gcc/tree-optimize.c

   1 /* Top-level control of tree optimizations.
   2    Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    Contributed by Diego Novillo <dnovillo@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "rtl.h"
  28 #include "tm_p.h"
  29 #include "hard-reg-set.h"
  30 #include "basic-block.h"
  31 #include "output.h"
  32 #include "expr.h"
  33 #include "diagnostic.h"
  34 #include "basic-block.h"
  35 #include "flags.h"
  36 #include "tree-flow.h"
  37 #include "tree-dump.h"
  38 #include "timevar.h"
  39 #include "function.h"
  40 #include "langhooks.h"
  41 #include "toplev.h"
  42 #include "flags.h"
  43 #include "cgraph.h"
  44 #include "tree-inline.h"
  45 #include "tree-mudflap.h"
  46 #include "tree-pass.h"
  47 #include "ggc.h"
  48 #include "cgraph.h"
  49 #include "graph.h"
  50 #include "cfgloop.h"
  51
  52
  53 /* Global variables used to communicate with passes.  */
  54 int dump_flags;
  55 bool in_gimple_form;
  56
  57 /* The root of the compilation pass tree, once constructed.  */
  58 static struct tree_opt_pass *all_passes;
  59
  60 /* Pass: dump the gimplified, inlined, functions.  */
  61
  62 static struct tree_opt_pass pass_gimple =
  63 {
  64   "gimple",                             /* name */
  65   NULL,                                 /* gate */
  66   NULL,                                 /* execute */
  67   NULL,                                 /* sub */
  68   NULL,                                 /* next */
  69   0,                                    /* static_pass_number */
  70   0,                                    /* tv_id */
  71   0,                                    /* properties_required */
  72   PROP_gimple_any,                      /* properties_provided */
  73   0,                                    /* properties_destroyed */
  74   0,                                    /* todo_flags_start */
  75   TODO_dump_func,                       /* todo_flags_finish */
  76   0                                     /* letter */
  77 };
  78
  79 /* Gate: execute, or not, all of the non-trivial optimizations.  */
  80
  81 static bool
  82 gate_all_optimizations (void)
  83 {
  84   return (optimize >= 1
  85           /* Don't bother doing anything if the program has errors.  */
  86           && !(errorcount || sorrycount));
  87 }
  88
  89 static struct tree_opt_pass pass_all_optimizations =
  90 {
  91   NULL,                                 /* name */
  92   gate_all_optimizations,               /* gate */
  93   NULL,                                 /* execute */
  94   NULL,                                 /* sub */
  95   NULL,                                 /* next */
  96   0,                                    /* static_pass_number */
  97   0,                                    /* tv_id */
  98   0,                                    /* properties_required */
  99   0,                                    /* properties_provided */
 100   0,                                    /* properties_destroyed */
 101   0,                                    /* todo_flags_start */
 102   0,                                    /* todo_flags_finish */
 103   0                                     /* letter */
 104 };
 105
 106 /* Pass: cleanup the CFG just before expanding trees to RTL.
