1 /* Data and Control Flow Analysis for Trees.
2 Copyright (C) 2001, 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, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
23 #define _TREE_FLOW_H 1
26 #include "hard-reg-set.h"
27 #include "basic-block.h"
29 #include "tree-gimple.h"
30 #include "tree-ssa-operands.h"
32 #include "ipa-reference.h"
34 /* Forward declare structures for the garbage collector GTY markers. */
35 #ifndef GCC_BASIC_BLOCK_H
37 typedef struct edge_def *edge;
38 struct basic_block_def;
39 typedef struct basic_block_def *basic_block;
42 /* True if the code is in ssa form. */
52 /* Iterate through the elements of hashtable HTAB, using htab_iterator ITER,
53 storing each element in RESULT, which is of type TYPE. */
54 #define FOR_EACH_HTAB_ELEMENT(HTAB, RESULT, TYPE, ITER) \
55 for (RESULT = (TYPE) first_htab_element (&(ITER), (HTAB)); \
56 !end_htab_p (&(ITER)); \
57 RESULT = (TYPE) next_htab_element (&(ITER)))
59 /*---------------------------------------------------------------------------
60 Attributes for SSA_NAMEs.
62 NOTE: These structures are stored in struct tree_ssa_name
63 but are only used by the tree optimizers, so it makes better sense
64 to declare them here to avoid recompiling unrelated files when
66 ---------------------------------------------------------------------------*/
68 /* Aliasing information for SSA_NAMEs representing pointer variables. */
69 struct ptr_info_def GTY(())
71 /* Nonzero if points-to analysis couldn't determine where this pointer
73 unsigned int pt_anything : 1;
75 /* Nonzero if the value of this pointer escapes the current function. */
76 unsigned int value_escapes_p : 1;
78 /* Nonzero if this pointer is dereferenced. */
79 unsigned int is_dereferenced : 1;
81 /* Nonzero if this pointer points to a global variable. */
82 unsigned int pt_global_mem : 1;
84 /* Nonzero if this pointer points to NULL. */
85 unsigned int pt_null : 1;
87 /* Set of variables that this pointer may point to. */
90 /* If this pointer has been dereferenced, and points-to information is
91 more precise than type-based aliasing, indirect references to this
92 pointer will be represented by this memory tag, instead of the type
93 tag computed by TBAA. */
96 /* Mask of reasons this pointer's value escapes the function */
97 unsigned int escape_mask;
101 /*---------------------------------------------------------------------------
102 Tree annotations stored in tree_common.ann
103 ---------------------------------------------------------------------------*/
104 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, FUNCTION_ANN, STMT_ANN };
106 struct tree_ann_common_d GTY(())
108 /* Annotation type. */
109 enum tree_ann_type type;
111 /* Auxiliary info specific to a pass. At all times, this
112 should either point to valid data or be NULL. */
113 PTR GTY ((skip (""))) aux;
115 /* The value handle for this expression. Used by GVN-PRE. */
116 tree GTY((skip)) value_handle;
119 /* It is advantageous to avoid things like life analysis for variables which
120 do not need PHI nodes. This enum describes whether or not a particular
121 variable may need a PHI node. */
123 enum need_phi_state {
124 /* This is the default. If we are still in this state after finding
125 all the definition and use sites, then we will assume the variable
126 needs PHI nodes. This is probably an overly conservative assumption. */
127 NEED_PHI_STATE_UNKNOWN,
129 /* This state indicates that we have seen one or more sets of the
130 variable in a single basic block and that the sets dominate all
131 uses seen so far. If after finding all definition and use sites
132 we are still in this state, then the variable does not need any
136 /* This state indicates that we have either seen multiple definitions of
137 the variable in multiple blocks, or that we encountered a use in a
138 block that was not dominated by the block containing the set(s) of
139 this variable. This variable is assumed to need PHI nodes. */
144 typedef struct subvar *subvar_t;
146 /* This structure represents a fake sub-variable for a structure field. */
147 struct subvar GTY(())
152 /* Next subvar for this structure. */
156 struct var_ann_d GTY(())
158 struct tree_ann_common_d common;
160 /* Used by the out of SSA pass to determine whether this variable has
161 been seen yet or not. */
162 unsigned out_of_ssa_tag : 1;
164 /* Used when building root_var structures in tree_ssa_live.[ch]. */
165 unsigned root_var_processed : 1;
167 /* Nonzero if this variable is in the alias set of another variable. */
168 unsigned is_aliased : 1;
170 /* Nonzero if this variable was used after SSA optimizations were
171 applied. We set this when translating out of SSA form. */
174 /* This field indicates whether or not the variable may need PHI nodes.
