gcc/tree-flow.h

   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>
   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 #ifndef _TREE_FLOW_H
  23 #define _TREE_FLOW_H 1
  24
  25 #include "bitmap.h"
  26 #include "hard-reg-set.h"
  27 #include "basic-block.h"
  28 #include "hashtab.h"
  29 #include "tree-gimple.h"
  30 #include "tree-ssa-operands.h"
  31 #include "cgraph.h"
  32
  33 /* Forward declare structures for the garbage collector GTY markers.  */
  34 #ifndef GCC_BASIC_BLOCK_H
  35 struct edge_def;
  36 typedef struct edge_def *edge;
  37 struct basic_block_def;
  38 typedef struct basic_block_def *basic_block;
  39 #endif
  40
  41 /* True if the code is in ssa form.  */
  42 extern bool in_ssa_p;
  43
  44 /*---------------------------------------------------------------------------
  45                       Attributes for SSA_NAMEs.
  46
  47   NOTE: These structures are stored in struct tree_ssa_name
  48   but are only used by the tree optimizers, so it makes better sense
  49   to declare them here to avoid recompiling unrelated files when
  50   making changes.
  51 ---------------------------------------------------------------------------*/
  52
  53 /* Aliasing information for SSA_NAMEs representing pointer variables.  */
  54 struct ptr_info_def GTY(())
  55 {
  56   /* Nonzero if points-to analysis couldn't determine where this pointer
  57      is pointing to.  */
  58   unsigned int pt_anything : 1;
  59
  60   /* Nonzero if this pointer is the result of a call to malloc.  */
  61   unsigned int pt_malloc : 1;
  62
  63   /* Nonzero if the value of this pointer escapes the current function.  */
  64   unsigned int value_escapes_p : 1;
  65
  66   /* Nonzero if this pointer is dereferenced.  */
  67   unsigned int is_dereferenced : 1;
  68
  69   /* Nonzero if this pointer points to a global variable.  */
  70   unsigned int pt_global_mem : 1;
  71
  72   /* Nonzero if this pointer points to NULL.  */
  73   unsigned int pt_null : 1;
  74
  75   /* Set of variables that this pointer may point to.  */
  76   bitmap pt_vars;
  77
  78   /* If this pointer has been dereferenced, and points-to information is
  79      more precise than type-based aliasing, indirect references to this
  80      pointer will be represented by this memory tag, instead of the type
  81      tag computed by TBAA.  */
  82   tree name_mem_tag;
  83 };
  84
  85
  86 /* Types of value ranges.  */
  87 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
  88
  89
  90 /* Ranges of values that can be associated with an SSA_NAME after VRP
  91    has executed.  */
  92 struct value_range_def GTY(())
  93 {
  94   /* Lattice value represented by this range.  */
  95   enum value_range_type type;
  96
  97   /* Minimum and maximum values represented by this range.  These
  98      values are _CST nodes that should be interpreted as follows:
  99
 100         - If TYPE == VR_UNDEFINED then MIN and MAX must be NULL.
