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
  32 /* Forward declare structures for the garbage collector GTY markers.  */
  33 #ifndef GCC_BASIC_BLOCK_H
  34 struct edge_def;
  35 typedef struct edge_def *edge;
  36 struct basic_block_def;
  37 typedef struct basic_block_def *basic_block;
  38 #endif
  39
  40 /*---------------------------------------------------------------------------
  41                       Attributes for SSA_NAMEs.
  42
  43   NOTE: These structures are stored in struct tree_ssa_name
  44   but are only used by the tree optimizers, so it makes better sense
  45   to declare them here to avoid recompiling unrelated files when
  46   making changes.
  47 ---------------------------------------------------------------------------*/
  48
  49 /* Aliasing information for SSA_NAMEs representing pointer variables.  */
  50 struct ptr_info_def GTY(())
  51 {
  52   /* Nonzero if points-to analysis couldn't determine where this pointer
  53      is pointing to.  */
  54   unsigned int pt_anything : 1;
  55
  56   /* Nonzero if this pointer is the result of a call to malloc.  */
  57   unsigned int pt_malloc : 1;
  58
  59   /* Nonzero if the value of this pointer escapes the current function.  */
  60   unsigned int value_escapes_p : 1;
  61
  62   /* Nonzero if this pointer is dereferenced.  */
  63   unsigned int is_dereferenced : 1;
  64
  65   /* Set of variables that this pointer may point to.  */
  66   bitmap pt_vars;
  67
  68   /* If this pointer has been dereferenced, and points-to information is
  69      more precise than type-based aliasing, indirect references to this
  70      pointer will be represented by this memory tag, instead of the type
  71      tag computed by TBAA.  */
  72   tree name_mem_tag;
  73 };
  74
  75
  76 /*---------------------------------------------------------------------------
  77                    Tree annotations stored in tree_common.ann
  78 ---------------------------------------------------------------------------*/
  79 enum tree_ann_type { TREE_ANN_COMMON, VAR_ANN, STMT_ANN };
  80
  81 struct tree_ann_common_d GTY(())
  82 {
  83   /* Annotation type.  */
  84   enum tree_ann_type type;
  85
  86  /* Auxiliary info specific to a pass.  At all times, this
  87     should either point to valid data or be NULL.  */
  88   PTR GTY ((skip (""))) aux;
  89
  90   /* The value handle for this expression.  Used by GVN-PRE.  */
  91   tree GTY((skip)) value_handle;
  92 };
  93
  94 /* It is advantageous to avoid things like life analysis for variables which
  95    do not need PHI nodes.  This enum describes whether or not a particular
  96    variable may need a PHI node.  */
  97
  98 enum need_phi_state {
  99   /* This is the default.  If we are still in this state after finding
 100      all the definition and use sites, then we will assume the variable
 101      needs PHI nodes.  This is probably an overly conservative assumption.  */
 102   NEED_PHI_STATE_UNKNOWN,
 103
 104   /* This state indicates that we have seen one or more sets of the
 105      variable in a single basic block and that the sets dominate all
 106      uses seen so far.  If after finding all definition and use sites
 107      we are still in this state, then the variable does not need any
 108      PHI nodes.  */
 109   NEED_PHI_STATE_NO,
 110
 111   /* This state indicates that we have either seen multiple definitions of
 112      the variable in multiple blocks, or that we encountered a use in a
 113      block that was not dominated by the block containing the set(s) of
 114      this variable.  This variable is assumed to need PHI nodes.  */
 115   NEED_PHI_STATE_MAYBE
 116 };
 117
 118
 119 /* When computing aliasing information, we represent the memory pointed-to
 120    by pointers with artificial variables called "memory tags" (MT).  There
 121    are two kinds of tags: type and name.  Type tags (TMT) are used in
 122    type-based alias analysis, they represent all the pointed-to locations
 123    and variables of the same alias set class.  Name tags (NMT) are used in
 124    flow-sensitive points-to alias analysis, they represent the variables
 125    and memory locations pointed-to by a specific SSA_NAME pointer.  */
 126 enum mem_tag_kind {
 127   /* This variable is not a memory tag.  */
 128   NOT_A_TAG,
 129
 130   /* This variable is a type memory tag (TMT).  */
 131   TYPE_TAG,
 132
 133   /* This variable is a name memory tag (NMT).  */
 134   NAME_TAG
 135 };
 136
 137 struct var_ann_d GTY(())
 138 {
 139   struct tree_ann_common_d common;
 140
 141   /* Used by the out of SSA pass to determine whether this variable has
 142      been seen yet or not.  */
 143   unsigned out_of_ssa_tag : 1;
 144
 145   /* Used when building root_var structures in tree_ssa_live.[ch].  */
 146   unsigned root_var_processed : 1;
 147
 148   /* If nonzero, this variable is a memory tag.  */
 149   ENUM_BITFIELD (mem_tag_kind) mem_tag_kind : 2;
 150
 151   /* Nonzero if this variable is an alias tag that represents references to
 152      other variables (i.e., this variable appears in the MAY_ALIASES array
 153      of other variables).  */
 154   unsigned is_alias_tag : 1;
 155
 156   /* Nonzero if this variable was used after SSA optimizations were
 157      applied.  We set this when translating out of SSA form.  */
 158   unsigned used : 1;
 159
 160   /* This field indicates whether or not the variable may need PHI nodes.