175 See the enum's definition for more detailed information about the
177 ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
179 /* Used during operand processing to determine if this variable is already
181 unsigned in_vuse_list : 1;
183 /* Used during operand processing to determine if this variable is already
184 in the v_may_def list. */
185 unsigned in_v_may_def_list : 1;
187 /* An artificial variable representing the memory location pointed-to by
188 all the pointer symbols that flow-insensitive alias analysis
189 (mostly type-based) considers to be aliased. If the variable is
190 not a pointer or if it is never dereferenced, this must be NULL. */
193 /* Variables that may alias this variable. */
194 VEC(tree, gc) *may_aliases;
196 /* Used when going out of SSA form to indicate which partition this
197 variable represents storage for. */
200 /* Used by the root-var object in tree-ssa-live.[ch]. */
203 /* During into-ssa and the dominator optimizer, this field holds the
204 current version of this variable (an SSA_NAME). */
207 /* If this variable is a structure, this fields holds a list of
208 symbols representing each of the fields of the structure. */
211 /* Mask of values saying the reasons why this variable has escaped
213 unsigned int escape_mask;
216 struct function_ann_d GTY(())
218 struct tree_ann_common_d common;
220 /* Pointer to the structure that contains the sets of global
221 variables modified by function calls. This field is only used
222 for FUNCTION_DECLs. */
223 ipa_reference_vars_info_t GTY ((skip)) reference_vars_info;
226 typedef struct immediate_use_iterator_d
228 ssa_use_operand_t *imm_use;
229 ssa_use_operand_t *end_p;
230 ssa_use_operand_t iter_node;
234 /* Use this iterator when simply looking at stmts. Adding, deleting or
235 modifying stmts will cause this iterator to malfunction. */
237 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR) \
238 for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR)); \
239 !end_readonly_imm_use_p (&(ITER)); \
240 (DEST) = next_readonly_imm_use (&(ITER)))
243 #define FOR_EACH_IMM_USE_SAFE(DEST, ITER, SSAVAR) \
244 for ((DEST) = first_safe_imm_use (&(ITER), (SSAVAR)); \
245 !end_safe_imm_use_p (&(ITER)); \
246 (DEST) = next_safe_imm_use (&(ITER)))
248 #define BREAK_FROM_SAFE_IMM_USE(ITER) \
250 end_safe_imm_use_traverse (&(ITER)); \
254 struct stmt_ann_d GTY(())
256 struct tree_ann_common_d common;
258 /* Nonzero if the statement has been modified (meaning that the operands
259 need to be scanned again). */
260 unsigned modified : 1;
262 /* Nonzero if the statement makes references to volatile storage. */
263 unsigned has_volatile_ops : 1;
265 /* Nonzero if the statement makes a function call that may clobber global
266 and local addressable variables. */
267 unsigned makes_clobbering_call : 1;
269 /* Basic block that contains this statement. */
272 /* Operand cache for stmt. */
273 struct stmt_operands_d GTY ((skip (""))) operands;
275 /* Set of variables that have had their address taken in the statement. */
276 bitmap addresses_taken;
278 /* Unique identifier for this statement. These ID's are to be created
279 by each pass on an as-needed basis in any order convenient for the
280 pass which needs statement UIDs. */
283 /* Linked list of histograms for value-based profiling. This is really a
284 struct histogram_value*. We use void* to avoid having to export that
285 everywhere, and to avoid having to put it in GC memory. */
287 void * GTY ((skip (""))) histograms;
290 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
292 struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
293 struct var_ann_d GTY((tag ("VAR_ANN"))) vdecl;
294 struct function_ann_d GTY((tag ("FUNCTION_ANN"))) fdecl;
295 struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
298 extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
