gcc/tree-flow.h

   1 /* Data and Control Flow Analysis for Trees.
   2    Copyright (C) 2001, 2003, 2004 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   /* Set of variables that this pointer may point to.  */
  70   bitmap pt_vars;
  71
  72   /* If this pointer has been dereferenced, and points-to information is
  73      more precise than type-based aliasing, indirect references to this
  74      pointer will be represented by this memory tag, instead of the type
  75      tag computed by TBAA.  */
  76   tree name_mem_tag;
  77 };
  78
  79
  80 /*---------------------------------------------------------------------------
  81                    Tree annotations stored in tree_common.ann
  82 ---------------------------------------------------------------------------*/
  83 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, STMT_ANN };
  84
  85 struct tree_ann_common_d GTY(())
  86 {
  87   /* Annotation type.  */
  88   enum tree_ann_type type;
  89
  90  /* Auxiliary info specific to a pass.  At all times, this
  91     should either point to valid data or be NULL.  */
  92   PTR GTY ((skip (""))) aux;
  93
  94   /* The value handle for this expression.  Used by GVN-PRE.  */
  95   tree GTY((skip)) value_handle;
  96 };
  97
  98 /* It is advantageous to avoid things like life analysis for variables which
  99    do not need PHI nodes.  This enum describes whether or not a particular
 100    variable may need a PHI node.  */
 101
 102 enum need_phi_state {
 103   /* This is the default.  If we are still in this state after finding
 104      all the definition and use sites, then we will assume the variable
 105      needs PHI nodes.  This is probably an overly conservative assumption.  */
 106   NEED_PHI_STATE_UNKNOWN,
 107
 108   /* This state indicates that we have seen one or more sets of the
 109      variable in a single basic block and that the sets dominate all
 110      uses seen so far.  If after finding all definition and use sites
 111      we are still in this state, then the variable does not need any
 112      PHI nodes.  */
 113   NEED_PHI_STATE_NO,
 114
 115   /* This state indicates that we have either seen multiple definitions of
 116      the variable in multiple blocks, or that we encountered a use in a
 117      block that was not dominated by the block containing the set(s) of
 118      this variable.  This variable is assumed to need PHI nodes.  */
 119   NEED_PHI_STATE_MAYBE
 120 };
 121
 122
 123 /* When computing aliasing information, we represent the memory pointed-to
 124    by pointers with artificial variables called "memory tags" (MT).  There
 125    are two kinds of tags: type and name.  Type tags (TMT) are used in
 126    type-based alias analysis, they represent all the pointed-to locations
 127    and variables of the same alias set class.  Name tags (NMT) are used in
 128    flow-sensitive points-to alias analysis, they represent the variables
 129    and memory locations pointed-to by a specific SSA_NAME pointer.  */
 130 enum mem_tag_kind {
 131   /* This variable is not a memory tag.  */
 132   NOT_A_TAG,
 133
 134   /* This variable is a type memory tag (TMT).  */
 135   TYPE_TAG,
 136
 137   /* This variable is a name memory tag (NMT).  */
 138   NAME_TAG
 139 };
 140
 141 struct var_ann_d GTY(())
 142 {
 143   struct tree_ann_common_d common;
 144
 145   /* Used by the out of SSA pass to determine whether this variable has
 146      been seen yet or not.  */
 147   unsigned out_of_ssa_tag : 1;
 148
 149   /* Used when building root_var structures in tree_ssa_live.[ch].  */
 150   unsigned root_var_processed : 1;
 151
 152   /* If nonzero, this variable is a memory tag.  */
 153   ENUM_BITFIELD (mem_tag_kind) mem_tag_kind : 2;
 154
 155   /* Nonzero if this variable is an alias tag that represents references to
 156      other variables (i.e., this variable appears in the MAY_ALIASES array
 157      of other variables).  */
 158   unsigned is_alias_tag : 1;
 159
 160   /* Nonzero if this variable was used after SSA optimizations were
 161      applied.  We set this when translating out of SSA form.  */
 162   unsigned used : 1;
 163
 164   /* This field indicates whether or not the variable may need PHI nodes.
