aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.9/gcc/sese.c
blob: 342c5e864d904be410fb7669925632a245a4e26d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
/* Single entry single exit control flow regions.
   Copyright (C) 2008-2014 Free Software Foundation, Inc.
   Contributed by Jan Sjodin <jan.sjodin@amd.com> and
   Sebastian Pop <sebastian.pop@amd.com>.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "hash-table.h"
#include "tree.h"
#include "tree-pretty-print.h"
#include "basic-block.h"
#include "tree-ssa-alias.h"
#include "internal-fn.h"
#include "gimple-fold.h"
#include "tree-eh.h"
#include "gimple-expr.h"
#include "is-a.h"
#include "gimple.h"
#include "gimplify.h"
#include "gimple-iterator.h"
#include "gimplify-me.h"
#include "gimple-ssa.h"
#include "tree-cfg.h"
#include "tree-phinodes.h"
#include "ssa-iterators.h"
#include "stringpool.h"
#include "tree-ssanames.h"
#include "tree-ssa-loop.h"
#include "tree-into-ssa.h"
#include "cfgloop.h"
#include "tree-chrec.h"
#include "tree-data-ref.h"
#include "tree-scalar-evolution.h"
#include "tree-pass.h"
#include "value-prof.h"
#include "sese.h"
#include "tree-ssa-propagate.h"

/* Print to stderr the element ELT.  */

static void
debug_rename_elt (rename_map_elt elt)
{
  fprintf (stderr, "(");
  print_generic_expr (stderr, elt->old_name, 0);
  fprintf (stderr, ", ");
  print_generic_expr (stderr, elt->expr, 0);
  fprintf (stderr, ")\n");
}

/* Helper function for debug_rename_map.  */

int
debug_rename_map_1 (rename_map_elt_s **slot, void *s ATTRIBUTE_UNUSED)
{
  struct rename_map_elt_s *entry = *slot;
  debug_rename_elt (entry);
  return 1;
}


/* Hashtable helpers.  */

struct rename_map_hasher : typed_free_remove <rename_map_elt_s>
{
  typedef rename_map_elt_s value_type;
  typedef rename_map_elt_s compare_type;
  static inline hashval_t hash (const value_type *);
  static inline bool equal (const value_type *, const compare_type *);
};

/* Computes a hash function for database element ELT.  */

inline hashval_t
rename_map_hasher::hash (const value_type *elt)
{
  return SSA_NAME_VERSION (elt->old_name);
}

/* Compares database elements E1 and E2.  */

inline bool
rename_map_hasher::equal (const value_type *elt1, const compare_type *elt2)
{
  return (elt1->old_name == elt2->old_name);
}

typedef hash_table <rename_map_hasher> rename_map_type;


/* Print to stderr all the elements of RENAME_MAP.  */

DEBUG_FUNCTION void
debug_rename_map (rename_map_type rename_map)
{
  rename_map.traverse <void *, debug_rename_map_1> (NULL);
}

/* Computes a hash function for database element ELT.  */

hashval_t
rename_map_elt_info (const void *elt)
{
  return SSA_NAME_VERSION (((const struct rename_map_elt_s *) elt)->old_name);
}

/* Compares database elements E1 and E2.  */

int
eq_rename_map_elts (const void *e1, const void *e2)
{
  const struct rename_map_elt_s *elt1 = (const struct rename_map_elt_s *) e1;
  const struct rename_map_elt_s *elt2 = (const struct rename_map_elt_s *) e2;

  return (elt1->old_name == elt2->old_name);
}



/* Record LOOP as occurring in REGION.  */

static void
sese_record_loop (sese region, loop_p loop)
{
  if (sese_contains_loop (region, loop))
    return;

  bitmap_set_bit (SESE_LOOPS (region), loop->num);
  SESE_LOOP_NEST (region).safe_push (loop);
}

/* Build the loop nests contained in REGION.  Returns true when the
   operation was successful.  */

void
build_sese_loop_nests (sese region)
{
  unsigned i;
  basic_block bb;
  struct loop *loop0, *loop1;

