gcc/basic-block.h

   1 /* Define control and data flow tables, and regsets.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 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 the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 #ifndef GCC_BASIC_BLOCK_H
  23 #define GCC_BASIC_BLOCK_H
  24
  25 #include "bitmap.h"
  26 #include "sbitmap.h"
  27 #include "varray.h"
  28 #include "partition.h"
  29 #include "hard-reg-set.h"
  30
  31 /* Head of register set linked list.  */
  32 typedef bitmap_head regset_head;
  33 /* A pointer to a regset_head.  */
  34 typedef bitmap regset;
  35
  36 /* Initialize a new regset.  */
  37 #define INIT_REG_SET(HEAD) bitmap_initialize (HEAD, 1)
  38
  39 /* Clear a register set by freeing up the linked list.  */
  40 #define CLEAR_REG_SET(HEAD) bitmap_clear (HEAD)
  41
  42 /* Copy a register set to another register set.  */
  43 #define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
  44
  45 /* Compare two register sets.  */
  46 #define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
  47
  48 /* `and' a register set with a second register set.  */
  49 #define AND_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_AND)
  50
  51 /* `and' the complement of a register set with a register set.  */
  52 #define AND_COMPL_REG_SET(TO, FROM) \
  53   bitmap_operation (TO, TO, FROM, BITMAP_AND_COMPL)
  54
  55 /* Inclusive or a register set with a second register set.  */
  56 #define IOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_IOR)
  57
  58 /* Exclusive or a register set with a second register set.  */
  59 #define XOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_XOR)
  60
  61 /* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
  62 #define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
  63   bitmap_ior_and_compl (TO, FROM1, FROM2)
  64
  65 /* Clear a single register in a register set.  */
  66 #define CLEAR_REGNO_REG_SET(HEAD, REG) bitmap_clear_bit (HEAD, REG)
  67
  68 /* Set a single register in a register set.  */
  69 #define SET_REGNO_REG_SET(HEAD, REG) bitmap_set_bit (HEAD, REG)
  70
  71 /* Return true if a register is set in a register set.  */
  72 #define REGNO_REG_SET_P(TO, REG) bitmap_bit_p (TO, REG)
  73
  74 /* Copy the hard registers in a register set to the hard register set.  */
  75 extern void reg_set_to_hard_reg_set (HARD_REG_SET *, bitmap);
  76 #define REG_SET_TO_HARD_REG_SET(TO, FROM)                               \
  77 do {                                                                    \
  78   CLEAR_HARD_REG_SET (TO);                                              \
  79   reg_set_to_hard_reg_set (&TO, FROM);                                  \
  80 } while (0)
  81
  82 /* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
  83    register number and executing CODE for all registers that are set.  */
  84 #define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, CODE)            \
  85   EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, CODE)
  86
  87 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  88    REGNUM to the register number and executing CODE for all registers that are
  89    set in the first regset and not set in the second.  */
  90 #define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  91   EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  92
  93 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  94    REGNUM to the register number and executing CODE for all registers that are
  95    set in both regsets.  */
  96 #define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  97   EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  98
  99 /* Allocate a register set with oballoc.  */
 100 #define OBSTACK_ALLOC_REG_SET(OBSTACK) BITMAP_OBSTACK_ALLOC (OBSTACK)
 101
 102 /* Initialize a register set.  Returns the new register set.  */
 103 #define INITIALIZE_REG_SET(HEAD) bitmap_initialize (&HEAD, 1)
 104
 105 /* Do any cleanup needed on a regset when it is no longer used.  */
 106 #define FREE_REG_SET(REGSET) BITMAP_FREE(REGSET)
 107
 108 /* Do any one-time initializations needed for regsets.  */
 109 #define INIT_ONCE_REG_SET() BITMAP_INIT_ONCE ()
 110
 111 /* Grow any tables needed when the number of registers is calculated
