gcc/basic-block.h

   1 /* Define control and data flow tables, and regsets.
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #ifndef GCC_BASIC_BLOCK_H
  22 #define GCC_BASIC_BLOCK_H
  23
  24 #include "bitmap.h"
  25 #include "sbitmap.h"
  26 #include "varray.h"
  27 #include "partition.h"
  28
  29 #ifndef TREE_CODE
  30 union tree_node;
  31 #define tree union tree_node *
  32 #endif
  33
  34 /* Head of register set linked list.  */
  35 typedef bitmap_head regset_head;
  36 /* A pointer to a regset_head.  */
  37 typedef bitmap regset;
  38
  39 /* Initialize a new regset.  */
  40 #define INIT_REG_SET(HEAD) bitmap_initialize (HEAD)
  41
  42 /* Clear a register set by freeing up the linked list.  */
  43 #define CLEAR_REG_SET(HEAD) bitmap_clear (HEAD)
  44
  45 /* Copy a register set to another register set.  */
  46 #define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
  47
  48 /* Compare two register sets.  */
  49 #define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
  50
  51 /* `and' a register set with a second register set.  */
  52 #define AND_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_AND)
  53
  54 /* `and' the complement of a register set with a register set.  */
  55 #define AND_COMPL_REG_SET(TO, FROM) \
  56   bitmap_operation (TO, TO, FROM, BITMAP_AND_COMPL)
  57
  58 /* Inclusive or a register set with a second register set.  */
  59 #define IOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_IOR)
  60
  61 /* Exclusive or a register set with a second register set.  */
  62 #define XOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_XOR)
  63
  64 /* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
  65 #define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
  66   bitmap_ior_and_compl (TO, FROM1, FROM2)
  67
  68 /* Clear a single register in a register set.  */
  69 #define CLEAR_REGNO_REG_SET(HEAD, REG) bitmap_clear_bit (HEAD, REG)
  70
  71 /* Set a single register in a register set.  */
  72 #define SET_REGNO_REG_SET(HEAD, REG) bitmap_set_bit (HEAD, REG)
  73
  74 /* Return true if a register is set in a register set.  */
  75 #define REGNO_REG_SET_P(TO, REG) bitmap_bit_p (TO, REG)
  76
  77 /* Copy the hard registers in a register set to the hard register set.  */
  78 extern void reg_set_to_hard_reg_set PARAMS ((HARD_REG_SET *, bitmap));
  79 #define REG_SET_TO_HARD_REG_SET(TO, FROM)                               \
  80 do {                                                                    \
  81   CLEAR_HARD_REG_SET (TO);                                              \
  82   reg_set_to_hard_reg_set (&TO, FROM);                                  \
  83 } while (0)
  84
  85 /* Loop over all registers in REGSET, starting with MIN, setting REGNUM to the
  86    register number and executing CODE for all registers that are set. */
  87 #define EXECUTE_IF_SET_IN_REG_SET(REGSET, MIN, REGNUM, CODE)            \
  88   EXECUTE_IF_SET_IN_BITMAP (REGSET, MIN, REGNUM, CODE)
  89
  90 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  91    REGNUM to the register number and executing CODE for all registers that are
  92    set in the first regset and not set in the second. */
  93 #define EXECUTE_IF_AND_COMPL_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
  94   EXECUTE_IF_AND_COMPL_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
  95
  96 /* Loop over all registers in REGSET1 and REGSET2, starting with MIN, setting
  97    REGNUM to the register number and executing CODE for all registers that are
  98    set in both regsets. */
  99 #define EXECUTE_IF_AND_IN_REG_SET(REGSET1, REGSET2, MIN, REGNUM, CODE) \
 100   EXECUTE_IF_AND_IN_BITMAP (REGSET1, REGSET2, MIN, REGNUM, CODE)
 101
 102 /* Allocate a register set with oballoc.  */
