gcc/gimple-iterator.c

   1 /* Iterator routines for GIMPLE statements.
   2    Copyright (C) 2007, 2008 Free Software Foundation, Inc.
   3    Contributed by Aldy Hernandez  <aldy@quesejoda.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "tree-flow.h"
  28 #include "value-prof.h"
  29
  30
  31 /* Mark the statement STMT as modified, and update it.  */
  32
  33 static inline void
  34 update_modified_stmt (gimple stmt)
  35 {
  36   if (!ssa_operands_active ())
  37     return;
  38   update_stmt_if_modified (stmt);
  39 }
  40
  41
  42 /* Mark the statements in SEQ as modified, and update them.  */
  43
  44 static void
  45 update_modified_stmts (gimple_seq seq)
  46 {
  47   gimple_stmt_iterator gsi;
  48
  49   if (!ssa_operands_active ())
  50     return;
  51   for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
  52     update_stmt_if_modified (gsi_stmt (gsi));
  53 }
  54
  55
  56 /* Set BB to be the basic block for all the statements in the list
  57    starting at FIRST and LAST.  */
  58
  59 static void
  60 update_bb_for_stmts (gimple_seq_node first, basic_block bb)
  61 {
  62   gimple_seq_node n;
  63
  64   for (n = first; n; n = n->next)
  65     gimple_set_bb (n->stmt, bb);
  66 }
  67
  68
  69 /* Insert the sequence delimited by nodes FIRST and LAST before
  70    iterator I.  M specifies how to update iterator I after insertion
  71    (see enum gsi_iterator_update).
  72
  73    This routine assumes that there is a forward and backward path
  74    between FIRST and LAST (i.e., they are linked in a doubly-linked
  75    list).  Additionally, if FIRST == LAST, this routine will properly
  76    insert a single node.  */
  77
  78 static void
  79 gsi_insert_seq_nodes_before (gimple_stmt_iterator *i,
  80                              gimple_seq_node first,
  81                              gimple_seq_node last,
  82                              enum gsi_iterator_update mode)
  83 {
  84   basic_block bb;
  85   gimple_seq_node cur = i->ptr;
  86
  87   if ((bb = gsi_bb (*i)) != NULL)
  88     update_bb_for_stmts (first, bb);
  89
  90   /* Link SEQ before CUR in the sequence.  */
  91   if (cur)
  92     {
  93       first->prev = cur->prev;
  94       if (first->prev)
  95         first->prev->next = first;
  96       else
  97         gimple_seq_set_first (i->seq, first);
  98       last->next = cur;
  99       cur->prev = last;
 100     }
 101   else
 102     {
 103       gimple_seq_node itlast = gimple_seq_last (i->seq);
 104
 105       /* If CUR is NULL, we link at the end of the sequence (this case happens
 106          when gsi_after_labels is called for a basic block that contains only
 107          labels, so it returns an iterator after the end of the block, and
 108          we need to insert before it; it might be cleaner to add a flag to the
 109          iterator saying whether we are at the start or end of the list).  */
 110       first->prev = itlast;
 111       if (itlast)
 112         itlast->next = first;
 113       else
 114         gimple_seq_set_first (i->seq, first);
 115       gimple_seq_set_last (i->seq, last);
 116     }
 117
 118   /* Update the iterator, if requested.  */
 119   switch (mode)
 120     {
 121     case GSI_NEW_STMT:
 122     case GSI_CONTINUE_LINKING:
 123       i->ptr = first;
 124       break;
 125     case GSI_SAME_STMT:
 126       break;
 127     default:
 128       gcc_unreachable ();
 129     }
 130 }
 131
 132
 133 /* Inserts the sequence of statements SEQ before the statement pointed
 134    by iterator I.  MODE indicates what to do with the iterator after
 135    insertion (see enum gsi_iterator_update).
