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>
5 This file is part of GCC.
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)
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.
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. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
33 #include "diagnostic.h"
34 #include "basic-block.h"
36 #include "tree-flow.h"
37 #include "tree-dump.h"
40 #include "langhooks.h"
44 #include "tree-inline.h"
45 #include "tree-mudflap.h"
46 #include "tree-pass.h"
52 /* Global variables used to communicate with passes. */
54 bitmap vars_to_rename;
57 /* The root of the compilation pass tree, once constructed. */
58 static struct tree_opt_pass *all_passes;
60 /* Pass: dump the gimplified, inlined, functions. */
62 static struct tree_opt_pass pass_gimple =
69 0, /* static_pass_number */
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 */
79 /* Gate: execute, or not, all of the non-trivial optimizations. */
82 gate_all_optimizations (void)
85 /* Don't bother doing anything if the program has errors. */
86 && !(errorcount || sorrycount));
89 static struct tree_opt_pass pass_all_optimizations =
92 gate_all_optimizations, /* gate */
96 0, /* static_pass_number */
98 0, /* properties_required */
99 0, /* properties_provided */
100 0, /* properties_destroyed */
101 0, /* todo_flags_start */
102 0, /* todo_flags_finish */
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
112 execute_cleanup_cfg_post_optimizing (void)
115 cleanup_dead_labels ();
116 group_case_labels ();
119 static struct tree_opt_pass pass_cleanup_cfg_post_optimizing =
121 "final_cleanup", /* name */
123 execute_cleanup_cfg_post_optimizing, /* execute */
126 0, /* static_pass_number */
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 */
136 /* Pass: do the actions required to finish with tree-ssa optimization
140 execute_free_datastructures (void)
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);
148 /* Emit gotos for implicit jumps. */
149 disband_implicit_edges ();
151 /* Remove the ssa structures. Do it here since this includes statement
152 annotations that need to be intact during disband_implicit_edges. */
155 /* Re-chain the statements from the blocks. */
156 chain = &DECL_SAVED_TREE (current_function_decl);
157 *chain = alloc_stmt_list ();
159 /* And get rid of annotations we no longer need. */
160 delete_tree_cfg_annotations ();
163 static struct tree_opt_pass pass_free_datastructures =
167 execute_free_datastructures, /* execute */
170 0, /* static_pass_number */
172 PROP_cfg, /* properties_required */
173 0, /* properties_provided */
174 0, /* properties_destroyed */
175 0, /* todo_flags_start */
176 0, /* todo_flags_finish */
181 /* Do the actions required to initialize internal data structures used
182 in tree-ssa optimization passes. */
185 execute_init_datastructures (void)
187 /* Allocate hash tables, arrays and other structures. */
191 static struct tree_opt_pass pass_init_datastructures =
195 execute_init_datastructures, /* execute */
198 0, /* static_pass_number */
200 PROP_cfg, /* properties_required */
201 0, /* properties_provided */
202 0, /* properties_destroyed */
203 0, /* todo_flags_start */
204 0, /* todo_flags_finish */
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
213 register_one_dump_file (struct tree_opt_pass *pass, int n)
215 char *dot_name, *flag_name, *glob_name;
218 /* See below in next_pass_1. */
220 if (pass->static_pass_number != -1)
221 sprintf (num, "%d", ((int) pass->static_pass_number < 0
222 ? 1 : pass->static_pass_number));
224 dot_name = concat (".", pass->name, num, NULL);
225 if (pass->properties_provided & PROP_trees)
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);
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);
242 register_dump_files (struct tree_opt_pass *pass, int properties)
250 pass->properties_required = properties;
252 (properties | pass->properties_provided) & ~pass->properties_destroyed;
254 /* Reset the counter when we reach RTL-based passes. */
255 if ((pass->properties_provided ^ pass->properties_required) & PROP_rtl)
263 new_properties = register_dump_files (pass->sub, new_properties);
265 /* If we have a gate, combine the properties that we could have with
266 and without the pass being examined. */
268 properties &= new_properties;
270 properties = new_properties;
272 pass->properties_provided = properties;
274 register_one_dump_file (pass, pass_number);
283 /* Add a pass to the pass list. Duplicate the pass if it's already
286 static struct tree_opt_pass **
