gcc/tree-optimize.c

   1 /* Top-level control of tree optimizations.
   2    Copyright 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "tm_p.h"
  28 #include "basic-block.h"
  29 #include "output.h"
  30 #include "flags.h"
  31 #include "tree-flow.h"
  32 #include "tree-dump.h"
  33 #include "timevar.h"
  34 #include "function.h"
  35 #include "langhooks.h"
  36 #include "diagnostic-core.h"
  37 #include "toplev.h"
  38 #include "flags.h"
  39 #include "cgraph.h"
  40 #include "tree-inline.h"
  41 #include "tree-pass.h"
  42 #include "ggc.h"
  43 #include "cgraph.h"
  44 #include "graph.h"
  45 #include "cfgloop.h"
  46 #include "except.h"
  47 #include "plugin.h"
  48
  49
  50 /* Pass: cleanup the CFG just before expanding trees to RTL.
  51    This is just a round of label cleanups and case node grouping
  52    because after the tree optimizers have run such cleanups may
  53    be necessary.  */
  54
  55 static unsigned int
  56 execute_cleanup_cfg_post_optimizing (void)
  57 {
  58   unsigned int todo = 0;
  59   if (cleanup_tree_cfg ())
  60     todo |= TODO_update_ssa;
  61   maybe_remove_unreachable_handlers ();
  62   cleanup_dead_labels ();
  63   group_case_labels ();
  64   if ((flag_compare_debug_opt || flag_compare_debug)
  65       && flag_dump_final_insns)
  66     {
  67       FILE *final_output = fopen (flag_dump_final_insns, "a");
  68
  69       if (!final_output)
  70         {
  71           error ("could not open final insn dump file %qs: %m",
  72                  flag_dump_final_insns);
  73           flag_dump_final_insns = NULL;
  74         }
  75       else
  76         {
  77           int save_unnumbered = flag_dump_unnumbered;
  78           int save_noaddr = flag_dump_noaddr;
  79
  80           flag_dump_noaddr = flag_dump_unnumbered = 1;
  81           fprintf (final_output, "\n");
  82           dump_enumerated_decls (final_output, dump_flags | TDF_NOUID);
  83           flag_dump_noaddr = save_noaddr;
  84           flag_dump_unnumbered = save_unnumbered;
  85           if (fclose (final_output))
  86             {
  87               error ("could not close final insn dump file %qs: %m",
  88                      flag_dump_final_insns);
  89               flag_dump_final_insns = NULL;
  90             }
  91         }
  92     }
  93   return todo;
  94 }
  95
  96 struct gimple_opt_pass pass_cleanup_cfg_post_optimizing =
  97 {
  98  {
  99   GIMPLE_PASS,
 100   "optimized",                          /* name */
 101   NULL,                                 /* gate */
 102   execute_cleanup_cfg_post_optimizing,  /* execute */
 103   NULL,                                 /* sub */
 104   NULL,                                 /* next */
 105   0,                                    /* static_pass_number */
 106   TV_TREE_CLEANUP_CFG,                  /* tv_id */
 107   PROP_cfg,                             /* properties_required */
 108   0,                                    /* properties_provided */
 109   0,                                    /* properties_destroyed */
 110   0,                                    /* todo_flags_start */
 111   TODO_remove_unused_locals             /* todo_flags_finish */
 112  }
 113 };
 114
 115 /* IPA passes, compilation of earlier functions or inlining
 116    might have changed some properties, such as marked functions nothrow,
 117    pure, const or noreturn.
 118    Remove redundant edges and basic blocks, and create new ones if necessary.
 119
 120    This pass can't be executed as stand alone pass from pass manager, because
 121    in between inlining and this fixup the verify_flow_info would fail.  */
 122
 123 unsigned int
 124 execute_fixup_cfg (void)
 125 {
 126   basic_block bb;
 127   gimple_stmt_iterator gsi;
 128   int todo = gimple_in_ssa_p (cfun) ? TODO_verify_ssa : 0;
 129   gcov_type count_scale;
 130   edge e;
 131   edge_iterator ei;
 132
 133   if (ENTRY_BLOCK_PTR->count)
 134     count_scale = ((cgraph_get_node (current_function_decl)->count
 135                     * REG_BR_PROB_BASE + ENTRY_BLOCK_PTR->count / 2)
 136                    / ENTRY_BLOCK_PTR->count);
 137   else
 138     count_scale = REG_BR_PROB_BASE;
 139
 140   ENTRY_BLOCK_PTR->count = cgraph_get_node (current_function_decl)->count;
 141   EXIT_BLOCK_PTR->count = (EXIT_BLOCK_PTR->count * count_scale
 142                            + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
 143
 144   FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
 145     e->count = (e->count * count_scale
 146        + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
 147
 148   FOR_EACH_BB (bb)
 149     {
 150       bb->count = (bb->count * count_scale
 151                    + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
 152       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 153         {
 154           gimple stmt = gsi_stmt (gsi);
 155           tree decl = is_gimple_call (stmt)
 156                       ? gimple_call_fndecl (stmt)
 157                       : NULL;
 158           if (decl)
 159             {
 160               int flags = gimple_call_flags (stmt);
 161               if (flags & (ECF_CONST | ECF_PURE | ECF_LOOPING_CONST_OR_PURE))
 162                 {
 163                   if (gimple_purge_dead_abnormal_call_edges (bb))
 164                     todo |= TODO_cleanup_cfg;
 165
 166                   if (gimple_in_ssa_p (cfun))
 167                     {
 168                       todo |= TODO_update_ssa | TODO_cleanup_cfg;
 169                       update_stmt (stmt);
 170                     }
 171                 }
 172
 173               if (flags & ECF_NORETURN
 174                   && fixup_noreturn_call (stmt))
 175                 todo |= TODO_cleanup_cfg;
 176              }
 177
 178           if (maybe_clean_eh_stmt (stmt)
 179               && gimple_purge_dead_eh_edges (bb))
 180             todo |= TODO_cleanup_cfg;
 181         }
 182
 183       FOR_EACH_EDGE (e, ei, bb->succs)
 184         e->count = (e->count * count_scale
 185                     + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
 186     }
 187   if (count_scale != REG_BR_PROB_BASE)
 188     compute_function_frequency ();
 189
 190   /* We just processed all calls.  */
 191   if (cfun->gimple_df)
 192     {
 193       VEC_free (gimple, gc, MODIFIED_NORETURN_CALLS (cfun));
 194       MODIFIED_NORETURN_CALLS (cfun) = NULL;
 195     }
 196
 197   /* Dump a textual representation of the flowgraph.  */
 198   if (dump_file)
 199     gimple_dump_cfg (dump_file, dump_flags);
 200
 201   return todo;
 202 }
 203
 204 struct gimple_opt_pass pass_fixup_cfg =
 205 {
 206  {
 207   GIMPLE_PASS,
 208   "*free_cfg_annotations",              /* name */
 209   NULL,                                 /* gate */
 210   execute_fixup_cfg,                    /* execute */
 211   NULL,                                 /* sub */
 212   NULL,                                 /* next */
 213   0,                                    /* static_pass_number */
 214   TV_NONE,                              /* tv_id */
 215   PROP_cfg,                             /* properties_required */
 216   0,                                    /* properties_provided */
 217   0,                                    /* properties_destroyed */
 218   0,                                    /* todo_flags_start */
 219   0                                     /* todo_flags_finish */
 220  }
 221 };