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
 144 struct var_ann_d GTY(())
 145 {
 146   struct tree_ann_common_d common;
 147
 148   /* Used by the out of SSA pass to determine whether this variable has
 149      been seen yet or not.  */
 150   unsigned out_of_ssa_tag : 1;
 151
 152   /* Used when building root_var structures in tree_ssa_live.[ch].  */
 153   unsigned root_var_processed : 1;
 154
 155   /* If nonzero, this variable is a memory tag.  */
 156   ENUM_BITFIELD (mem_tag_kind) mem_tag_kind : 2;
 157
 158   /* Nonzero if this variable is an alias tag that represents references to
 159      other variables (i.e., this variable appears in the MAY_ALIASES array
 160      of other variables).  */
 161   unsigned is_alias_tag : 1;
 162
 163   /* Nonzero if this variable was used after SSA optimizations were
 164      applied.  We set this when translating out of SSA form.  */
 165   unsigned used : 1;
 166
 167   /* This field indicates whether or not the variable may need PHI nodes.
 168      See the enum's definition for more detailed information about the
 169      states.  */
 170   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 171
 172   /* Used during operand processing to determine if this variable is already
 173      in the vuse list.  */
 174   unsigned in_vuse_list : 1;
 175
 176   /* Used during operand processing to determine if this variable is already
 177      in the v_may_def list.  */
 178   unsigned in_v_may_def_list : 1;
 179
 180   /* An artificial variable representing the memory location pointed-to by
 181      all the pointers that TBAA (type-based alias analysis) considers
 182      to be aliased.  If the variable is not a pointer or if it is never
 183      dereferenced, this must be NULL.  */
 184   tree type_mem_tag;
 185
 186   /* Variables that may alias this variable.  */
 187   varray_type may_aliases;
 188
 189   /* Unique ID of this variable.  */
 190   size_t uid;
 191
 192   /* Used when going out of SSA form to indicate which partition this
 193      variable represents storage for.  */
 194   unsigned partition;
 195
 196   /* Used by the root-var object in tree-ssa-live.[ch].  */
 197   unsigned root_index;
 198
 199   /* Default definition for this symbol.  If this field is not NULL, it
 200      means that the first reference to this variable in the function is a
 201      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
 202      for this variable with an empty defining statement.  */
 203   tree default_def;
 204
 205   /* During into-ssa and the dominator optimizer, this field holds the
 206      current version of this variable (an SSA_NAME).
 207
 208      This was previously two varrays (one in into-ssa the other in the
 209      dominator optimizer).  That is wasteful, particularly since the
 210      dominator optimizer calls into-ssa resulting in having two varrays
 211      live at the same time and this can happen for each call to the
 212      dominator optimizer.  */
 213   tree current_def;
 214 };
 215
 216
 217 struct dataflow_d GTY(())
 218 {
 219   /* Immediate uses.  This is a list of all the statements and PHI nodes
 220      that are immediately reached by the definitions made in this
 221      statement.  */
 222   varray_type immediate_uses;
 223
 224   /* Use this array for very small numbers of uses instead of the varray.  */
 225   tree uses[2];
 226
 227   /* Reached uses.  This is a list of all the possible program statements
 228      that may be reached directly or indirectly by definitions made in this
 229      statement.  Notice that this is a superset of IMMEDIATE_USES.