 112    or extended.  For the linked list allocation, nothing needs to
 113    be done, other than zero the statistics on the first allocation.  */
 114 #define MAX_REGNO_REG_SET(NUM_REGS, NEW_P, RENUMBER_P)
 115
 116 /* Type we use to hold basic block counters.  Should be at least
 117    64bit.  Although a counter cannot be negative, we use a signed
 118    type, because erroneous negative counts can be generated when the
 119    flow graph is manipulated by various optimizations.  A signed type
 120    makes those easy to detect.  */
 121 typedef HOST_WIDEST_INT gcov_type;
 122
 123 /* Control flow edge information.  */
 124 typedef struct edge_def {
 125   /* Links through the predecessor and successor lists.  */
 126   struct edge_def *pred_next, *succ_next;
 127
 128   /* The two blocks at the ends of the edge.  */
 129   struct basic_block_def *src, *dest;
 130
 131   /* Instructions queued on the edge.  */
 132   rtx insns;
 133
 134   /* Auxiliary info specific to a pass.  */
 135   void *aux;
 136
 137   int flags;                    /* see EDGE_* below  */
 138   int probability;              /* biased by REG_BR_PROB_BASE */
 139   gcov_type count;              /* Expected number of executions calculated
 140                                    in profile.c  */
 141 } *edge;
 142
 143 #define EDGE_FALLTHRU           1       /* 'Straight line' flow */
 144 #define EDGE_ABNORMAL           2       /* Strange flow, like computed
 145                                            label, or eh */
 146 #define EDGE_ABNORMAL_CALL      4       /* Call with abnormal exit
 147                                            like an exception, or sibcall */
 148 #define EDGE_EH                 8       /* Exception throw */
 149 #define EDGE_FAKE               16      /* Not a real edge (profile.c) */
 150 #define EDGE_DFS_BACK           32      /* A backwards edge */
 151 #define EDGE_CAN_FALLTHRU       64      /* Candidate for straight line
 152                                            flow.  */
 153 #define EDGE_IRREDUCIBLE_LOOP   128     /* Part of irreducible loop.  */
 154 #define EDGE_SIBCALL            256     /* Edge from sibcall to exit.  */
 155 #define EDGE_LOOP_EXIT          512     /* Exit of a loop.  */
 156 #define EDGE_TRUE_VALUE         1024    /* Edge taken when controlling
 157                                            predicate is non zero.  */
 158 #define EDGE_FALSE_VALUE        2048    /* Edge taken when controlling
 159                                            predicate is zero.  */
 160 #define EDGE_EXECUTABLE         4096    /* Edge is executable.  Only
 161                                            valid during SSA-CCP.  */
 162 #define EDGE_ALL_FLAGS          8191
 163
 164 #define EDGE_COMPLEX    (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
 165
 166 /* Counter summary from the last set of coverage counts read by
 167    profile.c.  */
 168 extern const struct gcov_ctr_summary *profile_info;
 169
 170 /* Declared in cfgloop.h.  */
 171 struct loop;
 172 struct loops;
 173
 174 /* Declared in tree-flow.h.  */
 175 struct bb_ann_d;
 176
 177 /* A basic block is a sequence of instructions with only entry and
 178    only one exit.  If any one of the instructions are executed, they
 179    will all be executed, and in sequence from first to last.
 180
 181    There may be COND_EXEC instructions in the basic block.  The
 182    COND_EXEC *instructions* will be executed -- but if the condition
 183    is false the conditionally executed *expressions* will of course
 184    not be executed.  We don't consider the conditionally executed
 185    expression (which might have side-effects) to be in a separate
 186    basic block because the program counter will always be at the same
 187    location after the COND_EXEC instruction, regardless of whether the
 188    condition is true or not.
 189
 190    Basic blocks need not start with a label nor end with a jump insn.
 191    For example, a previous basic block may just "conditionally fall"
 192    into the succeeding basic block, and the last basic block need not
 193    end with a jump insn.  Block 0 is a descendant of the entry block.
 194
 195    A basic block beginning with two labels cannot have notes between
 196    the labels.
