gcc/basic-block.h

   1 /* Define control and data flow tables, and regsets.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   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 #include "predict.h"
  31 #include "vec.h"
  32 #include "errors.h"
  33
  34 /* Head of register set linked list.  */
  35 typedef bitmap_head regset_head;
  36
  37 /* A pointer to a regset_head.  */
  38 typedef bitmap regset;
  39
  40 /* Allocate a register set with oballoc.  */
  41 #define ALLOC_REG_SET(OBSTACK) BITMAP_ALLOC (OBSTACK)
  42
  43 /* Do any cleanup needed on a regset when it is no longer used.  */
  44 #define FREE_REG_SET(REGSET) BITMAP_FREE (REGSET)
  45
  46 /* Initialize a new regset.  */
  47 #define INIT_REG_SET(HEAD) bitmap_initialize (HEAD, &reg_obstack)
  48
  49 /* Clear a register set by freeing up the linked list.  */
  50 #define CLEAR_REG_SET(HEAD) bitmap_clear (HEAD)
  51
  52 /* Copy a register set to another register set.  */
  53 #define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
  54
  55 /* Compare two register sets.  */
  56 #define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
  57
  58 /* `and' a register set with a second register set.  */
  59 #define AND_REG_SET(TO, FROM) bitmap_and_into (TO, FROM)
  60
  61 /* `and' the complement of a register set with a register set.  */
  62 #define AND_COMPL_REG_SET(TO, FROM) bitmap_and_compl_into (TO, FROM)
  63
  64 /* Inclusive or a register set with a second register set.  */
  65 #define IOR_REG_SET(TO, FROM) bitmap_ior_into (TO, FROM)
  66
  67 /* Exclusive or a register set with a second register set.  */
  68 #define XOR_REG_SET(TO, FROM) bitmap_xor_into (TO, FROM)
  69
  70 /* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
  71 #define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
  72   bitmap_ior_and_compl_into (TO, FROM1, FROM2)
  73
  74 /* Clear a single register in a register set.  */
  75 #define CLEAR_REGNO_REG_SET(HEAD, REG) bitmap_clear_bit (HEAD, REG)
  76
  77 /* Set a single register in a register set.  */
  78 #define SET_REGNO_REG_SET(HEAD, REG) bitmap_set_bit (HEAD, REG)
  79
  80 /* Return true if a register is set in a register set.  */
  81 #define REGNO_REG_SET_P(TO, REG) bitmap_bit_p (TO, REG)
  82
  83 /* Copy the hard registers in a register set to the hard register set.  */
  84 extern void reg_set_to_hard_reg_set (HARD_REG_SET *, bitmap);
  85 #define REG_SET_TO_HARD_REG_SET(TO, FROM)                               \
  86 do {                                                                    \
  87   CLEAR_HARD_REG_SET (TO);                                              \
  88   reg_set_to_hard_reg_set (&TO, FROM);                                  \
  89 } while (0)
  90
  91 typedef bitmap_iterator reg_set_iterator;
  92
  93 /* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
  94    register number and executing CODE for all registers that are set.  */
  95 #define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, RSI)     \
  96   EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, RSI)
  97
  98 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  99    REGNUM to the register number and executing CODE for all registers that are
 100    set in the first regset and not set in the second.  */
 101 #define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, RSI) \
 102   EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, RSI)
 103
 104 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
 105    REGNUM to the register number and executing CODE for all registers that are
 106    set in both regsets.  */
 107 #define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, RSI) \
 108   EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, RSI) \
 109
 110 /* Type we use to hold basic block counters.  Should be at least
 111    64bit.  Although a counter cannot be negative, we use a signed
 112    type, because erroneous negative counts can be generated when the
 113    flow graph is manipulated by various optimizations.  A signed type
 114    makes those easy to detect.  */
 115 typedef HOST_WIDEST_INT gcov_type;
 116
 117 /* Control flow edge information.  */
 118 struct edge_def GTY(())
