gcc/sese.c

   1 /* Single entry single exit control flow regions.
   2    Copyright (C) 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Jan Sjodin <jan.sjodin@amd.com> and
   5    Sebastian Pop <sebastian.pop@amd.com>.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 3, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tree-pretty-print.h"
  27 #include "tree-flow.h"
  28 #include "cfgloop.h"
  29 #include "tree-chrec.h"
  30 #include "tree-data-ref.h"
  31 #include "tree-scalar-evolution.h"
  32 #include "tree-pass.h"
  33 #include "value-prof.h"
  34 #include "sese.h"
  35
  36 /* Print to stderr the element ELT.  */
  37
  38 static void
  39 debug_rename_elt (rename_map_elt elt)
  40 {
  41   fprintf (stderr, "(");
  42   print_generic_expr (stderr, elt->old_name, 0);
  43   fprintf (stderr, ", ");
  44   print_generic_expr (stderr, elt->expr, 0);
  45   fprintf (stderr, ")\n");
  46 }
  47
  48 /* Helper function for debug_rename_map.  */
  49
  50 static int
  51 debug_rename_map_1 (void **slot, void *s ATTRIBUTE_UNUSED)
  52 {
  53   struct rename_map_elt_s *entry = (struct rename_map_elt_s *) *slot;
  54   debug_rename_elt (entry);
  55   return 1;
  56 }
  57
  58 /* Print to stderr all the elements of RENAME_MAP.  */
  59
  60 DEBUG_FUNCTION void
  61 debug_rename_map (htab_t rename_map)
  62 {
  63   htab_traverse (rename_map, debug_rename_map_1, NULL);
  64 }
  65
  66 /* Computes a hash function for database element ELT.  */
  67
  68 hashval_t
  69 rename_map_elt_info (const void *elt)
  70 {
  71   return SSA_NAME_VERSION (((const struct rename_map_elt_s *) elt)->old_name);
  72 }
  73
  74 /* Compares database elements E1 and E2.  */
  75
  76 int
  77 eq_rename_map_elts (const void *e1, const void *e2)
  78 {
  79   const struct rename_map_elt_s *elt1 = (const struct rename_map_elt_s *) e1;
  80   const struct rename_map_elt_s *elt2 = (const struct rename_map_elt_s *) e2;
  81
  82   return (elt1->old_name == elt2->old_name);
  83 }
  84
  85 \f
  86
  87 /* Print to stderr the element ELT.  */
  88
  89 static void
  90 debug_ivtype_elt (ivtype_map_elt elt)
  91 {
  92   fprintf (stderr, "(%s, ", elt->cloog_iv);
  93   print_generic_expr (stderr, elt->type, 0);
  94   fprintf (stderr, ")\n");
  95 }
  96
  97 /* Helper function for debug_ivtype_map.  */
  98
  99 static int
 100 debug_ivtype_map_1 (void **slot, void *s ATTRIBUTE_UNUSED)
 101 {
 102   struct ivtype_map_elt_s *entry = (struct ivtype_map_elt_s *) *slot;
 103   debug_ivtype_elt (entry);
 104   return 1;
 105 }
 106
 107 /* Print to stderr all the elements of MAP.  */
 108
 109 DEBUG_FUNCTION void
 110 debug_ivtype_map (htab_t map)
 111 {
 112   htab_traverse (map, debug_ivtype_map_1, NULL);
 113 }
 114
 115 /* Computes a hash function for database element ELT.  */
 116
 117 hashval_t
 118 ivtype_map_elt_info (const void *elt)
 119 {
 120   return htab_hash_pointer (((const struct ivtype_map_elt_s *) elt)->cloog_iv);
 121 }
 122
 123 /* Compares database elements E1 and E2.  */
 124
 125 int
 126 eq_ivtype_map_elts (const void *e1, const void *e2)
 127 {
 128   const struct ivtype_map_elt_s *elt1 = (const struct ivtype_map_elt_s *) e1;
 129   const struct ivtype_map_elt_s *elt2 = (const struct ivtype_map_elt_s *) e2;
 130
 131   return (elt1->cloog_iv == elt2->cloog_iv);
 132 }
 133
 134 \f
 135
 136 /* Record LOOP as occuring in REGION.  */
 137
 138 static void
 139 sese_record_loop (sese region, loop_p loop)
 140 {
 141   if (sese_contains_loop (region, loop))
 142     return;
 143
 144   bitmap_set_bit (SESE_LOOPS (region), loop->num);
 145   VEC_safe_push (loop_p, heap, SESE_LOOP_NEST (region), loop);