 161      See the enum's definition for more detailed information about the
 162      states.  */
 163   ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
 164
 165   /* An artificial variable representing the memory location pointed-to by
 166      all the pointers that TBAA (type-based alias analysis) considers
 167      to be aliased.  If the variable is not a pointer or if it is never
 168      dereferenced, this must be NULL.  */
 169   tree type_mem_tag;
 170
 171   /* Variables that may alias this variable.  */
 172   varray_type may_aliases;
 173
 174   /* Unique ID of this variable.  */
 175   size_t uid;
 176
 177   /* Used when going out of SSA form to indicate which partition this
 178      variable represents storage for.  */
 179   unsigned partition;
 180
 181   /* Used by the root-var object in tree-ssa-live.[ch].  */
 182   unsigned root_index;
 183
 184   /* Default definition for this symbol.  If this field is not NULL, it
 185      means that the first reference to this variable in the function is a
 186      USE or a VUSE.  In those cases, the SSA renamer creates an SSA name
 187      for this variable with an empty defining statement.  */
 188   tree default_def;
 189
 190   /* During into-ssa and the dominator optimizer, this field holds the
 191      current version of this variable (an SSA_NAME).
 192
 193      This was previously two varrays (one in into-ssa the other in the
 194      dominator optimizer).  That is wasteful, particularly since the
 195      dominator optimizer calls into-ssa resulting in having two varrays
 196      live at the same time and this can happen for each call to the
 197      dominator optimizer.  */
 198   tree current_def;
 199 };
 200
 201
 202 struct dataflow_d GTY(())
 203 {
 204   /* Immediate uses.  This is a list of all the statements and PHI nodes
 205      that are immediately reached by the definitions made in this
 206      statement.  */
 207   varray_type immediate_uses;
 208
 209   /* Use this array for very small numbers of uses instead of the varray.  */
 210   tree uses[2];
 211
 212   /* Reached uses.  This is a list of all the possible program statements
 213      that may be reached directly or indirectly by definitions made in this
 214      statement.  Notice that this is a superset of IMMEDIATE_USES.