300 typedef union tree_ann_d *tree_ann_t;
301 typedef struct var_ann_d *var_ann_t;
302 typedef struct function_ann_d *function_ann_t;
303 typedef struct stmt_ann_d *stmt_ann_t;
305 static inline tree_ann_t tree_ann (tree);
306 static inline tree_ann_t get_tree_ann (tree);
307 static inline var_ann_t var_ann (tree);
308 static inline var_ann_t get_var_ann (tree);
309 static inline function_ann_t function_ann (tree);
310 static inline function_ann_t get_function_ann (tree);
311 static inline stmt_ann_t stmt_ann (tree);
312 static inline stmt_ann_t get_stmt_ann (tree);
313 static inline enum tree_ann_type ann_type (tree_ann_t);
314 static inline basic_block bb_for_stmt (tree);
315 extern void set_bb_for_stmt (tree, basic_block);
316 static inline bool noreturn_call_p (tree);
317 static inline void update_stmt (tree);
318 static inline bool stmt_modified_p (tree);
319 static inline VEC(tree, gc) *may_aliases (tree);
320 static inline int get_lineno (tree);
321 static inline const char *get_filename (tree);
322 static inline bool is_exec_stmt (tree);
323 static inline bool is_label_stmt (tree);
324 static inline bitmap addresses_taken (tree);
326 /*---------------------------------------------------------------------------
327 Structure representing predictions in tree level.
328 ---------------------------------------------------------------------------*/
329 struct edge_prediction GTY((chain_next ("%h.ep_next")))
331 struct edge_prediction *ep_next;
333 enum br_predictor ep_predictor;
337 /* Accessors for basic block annotations. */
338 static inline tree phi_nodes (basic_block);
339 static inline void set_phi_nodes (basic_block, tree);
341 /*---------------------------------------------------------------------------
343 ---------------------------------------------------------------------------*/
344 struct int_tree_map GTY(())
351 extern unsigned int int_tree_map_hash (const void *);
352 extern int int_tree_map_eq (const void *, const void *);
357 } referenced_var_iterator;
360 /* This macro loops over all the referenced vars, one at a time, putting the
361 current var in VAR. Note: You are not allowed to add referenced variables
362 to the hashtable while using this macro. Doing so may cause it to behave
365 #define FOR_EACH_REFERENCED_VAR(VAR, ITER) \
366 for ((VAR) = first_referenced_var (&(ITER)); \
367 !end_referenced_vars_p (&(ITER)); \
368 (VAR) = next_referenced_var (&(ITER)))
374 } safe_referenced_var_iterator;
376 /* This macro loops over all the referenced vars, one at a time, putting the
377 current var in VAR. You are allowed to add referenced variables during the
378 execution of this macro, however, the macro will not iterate over them. It
379 requires a temporary vector of trees, VEC, whose lifetime is controlled by
380 the caller. The purpose of the vector is to temporarily store the
381 referenced_variables hashtable so that adding referenced variables does not
382 affect the hashtable. */
384 #define FOR_EACH_REFERENCED_VAR_SAFE(VAR, VEC, ITER) \
385 for ((ITER).i = 0, fill_referenced_var_vec (&(VEC)); \
386 VEC_iterate (tree, (VEC), (ITER).i, (VAR)); \
389 /* Array of all variables referenced in the function. */
390 extern GTY((param_is (struct int_tree_map))) htab_t referenced_vars;
392 /* Default defs for undefined symbols. */
393 extern GTY((param_is (struct int_tree_map))) htab_t default_defs;
395 extern tree referenced_var_lookup (unsigned int);
396 extern tree referenced_var_lookup_if_exists (unsigned int);
397 #define num_referenced_vars htab_elements (referenced_vars)
398 #define referenced_var(i) referenced_var_lookup (i)
400 /* Array of all SSA_NAMEs used in the function. */
401 extern GTY(()) VEC(tree,gc) *ssa_names;
403 #define num_ssa_names (VEC_length (tree, ssa_names))
404 #define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