 146 }
 147
 148 /* Build the loop nests contained in REGION.  Returns true when the
 149    operation was successful.  */
 150
 151 void
 152 build_sese_loop_nests (sese region)
 153 {
 154   unsigned i;
 155   basic_block bb;
 156   struct loop *loop0, *loop1;
 157
 158   FOR_EACH_BB (bb)
 159     if (bb_in_sese_p (bb, region))
 160       {
 161         struct loop *loop = bb->loop_father;
 162
 163         /* Only add loops if they are completely contained in the SCoP.  */
 164         if (loop->header == bb
 165             && bb_in_sese_p (loop->latch, region))
 166           sese_record_loop (region, loop);
 167       }
 168
 169   /* Make sure that the loops in the SESE_LOOP_NEST are ordered.  It
 170      can be the case that an inner loop is inserted before an outer
 171      loop.  To avoid this, semi-sort once.  */
 172   FOR_EACH_VEC_ELT (loop_p, SESE_LOOP_NEST (region), i, loop0)
 173     {
 174       if (VEC_length (loop_p, SESE_LOOP_NEST (region)) == i + 1)
 175         break;
 176
 177       loop1 = VEC_index (loop_p, SESE_LOOP_NEST (region), i + 1);
 178       if (loop0->num > loop1->num)
 179         {
 180           VEC_replace (loop_p, SESE_LOOP_NEST (region), i, loop1);
 181           VEC_replace (loop_p, SESE_LOOP_NEST (region), i + 1, loop0);
 182         }
 183     }
 184 }
 185
 186 /* For a USE in BB, if BB is outside REGION, mark the USE in the
 187    LIVEOUTS set.  */
 188
 189 static void
 190 sese_build_liveouts_use (sese region, bitmap liveouts, basic_block bb,
 191                          tree use)
 192 {
 193   unsigned ver;
 194   basic_block def_bb;
 195
 196   if (TREE_CODE (use) != SSA_NAME)
 197     return;
 198
 199   ver = SSA_NAME_VERSION (use);
 200   def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));
 201
 202   if (!def_bb
 203       || !bb_in_sese_p (def_bb, region)
 204       || bb_in_sese_p (bb, region))
 205     return;
 206
 207   bitmap_set_bit (liveouts, ver);
 208 }
 209
 210 /* Marks for rewrite all the SSA_NAMES defined in REGION and that are
 211    used in BB that is outside of the REGION.  */
 212
 213 static void
 214 sese_build_liveouts_bb (sese region, bitmap liveouts, basic_block bb)
 215 {
 216   gimple_stmt_iterator bsi;
 217   edge e;
 218   edge_iterator ei;
 219   ssa_op_iter iter;
 220   use_operand_p use_p;
 221
 222   FOR_EACH_EDGE (e, ei, bb->succs)
 223     for (bsi = gsi_start_phis (e->dest); !gsi_end_p (bsi); gsi_next (&bsi))
 224       sese_build_liveouts_use (region, liveouts, bb,
 225                                PHI_ARG_DEF_FROM_EDGE (gsi_stmt (bsi), e));
 226
 227   for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 228     {
 229       gimple stmt = gsi_stmt (bsi);
 230
 231       if (is_gimple_debug (stmt))
 232         continue;
 233
 234       FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
 235         sese_build_liveouts_use (region, liveouts, bb, USE_FROM_PTR (use_p));
 236     }
 237 }
 238
 239 /* For a USE in BB, return true if BB is outside REGION and it's not
 240    in the LIVEOUTS set.  */
 241
 242 static bool
 243 sese_bad_liveouts_use (sese region, bitmap liveouts, basic_block bb,
 244                        tree use)
 245 {
 246   unsigned ver;
 247   basic_block def_bb;
 248
 249   if (TREE_CODE (use) != SSA_NAME)
 250     return false;
 251
 252   ver = SSA_NAME_VERSION (use);
 253
 254   /* If it's in liveouts, the variable will get a new PHI node, and
 255      the debug use will be properly adjusted.  */
 256   if (bitmap_bit_p (liveouts, ver))
 257     return false;
 258
 259   def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));