  FOR_EACH_BB_FN (bb, cfun)
    if (bb_in_sese_p (bb, region))
      {
	struct loop *loop = bb->loop_father;

	/* Only add loops if they are completely contained in the SCoP.  */
	if (loop->header == bb
	    && bb_in_sese_p (loop->latch, region))
	  sese_record_loop (region, loop);
      }

  /* Make sure that the loops in the SESE_LOOP_NEST are ordered.  It
     can be the case that an inner loop is inserted before an outer
     loop.  To avoid this, semi-sort once.  */
  FOR_EACH_VEC_ELT (SESE_LOOP_NEST (region), i, loop0)
    {
      if (SESE_LOOP_NEST (region).length () == i + 1)
	break;

      loop1 = SESE_LOOP_NEST (region)[i + 1];
      if (loop0->num > loop1->num)
	{
	  SESE_LOOP_NEST (region)[i] = loop1;
	  SESE_LOOP_NEST (region)[i + 1] = loop0;
	}
    }
}

/* For a USE in BB, if BB is outside REGION, mark the USE in the
   LIVEOUTS set.  */

static void
sese_build_liveouts_use (sese region, bitmap liveouts, basic_block bb,
			 tree use)
{
  unsigned ver;
  basic_block def_bb;

  if (TREE_CODE (use) != SSA_NAME)
    return;

  ver = SSA_NAME_VERSION (use);
  def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));

  if (!def_bb
      || !bb_in_sese_p (def_bb, region)
      || bb_in_sese_p (bb, region))
    return;

  bitmap_set_bit (liveouts, ver);
}

/* Marks for rewrite all the SSA_NAMES defined in REGION and that are
   used in BB that is outside of the REGION.  */

static void
sese_build_liveouts_bb (sese region, bitmap liveouts, basic_block bb)
{
  gimple_stmt_iterator bsi;
  edge e;
  edge_iterator ei;
  ssa_op_iter iter;
  use_operand_p use_p;

  FOR_EACH_EDGE (e, ei, bb->succs)
    for (bsi = gsi_start_phis (e->dest); !gsi_end_p (bsi); gsi_next (&bsi))
      sese_build_liveouts_use (region, liveouts, bb,
			       PHI_ARG_DEF_FROM_EDGE (gsi_stmt (bsi), e));

  for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
    {
      gimple stmt = gsi_stmt (bsi);

      if (is_gimple_debug (stmt))
	continue;

      FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
	sese_build_liveouts_use (region, liveouts, bb, USE_FROM_PTR (use_p));
    }
}

/* For a USE in BB, return true if BB is outside REGION and it's not
   in the LIVEOUTS set.  */

static bool
sese_bad_liveouts_use (sese region, bitmap liveouts, basic_block bb,
		       tree use)
{
  unsigned ver;
  basic_block def_bb;

  if (TREE_CODE (use) != SSA_NAME)
    return false;

  ver = SSA_NAME_VERSION (use);

  /* If it's in liveouts, the variable will get a new PHI node, and
     the debug use will be properly adjusted.  */
  if (bitmap_bit_p (liveouts, ver))
    return false;

  def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));

  if (!def_bb
      || !bb_in_sese_p (def_bb, region)
      || bb_in_sese_p (bb, region))
    return false;

  return true;
}

/* Reset debug stmts that reference SSA_NAMES defined in REGION that
   are not marked as liveouts.  */

static void
sese_reset_debug_liveouts_bb (sese region, bitmap liveouts, basic_block bb)
{
  gimple_stmt_iterator bsi;
  ssa_op_iter iter;
  use_operand_p use_p;

  for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
    {
      gimple stmt = gsi_stmt (bsi);

      if (!is_gimple_debug (stmt))
	continue;

      FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
	if (sese_bad_liveouts_use (region, liveouts, bb,
				   USE_FROM_PTR (use_p)))
	  {
	    gimple_debug_bind_reset_value (stmt);
	    update_stmt (stmt);
	    break;
	  }
    }
}

/* Build the LIVEOUTS of REGION: the set of variables defined inside
   and used outside the REGION.  */

static void
sese_build_liveouts (sese region, bitmap liveouts)
{
  basic_block bb;