406 /* Artificial variable used to model the effects of function calls. */
407 extern GTY(()) tree global_var;
409 /* Call clobbered variables in the function. If bit I is set, then
410 REFERENCED_VARS (I) is call-clobbered. */
411 extern bitmap call_clobbered_vars;
413 /* Addressable variables in the function. If bit I is set, then
414 REFERENCED_VARS (I) has had its address taken. */
415 extern bitmap addressable_vars;
417 /* 'true' after aliases have been computed (see compute_may_aliases). */
418 extern bool aliases_computed_p;
420 /* Macros for showing usage statistics. */
421 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
423 : ((x) < 1024*1024*10 \
425 : (x) / (1024*1024))))
427 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
429 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
431 /*---------------------------------------------------------------------------
433 ---------------------------------------------------------------------------*/
436 tree_stmt_iterator tsi;
438 } block_stmt_iterator;
440 static inline block_stmt_iterator bsi_start (basic_block);
441 static inline block_stmt_iterator bsi_last (basic_block);
442 static inline block_stmt_iterator bsi_after_labels (basic_block);
443 block_stmt_iterator bsi_for_stmt (tree);
444 static inline bool bsi_end_p (block_stmt_iterator);
445 static inline void bsi_next (block_stmt_iterator *);
446 static inline void bsi_prev (block_stmt_iterator *);
447 static inline tree bsi_stmt (block_stmt_iterator);
448 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
450 extern void bsi_remove (block_stmt_iterator *, bool);
451 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
452 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
453 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
455 enum bsi_iterator_update
457 /* Note that these are intentionally in the same order as TSI_FOO. They
458 mean exactly the same as their TSI_* counterparts. */
466 extern void bsi_insert_before (block_stmt_iterator *, tree,
467 enum bsi_iterator_update);
468 extern void bsi_insert_after (block_stmt_iterator *, tree,
469 enum bsi_iterator_update);
471 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
473 /*---------------------------------------------------------------------------
475 ---------------------------------------------------------------------------*/
478 /* Location to track pending stmt for edge insertion. */
479 #define PENDING_STMT(e) ((e)->insns.t)
481 extern void delete_tree_cfg_annotations (void);
482 extern void disband_implicit_edges (void);
483 extern bool stmt_ends_bb_p (tree);
484 extern bool is_ctrl_stmt (tree);
485 extern bool is_ctrl_altering_stmt (tree);
486 extern bool computed_goto_p (tree);
487 extern bool simple_goto_p (tree);
488 extern basic_block single_noncomplex_succ (basic_block bb);
489 extern void tree_dump_bb (basic_block, FILE *, int);
490 extern void debug_tree_bb (basic_block);
491 extern basic_block debug_tree_bb_n (int);
492 extern void dump_tree_cfg (FILE *, int);
493 extern void debug_tree_cfg (int);
494 extern void dump_cfg_stats (FILE *);
495 extern void debug_cfg_stats (void);
496 extern void debug_loop_ir (void);
497 extern void print_loop_ir (FILE *);
498 extern void cleanup_dead_labels (void);
499 extern void group_case_labels (void);
500 extern tree first_stmt (basic_block);
501 extern tree last_stmt (basic_block);
502 extern tree *last_stmt_ptr (basic_block);
503 extern tree last_and_only_stmt (basic_block);
504 extern edge find_taken_edge (basic_block, tree);
505 extern basic_block label_to_block_fn (struct function *, tree);
506 #define label_to_block(t) (label_to_block_fn (cfun, t))
507 extern void bsi_insert_on_edge (edge, tree);
508 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
509 extern void bsi_commit_one_edge_insert (edge, basic_block *);