 165      See the enum's definition for more detailed information about the
 166      states.  */
 167   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 168
 169   /* An artificial variable representing the memory location pointed-to by
 170      all the pointers that TBAA (type-based alias analysis) considers
 171      to be aliased.  If the variable is not a pointer or if it is never
 172      dereferenced, this must be NULL.  */
 173   tree type_mem_tag;
 174
 175   /* Variables that may alias this variable.  */
 176   varray_type may_aliases;
 177
 178   /* Unique ID of this variable.  */
 179   size_t uid;
 180
 181   /* Used when going out of SSA form to indicate which partition this
 182      variable represents storage for.  */
 183   unsigned partition;
 184
 185   /* Used by the root-var object in tree-ssa-live.[ch].  */
 186   unsigned root_index;
 187
 188   /* Default definition for this symbol.  If this field is not NULL, it
 189      means that the first reference to this variable in the function is a
 190      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
 191      for this variable with an empty defining statement.  */
 192   tree default_def;
 193
 194   /* During into-ssa and the dominator optimizer, this field holds the
 195      current version of this variable (an SSA_NAME).
 196
 197      This was previously two varrays (one in into-ssa the other in the
 198      dominator optimizer).  That is wasteful, particularly since the
 199      dominator optimizer calls into-ssa resulting in having two varrays
 200      live at the same time and this can happen for each call to the
 201      dominator optimizer.  */
 202   tree current_def;
 203
 204   /* Pointer to the structure that contains the sets of global
 205      variables modified by function calls.  This field is only used
 206      for FUNCTION_DECLs.  */
 207   static_vars_info_t static_vars_info;
 208 };
 209
 210
 211 struct dataflow_d GTY(())
 212 {
 213   /* Immediate uses.  This is a list of all the statements and PHI nodes
 214      that are immediately reached by the definitions made in this
 215      statement.  */
 216   varray_type immediate_uses;
 217
 218   /* Use this array for very small numbers of uses instead of the varray.  */
 219   tree uses[2];
 220
 221   /* Reached uses.  This is a list of all the possible program statements
 222      that may be reached directly or indirectly by definitions made in this
 223      statement.  Notice that this is a superset of IMMEDIATE_USES.
 224      For instance, given the following piece of code:
 225
 226             1   a1 = 10;
 227             2   if (a1 > 3)
 228             3     a2 = a1 + 5;
 229             4   a3 = PHI (a1, a2)
 230             5   b1 = a3 - 2;
 231
 232      IMMEDIATE_USES for statement #1 are all those statements that use a1
 233      directly (i.e., #2, #3 and #4).  REACHED_USES for statement #1 also
 234      includes statement #5 because 'a1' could reach 'a3' via the PHI node
 235      at statement #4.  The set of REACHED_USES is then the transitive
 236      closure over all the PHI nodes in the IMMEDIATE_USES set.  */
 237
 238   /* Reaching definitions.  Similarly to REACHED_USES, the set
 239      REACHING_DEFS is the set of all the statements that make definitions
 240      that may reach this statement.  Notice that we don't need to have a
 241      similar entry for immediate definitions, as these are represented by
 242      the SSA_NAME nodes themselves (each SSA_NAME node contains a pointer
 243      to the statement that makes that definition).  */
 244 };
 245
 246 typedef struct dataflow_d *dataflow_t;
 247
 248
 249 struct stmt_ann_d GTY(())
 250 {
 251   struct tree_ann_common_d common;
 252
 253   /* Nonzero if the statement has been modified (meaning that the operands
 254      need to be scanned again).  */
 255   unsigned modified : 1;
 256
 257   /* Nonzero if the statement makes aliased loads.  */
 258   unsigned makes_aliased_loads : 1;
 259
 260   /* Nonzero if the statement makes aliased stores.  */
 261   unsigned makes_aliased_stores : 1;
 262
 263   /* Nonzero if the statement makes references to volatile storage.  */
 264   unsigned has_volatile_ops : 1;
 265
 266   /* Nonzero if the statement makes a function call that may clobber global
