Subversion Repositories altor32

/* Define control flow data structures for the CFG.

   Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,

   2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under

the terms of the GNU General Public License as published by the Free

Software Foundation; either version 3, or (at your option) any later

version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or

FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

for more details.

You should have received a copy of the GNU General Public License

along with GCC; see the file COPYING3.  If not see

<http://www.gnu.org/licenses/>.  */

#ifndef GCC_BASIC_BLOCK_H

#define GCC_BASIC_BLOCK_H

#include "predict.h"

#include "vec.h"

#include "function.h"

/* Type we use to hold basic block counters.  Should be at least

   64bit.  Although a counter cannot be negative, we use a signed

   type, because erroneous negative counts can be generated when the

   flow graph is manipulated by various optimizations.  A signed type

   makes those easy to detect.  */

typedef HOST_WIDEST_INT gcov_type;

typedef unsigned HOST_WIDEST_INT gcov_type_unsigned;

/* Control flow edge information.  */

struct GTY((user)) edge_def {

  /* The two blocks at the ends of the edge.  */

  basic_block src;

  basic_block dest;

  /* Instructions queued on the edge.  */

  union edge_def_insns {

    gimple_seq g;

    rtx r;

  } insns;

  /* Auxiliary info specific to a pass.  */

  PTR aux;

  /* Location of any goto implicit in the edge.  */

  location_t goto_locus;

  /* The index number corresponding to this edge in the edge vector

     dest->preds.  */

  unsigned int dest_idx;

  int flags;                    /* see cfg-flags.def */

  int probability;              /* biased by REG_BR_PROB_BASE */

  gcov_type count;              /* Expected number of executions calculated

                                   in profile.c  */

};

/* Garbage collection and PCH support for edge_def.  */

extern void gt_ggc_mx (edge_def *e);

extern void gt_pch_nx (edge_def *e);

extern void gt_pch_nx (edge_def *e, gt_pointer_operator, void *);

/* Masks for edge.flags.  */

#define DEF_EDGE_FLAG(NAME,IDX) EDGE_##NAME = 1 << IDX ,

enum cfg_edge_flags {

#include "cfg-flags.def"

  LAST_CFG_EDGE_FLAG            /* this is only used for EDGE_ALL_FLAGS */

};

#undef DEF_EDGE_FLAG

/* Bit mask for all edge flags.  */

#define EDGE_ALL_FLAGS          ((LAST_CFG_EDGE_FLAG - 1) * 2 - 1)

/* The following four flags all indicate something special about an edge.

   Test the edge flags on EDGE_COMPLEX to detect all forms of "strange"

   control flow transfers.  */

#define EDGE_COMPLEX \

  (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_PRESERVE)

/* Counter summary from the last set of coverage counts read by

   profile.c.  */

extern const struct gcov_ctr_summary *profile_info;

/* Working set size statistics for a given percentage of the entire

   profile (sum_all from the counter summary).  */

typedef struct gcov_working_set_info

{

  /* Number of hot counters included in this working set.  */

  unsigned num_counters;

  /* Smallest counter included in this working set.  */

  gcov_type min_counter;

} gcov_working_set_t;

/* Structure to gather statistic about profile consistency, per pass.

   An array of this structure, indexed by pass static number, is allocated

   in passes.c.  The structure is defined here so that different CFG modes

   can do their book-keeping via CFG hooks.

   For every field[2], field[0] is the count before the pass runs, and

   field[1] is the post-pass count.  This allows us to monitor the effect

   of each individual pass on the profile consistency.

   This structure is not supposed to be used by anything other than passes.c

   and one CFG hook per CFG mode.  */

struct profile_record

{

  /* The number of basic blocks where sum(freq) of the block's predecessors

     doesn't match reasonably well with the incoming frequency.  */

  int num_mismatched_freq_in[2];

  /* Likewise for a basic block's successors.  */

  int num_mismatched_freq_out[2];

  /* The number of basic blocks where sum(count) of the block's predecessors

     doesn't match reasonably well with the incoming frequency.  */

  int num_mismatched_count_in[2];

  /* Likewise for a basic block's successors.  */

  int num_mismatched_count_out[2];

  /* A weighted cost of the run-time of the function body.  */

  gcov_type time[2];

  /* A weighted cost of the size of the function body.  */

  int size[2];

  /* True iff this pass actually was run.  */

  bool run;

};