 107    This is just a round of label cleanups and case node grouping
 108    because after the tree optimizers have run such cleanups may
 109    be necessary.  */
 110
 111 static void
 112 execute_cleanup_cfg_post_optimizing (void)
 113 {
 114   cleanup_tree_cfg ();
 115   cleanup_dead_labels ();
 116   group_case_labels ();
 117 }
 118
 119 static struct tree_opt_pass pass_cleanup_cfg_post_optimizing =
 120 {
 121   "final_cleanup",                      /* name */
 122   NULL,                                 /* gate */
 123   execute_cleanup_cfg_post_optimizing,  /* execute */
 124   NULL,                                 /* sub */
 125   NULL,                                 /* next */
 126   0,                                    /* static_pass_number */
 127   0,                                    /* tv_id */
 128   PROP_cfg,                             /* properties_required */
 129   0,                                    /* properties_provided */
 130   0,                                    /* properties_destroyed */
 131   0,                                    /* todo_flags_start */
 132   TODO_dump_func,                                       /* todo_flags_finish */
 133   0                                     /* letter */
 134 };
 135
 136 /* Pass: do the actions required to finish with tree-ssa optimization
 137    passes.  */
 138
 139 static void
 140 execute_free_datastructures (void)
 141 {
 142   tree *chain;
 143
 144   /* ??? This isn't the right place for this.  Worse, it got computed
 145      more or less at random in various passes.  */
 146   free_dominance_info (CDI_DOMINATORS);
 147
 148   /* Emit gotos for implicit jumps.  */
 149   disband_implicit_edges ();
 150
 151   /* Remove the ssa structures.  Do it here since this includes statement
 152      annotations that need to be intact during disband_implicit_edges.  */
 153   delete_tree_ssa ();
 154
 155   /* Re-chain the statements from the blocks.  */
 156   chain = &DECL_SAVED_TREE (current_function_decl);
 157   *chain = alloc_stmt_list ();
 158
 159   /* And get rid of annotations we no longer need.  */
 160   delete_tree_cfg_annotations ();
 161 }
 162
 163 static struct tree_opt_pass pass_free_datastructures =
 164 {
 165   NULL,                                 /* name */
 166   NULL,                                 /* gate */
 167   execute_free_datastructures,                  /* execute */
 168   NULL,                                 /* sub */
 169   NULL,                                 /* next */
 170   0,                                    /* static_pass_number */
 171   0,                                    /* tv_id */
 172   PROP_cfg,                             /* properties_required */
 173   0,                                    /* properties_provided */
 174   0,                                    /* properties_destroyed */
 175   0,                                    /* todo_flags_start */
 176   0,                                    /* todo_flags_finish */
 177   0                                     /* letter */
 178 };
 179
 180
 181 /* Do the actions required to initialize internal data structures used
 182    in tree-ssa optimization passes.  */
 183
 184 static void
 185 execute_init_datastructures (void)
 186 {
 187   /* Allocate hash tables, arrays and other structures.  */
 188   init_tree_ssa ();
 189 }
 190
 191 static struct tree_opt_pass pass_init_datastructures =
 192 {
 193   NULL,                                 /* name */
 194   NULL,                                 /* gate */
 195   execute_init_datastructures,          /* execute */
 196   NULL,                                 /* sub */
 197   NULL,                                 /* next */
 198   0,                                    /* static_pass_number */
 199   0,                                    /* tv_id */
 200   PROP_cfg,                             /* properties_required */
 201   0,                                    /* properties_provided */