 267      and local addressable variables.  */
 268   unsigned makes_clobbering_call : 1;
 269
 270   /* Basic block that contains this statement.  */
 271   basic_block GTY ((skip (""))) bb;
 272
 273   struct stmt_operands_d operands;
 274
 275   /* Dataflow information.  */
 276   dataflow_t df;
 277
 278   /* Set of variables that have had their address taken in the statement.  */
 279   bitmap addresses_taken;
 280
 281   /* Unique identifier for this statement.  These ID's are to be created
 282      by each pass on an as-needed basis in any order convenient for the
 283      pass which needs statement UIDs.  */
 284   unsigned int uid;
 285 };
 286
 287 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 288 {
 289   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 290   struct var_ann_d GTY((tag ("VAR_ANN"))) decl;
 291   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 292 };
 293
 294 typedef union tree_ann_d *tree_ann_t;
 295 typedef struct var_ann_d *var_ann_t;
 296 typedef struct stmt_ann_d *stmt_ann_t;
 297
 298 static inline tree_ann_t tree_ann (tree);
 299 static inline tree_ann_t get_tree_ann (tree);
 300 static inline var_ann_t var_ann (tree);
 301 static inline var_ann_t get_var_ann (tree);
 302 static inline stmt_ann_t stmt_ann (tree);
 303 static inline stmt_ann_t get_stmt_ann (tree);
 304 static inline enum tree_ann_type ann_type (tree_ann_t);
 305 static inline basic_block bb_for_stmt (tree);
 306 extern void set_bb_for_stmt (tree, basic_block);
 307 static inline void modify_stmt (tree);
 308 static inline void unmodify_stmt (tree);
 309 static inline bool stmt_modified_p (tree);
 310 static inline varray_type may_aliases (tree);
 311 static inline int get_lineno (tree);
 312 static inline const char *get_filename (tree);
 313 static inline bool is_exec_stmt (tree);
 314 static inline bool is_label_stmt (tree);
 315 static inline v_may_def_optype get_v_may_def_ops (stmt_ann_t);
 316 static inline vuse_optype get_vuse_ops (stmt_ann_t);
 317 static inline use_optype get_use_ops (stmt_ann_t);
 318 static inline def_optype get_def_ops (stmt_ann_t);
 319 static inline bitmap addresses_taken (tree);
 320 static inline int num_immediate_uses (dataflow_t);
 321 static inline tree immediate_use (dataflow_t, int);
 322 static inline dataflow_t get_immediate_uses (tree);
 323 static inline void set_default_def (tree, tree);
 324 static inline tree default_def (tree);
 325
 326 /*---------------------------------------------------------------------------
 327                   Structure representing predictions in tree level.
 328 ---------------------------------------------------------------------------*/
 329 struct edge_prediction GTY((chain_next ("%h.next")))
 330 {
 331   struct edge_prediction *next;
 332   edge edge;
 333   enum br_predictor predictor;
 334   int probability;
 335 };
 336
 337 /*---------------------------------------------------------------------------
 338                   Block annotations stored in basic_block.tree_annotations
 339 ---------------------------------------------------------------------------*/
 340 struct bb_ann_d GTY(())
 341 {
 342   /* Chain of PHI nodes for this block.  */
 343   tree phi_nodes;
 344
 345   /* Nonzero if this block is forwardable during cfg cleanups.  This is also
 346      used to detect loops during cfg cleanups.  */
 347   unsigned forwardable: 1;
 348
 349   /* Nonzero if this block contains an escape point (see is_escape_site).  */
 350   unsigned has_escape_site : 1;
 351
 352   /* Nonzero if one or more incoming edges to this block should be threaded
 353      to an outgoing edge of this block.  */
 354   unsigned incoming_edge_threaded : 1;
 355
 356   struct edge_prediction *predictions;
 357 };
 358
 359 typedef struct bb_ann_d *bb_ann_t;
 360
 361 /* Accessors for basic block annotations.  */
 362 static inline bb_ann_t bb_ann (basic_block);
 363 static inline tree phi_nodes (basic_block);
 364 static inline void set_phi_nodes (basic_block, tree);
 365
 366 /*---------------------------------------------------------------------------
 367                               Global declarations
 368 ---------------------------------------------------------------------------*/