510 extern void bsi_commit_edge_inserts (void);
511 extern void notice_special_calls (tree);
512 extern void clear_special_calls (void);
513 extern void verify_stmts (void);
514 extern tree tree_block_label (basic_block);
515 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
516 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
518 extern void add_phi_args_after_copy_bb (basic_block);
519 extern void add_phi_args_after_copy (basic_block *, unsigned);
520 extern bool tree_purge_dead_eh_edges (basic_block);
521 extern bool tree_purge_all_dead_eh_edges (bitmap);
522 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
523 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
525 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
527 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
528 tree, tree, tree, tree);
529 extern void init_empty_tree_cfg (void);
530 extern void fold_cond_expr_cond (void);
531 extern void replace_uses_by (tree, tree);
532 extern void start_recording_case_labels (void);
533 extern void end_recording_case_labels (void);
534 extern basic_block move_sese_region_to_fn (struct function *, basic_block,
537 /* In tree-cfgcleanup.c */
538 extern bool cleanup_tree_cfg (void);
539 extern void cleanup_tree_cfg_loop (void);
541 /* In tree-pretty-print.c. */
542 extern void dump_generic_bb (FILE *, basic_block, int, int);
545 extern var_ann_t create_var_ann (tree);
546 extern function_ann_t create_function_ann (tree);
547 extern stmt_ann_t create_stmt_ann (tree);
548 extern tree_ann_t create_tree_ann (tree);
549 extern void dump_dfa_stats (FILE *);
550 extern void debug_dfa_stats (void);
551 extern void debug_referenced_vars (void);
552 extern void dump_referenced_vars (FILE *);
553 extern void dump_variable (FILE *, tree);
554 extern void debug_variable (tree);
555 extern void dump_subvars_for (FILE *, tree);
556 extern void debug_subvars_for (tree);
557 extern tree get_virtual_var (tree);
558 extern void add_referenced_tmp_var (tree);
559 extern void mark_new_vars_to_rename (tree);
560 extern void find_new_referenced_vars (tree *);
562 extern tree make_rename_temp (tree, const char *);
563 extern void set_default_def (tree, tree);
564 extern tree default_def (tree);
565 extern tree default_def_fn (struct function *, tree);
567 /* In tree-phinodes.c */
568 extern void reserve_phi_args_for_new_edge (basic_block);
569 extern tree create_phi_node (tree, basic_block);
570 extern void add_phi_arg (tree, tree, edge);
571 extern void remove_phi_args (edge);
572 extern void remove_phi_node (tree, tree);
573 extern tree phi_reverse (tree);
575 /* In gimple-low.c */
576 extern void record_vars_into (tree, tree);
577 extern void record_vars (tree);
578 extern bool block_may_fallthru (tree);
580 /* In tree-ssa-alias.c */
581 extern void dump_may_aliases_for (FILE *, tree);
582 extern void debug_may_aliases_for (tree);
583 extern void dump_alias_info (FILE *);
584 extern void debug_alias_info (void);
585 extern void dump_points_to_info (FILE *);
586 extern void debug_points_to_info (void);
587 extern void dump_points_to_info_for (FILE *, tree);
588 extern void debug_points_to_info_for (tree);
589 extern bool may_be_aliased (tree);
590 extern bool is_aliased_with (tree, tree);
591 extern struct ptr_info_def *get_ptr_info (tree);
592 extern void add_type_alias (tree, tree);
593 extern void new_type_alias (tree, tree);
594 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
595 static inline subvar_t get_subvars_for_var (tree);
596 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
597 static inline bool ref_contains_array_ref (tree);
598 static inline bool array_ref_contains_indirect_ref (tree);
599 extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
600 HOST_WIDE_INT *, HOST_WIDE_INT *);
601 static inline bool var_can_have_subvars (tree);
602 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