 260
 261   if (!def_bb
 262       || !bb_in_sese_p (def_bb, region)
 263       || bb_in_sese_p (bb, region))
 264     return false;
 265
 266   return true;
 267 }
 268
 269 /* Reset debug stmts that reference SSA_NAMES defined in REGION that
 270    are not marked as liveouts.  */
 271
 272 static void
 273 sese_reset_debug_liveouts_bb (sese region, bitmap liveouts, basic_block bb)
 274 {
 275   gimple_stmt_iterator bsi;
 276   ssa_op_iter iter;
 277   use_operand_p use_p;
 278
 279   for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 280     {
 281       gimple stmt = gsi_stmt (bsi);
 282
 283       if (!is_gimple_debug (stmt))
 284         continue;
 285
 286       FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
 287         if (sese_bad_liveouts_use (region, liveouts, bb,
 288                                    USE_FROM_PTR (use_p)))
 289           {
 290             gimple_debug_bind_reset_value (stmt);
 291             update_stmt (stmt);
 292             break;
 293           }
 294     }
 295 }
 296
 297 /* Build the LIVEOUTS of REGION: the set of variables defined inside
 298    and used outside the REGION.  */
 299
 300 static void
 301 sese_build_liveouts (sese region, bitmap liveouts)
 302 {
 303   basic_block bb;
 304
 305   FOR_EACH_BB (bb)
 306     sese_build_liveouts_bb (region, liveouts, bb);
 307   if (MAY_HAVE_DEBUG_INSNS)
 308     FOR_EACH_BB (bb)
 309       sese_reset_debug_liveouts_bb (region, liveouts, bb);
 310 }
 311
 312 /* Builds a new SESE region from edges ENTRY and EXIT.  */
 313
 314 sese
 315 new_sese (edge entry, edge exit)
 316 {
 317   sese region = XNEW (struct sese_s);
 318
 319   SESE_ENTRY (region) = entry;
 320   SESE_EXIT (region) = exit;
 321   SESE_LOOPS (region) = BITMAP_ALLOC (NULL);
 322   SESE_LOOP_NEST (region) = VEC_alloc (loop_p, heap, 3);
 323   SESE_ADD_PARAMS (region) = true;
 324   SESE_PARAMS (region) = VEC_alloc (tree, heap, 3);
 325
 326   return region;
 327 }
 328
 329 /* Deletes REGION.  */
 330
 331 void
 332 free_sese (sese region)
 333 {
 334   if (SESE_LOOPS (region))
 335     SESE_LOOPS (region) = BITMAP_ALLOC (NULL);
 336
 337   VEC_free (tree, heap, SESE_PARAMS (region));
 338   VEC_free (loop_p, heap, SESE_LOOP_NEST (region));
 339
 340   XDELETE (region);
 341 }
 342
 343 /* Add exit phis for USE on EXIT.  */
 344
 345 static void
 346 sese_add_exit_phis_edge (basic_block exit, tree use, edge false_e, edge true_e)
 347 {
 348   gimple phi = create_phi_node (use, exit);
 349
 350   create_new_def_for (gimple_phi_result (phi), phi,
 351                       gimple_phi_result_ptr (phi));
 352   add_phi_arg (phi, use, false_e, UNKNOWN_LOCATION);
 353   add_phi_arg (phi, use, true_e, UNKNOWN_LOCATION);
 354 }
 355
 356 /* Insert in the block BB phi nodes for variables defined in REGION
 357    and used outside the REGION.  The code generation moves REGION in
 358    the else clause of an "if (1)" and generates code in the then
 359    clause that is at this point empty:
 360
 361    | if (1)
 362    |   empty;
 363    | else
 364    |   REGION;
 365 */
 366
 367 void
 368 sese_insert_phis_for_liveouts (sese region, basic_block bb,
 369                                edge false_e, edge true_e)
 370 {
 371   unsigned i;
 372   bitmap_iterator bi;
 373   bitmap liveouts = BITMAP_ALLOC (NULL);
 374
 375   update_ssa (TODO_update_ssa);
 376
 377   sese_build_liveouts (region, liveouts);
 378   EXECUTE_IF_SET_IN_BITMAP (liveouts, 0, i, bi)
 379     sese_add_exit_phis_edge (bb, ssa_name (i), false_e, true_e);
 380   BITMAP_FREE (liveouts);
 381
 382   update_ssa (TODO_update_ssa);
 383 }
 384