 197
 198    Data for jump tables are stored in jump_insns that occur in no
 199    basic block even though these insns can follow or precede insns in
 200    basic blocks.  */
 201
 202 /* Basic block information indexed by block number.  */
 203 struct basic_block_def GTY((fields_only ("")))
 204 {
 205   /* The first and last insns of the block.  */
 206   rtx head;
 207   rtx end;
 208
 209   /* The first and last trees of the block.  */
 210   struct tree_container *head_tree;
 211   struct tree_container *end_tree;
 212
 213   /* The edges into and out of the block.  */
 214   struct edge_def * GTY((skip (""))) pred;
 215   struct edge_def * GTY((skip (""))) succ;
 216
 217   /* Liveness info.  */
 218
 219   /* The registers that are modified within this in block.  */
 220   bitmap GTY((skip (""))) local_set;
 221   /* The registers that are conditionally modified within this block.
 222      In other words, registers that are set only as part of a
 223      COND_EXEC.  */
 224   bitmap GTY((skip (""))) cond_local_set;
 225   /* The registers that are live on entry to this block.
 226
 227      Note that in SSA form, global_live_at_start does not reflect the
 228      use of regs in phi functions, since the liveness of these regs
 229      may depend on which edge was taken into the block.  */
 230   bitmap GTY((skip (""))) global_live_at_start;
 231   /* The registers that are live on exit from this block.  */
 232   bitmap GTY((skip (""))) global_live_at_end;
 233
 234   /* Auxiliary info specific to a pass.  */
 235   PTR GTY((skip (""))) aux;
 236
 237   /* The index of this block.  */
 238   int index;
 239
 240   /* Previous and next blocks in the chain.  The GTY((skip (""))) is necessary,
 241      since the basic blocks themselves are not marked and we would cause a quadratic
 242      behavior otherwise.  */
 243   struct basic_block_def * GTY((skip (""))) prev_bb;
 244   struct basic_block_def * GTY((skip (""))) next_bb;
 245
 246   /* The loop depth of this block.  */
 247   int loop_depth;
 248
 249   /* Innermost loop containing the block.  */
 250   struct loop * GTY((skip (""))) loop_father;
 251
 252   /* Expected number of executions: calculated in profile.c.  */
 253   gcov_type count;
 254
 255   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 256   int frequency;
 257
 258   /* Various flags.  See BB_* below.  */
 259   int flags;
 260
 261   /* Additional data maintained by cfg_layout routines.  */
 262   struct reorder_block_def * GTY((skip (""))) rbi;
 263
 264   /* Annotations used at the tree level.  */
 265   struct bb_ann_d *tree_annotations;
 266 };
 267
 268 typedef struct basic_block_def *basic_block;
 269
 270 #define BB_FREQ_MAX 10000
 271
 272 /* Masks for basic_block.flags.  */
 273 #define BB_DIRTY                1
 274 #define BB_NEW                  2
 275 #define BB_REACHABLE            4
 276 #define BB_VISITED              8
 277 #define BB_IRREDUCIBLE_LOOP     16
 278 #define BB_SUPERBLOCK           32
 279
 280 /* Number of basic blocks in the current function.  */
 281
 282 extern int n_basic_blocks;
 283
 284 /* First free basic block number.  */
 285
 286 extern int last_basic_block;
 287
 288 /* Number of edges in the current function.  */
 289
 290 extern int n_edges;
 291
 292 /* Index by basic block number, get basic block struct info.  */
 293
 294 extern GTY(()) varray_type basic_block_info;
 295
 296 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 297
 298 /* For iterating over basic blocks.  */
 299 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 300   for (BB = FROM; BB != TO; BB = BB->DIR)
 301
 302 #define FOR_EACH_BB(BB) \
 303   FOR_BB_BETWEEN (BB, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR, next_bb)
 304
 305 #define FOR_EACH_BB_REVERSE(BB) \
 306   FOR_BB_BETWEEN (BB, EXIT_BLOCK_PTR->prev_bb, ENTRY_BLOCK_PTR, prev_bb)
 307
 308 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 309    exit block).  */
 310
 311 #define FOR_ALL_BB(BB) \
 312   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 313
 314 /* What registers are live at the setjmp call.  */
 315
 316 extern regset regs_live_at_setjmp;
 317
 318 /* Special labels found during CFG build.  */
 319
 320 extern GTY(()) rtx label_value_list;
 321 extern GTY(()) rtx tail_recursion_label_list;
 322
 323 extern struct obstack flow_obstack;
 324
 325 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 326    If the value is REG_BLOCK_GLOBAL (-2),
 327    it means (REG n) is used in more than one basic block.