/* Declared in cfgloop.h.  */

struct loop;

struct GTY(()) rtl_bb_info {

  /* The first insn of the block is embedded into bb->il.x.  */

  /* The last insn of the block.  */

  rtx end_;

  /* In CFGlayout mode points to insn notes/jumptables to be placed just before

     and after the block.   */

  rtx header_;

  rtx footer_;

};

struct GTY(()) gimple_bb_info {

  /* Sequence of statements in this block.  */

  gimple_seq seq;

  /* PHI nodes for this block.  */

  gimple_seq phi_nodes;

};

/* A basic block is a sequence of instructions with only one entry and

   only one exit.  If any one of the instructions are executed, they

   will all be executed, and in sequence from first to last.

   There may be COND_EXEC instructions in the basic block.  The

   COND_EXEC *instructions* will be executed -- but if the condition

   is false the conditionally executed *expressions* will of course

   not be executed.  We don't consider the conditionally executed

   expression (which might have side-effects) to be in a separate

   basic block because the program counter will always be at the same

   location after the COND_EXEC instruction, regardless of whether the

   condition is true or not.

   Basic blocks need not start with a label nor end with a jump insn.

   For example, a previous basic block may just "conditionally fall"

   into the succeeding basic block, and the last basic block need not

   end with a jump insn.  Block 0 is a descendant of the entry block.

   A basic block beginning with two labels cannot have notes between

   the labels.

   Data for jump tables are stored in jump_insns that occur in no

   basic block even though these insns can follow or precede insns in

   basic blocks.  */

/* Basic block information indexed by block number.  */

struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_def {

  /* The edges into and out of the block.  */

  vec<edge, va_gc> *preds;

  vec<edge, va_gc> *succs;

  /* Auxiliary info specific to a pass.  */

  PTR GTY ((skip (""))) aux;

  /* Innermost loop containing the block.  */

  struct loop *loop_father;

  /* The dominance and postdominance information node.  */

  struct et_node * GTY ((skip (""))) dom[2];

  /* Previous and next blocks in the chain.  */

  basic_block prev_bb;

  basic_block next_bb;

  union basic_block_il_dependent {

      struct gimple_bb_info GTY ((tag ("0"))) gimple;

      struct {

        rtx head_;

        struct rtl_bb_info * rtl;

      } GTY ((tag ("1"))) x;

    } GTY ((desc ("((%1.flags & BB_RTL) != 0)"))) il;

  /* Various flags.  See cfg-flags.def.  */

  int flags;

  /* The index of this block.  */

  int index;

  /* Expected number of executions: calculated in profile.c.  */

  gcov_type count;

  /* Expected frequency.  Normalized to be in range 0 to BB_FREQ_MAX.  */

  int frequency;

  /* The discriminator for this block.  The discriminator distinguishes

     among several basic blocks that share a common locus, allowing for

     more accurate sample-based profiling.  */

  int discriminator;

};

/* This ensures that struct gimple_bb_info is smaller than

   struct rtl_bb_info, so that inlining the former into basic_block_def

   is the better choice.  */

typedef int __assert_gimple_bb_smaller_rtl_bb

              [(int)sizeof(struct rtl_bb_info)

               - (int)sizeof (struct gimple_bb_info)];

#define BB_FREQ_MAX 10000

/* Masks for basic_block.flags.  */

#define DEF_BASIC_BLOCK_FLAG(NAME,IDX) BB_##NAME = 1 << IDX ,

enum cfg_bb_flags

{

#include "cfg-flags.def"

  LAST_CFG_BB_FLAG              /* this is only used for BB_ALL_FLAGS */

};

#undef DEF_BASIC_BLOCK_FLAG

/* Bit mask for all basic block flags.  */

#define BB_ALL_FLAGS            ((LAST_CFG_BB_FLAG - 1) * 2 - 1)

/* Bit mask for all basic block flags that must be preserved.  These are

   the bit masks that are *not* cleared by clear_bb_flags.  */

#define BB_FLAGS_TO_PRESERVE                                    \

  (BB_DISABLE_SCHEDULE | BB_RTL | BB_NON_LOCAL_GOTO_TARGET      \

   | BB_HOT_PARTITION | BB_COLD_PARTITION)

