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>
6 This file is part of GCC.
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)
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.
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/>. */
24 #include "coretypes.h"
28 #include "basic-block.h"
31 #include "tree-flow.h"
32 #include "tree-dump.h"
35 #include "langhooks.h"
36 #include "diagnostic-core.h"
40 #include "tree-inline.h"
41 #include "tree-mudflap.h"
42 #include "tree-pass.h"
49 #include "regset.h" /* FIXME: For reg_obstack. */
51 /* Gate: execute, or not, all of the non-trivial optimizations. */
54 gate_all_optimizations (void)
57 /* Don't bother doing anything if the program has errors.
58 We have to pass down the queue if we already went into SSA */
59 && (!seen_error () || gimple_in_ssa_p (cfun)));
62 struct gimple_opt_pass pass_all_optimizations =
66 "*all_optimizations", /* name */
67 gate_all_optimizations, /* gate */
71 0, /* static_pass_number */
73 0, /* properties_required */
74 0, /* properties_provided */
75 0, /* properties_destroyed */
76 0, /* todo_flags_start */
77 0 /* todo_flags_finish */
81 /* Gate: execute, or not, all of the non-trivial optimizations. */
84 gate_all_early_local_passes (void)
86 /* Don't bother doing anything if the program has errors. */
87 return (!seen_error () && !in_lto_p);
91 execute_all_early_local_passes (void)
93 /* Once this pass (and its sub-passes) are complete, all functions
94 will be in SSA form. Technically this state change is happening
95 a tad early, since the sub-passes have not yet run, but since
96 none of the sub-passes are IPA passes and do not create new
97 functions, this is ok. We're setting this value for the benefit
98 of IPA passes that follow. */
99 if (cgraph_state < CGRAPH_STATE_IPA_SSA)
100 cgraph_state = CGRAPH_STATE_IPA_SSA;
104 struct simple_ipa_opt_pass pass_early_local_passes =
108 "early_local_cleanups", /* name */
109 gate_all_early_local_passes, /* gate */
110 execute_all_early_local_passes, /* execute */
113 0, /* static_pass_number */
115 0, /* properties_required */
116 0, /* properties_provided */
117 0, /* properties_destroyed */
118 0, /* todo_flags_start */
119 TODO_remove_functions /* todo_flags_finish */
123 /* Gate: execute, or not, all of the non-trivial optimizations. */
126 gate_all_early_optimizations (void)
128 return (optimize >= 1
129 /* Don't bother doing anything if the program has errors. */
133 struct gimple_opt_pass pass_all_early_optimizations =
137 "early_optimizations", /* name */
138 gate_all_early_optimizations, /* gate */
142 0, /* static_pass_number */
144 0, /* properties_required */
145 0, /* properties_provided */
146 0, /* properties_destroyed */
147 0, /* todo_flags_start */
148 0 /* todo_flags_finish */
153 /* Pass: cleanup the CFG just before expanding trees to RTL.
