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, *all_ipa_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, bool ipa, 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 (ipa)
 226     {
 227       flag_name = concat ("ipa-", pass->name, num, NULL);
 228       glob_name = concat ("ipa-", pass->name, NULL);
 229       /* First IPA dump is cgraph that is dumped via separate channels.  */
 230       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 231                                                 TDF_IPA, n + 1, 0);
 232     }
 233   else if (pass->properties_provided & PROP_trees)
 234     {
 235       flag_name = concat ("tree-", pass->name, num, NULL);
 236       glob_name = concat ("tree-", pass->name, NULL);
 237       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 238                                                 TDF_TREE, n + TDI_tree_all, 0);
 239     }
 240   else
 241     {
 242       flag_name = concat ("rtl-", pass->name, num, NULL);
 243       glob_name = concat ("rtl-", pass->name, NULL);
 244       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 245                                                 TDF_RTL, n, pass->letter);
 246     }
 247 }
 248
 249 static int
 250 register_dump_files (struct tree_opt_pass *pass, bool ipa, int properties)
 251 {
 252   static int n = 0;
 253   do
 254     {
 255       int new_properties;
 256       int pass_number;
 257
 258       pass->properties_required = properties;
 259       new_properties =
 260         (properties | pass->properties_provided) & ~pass->properties_destroyed;
 261
 262       /* Reset the counter when we reach RTL-based passes.  */
 263       if ((pass->properties_provided ^ pass->properties_required) & PROP_rtl)
 264         n = 0;
 265
 266       pass_number = n;
 267       if (pass->name)
 268         n++;
 269
 270       if (pass->sub)
 271         new_properties = register_dump_files (pass->sub, ipa, new_properties);
 272
 273       /* If we have a gate, combine the properties that we could have with
 274          and without the pass being examined.  */
 275       if (pass->gate)
 276         properties &= new_properties;
 277       else
 278         properties = new_properties;
 279
 280       pass->properties_provided = properties;
 281       if (pass->name)
 282         register_one_dump_file (pass, ipa, pass_number);
 283
 284       pass = pass->next;
 285     }
 286   while (pass);
 287
 288   return properties;
 289 }
 290
 291 /* Add a pass to the pass list. Duplicate the pass if it's already
 292    in the list.  */
 293
 294 static struct tree_opt_pass **
 295 next_pass_1 (struct tree_opt_pass **list, struct tree_opt_pass *pass)
 296 {
 297
 298   /* A nonzero static_pass_number indicates that the
 299      pass is already in the list.  */
 300   if (pass->static_pass_number)
 301     {
 302       struct tree_opt_pass *new;
 303
 304       new = xmalloc (sizeof (*new));
 305       memcpy (new, pass, sizeof (*new));
 306
 307       /* Indicate to register_dump_files that this pass has duplicates,
 308          and so it should rename the dump file.  The first instance will
 309          be -1, and be number of duplicates = -static_pass_number - 1.
 310          Subsequent instances will be > 0 and just the duplicate number.  */
 311       if (pass->name)
 312         {
 313           pass->static_pass_number -= 1;
 314           new->static_pass_number = -pass->static_pass_number;
 315         }
 316
 317       *list = new;
 318     }
 319   else
 320     {
 321       pass->static_pass_number = -1;
 322       *list = pass;
 323     }
 324
 325   return &(*list)->next;