 136
 137    This function does not scan for new operands.  It is provided for
 138    the use of the gimplifier, which manipulates statements for which
 139    def/use information has not yet been constructed.  Most callers
 140    should use gsi_insert_seq_before.  */
 141
 142 void
 143 gsi_insert_seq_before_without_update (gimple_stmt_iterator *i, gimple_seq seq,
 144                                       enum gsi_iterator_update mode)
 145 {
 146   gimple_seq_node first, last;
 147
 148   if (seq == NULL)
 149     return;
 150
 151   /* Don't allow inserting a sequence into itself.  */
 152   gcc_assert (seq != i->seq);
 153
 154   first = gimple_seq_first (seq);
 155   last = gimple_seq_last (seq);
 156
 157   gimple_seq_set_first (seq, NULL);
 158   gimple_seq_set_last (seq, NULL);
 159   gimple_seq_free (seq);
 160
 161   /* Empty sequences need no work.  */
 162   if (!first || !last)
 163     {
 164       gcc_assert (first == last);
 165       return;
 166     }
 167
 168   gsi_insert_seq_nodes_before (i, first, last, mode);
 169 }
 170
 171
 172 /* Inserts the sequence of statements SEQ before the statement pointed
 173    by iterator I.  MODE indicates what to do with the iterator after
 174    insertion (see enum gsi_iterator_update). Scan the statements in SEQ
 175    for new operands.  */
 176
 177 void
 178 gsi_insert_seq_before (gimple_stmt_iterator *i, gimple_seq seq,
 179                        enum gsi_iterator_update mode)
 180 {
 181   update_modified_stmts (seq);
 182   gsi_insert_seq_before_without_update (i, seq, mode);
 183 }
 184
 185
 186 /* Insert the sequence delimited by nodes FIRST and LAST after
 187    iterator I.  M specifies how to update iterator I after insertion
 188    (see enum gsi_iterator_update).
 189
 190    This routine assumes that there is a forward and backward path
 191    between FIRST and LAST (i.e., they are linked in a doubly-linked
 192    list).  Additionally, if FIRST == LAST, this routine will properly
 193    insert a single node.  */
 194
 195 static void
 196 gsi_insert_seq_nodes_after (gimple_stmt_iterator *i,
 197                             gimple_seq_node first,
 198                             gimple_seq_node last,
 199                             enum gsi_iterator_update m)
 200 {
 201   basic_block bb;
 202   gimple_seq_node cur = i->ptr;
 203
 204   /* If the iterator is inside a basic block, we need to update the
 205      basic block information for all the nodes between FIRST and LAST.  */
 206   if ((bb = gsi_bb (*i)) != NULL)
 207     update_bb_for_stmts (first, bb);
 208
 209   /* Link SEQ after CUR.  */
 210   if (cur)
 211     {
 212       last->next = cur->next;
 213       if (last->next)
 214         last->next->prev = last;
 215       else
 216         gimple_seq_set_last (i->seq, last);
 217       first->prev = cur;
 218       cur->next = first;
 219     }
 220   else
 221     {
 222       gcc_assert (!gimple_seq_last (i->seq));
 223       gimple_seq_set_first (i->seq, first);
 224       gimple_seq_set_last (i->seq, last);
 225     }
 226
 227   /* Update the iterator, if requested.  */
 228   switch (m)
 229     {
 230     case GSI_NEW_STMT:
 231       i->ptr = first;
 232       break;
 233     case GSI_CONTINUE_LINKING:
 234       i->ptr = last;
 235       break;
 236     case GSI_SAME_STMT:
 237       gcc_assert (cur);
 238       break;
 239     default:
 240       gcc_unreachable ();
 241     }
 242 }
 243
 244
 245 /* Links sequence SEQ after the statement pointed-to by iterator I.
 246    MODE is as in gsi_insert_after.
 247
 248    This function does not scan for new operands.  It is provided for
 249    the use of the gimplifier, which manipulates statements for which
 250    def/use information has not yet been constructed.  Most callers
 251    should use gsi_insert_seq_after.  */
 252
 253 void
 254 gsi_insert_seq_after_without_update (gimple_stmt_iterator *i, gimple_seq seq,
 255                                      enum gsi_iterator_update mode)
 256 {
 257   gimple_seq_node first, last;
 258
 259   if (seq == NULL)
 260     return;
 261
 262   /* Don't allow inserting a sequence into itself.  */
 263   gcc_assert (seq != i->seq);
 264
 265   first = gimple_seq_first (seq);
 266   last = gimple_seq_last (seq);
 267
 268   gimple_seq_set_first (seq, NULL);
 269   gimple_seq_set_last (seq, NULL);
 270   gimple_seq_free (seq);
 271
 272   /* Empty sequences need no work.  */
 273   if (!first || !last)
 274     {
 275       gcc_assert (first == last);
 276       return;
 277     }
 278
 279   gsi_insert_seq_nodes_after (i, first, last, mode);
 280 }
 281
 282
 283 /* Links sequence SEQ after the statement pointed-to by iterator I.