 202   0,                                    /* properties_destroyed */
 203   0,                                    /* todo_flags_start */
 204   0,                                    /* todo_flags_finish */
 205   0                                     /* letter */
 206 };
 207
 208 /* Iterate over the pass tree allocating dump file numbers.  We want
 209    to do this depth first, and independent of whether the pass is
 210    enabled or not.  */
 211
 212 static void
 213 register_one_dump_file (struct tree_opt_pass *pass, int n)
 214 {
 215   char *dot_name, *flag_name, *glob_name;
 216   char num[10];
 217
 218   /* See below in next_pass_1.  */
 219   num[0] = '\0';
 220   if (pass->static_pass_number != -1)
 221     sprintf (num, "%d", ((int) pass->static_pass_number < 0
 222                          ? 1 : pass->static_pass_number));
 223
 224   dot_name = concat (".", pass->name, num, NULL);
 225   if (pass->properties_provided & PROP_trees)
 226     {
 227       flag_name = concat ("tree-", pass->name, num, NULL);
 228       glob_name = concat ("tree-", pass->name, NULL);
 229       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 230                                                 TDF_TREE, n + TDI_tree_all, 0);
 231     }
 232   else
 233     {
 234       flag_name = concat ("rtl-", pass->name, num, NULL);
 235       glob_name = concat ("rtl-", pass->name, NULL);
 236       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 237                                                 TDF_RTL, n, pass->letter);
 238     }
 239 }
 240
 241 static int
 242 register_dump_files (struct tree_opt_pass *pass, int properties)
 243 {
 244   static int n = 0;
 245   do
 246     {
 247       int new_properties;
 248       int pass_number;
 249
 250       pass->properties_required = properties;
 251       new_properties =
 252         (properties | pass->properties_provided) & ~pass->properties_destroyed;
 253
 254       /* Reset the counter when we reach RTL-based passes.  */
 255       if ((pass->properties_provided ^ pass->properties_required) & PROP_rtl)
 256         n = 0;
 257
 258       pass_number = n;
 259       if (pass->name)
 260         n++;
 261
 262       if (pass->sub)
 263         new_properties = register_dump_files (pass->sub, new_properties);
 264
 265       /* If we have a gate, combine the properties that we could have with
 266          and without the pass being examined.  */
 267       if (pass->gate)
 268         properties &= new_properties;
 269       else
 270         properties = new_properties;
 271
 272       pass->properties_provided = properties;
 273       if (pass->name)
 274         register_one_dump_file (pass, pass_number);
 275
 276       pass = pass->next;
 277     }
 278   while (pass);
 279
 280   return properties;
 281 }
 282
 283 /* Add a pass to the pass list. Duplicate the pass if it's already
 284    in the list.  */
 285
 286 static struct tree_opt_pass **
 287 next_pass_1 (struct tree_opt_pass **list, struct tree_opt_pass *pass)
 288 {
 289
 290   /* A nonzero static_pass_number indicates that the
 291      pass is already in the list.  */
 292   if (pass->static_pass_number)
 293     {
 294       struct tree_opt_pass *new;
 295
 296       new = xmalloc (sizeof (*new));
 297       memcpy (new, pass, sizeof (*new));
 298
 299       /* Indicate to register_dump_files that this pass has duplicates,
 300          and so it should rename the dump file.  The first instance will
 301          be -1, and be number of duplicates = -static_pass_number - 1.
 302          Subsequent instances will be > 0 and just the duplicate number.  */
 303       if (pass->name)
 304         {
 305           pass->static_pass_number -= 1;
 306           new->static_pass_number = -pass->static_pass_number;
 307         }
 308
 309       *list = new;
 310     }
 311   else
 312     {
 313       pass->static_pass_number = -1;
 314       *list = pass;
 315     }
 316
 317   return &(*list)->next;
 318
 319 }
 320
 321 /* Construct the pass tree.  */