 326
 327 }
 328
 329 /* Construct the pass tree.  */
 330
 331 void
 332 init_tree_optimization_passes (void)
 333 {
 334   struct tree_opt_pass **p;
 335
 336 #define NEXT_PASS(PASS)  (p = next_pass_1 (p, &PASS))
 337   /* Intraprocedural optimization passes.  */
 338   p = &all_ipa_passes;
 339   NEXT_PASS (pass_ipa_inline);
 340   *p = NULL;
 341
 342   p = &all_passes;
 343   NEXT_PASS (pass_gimple);
 344   NEXT_PASS (pass_remove_useless_stmts);
 345   NEXT_PASS (pass_mudflap_1);
 346   NEXT_PASS (pass_lower_cf);
 347   NEXT_PASS (pass_lower_eh);
 348   NEXT_PASS (pass_build_cfg);
 349   NEXT_PASS (pass_pre_expand);
 350   NEXT_PASS (pass_tree_profile);
 351   NEXT_PASS (pass_init_datastructures);
 352   NEXT_PASS (pass_all_optimizations);
 353   NEXT_PASS (pass_warn_function_return);
 354   NEXT_PASS (pass_mudflap_2);
 355   NEXT_PASS (pass_free_datastructures);
 356   NEXT_PASS (pass_expand);
 357   NEXT_PASS (pass_rest_of_compilation);
 358   *p = NULL;
 359
 360   p = &pass_all_optimizations.sub;
 361   NEXT_PASS (pass_referenced_vars);
 362   NEXT_PASS (pass_create_structure_vars);
 363   NEXT_PASS (pass_build_ssa);
 364   NEXT_PASS (pass_may_alias);
 365   NEXT_PASS (pass_rename_ssa_copies);
 366   NEXT_PASS (pass_early_warn_uninitialized);
 367   NEXT_PASS (pass_dce);
 368   NEXT_PASS (pass_dominator);
 369   NEXT_PASS (pass_copy_prop);
 370   NEXT_PASS (pass_dce);
 371   NEXT_PASS (pass_forwprop);
 372   NEXT_PASS (pass_vrp);
 373   NEXT_PASS (pass_merge_phi);
 374   NEXT_PASS (pass_phiopt);
 375   NEXT_PASS (pass_may_alias);
 376   NEXT_PASS (pass_tail_recursion);
 377   NEXT_PASS (pass_ch);
 378   NEXT_PASS (pass_profile);
 379   NEXT_PASS (pass_stdarg);
 380   NEXT_PASS (pass_sra);
 381   /* FIXME: SRA may generate arbitrary gimple code, exposing new
 382      aliased and call-clobbered variables.  As mentioned below,
 383      pass_may_alias should be a TODO item.  */
 384   NEXT_PASS (pass_may_alias);
 385   NEXT_PASS (pass_rename_ssa_copies);
 386   NEXT_PASS (pass_dominator);
 387   NEXT_PASS (pass_copy_prop);
 388   NEXT_PASS (pass_dce);
 389   NEXT_PASS (pass_dse);
 390   NEXT_PASS (pass_may_alias);
 391   NEXT_PASS (pass_forwprop);
 392   NEXT_PASS (pass_phiopt);
 393   NEXT_PASS (pass_store_ccp);
 394   NEXT_PASS (pass_store_copy_prop);
 395   NEXT_PASS (pass_fold_builtins);
 396   /* FIXME: May alias should a TODO but for 4.0.0,
 397      we add may_alias right after fold builtins
 398      which can create arbitrary GIMPLE.  */
 399   NEXT_PASS (pass_may_alias);
 400   NEXT_PASS (pass_split_crit_edges);
 401   NEXT_PASS (pass_pre);
 402   NEXT_PASS (pass_sink_code);
 403   NEXT_PASS (pass_loop);
 404   NEXT_PASS (pass_dominator);
 405   NEXT_PASS (pass_copy_prop);
 406   /* FIXME: If DCE is not run before checking for uninitialized uses,
 407      we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
 408      However, this also causes us to misdiagnose cases that should be
 409      real warnings (e.g., testsuite/gcc.dg/pr18501.c).
 410
 411      To fix the false positives in uninit-5.c, we would have to
 412      account for the predicates protecting the set and the use of each
 413      variable.  Using a representation like Gated Single Assignment
 414      may help.  */
 415   NEXT_PASS (pass_late_warn_uninitialized);
 416   NEXT_PASS (pass_cd_dce);
 417   NEXT_PASS (pass_dse);
 418   NEXT_PASS (pass_forwprop);
 419   NEXT_PASS (pass_phiopt);
 420   NEXT_PASS (pass_tail_calls);
 421   NEXT_PASS (pass_rename_ssa_copies);
 422   NEXT_PASS (pass_uncprop);
 423   NEXT_PASS (pass_del_ssa);
 424   NEXT_PASS (pass_nrv);
 425   NEXT_PASS (pass_remove_useless_vars);