 385 /* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag set.  */
 386
 387 edge
 388 get_true_edge_from_guard_bb (basic_block bb)
 389 {
 390   edge e;
 391   edge_iterator ei;
 392
 393   FOR_EACH_EDGE (e, ei, bb->succs)
 394     if (e->flags & EDGE_TRUE_VALUE)
 395       return e;
 396
 397   gcc_unreachable ();
 398   return NULL;
 399 }
 400
 401 /* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag cleared.  */
 402
 403 edge
 404 get_false_edge_from_guard_bb (basic_block bb)
 405 {
 406   edge e;
 407   edge_iterator ei;
 408
 409   FOR_EACH_EDGE (e, ei, bb->succs)
 410     if (!(e->flags & EDGE_TRUE_VALUE))
 411       return e;
 412
 413   gcc_unreachable ();
 414   return NULL;
 415 }
 416
 417 /* Returns the expression associated to OLD_NAME in RENAME_MAP.  */
 418
 419 static tree
 420 get_rename (htab_t rename_map, tree old_name)
 421 {
 422   struct rename_map_elt_s tmp;
 423   PTR *slot;
 424
 425   gcc_assert (TREE_CODE (old_name) == SSA_NAME);
 426   tmp.old_name = old_name;
 427   slot = htab_find_slot (rename_map, &tmp, NO_INSERT);
 428
 429   if (slot && *slot)
 430     return ((rename_map_elt) *slot)->expr;
 431
 432   return NULL_TREE;
 433 }
 434
 435 /* Register in RENAME_MAP the rename tuple (OLD_NAME, EXPR).  */
 436
 437 static void
 438 set_rename (htab_t rename_map, tree old_name, tree expr)
 439 {
 440   struct rename_map_elt_s tmp;
 441   PTR *slot;
 442
 443   if (old_name == expr)
 444     return;
 445
 446   tmp.old_name = old_name;
 447   slot = htab_find_slot (rename_map, &tmp, INSERT);
 448
 449   if (!slot)
 450     return;
 451
 452   if (*slot)
 453     free (*slot);
 454
 455   *slot = new_rename_map_elt (old_name, expr);
 456 }
 457
 458 /* Renames the scalar uses of the statement COPY, using the
 459    substitution map RENAME_MAP, inserting the gimplification code at
 460    GSI_TGT, for the translation REGION, with the original copied
 461    statement in LOOP, and using the induction variable renaming map
 462    IV_MAP.  Returns true when something has been renamed.  */
 463
 464 static bool
 465 rename_uses (gimple copy, htab_t rename_map, gimple_stmt_iterator *gsi_tgt,
 466              sese region, loop_p loop, VEC (tree, heap) *iv_map)
 467 {
 468   use_operand_p use_p;
 469   ssa_op_iter op_iter;
 470   bool changed = false;
 471
 472   if (is_gimple_debug (copy))
 473     {
 474       if (gimple_debug_bind_p (copy))
 475         gimple_debug_bind_reset_value (copy);
 476       else
 477         gcc_unreachable ();
 478
 479       return false;
 480     }
 481
 482   FOR_EACH_SSA_USE_OPERAND (use_p, copy, op_iter, SSA_OP_ALL_USES)
 483     {
 484       tree old_name = USE_FROM_PTR (use_p);
 485       tree new_expr, scev;
 486       gimple_seq stmts;
 487
 488       if (TREE_CODE (old_name) != SSA_NAME
 489           || !is_gimple_reg (old_name)
 490           || SSA_NAME_IS_DEFAULT_DEF (old_name))
 491         continue;
 492
 493       changed = true;
 494       new_expr = get_rename (rename_map, old_name);
 495       if (new_expr)
 496         {
 497           tree type_old_name = TREE_TYPE (old_name);
 498           tree type_new_expr = TREE_TYPE (new_expr);
 499
 500           if (type_old_name != type_new_expr
 501               || (TREE_CODE (new_expr) != SSA_NAME
 502                   && is_gimple_reg (old_name)))
 503             {
 504               tree var = create_tmp_var (type_old_name, "var");
 505
 506               if (type_old_name != type_new_expr)
 507                 new_expr = fold_convert (type_old_name, new_expr);
 508
 509               new_expr = build2 (MODIFY_EXPR, type_old_name, var, new_expr);