 215      For instance, given the following piece of code:
 216
 217             1   a1 = 10;
 218             2   if (a1 > 3)
 219             3     a2 = a1 + 5;
 220             4   a3 = PHI (a1, a2)
 221             5   b1 = a3 - 2;
 222
 223      IMMEDIATE_USES for statement #1 are all those statements that use a1
 224      directly (i.e., #2, #3 and #4).  REACHED_USES for statement #1 also
 225      includes statement #5 because 'a1' could reach 'a3' via the PHI node
 226      at statement #4.  The set of REACHED_USES is then the transitive
 227      closure over all the PHI nodes in the IMMEDIATE_USES set.  */
 228
 229   /* Reaching definitions.  Similarly to REACHED_USES, the set
 230      REACHING_DEFS is the set of all the statements that make definitions
 231      that may reach this statement.  Notice that we don't need to have a
 232      similar entry for immediate definitions, as these are represented by
 233      the SSA_NAME nodes themselves (each SSA_NAME node contains a pointer
 234      to the statement that makes that definition).  */
 235 };
 236
 237 typedef struct dataflow_d *dataflow_t;
 238
 239
 240 struct stmt_ann_d GTY(())
 241 {
 242   struct tree_ann_common_d common;
 243
 244   /* Nonzero if the statement has been modified (meaning that the operands
 245      need to be scanned again).  */
 246   unsigned modified : 1;
 247
 248   /* Nonzero if the statement is in the CCP worklist and has not been
 249      "cancelled".  If we ever need to use this bit outside CCP, then
 250      it should be renamed.  */
 251   unsigned in_ccp_worklist: 1;
 252
 253   /* Nonzero if the statement makes aliased loads.  */
 254   unsigned makes_aliased_loads : 1;
 255
 256   /* Nonzero if the statement makes aliased stores.  */
 257   unsigned makes_aliased_stores : 1;
 258
 259   /* Nonzero if the statement makes references to volatile storage.  */
 260   unsigned has_volatile_ops : 1;
 261
 262   /* Nonzero if the statement makes a function call that may clobber global
 263      and local addressable variables.  */
 264   unsigned makes_clobbering_call : 1;
 265
 266   /* Basic block that contains this statement.  */
 267   basic_block GTY ((skip (""))) bb;
 268
 269   /* Statement operands.  */
 270   struct def_optype_d * GTY (()) def_ops;
 271   struct use_optype_d * GTY (()) use_ops;
 272
 273   /* Virtual operands (V_MAY_DEF, VUSE, and V_MUST_DEF).  */
 274   struct v_may_def_optype_d * GTY (()) v_may_def_ops;
 275   struct vuse_optype_d * GTY (()) vuse_ops;
 276   struct v_must_def_optype_d * GTY (()) v_must_def_ops;
 277
 278   /* Dataflow information.  */
 279   dataflow_t df;
 280
 281   /* Set of variables that have had their address taken in the statement.  */
 282   bitmap addresses_taken;
 283
 284   /* Unique identifier for this statement.  These ID's are to be created
 285      by each pass on an as-needed basis in any order convenient for the
 286      pass which needs statement UIDs.  */
 287   unsigned int uid;
 288 };
 289
 290 union tree_ann_d GTY((desc ("ann_type ((tree_ann_t)&%h)")))
 291 {
 292   struct tree_ann_common_d GTY((tag ("TREE_ANN_COMMON"))) common;
 293   struct var_ann_d GTY((tag ("VAR_ANN"))) decl;
 294   struct stmt_ann_d GTY((tag ("STMT_ANN"))) stmt;
 295 };
 296
 297 typedef union tree_ann_d *tree_ann_t;
 298 typedef struct var_ann_d *var_ann_t;
 299 typedef struct stmt_ann_d *stmt_ann_t;
 300
 301 static inline tree_ann_t tree_ann (tree);
 302 static inline tree_ann_t get_tree_ann (tree);
 303 static inline var_ann_t var_ann (tree);
 304 static inline var_ann_t get_var_ann (tree);
 305 static inline stmt_ann_t stmt_ann (tree);
 306 static inline stmt_ann_t get_stmt_ann (tree);
 307 static inline enum tree_ann_type ann_type (tree_ann_t);
 308 static inline basic_block bb_for_stmt (tree);
 309 extern void set_bb_for_stmt (tree, basic_block);
 310 static inline void modify_stmt (tree);
 311 static inline void unmodify_stmt (tree);
 312 static inline bool stmt_modified_p (tree);
 313 static inline varray_type may_aliases (tree);
 314 static inline int get_lineno (tree);
 315 static inline const char *get_filename (tree);
 316 static inline bool is_exec_stmt (tree);
 317 static inline bool is_label_stmt (tree);
 318 static inline v_may_def_optype get_v_may_def_ops (stmt_ann_t);
 319 static inline vuse_optype get_vuse_ops (stmt_ann_t);
 320 static inline use_optype get_use_ops (stmt_ann_t);
 321 static inline def_optype get_def_ops (stmt_ann_t);
 322 static inline bitmap addresses_taken (tree);
 323 static inline int num_immediate_uses (dataflow_t);
 324 static inline tree immediate_use (dataflow_t, int);
 325 static inline dataflow_t get_immediate_uses (tree);
 326 static inline void set_default_def (tree, tree);
 327 static inline tree default_def (tree);
 328 static inline bool may_be_aliased (tree);
 329
 330 /*---------------------------------------------------------------------------