 426   NEXT_PASS (pass_mark_used_blocks);
 427   NEXT_PASS (pass_cleanup_cfg_post_optimizing);
 428   *p = NULL;
 429
 430   p = &pass_loop.sub;
 431   NEXT_PASS (pass_loop_init);
 432   NEXT_PASS (pass_copy_prop);
 433   NEXT_PASS (pass_lim);
 434   NEXT_PASS (pass_unswitch);
 435   NEXT_PASS (pass_record_bounds);
 436   NEXT_PASS (pass_linear_transform);
 437   NEXT_PASS (pass_iv_canon);
 438   NEXT_PASS (pass_if_conversion);
 439   NEXT_PASS (pass_vectorize);
 440   NEXT_PASS (pass_lower_vector_ssa);
 441   NEXT_PASS (pass_complete_unroll);
 442   NEXT_PASS (pass_iv_optimize);
 443   NEXT_PASS (pass_loop_done);
 444   *p = NULL;
 445
 446 #undef NEXT_PASS
 447
 448   register_dump_files (all_passes, false, PROP_gimple_any
 449                                           | PROP_gimple_lcf
 450                                           | PROP_gimple_leh
 451                                           | PROP_cfg);
 452   register_dump_files (all_ipa_passes, true, PROP_gimple_any
 453                                              | PROP_gimple_lcf
 454                                              | PROP_gimple_leh
 455                                              | PROP_cfg);
 456 }
 457
 458 static unsigned int last_verified;
 459
 460 static void
 461 execute_todo (struct tree_opt_pass *pass, unsigned int flags, bool use_required)
 462 {
 463   int properties
 464     = use_required ? pass->properties_required : pass->properties_provided;
 465
 466 #if defined ENABLE_CHECKING
 467   if (need_ssa_update_p ())
 468     gcc_assert (flags & TODO_update_ssa_any);
 469 #endif
 470
 471   if (flags & TODO_update_ssa_any)
 472     {
 473       unsigned update_flags = flags & TODO_update_ssa_any;
 474       update_ssa (update_flags);
 475     }
 476
 477   if (flags & TODO_cleanup_cfg)
 478     {
 479       if (current_loops)
 480         cleanup_tree_cfg_loop ();
 481       else
 482         cleanup_tree_cfg ();
 483     }
 484
 485   if ((flags & TODO_dump_func)
 486       && dump_file && current_function_decl)
 487     {
 488       if (properties & PROP_trees)
 489         dump_function_to_file (current_function_decl,
 490                                dump_file, dump_flags);
 491       else if (properties & PROP_cfg)
 492         print_rtl_with_bb (dump_file, get_insns ());
 493       else
 494         print_rtl (dump_file, get_insns ());
 495
 496       /* Flush the file.  If verification fails, we won't be able to
 497          close the file before dieing.  */
 498       fflush (dump_file);
 499     }
 500   if ((flags & TODO_dump_cgraph)
 501       && dump_file && !current_function_decl)
 502     {
 503       dump_cgraph (dump_file);
 504       /* Flush the file.  If verification fails, we won't be able to
 505          close the file before aborting.  */
 506       fflush (dump_file);
 507     }
 508
 509   if (flags & TODO_ggc_collect)
 510     {
 511       ggc_collect ();
 512     }
 513
 514 #if defined ENABLE_CHECKING
 515   if ((pass->properties_required & PROP_ssa)
 516       && !(pass->properties_destroyed & PROP_ssa))
 517     verify_ssa (true);
 518   if (flags & TODO_verify_flow)
 519     verify_flow_info ();
 520   if (flags & TODO_verify_stmts)
 521     verify_stmts ();
 522   if (flags & TODO_verify_loops)
 523     verify_loop_closed_ssa ();
 524 #endif
 525 }
 526
 527 static bool
 528 execute_one_pass (struct tree_opt_pass *pass)
 529 {
 530   unsigned int todo;
 531
 532   /* See if we're supposed to run this pass.  */
 533   if (pass->gate && !pass->gate ())
 534     return false;
 535
 536   /* Note that the folders should only create gimple expressions.