603 unsigned HOST_WIDE_INT,
606 /* Call-back function for walk_use_def_chains(). At each reaching
607 definition, a function with this prototype is called. */
608 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
612 extern void init_tree_ssa (void);
613 extern edge ssa_redirect_edge (edge, basic_block);
614 extern void flush_pending_stmts (edge);
615 extern bool tree_ssa_useless_type_conversion (tree);
616 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
617 extern void verify_ssa (bool);
618 extern void delete_tree_ssa (void);
619 extern void register_new_def (tree, VEC(tree,heap) **);
620 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
621 extern bool stmt_references_memory_p (tree);
623 /* In tree-into-ssa.c */
624 void update_ssa (unsigned);
625 void delete_update_ssa (void);
626 void register_new_name_mapping (tree, tree);
627 tree create_new_def_for (tree, tree, def_operand_p);
628 bool need_ssa_update_p (void);
629 bool name_registered_for_update_p (tree);
630 bitmap ssa_names_to_replace (void);
631 void release_ssa_name_after_update_ssa (tree name);
632 void compute_global_livein (bitmap, bitmap);
633 tree duplicate_ssa_name (tree, tree);
634 void mark_sym_for_renaming (tree);
635 void mark_set_for_renaming (bitmap);
636 tree get_current_def (tree);
637 void set_current_def (tree, tree);
639 /* In tree-ssa-ccp.c */
640 bool fold_stmt (tree *);
641 bool fold_stmt_inplace (tree);
642 tree widen_bitfield (tree, tree, tree);
645 tree vrp_evaluate_conditional (tree, bool);
646 void simplify_stmt_using_ranges (tree);
648 /* In tree-ssa-dom.c */
649 extern void dump_dominator_optimization_stats (FILE *);
650 extern void debug_dominator_optimization_stats (void);
651 int loop_depth_of_name (tree);
653 /* In tree-ssa-copy.c */
654 extern void merge_alias_info (tree, tree);
655 extern void propagate_value (use_operand_p, tree);
656 extern void propagate_tree_value (tree *, tree);
657 extern void replace_exp (use_operand_p, tree);
658 extern bool may_propagate_copy (tree, tree);
659 extern bool may_propagate_copy_into_asm (tree);
665 /* Iv = BASE + STEP * i. */
668 /* True if this iv does not overflow. */
672 /* Description of number of iterations of a loop. All the expressions inside
673 the structure can be evaluated at the end of the loop's preheader
674 (and due to ssa form, also anywhere inside the body of the loop). */
676 struct tree_niter_desc
678 tree assumptions; /* The boolean expression. If this expression evaluates
679 to false, then the other fields in this structure
680 should not be used; there is no guarantee that they
682 tree may_be_zero; /* The boolean expression. If it evaluates to true,
683 the loop will exit in the first iteration (i.e.
684 its latch will not be executed), even if the niter
685 field says otherwise. */
686 tree niter; /* The expression giving the number of iterations of
687 a loop (provided that assumptions == true and
688 may_be_zero == false), more precisely the number
689 of executions of the latch of the loop. */
690 tree additional_info; /* The boolean expression. Sometimes we use additional
691 knowledge to simplify the other expressions
692 contained in this structure (for example the
693 knowledge about value ranges of operands on entry to
694 the loop). If this is a case, conjunction of such
695 condition is stored in this field, so that we do not
696 lose the information: for example if may_be_zero
697 is (n <= 0) and niter is (unsigned) n, we know
698 that the number of iterations is at most
699 MAX_SIGNED_INT. However if the (n <= 0) assumption
700 is eliminated (by looking at the guard on entry of
701 the loop), then the information would be lost. */
703 /* The simplified shape of the exit condition. The loop exits if
704 CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