 331                   Structure representing predictions in tree level.
 332 ---------------------------------------------------------------------------*/
 333 struct edge_prediction GTY((chain_next ("%h.next")))
 334 {
 335   struct edge_prediction *next;
 336   edge edge;
 337   enum br_predictor predictor;
 338   int probability;
 339 };
 340
 341 /*---------------------------------------------------------------------------
 342                   Block annotations stored in basic_block.tree_annotations
 343 ---------------------------------------------------------------------------*/
 344 struct bb_ann_d GTY(())
 345 {
 346   /* Chain of PHI nodes for this block.  */
 347   tree phi_nodes;
 348
 349   /* Number of predecessors for this block.  This is only valid during
 350      SSA rewriting.  It is not maintained after conversion into SSA form.  */
 351   int num_preds;
 352
 353   /* Nonzero if this block is forwardable during cfg cleanups.  This is also
 354      used to detect loops during cfg cleanups.  */
 355   unsigned forwardable: 1;
 356
 357   /* Nonzero if this block contains an escape point (see is_escape_site).  */
 358   unsigned has_escape_site : 1;
 359
 360   struct edge_prediction *predictions;
 361 };
 362
 363 typedef struct bb_ann_d *bb_ann_t;
 364
 365 /* Accessors for basic block annotations.  */
 366 static inline bb_ann_t bb_ann (basic_block);
 367 static inline tree phi_nodes (basic_block);
 368 static inline void set_phi_nodes (basic_block, tree);
 369
 370 /*---------------------------------------------------------------------------
 371                               Global declarations
 372 ---------------------------------------------------------------------------*/
 373 /* Array of all variables referenced in the function.  */
 374 extern GTY(()) varray_type referenced_vars;
 375
 376 #define num_referenced_vars VARRAY_ACTIVE_SIZE (referenced_vars)
 377 #define referenced_var(i) VARRAY_TREE (referenced_vars, i)
 378
 379 /* Array of all SSA_NAMEs used in the function.  */
 380 extern GTY(()) varray_type ssa_names;
 381
 382 #define num_ssa_names VARRAY_ACTIVE_SIZE (ssa_names)
 383 #define ssa_name(i) VARRAY_TREE (ssa_names, i)
 384
 385 /* Artificial variable used to model the effects of function calls.  */
 386 extern GTY(()) tree global_var;
 387
 388 /* Call clobbered variables in the function.  If bit I is set, then
 389    REFERENCED_VARS (I) is call-clobbered.  */
 390 extern bitmap call_clobbered_vars;
 391
 392 /* Addressable variables in the function.  If bit I is set, then
 393    REFERENCED_VARS (I) has had its address taken.  */
 394 extern bitmap addressable_vars;
 395
 396 /* 'true' after aliases have been computed (see compute_may_aliases).  */
 397 extern bool aliases_computed_p;
 398
 399 /* Macros for showing usage statistics.  */
 400 #define SCALE(x) ((unsigned long) ((x) < 1024*10        \
 401                   ? (x)                                 \
 402                   : ((x) < 1024*1024*10                 \
 403                      ? (x) / 1024                       \
 404                      : (x) / (1024*1024))))
 405
 406 #define LABEL(x) ((x) < 1024*10 ? 'b' : ((x) < 1024*1024*10 ? 'k' : 'M'))
 407
 408 #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
 409
 410
 411 /*---------------------------------------------------------------------------
 412                               Block iterators
 413 ---------------------------------------------------------------------------*/
 414
 415 typedef struct {
 416   tree_stmt_iterator tsi;
 417   basic_block bb;
 418 } block_stmt_iterator;
 419
 420 static inline block_stmt_iterator bsi_start (basic_block);
 421 static inline block_stmt_iterator bsi_last (basic_block);
 422 static inline block_stmt_iterator bsi_after_labels (basic_block);
 423 static inline bool bsi_end_p (block_stmt_iterator);
 424 static inline void bsi_next (block_stmt_iterator *);
 425 static inline void bsi_prev (block_stmt_iterator *);
 426 static inline tree bsi_stmt (block_stmt_iterator);