154 This is just a round of label cleanups and case node grouping
155 because after the tree optimizers have run such cleanups may
159 execute_cleanup_cfg_post_optimizing (void)
161 fold_cond_expr_cond ();
163 cleanup_dead_labels ();
164 group_case_labels ();
165 if ((flag_compare_debug_opt || flag_compare_debug)
166 && flag_dump_final_insns)
168 FILE *final_output = fopen (flag_dump_final_insns, "a");
172 error ("could not open final insn dump file %qs: %m",
173 flag_dump_final_insns);
174 flag_dump_final_insns = NULL;
178 int save_unnumbered = flag_dump_unnumbered;
179 int save_noaddr = flag_dump_noaddr;
181 flag_dump_noaddr = flag_dump_unnumbered = 1;
182 fprintf (final_output, "\n");
183 dump_enumerated_decls (final_output, dump_flags | TDF_NOUID);
184 flag_dump_noaddr = save_noaddr;
185 flag_dump_unnumbered = save_unnumbered;
186 if (fclose (final_output))
188 error ("could not close final insn dump file %qs: %m",
189 flag_dump_final_insns);
190 flag_dump_final_insns = NULL;
197 struct gimple_opt_pass pass_cleanup_cfg_post_optimizing =
201 "optimized", /* name */
203 execute_cleanup_cfg_post_optimizing, /* execute */
206 0, /* static_pass_number */
208 PROP_cfg, /* properties_required */
209 0, /* properties_provided */
210 0, /* properties_destroyed */
211 0, /* todo_flags_start */
212 TODO_dump_func /* todo_flags_finish */
213 | TODO_remove_unused_locals
217 /* Pass: do the actions required to finish with tree-ssa optimization
221 execute_free_datastructures (void)
223 free_dominance_info (CDI_DOMINATORS);
224 free_dominance_info (CDI_POST_DOMINATORS);
226 /* And get rid of annotations we no longer need. */
227 delete_tree_cfg_annotations ();
232 /* IPA passes, compilation of earlier functions or inlining
233 might have changed some properties, such as marked functions nothrow,
234 pure, const or noreturn.
235 Remove redundant edges and basic blocks, and create new ones if necessary.
237 This pass can't be executed as stand alone pass from pass manager, because
238 in between inlining and this fixup the verify_flow_info would fail. */
241 execute_fixup_cfg (void)
244 gimple_stmt_iterator gsi;
245 int todo = gimple_in_ssa_p (cfun) ? TODO_verify_ssa : 0;
246 gcov_type count_scale;
250 if (ENTRY_BLOCK_PTR->count)
251 count_scale = (cgraph_node (current_function_decl)->count * REG_BR_PROB_BASE
252 + ENTRY_BLOCK_PTR->count / 2) / ENTRY_BLOCK_PTR->count;
254 count_scale = REG_BR_PROB_BASE;
256 ENTRY_BLOCK_PTR->count = cgraph_node (current_function_decl)->count;
257 EXIT_BLOCK_PTR->count = (EXIT_BLOCK_PTR->count * count_scale
258 + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
262 bb->count = (bb->count * count_scale
263 + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
264 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
266 gimple stmt = gsi_stmt (gsi);
267 tree decl = is_gimple_call (stmt)
268 ? gimple_call_fndecl (stmt)
272 int flags = gimple_call_flags (stmt);
273 if (flags & (ECF_CONST | ECF_PURE | ECF_LOOPING_CONST_OR_PURE))
275 if (gimple_in_ssa_p (cfun))
277 todo |= TODO_update_ssa | TODO_cleanup_cfg;
282 if (flags & ECF_NORETURN
283 && fixup_noreturn_call (stmt))
284 todo |= TODO_cleanup_cfg;
287 if (maybe_clean_eh_stmt (stmt)
288 && gimple_purge_dead_eh_edges (bb))
289 todo |= TODO_cleanup_cfg;
292 FOR_EACH_EDGE (e, ei, bb->succs)
293 e->count = (e->count * count_scale
294 + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
296 if (count_scale != REG_BR_PROB_BASE)
297 compute_function_frequency ();
299 /* We just processed all calls. */
302 VEC_free (gimple, gc, MODIFIED_NORETURN_CALLS (cfun));
303 MODIFIED_NORETURN_CALLS (cfun) = NULL;
306 /* Dump a textual representation of the flowgraph. */
308 gimple_dump_cfg (dump_file, dump_flags);
313 struct gimple_opt_pass pass_fixup_cfg =
317 "*free_cfg_annotations", /* name */
319 execute_fixup_cfg, /* execute */
322 0, /* static_pass_number */
324 PROP_cfg, /* properties_required */
325 0, /* properties_provided */
326 0, /* properties_destroyed */