 119 {
 120   /* The two blocks at the ends of the edge.  */
 121   struct basic_block_def *src;
 122   struct basic_block_def *dest;
 123
 124   /* Instructions queued on the edge.  */
 125   union edge_def_insns {
 126     rtx GTY ((tag ("0"))) r;
 127     tree GTY ((tag ("1"))) t;
 128   } GTY ((desc ("ir_type ()"))) insns;
 129
 130   /* Auxiliary info specific to a pass.  */
 131   PTR GTY ((skip (""))) aux;
 132
 133   /* Location of any goto implicit in the edge, during tree-ssa.  */
 134   source_locus goto_locus;
 135
 136   int flags;                    /* see EDGE_* below  */
 137   int probability;              /* biased by REG_BR_PROB_BASE */
 138   gcov_type count;              /* Expected number of executions calculated
 139                                    in profile.c  */
 140
 141   /* The index number corresponding to this edge in the edge vector
 142      dest->preds.  */
 143   unsigned int dest_idx;
 144 };
 145
 146 typedef struct edge_def *edge;
 147 DEF_VEC_GC_P(edge);
 148
 149 #define EDGE_FALLTHRU           1       /* 'Straight line' flow */
 150 #define EDGE_ABNORMAL           2       /* Strange flow, like computed
 151                                            label, or eh */
 152 #define EDGE_ABNORMAL_CALL      4       /* Call with abnormal exit
 153                                            like an exception, or sibcall */
 154 #define EDGE_EH                 8       /* Exception throw */
 155 #define EDGE_FAKE               16      /* Not a real edge (profile.c) */
 156 #define EDGE_DFS_BACK           32      /* A backwards edge */
 157 #define EDGE_CAN_FALLTHRU       64      /* Candidate for straight line
 158                                            flow.  */
 159 #define EDGE_IRREDUCIBLE_LOOP   128     /* Part of irreducible loop.  */
 160 #define EDGE_SIBCALL            256     /* Edge from sibcall to exit.  */
 161 #define EDGE_LOOP_EXIT          512     /* Exit of a loop.  */
 162 #define EDGE_TRUE_VALUE         1024    /* Edge taken when controlling
 163                                            predicate is nonzero.  */
 164 #define EDGE_FALSE_VALUE        2048    /* Edge taken when controlling
 165                                            predicate is zero.  */
 166 #define EDGE_EXECUTABLE         4096    /* Edge is executable.  Only
 167                                            valid during SSA-CCP.  */
 168 #define EDGE_CROSSING           8192    /* Edge crosses between hot
 169                                            and cold sections, when we
 170                                            do partitioning.  */
 171 #define EDGE_ALL_FLAGS         16383
 172
 173 #define EDGE_COMPLEX    (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
 174
 175 /* Counter summary from the last set of coverage counts read by
 176    profile.c.  */
 177 extern const struct gcov_ctr_summary *profile_info;
 178
 179 /* Declared in cfgloop.h.  */
 180 struct loop;
 181 struct loops;
 182
 183 /* Declared in tree-flow.h.  */
 184 struct bb_ann_d;
 185
 186 /* A basic block is a sequence of instructions with only entry and
 187    only one exit.  If any one of the instructions are executed, they
 188    will all be executed, and in sequence from first to last.
 189
 190    There may be COND_EXEC instructions in the basic block.  The
 191    COND_EXEC *instructions* will be executed -- but if the condition
 192    is false the conditionally executed *expressions* will of course
 193    not be executed.  We don't consider the conditionally executed
 194    expression (which might have side-effects) to be in a separate
 195    basic block because the program counter will always be at the same
 196    location after the COND_EXEC instruction, regardless of whether the
 197    condition is true or not.
 198
 199    Basic blocks need not start with a label nor end with a jump insn.
 200    For example, a previous basic block may just "conditionally fall"
 201    into the succeeding basic block, and the last basic block need not
 202    end with a jump insn.  Block 0 is a descendant of the entry block.
 203
 204    A basic block beginning with two labels cannot have notes between
 205    the labels.