 427 static inline tree * bsi_stmt_ptr (block_stmt_iterator);
 428
 429 extern void bsi_remove (block_stmt_iterator *);
 430 extern void bsi_move_before (block_stmt_iterator *, block_stmt_iterator *);
 431 extern void bsi_move_after (block_stmt_iterator *, block_stmt_iterator *);
 432 extern void bsi_move_to_bb_end (block_stmt_iterator *, basic_block);
 433
 434 enum bsi_iterator_update
 435 {
 436   /* Note that these are intentionally in the same order as TSI_FOO.  They
 437      mean exactly the same as their TSI_* counterparts.  */
 438   BSI_NEW_STMT,
 439   BSI_SAME_STMT,
 440   BSI_CHAIN_START,
 441   BSI_CHAIN_END,
 442   BSI_CONTINUE_LINKING
 443 };
 444
 445 extern void bsi_insert_before (block_stmt_iterator *, tree,
 446                                enum bsi_iterator_update);
 447 extern void bsi_insert_after (block_stmt_iterator *, tree,
 448                               enum bsi_iterator_update);
 449
 450 extern void bsi_replace (const block_stmt_iterator *, tree, bool);
 451
 452 /*---------------------------------------------------------------------------
 453                               Function prototypes
 454 ---------------------------------------------------------------------------*/
 455 /* In tree-cfg.c  */
 456
 457 /* Location to track pending stmt for edge insertion.  */
 458 #define PENDING_STMT(e) ((e)->insns.t)
 459
 460 extern void delete_tree_cfg_annotations (void);
 461 extern void disband_implicit_edges (void);
 462 extern bool stmt_ends_bb_p (tree);
 463 extern bool is_ctrl_stmt (tree);
 464 extern bool is_ctrl_altering_stmt (tree);
 465 extern bool computed_goto_p (tree);
 466 extern bool simple_goto_p (tree);
 467 extern void tree_dump_bb (basic_block, FILE *, int);
 468 extern void debug_tree_bb (basic_block);
 469 extern basic_block debug_tree_bb_n (int);
 470 extern void dump_tree_cfg (FILE *, int);
 471 extern void debug_tree_cfg (int);
 472 extern void dump_cfg_stats (FILE *);
 473 extern void debug_cfg_stats (void);
 474 extern void debug_loop_ir (void);
 475 extern void print_loop_ir (FILE *);
 476 extern void cleanup_dead_labels (void);
 477 extern void group_case_labels (void);
 478 extern void cleanup_tree_cfg (void);
 479 extern tree first_stmt (basic_block);
 480 extern tree last_stmt (basic_block);
 481 extern tree *last_stmt_ptr (basic_block);
 482 extern tree last_and_only_stmt (basic_block);
 483 extern edge find_taken_edge (basic_block, tree);
 484 extern void cfg_remove_useless_stmts (void);
 485 extern edge thread_edge (edge, basic_block);
 486 extern basic_block label_to_block (tree);
 487 extern void tree_optimize_tail_calls (bool, enum tree_dump_index);
 488 extern edge tree_block_forwards_to (basic_block bb);
 489 extern void bsi_insert_on_edge (edge, tree);
 490 extern void bsi_commit_edge_inserts (int *);
 491 extern void notice_special_calls (tree);
 492 extern void clear_special_calls (void);
 493 extern void compute_dominance_frontiers (bitmap *);
 494 extern void verify_stmts (void);
 495 extern tree tree_block_label (basic_block bb);
 496 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 497 extern bool tree_purge_dead_eh_edges (basic_block);
 498 extern bool tree_purge_all_dead_eh_edges (bitmap);
 499
 500 /* In tree-pretty-print.c.  */
 501 extern void dump_generic_bb (FILE *, basic_block, int, int);
 502
 503 /* In tree-dfa.c  */
 504 extern var_ann_t create_var_ann (tree);
 505 extern stmt_ann_t create_stmt_ann (tree);
 506 extern tree_ann_t create_tree_ann (tree);
 507 extern tree create_phi_node (tree, basic_block);
 508 extern void add_phi_arg (tree *, tree, edge);
 509 extern void remove_phi_arg (tree, basic_block);
 510 extern void remove_phi_arg_num (tree, int);
 511 extern void remove_phi_node (tree, tree, basic_block);
 512 extern void remove_all_phi_nodes_for (bitmap);
 513 extern void dump_dfa_stats (FILE *);
 514 extern void debug_dfa_stats (void);
 515 extern void debug_referenced_vars (void);
 516 extern void dump_referenced_vars (FILE *);
 517 extern void dump_variable (FILE *, tree);