 230      For instance, given the following piece of code:
 231
 232             1   a1 = 10;
 233             2   if (a1 > 3)
 234             3     a2 = a1 + 5;
 235             4   a3 = PHI (a1, a2)
 236             5   b1 = a3 - 2;
 237
 238      IMMEDIATE_USES for statement #1 are all those statements that use a1
 239      directly (i.e., #2, #3 and #4).  REACHED_USES for statement #1 also
 240      includes statement #5 because 'a1' could reach 'a3' via the PHI node
 241      at statement #4.  The set of REACHED_USES is then the transitive
 242      closure over all the PHI nodes in the IMMEDIATE_USES set.  */
 243
 244   /* Reaching definitions.  Similarly to REACHED_USES, the set
 245      REACHING_DEFS is the set of all the statements that make definitions
 246      that may reach this statement.  Notice that we don't need to have a
 247      similar entry for immediate definitions, as these are represented by
 248      the SSA_NAME nodes themselves (each SSA_NAME node contains a pointer
 249      to the statement that makes that definition).  */
 250 };
 251
 252 typedef struct dataflow_d *dataflow_t;
 253
 254
 255 struct stmt_ann_d GTY(())
 256 {
 257   struct tree_ann_common_d common;
 258
 259   /* Nonzero if the statement has been modified (meaning that the operands
 260      need to be scanned again).  */
 261   unsigned modified : 1;
 262
 263   /* Nonzero if the statement makes aliased loads.  */
 264   unsigned makes_aliased_loads : 1;
 265
 266   /* Nonzero if the statement makes aliased stores.  */
 267   unsigned makes_aliased_stores : 1;
 268
 269   /* Nonzero if the statement makes references to volatile storage.  */
 270   unsigned has_volatile_ops : 1;
 271
 272   /* Nonzero if the statement makes a function call that may clobber global
 273      and local addressable variables.  */
 274   unsigned makes_clobbering_call : 1;
 275
 276   /* Basic block that contains this statement.  */
 277   basic_block GTY ((skip (""))) bb;
 278
 279   struct stmt_operands_d operands;
 280
 281   /* Dataflow information.  */
 282   dataflow_t df;
 283
 284   /* Set of variables that have had their address taken in the statement.  */
 285   bitmap addresses_taken;
 286
 287   /* Unique identifier for this statement.  These ID's are to be created
 288      by each pass on an as-needed basis in any order convenient for the
 289      pass which needs statement UIDs.  */
 290   unsigned int uid;
 291 };
 292
 293 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 294 {
 295   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 296   struct var_ann_d GTY((tag ("VAR_ANN"))) decl;
 297   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 298 };
 299
 300 extern GTY(()) VEC(tree) *modified_noreturn_calls;
 301
 302 typedef union tree_ann_d *tree_ann_t;
 303 typedef struct var_ann_d *var_ann_t;
 304 typedef struct stmt_ann_d *stmt_ann_t;
 305
 306 static inline tree_ann_t tree_ann (tree);
 307 static inline tree_ann_t get_tree_ann (tree);
 308 static inline var_ann_t var_ann (tree);
 309 static inline var_ann_t get_var_ann (tree);
 310 static inline stmt_ann_t stmt_ann (tree);
 311 static inline stmt_ann_t get_stmt_ann (tree);
 312 static inline enum tree_ann_type ann_type (tree_ann_t);
 313 static inline basic_block bb_for_stmt (tree);
 314 extern void set_bb_for_stmt (tree, basic_block);
 315 static inline bool noreturn_call_p (tree);
 316 static inline void modify_stmt (tree);
 317 static inline void unmodify_stmt (tree);
 318 static inline bool stmt_modified_p (tree);
 319 static inline varray_type 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 v_may_def_optype get_v_may_def_ops (stmt_ann_t);
 325 static inline vuse_optype get_vuse_ops (stmt_ann_t);
 326 static inline use_optype get_use_ops (stmt_ann_t);
 327 static inline def_optype get_def_ops (stmt_ann_t);
 328 static inline bitmap addresses_taken (tree);
 329 static inline int num_immediate_uses (dataflow_t);
 330 static inline tree immediate_use (dataflow_t, int);
 331 static inline dataflow_t get_immediate_uses (tree);
 332 static inline void set_default_def (tree, tree);
 333 static inline tree default_def (tree);
 334
 335 /*---------------------------------------------------------------------------