 101
 102         - If TYPE == VR_RANGE then MIN holds the minimum value and
 103           MAX holds the maximum value of the range [MIN, MAX].
 104
 105         - If TYPE == ANTI_RANGE the variable is known to NOT
 106           take any values in the range [MIN, MAX].  */
 107   tree min;
 108   tree max;
 109 };
 110
 111 typedef struct value_range_def value_range;
 112
 113
 114 /*---------------------------------------------------------------------------
 115                    Tree annotations stored in tree_common.ann
 116 ---------------------------------------------------------------------------*/
 117 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, STMT_ANN };
 118
 119 struct tree_ann_common_d GTY(())
 120 {
 121   /* Annotation type.  */
 122   enum tree_ann_type type;
 123
 124   /* The value handle for this expression.  Used by GVN-PRE.  */
 125   tree GTY((skip)) value_handle;
 126 };
 127
 128 /* It is advantageous to avoid things like life analysis for variables which
 129    do not need PHI nodes.  This enum describes whether or not a particular
 130    variable may need a PHI node.  */
 131
 132 enum need_phi_state {
 133   /* This is the default.  If we are still in this state after finding
 134      all the definition and use sites, then we will assume the variable
 135      needs PHI nodes.  This is probably an overly conservative assumption.  */
 136   NEED_PHI_STATE_UNKNOWN,
 137
 138   /* This state indicates that we have seen one or more sets of the
 139      variable in a single basic block and that the sets dominate all
 140      uses seen so far.  If after finding all definition and use sites
 141      we are still in this state, then the variable does not need any
 142      PHI nodes.  */
 143   NEED_PHI_STATE_NO,
 144
 145   /* This state indicates that we have either seen multiple definitions of
 146      the variable in multiple blocks, or that we encountered a use in a
 147      block that was not dominated by the block containing the set(s) of
 148      this variable.  This variable is assumed to need PHI nodes.  */
 149   NEED_PHI_STATE_MAYBE
 150 };
 151
 152
 153 /* When computing aliasing information, we represent the memory pointed-to
 154    by pointers with artificial variables called "memory tags" (MT).  There
 155    are two kinds of tags: type and name.  Type tags (TMT) are used in
 156    type-based alias analysis, they represent all the pointed-to locations
 157    and variables of the same alias set class.  Name tags (NMT) are used in
 158    flow-sensitive points-to alias analysis, they represent the variables
 159    and memory locations pointed-to by a specific SSA_NAME pointer.  */
 160 enum mem_tag_kind {
 161   /* This variable is not a memory tag.  */
 162   NOT_A_TAG,
 163
 164   /* This variable is a type memory tag (TMT).  */
 165   TYPE_TAG,
 166
 167   /* This variable is a name memory tag (NMT).  */
 168   NAME_TAG,
 169
 170   /* This variable represents a structure field.  */
 171   STRUCT_FIELD
 172 };
 173 struct subvar;
 174 typedef struct subvar *subvar_t;
 175
 176 /* This structure represents a fake sub-variable for a structure field.  */
 177
 178 struct subvar GTY(())
 179 {
 180   /* Fake variable name */
 181   tree var;
 182   /* Offset inside structure.  */
 183   HOST_WIDE_INT offset;
 184   /* Size of field.  */
 185   HOST_WIDE_INT size;
 186   /* Next subvar for this structure.  */
 187   subvar_t next;
 188 };
 189
 190 struct var_ann_d GTY(())
 191 {
 192   struct tree_ann_common_d common;
 193
 194   /* Used by the out of SSA pass to determine whether this variable has
 195      been seen yet or not.  */
 196   unsigned out_of_ssa_tag : 1;
 197
 198   /* Used when building root_var structures in tree_ssa_live.[ch].  */
 199   unsigned root_var_processed : 1;
 200
 201   /* If nonzero, this variable is a memory tag.  */
 202   ENUM_BITFIELD (mem_tag_kind) mem_tag_kind : 2;
 203
 204   /* Nonzero if this variable is an alias tag that represents references to
 205      other variables (i.e., this variable appears in the MAY_ALIASES array
 206      of other variables).  */
 207   unsigned is_alias_tag : 1;
 208
 209   /* Nonzero if this variable was used after SSA optimizations were
 210      applied.  We set this when translating out of SSA form.  */
 211   unsigned used : 1;
 212
 213   /* This field indicates whether or not the variable may need PHI nodes.