 103 #define OBSTACK_ALLOC_REG_SET(OBSTACK) BITMAP_OBSTACK_ALLOC (OBSTACK)
 104
 105 /* Initialize a register set.  Returns the new register set.  */
 106 #define INITIALIZE_REG_SET(HEAD) bitmap_initialize (&HEAD)
 107
 108 /* Do any cleanup needed on a regset when it is no longer used.  */
 109 #define FREE_REG_SET(REGSET) BITMAP_FREE(REGSET)
 110
 111 /* Do any one-time initializations needed for regsets.  */
 112 #define INIT_ONCE_REG_SET() BITMAP_INIT_ONCE ()
 113
 114 /* Grow any tables needed when the number of registers is calculated
 115    or extended.  For the linked list allocation, nothing needs to
 116    be done, other than zero the statistics on the first allocation.  */
 117 #define MAX_REGNO_REG_SET(NUM_REGS, NEW_P, RENUMBER_P)
 118
 119 /* Type we use to hold basic block counters.  Should be at least 64bit.  */
 120 typedef HOST_WIDEST_INT gcov_type;
 121
 122 /* Control flow edge information.  */
 123 typedef struct edge_def {
 124   /* Links through the predecessor and successor lists.  */
 125   struct edge_def *pred_next, *succ_next;
 126
 127   /* The two blocks at the ends of the edge.  */
 128   struct basic_block_def *src, *dest;
 129
 130   /* Instructions queued on the edge.  */
 131   rtx insns;
 132
 133   /* Auxiliary info specific to a pass.  */
 134   void *aux;
 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 } *edge;
 141
 142 #define EDGE_FALLTHRU           1
 143 #define EDGE_CRITICAL           2
 144 #define EDGE_ABNORMAL           4
 145 #define EDGE_ABNORMAL_CALL      8
 146 #define EDGE_EH                 16
 147 #define EDGE_FAKE               32
 148 #define EDGE_DFS_BACK           64
 149
 150 #define EDGE_COMPLEX    (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
 151
 152
 153 /* A basic block is a sequence of instructions with only entry and
 154    only one exit.  If any one of the instructions are executed, they
 155    will all be executed, and in sequence from first to last.
 156
 157    There may be COND_EXEC instructions in the basic block.  The
 158    COND_EXEC *instructions* will be executed -- but if the condition
 159    is false the conditionally executed *expressions* will of course
 160    not be executed.  We don't consider the conditionally executed
 161    expression (which might have side-effects) to be in a separate
 162    basic block because the program counter will always be at the same
 163    location after the COND_EXEC instruction, regardless of whether the
 164    condition is true or not.
 165
 166    Basic blocks need not start with a label nor end with a jump insn.
 167    For example, a previous basic block may just "conditionally fall"
 168    into the succeeding basic block, and the last basic block need not
 169    end with a jump insn.  Block 0 is a descendant of the entry block.
 170
 171    A basic block beginning with two labels cannot have notes between
 172    the labels.
 173
 174    Data for jump tables are stored in jump_insns that occur in no
 175    basic block even though these insns can follow or precede insns in
 176    basic blocks.  */
 177
 178 /* Basic block information indexed by block number.  */
 179 typedef struct basic_block_def {
 180   /* The first and last insns of the block.  */
 181   rtx head, end;
 182
 183   /* The first and last trees of the block.  */
 184   tree head_tree;
 185   tree end_tree;
 186
 187   /* The edges into and out of the block.  */
 188   edge pred, succ;
 189
 190   /* Liveness info.  */
 191
 192   /* The registers that are modified within this in block.  */
 193   regset local_set;
 194   /* The registers that are conditionally modified within this block.
 195      In other words, registers that are set only as part of a
 196      COND_EXEC.  */
 197   regset cond_local_set;
 198   /* The registers that are live on entry to this block.