 336                   Structure representing predictions in tree level.
 337 ---------------------------------------------------------------------------*/
 338 struct edge_prediction GTY((chain_next ("%h.next")))
 339 {
 340   struct edge_prediction *next;
 341   edge edge;
 342   enum br_predictor predictor;
 343   int probability;
 344 };
 345
 346 /*---------------------------------------------------------------------------
 347                   Block annotations stored in basic_block.tree_annotations
 348 ---------------------------------------------------------------------------*/
 349 struct bb_ann_d GTY(())
 350 {
 351   /* Chain of PHI nodes for this block.  */
 352   tree phi_nodes;
 353
 354   /* Nonzero if this block contains an escape point (see is_escape_site).  */
 355   unsigned has_escape_site : 1;
 356
 357   /* Nonzero if one or more incoming edges to this block should be threaded
 358      to an outgoing edge of this block.  */
 359   unsigned incoming_edge_threaded : 1;
 360
 361   struct edge_prediction *predictions;
 362 };
 363
 364 typedef struct bb_ann_d *bb_ann_t;
 365
 366 /* Accessors for basic block annotations.  */
 367 static inline bb_ann_t bb_ann (basic_block);
 368 static inline tree phi_nodes (basic_block);
 369 static inline void set_phi_nodes (basic_block, tree);
 370
 371 /*---------------------------------------------------------------------------
 372                               Global declarations
 373 ---------------------------------------------------------------------------*/
 374 /* Array of all variables referenced in the function.  */
 375 extern GTY(()) varray_type referenced_vars;
 376
 377 #define num_referenced_vars VARRAY_ACTIVE_SIZE (referenced_vars)
 378 #define referenced_var(i) VARRAY_TREE (referenced_vars, i)
 379
 380 /* Array of all SSA_NAMEs used in the function.  */
 381 extern GTY(()) varray_type ssa_names;
 382
 383 #define num_ssa_names VARRAY_ACTIVE_SIZE (ssa_names)
 384 #define ssa_name(i) VARRAY_TREE (ssa_names, i)
 385
 386 /* Artificial variable used to model the effects of function calls.  */
 387 extern GTY(()) tree global_var;
 388
 389 /* Call clobbered variables in the function.  If bit I is set, then
 390    REFERENCED_VARS (I) is call-clobbered.  */
 391 extern bitmap call_clobbered_vars;
 392
 393 /* Addressable variables in the function.  If bit I is set, then
 394    REFERENCED_VARS (I) has had its address taken.  */
 395 extern bitmap addressable_vars;
 396
 397 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 398 extern bool aliases_computed_p;
 399
 400 /* Macros for showing usage statistics.  */
 401 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 402                   ? (x)                                 \
 403                   : ((x) < 1024*1024*10                 \
 404                      ? (x) / 1024                       \
 405                      : (x) / (1024*1024))))
 406
 407 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 408
 409 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 410
 411
 412 /*---------------------------------------------------------------------------
 413                               Block iterators
 414 ---------------------------------------------------------------------------*/
 415
 416 typedef struct {
 417   tree_stmt_iterator tsi;
 418   basic_block bb;
 419 } block_stmt_iterator;
 420
 421 static inline block_stmt_iterator bsi_start (basic_block);
 422 static inline block_stmt_iterator bsi_last (basic_block);
 423 static inline block_stmt_iterator bsi_after_labels (basic_block);
 424 block_stmt_iterator bsi_for_stmt (tree);
 425 static inline bool bsi_end_p (block_stmt_iterator);
 426 static inline void bsi_next (block_stmt_iterator *);
 427 static inline void bsi_prev (block_stmt_iterator *);
 428 static inline tree bsi_stmt (block_stmt_iterator);
 429 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 430
 431 extern void bsi_remove (block_stmt_iterator *);
 432 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 433 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 434 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 435