 537      This is a hack until the new folder is ready.  */
 538   in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
 539
 540   /* Run pre-pass verification.  */
 541   todo = pass->todo_flags_start & ~last_verified;
 542   if (todo)
 543     execute_todo (pass, todo, true);
 544
 545   /* If a dump file name is present, open it if enabled.  */
 546   if (pass->static_pass_number != -1)
 547     {
 548       bool initializing_dump = !dump_initialized_p (pass->static_pass_number);
 549       dump_file_name = get_dump_file_name (pass->static_pass_number);
 550       dump_file = dump_begin (pass->static_pass_number, &dump_flags);
 551       if (dump_file && current_function_decl)
 552         {
 553           const char *dname, *aname;
 554           dname = lang_hooks.decl_printable_name (current_function_decl, 2);
 555           aname = (IDENTIFIER_POINTER
 556                    (DECL_ASSEMBLER_NAME (current_function_decl)));
 557           fprintf (dump_file, "\n;; Function %s (%s)%s\n\n", dname, aname,
 558              cfun->function_frequency == FUNCTION_FREQUENCY_HOT
 559              ? " (hot)"
 560              : cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
 561              ? " (unlikely executed)"
 562              : "");
 563         }
 564
 565       if (initializing_dump
 566           && graph_dump_format != no_graph
 567           && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 568               == (PROP_cfg | PROP_rtl))
 569         clean_graph_dump_file (dump_file_name);
 570     }
 571
 572   /* If a timevar is present, start it.  */
 573   if (pass->tv_id)
 574     timevar_push (pass->tv_id);
 575
 576   /* Do it!  */
 577   if (pass->execute)
 578     pass->execute ();
 579
 580   /* Stop timevar.  */
 581   if (pass->tv_id)
 582     timevar_pop (pass->tv_id);
 583
 584   if (dump_file
 585       && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 586           == (PROP_cfg | PROP_rtl))
 587     print_rtl_with_bb (dump_file, get_insns ());
 588
 589   /* Run post-pass cleanup and verification.  */
 590   todo = pass->todo_flags_finish;
 591   last_verified = todo & TODO_verify_all;
 592   if (todo)
 593     execute_todo (pass, todo, false);
 594
 595   /* Flush and close dump file.  */
 596   if (dump_file_name)
 597     {
 598       free ((char *) dump_file_name);
 599       dump_file_name = NULL;
 600     }
 601   if (dump_file)
 602     {
 603       dump_end (pass->static_pass_number, dump_file);
 604       dump_file = NULL;
 605     }
 606
 607   return true;
 608 }
 609
 610 static void
 611 execute_pass_list (struct tree_opt_pass *pass)
 612 {
 613   do
 614     {
 615       if (execute_one_pass (pass) && pass->sub)
 616         execute_pass_list (pass->sub);
 617       pass = pass->next;
 618     }
 619   while (pass);
 620 }
 621
 622 /* Execute all IPA passes.  */
 623 void
 624 ipa_passes (void)
 625 {
 626    execute_pass_list (all_ipa_passes);
 627 }
 628 \f
 629
 630 /* Update recursively all inlined_to pointers of functions
 631    inlined into NODE to INLINED_TO.  */
 632 static void
 633 update_inlined_to_pointers (struct cgraph_node *node,
 634                             struct cgraph_node *inlined_to)
 635 {
 636   struct cgraph_edge *e;
 637   for (e = node->callees; e; e = e->next_callee)
 638     {
 639       if (e->callee->global.inlined_to)
 640         {
 641           e->callee->global.inlined_to = inlined_to;
 642           update_inlined_to_pointers (e->callee, inlined_to);
 643         }
 644     }
 645 }
 646
 647 \f
 648 /* For functions-as-trees languages, this performs all optimization and
 649    compilation for FNDECL.  */
 650
 651 void
 652 tree_rest_of_compilation (tree fndecl)
 653 {
 654   location_t saved_loc;
 655   struct cgraph_node *saved_node = NULL, *node;
 656
 657   timevar_push (TV_EXPAND);
 658
 659   gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);
 660
 661   /* Initialize the RTL code for the function.  */
 662   current_function_decl = fndecl;
 663   saved_loc = input_location;
 664   input_location = DECL_SOURCE_LOCATION (fndecl);
 665   init_function_start (fndecl);
 666
 667   /* Even though we're inside a function body, we still don't want to
 668      call expand_expr to calculate the size of a variable-sized array.
 669      We haven't necessarily assigned RTL to all variables yet, so it's
 670      not safe to try to expand expressions involving them.  */
 671   cfun->x_dont_save_pending_sizes_p = 1;
 672
 673   node = cgraph_node (fndecl);
 674
 675   /* We might need the body of this function so that we can expand
 676      it inline somewhere else.  This means not lowering some constructs
 677      such as exception handling.  */
 678   if (cgraph_preserve_function_body_p (fndecl))
 679     {
 680       if (!flag_unit_at_a_time)
 681         {
 682           struct cgraph_edge *e;
 683
 684           saved_node = cgraph_clone_node (node);
 685           for (e = saved_node->callees; e; e = e->next_callee)
 686             if (!e->inline_failed)
 687               cgraph_clone_inlined_nodes (e, true);
 688         }
 689       cfun->saved_static_chain_decl = cfun->static_chain_decl;
 690       cfun->saved_tree = save_body (fndecl, &cfun->saved_args,
 691                                     &cfun->saved_static_chain_decl);
 692     }
 693
 694   if (flag_inline_trees)
 695     {
 696       struct cgraph_edge *e;
 697       for (e = node->callees; e; e = e->next_callee)
 698         if (!e->inline_failed || warn_inline)
 699           break;
 700       if (e)
 701         {
 702           timevar_push (TV_INTEGRATION);
 703           optimize_inline_calls (fndecl);
 704           timevar_pop (TV_INTEGRATION);
 705         }
 706     }
 707   /* We are not going to maintain the cgraph edges up to date.