 214      See the enum's definition for more detailed information about the
 215      states.  */
 216   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 217
 218   /* Used during operand processing to determine if this variable is already
 219      in the vuse list.  */
 220   unsigned in_vuse_list : 1;
 221
 222   /* Used during operand processing to determine if this variable is already
 223      in the v_may_def list.  */
 224   unsigned in_v_may_def_list : 1;
 225
 226   /* An artificial variable representing the memory location pointed-to by
 227      all the pointers that TBAA (type-based alias analysis) considers
 228      to be aliased.  If the variable is not a pointer or if it is never
 229      dereferenced, this must be NULL.  */
 230   tree type_mem_tag;
 231
 232   /* Variables that may alias this variable.  */
 233   varray_type may_aliases;
 234
 235   /* Unique ID of this variable.  */
 236   size_t uid;
 237
 238   /* Used when going out of SSA form to indicate which partition this
 239      variable represents storage for.  */
 240   unsigned partition;
 241
 242   /* Used by the root-var object in tree-ssa-live.[ch].  */
 243   unsigned root_index;
 244
 245   /* Default definition for this symbol.  If this field is not NULL, it
 246      means that the first reference to this variable in the function is a
 247      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
 248      for this variable with an empty defining statement.  */
 249   tree default_def;
 250
 251   /* During into-ssa and the dominator optimizer, this field holds the
 252      current version of this variable (an SSA_NAME).  */
 253   tree current_def;
 254
 255   /* If this variable is a structure, this fields holds a list of
 256      symbols representing each of the fields of the structure.  */
 257   subvar_t subvars;
 258 };
 259
 260
 261 typedef struct immediate_use_iterator_d
 262 {
 263   ssa_use_operand_t *imm_use;
 264   ssa_use_operand_t *end_p;
 265   ssa_use_operand_t iter_node;
 266 } imm_use_iterator;
 267
 268
 269 /* Use this iterator when simply looking at stmts.  Adding, deleting or
 270    modifying stmts will cause this iterator to malfunction.  */
 271
 272 #define FOR_EACH_IMM_USE_FAST(DEST, ITER, SSAVAR)                       \
 273   for ((DEST) = first_readonly_imm_use (&(ITER), (SSAVAR));     \
 274        !end_readonly_imm_use_p (&(ITER));                       \
 275        (DEST) = next_readonly_imm_use (&(ITER)))
 276
 277
 278 #define FOR_EACH_IMM_USE_SAFE(DEST, ITER, SSAVAR)               \
 279   for ((DEST) = first_safe_imm_use (&(ITER), (SSAVAR));         \
 280        !end_safe_imm_use_p (&(ITER));                           \
 281        (DEST) = next_safe_imm_use (&(ITER)))
 282
 283 #define BREAK_FROM_SAFE_IMM_USE(ITER)                           \
 284    {                                                            \
 285      end_safe_imm_use_traverse (&(ITER));                       \
 286      break;                                                     \
 287    }
 288
 289 struct stmt_ann_d GTY(())
 290 {
 291   struct tree_ann_common_d common;
 292
 293   /* Nonzero if the statement has been modified (meaning that the operands
 294      need to be scanned again).  */
 295   unsigned modified : 1;
 296
 297   /* Nonzero if the statement makes aliased loads.  */
 298   unsigned makes_aliased_loads : 1;
 299
 300   /* Nonzero if the statement makes aliased stores.  */
 301   unsigned makes_aliased_stores : 1;
 302
 303   /* Nonzero if the statement makes references to volatile storage.  */
 304   unsigned has_volatile_ops : 1;
 305
 306   /* Nonzero if the statement makes a function call that may clobber global
 307      and local addressable variables.  */
 308   unsigned makes_clobbering_call : 1;
 309
 310   /* Basic block that contains this statement.  */
 311   basic_block bb;
 312
 313   /* Operand cache for stmt.  */
 314   struct stmt_operands_d GTY ((skip (""))) operands;
 315
 316   /* Set of variables that have had their address taken in the statement.  */