 518 extern void debug_variable (tree);
 519 extern void dump_immediate_uses (FILE *);
 520 extern void debug_immediate_uses (void);
 521 extern void dump_immediate_uses_for (FILE *, tree);
 522 extern void debug_immediate_uses_for (tree);
 523 extern void compute_immediate_uses (int, bool (*)(tree));
 524 extern void free_df (void);
 525 extern tree get_virtual_var (tree);
 526 extern void add_referenced_tmp_var (tree var);
 527 extern void mark_new_vars_to_rename (tree, bitmap);
 528 extern void redirect_immediate_uses (tree, tree);
 529 extern tree make_rename_temp (tree, const char *);
 530
 531 /* Flags used when computing reaching definitions and reached uses.  */
 532 #define TDFA_USE_OPS            1 << 0
 533 #define TDFA_USE_VOPS           1 << 1
 534
 535 /* In gimple-low.c  */
 536 struct lower_data;
 537 extern void lower_stmt_body (tree, struct lower_data *);
 538 extern void expand_used_vars (void);
 539 extern void record_vars (tree);
 540 extern bool block_may_fallthru (tree block);
 541
 542 /* In tree-ssa-alias.c  */
 543 extern void dump_may_aliases_for (FILE *, tree);
 544 extern void debug_may_aliases_for (tree);
 545 extern void dump_alias_info (FILE *);
 546 extern void debug_alias_info (void);
 547 extern void dump_points_to_info (FILE *);
 548 extern void debug_points_to_info (void);
 549 extern void dump_points_to_info_for (FILE *, tree);
 550 extern void debug_points_to_info_for (tree);
 551
 552 /* Call-back function for walk_use_def_chains().  At each reaching
 553    definition, a function with this prototype is called.  */
 554 typedef bool (*walk_use_def_chains_fn) (tree, tree, void *);
 555
 556 /* In tree-ssa.c  */
 557 extern void init_tree_ssa (void);
 558 extern void rewrite_vars_out_of_ssa (bitmap);
 559 extern void dump_reaching_defs (FILE *);
 560 extern void debug_reaching_defs (void);
 561 extern void dump_tree_ssa (FILE *);
 562 extern void debug_tree_ssa (void);
 563 extern void debug_def_blocks (void);
 564 extern void dump_tree_ssa_stats (FILE *);
 565 extern void debug_tree_ssa_stats (void);
 566 extern void ssa_remove_edge (edge);
 567 extern edge ssa_redirect_edge (edge, basic_block);
 568 extern void set_is_used (tree);
 569 extern bool tree_ssa_useless_type_conversion (tree);
 570 extern bool tree_ssa_useless_type_conversion_1 (tree, tree);
 571 extern void verify_ssa (void);
 572 extern void delete_tree_ssa (void);
 573 extern void register_new_def (tree, varray_type *);
 574 extern void walk_use_def_chains (tree, walk_use_def_chains_fn, void *);
 575 extern void kill_redundant_phi_nodes (void);
 576
 577 /* In tree-into-ssa.c  */
 578 extern void rewrite_into_ssa (bool);
 579 extern void rewrite_ssa_into_ssa (bitmap);
 580
 581 void compute_global_livein (bitmap, bitmap);
 582 tree duplicate_ssa_name (tree, tree);
 583
 584 /* In tree-ssa-ccp.c  */
 585 bool fold_stmt (tree *);
 586 tree widen_bitfield (tree, tree, tree);
 587
 588 /* In tree-ssa-dom.c  */
 589 extern void dump_dominator_optimization_stats (FILE *);
 590 extern void debug_dominator_optimization_stats (void);
 591
 592 /* In tree-ssa-copy.c  */
 593 extern void propagate_value (use_operand_p, tree);
 594 extern void propagate_tree_value (tree *, tree);
 595 extern void replace_exp (use_operand_p, tree);
 596 extern bool may_propagate_copy (tree, tree);
 597
 598 /* Description of number of iterations of a loop.  All the expressions inside
 599    the structure can be evaluated at the end of the loop's preheader
 600    (and due to ssa form, also anywhere inside the body of the loop).  */
 601
 602 struct tree_niter_desc
 603 {
 604   tree assumptions;     /* The boolean expression.  If this expression evalutes
 605                            to false, then the other fields in this structure
 606                            should not be used; there is no guarantee that they
 607                            will be correct.  */
 608   tree may_be_zero;     /* The booleand expression.  If it evaluates to true,
 609                            the loop will exit in the first iteration (i.e.