 328    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 329    This information remains valid for the rest of the compilation
 330    of the current function; it is used to control register allocation.  */
 331
 332 #define REG_BLOCK_UNKNOWN -1
 333 #define REG_BLOCK_GLOBAL -2
 334
 335 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 336 \f
 337 /* Stuff for recording basic block info.  */
 338
 339 #define BLOCK_HEAD(B)      (BASIC_BLOCK (B)->head)
 340 #define BLOCK_END(B)       (BASIC_BLOCK (B)->end)
 341
 342 /* Special block numbers [markers] for entry and exit.  */
 343 #define ENTRY_BLOCK (-1)
 344 #define EXIT_BLOCK (-2)
 345
 346 /* Special block number not valid for any block.  */
 347 #define INVALID_BLOCK (-3)
 348
 349 /* Similarly, block pointers for the edge list.  */
 350 extern struct basic_block_def entry_exit_blocks[2];
 351 #define ENTRY_BLOCK_PTR (&entry_exit_blocks[0])
 352 #define EXIT_BLOCK_PTR  (&entry_exit_blocks[1])
 353
 354 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 355 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 356
 357 extern void compute_bb_for_insn (void);
 358 extern void free_bb_for_insn (void);
 359 extern void update_bb_for_insn (basic_block);
 360
 361 extern void free_basic_block_vars (int);
 362
 363 extern void insert_insn_on_edge (rtx, edge);
 364 bool safe_insert_insn_on_edge (rtx, edge);
 365
 366 extern void commit_edge_insertions (void);
 367 extern void commit_edge_insertions_watch_calls (void);
 368
 369 extern void remove_fake_edges (void);
 370 extern void add_noreturn_fake_exit_edges (void);
 371 extern void connect_infinite_loops_to_exit (void);
 372 extern int flow_call_edges_add (sbitmap);
 373 extern edge unchecked_make_edge (basic_block, basic_block, int);
 374 extern edge cached_make_edge (sbitmap *, basic_block, basic_block, int);
 375 extern edge make_edge (basic_block, basic_block, int);
 376 extern edge make_single_succ_edge (basic_block, basic_block, int);
 377 extern void remove_edge (edge);
 378 extern void redirect_edge_succ (edge, basic_block);
 379 extern edge redirect_edge_succ_nodup (edge, basic_block);
 380 extern void redirect_edge_pred (edge, basic_block);
 381 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 382 extern void clear_bb_flags (void);
 383 extern void tidy_fallthru_edge (edge, basic_block, basic_block);
 384 extern void flow_reverse_top_sort_order_compute (int *);
 385 extern int flow_depth_first_order_compute (int *, int *);
 386 extern void flow_preorder_transversal_compute (int *);
 387 extern int dfs_enumerate_from (basic_block, int,
 388                                bool (*)(basic_block, void *),
 389                                basic_block *, int, void *);
 390 extern void dump_edge_info (FILE *, edge, int);
 391 extern void clear_edges (void);
 392 extern void mark_critical_edges (void);
 393 extern rtx first_insn_after_basic_block_note (basic_block);
 394 extern basic_block create_bb (void);
 395
 396 /* Dominator information for basic blocks.  */
 397
 398 typedef struct dominance_info *dominance_info;
 399
 400 /* Structure to group all of the information to process IF-THEN and
 401    IF-THEN-ELSE blocks for the conditional execution support.  This
 402    needs to be in a public file in case the IFCVT macros call
 403    functions passing the ce_if_block data structure.  */
 404
 405 typedef struct ce_if_block
 406 {
 407   basic_block test_bb;                  /* First test block.  */
 408   basic_block then_bb;                  /* THEN block.  */
 409   basic_block else_bb;                  /* ELSE block or NULL.  */
 410   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 411   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 412   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 413   int num_and_and_blocks;               /* # of && blocks.  */