 436 enum bsi_iterator_update
 437 {
 438   /* Note that these are intentionally in the same order as TSI_FOO.  They
 439      mean exactly the same as their TSI_* counterparts.  */
 440   BSI_NEW_STMT,
 441   BSI_SAME_STMT,
 442   BSI_CHAIN_START,
 443   BSI_CHAIN_END,
 444   BSI_CONTINUE_LINKING
 445 };
 446
 447 extern void bsi_insert_before (block_stmt_iterator *, tree,
 448                                enum bsi_iterator_update);
 449 extern void bsi_insert_after (block_stmt_iterator *, tree,
 450                               enum bsi_iterator_update);
 451
 452 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 453
 454 /*---------------------------------------------------------------------------
 455                               Function prototypes
 456 ---------------------------------------------------------------------------*/
 457 /* In tree-cfg.c  */
 458
 459 /* Location to track pending stmt for edge insertion.  */
 460 #define PENDING_STMT(e) ((e)->insns.t)
 461
 462 extern void delete_tree_cfg_annotations (void);
 463 extern void disband_implicit_edges (void);
 464 extern bool stmt_ends_bb_p (tree);
 465 extern bool is_ctrl_stmt (tree);
 466 extern bool is_ctrl_altering_stmt (tree);
 467 extern bool computed_goto_p (tree);
 468 extern bool simple_goto_p (tree);
 469 extern void tree_dump_bb (basic_block, FILE *, int);
 470 extern void debug_tree_bb (basic_block);
 471 extern basic_block debug_tree_bb_n (int);
 472 extern void dump_tree_cfg (FILE *, int);
 473 extern void debug_tree_cfg (int);
 474 extern void dump_cfg_stats (FILE *);
 475 extern void debug_cfg_stats (void);
 476 extern void debug_loop_ir (void);
 477 extern void print_loop_ir (FILE *);
 478 extern void cleanup_dead_labels (void);
 479 extern void group_case_labels (void);
 480 extern bool cleanup_tree_cfg (void);
 481 extern tree first_stmt (basic_block);
 482 extern tree last_stmt (basic_block);
 483 extern tree *last_stmt_ptr (basic_block);
 484 extern tree last_and_only_stmt (basic_block);
 485 extern edge find_taken_edge (basic_block, tree);
 486 extern void cfg_remove_useless_stmts (void);
 487 extern basic_block label_to_block (tree);
 488 extern void bsi_insert_on_edge (edge, tree);
 489 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 490 extern void bsi_commit_one_edge_insert (edge, basic_block *);
 491 extern void bsi_commit_edge_inserts (void);
 492 extern void notice_special_calls (tree);
 493 extern void clear_special_calls (void);
 494 extern void verify_stmts (void);
 495 extern tree tree_block_label (basic_block);
 496 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 497 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 498                                         basic_block *);
 499 extern void add_phi_args_after_copy_bb (basic_block);
 500 extern void add_phi_args_after_copy (basic_block *, unsigned);
 501 extern void rewrite_to_new_ssa_names_bb (basic_block, struct htab *);
 502 extern void rewrite_to_new_ssa_names (basic_block *, unsigned, htab_t);
 503 extern void allocate_ssa_names (bitmap, struct htab **);
 504 extern bool tree_purge_dead_eh_edges (basic_block);
 505 extern bool tree_purge_all_dead_eh_edges (bitmap);
 506 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 507 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 508                              tree, tree);
 509 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 510                              tree, tree, tree);
 511 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 512                              tree, tree, tree, tree);
 513
 514 /* In tree-pretty-print.c.  */
 515 extern void dump_generic_bb (FILE *, basic_block, int, int);
 516
 517 /* In tree-dfa.c  */
 518 extern var_ann_t create_var_ann (tree);
 519 extern stmt_ann_t create_stmt_ann (tree);
 520 extern tree_ann_t create_tree_ann (tree);
 521 extern void reserve_phi_args_for_new_edge (basic_block);
 522 extern tree create_phi_node (tree, basic_block);
 523 extern void add_phi_arg (tree, tree, edge);
 524 extern void remove_phi_args (edge);
 525 extern void remove_phi_node (tree, tree, basic_block);