  FOR_EACH_BB_FN (bb, cfun)
    sese_build_liveouts_bb (region, liveouts, bb);
  if (MAY_HAVE_DEBUG_STMTS)
    FOR_EACH_BB_FN (bb, cfun)
      sese_reset_debug_liveouts_bb (region, liveouts, bb);
}

/* Builds a new SESE region from edges ENTRY and EXIT.  */

sese
new_sese (edge entry, edge exit)
{
  sese region = XNEW (struct sese_s);

  SESE_ENTRY (region) = entry;
  SESE_EXIT (region) = exit;
  SESE_LOOPS (region) = BITMAP_ALLOC (NULL);
  SESE_LOOP_NEST (region).create (3);
  SESE_ADD_PARAMS (region) = true;
  SESE_PARAMS (region).create (3);

  return region;
}

/* Deletes REGION.  */

void
free_sese (sese region)
{
  if (SESE_LOOPS (region))
    SESE_LOOPS (region) = BITMAP_ALLOC (NULL);

  SESE_PARAMS (region).release ();
  SESE_LOOP_NEST (region).release ();

  XDELETE (region);
}

/* Add exit phis for USE on EXIT.  */

static void
sese_add_exit_phis_edge (basic_block exit, tree use, edge false_e, edge true_e)
{
  gimple phi = create_phi_node (NULL_TREE, exit);
  create_new_def_for (use, phi, gimple_phi_result_ptr (phi));
  add_phi_arg (phi, use, false_e, UNKNOWN_LOCATION);
  add_phi_arg (phi, use, true_e, UNKNOWN_LOCATION);
}

/* Insert in the block BB phi nodes for variables defined in REGION
   and used outside the REGION.  The code generation moves REGION in
   the else clause of an "if (1)" and generates code in the then
   clause that is at this point empty:

   | if (1)
   |   empty;
   | else
   |   REGION;
*/

void
sese_insert_phis_for_liveouts (sese region, basic_block bb,
			       edge false_e, edge true_e)
{
  unsigned i;
  bitmap_iterator bi;
  bitmap liveouts = BITMAP_ALLOC (NULL);

  update_ssa (TODO_update_ssa);

  sese_build_liveouts (region, liveouts);
  EXECUTE_IF_SET_IN_BITMAP (liveouts, 0, i, bi)
    sese_add_exit_phis_edge (bb, ssa_name (i), false_e, true_e);
  BITMAP_FREE (liveouts);

  update_ssa (TODO_update_ssa);
}

/* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag set.  */

edge
get_true_edge_from_guard_bb (basic_block bb)
{
  edge e;
  edge_iterator ei;

  FOR_EACH_EDGE (e, ei, bb->succs)
    if (e->flags & EDGE_TRUE_VALUE)
      return e;

  gcc_unreachable ();
  return NULL;
}

/* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag cleared.  */

edge
get_false_edge_from_guard_bb (basic_block bb)
{
  edge e;
  edge_iterator ei;

  FOR_EACH_EDGE (e, ei, bb->succs)
    if (!(e->flags & EDGE_TRUE_VALUE))
      return e;

  gcc_unreachable ();
  return NULL;
}

/* Returns the expression associated to OLD_NAME in RENAME_MAP.  */

static tree
get_rename (rename_map_type rename_map, tree old_name)
{
  struct rename_map_elt_s tmp;
  rename_map_elt_s **slot;

  gcc_assert (TREE_CODE (old_name) == SSA_NAME);
  tmp.old_name = old_name;
  slot = rename_map.find_slot (&tmp, NO_INSERT);

  if (slot && *slot)
    return (*slot)->expr;

  return NULL_TREE;
}

/* Register in RENAME_MAP the rename tuple (OLD_NAME, EXPR).  */

static void
set_rename (rename_map_type rename_map, tree old_name, tree expr)
{
  struct rename_map_elt_s tmp;
  rename_map_elt_s **slot;

  if (old_name == expr)
    return;

  tmp.old_name = old_name;
  slot = rename_map.find_slot (&tmp, INSERT);

  if (!slot)
    return;

  free (*slot);