 322
 323 void
 324 init_tree_optimization_passes (void)
 325 {
 326   struct tree_opt_pass **p;
 327
 328 #define NEXT_PASS(PASS)  (p = next_pass_1 (p, &PASS))
 329
 330   p = &all_passes;
 331   NEXT_PASS (pass_gimple);
 332   NEXT_PASS (pass_remove_useless_stmts);
 333   NEXT_PASS (pass_mudflap_1);
 334   NEXT_PASS (pass_lower_cf);
 335   NEXT_PASS (pass_lower_eh);
 336   NEXT_PASS (pass_build_cfg);
 337   NEXT_PASS (pass_pre_expand);
 338   NEXT_PASS (pass_tree_profile);
 339   NEXT_PASS (pass_init_datastructures);
 340   NEXT_PASS (pass_all_optimizations);
 341   NEXT_PASS (pass_warn_function_return);
 342   NEXT_PASS (pass_mudflap_2);
 343   NEXT_PASS (pass_free_datastructures);
 344   NEXT_PASS (pass_expand);
 345   NEXT_PASS (pass_rest_of_compilation);
 346   *p = NULL;
 347
 348   p = &pass_all_optimizations.sub;
 349   NEXT_PASS (pass_referenced_vars);
 350   NEXT_PASS (pass_create_structure_vars);
 351   NEXT_PASS (pass_build_ssa);
 352   NEXT_PASS (pass_may_alias);
 353   NEXT_PASS (pass_rename_ssa_copies);
 354   NEXT_PASS (pass_early_warn_uninitialized);
 355   NEXT_PASS (pass_dce);
 356   NEXT_PASS (pass_dominator);
 357   NEXT_PASS (pass_copy_prop);
 358   NEXT_PASS (pass_dce);
 359   NEXT_PASS (pass_forwprop);
 360   NEXT_PASS (pass_vrp);
 361   NEXT_PASS (pass_merge_phi);
 362   NEXT_PASS (pass_phiopt);
 363   NEXT_PASS (pass_may_alias);
 364   NEXT_PASS (pass_tail_recursion);
 365   NEXT_PASS (pass_ch);
 366   NEXT_PASS (pass_profile);
 367   NEXT_PASS (pass_stdarg);
 368   NEXT_PASS (pass_sra);
 369   /* FIXME: SRA may generate arbitrary gimple code, exposing new
 370      aliased and call-clobbered variables.  As mentioned below,
 371      pass_may_alias should be a TODO item.  */
 372   NEXT_PASS (pass_may_alias);
 373   NEXT_PASS (pass_rename_ssa_copies);
 374   NEXT_PASS (pass_dominator);
 375   NEXT_PASS (pass_copy_prop);
 376   NEXT_PASS (pass_dce);
 377   NEXT_PASS (pass_dse);
 378   NEXT_PASS (pass_may_alias);
 379   NEXT_PASS (pass_forwprop);
 380   NEXT_PASS (pass_phiopt);
 381   NEXT_PASS (pass_store_ccp);
 382   NEXT_PASS (pass_store_copy_prop);
 383   NEXT_PASS (pass_fold_builtins);
 384   /* FIXME: May alias should a TODO but for 4.0.0,
 385      we add may_alias right after fold builtins
 386      which can create arbitrary GIMPLE.  */
 387   NEXT_PASS (pass_may_alias);
 388   NEXT_PASS (pass_split_crit_edges);
 389   NEXT_PASS (pass_pre);
 390   NEXT_PASS (pass_sink_code);
 391   NEXT_PASS (pass_loop);
 392   NEXT_PASS (pass_dominator);
 393   NEXT_PASS (pass_copy_prop);
 394   /* FIXME: If DCE is not run before checking for uninitialized uses,
 395      we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
 396      However, this also causes us to misdiagnose cases that should be
 397      real warnings (e.g., testsuite/gcc.dg/pr18501.c).
 398
 399      To fix the false positives in uninit-5.c, we would have to
 400      account for the predicates protecting the set and the use of each
 401      variable.  Using a representation like Gated Single Assignment
 402      may help.  */
 403   NEXT_PASS (pass_late_warn_uninitialized);
 404   NEXT_PASS (pass_cd_dce);
 405   NEXT_PASS (pass_dse);
 406   NEXT_PASS (pass_forwprop);
 407   NEXT_PASS (pass_phiopt);
 408   NEXT_PASS (pass_tail_calls);
 409   NEXT_PASS (pass_rename_ssa_copies);
 410   NEXT_PASS (pass_uncprop);
 411   NEXT_PASS (pass_del_ssa);
 412   NEXT_PASS (pass_nrv);
 413   NEXT_PASS (pass_remove_useless_vars);
 414   NEXT_PASS (pass_mark_used_blocks);
 415   NEXT_PASS (pass_cleanup_cfg_post_optimizing);
 416   *p = NULL;
 417
 418   p = &pass_loop.sub;
 419   NEXT_PASS (pass_loop_init);
 420   NEXT_PASS (pass_copy_prop);
 421   NEXT_PASS (pass_lim);
 422   NEXT_PASS (pass_unswitch);
 423   NEXT_PASS (pass_record_bounds);
 424   NEXT_PASS (pass_linear_transform);
 425   NEXT_PASS (pass_iv_canon);
 426   NEXT_PASS (pass_if_conversion);
 427   NEXT_PASS (pass_vectorize);
 428   NEXT_PASS (pass_complete_unroll);
 429   NEXT_PASS (pass_iv_optimize);