 284    MODE is as in gsi_insert_after.  Scan the statements in SEQ
 285    for new operands.  */
 286
 287 void
 288 gsi_insert_seq_after (gimple_stmt_iterator *i, gimple_seq seq,
 289                       enum gsi_iterator_update mode)
 290 {
 291   update_modified_stmts (seq);
 292   gsi_insert_seq_after_without_update (i, seq, mode);
 293 }
 294
 295
 296 /* Move all statements in the sequence after I to a new sequence.
 297    Return this new sequence.  */
 298
 299 gimple_seq
 300 gsi_split_seq_after (gimple_stmt_iterator i)
 301 {
 302   gimple_seq_node cur, next;
 303   gimple_seq old_seq, new_seq;
 304
 305   cur = i.ptr;
 306
 307   /* How can we possibly split after the end, or before the beginning?  */
 308   gcc_assert (cur && cur->next);
 309   next = cur->next;
 310
 311   old_seq = i.seq;
 312   new_seq = gimple_seq_alloc ();
 313
 314   gimple_seq_set_first (new_seq, next);
 315   gimple_seq_set_last (new_seq, gimple_seq_last (old_seq));
 316   gimple_seq_set_last (old_seq, cur);
 317   cur->next = NULL;
 318   next->prev = NULL;
 319
 320   return new_seq;
 321 }
 322
 323
 324 /* Move all statements in the sequence before I to a new sequence.
 325    Return this new sequence.  I is set to the head of the new list.  */
 326
 327 gimple_seq
 328 gsi_split_seq_before (gimple_stmt_iterator *i)
 329 {
 330   gimple_seq_node cur, prev;
 331   gimple_seq old_seq, new_seq;
 332
 333   cur = i->ptr;
 334
 335   /* How can we possibly split after the end?  */
 336   gcc_assert (cur);
 337   prev = cur->prev;
 338
 339   old_seq = i->seq;
 340   new_seq = gimple_seq_alloc ();
 341   i->seq = new_seq;
 342
 343   /* Set the limits on NEW_SEQ.  */
 344   gimple_seq_set_first (new_seq, cur);
 345   gimple_seq_set_last (new_seq, gimple_seq_last (old_seq));
 346
 347   /* Cut OLD_SEQ before I.  */
 348   gimple_seq_set_last (old_seq, prev);
 349   cur->prev = NULL;
 350   if (prev)
 351     prev->next = NULL;
 352   else
 353     gimple_seq_set_first (old_seq, NULL);
 354
 355   return new_seq;
 356 }
 357
 358
 359 /* Replace the statement pointed-to by GSI to STMT.  If UPDATE_EH_INFO
 360    is true, the exception handling information of the original
 361    statement is moved to the new statement.  */
 362
 363 void
 364 gsi_replace (gimple_stmt_iterator *gsi, gimple stmt, bool update_eh_info)
 365 {
 366   gimple orig_stmt = gsi_stmt (*gsi);
 367
 368   if (stmt == orig_stmt)
 369     return;
 370
 371   gimple_set_location (stmt, gimple_location (orig_stmt));
 372   gimple_set_bb (stmt, gsi_bb (*gsi));
 373
 374   /* Preserve EH region information from the original statement, if
 375      requested by the caller.  */
 376   if (update_eh_info)
 377     maybe_clean_or_replace_eh_stmt (orig_stmt, stmt);
 378
 379   gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
 380   gimple_remove_stmt_histograms (cfun, orig_stmt);
 381   delink_stmt_imm_use (orig_stmt);
 382   *gsi_stmt_ptr (gsi) = stmt;
 383   gimple_set_modified (stmt, true);
 384   update_modified_stmt (stmt);
 385 }
 386
 387
 388 /* Insert statement STMT before the statement pointed-to by iterator I.
 389    M specifies how to update iterator I after insertion (see enum
 390    gsi_iterator_update).