327 0, /* todo_flags_start */
328 0 /* todo_flags_finish */
332 /* Do the actions required to initialize internal data structures used
333 in tree-ssa optimization passes. */
336 execute_init_datastructures (void)
338 /* Allocate hash tables, arrays and other structures. */
339 init_tree_ssa (cfun);
343 struct gimple_opt_pass pass_init_datastructures =
347 "*init_datastructures", /* name */
349 execute_init_datastructures, /* execute */
352 0, /* static_pass_number */
354 PROP_cfg, /* properties_required */
355 0, /* properties_provided */
356 0, /* properties_destroyed */
357 0, /* todo_flags_start */
358 0 /* todo_flags_finish */
363 tree_lowering_passes (tree fn)
365 tree saved_current_function_decl = current_function_decl;
367 current_function_decl = fn;
368 push_cfun (DECL_STRUCT_FUNCTION (fn));
369 gimple_register_cfg_hooks ();
370 bitmap_obstack_initialize (NULL);
371 execute_pass_list (all_lowering_passes);
372 if (optimize && cgraph_global_info_ready)
373 execute_pass_list (pass_early_local_passes.pass.sub);
374 free_dominance_info (CDI_POST_DOMINATORS);
375 free_dominance_info (CDI_DOMINATORS);
377 current_function_decl = saved_current_function_decl;
378 bitmap_obstack_release (NULL);
382 /* For functions-as-trees languages, this performs all optimization and
383 compilation for FNDECL. */
386 tree_rest_of_compilation (tree fndecl)
388 location_t saved_loc;
390 timevar_push (TV_EXPAND);
392 gcc_assert (cgraph_global_info_ready);
394 /* Initialize the default bitmap obstack. */
395 bitmap_obstack_initialize (NULL);
397 /* Initialize the RTL code for the function. */
398 current_function_decl = fndecl;
399 saved_loc = input_location;
400 input_location = DECL_SOURCE_LOCATION (fndecl);
401 init_function_start (fndecl);
403 /* Even though we're inside a function body, we still don't want to
404 call expand_expr to calculate the size of a variable-sized array.
405 We haven't necessarily assigned RTL to all variables yet, so it's
406 not safe to try to expand expressions involving them. */
407 cfun->dont_save_pending_sizes_p = 1;
409 gimple_register_cfg_hooks ();
411 bitmap_obstack_initialize (®_obstack); /* FIXME, only at RTL generation*/
413 execute_all_ipa_transforms ();
415 /* Perform all tree transforms and optimizations. */
417 /* Signal the start of passes. */
418 invoke_plugin_callbacks (PLUGIN_ALL_PASSES_START, NULL);
420 execute_pass_list (all_passes);
422 /* Signal the end of passes. */
423 invoke_plugin_callbacks (PLUGIN_ALL_PASSES_END, NULL);
425 bitmap_obstack_release (®_obstack);
427 /* Release the default bitmap obstack. */
428 bitmap_obstack_release (NULL);
432 /* If requested, warn about function definitions where the function will
433 return a value (usually of some struct or union type) which itself will
434 take up a lot of stack space. */
435 if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
437 tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
439 if (ret_type && TYPE_SIZE_UNIT (ret_type)
440 && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
441 && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
444 unsigned int size_as_int
445 = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
447 if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
448 warning (OPT_Wlarger_than_, "size of return value of %q+D is %u bytes",
449 fndecl, size_as_int);
451 warning (OPT_Wlarger_than_, "size of return value of %q+D is larger than %wd bytes",
452 fndecl, larger_than_size);
456 gimple_set_body (fndecl, NULL);
457 if (DECL_STRUCT_FUNCTION (fndecl) == 0
458 && !cgraph_node (fndecl)->origin)
460 /* Stop pointing to the local nodes about to be freed.
461 But DECL_INITIAL must remain nonzero so we know this
462 was an actual function definition.
463 For a nested function, this is done in c_pop_function_context.
464 If rest_of_compilation set this to 0, leave it 0. */
465 if (DECL_INITIAL (fndecl) != 0)
466 DECL_INITIAL (fndecl) = error_mark_node;
469 input_location = saved_loc;
472 timevar_pop (TV_EXPAND);