/* Dummy bitmask for convenience in the hot/cold partitioning code.  */

#define BB_UNPARTITIONED        0

/* Partitions, to be used when partitioning hot and cold basic blocks into

   separate sections.  */

#define BB_PARTITION(bb) ((bb)->flags & (BB_HOT_PARTITION|BB_COLD_PARTITION))

#define BB_SET_PARTITION(bb, part) do {                                 \

  basic_block bb_ = (bb);                                               \

  bb_->flags = ((bb_->flags & ~(BB_HOT_PARTITION|BB_COLD_PARTITION))    \

                | (part));                                              \

} while (0)

#define BB_COPY_PARTITION(dstbb, srcbb) \

  BB_SET_PARTITION (dstbb, BB_PARTITION (srcbb))

/* State of dominance information.  */

enum dom_state

{

  DOM_NONE,             /* Not computed at all.  */

  DOM_NO_FAST_QUERY,    /* The data is OK, but the fast query data are not usable.  */

  DOM_OK                /* Everything is ok.  */

};

/* What sort of profiling information we have.  */

enum profile_status_d

{

  PROFILE_ABSENT,

  PROFILE_GUESSED,

  PROFILE_READ,

  PROFILE_LAST  /* Last value, used by profile streaming.  */

};

/* A structure to group all the per-function control flow graph data.

   The x_* prefixing is necessary because otherwise references to the

   fields of this struct are interpreted as the defines for backward

   source compatibility following the definition of this struct.  */

struct GTY(()) control_flow_graph {

  /* Block pointers for the exit and entry of a function.

     These are always the head and tail of the basic block list.  */

  basic_block x_entry_block_ptr;

  basic_block x_exit_block_ptr;

  /* Index by basic block number, get basic block struct info.  */

  vec<basic_block, va_gc> *x_basic_block_info;

  /* Number of basic blocks in this flow graph.  */

  int x_n_basic_blocks;

  /* Number of edges in this flow graph.  */

  int x_n_edges;

  /* The first free basic block number.  */

  int x_last_basic_block;

  /* UIDs for LABEL_DECLs.  */

  int last_label_uid;

  /* Mapping of labels to their associated blocks.  At present

     only used for the gimple CFG.  */

  vec<basic_block, va_gc> *x_label_to_block_map;

  enum profile_status_d x_profile_status;

  /* Whether the dominators and the postdominators are available.  */

  enum dom_state x_dom_computed[2];

  /* Number of basic blocks in the dominance tree.  */

  unsigned x_n_bbs_in_dom_tree[2];

  /* Maximal number of entities in the single jumptable.  Used to estimate

     final flowgraph size.  */

  int max_jumptable_ents;

};

/* Defines for accessing the fields of the CFG structure for function FN.  */

#define ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)     ((FN)->cfg->x_entry_block_ptr)

#define EXIT_BLOCK_PTR_FOR_FUNCTION(FN)      ((FN)->cfg->x_exit_block_ptr)

#define basic_block_info_for_function(FN)    ((FN)->cfg->x_basic_block_info)

#define n_basic_blocks_for_function(FN)      ((FN)->cfg->x_n_basic_blocks)

#define n_edges_for_function(FN)             ((FN)->cfg->x_n_edges)

#define last_basic_block_for_function(FN)    ((FN)->cfg->x_last_basic_block)

#define label_to_block_map_for_function(FN)  ((FN)->cfg->x_label_to_block_map)

#define profile_status_for_function(FN)      ((FN)->cfg->x_profile_status)

#define BASIC_BLOCK_FOR_FUNCTION(FN,N) \

  ((*basic_block_info_for_function(FN))[(N)])

#define SET_BASIC_BLOCK_FOR_FUNCTION(FN,N,BB) \

  ((*basic_block_info_for_function(FN))[(N)] = (BB))

/* Defines for textual backward source compatibility.  */

#define ENTRY_BLOCK_PTR         (cfun->cfg->x_entry_block_ptr)

#define EXIT_BLOCK_PTR          (cfun->cfg->x_exit_block_ptr)

#define basic_block_info        (cfun->cfg->x_basic_block_info)

#define n_basic_blocks          (cfun->cfg->x_n_basic_blocks)

#define n_edges                 (cfun->cfg->x_n_edges)

#define last_basic_block        (cfun->cfg->x_last_basic_block)

#define label_to_block_map      (cfun->cfg->x_label_to_block_map)

#define profile_status          (cfun->cfg->x_profile_status)