 526 extern void remove_all_phi_nodes_for (bitmap);
 527 extern tree phi_reverse (tree);
 528 extern void dump_dfa_stats (FILE *);
 529 extern void debug_dfa_stats (void);
 530 extern void debug_referenced_vars (void);
 531 extern void dump_referenced_vars (FILE *);
 532 extern void dump_variable (FILE *, tree);
 533 extern void debug_variable (tree);
 534 extern void dump_immediate_uses (FILE *);
 535 extern void debug_immediate_uses (void);
 536 extern void dump_immediate_uses_for (FILE *, tree);
 537 extern void debug_immediate_uses_for (tree);
 538 extern void compute_immediate_uses (int, bool (*)(tree));
 539 extern void free_df (void);
 540 extern void free_df_for_stmt (tree);
 541 extern tree get_virtual_var (tree);
 542 extern void add_referenced_tmp_var (tree);
 543 extern void mark_new_vars_to_rename (tree, bitmap);
 544 extern void find_new_referenced_vars (tree *);
 545 void mark_call_clobbered_vars_to_rename (void);
 546
 547 extern void redirect_immediate_uses (tree, tree);
 548 extern tree make_rename_temp (tree, const char *);
 549
 550 /* Flags used when computing reaching definitions and reached uses.  */
 551 #define TDFA_USE_OPS            (1 << 0)
 552 #define TDFA_USE_VOPS           (1 << 1)
 553
 554 /* In gimple-low.c  */
 555 struct lower_data;
 556 extern void lower_stmt_body (tree, struct lower_data *);
 557 extern void record_vars (tree);
 558 extern bool block_may_fallthru (tree block);
 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
 572 /* Call-back function for walk_use_def_chains().  At each reaching
 573    definition, a function with this prototype is called.  */
 574 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 575
 576 typedef tree tree_on_heap;
 577 DEF_VEC_MALLOC_P (tree_on_heap);
 578
 579 /* In tree-ssa.c  */
 580 extern void init_tree_ssa (void);
 581 extern void dump_tree_ssa (FILE *);
 582 extern void debug_tree_ssa (void);
 583 extern void debug_def_blocks (void);
 584 extern void dump_tree_ssa_stats (FILE *);
 585 extern void debug_tree_ssa_stats (void);
 586 extern edge ssa_redirect_edge (edge, basic_block);
 587 extern void flush_pending_stmts (edge);
 588 extern bool tree_ssa_useless_type_conversion (tree);
 589 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 590 extern void verify_ssa (void);
 591 extern void delete_tree_ssa (void);
 592 extern void register_new_def (tree, VEC (tree_on_heap) **);
 593 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 594 extern void kill_redundant_phi_nodes (void);
 595 extern bool stmt_references_memory_p (tree);
 596
 597 /* In tree-into-ssa.c  */
 598 extern void rewrite_into_ssa (bool);
 599 extern void rewrite_ssa_into_ssa (void);
 600 extern void rewrite_def_def_chains (void);
 601
 602 void compute_global_livein (bitmap, bitmap);
 603 tree duplicate_ssa_name (tree, tree);
 604
 605 /* In tree-ssa-ccp.c  */
 606 bool fold_stmt (tree *);
 607 tree widen_bitfield (tree, tree, tree);
 608
 609 /* In tree-ssa-dom.c  */
 610 extern void dump_dominator_optimization_stats (FILE *);
 611 extern void debug_dominator_optimization_stats (void);
 612
 613 /* In tree-ssa-copy.c  */
 614 extern void propagate_value (use_operand_p, tree);
 615 extern void propagate_tree_value (tree *, tree);
 616 extern void replace_exp (use_operand_p, tree);
 617 extern bool may_propagate_copy (tree, tree);
 618 extern bool may_propagate_copy_into_asm (tree);
 619
 620 /* Description of number of iterations of a loop.  All the expressions inside
 621    the structure can be evaluated at the end of the loop's preheader
 622    (and due to ssa form, also anywhere inside the body of the loop).  */
 623
 624 struct tree_niter_desc
 625 {
 626   tree assumptions;     /* The boolean expression.  If this expression evaluates
 627                            to false, then the other fields in this structure
 628                            should not be used; there is no guarantee that they
 629                            will be correct.  */
 630   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 631                            the loop will exit in the first iteration (i.e.