 369 /* Array of all variables referenced in the function.  */
 370 extern GTY(()) varray_type referenced_vars;
 371
 372 #define num_referenced_vars VARRAY_ACTIVE_SIZE (referenced_vars)
 373 #define referenced_var(i) VARRAY_TREE (referenced_vars, i)
 374
 375 /* Array of all SSA_NAMEs used in the function.  */
 376 extern GTY(()) varray_type ssa_names;
 377
 378 #define num_ssa_names VARRAY_ACTIVE_SIZE (ssa_names)
 379 #define ssa_name(i) VARRAY_TREE (ssa_names, i)
 380
 381 /* Artificial variable used to model the effects of function calls.  */
 382 extern GTY(()) tree global_var;
 383
 384 /* Call clobbered variables in the function.  If bit I is set, then
 385    REFERENCED_VARS (I) is call-clobbered.  */
 386 extern bitmap call_clobbered_vars;
 387
 388 /* Addressable variables in the function.  If bit I is set, then
 389    REFERENCED_VARS (I) has had its address taken.  */
 390 extern bitmap addressable_vars;
 391
 392 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 393 extern bool aliases_computed_p;
 394
 395 /* Macros for showing usage statistics.  */
 396 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 397                   ? (x)                                 \
 398                   : ((x) < 1024*1024*10                 \
 399                      ? (x) / 1024                       \
 400                      : (x) / (1024*1024))))
 401
 402 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 403
 404 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 405
 406
 407 /*---------------------------------------------------------------------------
 408                               Block iterators
 409 ---------------------------------------------------------------------------*/
 410
 411 typedef struct {
 412   tree_stmt_iterator tsi;
 413   basic_block bb;
 414 } block_stmt_iterator;
 415
 416 static inline block_stmt_iterator bsi_start (basic_block);
 417 static inline block_stmt_iterator bsi_last (basic_block);
 418 static inline block_stmt_iterator bsi_after_labels (basic_block);
 419 block_stmt_iterator stmt_for_bsi (tree);
 420 static inline bool bsi_end_p (block_stmt_iterator);
 421 static inline void bsi_next (block_stmt_iterator *);
 422 static inline void bsi_prev (block_stmt_iterator *);
 423 static inline tree bsi_stmt (block_stmt_iterator);
 424 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 425
 426 extern void bsi_remove (block_stmt_iterator *);
 427 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 428 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 429 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 430
 431 enum bsi_iterator_update
 432 {
 433   /* Note that these are intentionally in the same order as TSI_FOO.  They
 434      mean exactly the same as their TSI_* counterparts.  */
 435   BSI_NEW_STMT,
 436   BSI_SAME_STMT,
 437   BSI_CHAIN_START,
 438   BSI_CHAIN_END,
 439   BSI_CONTINUE_LINKING
 440 };
 441
 442 extern void bsi_insert_before (block_stmt_iterator *, tree,
 443                                enum bsi_iterator_update);
 444 extern void bsi_insert_after (block_stmt_iterator *, tree,
 445                               enum bsi_iterator_update);
 446
 447 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 448
 449 /*---------------------------------------------------------------------------
 450                               Function prototypes
 451 ---------------------------------------------------------------------------*/
 452 /* In tree-cfg.c  */
 453
 454 /* Location to track pending stmt for edge insertion.  */
 455 #define PENDING_STMT(e) ((e)->insns.t)
 456
 457 extern void delete_tree_cfg_annotations (void);
 458 extern void disband_implicit_edges (void);
 459 extern bool stmt_ends_bb_p (tree);
 460 extern bool is_ctrl_stmt (tree);
 461 extern bool is_ctrl_altering_stmt (tree);
 462 extern bool computed_goto_p (tree);
 463 extern bool simple_goto_p (tree);
 464 extern void tree_dump_bb (basic_block, FILE *, int);
 465 extern void debug_tree_bb (basic_block);
 466 extern basic_block debug_tree_bb_n (int);
 467 extern void dump_tree_cfg (FILE *, int);
 468 extern void debug_tree_cfg (int);
 469 extern void dump_cfg_stats (FILE *);
 470 extern void debug_cfg_stats (void);
 471 extern void debug_loop_ir (void);
 472 extern void print_loop_ir (FILE *);