 430   NEXT_PASS (pass_loop_done);
 431   *p = NULL;
 432
 433 #undef NEXT_PASS
 434
 435   /* Register the passes with the tree dump code.  */
 436   register_dump_files (all_passes, 0);
 437 }
 438
 439 static void execute_pass_list (struct tree_opt_pass *);
 440
 441 static unsigned int last_verified;
 442
 443 static void
 444 execute_todo (struct tree_opt_pass *pass, unsigned int flags, bool use_required)
 445 {
 446   int properties
 447     = use_required ? pass->properties_required : pass->properties_provided;
 448
 449 #if defined ENABLE_CHECKING
 450   if (need_ssa_update_p ())
 451     gcc_assert (flags & TODO_update_ssa_any);
 452 #endif
 453
 454   if (flags & TODO_update_ssa_any)
 455     {
 456       unsigned update_flags = flags & TODO_update_ssa_any;
 457       update_ssa (update_flags);
 458     }
 459
 460   if (flags & TODO_cleanup_cfg)
 461     {
 462       if (current_loops)
 463         cleanup_tree_cfg_loop ();
 464       else
 465         cleanup_tree_cfg ();
 466     }
 467
 468   if ((flags & TODO_dump_func) && dump_file)
 469     {
 470       if (properties & PROP_trees)
 471         dump_function_to_file (current_function_decl,
 472                                dump_file, dump_flags);
 473       else if (properties & PROP_cfg)
 474         print_rtl_with_bb (dump_file, get_insns ());
 475       else
 476         print_rtl (dump_file, get_insns ());
 477
 478       /* Flush the file.  If verification fails, we won't be able to
 479          close the file before aborting.  */
 480       fflush (dump_file);
 481     }
 482
 483   if (flags & TODO_ggc_collect)
 484     {
 485       ggc_collect ();
 486     }
 487
 488 #if defined ENABLE_CHECKING
 489   if ((pass->properties_required & PROP_ssa)
 490       && !(pass->properties_destroyed & PROP_ssa))
 491     verify_ssa (true);
 492   if (flags & TODO_verify_flow)
 493     verify_flow_info ();
 494   if (flags & TODO_verify_stmts)
 495     verify_stmts ();
 496   if (flags & TODO_verify_loops)
 497     verify_loop_closed_ssa ();
 498 #endif
 499 }
 500
 501 static bool
 502 execute_one_pass (struct tree_opt_pass *pass)
 503 {
 504   unsigned int todo;
 505
 506   /* See if we're supposed to run this pass.  */
 507   if (pass->gate && !pass->gate ())
 508     return false;
 509
 510   /* Note that the folders should only create gimple expressions.
 511      This is a hack until the new folder is ready.  */
 512   in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
 513
 514   /* Run pre-pass verification.  */
 515   todo = pass->todo_flags_start & ~last_verified;
 516   if (todo)
 517     execute_todo (pass, todo, true);
 518
 519   /* If a dump file name is present, open it if enabled.  */
 520   if (pass->static_pass_number != -1)
 521     {
 522       bool initializing_dump = !dump_initialized_p (pass->static_pass_number);
 523       dump_file_name = get_dump_file_name (pass->static_pass_number);
 524       dump_file = dump_begin (pass->static_pass_number, &dump_flags);
 525       if (dump_file)
 526         {
 527           const char *dname, *aname;
 528           dname = lang_hooks.decl_printable_name (current_function_decl, 2);
 529           aname = (IDENTIFIER_POINTER
 530                    (DECL_ASSEMBLER_NAME (current_function_decl)));
 531           fprintf (dump_file, "\n;; Function %s (%s)%s\n\n", dname, aname,
 532              cfun->function_frequency == FUNCTION_FREQUENCY_HOT
 533              ? " (hot)"
 534              : cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
 535              ? " (unlikely executed)"
 536              : "");
 537         }
 538
 539       if (initializing_dump
 540           && graph_dump_format != no_graph
 541           && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 542               == (PROP_cfg | PROP_rtl))
 543         clean_graph_dump_file (dump_file_name);
 544     }
 545
 546   /* If a timevar is present, start it.  */
 547   if (pass->tv_id)
 548     timevar_push (pass->tv_id);
 549