 510               new_expr = force_gimple_operand (new_expr, &stmts, true, NULL);
 511               gsi_insert_seq_before (gsi_tgt, stmts, GSI_SAME_STMT);
 512             }
 513
 514           replace_exp (use_p, new_expr);
 515           continue;
 516         }
 517
 518       scev = scalar_evolution_in_region (region, loop, old_name);
 519
 520       /* At this point we should know the exact scev for each
 521          scalar SSA_NAME used in the scop: all the other scalar
 522          SSA_NAMEs should have been translated out of SSA using
 523          arrays with one element.  */
 524       gcc_assert (!chrec_contains_undetermined (scev));
 525
 526       new_expr = chrec_apply_map (scev, iv_map);
 527
 528       /* The apply should produce an expression tree containing
 529          the uses of the new induction variables.  We should be
 530          able to use new_expr instead of the old_name in the newly
 531          generated loop nest.  */
 532       gcc_assert (!chrec_contains_undetermined (new_expr)
 533                   && !tree_contains_chrecs (new_expr, NULL));
 534
 535       /* Replace the old_name with the new_expr.  */
 536       new_expr = force_gimple_operand (unshare_expr (new_expr), &stmts,
 537                                        true, NULL_TREE);
 538       gsi_insert_seq_before (gsi_tgt, stmts, GSI_SAME_STMT);
 539       replace_exp (use_p, new_expr);
 540
 541       if (TREE_CODE (new_expr) == INTEGER_CST
 542           && is_gimple_assign (copy))
 543         {
 544           tree rhs = gimple_assign_rhs1 (copy);
 545
 546           if (TREE_CODE (rhs) == ADDR_EXPR)
 547             recompute_tree_invariant_for_addr_expr (rhs);
 548         }
 549
 550       set_rename (rename_map, old_name, new_expr);
 551     }
 552
 553   return changed;
 554 }
 555
 556 /* Duplicates the statements of basic block BB into basic block NEW_BB
 557    and compute the new induction variables according to the IV_MAP.  */
 558
 559 static void
 560 graphite_copy_stmts_from_block (basic_block bb, basic_block new_bb,
 561                                 htab_t rename_map,
 562                                 VEC (tree, heap) *iv_map, sese region)
 563 {
 564   gimple_stmt_iterator gsi, gsi_tgt;
 565   loop_p loop = bb->loop_father;
 566
 567   gsi_tgt = gsi_start_bb (new_bb);
 568   for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 569     {
 570       def_operand_p def_p;
 571       ssa_op_iter op_iter;
 572       gimple stmt = gsi_stmt (gsi);
 573       gimple copy;
 574       tree lhs;
 575
 576       /* Do not copy labels or conditions.  */
 577       if (gimple_code (stmt) == GIMPLE_LABEL
 578           || gimple_code (stmt) == GIMPLE_COND)
 579         continue;
 580
 581       /* Do not copy induction variables.  */
 582       if (is_gimple_assign (stmt)
 583           && (lhs = gimple_assign_lhs (stmt))
 584           && TREE_CODE (lhs) == SSA_NAME
 585           && is_gimple_reg (lhs)
 586           && scev_analyzable_p (lhs, region))
 587         continue;
 588
 589       /* Create a new copy of STMT and duplicate STMT's virtual
 590          operands.  */
 591       copy = gimple_copy (stmt);
 592       gsi_insert_after (&gsi_tgt, copy, GSI_NEW_STMT);
 593       mark_sym_for_renaming (gimple_vop (cfun));
 594
 595       maybe_duplicate_eh_stmt (copy, stmt);
 596       gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
 597
 598       /* Create new names for all the definitions created by COPY and
 599          add replacement mappings for each new name.  */
 600       FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
 601         {