 206
 207    Data for jump tables are stored in jump_insns that occur in no
 208    basic block even though these insns can follow or precede insns in
 209    basic blocks.  */
 210
 211 /* Basic block information indexed by block number.  */
 212 struct basic_block_def GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb")))
 213 {
 214   /* The first and last insns of the block.  */
 215   rtx head_;
 216   rtx end_;
 217
 218   /* Pointers to the first and last trees of the block.  */
 219   tree stmt_list;
 220
 221   /* The edges into and out of the block.  */
 222   VEC(edge) *preds;
 223   VEC(edge) *succs;
 224
 225   /* The registers that are live on entry to this block.  */
 226   bitmap GTY ((skip (""))) global_live_at_start;
 227
 228   /* The registers that are live on exit from this block.  */
 229   bitmap GTY ((skip (""))) global_live_at_end;
 230
 231   /* Auxiliary info specific to a pass.  */
 232   PTR GTY ((skip (""))) aux;
 233
 234   /* Innermost loop containing the block.  */
 235   struct loop * GTY ((skip (""))) loop_father;
 236
 237   /* The dominance and postdominance information node.  */
 238   struct et_node * GTY ((skip (""))) dom[2];
 239
 240   /* Previous and next blocks in the chain.  */
 241   struct basic_block_def *prev_bb;
 242   struct basic_block_def *next_bb;
 243
 244   /* The data used by basic block copying and reordering functions.  */
 245   struct reorder_block_def * GTY ((skip (""))) rbi;
 246
 247   /* Annotations used at the tree level.  */
 248   struct bb_ann_d *tree_annotations;
 249
 250   /* Expected number of executions: calculated in profile.c.  */
 251   gcov_type count;
 252
 253   /* The index of this block.  */
 254   int index;
 255
 256   /* The loop depth of this block.  */
 257   int loop_depth;
 258
 259   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 260   int frequency;
 261
 262   /* Various flags.  See BB_* below.  */
 263   int flags;
 264 };
 265
 266 typedef struct basic_block_def *basic_block;
 267
 268 /* Structure to hold information about the blocks during reordering and
 269    copying.  */
 270
 271 typedef struct reorder_block_def
 272 {
 273   rtx header;
 274   rtx footer;
 275   basic_block next;
 276   basic_block original;
 277   /* Used by loop copying.  */
 278   basic_block copy;
 279   int duplicated;
 280   int copy_number;
 281
 282   /* These fields are used by bb-reorder pass.  */
 283   int visited;
 284 } *reorder_block_def_p;
 285
 286 #define BB_FREQ_MAX 10000
 287
 288 /* Masks for basic_block.flags.
 289
 290    BB_HOT_PARTITION and BB_COLD_PARTITION should be preserved throughout
 291    the compilation, so they are never cleared.
 292
 293    All other flags may be cleared by clear_bb_flags().  It is generally
 294    a bad idea to rely on any flags being up-to-date.  */
 295
 296 enum
 297 {
 298
 299   /* Set if insns in BB have are modified.  Used for updating liveness info.  */
 300   BB_DIRTY = 1,
 301
 302   /* Only set on blocks that have just been created by create_bb.  */
 303   BB_NEW = 2,
 304
 305   /* Set by find_unreachable_blocks.  Do not rely on this being set in any
 306      pass.  */
 307   BB_REACHABLE = 4,
 308
 309   /* Set for blocks in an irreducible loop by loop analysis.  */
 310   BB_IRREDUCIBLE_LOOP = 8,
 311
 312   /* Set on blocks that may actually not be single-entry single-exit block.  */
 313   BB_SUPERBLOCK = 16,
 314
 315   /* Set on basic blocks that the scheduler should not touch.  This is used
 316      by SMS to prevent other schedulers from messing with the loop schedule.  */
 317   BB_DISABLE_SCHEDULE = 32,
 318
 319   /* Set on blocks that should be put in a hot section.  */
 320   BB_HOT_PARTITION = 64,
 321
 322   /* Set on blocks that should be put in a cold section.  */
 323   BB_COLD_PARTITION = 128
 324 };
 325
 326 /* Dummy flag for convenience in the hot/cold partitioning code.  */
 327 #define BB_UNPARTITIONED        0
 328
 329 /* Partitions, to be used when partitioning hot and cold basic blocks into
 330    separate sections.  */
 331 #define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))
 332 #define BB_SET_PARTITION(bb, part) do {                                 \
 333   basic_block bb_ = (bb);                                               \
 334   bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \
 335                 | (part));                                              \
 336 } while (0)
 337
 338 #define BB_COPY_PARTITION(dstbb, srcbb) \
 339   BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))
 340
 341 /* Number of basic blocks in the current function.  */
 342
 343 extern int n_basic_blocks;
 344
