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