 602           tree old_name = DEF_FROM_PTR (def_p);
 603           tree new_name = create_new_def_for (old_name, copy, def_p);
 604           set_rename (rename_map, old_name, new_name);
 605         }
 606
 607       if (rename_uses (copy, rename_map, &gsi_tgt, region, loop, iv_map))
 608         fold_stmt_inplace (copy);
 609
 610       update_stmt (copy);
 611     }
 612 }
 613
 614 /* Copies BB and includes in the copied BB all the statements that can
 615    be reached following the use-def chains from the memory accesses,
 616    and returns the next edge following this new block.  */
 617
 618 edge
 619 copy_bb_and_scalar_dependences (basic_block bb, sese region,
 620                                 edge next_e, VEC (tree, heap) *iv_map)
 621 {
 622   basic_block new_bb = split_edge (next_e);
 623   htab_t rename_map = htab_create (10, rename_map_elt_info,
 624                                    eq_rename_map_elts, free);
 625
 626   next_e = single_succ_edge (new_bb);
 627   graphite_copy_stmts_from_block (bb, new_bb, rename_map, iv_map, region);
 628   remove_phi_nodes (new_bb);
 629   htab_delete (rename_map);
 630
 631   return next_e;
 632 }
 633
 634 /* Returns the outermost loop in SCOP that contains BB.  */
 635
 636 struct loop *
 637 outermost_loop_in_sese (sese region, basic_block bb)
 638 {
 639   struct loop *nest;
 640
 641   nest = bb->loop_father;
 642   while (loop_outer (nest)
 643          && loop_in_sese_p (loop_outer (nest), region))
 644     nest = loop_outer (nest);
 645
 646   return nest;
 647 }
 648
 649 /* Sets the false region of an IF_REGION to REGION.  */
 650
 651 void
 652 if_region_set_false_region (ifsese if_region, sese region)
 653 {
 654   basic_block condition = if_region_get_condition_block (if_region);
 655   edge false_edge = get_false_edge_from_guard_bb (condition);
 656   basic_block dummy = false_edge->dest;
 657   edge entry_region = SESE_ENTRY (region);
 658   edge exit_region = SESE_EXIT (region);
 659   basic_block before_region = entry_region->src;
 660   basic_block last_in_region = exit_region->src;
 661   void **slot = htab_find_slot_with_hash (current_loops->exits, exit_region,
 662                                           htab_hash_pointer (exit_region),
 663                                           NO_INSERT);
 664
 665   entry_region->flags = false_edge->flags;
 666   false_edge->flags = exit_region->flags;
 667
 668   redirect_edge_pred (entry_region, condition);
 669   redirect_edge_pred (exit_region, before_region);
 670   redirect_edge_pred (false_edge, last_in_region);
 671   redirect_edge_succ (false_edge, single_succ (dummy));
 672   delete_basic_block (dummy);
 673
 674   exit_region->flags = EDGE_FALLTHRU;
 675   recompute_all_dominators ();
 676
 677   SESE_EXIT (region) = false_edge;
 678
 679   if (if_region->false_region)
 680     free (if_region->false_region);
 681   if_region->false_region = region;
 682
 683   if (slot)
 684     {
 685       struct loop_exit *loop_exit = ggc_alloc_cleared_loop_exit ();
 686
 687       memcpy (loop_exit, *((struct loop_exit **) slot), sizeof (struct loop_exit));
 688       htab_clear_slot (current_loops->exits, slot);
 689
 690       slot = htab_find_slot_with_hash (current_loops->exits, false_edge,
 691                                        htab_hash_pointer (false_edge),
 692                                        INSERT);
 693       loop_exit->e = false_edge;
 694       *slot = loop_exit;
 695       false_edge->src->loop_father->exits->next = loop_exit;
 696     }
 697 }
 698
 699 /* Creates an IFSESE with CONDITION on edge ENTRY.  */
 700
 701 static ifsese