 345 /* First free basic block number.  */
 346
 347 extern int last_basic_block;
 348
 349 /* Number of edges in the current function.  */
 350
 351 extern int n_edges;
 352
 353 /* TRUE if we should re-run loop discovery after threading jumps, FALSE
 354    otherwise.  */
 355 extern bool rediscover_loops_after_threading;
 356
 357 /* Signalize the status of profile information in the CFG.  */
 358 extern enum profile_status
 359 {
 360   PROFILE_ABSENT,
 361   PROFILE_GUESSED,
 362   PROFILE_READ
 363 } profile_status;
 364
 365 /* Index by basic block number, get basic block struct info.  */
 366
 367 extern GTY(()) varray_type basic_block_info;
 368
 369 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 370
 371 /* For iterating over basic blocks.  */
 372 #define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \
 373   for (BB = FROM; BB != TO; BB = BB->DIR)
 374
 375 #define FOR_EACH_BB(BB) \
 376   FOR_BB_BETWEEN (BB, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR, next_bb)
 377
 378 #define FOR_EACH_BB_REVERSE(BB) \
 379   FOR_BB_BETWEEN (BB, EXIT_BLOCK_PTR->prev_bb, ENTRY_BLOCK_PTR, prev_bb)
 380
 381 /* For iterating over insns in basic block.  */
 382 #define FOR_BB_INSNS(BB, INSN)                  \
 383   for ((INSN) = BB_HEAD (BB);                   \
 384        (INSN) != NEXT_INSN (BB_END (BB));       \
 385        (INSN) = NEXT_INSN (INSN))
 386
 387 #define FOR_BB_INSNS_REVERSE(BB, INSN)          \
 388   for ((INSN) = BB_END (BB);                    \
 389        (INSN) != PREV_INSN (BB_HEAD (BB));      \
 390        (INSN) = PREV_INSN (INSN))
 391
 392 /* Cycles through _all_ basic blocks, even the fake ones (entry and
 393    exit block).  */
 394
 395 #define FOR_ALL_BB(BB) \
 396   for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)
 397
 398 /* Special labels found during CFG build.  */
 399
 400 extern GTY(()) rtx label_value_list;
 401
 402 extern bitmap_obstack reg_obstack;
 403
 404 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 405    If the value is REG_BLOCK_GLOBAL (-2),
 406    it means (REG n) is used in more than one basic block.
 407    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 408    This information remains valid for the rest of the compilation
 409    of the current function; it is used to control register allocation.  */
 410
 411 #define REG_BLOCK_UNKNOWN -1
 412 #define REG_BLOCK_GLOBAL -2
 413
 414 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 415 \f
 416 /* Stuff for recording basic block info.  */
 417
 418 #define BB_HEAD(B)      (B)->head_
 419 #define BB_END(B)       (B)->end_
 420
 421 /* Special block numbers [markers] for entry and exit.  */
 422 #define ENTRY_BLOCK (-1)
 423 #define EXIT_BLOCK (-2)
 424
 425 /* Special block number not valid for any block.  */
 426 #define INVALID_BLOCK (-3)
 427
 428 /* Similarly, block pointers for the edge list.  */
 429 extern GTY(()) basic_block ENTRY_BLOCK_PTR;
 430 extern GTY(()) basic_block EXIT_BLOCK_PTR;
 431
 432 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 433 #define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)
 434
 435 extern void compute_bb_for_insn (void);
 436 extern void free_bb_for_insn (void);
 437 extern void update_bb_for_insn (basic_block);
 438
 439 extern void free_basic_block_vars (void);
 440
 441 extern void insert_insn_on_edge (rtx, edge);
 442 bool safe_insert_insn_on_edge (rtx, edge);
 443
 444 extern void commit_edge_insertions (void);
 445 extern void commit_edge_insertions_watch_calls (void);
 446
 447 extern void remove_fake_edges (void);
 448 extern void remove_fake_exit_edges (void);
 449 extern void add_noreturn_fake_exit_edges (void);
 450 extern void connect_infinite_loops_to_exit (void);
 451 extern edge unchecked_make_edge (basic_block, basic_block, int);
 452 extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);
 453 extern edge make_edge (basic_block, basic_block, int);
 454 extern edge make_single_succ_edge (basic_block, basic_block, int);
 455 extern void remove_edge (edge);
 456 extern void redirect_edge_succ (edge, basic_block);
 457 extern edge redirect_edge_succ_nodup (edge, basic_block);
 458 extern void redirect_edge_pred (edge, basic_block);
 459 extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);
 460 extern void clear_bb_flags (void);
 461 extern void flow_reverse_top_sort_order_compute (int *);
 462 extern int flow_depth_first_order_compute (int *, int *);
 463 extern int dfs_enumerate_from (basic_block, int,
 464                                bool (*)(basic_block, void *),
 465                                basic_block *, int, void *);
 466 extern void compute_dominance_frontiers (bitmap *);