 199
 200      Note that in SSA form, global_live_at_start does not reflect the
 201      use of regs in phi functions, since the liveness of these regs
 202      may depend on which edge was taken into the block.  */
 203   regset global_live_at_start;
 204   /* The registers that are live on exit from this block.  */
 205   regset global_live_at_end;
 206
 207   /* Auxiliary info specific to a pass.  */
 208   void *aux;
 209
 210   /* The index of this block.  */
 211   int index;
 212
 213   /* The loop depth of this block.  */
 214   int loop_depth;
 215
 216   /* Expected number of executions: calculated in profile.c.  */
 217   gcov_type count;
 218
 219   /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */
 220   int frequency;
 221
 222   /* Various flags.  See BB_* below.  */
 223   int flags;
 224 } *basic_block;
 225
 226 #define BB_FREQ_MAX 10000
 227
 228 /* Masks for basic_block.flags.  */
 229 #define BB_REACHABLE            1
 230
 231 /* Number of basic blocks in the current function.  */
 232
 233 extern int n_basic_blocks;
 234
 235 /* Number of edges in the current function.  */
 236
 237 extern int n_edges;
 238
 239 /* Index by basic block number, get basic block struct info.  */
 240
 241 extern varray_type basic_block_info;
 242
 243 #define BASIC_BLOCK(N)  (VARRAY_BB (basic_block_info, (N)))
 244
 245 /* What registers are live at the setjmp call.  */
 246
 247 extern regset regs_live_at_setjmp;
 248
 249 /* Indexed by n, gives number of basic block that  (REG n) is used in.
 250    If the value is REG_BLOCK_GLOBAL (-2),
 251    it means (REG n) is used in more than one basic block.
 252    REG_BLOCK_UNKNOWN (-1) means it hasn't been seen yet so we don't know.
 253    This information remains valid for the rest of the compilation
 254    of the current function; it is used to control register allocation.  */
 255
 256 #define REG_BLOCK_UNKNOWN -1
 257 #define REG_BLOCK_GLOBAL -2
 258
 259 #define REG_BASIC_BLOCK(N) (VARRAY_REG (reg_n_info, N)->basic_block)
 260 \f
 261 /* Stuff for recording basic block info.  */
 262
 263 #define BLOCK_HEAD(B)      (BASIC_BLOCK (B)->head)
 264 #define BLOCK_END(B)       (BASIC_BLOCK (B)->end)
 265
 266 #define BLOCK_HEAD_TREE(B) (BASIC_BLOCK (B)->head_tree)
 267 #define BLOCK_END_TREE(B) (BASIC_BLOCK (B)->end_tree)
 268
 269 /* Special block numbers [markers] for entry and exit.  */
 270 #define ENTRY_BLOCK (-1)
 271 #define EXIT_BLOCK (-2)
 272
 273 /* Special block number not valid for any block. */
 274 #define INVALID_BLOCK (-3)
 275
 276 /* Similarly, block pointers for the edge list.  */
 277 extern struct basic_block_def entry_exit_blocks[2];
 278 #define ENTRY_BLOCK_PTR (&entry_exit_blocks[0])
 279 #define EXIT_BLOCK_PTR  (&entry_exit_blocks[1])
 280
 281 extern varray_type basic_block_for_insn;
 282 #define BLOCK_FOR_INSN(INSN)  VARRAY_BB (basic_block_for_insn, INSN_UID (INSN))
 283 #define BLOCK_NUM(INSN)       (BLOCK_FOR_INSN (INSN)->index + 0)
 284
 285 extern void compute_bb_for_insn         PARAMS ((int));
 286 extern void update_bb_for_insn          PARAMS ((basic_block));
 287 extern void set_block_for_insn          PARAMS ((rtx, basic_block));
 288 extern void set_block_for_new_insns     PARAMS ((rtx, basic_block));
 289
 290 extern void free_basic_block_vars       PARAMS ((int));
 291
 292 extern edge split_block                 PARAMS ((basic_block, rtx));
 293 extern basic_block split_edge           PARAMS ((edge));
 294 extern void insert_insn_on_edge         PARAMS ((rtx, edge));
 295 extern void commit_edge_insertions      PARAMS ((void));
 296 extern void remove_fake_edges           PARAMS ((void));
 297 extern void add_noreturn_fake_exit_edges        PARAMS ((void));
 298 extern void connect_infinite_loops_to_exit      PARAMS ((void));
 299 extern int flow_call_edges_add          PARAMS ((sbitmap));
 300 extern rtx flow_delete_insn             PARAMS ((rtx));