  *slot = new_rename_map_elt (old_name, expr);
}

/* Renames the scalar uses of the statement COPY, using the
   substitution map RENAME_MAP, inserting the gimplification code at
   GSI_TGT, for the translation REGION, with the original copied
   statement in LOOP, and using the induction variable renaming map
   IV_MAP.  Returns true when something has been renamed.  GLOOG_ERROR
   is set when the code generation cannot continue.  */

static bool
rename_uses (gimple copy, rename_map_type rename_map,
	     gimple_stmt_iterator *gsi_tgt,
	     sese region, loop_p loop, vec<tree> iv_map,
	     bool *gloog_error)
{
  use_operand_p use_p;
  ssa_op_iter op_iter;
  bool changed = false;

  if (is_gimple_debug (copy))
    {
      if (gimple_debug_bind_p (copy))
	gimple_debug_bind_reset_value (copy);
      else if (gimple_debug_source_bind_p (copy))
	return false;
      else
	gcc_unreachable ();

      return false;
    }

  FOR_EACH_SSA_USE_OPERAND (use_p, copy, op_iter, SSA_OP_USE)
    {
      tree old_name = USE_FROM_PTR (use_p);
      tree new_expr, scev;
      gimple_seq stmts;

      if (TREE_CODE (old_name) != SSA_NAME
	  || SSA_NAME_IS_DEFAULT_DEF (old_name))
	continue;

      changed = true;
      new_expr = get_rename (rename_map, old_name);
      if (new_expr)
	{
	  tree type_old_name = TREE_TYPE (old_name);
	  tree type_new_expr = TREE_TYPE (new_expr);

	  if (type_old_name != type_new_expr
	      || TREE_CODE (new_expr) != SSA_NAME)
	    {
	      tree var = create_tmp_var (type_old_name, "var");

	      if (!useless_type_conversion_p (type_old_name, type_new_expr))
		new_expr = fold_convert (type_old_name, new_expr);

	      new_expr = force_gimple_operand (new_expr, &stmts, true, var);
	      gsi_insert_seq_before (gsi_tgt, stmts, GSI_SAME_STMT);
	    }

	  replace_exp (use_p, new_expr);
	  continue;
	}

      scev = scalar_evolution_in_region (region, loop, old_name);

      /* At this point we should know the exact scev for each
	 scalar SSA_NAME used in the scop: all the other scalar
	 SSA_NAMEs should have been translated out of SSA using
	 arrays with one element.  */
      if (chrec_contains_undetermined (scev))
	{
	  *gloog_error = true;
	  new_expr = build_zero_cst (TREE_TYPE (old_name));
	}
      else
	new_expr = chrec_apply_map (scev, iv_map);

      /* The apply should produce an expression tree containing
	 the uses of the new induction variables.  We should be
	 able to use new_expr instead of the old_name in the newly
	 generated loop nest.  */
      if (chrec_contains_undetermined (new_expr)
	  || tree_contains_chrecs (new_expr, NULL))
	{
	  *gloog_error = true;
	  new_expr = build_zero_cst (TREE_TYPE (old_name));
	}
      else
	/* Replace the old_name with the new_expr.  */
	new_expr = force_gimple_operand (unshare_expr (new_expr), &stmts,
					 true, NULL_TREE);

      gsi_insert_seq_before (gsi_tgt, stmts, GSI_SAME_STMT);
      replace_exp (use_p, new_expr);

      if (TREE_CODE (new_expr) == INTEGER_CST
	  && is_gimple_assign (copy))
	{
	  tree rhs = gimple_assign_rhs1 (copy);

	  if (TREE_CODE (rhs) == ADDR_EXPR)
	    recompute_tree_invariant_for_addr_expr (rhs);
	}

      set_rename (rename_map, old_name, new_expr);
    }

  return changed;
}

/* Duplicates the statements of basic block BB into basic block NEW_BB
   and compute the new induction variables according to the IV_MAP.
   GLOOG_ERROR is set when the code generation cannot continue.  */

static void
graphite_copy_stmts_from_block (basic_block bb, basic_block new_bb,
				rename_map_type rename_map,
				vec<tree> iv_map, sese region,
				bool *gloog_error)
{
  gimple_stmt_iterator gsi, gsi_tgt;
  loop_p loop = bb->loop_father;

  gsi_tgt = gsi_start_bb (new_bb);
  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      def_operand_p def_p;
      ssa_op_iter op_iter;
      gimple stmt = gsi_stmt (gsi);
      gimple copy;
      tree lhs;