 317   bitmap addresses_taken;
 318
 319   /* Unique identifier for this statement.  These ID's are to be created
 320      by each pass on an as-needed basis in any order convenient for the
 321      pass which needs statement UIDs.  */
 322   unsigned int uid;
 323
 324  /* Auxiliary info specific to a pass.  At all times, this
 325     should either point to valid data or be NULL.  */
 326   PTR GTY ((skip (""))) aux;
 327
 328   /* Linked list of histograms for value-based profiling.  This is really a
 329      struct histogram_value*.  We use void* to avoid having to export that
 330      everywhere, and to avoid having to put it in GC memory.  */
 331
 332   void * GTY ((skip (""))) histograms;
 333 };
 334
 335 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 336 {
 337   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 338   struct var_ann_d GTY((tag ("VAR_ANN"))) decl;
 339   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 340 };
 341
 342 extern GTY(()) VEC(tree,gc) *modified_noreturn_calls;
 343
 344 typedef union tree_ann_d *tree_ann_t;
 345 typedef struct var_ann_d *var_ann_t;
 346 typedef struct stmt_ann_d *stmt_ann_t;
 347
 348 static inline tree_ann_t tree_ann (tree);
 349 static inline tree_ann_t get_tree_ann (tree);
 350 static inline var_ann_t var_ann (tree);
 351 static inline var_ann_t get_var_ann (tree);
 352 static inline stmt_ann_t stmt_ann (tree);
 353 static inline stmt_ann_t get_stmt_ann (tree);
 354 static inline enum tree_ann_type ann_type (tree_ann_t);
 355 static inline basic_block bb_for_stmt (tree);
 356 extern void set_bb_for_stmt (tree, basic_block);
 357 static inline bool noreturn_call_p (tree);
 358 static inline void update_stmt (tree);
 359 static inline bool stmt_modified_p (tree);
 360 static inline varray_type may_aliases (tree);
 361 static inline int get_lineno (tree);
 362 static inline const char *get_filename (tree);
 363 static inline bool is_exec_stmt (tree);
 364 static inline bool is_label_stmt (tree);
 365 static inline bitmap addresses_taken (tree);
 366 static inline void set_default_def (tree, tree);
 367 static inline tree default_def (tree);
 368
 369 /*---------------------------------------------------------------------------
 370                   Structure representing predictions in tree level.
 371 ---------------------------------------------------------------------------*/
 372 struct edge_prediction GTY((chain_next ("%h.next")))
 373 {
 374   struct edge_prediction *next;
 375   edge edge;
 376   enum br_predictor predictor;
 377   int probability;
 378 };
 379
 380 /* Accessors for basic block annotations.  */
 381 static inline tree phi_nodes (basic_block);
 382 static inline void set_phi_nodes (basic_block, tree);
 383
 384 /*---------------------------------------------------------------------------
 385                               Global declarations
 386 ---------------------------------------------------------------------------*/
 387 /* Array of all variables referenced in the function.  */
 388 extern GTY(()) VEC(tree,gc) *referenced_vars;
 389
 390 #define num_referenced_vars VEC_length (tree, referenced_vars)
 391 #define referenced_var(i) VEC_index (tree, referenced_vars, i)
 392
 393 /* Array of all SSA_NAMEs used in the function.  */
 394 extern GTY(()) VEC(tree,gc) *ssa_names;
 395
 396 #define num_ssa_names (VEC_length (tree, ssa_names))
 397 #define ssa_name(i) (VEC_index (tree, ssa_names, (i)))
 398
 399 /* Artificial variable used to model the effects of function calls.  */
 400 extern GTY(()) tree global_var;
 401
 402 /* Call clobbered variables in the function.  If bit I is set, then
 403    REFERENCED_VARS (I) is call-clobbered.  */
 404 extern bitmap call_clobbered_vars;
 405
 406 /* Addressable variables in the function.  If bit I is set, then
 407    REFERENCED_VARS (I) has had its address taken.  */
 408 extern bitmap addressable_vars;
 409
 410 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 411 extern bool aliases_computed_p;
 412