 473 extern void cleanup_dead_labels (void);
 474 extern void group_case_labels (void);
 475 extern bool cleanup_tree_cfg (void);
 476 extern tree first_stmt (basic_block);
 477 extern tree last_stmt (basic_block);
 478 extern tree *last_stmt_ptr (basic_block);
 479 extern tree last_and_only_stmt (basic_block);
 480 extern edge find_taken_edge (basic_block, tree);
 481 extern void cfg_remove_useless_stmts (void);
 482 extern edge thread_edge (edge, basic_block);
 483 extern basic_block label_to_block (tree);
 484 extern void tree_optimize_tail_calls (bool, enum tree_dump_index);
 485 extern edge tree_block_forwards_to (basic_block bb);
 486 extern void bsi_insert_on_edge (edge, tree);
 487 extern basic_block bsi_insert_on_edge_immediate (edge, tree);
 488 extern void bsi_commit_edge_inserts (int *);
 489 extern void notice_special_calls (tree);
 490 extern void clear_special_calls (void);
 491 extern void verify_stmts (void);
 492 extern tree tree_block_label (basic_block bb);
 493 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 494 extern bool tree_duplicate_sese_region (edge, edge, basic_block *, unsigned,
 495                                         basic_block *);
 496 extern void add_phi_args_after_copy_bb (basic_block);
 497 extern void add_phi_args_after_copy (basic_block *, unsigned);
 498 extern void rewrite_to_new_ssa_names_bb (basic_block, struct htab *);
 499 extern void rewrite_to_new_ssa_names (basic_block *, unsigned, htab_t);
 500 extern void allocate_ssa_names (bitmap, struct htab **);
 501 extern bool tree_purge_dead_eh_edges (basic_block);
 502 extern bool tree_purge_all_dead_eh_edges (bitmap);
 503 extern tree gimplify_val (block_stmt_iterator *, tree, tree);
 504 extern tree gimplify_build1 (block_stmt_iterator *, enum tree_code,
 505                              tree, tree);
 506 extern tree gimplify_build2 (block_stmt_iterator *, enum tree_code,
 507                              tree, tree, tree);
 508 extern tree gimplify_build3 (block_stmt_iterator *, enum tree_code,
 509                              tree, tree, tree, tree);
 510
 511 /* In tree-pretty-print.c.  */
 512 extern void dump_generic_bb (FILE *, basic_block, int, int);
 513
 514 /* In tree-dfa.c  */
 515 extern var_ann_t create_var_ann (tree);
 516 extern stmt_ann_t create_stmt_ann (tree);
 517 extern tree_ann_t create_tree_ann (tree);
 518 extern tree create_phi_node (tree, basic_block);
 519 extern void add_phi_arg (tree *, tree, edge);
 520 extern void remove_phi_arg (tree, basic_block);
 521 extern void remove_phi_arg_num (tree, int);
 522 extern void remove_phi_node (tree, tree, basic_block);
 523 extern void remove_all_phi_nodes_for (bitmap);
 524 extern void dump_dfa_stats (FILE *);
 525 extern void debug_dfa_stats (void);
 526 extern void debug_referenced_vars (void);
 527 extern void dump_referenced_vars (FILE *);
 528 extern void dump_variable (FILE *, tree);
 529 extern void debug_variable (tree);
 530 extern void dump_immediate_uses (FILE *);
 531 extern void debug_immediate_uses (void);
 532 extern void dump_immediate_uses_for (FILE *, tree);
 533 extern void debug_immediate_uses_for (tree);
 534 extern void compute_immediate_uses (int, bool (*)(tree));
 535 extern void free_df (void);
 536 extern void free_df_for_stmt (tree);
 537 extern tree get_virtual_var (tree);
 538 extern void add_referenced_tmp_var (tree var);
 539 extern void mark_new_vars_to_rename (tree, bitmap);
 540 extern void find_new_referenced_vars (tree *);
 541
 542 extern void redirect_immediate_uses (tree, tree);
 543 extern tree make_rename_temp (tree, const char *);
 544
 545 /* Flags used when computing reaching definitions and reached uses.  */
 546 #define TDFA_USE_OPS            1 << 0
 547 #define TDFA_USE_VOPS           1 << 1
 548
 549 /* In gimple-low.c  */
 550 struct lower_data;
 551 extern void lower_stmt_body (tree, struct lower_data *);
 552 extern void record_vars (tree);
 553 extern bool block_may_fallthru (tree block);
 554
 555 /* In tree-ssa-alias.c  */
 556 extern void dump_may_aliases_for (FILE *, tree);
 557 extern void debug_may_aliases_for (tree);
 558 extern void dump_alias_info (FILE *);
 559 extern void debug_alias_info (void);
 560 extern void dump_points_to_info (FILE *);
 561 extern void debug_points_to_info (void);