 467 extern void dump_edge_info (FILE *, edge, int);
 468 extern void brief_dump_cfg (FILE *);
 469 extern void clear_edges (void);
 470 extern rtx first_insn_after_basic_block_note (basic_block);
 471
 472 /* Structure to group all of the information to process IF-THEN and
 473    IF-THEN-ELSE blocks for the conditional execution support.  This
 474    needs to be in a public file in case the IFCVT macros call
 475    functions passing the ce_if_block data structure.  */
 476
 477 typedef struct ce_if_block
 478 {
 479   basic_block test_bb;                  /* First test block.  */
 480   basic_block then_bb;                  /* THEN block.  */
 481   basic_block else_bb;                  /* ELSE block or NULL.  */
 482   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
 483   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
 484   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
 485   int num_and_and_blocks;               /* # of && blocks.  */
 486   int num_or_or_blocks;                 /* # of || blocks.  */
 487   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
 488   int and_and_p;                        /* Complex test is &&.  */
 489   int num_then_insns;                   /* # of insns in THEN block.  */
 490   int num_else_insns;                   /* # of insns in ELSE block.  */
 491   int pass;                             /* Pass number.  */
 492
 493 #ifdef IFCVT_EXTRA_FIELDS
 494   IFCVT_EXTRA_FIELDS                    /* Any machine dependent fields.  */
 495 #endif
 496
 497 } ce_if_block_t;
 498
 499 /* This structure maintains an edge list vector.  */
 500 struct edge_list
 501 {
 502   int num_blocks;
 503   int num_edges;
 504   edge *index_to_edge;
 505 };
 506
 507 /* This is the value which indicates no edge is present.  */
 508 #define EDGE_INDEX_NO_EDGE      -1
 509
 510 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 511    if there is no edge between the 2 basic blocks.  */
 512 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 513
 514 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 515    block which is either the pred or succ end of the indexed edge.  */
 516 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 517 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 518
 519 /* INDEX_EDGE returns a pointer to the edge.  */
 520 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 521
 522 /* Number of edges in the compressed edge list.  */
 523 #define NUM_EDGES(el)                   ((el)->num_edges)
 524
 525 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 526 #define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 527                                          ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))
 528
 529 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 530 #define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \
 531                                          ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))
 532
 533 /* Return expected execution frequency of the edge E.  */
 534 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 535                                           * (e)->probability \
 536                                           + REG_BR_PROB_BASE / 2) \
 537                                          / REG_BR_PROB_BASE)
 538
 539 /* Return nonzero if edge is critical.  */
 540 #define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \
 541                                          && EDGE_COUNT ((e)->dest->preds) >= 2)
 542
 543 #define EDGE_COUNT(ev)                  VEC_length (edge, (ev))
 544 #define EDGE_I(ev,i)                    VEC_index  (edge, (ev), (i))
 545 #define EDGE_PRED(bb,i)                 VEC_index  (edge, (bb)->preds, (i))
 546 #define EDGE_SUCC(bb,i)                 VEC_index  (edge, (bb)->succs, (i))
 547
 548 /* Returns true if BB has precisely one successor.  */
 549
 550 static inline bool
 551 single_succ_p (basic_block bb)
 552 {
 553   return EDGE_COUNT (bb->succs) == 1;
 554 }
 555
 556 /* Returns true if BB has precisely one predecessor.  */
 557
 558 static inline bool
 559 single_pred_p (basic_block bb)
 560 {
 561   return EDGE_COUNT (bb->preds) == 1;
 562 }
 563
 564 /* Returns the single successor edge of basic block BB.  Aborts if
 565    BB does not have exactly one successor.  */
 566
 567 static inline edge
 568 single_succ_edge (basic_block bb)
 569 {
 570   gcc_assert (single_succ_p (bb));
 571   return EDGE_SUCC (bb, 0);
 572 }
 573
 574 /* Returns the single predecessor edge of basic block BB.  Aborts
 575    if BB does not have exactly one predecessor.  */
 576
 577 static inline edge
 578 single_pred_edge (basic_block bb)
 579 {