 413 /* Macros for showing usage statistics.  */
 414 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 415                   ? (x)                                 \
 416                   : ((x) < 1024*1024*10                 \
 417                      ? (x) / 1024                       \
 418                      : (x) / (1024*1024))))
 419
 420 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 421
 422 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 423
 424 /*---------------------------------------------------------------------------
 425                               Block iterators
 426 ---------------------------------------------------------------------------*/
 427
 428 typedef struct {
 429   tree_stmt_iterator tsi;
 430   basic_block bb;
 431 } block_stmt_iterator;
 432
 433 static inline block_stmt_iterator bsi_start (basic_block);
 434 static inline block_stmt_iterator bsi_last (basic_block);
 435 static inline block_stmt_iterator bsi_after_labels (basic_block);
 436 block_stmt_iterator bsi_for_stmt (tree);
 437 static inline bool bsi_end_p (block_stmt_iterator);
 438 static inline void bsi_next (block_stmt_iterator *);
 439 static inline void bsi_prev (block_stmt_iterator *);
 440 static inline tree bsi_stmt (block_stmt_iterator);
 441 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 442
 443 extern void bsi_remove (block_stmt_iterator *);
 444 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 445 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 446 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 447
 448 enum bsi_iterator_update
 449 {
 450   /* Note that these are intentionally in the same order as TSI_FOO.  They
 451      mean exactly the same as their TSI_* counterparts.  */
 452   BSI_NEW_STMT,
 453   BSI_SAME_STMT,
 454   BSI_CHAIN_START,
 455   BSI_CHAIN_END,
 456   BSI_CONTINUE_LINKING
 457 };
 458
 459 extern void bsi_insert_before (block_stmt_iterator *, tree,
 460                                enum bsi_iterator_update);
 461 extern void bsi_insert_after (block_stmt_iterator *, tree,
 462                               enum bsi_iterator_update);
 463
 464 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 465
 466 /*---------------------------------------------------------------------------
 467                               Function prototypes
 468 ---------------------------------------------------------------------------*/
 469 /* In tree-cfg.c  */
 470
 471 /* Location to track pending stmt for edge insertion.  */
 472 #define PENDING_STMT(e) ((e)->insns.t)
 473
 474 extern void delete_tree_cfg_annotations (void);
 475 extern void disband_implicit_edges (void);
 476 extern bool stmt_ends_bb_p (tree);
 477 extern bool is_ctrl_stmt (tree);
 478 extern bool is_ctrl_altering_stmt (tree);
 479 extern bool computed_goto_p (tree);
 480 extern bool simple_goto_p (tree);
 481 extern void tree_dump_bb (basic_block, FILE *, int);
 482 extern void debug_tree_bb (basic_block);
 483 extern basic_block debug_tree_bb_n (int);
 484 extern void dump_tree_cfg (FILE *, int);
 485 extern void debug_tree_cfg (int);
 486 extern void dump_cfg_stats (FILE *);
 487 extern void debug_cfg_stats (void);
 488 extern void debug_loop_ir (void);
 489 extern void print_loop_ir (FILE *);
 490 extern void cleanup_dead_labels (void);
 491 extern void group_case_labels (void);
 492 extern bool cleanup_tree_cfg (void);
 493 extern void cleanup_tree_cfg_loop (void);
 494 extern tree first_stmt (basic_block);
 495 extern tree last_stmt (basic_block);
 496 extern tree *last_stmt_ptr (basic_block);
 497 extern tree last_and_only_stmt (basic_block);
 498 extern edge find_taken_edge (basic_block, tree);
 499 extern basic_block label_to_block_fn (struct function *, tree);
 500 #define label_to_block(t) (label_to_block_fn (cfun, t))
 501 extern void bsi_insert_on_edge (edge, tree);
 502 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 503 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 504 extern void bsi_commit_edge_inserts (void);