 562 extern void dump_points_to_info_for (FILE *, tree);
 563 extern void debug_points_to_info_for (tree);
 564 extern bool may_be_aliased (tree);
 565
 566 /* Call-back function for walk_use_def_chains().  At each reaching
 567    definition, a function with this prototype is called.  */
 568 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 569
 570 /* In tree-ssa.c  */
 571 extern void init_tree_ssa (void);
 572 extern void dump_reaching_defs (FILE *);
 573 extern void debug_reaching_defs (void);
 574 extern void dump_tree_ssa (FILE *);
 575 extern void debug_tree_ssa (void);
 576 extern void debug_def_blocks (void);
 577 extern void dump_tree_ssa_stats (FILE *);
 578 extern void debug_tree_ssa_stats (void);
 579 extern void ssa_remove_edge (edge);
 580 extern edge ssa_redirect_edge (edge, basic_block);
 581 extern bool tree_ssa_useless_type_conversion (tree);
 582 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 583 extern void verify_ssa (void);
 584 extern void delete_tree_ssa (void);
 585 extern void register_new_def (tree, varray_type *);
 586 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *, bool);
 587 extern void kill_redundant_phi_nodes (void);
 588
 589 /* In tree-into-ssa.c  */
 590 extern void rewrite_into_ssa (bool);
 591 extern void rewrite_ssa_into_ssa (void);
 592
 593 void compute_global_livein (bitmap, bitmap);
 594 tree duplicate_ssa_name (tree, tree);
 595
 596 /* In tree-ssa-ccp.c  */
 597 bool fold_stmt (tree *);
 598 tree widen_bitfield (tree, tree, tree);
 599
 600 /* In tree-ssa-dom.c  */
 601 extern void dump_dominator_optimization_stats (FILE *);
 602 extern void debug_dominator_optimization_stats (void);
 603
 604 /* In tree-ssa-copy.c  */
 605 extern void propagate_value (use_operand_p, tree);
 606 extern void propagate_tree_value (tree *, tree);
 607 extern void replace_exp (use_operand_p, tree);
 608 extern bool may_propagate_copy (tree, tree);
 609 extern bool may_propagate_copy_into_asm (tree);
 610
 611 /* Description of number of iterations of a loop.  All the expressions inside
 612    the structure can be evaluated at the end of the loop's preheader
 613    (and due to ssa form, also anywhere inside the body of the loop).  */
 614
 615 struct tree_niter_desc
 616 {
 617   tree assumptions;     /* The boolean expression.  If this expression evaluates
 618                            to false, then the other fields in this structure
 619                            should not be used; there is no guarantee that they
 620                            will be correct.  */
 621   tree may_be_zero;     /* The boolean expression.  If it evaluates to true,
 622                            the loop will exit in the first iteration (i.e.
 623                            its latch will not be executed), even if the niter
 624                            field says otherwise.  */
 625   tree niter;           /* The expression giving the number of iterations of
 626                            a loop (provided that assumptions == true and
 627                            may_be_zero == false), more precisely the number
 628                            of executions of the latch of the loop.  */
 629   tree additional_info; /* The boolean expression.  Sometimes we use additional
 630                            knowledge to simplify the other expressions
 631                            contained in this structure (for example the
 632                            knowledge about value ranges of operands on entry to
 633                            the loop).  If this is a case, conjunction of such
 634                            condition is stored in this field, so that we do not
 635                            lose the information: for example if may_be_zero
 636                            is (n <= 0) and niter is (unsigned) n, we know
 637                            that the number of iterations is at most
 638                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 639                            is eliminated (by looking at the guard on entry of
 640                            the loop), then the information would be lost.  */
 641 };
 642
 643 /* In tree-vectorizer.c */
 644 void vectorize_loops (struct loops *);
 645
 646 /* In tree-ssa-phiopt.c */