 580   gcc_assert (single_pred_p (bb));
 581   return EDGE_PRED (bb, 0);
 582 }
 583
 584 /* Returns the single successor block of basic block BB.  Aborts
 585    if BB does not have exactly one successor.  */
 586
 587 static inline basic_block
 588 single_succ (basic_block bb)
 589 {
 590   return single_succ_edge (bb)->dest;
 591 }
 592
 593 /* Returns the single predecessor block of basic block BB.  Aborts
 594    if BB does not have exactly one predecessor.*/
 595
 596 static inline basic_block
 597 single_pred (basic_block bb)
 598 {
 599   return single_pred_edge (bb)->src;
 600 }
 601
 602 /* Iterator object for edges.  */
 603
 604 typedef struct {
 605   unsigned index;
 606   VEC(edge) **container;
 607 } edge_iterator;
 608
 609 static inline VEC(edge) *
 610 ei_container (edge_iterator i)
 611 {
 612   gcc_assert (i.container);
 613   return *i.container;
 614 }
 615
 616 #define ei_start(iter) ei_start_1 (&(iter))
 617 #define ei_last(iter) ei_last_1 (&(iter))
 618
 619 /* Return an iterator pointing to the start of an edge vector.  */
 620 static inline edge_iterator
 621 ei_start_1 (VEC(edge) **ev)
 622 {
 623   edge_iterator i;
 624
 625   i.index = 0;
 626   i.container = ev;
 627
 628   return i;
 629 }
 630
 631 /* Return an iterator pointing to the last element of an edge
 632    vector.  */
 633 static inline edge_iterator
 634 ei_last_1 (VEC(edge) **ev)
 635 {
 636   edge_iterator i;
 637
 638   i.index = EDGE_COUNT (*ev) - 1;
 639   i.container = ev;
 640
 641   return i;
 642 }
 643
 644 /* Is the iterator `i' at the end of the sequence?  */
 645 static inline bool
 646 ei_end_p (edge_iterator i)
 647 {
 648   return (i.index == EDGE_COUNT (ei_container (i)));
 649 }
 650
 651 /* Is the iterator `i' at one position before the end of the
 652    sequence?  */
 653 static inline bool
 654 ei_one_before_end_p (edge_iterator i)
 655 {
 656   return (i.index + 1 == EDGE_COUNT (ei_container (i)));
 657 }
 658
 659 /* Advance the iterator to the next element.  */
 660 static inline void
 661 ei_next (edge_iterator *i)
 662 {
 663   gcc_assert (i->index < EDGE_COUNT (ei_container (*i)));
 664   i->index++;
 665 }
 666
 667 /* Move the iterator to the previous element.  */
 668 static inline void
 669 ei_prev (edge_iterator *i)
 670 {
 671   gcc_assert (i->index > 0);
 672   i->index--;
 673 }
 674
 675 /* Return the edge pointed to by the iterator `i'.  */
 676 static inline edge
 677 ei_edge (edge_iterator i)
 678 {
 679   return EDGE_I (ei_container (i), i.index);
 680 }
 681
 682 /* Return an edge pointed to by the iterator.  Do it safely so that
 683    NULL is returned when the iterator is pointing at the end of the
 684    sequence.  */
 685 static inline edge
 686 ei_safe_edge (edge_iterator i)
 687 {
 688   return !ei_end_p (i) ? ei_edge (i) : NULL;
 689 }
 690
 691 /* This macro serves as a convenient way to iterate each edge in a
 692    vector of predecessor or successor edges.  It must not be used when
 693    an element might be removed during the traversal, otherwise
 694    elements will be missed.  Instead, use a for-loop like that shown
 695    in the following pseudo-code:
 696
 697    FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 698      {
 699         IF (e != taken_edge)
 700           remove_edge (e);
 701         ELSE
 702           ei_next (&ei);
 703      }
 704 */
 705
 706 #define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC) \
 707   for ((EDGE) = NULL, (ITER) = ei_start ((EDGE_VEC)); \
 708        ((EDGE) = ei_safe_edge ((ITER))); \
 709        ei_next (&(ITER)))
 710
 711 struct edge_list * create_edge_list (void);
 712 void free_edge_list (struct edge_list *);
 713 void print_edge_list (FILE *, struct edge_list *);
 714 void verify_edge_list (FILE *, struct edge_list *);
 715 int find_edge_index (struct edge_list *, basic_block, basic_block);
 716 edge find_edge (basic_block, basic_block);
 717
 718
 719 enum update_life_extent
 720 {
 721   UPDATE_LIFE_LOCAL = 0,
 722   UPDATE_LIFE_GLOBAL = 1,
 723   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 724 };
 725
 726 /* Flags for life_analysis and update_life_info.  */
 727
 728 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 729 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 730 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 731 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 732 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 733 #define PROP_ALLOW_CFG_CHANGES  32      /* Allow the CFG to be changed
 734                                            by dead code removal.  */
 735 #define PROP_AUTOINC            64      /* Create autoinc mem references.  */