 505 extern void notice_special_calls (tree);
 506 extern void clear_special_calls (void);
 507 extern void verify_stmts (void);
 508 extern tree tree_block_label (basic_block);
 509 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 510 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 511                                         basic_block *);
 512 extern void add_phi_args_after_copy_bb (basic_block);
 513 extern void add_phi_args_after_copy (basic_block *, unsigned);
 514 extern bool tree_purge_dead_eh_edges (basic_block);
 515 extern bool tree_purge_all_dead_eh_edges (bitmap);
 516 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 517 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 518                              tree, tree);
 519 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 520                              tree, tree, tree);
 521 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 522                              tree, tree, tree, tree);
 523 extern void init_empty_tree_cfg (void);
 524 extern void fold_cond_expr_cond (void);
 525 extern void replace_uses_by (tree, tree);
 526
 527 /* In tree-pretty-print.c.  */
 528 extern void dump_generic_bb (FILE *, basic_block, int, int);
 529
 530 /* In tree-dfa.c  */
 531 extern var_ann_t create_var_ann (tree);
 532 extern stmt_ann_t create_stmt_ann (tree);
 533 extern tree_ann_t create_tree_ann (tree);
 534 extern void reserve_phi_args_for_new_edge (basic_block);
 535 extern tree create_phi_node (tree, basic_block);
 536 extern void add_phi_arg (tree, tree, edge);
 537 extern void remove_phi_args (edge);
 538 extern void remove_phi_node (tree, tree);
 539 extern tree phi_reverse (tree);
 540 extern void dump_dfa_stats (FILE *);
 541 extern void debug_dfa_stats (void);
 542 extern void debug_referenced_vars (void);
 543 extern void dump_referenced_vars (FILE *);
 544 extern void dump_variable (FILE *, tree);
 545 extern void debug_variable (tree);
 546 extern tree get_virtual_var (tree);
 547 extern void add_referenced_tmp_var (tree);
 548 extern void mark_new_vars_to_rename (tree);
 549 extern void find_new_referenced_vars (tree *);
 550
 551 extern tree make_rename_temp (tree, const char *);
 552
 553 /* In gimple-low.c  */
 554 extern void record_vars (tree);
 555 extern bool block_may_fallthru (tree block);
 556
 557 /* In tree-ssa-alias.c  */
 558 extern void dump_may_aliases_for (FILE *, tree);
 559 extern void debug_may_aliases_for (tree);
 560 extern void dump_alias_info (FILE *);
 561 extern void debug_alias_info (void);
 562 extern void dump_points_to_info (FILE *);
 563 extern void debug_points_to_info (void);
 564 extern void dump_points_to_info_for (FILE *, tree);
 565 extern void debug_points_to_info_for (tree);
 566 extern bool may_be_aliased (tree);
 567 extern struct ptr_info_def *get_ptr_info (tree);
 568 extern void add_type_alias (tree, tree);
 569 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 570 static inline subvar_t get_subvars_for_var (tree);
 571 static inline bool ref_contains_array_ref (tree);
 572 extern tree okay_component_ref_for_subvars (tree, HOST_WIDE_INT *,
 573                                             HOST_WIDE_INT *);
 574 static inline bool var_can_have_subvars (tree);
 575 static inline bool overlap_subvar (HOST_WIDE_INT, HOST_WIDE_INT,
 576                                    subvar_t, bool *);
 577
 578 /* Call-back function for walk_use_def_chains().  At each reaching
 579    definition, a function with this prototype is called.  */
 580 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 581
 582
 583 /* In tree-ssa.c  */
 584 extern void init_tree_ssa (void);
 585 extern edge ssa_redirect_edge (edge, basic_block);
 586 extern void flush_pending_stmts (edge);
 587 extern bool tree_ssa_useless_type_conversion (tree);
 588 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 589 extern void verify_ssa (bool);
 590 extern void delete_tree_ssa (void);
 591 extern void register_new_def (tree, VEC(tree,heap) **);
 592 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 593 extern bool stmt_references_memory_p (tree);