 647 bool empty_block_p (basic_block);
 648
 649 /* In tree-ssa-loop*.c  */
 650
 651 void tree_ssa_lim (struct loops *);
 652 void tree_ssa_unswitch_loops (struct loops *);
 653 void canonicalize_induction_variables (struct loops *);
 654 void tree_unroll_loops_completely (struct loops *);
 655 void tree_ssa_iv_optimize (struct loops *);
 656
 657 void number_of_iterations_cond (tree, tree, tree, enum tree_code, tree, tree,
 658                                 struct tree_niter_desc *);
 659 bool number_of_iterations_exit (struct loop *, edge,
 660                                 struct tree_niter_desc *niter);
 661 tree loop_niter_by_eval (struct loop *, edge);
 662 tree find_loop_niter_by_eval (struct loop *, edge *);
 663 void estimate_numbers_of_iterations (struct loops *);
 664 tree can_count_iv_in_wider_type (struct loop *, tree, tree, tree, tree);
 665 void free_numbers_of_iterations_estimates (struct loops *);
 666 void rewrite_into_loop_closed_ssa (void);
 667 void verify_loop_closed_ssa (void);
 668 void loop_commit_inserts (void);
 669 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 670 void create_iv (tree, tree, tree, struct loop *, block_stmt_iterator *, bool,
 671                 tree *, tree *);
 672 void split_loop_exit_edge (edge);
 673 basic_block bsi_insert_on_edge_immediate_loop (edge, tree);
 674 void standard_iv_increment_position (struct loop *, block_stmt_iterator *,
 675                                      bool *);
 676 basic_block ip_end_pos (struct loop *);
 677 basic_block ip_normal_pos (struct loop *);
 678 bool tree_duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
 679                                          unsigned int, sbitmap,
 680                                          edge, edge *,
 681                                          unsigned int *, int);
 682 struct loop *tree_ssa_loop_version (struct loops *, struct loop *, tree,
 683                                     basic_block *);
 684
 685 /* In tree-ssa-loop-im.c  */
 686 /* The possibilities of statement movement.  */
 687
 688 enum move_pos
 689   {
 690     MOVE_IMPOSSIBLE,            /* No movement -- side effect expression.  */
 691     MOVE_PRESERVE_EXECUTION,    /* Must not cause the non-executed statement
 692                                    become executed -- memory accesses, ... */
 693     MOVE_POSSIBLE               /* Unlimited movement.  */
 694   };
 695 extern enum move_pos movement_possibility (tree);
 696
 697 /* In tree-if-conv.c  */
 698 bool tree_if_conversion (struct loop *, bool);
 699
 700
 701 /* In tree-flow-inline.h  */
 702 static inline int phi_arg_from_edge (tree, edge);
 703 static inline bool is_call_clobbered (tree);
 704 static inline void mark_call_clobbered (tree);
 705 static inline void set_is_used (tree);
 706
 707 /* In tree-eh.c  */
 708 extern void make_eh_edges (tree);
 709 extern bool tree_could_trap_p (tree);
 710 extern bool tree_could_throw_p (tree);
 711 extern bool tree_can_throw_internal (tree);
 712 extern bool tree_can_throw_external (tree);
 713 extern int lookup_stmt_eh_region (tree);
 714 extern void add_stmt_to_eh_region (tree, int);
 715 extern bool remove_stmt_from_eh_region (tree);
 716 extern bool maybe_clean_eh_stmt (tree);
 717
 718 /* In tree-ssa-pre.c  */
 719 void add_to_value (tree, tree);
 720 void debug_value_expressions (tree);
 721 void print_value_expressions (FILE *, tree);
 722
 723
 724 /* In tree-vn.c  */
 725 bool expressions_equal_p (tree, tree);
 726 tree get_value_handle (tree);
 727 hashval_t vn_compute (tree, hashval_t, vuse_optype);
 728 tree vn_lookup_or_add (tree, vuse_optype);
 729 void vn_add (tree, tree, vuse_optype);
 730 tree vn_lookup (tree, vuse_optype);
 731 void vn_init (void);
 732 void vn_delete (void);
 733
 734
 735 /* In tree-sra.c  */
 736 void insert_edge_copies (tree stmt, basic_block bb);
 737
 738 /* In tree-ssa-operands.c  */
 739 extern void build_ssa_operands (tree, stmt_ann_t, stmt_operands_p,
 740                                 stmt_operands_p);
 741
 742 /* In tree-loop-linear.c  */
 743 extern void linear_transform_loops (struct loops *);
 744
 745 /* In gimplify.c  */
 746
 747 tree force_gimple_operand (tree, tree *, bool, tree);
 748
 749 #include "tree-flow-inline.h"
 750
 751 #endif /* _TREE_FLOW_H  */