 736 #define PROP_EQUAL_NOTES        128     /* Take into account REG_EQUAL notes.  */
 737 #define PROP_SCAN_DEAD_STORES   256     /* Scan for dead code.  */
 738 #define PROP_ASM_SCAN           512     /* Internal flag used within flow.c
 739                                            to flag analysis of asms.  */
 740 #define PROP_FINAL              (PROP_DEATH_NOTES | PROP_LOG_LINKS  \
 741                                  | PROP_REG_INFO | PROP_KILL_DEAD_CODE  \
 742                                  | PROP_SCAN_DEAD_CODE | PROP_AUTOINC \
 743                                  | PROP_ALLOW_CFG_CHANGES \
 744                                  | PROP_SCAN_DEAD_STORES)
 745 #define PROP_POSTRELOAD         (PROP_DEATH_NOTES  \
 746                                  | PROP_KILL_DEAD_CODE  \
 747                                  | PROP_SCAN_DEAD_CODE \
 748                                  | PROP_SCAN_DEAD_STORES)
 749
 750 #define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations
 751                                            except for edge forwarding */
 752 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 753 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 754                                            to care REG_DEAD notes.  */
 755 #define CLEANUP_PRE_LOOP        8       /* Take care to preserve syntactic loop
 756                                            notes.  */
 757 #define CLEANUP_UPDATE_LIFE     16      /* Keep life information up to date.  */
 758 #define CLEANUP_THREADING       32      /* Do jump threading.  */
 759 #define CLEANUP_NO_INSN_DEL     64      /* Do not try to delete trivially dead
 760                                            insns.  */
 761 #define CLEANUP_CFGLAYOUT       128     /* Do cleanup in cfglayout mode.  */
 762 #define CLEANUP_LOG_LINKS       256     /* Update log links.  */
 763
 764 extern void life_analysis (FILE *, int);
 765 extern int update_life_info (sbitmap, enum update_life_extent, int);
 766 extern int update_life_info_in_dirty_blocks (enum update_life_extent, int);
 767 extern int count_or_remove_death_notes (sbitmap, int);
 768 extern int propagate_block (basic_block, regset, regset, regset, int);
 769
 770 struct propagate_block_info;
 771 extern rtx propagate_one_insn (struct propagate_block_info *, rtx);
 772 extern struct propagate_block_info *init_propagate_block_info
 773  (basic_block, regset, regset, regset, int);
 774 extern void free_propagate_block_info (struct propagate_block_info *);
 775
 776 /* In lcm.c */
 777 extern struct edge_list *pre_edge_lcm (FILE *, int, sbitmap *, sbitmap *,
 778                                        sbitmap *, sbitmap *, sbitmap **,
 779                                        sbitmap **);
 780 extern struct edge_list *pre_edge_rev_lcm (FILE *, int, sbitmap *,
 781                                            sbitmap *, sbitmap *,
 782                                            sbitmap *, sbitmap **,
 783                                            sbitmap **);
 784 extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);
 785 extern int optimize_mode_switching (FILE *);
 786
 787 /* In predict.c */
 788 extern void estimate_probability (struct loops *);
 789 extern void expected_value_to_br_prob (void);
 790 extern bool maybe_hot_bb_p (basic_block);
 791 extern bool probably_cold_bb_p (basic_block);
 792 extern bool probably_never_executed_bb_p (basic_block);
 793 extern bool tree_predicted_by_p (basic_block, enum br_predictor);
 794 extern bool rtl_predicted_by_p (basic_block, enum br_predictor);
 795 extern void tree_predict_edge (edge, enum br_predictor, int);
 796 extern void rtl_predict_edge (edge, enum br_predictor, int);
 797 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
 798 extern void guess_outgoing_edge_probabilities (basic_block);
 799
 800 /* In flow.c */
 801 extern void init_flow (void);
 802 extern void debug_bb (basic_block);
 803 extern basic_block debug_bb_n (int);
 804 extern void dump_regset (regset, FILE *);
 805 extern void debug_regset (regset);
 806 extern void allocate_reg_life_data (void);
 807 extern void expunge_block (basic_block);
 808 extern void link_block (basic_block, basic_block);
 809 extern void unlink_block (basic_block);
 810 extern void compact_blocks (void);
 811 extern basic_block alloc_block (void);
 812 extern void find_unreachable_blocks (void);
 813 extern int delete_noop_moves (void);
 814 extern basic_block force_nonfallthru (edge);
 815 extern rtx block_label (basic_block);
 816 extern bool forwarder_block_p (basic_block);
 817 extern bool purge_all_dead_edges (int);
 818 extern bool purge_dead_edges (basic_block);
 819 extern void find_many_sub_basic_blocks (sbitmap);