287 next_pass_1 (struct tree_opt_pass **list, struct tree_opt_pass *pass)
290 /* A nonzero static_pass_number indicates that the
291 pass is already in the list. */
292 if (pass->static_pass_number)
294 struct tree_opt_pass *new;
296 new = xmalloc (sizeof (*new));
297 memcpy (new, pass, sizeof (*new));
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. */
305 pass->static_pass_number -= 1;
306 new->static_pass_number = -pass->static_pass_number;
313 pass->static_pass_number = -1;
317 return &(*list)->next;
321 /* Construct the pass tree. */
324 init_tree_optimization_passes (void)
326 struct tree_opt_pass **p;
328 #define NEXT_PASS(PASS) (p = next_pass_1 (p, &PASS))
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);
348 p = &pass_all_optimizations.sub;
349 NEXT_PASS (pass_referenced_vars);
350 NEXT_PASS (pass_maybe_create_global_var);
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_redundant_phi);
358 NEXT_PASS (pass_dce);
359 NEXT_PASS (pass_merge_phi);
360 NEXT_PASS (pass_forwprop);
361 NEXT_PASS (pass_phiopt);
362 NEXT_PASS (pass_may_alias);
363 NEXT_PASS (pass_tail_recursion);
365 NEXT_PASS (pass_profile);
366 NEXT_PASS (pass_sra);
367 /* FIXME: SRA may generate arbitrary gimple code, exposing new
368 aliased and call-clobbered variables. As mentioned below,
369 pass_may_alias should be a TODO item. */
370 NEXT_PASS (pass_may_alias);
371 NEXT_PASS (pass_rename_ssa_copies);
372 NEXT_PASS (pass_dominator);
373 NEXT_PASS (pass_redundant_phi);
374 NEXT_PASS (pass_dce);
375 NEXT_PASS (pass_dse);
376 NEXT_PASS (pass_may_alias);
377 NEXT_PASS (pass_forwprop);
378 NEXT_PASS (pass_phiopt);
379 NEXT_PASS (pass_ccp);
380 NEXT_PASS (pass_redundant_phi);
381 NEXT_PASS (pass_fold_builtins);
382 /* FIXME: May alias should a TODO but for 4.0.0,
383 we add may_alias right after fold builtins
384 which can create arbitrary GIMPLE. */
385 NEXT_PASS (pass_may_alias);
386 NEXT_PASS (pass_split_crit_edges);
387 NEXT_PASS (pass_pre);
388 NEXT_PASS (pass_loop);
389 NEXT_PASS (pass_dominator);
390 NEXT_PASS (pass_redundant_phi);
391 /* FIXME: If DCE is not run before checking for uninitialized uses,
392 we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
393 However, this also causes us to misdiagnose cases that should be
394 real warnings (e.g., testsuite/gcc.dg/pr18501.c).
396 To fix the false positives in uninit-5.c, we would have to
397 account for the predicates protecting the set and the use of each
398 variable. Using a representation like Gated Single Assignment
400 NEXT_PASS (pass_late_warn_uninitialized);
401 NEXT_PASS (pass_cd_dce);
402 NEXT_PASS (pass_dse);
403 NEXT_PASS (pass_forwprop);
404 NEXT_PASS (pass_phiopt);
405 NEXT_PASS (pass_tail_calls);
406 NEXT_PASS (pass_rename_ssa_copies);
407 NEXT_PASS (pass_del_ssa);
408 NEXT_PASS (pass_nrv);
409 NEXT_PASS (pass_remove_useless_vars);
410 NEXT_PASS (pass_mark_used_blocks);
411 NEXT_PASS (pass_cleanup_cfg_post_optimizing);
415 NEXT_PASS (pass_loop_init);
416 NEXT_PASS (pass_lim);
417 NEXT_PASS (pass_unswitch);
418 NEXT_PASS (pass_record_bounds);
419 NEXT_PASS (pass_linear_transform);
420 NEXT_PASS (pass_iv_canon);
421 NEXT_PASS (pass_if_conversion);
422 NEXT_PASS (pass_vectorize);
423 NEXT_PASS (pass_complete_unroll);
424 NEXT_PASS (pass_iv_optimize);
425 NEXT_PASS (pass_loop_done);
430 /* Register the passes with the tree dump code. */
431 register_dump_files (all_passes, 0);
434 static void execute_pass_list (struct tree_opt_pass *);
436 static unsigned int last_verified;
439 execute_todo (int properties, unsigned int flags)
441 if (flags & TODO_rename_vars)
443 rewrite_into_ssa (false);
444 bitmap_clear (vars_to_rename);
446 if (flags & TODO_fix_def_def_chains)
448 rewrite_def_def_chains ();
449 bitmap_clear (vars_to_rename);
452 if (flags & TODO_cleanup_cfg)
455 if ((flags & TODO_dump_func) && dump_file)
457 if (properties & PROP_trees)
458 dump_function_to_file (current_function_decl,
459 dump_file, dump_flags);
460 else if (properties & PROP_cfg)
461 print_rtl_with_bb (dump_file, get_insns ());
463 print_rtl (dump_file, get_insns ());
465 /* Flush the file. If verification fails, we won't be able to
466 close the file before aborting. */
470 if (flags & TODO_ggc_collect)
473 #ifdef ENABLE_CHECKING
474 if (flags & TODO_verify_ssa)
476 if (flags & TODO_verify_flow)
478 if (flags & TODO_verify_stmts)
484 execute_one_pass (struct tree_opt_pass *pass)
488 /* See if we're supposed to run this pass. */
489 if (pass->gate && !pass->gate ())
492 /* Note that the folders should only create gimple expressions.