      /* Do not copy labels or conditions.  */
      if (gimple_code (stmt) == GIMPLE_LABEL
	  || gimple_code (stmt) == GIMPLE_COND)
	continue;

      /* Do not copy induction variables.  */
      if (is_gimple_assign (stmt)
	  && (lhs = gimple_assign_lhs (stmt))
	  && TREE_CODE (lhs) == SSA_NAME
	  && is_gimple_reg (lhs)
	  && scev_analyzable_p (lhs, region))
	continue;

      /* Create a new copy of STMT and duplicate STMT's virtual
	 operands.  */
      copy = gimple_copy (stmt);
      gsi_insert_after (&gsi_tgt, copy, GSI_NEW_STMT);

      maybe_duplicate_eh_stmt (copy, stmt);
      gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);

      /* Create new names for all the definitions created by COPY and
	 add replacement mappings for each new name.  */
      FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
 	{
 	  tree old_name = DEF_FROM_PTR (def_p);
 	  tree new_name = create_new_def_for (old_name, copy, def_p);
	  set_rename (rename_map, old_name, new_name);
 	}

      if (rename_uses (copy, rename_map, &gsi_tgt, region, loop, iv_map,
		       gloog_error))
	{
	  gcc_assert (gsi_stmt (gsi_tgt) == copy);
	  fold_stmt_inplace (&gsi_tgt);
	}

      update_stmt (copy);
    }
}

/* Copies BB and includes in the copied BB all the statements that can
   be reached following the use-def chains from the memory accesses,
   and returns the next edge following this new block.  GLOOG_ERROR is
   set when the code generation cannot continue.  */

edge
copy_bb_and_scalar_dependences (basic_block bb, sese region,
				edge next_e, vec<tree> iv_map,
				bool *gloog_error)
{
  basic_block new_bb = split_edge (next_e);
  rename_map_type rename_map;
  rename_map.create (10);

  next_e = single_succ_edge (new_bb);
  graphite_copy_stmts_from_block (bb, new_bb, rename_map, iv_map, region,
				  gloog_error);
  remove_phi_nodes (new_bb);
  rename_map.dispose ();

  return next_e;
}

/* Returns the outermost loop in SCOP that contains BB.  */

struct loop *
outermost_loop_in_sese (sese region, basic_block bb)
{
  struct loop *nest;

  nest = bb->loop_father;
  while (loop_outer (nest)
	 && loop_in_sese_p (loop_outer (nest), region))
    nest = loop_outer (nest);

  return nest;
}

/* Sets the false region of an IF_REGION to REGION.  */

void
if_region_set_false_region (ifsese if_region, sese region)
{
  basic_block condition = if_region_get_condition_block (if_region);
  edge false_edge = get_false_edge_from_guard_bb (condition);
  basic_block dummy = false_edge->dest;
  edge entry_region = SESE_ENTRY (region);
  edge exit_region = SESE_EXIT (region);
  basic_block before_region = entry_region->src;
  basic_block last_in_region = exit_region->src;
  void **slot = htab_find_slot_with_hash (current_loops->exits, exit_region,
					  htab_hash_pointer (exit_region),
					  NO_INSERT);

  entry_region->flags = false_edge->flags;
  false_edge->flags = exit_region->flags;

  redirect_edge_pred (entry_region, condition);
  redirect_edge_pred (exit_region, before_region);
  redirect_edge_pred (false_edge, last_in_region);
  redirect_edge_succ (false_edge, single_succ (dummy));
  delete_basic_block (dummy);

  exit_region->flags = EDGE_FALLTHRU;
  recompute_all_dominators ();