 301 extern void flow_delete_insn_chain      PARAMS ((rtx, rtx));
 302 extern void make_edge                   PARAMS ((sbitmap *, basic_block,
 303                                                  basic_block, int));
 304 extern void remove_edge                 PARAMS ((edge));
 305 extern void redirect_edge_succ          PARAMS ((edge, basic_block));
 306 extern edge redirect_edge_succ_nodup    PARAMS ((edge, basic_block));
 307 extern void redirect_edge_pred          PARAMS ((edge, basic_block));
 308 extern void create_basic_block          PARAMS ((int, rtx, rtx, rtx));
 309 extern int flow_delete_block            PARAMS ((basic_block));
 310 extern void merge_blocks_nomove         PARAMS ((basic_block, basic_block));
 311 extern void tidy_fallthru_edge          PARAMS ((edge, basic_block,
 312                                                  basic_block));
 313 extern void flow_reverse_top_sort_order_compute PARAMS ((int *));
 314 extern int flow_depth_first_order_compute       PARAMS ((int *, int *));
 315 extern void dump_edge_info              PARAMS ((FILE *, edge, int));
 316 extern void clear_edges                 PARAMS ((void));
 317 extern void mark_critical_edges         PARAMS ((void));
 318 extern rtx first_insn_after_basic_block_note    PARAMS ((basic_block));
 319
 320 /* Structure to hold information for each natural loop.  */
 321 struct loop
 322 {
 323   /* Index into loops array.  */
 324   int num;
 325
 326   /* Basic block of loop header.  */
 327   basic_block header;
 328
 329   /* Basic block of loop latch.  */
 330   basic_block latch;
 331
 332   /* Basic block of loop pre-header or NULL if it does not exist.  */
 333   basic_block pre_header;
 334
 335   /* Array of edges along the pre-header extended basic block trace.
 336      The source of the first edge is the root node of pre-header
 337      extended basic block, if it exists.  */
 338   edge *pre_header_edges;
 339
 340   /* Number of edges along the pre_header extended basic block trace.  */
 341   int num_pre_header_edges;
 342
 343   /* The first block in the loop.  This is not necessarily the same as
 344      the loop header.  */
 345   basic_block first;
 346
 347   /* The last block in the loop.  This is not necessarily the same as
 348      the loop latch.  */
 349   basic_block last;
 350
 351   /* Bitmap of blocks contained within the loop.  */
 352   sbitmap nodes;
 353
 354   /* Number of blocks contained within the loop.  */
 355   int num_nodes;
 356
 357   /* Array of edges that enter the loop.  */
 358   edge *entry_edges;
 359
 360   /* Number of edges that enter the loop.  */
 361   int num_entries;
 362
 363   /* Array of edges that exit the loop.  */
 364   edge *exit_edges;
 365
 366   /* Number of edges that exit the loop.  */
 367   int num_exits;
 368
 369   /* Bitmap of blocks that dominate all exits of the loop.  */
 370   sbitmap exits_doms;
 371
 372   /* The loop nesting depth.  */
 373   int depth;
 374
 375   /* The height of the loop (enclosed loop levels) within the loop
 376      hierarchy tree.  */
 377   int level;
 378
 379   /* The outer (parent) loop or NULL if outermost loop.  */
 380   struct loop *outer;
 381
 382   /* The first inner (child) loop or NULL if innermost loop.  */
 383   struct loop *inner;
 384
 385   /* Link to the next (sibling) loop.  */
 386   struct loop *next;
 387
 388   /* Non-zero if the loop shares a header with another loop.  */
 389   int shared;
 390
 391   /* Non-zero if the loop is invalid (e.g., contains setjmp.).  */
 392   int invalid;
 393
 394   /* Auxiliary info specific to a pass.  */
 395   void *aux;
 396
 397   /* The following are currently used by loop.c but they are likely to
 398      disappear as loop.c is converted to use the CFG.  */
 399
 400   /* Non-zero if the loop has a NOTE_INSN_LOOP_VTOP.  */
 401   rtx vtop;
 402
 403   /* Non-zero if the loop has a NOTE_INSN_LOOP_CONT.