 550   /* Do it!  */
 551   if (pass->execute)
 552     pass->execute ();
 553
 554   /* Stop timevar.  */
 555   if (pass->tv_id)
 556     timevar_pop (pass->tv_id);
 557
 558   if (dump_file
 559       && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 560           == (PROP_cfg | PROP_rtl))
 561     print_rtl_with_bb (dump_file, get_insns ());
 562
 563   /* Run post-pass cleanup and verification.  */
 564   todo = pass->todo_flags_finish;
 565   last_verified = todo & TODO_verify_all;
 566   if (todo)
 567     execute_todo (pass, todo, false);
 568
 569   /* Flush and close dump file.  */
 570   if (dump_file_name)
 571     {
 572       free ((char *) dump_file_name);
 573       dump_file_name = NULL;
 574     }
 575   if (dump_file)
 576     {
 577       dump_end (pass->static_pass_number, dump_file);
 578       dump_file = NULL;
 579     }
 580
 581   return true;
 582 }
 583
 584 static void
 585 execute_pass_list (struct tree_opt_pass *pass)
 586 {
 587   do
 588     {
 589       if (execute_one_pass (pass) && pass->sub)
 590         execute_pass_list (pass->sub);
 591       pass = pass->next;
 592     }
 593   while (pass);
 594 }
 595 \f
 596
 597 /* Update recursively all inlined_to pointers of functions
 598    inlined into NODE to INLINED_TO.  */
 599 static void
 600 update_inlined_to_pointers (struct cgraph_node *node,
 601                             struct cgraph_node *inlined_to)
 602 {
 603   struct cgraph_edge *e;
 604   for (e = node->callees; e; e = e->next_callee)
 605     {
 606       if (e->callee->global.inlined_to)
 607         {
 608           e->callee->global.inlined_to = inlined_to;
 609           update_inlined_to_pointers (e->callee, inlined_to);
 610         }
 611     }
 612 }
 613
 614 \f
 615 /* For functions-as-trees languages, this performs all optimization and
 616    compilation for FNDECL.  */
 617
 618 void
 619 tree_rest_of_compilation (tree fndecl)
 620 {
 621   location_t saved_loc;
 622   struct cgraph_node *saved_node = NULL, *node;
 623
 624   timevar_push (TV_EXPAND);
 625
 626   gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);
 627
 628   /* Initialize the RTL code for the function.  */
 629   current_function_decl = fndecl;
 630   saved_loc = input_location;
 631   input_location = DECL_SOURCE_LOCATION (fndecl);
 632   init_function_start (fndecl);
 633
 634   /* Even though we're inside a function body, we still don't want to
 635      call expand_expr to calculate the size of a variable-sized array.
 636      We haven't necessarily assigned RTL to all variables yet, so it's
 637      not safe to try to expand expressions involving them.  */
 638   cfun->x_dont_save_pending_sizes_p = 1;
 639
 640   node = cgraph_node (fndecl);
 641
 642   /* We might need the body of this function so that we can expand
 643      it inline somewhere else.  This means not lowering some constructs
 644      such as exception handling.  */
 645   if (cgraph_preserve_function_body_p (fndecl))
 646     {
 647       if (!flag_unit_at_a_time)
 648         {
 649           struct cgraph_edge *e;
 650
 651           saved_node = cgraph_clone_node (node);
 652           for (e = saved_node->callees; e; e = e->next_callee)
 653             if (!e->inline_failed)
 654               cgraph_clone_inlined_nodes (e, true);
 655         }
 656       cfun->saved_static_chain_decl = cfun->static_chain_decl;
 657       cfun->saved_tree = save_body (fndecl, &cfun->saved_args,
 658                                     &cfun->saved_static_chain_decl);
 659     }
 660
 661   if (flag_inline_trees)
 662     {
 663       struct cgraph_edge *e;
 664       for (e = node->callees; e; e = e->next_callee)
 665         if (!e->inline_failed || warn_inline)
 666           break;
 667       if (e)
 668         {
 669           timevar_push (TV_INTEGRATION);
 670           optimize_inline_calls (fndecl);
 671           timevar_pop (TV_INTEGRATION);
 672         }
 673     }
 674   /* We are not going to maintain the cgraph edges up to date.