 594
 595 /* In tree-into-ssa.c  */
 596 void update_ssa (unsigned);
 597 void delete_update_ssa (void);
 598 void register_new_name_mapping (tree, tree);
 599 tree create_new_def_for (tree, tree, def_operand_p);
 600 bool need_ssa_update_p (void);
 601 bool name_registered_for_update_p (tree);
 602 bitmap ssa_names_to_replace (void);
 603 void release_ssa_name_after_update_ssa (tree name);
 604 void compute_global_livein (bitmap, bitmap);
 605 tree duplicate_ssa_name (tree, tree);
 606 void mark_sym_for_renaming (tree);
 607 void mark_set_for_renaming (bitmap);
 608 tree get_current_def (tree);
 609 void set_current_def (tree, tree);
 610
 611 /* In tree-ssa-ccp.c  */
 612 bool fold_stmt (tree *);
 613 bool fold_stmt_inplace (tree);
 614 tree widen_bitfield (tree, tree, tree);
 615
 616 /* In tree-vrp.c  */
 617 value_range *get_value_range (tree);
 618 void dump_value_range (FILE *, value_range *);
 619 void debug_value_range (value_range *);
 620 void dump_all_value_ranges (FILE *);
 621 void debug_all_value_ranges (void);
 622 bool expr_computes_nonzero (tree);
 623
 624 /* In tree-ssa-dom.c  */
 625 extern void dump_dominator_optimization_stats (FILE *);
 626 extern void debug_dominator_optimization_stats (void);
 627 int loop_depth_of_name (tree);
 628
 629 /* In tree-ssa-copy.c  */
 630 extern void propagate_value (use_operand_p, tree);
 631 extern void propagate_tree_value (tree *, tree);
 632 extern void replace_exp (use_operand_p, tree);
 633 extern bool may_propagate_copy (tree, tree);
 634 extern bool may_propagate_copy_into_asm (tree);
 635
 636 /* Description of number of iterations of a loop.  All the expressions inside
 637    the structure can be evaluated at the end of the loop's preheader
 638    (and due to ssa form, also anywhere inside the body of the loop).  */
 639
 640 struct tree_niter_desc
 641 {
 642   tree assumptions;     /* The boolean expression.  If this expression evaluates
 643                            to false, then the other fields in this structure
 644                            should not be used; there is no guarantee that they
 645                            will be correct.  */
 646   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 647                            the loop will exit in the first iteration (i.e.
 648                            its latch will not be executed), even if the niter
 649                            field says otherwise.  */
 650   tree niter;           /* The expression giving the number of iterations of
 651                            a loop (provided that assumptions == true and
 652                            may_be_zero == false), more precisely the number
 653                            of executions of the latch of the loop.  */
 654   tree additional_info; /* The boolean expression.  Sometimes we use additional
 655                            knowledge to simplify the other expressions
 656                            contained in this structure (for example the
 657                            knowledge about value ranges of operands on entry to
 658                            the loop).  If this is a case, conjunction of such
 659                            condition is stored in this field, so that we do not
 660                            lose the information: for example if may_be_zero
 661                            is (n <= 0) and niter is (unsigned) n, we know
 662                            that the number of iterations is at most
 663                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 664                            is eliminated (by looking at the guard on entry of
 665                            the loop), then the information would be lost.  */
 666 };
 667
 668 /* In tree-vectorizer.c */
 669 void vectorize_loops (struct loops *);
 670
 671 /* In tree-ssa-phiopt.c */
 672 bool empty_block_p (basic_block);
 673
 674 /* In tree-ssa-loop*.c  */
 675
 676 void tree_ssa_lim (struct loops *);
 677 void tree_ssa_unswitch_loops (struct loops *);