 404      A continue statement will generate a branch to NEXT_INSN (cont).  */
 405   rtx cont;
 406
 407   /* The dominator of cont.  */
 408   rtx cont_dominator;
 409
 410   /* The NOTE_INSN_LOOP_BEG.  */
 411   rtx start;
 412
 413   /* The NOTE_INSN_LOOP_END.  */
 414   rtx end;
 415
 416   /* For a rotated loop that is entered near the bottom,
 417      this is the label at the top.  Otherwise it is zero.  */
 418   rtx top;
 419
 420   /* Place in the loop where control enters.  */
 421   rtx scan_start;
 422
 423   /* The position where to sink insns out of the loop.  */
 424   rtx sink;
 425
 426   /* List of all LABEL_REFs which refer to code labels outside the
 427      loop.  Used by routines that need to know all loop exits, such as
 428      final_biv_value and final_giv_value.
 429
 430      This does not include loop exits due to return instructions.
 431      This is because all bivs and givs are pseudos, and hence must be
 432      dead after a return, so the presense of a return does not affect
 433      any of the optimizations that use this info.  It is simpler to
 434      just not include return instructions on this list.  */
 435   rtx exit_labels;
 436
 437   /* The number of LABEL_REFs on exit_labels for this loop and all
 438      loops nested inside it.  */
 439   int exit_count;
 440 };
 441
 442
 443 /* Structure to hold CFG information about natural loops within a function.  */
 444 struct loops
 445 {
 446   /* Number of natural loops in the function.  */
 447   int num;
 448
 449   /* Maxium nested loop level in the function.  */
 450   int levels;
 451
 452   /* Array of natural loop descriptors (scanning this array in reverse order
 453      will find the inner loops before their enclosing outer loops).  */
 454   struct loop *array;
 455
 456   /* Pointer to root of loop heirachy tree.  */
 457   struct loop *tree_root;
 458
 459   /* Information derived from the CFG.  */
 460   struct cfg
 461   {
 462     /* The bitmap vector of dominators or NULL if not computed.  */
 463     sbitmap *dom;
 464
 465     /* The ordering of the basic blocks in a depth first search.  */
 466     int *dfs_order;
 467
 468     /* The reverse completion ordering of the basic blocks found in a
 469        depth first search.  */
 470     int *rc_order;
 471   } cfg;
 472
 473   /* Headers shared by multiple loops that should be merged.  */
 474   sbitmap shared_headers;
 475 };
 476
 477 extern int flow_loops_find PARAMS ((struct loops *, int flags));
 478 extern int flow_loops_update PARAMS ((struct loops *, int flags));
 479 extern void flow_loops_free PARAMS ((struct loops *));
 480 extern void flow_loops_dump PARAMS ((const struct loops *, FILE *,
 481                                      void (*)(const struct loop *,
 482                                               FILE *, int), int));
 483 extern void flow_loop_dump PARAMS ((const struct loop *, FILE *,
 484                                     void (*)(const struct loop *,
 485                                              FILE *, int), int));
 486 extern int flow_loop_scan PARAMS ((struct loops *, struct loop *, int));
 487
 488 /* This structure maintains an edge list vector.  */
 489 struct edge_list
 490 {
 491   int num_blocks;
 492   int num_edges;
 493   edge *index_to_edge;
 494 };
 495
 496 /* This is the value which indicates no edge is present.  */
 497 #define EDGE_INDEX_NO_EDGE      -1
 498
 499 /* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE
 500    if there is no edge between the 2 basic blocks.  */
 501 #define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))
 502
 503 /* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic
 504    block which is either the pred or succ end of the indexed edge.  */
 505 #define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)
 506 #define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)
 507
 508 /* INDEX_EDGE returns a pointer to the edge.  */
 509 #define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])
 510
 511 /* Number of edges in the compressed edge list.  */
 512 #define NUM_EDGES(el)                   ((el)->num_edges)
 513
 514 /* BB is assumed to contain conditional jump.  Return the fallthru edge.  */
 515 #define FALLTHRU_EDGE(bb)               ((bb)->succ->flags & EDGE_FALLTHRU \
 516                                          ? (bb)->succ : (bb)->succ->succ_next)