 675      Kill it so it won't confuse us.  */
 676   while (node->callees)
 677     {
 678       /* In non-unit-at-a-time we must mark all referenced functions as needed.
 679          */
 680       if (node->callees->callee->analyzed && !flag_unit_at_a_time)
 681         cgraph_mark_needed_node (node->callees->callee);
 682       cgraph_remove_edge (node->callees);
 683     }
 684
 685   /* We are not going to maintain the cgraph edges up to date.
 686      Kill it so it won't confuse us.  */
 687   cgraph_node_remove_callees (node);
 688
 689
 690   /* Initialize the default bitmap obstack.  */
 691   bitmap_obstack_initialize (NULL);
 692   bitmap_obstack_initialize (&reg_obstack); /* FIXME, only at RTL generation*/
 693
 694   /* Perform all tree transforms and optimizations.  */
 695   execute_pass_list (all_passes);
 696
 697   bitmap_obstack_release (&reg_obstack);
 698
 699   /* Release the default bitmap obstack.  */
 700   bitmap_obstack_release (NULL);
 701
 702   /* Restore original body if still needed.  */
 703   if (cfun->saved_tree)
 704     {
 705       DECL_SAVED_TREE (fndecl) = cfun->saved_tree;
 706       DECL_ARGUMENTS (fndecl) = cfun->saved_args;
 707       cfun->static_chain_decl = cfun->saved_static_chain_decl;
 708
 709       /* When not in unit-at-a-time mode, we must preserve out of line copy
 710          representing node before inlining.  Restore original outgoing edges
 711          using clone we created earlier.  */
 712       if (!flag_unit_at_a_time)
 713         {
 714           struct cgraph_edge *e;
 715
 716           cgraph_node_remove_callees (node);
 717           node->callees = saved_node->callees;
 718           saved_node->callees = NULL;
 719           update_inlined_to_pointers (node, node);
 720           for (e = node->callees; e; e = e->next_callee)
 721             e->caller = node;
 722           cgraph_remove_node (saved_node);
 723         }
 724     }
 725   else
 726     DECL_SAVED_TREE (fndecl) = NULL;
 727   cfun = 0;
 728
 729   /* If requested, warn about function definitions where the function will
 730      return a value (usually of some struct or union type) which itself will
 731      take up a lot of stack space.  */
 732   if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
 733     {
 734       tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
 735
 736       if (ret_type && TYPE_SIZE_UNIT (ret_type)
 737           && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
 738           && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
 739                                    larger_than_size))
 740         {
 741           unsigned int size_as_int
 742             = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
 743
 744           if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
 745             warning ("%Jsize of return value of %qD is %u bytes",
 746                      fndecl, fndecl, size_as_int);
 747           else
 748             warning ("%Jsize of return value of %qD is larger than %wd bytes",
 749                      fndecl, fndecl, larger_than_size);
 750         }
 751     }
 752
 753   if (!flag_inline_trees)
 754     {
 755       DECL_SAVED_TREE (fndecl) = NULL;
 756       if (DECL_STRUCT_FUNCTION (fndecl) == 0
 757           && !cgraph_node (fndecl)->origin)
 758         {
 759           /* Stop pointing to the local nodes about to be freed.
 760              But DECL_INITIAL must remain nonzero so we know this
 761              was an actual function definition.
 762              For a nested function, this is done in c_pop_function_context.
 763              If rest_of_compilation set this to 0, leave it 0.  */
 764           if (DECL_INITIAL (fndecl) != 0)
 765             DECL_INITIAL (fndecl) = error_mark_node;
 766         }
 767     }
 768
 769   input_location = saved_loc;
 770
 771   ggc_collect ();
 772   timevar_pop (TV_EXPAND);
 773 }