 708      Kill it so it won't confuse us.  */
 709   while (node->callees)
 710     {
 711       /* In non-unit-at-a-time we must mark all referenced functions as needed.
 712          */
 713       if (node->callees->callee->analyzed && !flag_unit_at_a_time)
 714         cgraph_mark_needed_node (node->callees->callee);
 715       cgraph_remove_edge (node->callees);
 716     }
 717
 718   /* We are not going to maintain the cgraph edges up to date.
 719      Kill it so it won't confuse us.  */
 720   cgraph_node_remove_callees (node);
 721
 722
 723   /* Initialize the default bitmap obstack.  */
 724   bitmap_obstack_initialize (NULL);
 725   bitmap_obstack_initialize (&reg_obstack); /* FIXME, only at RTL generation*/
 726
 727   /* Perform all tree transforms and optimizations.  */
 728   execute_pass_list (all_passes);
 729
 730   bitmap_obstack_release (&reg_obstack);
 731
 732   /* Release the default bitmap obstack.  */
 733   bitmap_obstack_release (NULL);
 734
 735   /* Restore original body if still needed.  */
 736   if (cfun->saved_tree)
 737     {
 738       DECL_SAVED_TREE (fndecl) = cfun->saved_tree;
 739       DECL_ARGUMENTS (fndecl) = cfun->saved_args;
 740       cfun->static_chain_decl = cfun->saved_static_chain_decl;
 741
 742       /* When not in unit-at-a-time mode, we must preserve out of line copy
 743          representing node before inlining.  Restore original outgoing edges
 744          using clone we created earlier.  */
 745       if (!flag_unit_at_a_time)
 746         {
 747           struct cgraph_edge *e;
 748
 749           cgraph_node_remove_callees (node);
 750           node->callees = saved_node->callees;
 751           saved_node->callees = NULL;
 752           update_inlined_to_pointers (node, node);
 753           for (e = node->callees; e; e = e->next_callee)
 754             e->caller = node;
 755           cgraph_remove_node (saved_node);
 756         }
 757     }
 758   else
 759     DECL_SAVED_TREE (fndecl) = NULL;
 760   cfun = 0;
 761
 762   /* If requested, warn about function definitions where the function will
 763      return a value (usually of some struct or union type) which itself will
 764      take up a lot of stack space.  */
 765   if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
 766     {
 767       tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
 768
 769       if (ret_type && TYPE_SIZE_UNIT (ret_type)
 770           && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
 771           && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
 772                                    larger_than_size))
 773         {
 774           unsigned int size_as_int
 775             = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
 776
 777           if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
 778             warning (0, "%Jsize of return value of %qD is %u bytes",
 779                      fndecl, fndecl, size_as_int);
 780           else
 781             warning (0, "%Jsize of return value of %qD is larger than %wd bytes",
 782                      fndecl, fndecl, larger_than_size);
 783         }
 784     }
 785
 786   if (!flag_inline_trees)
 787     {
 788       DECL_SAVED_TREE (fndecl) = NULL;
 789       if (DECL_STRUCT_FUNCTION (fndecl) == 0
 790           && !cgraph_node (fndecl)->origin)
 791         {
 792           /* Stop pointing to the local nodes about to be freed.
 793              But DECL_INITIAL must remain nonzero so we know this
 794              was an actual function definition.
 795              For a nested function, this is done in c_pop_function_context.
 796              If rest_of_compilation set this to 0, leave it 0.  */
 797           if (DECL_INITIAL (fndecl) != 0)
 798             DECL_INITIAL (fndecl) = error_mark_node;
 799         }
 800     }
 801
 802   input_location = saved_loc;
 803
 804   ggc_collect ();
 805   timevar_pop (TV_EXPAND);
 806 }