 610                            its latch will not be executed), even if the niter
 611                            field says otherwise.  */
 612   tree niter;           /* The expression giving the number of iterations of
 613                            a loop (provided that assumptions == true and
 614                            may_be_zero == false), more precisely the number
 615                            of executions of the latch of the loop.  */
 616   tree additional_info; /* The boolean expression.  Sometimes we use additional
 617                            knowledge to simplify the other expressions
 618                            contained in this structure (for example the
 619                            knowledge about value ranges of operands on entry to
 620                            the loop).  If this is a case, conjunction of such
 621                            condition is stored in this field, so that we do not
 622                            lose the information: for example if may_be_zero
 623                            is (n <= 0) and niter is (unsigned) n, we know
 624                            that the number of iterations is at most
 625                            MAX_SIGNED_INT.  However if the (n <= 0) assumption
 626                            is eliminated (by looking at the guard on entry of
 627                            the loop), then the information would be lost.  */
 628 };
 629
 630 /* In tree-ssa-loop*.c  */
 631
 632 void tree_ssa_lim (struct loops *);
 633
 634 void number_of_iterations_cond (tree, tree, tree, enum tree_code, tree, tree,
 635                                 struct tree_niter_desc *);
 636 bool number_of_iterations_exit (struct loop *, edge,
 637                                 struct tree_niter_desc *niter);
 638 tree loop_niter_by_eval (struct loop *, edge);
 639 tree find_loop_niter_by_eval (struct loop *, edge *);
 640 void estimate_numbers_of_iterations (struct loops *);
 641 tree can_count_iv_in_wider_type (struct loop *, tree, tree, tree, tree);
 642 void free_numbers_of_iterations_estimates (struct loops *);
 643 void loop_commit_inserts (void);
 644 bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
 645
 646 /* In tree-flow-inline.h  */
 647 static inline int phi_arg_from_edge (tree, edge);
 648 static inline bool is_call_clobbered (tree);
 649 static inline void mark_call_clobbered (tree);
 650
 651 /* In tree-eh.c  */
 652 extern void make_eh_edges (tree);
 653 extern bool tree_could_trap_p (tree);
 654 extern bool tree_could_throw_p (tree);
 655 extern bool tree_can_throw_internal (tree);
 656 extern bool tree_can_throw_external (tree);
 657 extern int lookup_stmt_eh_region (tree);
 658 extern void add_stmt_to_eh_region (tree, int);
 659 extern bool remove_stmt_from_eh_region (tree);
 660 extern bool maybe_clean_eh_stmt (tree);
 661
 662 /* In tree-ssa-pre.c  */
 663 void add_to_value (tree, tree);
 664 void debug_value_expressions (tree);
 665 void print_value_expressions (FILE *, tree);
 666
 667
 668 /* In tree-vn.c  */
 669 bool expressions_equal_p (tree, tree);
 670 tree get_value_handle (tree);
 671 hashval_t vn_compute (tree, hashval_t, vuse_optype);
 672 tree vn_lookup_or_add (tree, vuse_optype);
 673 void vn_add (tree, tree, vuse_optype);
 674 tree vn_lookup (tree, vuse_optype);
 675 void vn_init (void);
 676 void vn_delete (void);
 677
 678
 679 /* In tree-sra.c  */
 680 void insert_edge_copies (tree stmt, basic_block bb);
 681
 682 #include "tree-flow-inline.h"
 683
 684 #endif /* _TREE_FLOW_H  */