#define BASIC_BLOCK(N)          ((*basic_block_info)[(N)])

#define SET_BASIC_BLOCK(N,BB)   ((*basic_block_info)[(N)] = (BB))

/* For iterating over basic blocks.  */

#define FOR_BB_BETWEEN(BB, FROM, TO, DIR) \

  for (BB = FROM; BB != TO; BB = BB->DIR)

#define FOR_EACH_BB_FN(BB, FN) \

  FOR_BB_BETWEEN (BB, (FN)->cfg->x_entry_block_ptr->next_bb, (FN)->cfg->x_exit_block_ptr, next_bb)

#define FOR_EACH_BB(BB) FOR_EACH_BB_FN (BB, cfun)

#define FOR_EACH_BB_REVERSE_FN(BB, FN) \

  FOR_BB_BETWEEN (BB, (FN)->cfg->x_exit_block_ptr->prev_bb, (FN)->cfg->x_entry_block_ptr, prev_bb)

#define FOR_EACH_BB_REVERSE(BB) FOR_EACH_BB_REVERSE_FN(BB, cfun)

/* For iterating over insns in basic block.  */

#define FOR_BB_INSNS(BB, INSN)                  \

  for ((INSN) = BB_HEAD (BB);                   \

       (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \

       (INSN) = NEXT_INSN (INSN))

/* For iterating over insns in basic block when we might remove the

   current insn.  */

#define FOR_BB_INSNS_SAFE(BB, INSN, CURR)                       \

  for ((INSN) = BB_HEAD (BB), (CURR) = (INSN) ? NEXT_INSN ((INSN)): NULL;       \

       (INSN) && (INSN) != NEXT_INSN (BB_END (BB));     \

       (INSN) = (CURR), (CURR) = (INSN) ? NEXT_INSN ((INSN)) : NULL)

#define FOR_BB_INSNS_REVERSE(BB, INSN)          \

  for ((INSN) = BB_END (BB);                    \

       (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \

       (INSN) = PREV_INSN (INSN))

#define FOR_BB_INSNS_REVERSE_SAFE(BB, INSN, CURR)       \

  for ((INSN) = BB_END (BB),(CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL;        \

       (INSN) && (INSN) != PREV_INSN (BB_HEAD (BB));    \

       (INSN) = (CURR), (CURR) = (INSN) ? PREV_INSN ((INSN)) : NULL)

/* Cycles through _all_ basic blocks, even the fake ones (entry and

   exit block).  */

#define FOR_ALL_BB(BB) \

  for (BB = ENTRY_BLOCK_PTR; BB; BB = BB->next_bb)

#define FOR_ALL_BB_FN(BB, FN) \

  for (BB = ENTRY_BLOCK_PTR_FOR_FUNCTION (FN); BB; BB = BB->next_bb)

/* Stuff for recording basic block info.  */

#define BB_HEAD(B)      (B)->il.x.head_

#define BB_END(B)       (B)->il.x.rtl->end_

#define BB_HEADER(B)    (B)->il.x.rtl->header_

#define BB_FOOTER(B)    (B)->il.x.rtl->footer_

/* Special block numbers [markers] for entry and exit.

   Neither of them is supposed to hold actual statements.  */

#define ENTRY_BLOCK (0)

#define EXIT_BLOCK (1)

/* The two blocks that are always in the cfg.  */

#define NUM_FIXED_BLOCKS (2)

#define set_block_for_insn(INSN, BB)  (BLOCK_FOR_INSN (INSN) = BB)

extern void compute_bb_for_insn (void);

extern unsigned int free_bb_for_insn (void);

extern void update_bb_for_insn (basic_block);

extern void insert_insn_on_edge (rtx, edge);

basic_block split_edge_and_insert (edge, rtx);

extern void commit_one_edge_insertion (edge e);

extern void commit_edge_insertions (void);

extern edge unchecked_make_edge (basic_block, basic_block, int);

extern edge cached_make_edge (sbitmap, basic_block, basic_block, int);

extern edge make_edge (basic_block, basic_block, int);

extern edge make_single_succ_edge (basic_block, basic_block, int);

extern void remove_edge_raw (edge);

extern void redirect_edge_succ (edge, basic_block);

extern edge redirect_edge_succ_nodup (edge, basic_block);

extern void redirect_edge_pred (edge, basic_block);

extern basic_block create_basic_block_structure (rtx, rtx, rtx, basic_block);

extern void clear_bb_flags (void);

extern void dump_bb_info (FILE *, basic_block, int, int, bool, bool);

extern void dump_edge_info (FILE *, edge, int, int);

extern void brief_dump_cfg (FILE *, int);

extern void clear_edges (void);

extern void scale_bbs_frequencies_int (basic_block *, int, int, int);

extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,

                                             gcov_type);