 414   int num_or_or_blocks;                 /* # of || blocks.  */
 415   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 416   int and_and_p;                        /* Complex test is &&.  */
 417   int num_then_insns;                   /* # of insns in THEN block.  */
 418   int num_else_insns;                   /* # of insns in ELSE block.  */
 419   int pass;                             /* Pass number.  */
 420
 421 #ifdef IFCVT_EXTRA_FIELDS
 422   IFCVT_EXTRA_FIELDS                    /* Any machine dependent fields.  */
 423 #endif
 424
 425 } ce_if_block_t;
 426
 427 /* This structure maintains an edge list vector.  */
 428 struct edge_list
 429 {
 430   int num_blocks;
 431   int num_edges;
 432   edge *index_to_edge;
 433 };
 434
 435 /* This is the value which indicates no edge is present.  */
 436 #define EDGE_INDEX_NO_EDGE      -1
 437
 438 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 439    if there is no edge between the 2 basic blocks.  */
 440 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 441
 442 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 443    block which is either the pred or succ end of the indexed edge.  */
 444 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 445 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 446
 447 /* INDEX_EDGE returns a pointer to the edge.  */
 448 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 449
 450 /* Number of edges in the compressed edge list.  */
 451 #define NUM_EDGES(el)                   ((el)->num_edges)
 452
 453 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 454 #define FALLTHRU_EDGE(bb)               ((bb)->succ->flags & EDGE_FALLTHRU \
 455                                          ? (bb)->succ : (bb)->succ->succ_next)
 456
 457 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 458 #define BRANCH_EDGE(bb)                 ((bb)->succ->flags & EDGE_FALLTHRU \
 459                                          ? (bb)->succ->succ_next : (bb)->succ)
 460
 461 /* Return expected execution frequency of the edge E.  */
 462 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 463                                           * (e)->probability \
 464                                           + REG_BR_PROB_BASE / 2) \
 465                                          / REG_BR_PROB_BASE)
 466
 467 /* Return nonzero if edge is critical.  */
 468 #define EDGE_CRITICAL_P(e)              ((e)->src->succ->succ_next \
 469                                          && (e)->dest->pred->pred_next)
 470
 471 struct edge_list * create_edge_list (void);
 472 void free_edge_list (struct edge_list *);
 473 void print_edge_list (FILE *, struct edge_list *);
 474 void verify_edge_list (FILE *, struct edge_list *);
 475 int find_edge_index (struct edge_list *, basic_block, basic_block);
 476 edge find_edge (basic_block, basic_block);
 477
 478
 479 enum update_life_extent
 480 {
 481   UPDATE_LIFE_LOCAL = 0,
 482   UPDATE_LIFE_GLOBAL = 1,
 483   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 484 };
 485
 486 /* Flags for life_analysis and update_life_info.  */
 487
 488 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 489 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 490 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 491 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 492 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 493 #define PROP_ALLOW_CFG_CHANGES  32      /* Allow the CFG to be changed
 494                                            by dead code removal.  */
 495 #define PROP_AUTOINC            64      /* Create autoinc mem references.  */
 496 #define PROP_EQUAL_NOTES        128     /* Take into account REG_EQUAL notes.  */
 497 #define PROP_SCAN_DEAD_STORES   256     /* Scan for dead code.  */
 498 #define PROP_FINAL              (PROP_DEATH_NOTES | PROP_LOG_LINKS  \