 820 extern void rtl_make_eh_edge (sbitmap, basic_block, rtx);
 821 extern bool can_fallthru (basic_block, basic_block);
 822 extern bool could_fall_through (basic_block, basic_block);
 823 extern void flow_nodes_print (const char *, const sbitmap, FILE *);
 824 extern void flow_edge_list_print (const char *, const edge *, int, FILE *);
 825 extern void alloc_aux_for_block (basic_block, int);
 826 extern void alloc_aux_for_blocks (int);
 827 extern void clear_aux_for_blocks (void);
 828 extern void free_aux_for_blocks (void);
 829 extern void alloc_aux_for_edge (edge, int);
 830 extern void alloc_aux_for_edges (int);
 831 extern void clear_aux_for_edges (void);
 832 extern void free_aux_for_edges (void);
 833 extern void find_basic_blocks (rtx);
 834 extern bool cleanup_cfg (int);
 835 extern bool delete_unreachable_blocks (void);
 836 extern bool merge_seq_blocks (void);
 837
 838 typedef struct conflict_graph_def *conflict_graph;
 839
 840 /* Callback function when enumerating conflicts.  The arguments are
 841    the smaller and larger regno in the conflict.  Returns zero if
 842    enumeration is to continue, nonzero to halt enumeration.  */
 843 typedef int (*conflict_graph_enum_fn) (int, int, void *);
 844
 845
 846 /* Prototypes of operations on conflict graphs.  */
 847
 848 extern conflict_graph conflict_graph_new
 849  (int);
 850 extern void conflict_graph_delete (conflict_graph);
 851 extern int conflict_graph_add (conflict_graph, int, int);
 852 extern int conflict_graph_conflict_p (conflict_graph, int, int);
 853 extern void conflict_graph_enum (conflict_graph, int, conflict_graph_enum_fn,
 854                                  void *);
 855 extern void conflict_graph_merge_regs (conflict_graph, int, int);
 856 extern void conflict_graph_print (conflict_graph, FILE*);
 857 extern bool mark_dfs_back_edges (void);
 858 extern void set_edge_can_fallthru_flag (void);
 859 extern void update_br_prob_note (basic_block);
 860 extern void fixup_abnormal_edges (void);
 861 extern bool inside_basic_block_p (rtx);
 862 extern bool control_flow_insn_p (rtx);
 863
 864 /* In bb-reorder.c */
 865 extern void reorder_basic_blocks (unsigned int);
 866 extern void duplicate_computed_gotos (void);
 867 extern void partition_hot_cold_basic_blocks (void);
 868
 869 /* In cfg.c */
 870 extern void alloc_rbi_pool (void);
 871 extern void initialize_bb_rbi (basic_block bb);
 872 extern void free_rbi_pool (void);
 873
 874 /* In dominance.c */
 875
 876 enum cdi_direction
 877 {
 878   CDI_DOMINATORS,
 879   CDI_POST_DOMINATORS
 880 };
 881
 882 enum dom_state
 883 {
 884   DOM_NONE,             /* Not computed at all.  */
 885   DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */
 886   DOM_OK                /* Everything is ok.  */
 887 };
 888
 889 extern enum dom_state dom_computed[2];
 890
 891 extern bool dom_info_available_p (enum cdi_direction);
 892 extern void calculate_dominance_info (enum cdi_direction);
 893 extern void free_dominance_info (enum cdi_direction);
 894 extern basic_block nearest_common_dominator (enum cdi_direction,
 895                                              basic_block, basic_block);
 896 extern void set_immediate_dominator (enum cdi_direction, basic_block,
 897                                      basic_block);
 898 extern basic_block get_immediate_dominator (enum cdi_direction, basic_block);
 899 extern bool dominated_by_p (enum cdi_direction, basic_block, basic_block);
 900 extern int get_dominated_by (enum cdi_direction, basic_block, basic_block **);
 901 extern unsigned get_dominated_by_region (enum cdi_direction, basic_block *,
 902                                          unsigned, basic_block *);
 903 extern void add_to_dominance_info (enum cdi_direction, basic_block);
 904 extern void delete_from_dominance_info (enum cdi_direction, basic_block);
 905 basic_block recount_dominator (enum cdi_direction, basic_block);
 906 extern void redirect_immediate_dominators (enum cdi_direction, basic_block,
 907                                            basic_block);
 908 extern void iterate_fix_dominators (enum cdi_direction, basic_block *, int);
 909 extern void verify_dominators (enum cdi_direction);
 910 extern basic_block first_dom_son (enum cdi_direction, basic_block);
 911 extern basic_block next_dom_son (enum cdi_direction, basic_block);
 912 extern edge try_redirect_by_replacing_jump (edge, basic_block, bool);
 913 extern void break_superblocks (void);
 914 extern void check_bb_profile (basic_block, FILE *);
 915 extern void update_bb_profile_for_threading (basic_block, int, gcov_type, edge);
 916
 917 #include "cfghooks.h"
 918
 919 #endif /* GCC_BASIC_BLOCK_H */