 632                            its latch will not be executed), even if the niter
 633                            field says otherwise.  */
 634   tree niter;           /* The expression giving the number of iterations of
 635                            a loop (provided that assumptions == true and
 636                            may_be_zero == false), more precisely the number
 637                            of executions of the latch of the loop.  */
 638   tree additional_info; /* The boolean expression.  Sometimes we use additional
 639                            knowledge to simplify the other expressions
 640                            contained in this structure (for example the
 641                            knowledge about value ranges of operands on entry to
 642                            the loop).  If this is a case, conjunction of such
 643                            condition is stored in this field, so that we do not
 644                            lose the information: for example if may_be_zero
 645                            is (n <= 0) and niter is (unsigned) n, we know
 646                            that the number of iterations is at most
 647                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 648                            is eliminated (by looking at the guard on entry of
 649                            the loop), then the information would be lost.  */
 650 };
 651
 652 /* In tree-vectorizer.c */
 653 void vectorize_loops (struct loops *);
 654
 655 /* In tree-ssa-phiopt.c */
 656 bool empty_block_p (basic_block);
 657
 658 /* In tree-ssa-loop*.c  */
 659
 660 void tree_ssa_lim (struct loops *);
 661 void tree_ssa_unswitch_loops (struct loops *);
 662 void canonicalize_induction_variables (struct loops *);
 663 void tree_unroll_loops_completely (struct loops *);
 664 void tree_ssa_iv_optimize (struct loops *);
 665
 666 void number_of_iterations_cond (tree, tree, tree, enum tree_code, tree, tree,
 667                                 struct tree_niter_desc *);
 668 bool number_of_iterations_exit (struct loop *, edge,
 669                                 struct tree_niter_desc *niter);
 670 tree find_loop_niter (struct loop *, edge *);
 671 tree loop_niter_by_eval (struct loop *, edge);
 672 tree find_loop_niter_by_eval (struct loop *, edge *);
 673 void estimate_numbers_of_iterations (struct loops *);
 674 tree can_count_iv_in_wider_type (struct loop *, tree, tree, tree, tree);
 675 void free_numbers_of_iterations_estimates (struct loops *);
 676 void rewrite_into_loop_closed_ssa (void);
 677 void verify_loop_closed_ssa (void);
 678 void loop_commit_inserts (void);
 679 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 680 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 681                 tree *, tree *);
 682 void split_loop_exit_edge (edge);
 683 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
 684 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 685                                      bool *);
 686 basic_block ip_end_pos (struct loop *);
 687 basic_block ip_normal_pos (struct loop *);
 688 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
 689                                          unsigned int, sbitmap,
 690                                          edge, edge *,
 691                                          unsigned int *, int);
 692 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
 693                                     basic_block *);
 694
 695 /* In tree-ssa-loop-im.c  */
 696 /* The possibilities of statement movement.  */
 697
 698 enum move_pos
 699   {
 700     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 701     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 702                                    become executed -- memory accesses, ... */
 703     MOVE_POSSIBLE               /* Unlimited movement.  */
 704   };
 705 extern enum move_pos movement_possibility (tree);
 706
 707 /* In tree-flow-inline.h  */
 708 static inline bool is_call_clobbered (tree);
 709 static inline void mark_call_clobbered (tree);
 710 static inline void set_is_used (tree);
 711
 712 /* In tree-eh.c  */
 713 extern void make_eh_edges (tree);
 714 extern bool tree_could_trap_p (tree);
 715 extern bool tree_could_throw_p (tree);
 716 extern bool tree_can_throw_internal (tree);
 717 extern bool tree_can_throw_external (tree);
 718 extern int lookup_stmt_eh_region (tree);
 719 extern void add_stmt_to_eh_region (tree, int);
 720 extern bool remove_stmt_from_eh_region (tree);
 721 extern bool maybe_clean_eh_stmt (tree);
 722
 723 /* In tree-ssa-pre.c  */
 724 void add_to_value (tree, tree);
 725 void debug_value_expressions (tree);
 726 void print_value_expressions (FILE *, tree);
 727
 728
 729 /* In tree-vn.c  */
 730 bool expressions_equal_p (tree, tree);
 731 tree get_value_handle (tree);
 732 hashval_t vn_compute (tree, hashval_t, vuse_optype);
 733 tree vn_lookup_or_add (tree, vuse_optype);
 734 void vn_add (tree, tree, vuse_optype);
 735 tree vn_lookup (tree, vuse_optype);
 736 void vn_init (void);
 737 void vn_delete (void);
 738
 739
 740 /* In tree-sra.c  */
 741 void insert_edge_copies (tree, basic_block);
 742
 743 /* In tree-loop-linear.c  */
 744 extern void linear_transform_loops (struct loops *);
 745
 746 /* In tree-ssa-loop-ivopts.c  */
 747 extern bool expr_invariant_in_loop_p (struct loop *, tree);
 748 /* In gimplify.c  */
 749
 750 tree force_gimple_operand (tree, tree *, bool, tree);
 751
 752 #include "tree-flow-inline.h"
 753
 754 #endif /* _TREE_FLOW_H  */