 517
 518 /* BB is assumed to contain conditional jump.  Return the branch edge.  */
 519 #define BRANCH_EDGE(bb)                 ((bb)->succ->flags & EDGE_FALLTHRU \
 520                                          ? (bb)->succ->succ_next : (bb)->succ)
 521
 522 /* Return expected execution frequency of the edge E.  */
 523 #define EDGE_FREQUENCY(e)               (((e)->src->frequency \
 524                                           * (e)->probability \
 525                                           + REG_BR_PROB_BASE / 2) \
 526                                          / REG_BR_PROB_BASE)
 527
 528 struct edge_list * create_edge_list     PARAMS ((void));
 529 void free_edge_list                     PARAMS ((struct edge_list *));
 530 void print_edge_list                    PARAMS ((FILE *, struct edge_list *));
 531 void verify_edge_list                   PARAMS ((FILE *, struct edge_list *));
 532 int find_edge_index                     PARAMS ((struct edge_list *,
 533                                                  basic_block, basic_block));
 534
 535
 536 enum update_life_extent
 537 {
 538   UPDATE_LIFE_LOCAL = 0,
 539   UPDATE_LIFE_GLOBAL = 1,
 540   UPDATE_LIFE_GLOBAL_RM_NOTES = 2
 541 };
 542
 543 /* Flags for life_analysis and update_life_info.  */
 544
 545 #define PROP_DEATH_NOTES        1       /* Create DEAD and UNUSED notes.  */
 546 #define PROP_LOG_LINKS          2       /* Create LOG_LINKS.  */
 547 #define PROP_REG_INFO           4       /* Update regs_ever_live et al.  */
 548 #define PROP_KILL_DEAD_CODE     8       /* Remove dead code.  */
 549 #define PROP_SCAN_DEAD_CODE     16      /* Scan for dead code.  */
 550 #define PROP_ALLOW_CFG_CHANGES  32      /* Allow the CFG to be changed
 551                                            by dead code removal.  */
 552 #define PROP_AUTOINC            64      /* Create autoinc mem references.  */
 553 #define PROP_FINAL              127     /* All of the above.  */
 554
 555 #define CLEANUP_EXPENSIVE       1       /* Do relativly expensive optimizations
 556                                            except for edge forwarding */
 557 #define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */
 558 #define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need
 559                                            to care REG_DEAD notes.  */
 560 #define CLEANUP_PRE_SIBCALL     8       /* Do not get confused by code hidden
 561                                            inside call_placeholders..  */
 562 #define CLEANUP_PRE_LOOP        16      /* Take care to preserve syntactic loop
 563                                            notes.  */
 564 /* Flags for loop discovery.  */
 565
 566 #define LOOP_TREE               1       /* Build loop hierarchy tree.  */
 567 #define LOOP_PRE_HEADER         2       /* Analyse loop pre-header.  */
 568 #define LOOP_ENTRY_EDGES        4       /* Find entry edges.  */
 569 #define LOOP_EXIT_EDGES         8       /* Find exit edges.  */
 570 #define LOOP_EDGES              (LOOP_ENTRY_EDGES | LOOP_EXIT_EDGES)
 571 #define LOOP_EXITS_DOMS        16       /* Find nodes that dom. all exits.  */
 572 #define LOOP_ALL               31       /* All of the above  */
 573
 574 extern void life_analysis       PARAMS ((rtx, FILE *, int));
 575 extern void update_life_info    PARAMS ((sbitmap, enum update_life_extent,
 576                                          int));
 577 extern int count_or_remove_death_notes  PARAMS ((sbitmap, int));
 578 extern int propagate_block      PARAMS ((basic_block, regset, regset, regset,
 579                                          int));
 580
 581 struct propagate_block_info;
 582 extern rtx propagate_one_insn   PARAMS ((struct propagate_block_info *, rtx));
 583 extern struct propagate_block_info *init_propagate_block_info
 584   PARAMS ((basic_block, regset, regset, regset, int));
 585 extern void free_propagate_block_info PARAMS ((struct propagate_block_info *));
 586
 587 /* In lcm.c */
 588 extern struct edge_list *pre_edge_lcm   PARAMS ((FILE *, int, sbitmap *,
 589                                                  sbitmap *, sbitmap *,
 590                                                  sbitmap *, sbitmap **,
 591                                                  sbitmap **));
 592 extern struct edge_list *pre_edge_rev_lcm PARAMS ((FILE *, int, sbitmap *,