493 This is a hack until the new folder is ready. */
494 in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
496 /* Run pre-pass verification. */
497 todo = pass->todo_flags_start & ~last_verified;
499 execute_todo (pass->properties_required, todo);
501 /* If a dump file name is present, open it if enabled. */
502 if (pass->static_pass_number != -1)
504 bool initializing_dump = !dump_initialized_p (pass->static_pass_number);
505 dump_file_name = get_dump_file_name (pass->static_pass_number);
506 dump_file = dump_begin (pass->static_pass_number, &dump_flags);
509 const char *dname, *aname;
510 dname = lang_hooks.decl_printable_name (current_function_decl, 2);
511 aname = (IDENTIFIER_POINTER
512 (DECL_ASSEMBLER_NAME (current_function_decl)));
513 fprintf (dump_file, "\n;; Function %s (%s)%s\n\n", dname, aname,
514 cfun->function_frequency == FUNCTION_FREQUENCY_HOT
516 : cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
517 ? " (unlikely executed)"
521 if (initializing_dump
522 && graph_dump_format != no_graph
523 && (pass->properties_provided & (PROP_cfg | PROP_rtl))
524 == (PROP_cfg | PROP_rtl))
525 clean_graph_dump_file (dump_file_name);
528 /* If a timevar is present, start it. */
530 timevar_push (pass->tv_id);
538 timevar_pop (pass->tv_id);
541 && (pass->properties_provided & (PROP_cfg | PROP_rtl))
542 == (PROP_cfg | PROP_rtl))
543 print_rtl_with_bb (dump_file, get_insns ());
545 /* Run post-pass cleanup and verification. */
546 todo = pass->todo_flags_finish;
547 last_verified = todo & TODO_verify_all;
549 execute_todo (pass->properties_provided, todo);
551 /* Flush and close dump file. */
554 free ((char *) dump_file_name);
555 dump_file_name = NULL;
559 dump_end (pass->static_pass_number, dump_file);
567 execute_pass_list (struct tree_opt_pass *pass)
571 if (execute_one_pass (pass) && pass->sub)
572 execute_pass_list (pass->sub);
579 /* Update recursively all inlined_to pointers of functions
580 inlined into NODE to INLINED_TO. */
582 update_inlined_to_pointers (struct cgraph_node *node,
583 struct cgraph_node *inlined_to)
585 struct cgraph_edge *e;
586 for (e = node->callees; e; e = e->next_callee)
588 if (e->callee->global.inlined_to)
590 e->callee->global.inlined_to = inlined_to;
591 update_inlined_to_pointers (e->callee, inlined_to);
597 /* For functions-as-trees languages, this performs all optimization and
598 compilation for FNDECL. */
601 tree_rest_of_compilation (tree fndecl)
603 location_t saved_loc;
604 struct cgraph_node *saved_node = NULL, *node;
606 timevar_push (TV_EXPAND);
608 gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);
610 /* Initialize the RTL code for the function. */
611 current_function_decl = fndecl;
612 saved_loc = input_location;
613 input_location = DECL_SOURCE_LOCATION (fndecl);
614 init_function_start (fndecl);
616 /* Even though we're inside a function body, we still don't want to
617 call expand_expr to calculate the size of a variable-sized array.