 391
 392    This function does not scan for new operands.  It is provided for
 393    the use of the gimplifier, which manipulates statements for which
 394    def/use information has not yet been constructed.  Most callers
 395    should use gsi_insert_before.  */
 396
 397 void
 398 gsi_insert_before_without_update (gimple_stmt_iterator *i, gimple stmt,
 399                                   enum gsi_iterator_update m)
 400 {
 401   gimple_seq_node n;
 402
 403   n = GGC_NEW (struct gimple_seq_node_d);
 404   n->prev = n->next = NULL;
 405   n->stmt = stmt;
 406   gsi_insert_seq_nodes_before (i, n, n, m);
 407 }
 408
 409 /* Insert statement STMT before the statement pointed-to by iterator I.
 410    Update STMT's basic block and scan it for new operands.  M
 411    specifies how to update iterator I after insertion (see enum
 412    gsi_iterator_update).  */
 413
 414 void
 415 gsi_insert_before (gimple_stmt_iterator *i, gimple stmt,
 416                    enum gsi_iterator_update m)
 417 {
 418   update_modified_stmt (stmt);
 419   gsi_insert_before_without_update (i, stmt, m);
 420 }
 421
 422
 423 /* Insert statement STMT after the statement pointed-to by iterator I.
 424    M specifies how to update iterator I after insertion (see enum
 425    gsi_iterator_update).
 426
 427    This function does not scan for new operands.  It is provided for
 428    the use of the gimplifier, which manipulates statements for which
 429    def/use information has not yet been constructed.  Most callers
 430    should use gsi_insert_after.  */
 431
 432 void
 433 gsi_insert_after_without_update (gimple_stmt_iterator *i, gimple stmt,
 434                                  enum gsi_iterator_update m)
 435 {
 436   gimple_seq_node n;
 437
 438   n = GGC_NEW (struct gimple_seq_node_d);
 439   n->prev = n->next = NULL;
 440   n->stmt = stmt;
 441   gsi_insert_seq_nodes_after (i, n, n, m);
 442 }
 443
 444
 445 /* Insert statement STMT after the statement pointed-to by iterator I.
 446    Update STMT's basic block and scan it for new operands.  M
 447    specifies how to update iterator I after insertion (see enum
 448    gsi_iterator_update).  */
 449
 450 void
 451 gsi_insert_after (gimple_stmt_iterator *i, gimple stmt,
 452                   enum gsi_iterator_update m)
 453 {
 454   update_modified_stmt (stmt);
 455   gsi_insert_after_without_update (i, stmt, m);
 456 }
 457
 458
 459 /* Remove the current stmt from the sequence.  The iterator is updated
 460    to point to the next statement.
 461
 462    REMOVE_PERMANENTLY is true when the statement is going to be removed
 463    from the IL and not reinserted elsewhere.  In that case we remove the
 464    statement pointed to by iterator I from the EH tables, and free its
 465    operand caches.  Otherwise we do not modify this information.  */
 466
 467 void
 468 gsi_remove (gimple_stmt_iterator *i, bool remove_permanently)
 469 {
 470   gimple_seq_node cur, next, prev;
 471   gimple stmt = gsi_stmt (*i);
 472
 473   /* Free all the data flow information for STMT.  */
 474   gimple_set_bb (stmt, NULL);
 475   delink_stmt_imm_use (stmt);
 476   gimple_set_modified (stmt, true);
 477
 478   if (remove_permanently)
 479     {
 480       remove_stmt_from_eh_lp (stmt);
 481       gimple_remove_stmt_histograms (cfun, stmt);
 482     }
 483
 484   /* Update the iterator and re-wire the links in I->SEQ.  */
 485   cur = i->ptr;
 486   next = cur->next;
 487   prev = cur->prev;
 488
 489   if (prev)
 490     prev->next = next;
 491   else
 492     gimple_seq_set_first (i->seq, next);
 493
 494   if (next)
 495     next->prev = prev;
 496   else
 497     gimple_seq_set_last (i->seq, prev);
 498
 499   i->ptr = next;
 500 }
 501
 502
 503 /* Finds iterator for STMT.  */
 504
 505 gimple_stmt_iterator
 506 gsi_for_stmt (gimple stmt)
 507 {
 508   gimple_stmt_iterator i;
 509   basic_block bb = gimple_bb (stmt);
 510
 511   if (gimple_code (stmt) == GIMPLE_PHI)
 512     i = gsi_start_phis (bb);
 513   else
 514     i = gsi_start_bb (bb);
 515
 516   for (; !gsi_end_p (i); gsi_next (&i))
 517     if (gsi_stmt (i) == stmt)
 518       return i;
 519
 520   gcc_unreachable ();
 521 }
 522
 523