  SESE_EXIT (region) = false_edge;

  free (if_region->false_region);
  if_region->false_region = region;

  if (slot)
    {
      struct loop_exit *loop_exit = ggc_alloc_cleared_loop_exit ();

      memcpy (loop_exit, *((struct loop_exit **) slot), sizeof (struct loop_exit));
      htab_clear_slot (current_loops->exits, slot);

      slot = htab_find_slot_with_hash (current_loops->exits, false_edge,
				       htab_hash_pointer (false_edge),
				       INSERT);
      loop_exit->e = false_edge;
      *slot = loop_exit;
      false_edge->src->loop_father->exits->next = loop_exit;
    }
}

/* Creates an IFSESE with CONDITION on edge ENTRY.  */

static ifsese
create_if_region_on_edge (edge entry, tree condition)
{
  edge e;
  edge_iterator ei;
  sese sese_region = XNEW (struct sese_s);
  sese true_region = XNEW (struct sese_s);
  sese false_region = XNEW (struct sese_s);
  ifsese if_region = XNEW (struct ifsese_s);
  edge exit = create_empty_if_region_on_edge (entry, condition);

  if_region->region = sese_region;
  if_region->region->entry = entry;
  if_region->region->exit = exit;

  FOR_EACH_EDGE (e, ei, entry->dest->succs)
    {
      if (e->flags & EDGE_TRUE_VALUE)
	{
	  true_region->entry = e;
	  true_region->exit = single_succ_edge (e->dest);
	  if_region->true_region = true_region;
	}
      else if (e->flags & EDGE_FALSE_VALUE)
	{
	  false_region->entry = e;
	  false_region->exit = single_succ_edge (e->dest);
	  if_region->false_region = false_region;
	}
    }

  return if_region;
}

/* Moves REGION in a condition expression:
   | if (1)
   |   ;
   | else
   |   REGION;
*/

ifsese
move_sese_in_condition (sese region)
{
  basic_block pred_block = split_edge (SESE_ENTRY (region));
  ifsese if_region;

  SESE_ENTRY (region) = single_succ_edge (pred_block);
  if_region = create_if_region_on_edge (single_pred_edge (pred_block), integer_one_node);
  if_region_set_false_region (if_region, region);

  return if_region;
}

/* Replaces the condition of the IF_REGION with CONDITION:
   | if (CONDITION)
   |   true_region;
   | else
   |   false_region;
*/

void
set_ifsese_condition (ifsese if_region, tree condition)
{
  sese region = if_region->region;
  edge entry = region->entry;
  basic_block bb = entry->dest;
  gimple last = last_stmt (bb);
  gimple_stmt_iterator gsi = gsi_last_bb (bb);
  gimple cond_stmt;

  gcc_assert (gimple_code (last) == GIMPLE_COND);

  gsi_remove (&gsi, true);
  gsi = gsi_last_bb (bb);
  condition = force_gimple_operand_gsi (&gsi, condition, true, NULL,
					false, GSI_NEW_STMT);
  cond_stmt = gimple_build_cond_from_tree (condition, NULL_TREE, NULL_TREE);
  gsi = gsi_last_bb (bb);
  gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
}

/* Returns the scalar evolution of T in REGION.  Every variable that
   is not defined in the REGION is considered a parameter.  */

tree
scalar_evolution_in_region (sese region, loop_p loop, tree t)
{
  gimple def;
  struct loop *def_loop;
  basic_block before = block_before_sese (region);

  /* SCOP parameters.  */
  if (TREE_CODE (t) == SSA_NAME
      && !defined_in_sese_p (t, region))
    return t;

  if (TREE_CODE (t) != SSA_NAME
      || loop_in_sese_p (loop, region))
    return instantiate_scev (before, loop,
			     analyze_scalar_evolution (loop, t));

  def = SSA_NAME_DEF_STMT (t);
  def_loop = loop_containing_stmt (def);

  if (loop_in_sese_p (def_loop, region))
    {
      t = analyze_scalar_evolution (def_loop, t);
      def_loop = superloop_at_depth (def_loop, loop_depth (loop) + 1);
      t = compute_overall_effect_of_inner_loop (def_loop, t);
      return t;
    }
  else
    return instantiate_scev (before, loop, t);
}