 702 create_if_region_on_edge (edge entry, tree condition)
 703 {
 704   edge e;
 705   edge_iterator ei;
 706   sese sese_region = XNEW (struct sese_s);
 707   sese true_region = XNEW (struct sese_s);
 708   sese false_region = XNEW (struct sese_s);
 709   ifsese if_region = XNEW (struct ifsese_s);
 710   edge exit = create_empty_if_region_on_edge (entry, condition);
 711
 712   if_region->region = sese_region;
 713   if_region->region->entry = entry;
 714   if_region->region->exit = exit;
 715
 716   FOR_EACH_EDGE (e, ei, entry->dest->succs)
 717     {
 718       if (e->flags & EDGE_TRUE_VALUE)
 719         {
 720           true_region->entry = e;
 721           true_region->exit = single_succ_edge (e->dest);
 722           if_region->true_region = true_region;
 723         }
 724       else if (e->flags & EDGE_FALSE_VALUE)
 725         {
 726           false_region->entry = e;
 727           false_region->exit = single_succ_edge (e->dest);
 728           if_region->false_region = false_region;
 729         }
 730     }
 731
 732   return if_region;
 733 }
 734
 735 /* Moves REGION in a condition expression:
 736    | if (1)
 737    |   ;
 738    | else
 739    |   REGION;
 740 */
 741
 742 ifsese
 743 move_sese_in_condition (sese region)
 744 {
 745   basic_block pred_block = split_edge (SESE_ENTRY (region));
 746   ifsese if_region;
 747
 748   SESE_ENTRY (region) = single_succ_edge (pred_block);
 749   if_region = create_if_region_on_edge (single_pred_edge (pred_block), integer_one_node);
 750   if_region_set_false_region (if_region, region);
 751
 752   return if_region;
 753 }
 754
 755 /* Replaces the condition of the IF_REGION with CONDITION:
 756    | if (CONDITION)
 757    |   true_region;
 758    | else
 759    |   false_region;
 760 */
 761
 762 void
 763 set_ifsese_condition (ifsese if_region, tree condition)
 764 {
 765   sese region = if_region->region;
 766   edge entry = region->entry;
 767   basic_block bb = entry->dest;
 768   gimple last = last_stmt (bb);
 769   gimple_stmt_iterator gsi = gsi_last_bb (bb);
 770   gimple cond_stmt;
 771
 772   gcc_assert (gimple_code (last) == GIMPLE_COND);
 773
 774   gsi_remove (&gsi, true);
 775   gsi = gsi_last_bb (bb);
 776   condition = force_gimple_operand_gsi (&gsi, condition, true, NULL,
 777                                         false, GSI_NEW_STMT);
 778   cond_stmt = gimple_build_cond_from_tree (condition, NULL_TREE, NULL_TREE);
 779   gsi = gsi_last_bb (bb);
 780   gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
 781 }
 782
 783 /* Returns the scalar evolution of T in REGION.  Every variable that
 784    is not defined in the REGION is considered a parameter.  */
 785
 786 tree
 787 scalar_evolution_in_region (sese region, loop_p loop, tree t)
 788 {
 789   gimple def;
 790   struct loop *def_loop;
 791   basic_block before = block_before_sese (region);
 792
 793   /* SCOP parameters.  */
 794   if (TREE_CODE (t) == SSA_NAME
 795       && !defined_in_sese_p (t, region))
 796     return t;
 797
 798   if (TREE_CODE (t) != SSA_NAME
 799       || loop_in_sese_p (loop, region))
 800     return instantiate_scev (before, loop,
 801                              analyze_scalar_evolution (loop, t));
 802
 803   def = SSA_NAME_DEF_STMT (t);
 804   def_loop = loop_containing_stmt (def);
 805
 806   if (loop_in_sese_p (def_loop, region))
 807     {
 808       t = analyze_scalar_evolution (def_loop, t);
 809       def_loop = superloop_at_depth (def_loop, loop_depth (loop) + 1);
 810       t = compute_overall_effect_of_inner_loop (def_loop, t);
 811       return t;
 812     }
 813   else
 814     return instantiate_scev (before, loop, t);
 815 }