 524 /* Move the statement at FROM so it comes right after the statement at TO.  */
 525
 526 void
 527 gsi_move_after (gimple_stmt_iterator *from, gimple_stmt_iterator *to)
 528 {
 529   gimple stmt = gsi_stmt (*from);
 530   gsi_remove (from, false);
 531
 532   /* We must have GSI_NEW_STMT here, as gsi_move_after is sometimes used to
 533      move statements to an empty block.  */
 534   gsi_insert_after (to, stmt, GSI_NEW_STMT);
 535 }
 536
 537
 538 /* Move the statement at FROM so it comes right before the statement
 539    at TO.  */
 540
 541 void
 542 gsi_move_before (gimple_stmt_iterator *from, gimple_stmt_iterator *to)
 543 {
 544   gimple stmt = gsi_stmt (*from);
 545   gsi_remove (from, false);
 546
 547   /* For consistency with gsi_move_after, it might be better to have
 548      GSI_NEW_STMT here; however, that breaks several places that expect
 549      that TO does not change.  */
 550   gsi_insert_before (to, stmt, GSI_SAME_STMT);
 551 }
 552
 553
 554 /* Move the statement at FROM to the end of basic block BB.  */
 555
 556 void
 557 gsi_move_to_bb_end (gimple_stmt_iterator *from, basic_block bb)
 558 {
 559   gimple_stmt_iterator last = gsi_last_bb (bb);
 560 #ifdef ENABLE_CHECKING
 561   gcc_assert (gsi_bb (last) == bb);
 562 #endif
 563
 564   /* Have to check gsi_end_p because it could be an empty block.  */
 565   if (!gsi_end_p (last) && is_ctrl_stmt (gsi_stmt (last)))
 566     gsi_move_before (from, &last);
 567   else
 568     gsi_move_after (from, &last);
 569 }
 570
 571
 572 /* Add STMT to the pending list of edge E.  No actual insertion is
 573    made until a call to gsi_commit_edge_inserts () is made.  */
 574
 575 void
 576 gsi_insert_on_edge (edge e, gimple stmt)
 577 {
 578   gimple_seq_add_stmt (&PENDING_STMT (e), stmt);
 579 }
 580
 581 /* Add the sequence of statements SEQ to the pending list of edge E.
 582    No actual insertion is made until a call to gsi_commit_edge_inserts
 583    is made.  */
 584
 585 void
 586 gsi_insert_seq_on_edge (edge e, gimple_seq seq)
 587 {
 588   gimple_seq_add_seq (&PENDING_STMT (e), seq);
 589 }
 590
 591
 592 /* Insert the statement pointed-to by GSI into edge E.  Every attempt
 593    is made to place the statement in an existing basic block, but
 594    sometimes that isn't possible.  When it isn't possible, the edge is
 595    split and the statement is added to the new block.
 596
 597    In all cases, the returned *GSI points to the correct location.  The
 598    return value is true if insertion should be done after the location,
 599    or false if it should be done before the location.  If a new basic block
 600    has to be created, it is stored in *NEW_BB.  */
 601
 602 static bool
 603 gimple_find_edge_insert_loc (edge e, gimple_stmt_iterator *gsi,
 604                              basic_block *new_bb)
 605 {
 606   basic_block dest, src;
 607   gimple tmp;
 608
 609   dest = e->dest;
 610
 611   /* If the destination has one predecessor which has no PHI nodes,
 612      insert there.  Except for the exit block.
 613
 614      The requirement for no PHI nodes could be relaxed.  Basically we
 615      would have to examine the PHIs to prove that none of them used
 616      the value set by the statement we want to insert on E.  That
 617      hardly seems worth the effort.  */
 618  restart:
 619   if (single_pred_p (dest)
 620       && gimple_seq_empty_p (phi_nodes (dest))
 621       && dest != EXIT_BLOCK_PTR)
 622     {
 623       *gsi = gsi_start_bb (dest);
 624       if (gsi_end_p (*gsi))
 625         return true;
 626
 627       /* Make sure we insert after any leading labels.  */
 628       tmp = gsi_stmt (*gsi);
 629       while (gimple_code (tmp) == GIMPLE_LABEL)
 630         {
 631           gsi_next (gsi);
 632           if (gsi_end_p (*gsi))
 633             break;
 634           tmp = gsi_stmt (*gsi);
 635         }
 636
 637       if (gsi_end_p (*gsi))
 638         {
 639           *gsi = gsi_last_bb (dest);
 640           return true;
 641         }
 642       else
 643         return false;
 644     }
 645
 646   /* If the source has one successor, the edge is not abnormal and
 647      the last statement does not end a basic block, insert there.