 678 void canonicalize_induction_variables (struct loops *);
 679 void tree_unroll_loops_completely (struct loops *, bool);
 680 void tree_ssa_iv_optimize (struct loops *);
 681
 682 bool number_of_iterations_exit (struct loop *, edge,
 683                                 struct tree_niter_desc *niter);
 684 tree find_loop_niter (struct loop *, edge *);
 685 tree loop_niter_by_eval (struct loop *, edge);
 686 tree find_loop_niter_by_eval (struct loop *, edge *);
 687 void estimate_numbers_of_iterations (struct loops *);
 688 tree can_count_iv_in_wider_type (struct loop *, tree, tree, tree, tree);
 689 void free_numbers_of_iterations_estimates (struct loops *);
 690 void rewrite_into_loop_closed_ssa (bitmap, unsigned);
 691 void verify_loop_closed_ssa (void);
 692 void loop_commit_inserts (void);
 693 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 694 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 695                 tree *, tree *);
 696 void split_loop_exit_edge (edge);
 697 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
 698 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 699                                      bool *);
 700 basic_block ip_end_pos (struct loop *);
 701 basic_block ip_normal_pos (struct loop *);
 702 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
 703                                          unsigned int, sbitmap,
 704                                          edge, edge *,
 705                                          unsigned int *, int);
 706 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
 707                                     basic_block *);
 708 tree expand_simple_operations (tree);
 709
 710 /* In tree-ssa-loop-im.c  */
 711 /* The possibilities of statement movement.  */
 712
 713 enum move_pos
 714   {
 715     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 716     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 717                                    become executed -- memory accesses, ... */
 718     MOVE_POSSIBLE               /* Unlimited movement.  */
 719   };
 720 extern enum move_pos movement_possibility (tree);
 721
 722 /* In tree-flow-inline.h  */
 723 static inline bool is_call_clobbered (tree);
 724 static inline void mark_call_clobbered (tree);
 725 static inline void set_is_used (tree);
 726 static inline bool unmodifiable_var_p (tree);
 727
 728 /* In tree-eh.c  */
 729 extern void make_eh_edges (tree);
 730 extern bool tree_could_trap_p (tree);
 731 extern bool tree_could_throw_p (tree);
 732 extern bool tree_can_throw_internal (tree);
 733 extern bool tree_can_throw_external (tree);
 734 extern int lookup_stmt_eh_region (tree);
 735 extern void add_stmt_to_eh_region (tree, int);
 736 extern bool remove_stmt_from_eh_region (tree);
 737 extern bool maybe_clean_or_replace_eh_stmt (tree, tree);
 738
 739 /* In tree-ssa-pre.c  */
 740 void add_to_value (tree, tree);
 741 void debug_value_expressions (tree);
 742 void print_value_expressions (FILE *, tree);
 743
 744
 745 /* In tree-vn.c  */
 746 bool expressions_equal_p (tree, tree);
 747 tree get_value_handle (tree);
 748 hashval_t vn_compute (tree, hashval_t, tree);
 749 tree vn_lookup_or_add (tree, tree);
 750 void vn_add (tree, tree, tree);
 751 tree vn_lookup (tree, tree);
 752 void vn_init (void);
 753 void vn_delete (void);
 754
 755 /* In tree-ssa-sink.c  */
 756 bool is_hidden_global_store (tree);
 757
 758 /* In tree-sra.c  */
 759 void insert_edge_copies (tree, basic_block);
 760
 761 /* In tree-loop-linear.c  */
 762 extern void linear_transform_loops (struct loops *);
 763
 764 /* In tree-ssa-loop-ivopts.c  */
 765 extern bool expr_invariant_in_loop_p (struct loop *, tree);
 766
 767 /* In tree-ssa-threadupdate.c.  */
 768 extern bool thread_through_all_blocks (bitmap);
 769
 770 /* In gimplify.c  */
 771 tree force_gimple_operand (tree, tree *, bool, tree);
 772 tree force_gimple_operand_bsi (block_stmt_iterator *, tree, bool, tree);
 773
 774 #include "tree-flow-inline.h"
 775
 776 #endif /* _TREE_FLOW_H  */