (stderr, scop);
 628 }
 629
 630 /* Print to STDERR the SCOP.  */
 631
 632 void
 633 debug_scop (scop_p scop)
 634 {
 635   print_scop (stderr, scop);
 636 }
 637
 638 /* Print to STDERR the parameters of SCOP.  */
 639
 640 void
 641 debug_scop_params (scop_p scop)
 642 {
 643   print_scop_params (stderr, scop);
 644 }
 645
 646
 647 /* The dimension in the transformed scattering polyhedron of PBB
 648    containing the scattering iterator for the loop at depth LOOP_DEPTH.  */
 649
 650 ppl_dimension_type
 651 psct_scattering_dim_for_loop_depth (poly_bb_p pbb, graphite_dim_t loop_depth)
 652 {
 653   ppl_const_Constraint_System_t pcs;
 654   ppl_Constraint_System_const_iterator_t cit, cend;
 655   ppl_const_Constraint_t cstr;
 656   ppl_Polyhedron_t ph = PBB_TRANSFORMED_SCATTERING (pbb);
 657   ppl_dimension_type iter = psct_iterator_dim (pbb, loop_depth);
 658   ppl_Linear_Expression_t expr;
 659   ppl_Coefficient_t coef;
 660   Value val;
 661   graphite_dim_t i;
 662
 663   value_init (val);
 664   ppl_new_Coefficient (&coef);
 665   ppl_Polyhedron_get_constraints (ph, &pcs);
 666   ppl_new_Constraint_System_const_iterator (&cit);
 667   ppl_new_Constraint_System_const_iterator (&cend);
 668
 669   for (ppl_Constraint_System_begin (pcs, cit),
 670          ppl_Constraint_System_end (pcs, cend);
 671        !ppl_Constraint_System_const_iterator_equal_test (cit, cend);
 672        ppl_Constraint_System_const_iterator_increment (cit))
 673     {
 674       ppl_Constraint_System_const_iterator_dereference (cit, &cstr);
 675       ppl_new_Linear_Expression_from_Constraint (&expr, cstr);
 676       ppl_Linear_Expression_coefficient (expr, iter, coef);
 677       ppl_Coefficient_to_mpz_t (coef, val);
 678
 679       if (value_zero_p (val))
 680         {
 681           ppl_delete_Linear_Expression (expr);
 682           continue;
 683         }
 684
 685       for (i = 0; i < pbb_nb_scattering_transform (pbb); i++)
 686         {
 687           ppl_dimension_type scatter = psct_scattering_dim (pbb, i);
 688
 689           ppl_Linear_Expression_coefficient (expr, scatter, coef);
 690           ppl_Coefficient_to_mpz_t (coef, val);
 691
 692           if (value_notzero_p (val))
 693             {
 694               value_clear (val);
 695               ppl_delete_Linear_Expression (expr);
 696               ppl_delete_Coefficient (coef);
 697               ppl_delete_Constraint_System_const_iterator (cit);
 698               ppl_delete_Constraint_System_const_iterator (cend);
 699
 700               return scatter;
 701             }
 702         }
 703     }
 704
 705   gcc_unreachable ();
 706 }
 707
 708 /* Returns the number of iterations NITER of the loop around PBB at
 709    depth LOOP_DEPTH.  */
 710
 711 void
 712 pbb_number_of_iterations (poly_bb_p pbb,
 713                           graphite_dim_t loop_depth,
 714                           Value niter)
 715 {
 716   ppl_Linear_Expression_t le;
 717   ppl_dimension_type dim;
 718
 719   ppl_Pointset_Powerset_C_Polyhedron_space_dimension (PBB_DOMAIN (pbb), &dim);
 720   ppl_new_Linear_Expression_with_dimension (&le, dim);
 721   ppl_set_coef (le, pbb_iterator_dim (pbb, loop_depth), 1);
 722   value_set_si (niter, -1);
 723   ppl_max_for_le (PBB_DOMAIN (pbb), le, niter);
 724   ppl_delete_Linear_Expression (le);
 725 }
 726
 727 #endif
 728