 648      Except for the entry block.  */
 649   src = e->src;
 650   if ((e->flags & EDGE_ABNORMAL) == 0
 651       && single_succ_p (src)
 652       && src != ENTRY_BLOCK_PTR)
 653     {
 654       *gsi = gsi_last_bb (src);
 655       if (gsi_end_p (*gsi))
 656         return true;
 657
 658       tmp = gsi_stmt (*gsi);
 659       if (!stmt_ends_bb_p (tmp))
 660         return true;
 661
 662       switch (gimple_code (tmp))
 663         {
 664         case GIMPLE_RETURN:
 665         case GIMPLE_RESX:
 666           return false;
 667         default:
 668           break;
 669         }
 670     }
 671
 672   /* Otherwise, create a new basic block, and split this edge.  */
 673   dest = split_edge (e);
 674   if (new_bb)
 675     *new_bb = dest;
 676   e = single_pred_edge (dest);
 677   goto restart;
 678 }
 679
 680
 681 /* Similar to gsi_insert_on_edge+gsi_commit_edge_inserts.  If a new
 682    block has to be created, it is returned.  */
 683
 684 basic_block
 685 gsi_insert_on_edge_immediate (edge e, gimple stmt)
 686 {
 687   gimple_stmt_iterator gsi;
 688   basic_block new_bb = NULL;
 689
 690   gcc_assert (!PENDING_STMT (e));
 691
 692   if (gimple_find_edge_insert_loc (e, &gsi, &new_bb))
 693     gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
 694   else
 695     gsi_insert_before (&gsi, stmt, GSI_NEW_STMT);
 696
 697   return new_bb;
 698 }
 699
 700 /* Insert STMTS on edge E.  If a new block has to be created, it
 701    is returned.  */
 702
 703 basic_block
 704 gsi_insert_seq_on_edge_immediate (edge e, gimple_seq stmts)
 705 {
 706   gimple_stmt_iterator gsi;
 707   basic_block new_bb = NULL;
 708
 709   gcc_assert (!PENDING_STMT (e));
 710
 711   if (gimple_find_edge_insert_loc (e, &gsi, &new_bb))
 712     gsi_insert_seq_after (&gsi, stmts, GSI_NEW_STMT);
 713   else
 714     gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT);
 715
 716   return new_bb;
 717 }
 718
 719 /* This routine will commit all pending edge insertions, creating any new
 720    basic blocks which are necessary.  */
 721
 722 void
 723 gsi_commit_edge_inserts (void)
 724 {
 725   basic_block bb;
 726   edge e;
 727   edge_iterator ei;
 728
 729   gsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
 730
 731   FOR_EACH_BB (bb)
 732     FOR_EACH_EDGE (e, ei, bb->succs)
 733       gsi_commit_one_edge_insert (e, NULL);
 734 }
 735
 736
 737 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
 738    to this block, otherwise set it to NULL.  */
 739
 740 void
 741 gsi_commit_one_edge_insert (edge e, basic_block *new_bb)
 742 {
 743   if (new_bb)
 744     *new_bb = NULL;
 745
 746   if (PENDING_STMT (e))
 747     {
 748       gimple_stmt_iterator gsi;
 749       gimple_seq seq = PENDING_STMT (e);
 750
 751       PENDING_STMT (e) = NULL;
 752
 753       if (gimple_find_edge_insert_loc (e, &gsi, new_bb))
 754         gsi_insert_seq_after (&gsi, seq, GSI_NEW_STMT);
 755       else
 756         gsi_insert_seq_before (&gsi, seq, GSI_NEW_STMT);
 757     }
 758 }
 759
 760 /* Returns iterator at the start of the list of phi nodes of BB.  */
 761
 762 gimple_stmt_iterator
 763 gsi_start_phis (basic_block bb)
 764 {
 765   return gsi_start (phi_nodes (bb));
 766 }