/* Structure to group all of the information to process IF-THEN and

   IF-THEN-ELSE blocks for the conditional execution support.  This

   needs to be in a public file in case the IFCVT macros call

   functions passing the ce_if_block data structure.  */

typedef struct ce_if_block

{

  basic_block test_bb;                  /* First test block.  */

  basic_block then_bb;                  /* THEN block.  */

  basic_block else_bb;                  /* ELSE block or NULL.  */

  basic_block join_bb;                  /* Join THEN/ELSE blocks.  */

  basic_block last_test_bb;             /* Last bb to hold && or || tests.  */

  int num_multiple_test_blocks;         /* # of && and || basic blocks.  */

  int num_and_and_blocks;               /* # of && blocks.  */

  int num_or_or_blocks;                 /* # of || blocks.  */

  int num_multiple_test_insns;          /* # of insns in && and || blocks.  */

  int and_and_p;                        /* Complex test is &&.  */

  int num_then_insns;                   /* # of insns in THEN block.  */

  int num_else_insns;                   /* # of insns in ELSE block.  */

  int pass;                             /* Pass number.  */

} ce_if_block_t;

/* This structure maintains an edge list vector.  */

/* FIXME: Make this a vec<edge>.  */

struct edge_list

{

  int num_edges;

  edge *index_to_edge;

};

/* The base value for branch probability notes and edge probabilities.  */

#define REG_BR_PROB_BASE  10000

/* This is the value which indicates no edge is present.  */

#define EDGE_INDEX_NO_EDGE      -1

/* EDGE_INDEX returns an integer index for an edge, or EDGE_INDEX_NO_EDGE

   if there is no edge between the 2 basic blocks.  */

#define EDGE_INDEX(el, pred, succ) (find_edge_index ((el), (pred), (succ)))

/* INDEX_EDGE_PRED_BB and INDEX_EDGE_SUCC_BB return a pointer to the basic

   block which is either the pred or succ end of the indexed edge.  */

#define INDEX_EDGE_PRED_BB(el, index)   ((el)->index_to_edge[(index)]->src)

#define INDEX_EDGE_SUCC_BB(el, index)   ((el)->index_to_edge[(index)]->dest)

/* INDEX_EDGE returns a pointer to the edge.  */

#define INDEX_EDGE(el, index)           ((el)->index_to_edge[(index)])

/* Number of edges in the compressed edge list.  */

#define NUM_EDGES(el)                   ((el)->num_edges)

/* BB is assumed to contain conditional jump.  Return the fallthru edge.  */

#define FALLTHRU_EDGE(bb)               (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \

                                         ? EDGE_SUCC ((bb), 0) : EDGE_SUCC ((bb), 1))

/* BB is assumed to contain conditional jump.  Return the branch edge.  */

#define BRANCH_EDGE(bb)                 (EDGE_SUCC ((bb), 0)->flags & EDGE_FALLTHRU \

                                         ? EDGE_SUCC ((bb), 1) : EDGE_SUCC ((bb), 0))

#define RDIV(X,Y) (((X) + (Y) / 2) / (Y))

/* Return expected execution frequency of the edge E.  */

#define EDGE_FREQUENCY(e)               RDIV ((e)->src->frequency * (e)->probability, \

                                              REG_BR_PROB_BASE)

/* Return nonzero if edge is critical.  */

#define EDGE_CRITICAL_P(e)              (EDGE_COUNT ((e)->src->succs) >= 2 \

                                         && EDGE_COUNT ((e)->dest->preds) >= 2)

#define EDGE_COUNT(ev)                  vec_safe_length (ev)

#define EDGE_I(ev,i)                    (*ev)[(i)]

#define EDGE_PRED(bb,i)                 (*(bb)->preds)[(i)]

#define EDGE_SUCC(bb,i)                 (*(bb)->succs)[(i)]

/* Returns true if BB has precisely one successor.  */

static inline bool

single_succ_p (const_basic_block bb)