 593                                                    sbitmap *, sbitmap *,
 594                                                    sbitmap *, sbitmap **,
 595                                                    sbitmap **));
 596 extern void compute_available           PARAMS ((sbitmap *, sbitmap *,
 597                                                  sbitmap *, sbitmap *));
 598 extern int optimize_mode_switching      PARAMS ((FILE *));
 599
 600 /* In emit-rtl.c.  */
 601 extern rtx emit_block_insn_after        PARAMS ((rtx, rtx, basic_block));
 602 extern rtx emit_block_insn_before       PARAMS ((rtx, rtx, basic_block));
 603
 604 /* In predict.c */
 605 extern void estimate_probability        PARAMS ((struct loops *));
 606 extern void expected_value_to_br_prob   PARAMS ((void));
 607
 608 /* In flow.c */
 609 extern void init_flow                   PARAMS ((void));
 610 extern void reorder_basic_blocks        PARAMS ((void));
 611 extern void dump_bb                     PARAMS ((basic_block, FILE *));
 612 extern void debug_bb                    PARAMS ((basic_block));
 613 extern void debug_bb_n                  PARAMS ((int));
 614 extern void dump_regset                 PARAMS ((regset, FILE *));
 615 extern void debug_regset                PARAMS ((regset));
 616 extern void allocate_reg_life_data      PARAMS ((void));
 617 extern void allocate_bb_life_data       PARAMS ((void));
 618 extern void find_unreachable_blocks     PARAMS ((void));
 619 extern void expunge_block               PARAMS ((basic_block));
 620 extern void delete_noop_moves           PARAMS ((rtx));
 621 extern rtx last_loop_beg_note           PARAMS ((rtx));
 622 extern basic_block redirect_edge_and_branch_force PARAMS ((edge, basic_block));
 623 extern bool redirect_edge_and_branch    PARAMS ((edge, basic_block));
 624 extern rtx block_label                  PARAMS ((basic_block));
 625 extern bool forwarder_block_p           PARAMS ((basic_block));
 626 extern bool purge_all_dead_edges        PARAMS ((void));
 627 extern bool purge_dead_edges            PARAMS ((basic_block));
 628 extern void find_sub_basic_blocks       PARAMS ((basic_block));
 629
 630
 631 /* This function is always defined so it can be called from the
 632    debugger, and it is declared extern so we don't get warnings about
 633    it being unused. */
 634 extern void verify_flow_info            PARAMS ((void));
 635 extern int flow_loop_outside_edge_p     PARAMS ((const struct loop *, edge));
 636
 637 typedef struct conflict_graph_def *conflict_graph;
 638
 639 /* Callback function when enumerating conflicts.  The arguments are
 640    the smaller and larger regno in the conflict.  Returns zero if
 641    enumeration is to continue, non-zero to halt enumeration.  */
 642 typedef int (*conflict_graph_enum_fn) PARAMS ((int, int, void *));
 643
 644
 645 /* Prototypes of operations on conflict graphs.  */
 646
 647 extern conflict_graph conflict_graph_new
 648                                         PARAMS ((int));
 649 extern void conflict_graph_delete       PARAMS ((conflict_graph));
 650 extern int conflict_graph_add           PARAMS ((conflict_graph,
 651                                                  int, int));
 652 extern int conflict_graph_conflict_p    PARAMS ((conflict_graph,
 653                                                  int, int));
 654 extern void conflict_graph_enum         PARAMS ((conflict_graph, int,
 655                                                  conflict_graph_enum_fn,
 656                                                  void *));
 657 extern void conflict_graph_merge_regs   PARAMS ((conflict_graph, int,
 658                                                  int));
 659 extern void conflict_graph_print        PARAMS ((conflict_graph, FILE*));
 660 extern conflict_graph conflict_graph_compute
 661                                         PARAMS ((regset,
 662                                                  partition));
 663 extern bool mark_dfs_back_edges         PARAMS ((void));
 664
 665 /* In dominance.c */
 666
 667 enum cdi_direction
 668 {
 669   CDI_DOMINATORS,
 670   CDI_POST_DOMINATORS
 671 };
 672
 673 extern void calculate_dominance_info    PARAMS ((int *, sbitmap *,
 674                                                  enum cdi_direction));
 675
 676 #endif /* GCC_BASIC_BLOCK_H */