705 LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
706 LE_EXPR and negative if CMP is GE_EXPR. This information is used
707 by loop unrolling. */
713 /* In tree-vectorizer.c */
714 void vectorize_loops (struct loops *);
716 /* In tree-ssa-phiopt.c */
717 bool empty_block_p (basic_block);
719 /* In tree-ssa-loop*.c */
721 void tree_ssa_lim (struct loops *);
722 void tree_ssa_unswitch_loops (struct loops *);
723 void canonicalize_induction_variables (struct loops *);
724 void tree_unroll_loops_completely (struct loops *, bool);
725 void tree_ssa_prefetch_arrays (struct loops *);
726 void remove_empty_loops (struct loops *);
727 void tree_ssa_iv_optimize (struct loops *);
729 bool number_of_iterations_exit (struct loop *, edge,
730 struct tree_niter_desc *niter, bool);
731 tree find_loop_niter (struct loop *, edge *);
732 tree loop_niter_by_eval (struct loop *, edge);
733 tree find_loop_niter_by_eval (struct loop *, edge *);
734 void estimate_numbers_of_iterations (struct loops *);
735 bool scev_probably_wraps_p (tree, tree, tree, tree, struct loop *, bool *,
737 tree convert_step (struct loop *, tree, tree, tree, tree);
738 void free_numbers_of_iterations_estimates (struct loops *);
739 void free_numbers_of_iterations_estimates_loop (struct loop *);
740 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
741 void verify_loop_closed_ssa (void);
742 void loop_commit_inserts (void);
743 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
744 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
746 void split_loop_exit_edge (edge);
747 void compute_phi_arg_on_exit (edge, tree, tree);
748 unsigned force_expr_to_var_cost (tree);
749 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
750 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
752 basic_block ip_end_pos (struct loop *);
753 basic_block ip_normal_pos (struct loop *);
754 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
755 unsigned int, sbitmap,
757 unsigned int *, int);
758 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
760 tree expand_simple_operations (tree);
761 void substitute_in_loop_info (struct loop *, tree, tree);
762 edge single_dom_exit (struct loop *);
763 bool can_unroll_loop_p (struct loop *loop, unsigned factor,
764 struct tree_niter_desc *niter);
765 void tree_unroll_loop (struct loops *, struct loop *, unsigned,
766 edge, struct tree_niter_desc *);
768 /* In tree-ssa-threadedge.c */
769 extern bool potentially_threadable_block (basic_block);
770 extern void thread_across_edge (tree, edge, bool,
771 VEC(tree, heap) **, tree (*) (tree));
773 /* In tree-ssa-loop-im.c */
774 /* The possibilities of statement movement. */
778 MOVE_IMPOSSIBLE, /* No movement -- side effect expression. */
779 MOVE_PRESERVE_EXECUTION, /* Must not cause the non-executed statement
780 become executed -- memory accesses, ... */
781 MOVE_POSSIBLE /* Unlimited movement. */
783 extern enum move_pos movement_possibility (tree);
785 /* The reasons a variable may escape a function. */
788 NO_ESCAPE = 0, /* Doesn't escape. */
789 ESCAPE_STORED_IN_GLOBAL = 1 << 1,
790 ESCAPE_TO_ASM = 1 << 2, /* Passed by address to an assembly
792 ESCAPE_TO_CALL = 1 << 3, /* Escapes to a function call. */
793 ESCAPE_BAD_CAST = 1 << 4, /* Cast from pointer to integer */
794 ESCAPE_TO_RETURN = 1 << 5, /* Returned from function. */
795 ESCAPE_TO_PURE_CONST = 1 << 6, /* Escapes to a pure or constant
797 ESCAPE_IS_GLOBAL = 1 << 7, /* Is a global variable. */
798 ESCAPE_IS_PARM = 1 << 8, /* Is an incoming function parameter. */
799 ESCAPE_UNKNOWN = 1 << 9 /* We believe it escapes for some reason
800 not enumerated above. */
803 /* In tree-flow-inline.h */
804 static inline bool is_call_clobbered (tree);
805 static inline void mark_call_clobbered (tree, unsigned int);
806 static inline void set_is_used (tree);
807 static inline bool unmodifiable_var_p (tree);