618 We haven't necessarily assigned RTL to all variables yet, so it's
619 not safe to try to expand expressions involving them. */
620 cfun->x_dont_save_pending_sizes_p = 1;
622 node = cgraph_node (fndecl);
624 /* We might need the body of this function so that we can expand
625 it inline somewhere else. This means not lowering some constructs
626 such as exception handling. */
627 if (cgraph_preserve_function_body_p (fndecl))
629 if (!flag_unit_at_a_time)
631 struct cgraph_edge *e;
633 saved_node = cgraph_clone_node (node);
634 for (e = saved_node->callees; e; e = e->next_callee)
635 if (!e->inline_failed)
636 cgraph_clone_inlined_nodes (e, true);
638 cfun->saved_static_chain_decl = cfun->static_chain_decl;
639 cfun->saved_tree = save_body (fndecl, &cfun->saved_args,
640 &cfun->saved_static_chain_decl);
643 if (flag_inline_trees)
645 struct cgraph_edge *e;
646 for (e = node->callees; e; e = e->next_callee)
647 if (!e->inline_failed || warn_inline)
651 timevar_push (TV_INTEGRATION);
652 optimize_inline_calls (fndecl);
653 timevar_pop (TV_INTEGRATION);
657 /* We are not going to maintain the cgraph edges up to date.
658 Kill it so it won't confuse us. */
659 while (node->callees)
660 cgraph_remove_edge (node->callees);
663 /* Initialize the default bitmap obstack. */
664 bitmap_obstack_initialize (NULL);
665 bitmap_obstack_initialize (®_obstack); /* FIXME, only at RTL generation*/
667 vars_to_rename = BITMAP_ALLOC (NULL);
669 /* Perform all tree transforms and optimizations. */
670 execute_pass_list (all_passes);
672 bitmap_obstack_release (®_obstack);
674 /* Release the default bitmap obstack. */
675 bitmap_obstack_release (NULL);
677 /* Restore original body if still needed. */
678 if (cfun->saved_tree)
680 DECL_SAVED_TREE (fndecl) = cfun->saved_tree;
681 DECL_ARGUMENTS (fndecl) = cfun->saved_args;
682 cfun->static_chain_decl = cfun->saved_static_chain_decl;
684 /* When not in unit-at-a-time mode, we must preserve out of line copy
685 representing node before inlining. Restore original outgoing edges
686 using clone we created earlier. */
687 if (!flag_unit_at_a_time)
689 struct cgraph_edge *e;
691 while (node->callees)
692 cgraph_remove_edge (node->callees);
693 node->callees = saved_node->callees;
694 saved_node->callees = NULL;
695 update_inlined_to_pointers (node, node);
696 for (e = node->callees; e; e = e->next_callee)
698 cgraph_remove_node (saved_node);
702 DECL_SAVED_TREE (fndecl) = NULL;
705 /* If requested, warn about function definitions where the function will
706 return a value (usually of some struct or union type) which itself will
707 take up a lot of stack space. */
708 if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
710 tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
712 if (ret_type && TYPE_SIZE_UNIT (ret_type)
713 && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
714 && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
717 unsigned int size_as_int
718 = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
720 if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
721 warning ("%Jsize of return value of %qD is %u bytes",
722 fndecl, fndecl, size_as_int);
724 warning ("%Jsize of return value of %qD is larger than %wd bytes",
725 fndecl, fndecl, larger_than_size);
729 if (!flag_inline_trees)
731 DECL_SAVED_TREE (fndecl) = NULL;
732 if (DECL_STRUCT_FUNCTION (fndecl) == 0
733 && !cgraph_node (fndecl)->origin)
735 /* Stop pointing to the local nodes about to be freed.
736 But DECL_INITIAL must remain nonzero so we know this
737 was an actual function definition.
738 For a nested function, this is done in c_pop_function_context.
739 If rest_of_compilation set this to 0, leave it 0. */
740 if (DECL_INITIAL (fndecl) != 0)
741 DECL_INITIAL (fndecl) = error_mark_node;
745 input_location = saved_loc;
748 timevar_pop (TV_EXPAND);