 499                                  | PROP_REG_INFO | PROP_KILL_DEAD_CODE  \
 500                                  | PROP_SCAN_DEAD_CODE | PROP_AUTOINC \
 501                                  | PROP_ALLOW_CFG_CHANGES \
 502                                  | PROP_SCAN_DEAD_STORES)
 503
 504 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 505                                            except for edge forwarding */
 506 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 507 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 508                                            to care REG_DEAD notes.  */
 509 #define CLEANUP_PRE_SIBCALL     8       /* Do not get confused by code hidden
 510                                            inside call_placeholders..  */
 511 #define CLEANUP_PRE_LOOP        16      /* Take care to preserve syntactic loop
 512                                            notes.  */
 513 #define CLEANUP_UPDATE_LIFE     32      /* Keep life information up to date.  */
 514 #define CLEANUP_THREADING       64      /* Do jump threading.  */
 515 #define CLEANUP_NO_INSN_DEL     128     /* Do not try to delete trivially dead
 516                                            insns.  */
 517 #define CLEANUP_CFGLAYOUT       256     /* Do cleanup in cfglayout mode.  */
 518 extern void life_analysis (rtx, FILE *, int);
 519 extern int update_life_info (sbitmap, enum update_life_extent, int);
 520 extern int update_life_info_in_dirty_blocks (enum update_life_extent, int);
 521 extern int count_or_remove_death_notes (sbitmap, int);
 522 extern int propagate_block (basic_block, regset, regset, regset, int);
 523
 524 struct propagate_block_info;
 525 extern rtx propagate_one_insn (struct propagate_block_info *, rtx);
 526 extern struct propagate_block_info *init_propagate_block_info
 527  (basic_block, regset, regset, regset, int);
 528 extern void free_propagate_block_info (struct propagate_block_info *);
 529
 530 /* In lcm.c */
 531 extern struct edge_list *pre_edge_lcm (FILE *, int, sbitmap *, sbitmap *,
 532                                        sbitmap *, sbitmap *, sbitmap **,
 533                                        sbitmap **);
 534 extern struct edge_list *pre_edge_rev_lcm (FILE *, int, sbitmap *,
 535                                            sbitmap *, sbitmap *,
 536                                            sbitmap *, sbitmap **,
 537                                            sbitmap **);
 538 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 539 extern int optimize_mode_switching (FILE *);
 540
 541 /* In emit-rtl.c.  */
 542 extern rtx emit_block_insn_after (rtx, rtx, basic_block);
 543 extern rtx emit_block_insn_before (rtx, rtx, basic_block);
 544
 545 /* In predict.c */
 546 extern void estimate_probability (struct loops *);
 547 extern void note_prediction_to_br_prob (void);
 548 extern void expected_value_to_br_prob (void);
 549 extern bool maybe_hot_bb_p (basic_block);
 550 extern bool probably_cold_bb_p (basic_block);
 551 extern bool probably_never_executed_bb_p (basic_block);
 552
 553 /* In flow.c */
 554 extern void init_flow (void);
 555 extern void dump_bb (basic_block, FILE *);
 556 extern void debug_bb (basic_block);
 557 extern void dump_cfg (void);
 558 extern basic_block debug_bb_n (int);
 559 extern void dump_regset (regset, FILE *);
 560 extern void debug_regset (regset);
 561 extern void allocate_reg_life_data (void);
 562 extern void allocate_bb_life_data (void);
 563 extern void expunge_block (basic_block);
 564 extern void link_block (basic_block, basic_block);
 565 extern void unlink_block (basic_block);
 566 extern void compact_blocks (void);
 567 extern basic_block alloc_block (void);
 568 extern void find_unreachable_blocks (void);
 569 extern int delete_noop_moves (rtx);
 570 extern basic_block force_nonfallthru (edge);
 571 extern rtx block_label (basic_block);