810 extern void make_eh_edges (tree);
811 extern bool tree_could_trap_p (tree);
812 extern bool tree_could_throw_p (tree);
813 extern bool tree_can_throw_internal (tree);
814 extern bool tree_can_throw_external (tree);
815 extern int lookup_stmt_eh_region (tree);
816 extern void add_stmt_to_eh_region (tree, int);
817 extern bool remove_stmt_from_eh_region (tree);
818 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
820 /* In tree-ssa-pre.c */
821 void add_to_value (tree, tree);
822 void debug_value_expressions (tree);
823 void print_value_expressions (FILE *, tree);
827 bool expressions_equal_p (tree, tree);
828 tree get_value_handle (tree);
829 hashval_t vn_compute (tree, hashval_t);
830 void sort_vuses (VEC (tree, gc) *);
831 tree vn_lookup_or_add (tree, tree);
832 tree vn_lookup_or_add_with_vuses (tree, VEC (tree, gc) *);
833 void vn_add (tree, tree);
834 void vn_add_with_vuses (tree, tree, VEC (tree, gc) *);
835 tree vn_lookup (tree, tree);
836 tree vn_lookup_with_vuses (tree, VEC (tree, gc) *);
838 void vn_delete (void);
840 /* In tree-ssa-sink.c */
841 bool is_hidden_global_store (tree);
844 void insert_edge_copies (tree, basic_block);
845 void sra_insert_before (block_stmt_iterator *, tree);
846 void sra_insert_after (block_stmt_iterator *, tree);
847 void sra_init_cache (void);
848 bool sra_type_can_be_decomposed_p (tree);
850 /* In tree-loop-linear.c */
851 extern void linear_transform_loops (struct loops *);
853 /* In tree-ssa-loop-ivopts.c */
854 bool expr_invariant_in_loop_p (struct loop *, tree);
855 bool multiplier_allowed_in_address_p (HOST_WIDE_INT);
856 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode);
858 /* In tree-ssa-threadupdate.c. */
859 extern bool thread_through_all_blocks (void);
860 extern void register_jump_thread (edge, edge);
863 tree force_gimple_operand (tree, tree *, bool, tree);
864 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
866 /* In tree-ssa-structalias.c */
867 bool find_what_p_points_to (tree);
869 /* In tree-ssa-live.c */
870 extern void remove_unused_locals (void);
872 /* In tree-ssa-address.c */
874 /* Affine combination of trees. We keep track of at most MAX_AFF_ELTS elements
875 to make things simpler; this is sufficient in most cases. */
877 #define MAX_AFF_ELTS 8
879 struct affine_tree_combination
881 /* Type of the result of the combination. */
884 /* Mask modulo that the operations are performed. */
885 unsigned HOST_WIDE_INT mask;
887 /* Constant offset. */
888 unsigned HOST_WIDE_INT offset;
890 /* Number of elements of the combination. */
893 /* Elements and their coefficients. */
894 tree elts[MAX_AFF_ELTS];
895 unsigned HOST_WIDE_INT coefs[MAX_AFF_ELTS];
897 /* Remainder of the expression. */
901 /* Description of a memory address. */
905 tree symbol, base, index, step, offset;
908 tree create_mem_ref (block_stmt_iterator *, tree,
909 struct affine_tree_combination *);
910 rtx addr_for_mem_ref (struct mem_address *, bool);
911 void get_address_description (tree, struct mem_address *);
912 tree maybe_fold_tmr (tree);
914 /* This structure is simply used during pushing fields onto the fieldstack
915 to track the offset of the field, since bitpos_of_field gives it relative
916 to its immediate containing type, and we want it relative to the ultimate
917 containing object. */
924 HOST_WIDE_INT offset;
926 typedef struct fieldoff fieldoff_s;
928 DEF_VEC_O(fieldoff_s);
929 DEF_VEC_ALLOC_O(fieldoff_s,heap);
930 int push_fields_onto_fieldstack (tree, VEC(fieldoff_s,heap) **,
931 HOST_WIDE_INT, bool *);
932 void sort_fieldstack (VEC(fieldoff_s,heap) *);
934 void init_alias_heapvars (void);
935 void delete_alias_heapvars (void);
937 #include "tree-flow-inline.h"
939 void swap_tree_operands (tree, tree *, tree *);
941 extern void recalculate_used_alone (void);
942 extern bool updating_used_alone;
943 #endif /* _TREE_FLOW_H */