 572 extern bool forwarder_block_p (basic_block);
 573 extern bool purge_all_dead_edges (int);
 574 extern bool purge_dead_edges (basic_block);
 575 extern void find_sub_basic_blocks (basic_block);
 576 extern void find_many_sub_basic_blocks (sbitmap);
 577 extern bool can_fallthru (basic_block, basic_block);
 578 extern void flow_nodes_print (const char *, const sbitmap, FILE *);
 579 extern void flow_edge_list_print (const char *, const edge *, int, FILE *);
 580 extern void alloc_aux_for_block (basic_block, int);
 581 extern void alloc_aux_for_blocks (int);
 582 extern void clear_aux_for_blocks (void);
 583 extern void free_aux_for_blocks (void);
 584 extern void alloc_aux_for_edge (edge, int);
 585 extern void alloc_aux_for_edges (int);
 586 extern void clear_aux_for_edges (void);
 587 extern void free_aux_for_edges (void);
 588
 589 /* This function is always defined so it can be called from the
 590    debugger, and it is declared extern so we don't get warnings about
 591    it being unused.  */
 592 extern void verify_flow_info (void);
 593
 594 typedef struct conflict_graph_def *conflict_graph;
 595
 596 /* Callback function when enumerating conflicts.  The arguments are
 597    the smaller and larger regno in the conflict.  Returns zero if
 598    enumeration is to continue, nonzero to halt enumeration.  */
 599 typedef int (*conflict_graph_enum_fn) (int, int, void *);
 600
 601
 602 /* Prototypes of operations on conflict graphs.  */
 603
 604 extern conflict_graph conflict_graph_new
 605  (int);
 606 extern void conflict_graph_delete (conflict_graph);
 607 extern int conflict_graph_add (conflict_graph, int, int);
 608 extern int conflict_graph_conflict_p (conflict_graph, int, int);
 609 extern void conflict_graph_enum (conflict_graph, int, conflict_graph_enum_fn,
 610                                  void *);
 611 extern void conflict_graph_merge_regs (conflict_graph, int, int);
 612 extern void conflict_graph_print (conflict_graph, FILE*);
 613 extern conflict_graph conflict_graph_compute (regset, partition);
 614 extern bool mark_dfs_back_edges (void);
 615 extern void set_edge_can_fallthru_flag (void);
 616 extern void update_br_prob_note (basic_block);
 617 extern void fixup_abnormal_edges (void);
 618 extern bool can_hoist_insn_p (rtx, rtx, regset);
 619 extern rtx hoist_insn_after (rtx, rtx, rtx, rtx);
 620 extern rtx hoist_insn_to_edge (rtx, edge, rtx, rtx);
 621 extern bool inside_basic_block_p (rtx);
 622 extern bool control_flow_insn_p (rtx);
 623
 624 /* In bb-reorder.c */
 625 extern void reorder_basic_blocks (void);
 626
 627 /* In dominance.c */
 628
 629 enum cdi_direction
 630 {
 631   CDI_DOMINATORS,
 632   CDI_POST_DOMINATORS
 633 };
 634
 635 extern dominance_info calculate_dominance_info (enum cdi_direction);
 636 extern void free_dominance_info (dominance_info);
 637 extern basic_block nearest_common_dominator (dominance_info,
 638                                              basic_block, basic_block);
 639 extern void set_immediate_dominator (dominance_info, basic_block,
 640                                      basic_block);
 641 extern basic_block get_immediate_dominator (dominance_info, basic_block);
 642 extern bool dominated_by_p (dominance_info, basic_block, basic_block);
 643 extern int get_dominated_by (dominance_info, basic_block, basic_block **);
 644 extern void add_to_dominance_info (dominance_info, basic_block);
 645 extern void delete_from_dominance_info (dominance_info, basic_block);
 646 basic_block recount_dominator (dominance_info, basic_block);
 647 extern void redirect_immediate_dominators (dominance_info, basic_block,
 648                                            basic_block);
 649 void iterate_fix_dominators (dominance_info, basic_block *, int);
 650 extern void verify_dominators (dominance_info);
 651
 652 #include "cfghooks.h"
 653
 654 #endif /* GCC_BASIC_BLOCK_H */