{

  return EDGE_COUNT (bb->succs) == 1;

}

/* Returns true if BB has precisely one predecessor.  */

static inline bool

single_pred_p (const_basic_block bb)

{

  return EDGE_COUNT (bb->preds) == 1;

}

/* Returns the single successor edge of basic block BB.  Aborts if

   BB does not have exactly one successor.  */

static inline edge

single_succ_edge (const_basic_block bb)

{

  gcc_checking_assert (single_succ_p (bb));

  return EDGE_SUCC (bb, 0);

}

/* Returns the single predecessor edge of basic block BB.  Aborts

   if BB does not have exactly one predecessor.  */

static inline edge

single_pred_edge (const_basic_block bb)

{

  gcc_checking_assert (single_pred_p (bb));

  return EDGE_PRED (bb, 0);

}

/* Returns the single successor block of basic block BB.  Aborts

   if BB does not have exactly one successor.  */

static inline basic_block

single_succ (const_basic_block bb)

{

  return single_succ_edge (bb)->dest;

}

/* Returns the single predecessor block of basic block BB.  Aborts

   if BB does not have exactly one predecessor.*/

static inline basic_block

single_pred (const_basic_block bb)

{

  return single_pred_edge (bb)->src;

}

/* Iterator object for edges.  */

typedef struct {

  unsigned index;

  vec<edge, va_gc> **container;

} edge_iterator;

static inline vec<edge, va_gc> *

ei_container (edge_iterator i)

{

  gcc_checking_assert (i.container);

  return *i.container;

}

#define ei_start(iter) ei_start_1 (&(iter))

#define ei_last(iter) ei_last_1 (&(iter))

/* Return an iterator pointing to the start of an edge vector.  */

static inline edge_iterator

ei_start_1 (vec<edge, va_gc> **ev)

{

  edge_iterator i;

  i.index = 0;

  i.container = ev;

  return i;

}

/* Return an iterator pointing to the last element of an edge

   vector.  */

static inline edge_iterator

ei_last_1 (vec<edge, va_gc> **ev)

{

  edge_iterator i;

  i.index = EDGE_COUNT (*ev) - 1;

  i.container = ev;

  return i;

}

/* Is the iterator `i' at the end of the sequence?  */

static inline bool

ei_end_p (edge_iterator i)

{

  return (i.index == EDGE_COUNT (ei_container (i)));

}

/* Is the iterator `i' at one position before the end of the

   sequence?  */

static inline bool

ei_one_before_end_p (edge_iterator i)

{

  return (i.index + 1 == EDGE_COUNT (ei_container (i)));

}

/* Advance the iterator to the next element.  */

static inline void

ei_next (edge_iterator *i)

{

  gcc_checking_assert (i->index < EDGE_COUNT (ei_container (*i)));

  i->index++;

}

/* Move the iterator to the previous element.  */

static inline void

ei_prev (edge_iterator *i)

{

  gcc_checking_assert (i->index > 0);

  i->index--;

}

/* Return the edge pointed to by the iterator `i'.  */

static inline edge

ei_edge (edge_iterator i)

{

  return EDGE_I (ei_container (i), i.index);

}

/* Return an edge pointed to by the iterator.  Do it safely so that

   NULL is returned when the iterator is pointing at the end of the

   sequence.  */

static inline edge

ei_safe_edge (edge_iterator i)

{

  return !ei_end_p (i) ? ei_edge (i) : NULL;

}

/* Return 1 if we should continue to iterate.  Return 0 otherwise.

   *Edge P is set to the next edge if we are to continue to iterate

   and NULL otherwise.  */

static inline bool

ei_cond (edge_iterator ei, edge *p)

{

  if (!ei_end_p (ei))

    {

      *p = ei_edge (ei);

      return 1;

    }

  else

    {

      *p = NULL;

      return 0;

    }

}

/* This macro serves as a convenient way to iterate each edge in a

   vector of predecessor or successor edges.  It must not be used when

   an element might be removed during the traversal, otherwise

   elements will be missed.  Instead, use a for-loop like that shown

   in the following pseudo-code:

   FOR (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )

     {

        IF (e != taken_edge)

          remove_edge (e);

        ELSE

          ei_next (&ei);

     }

*/

#define FOR_EACH_EDGE(EDGE,ITER,EDGE_VEC)       \

  for ((ITER) = ei_start ((EDGE_VEC));          \

       ei_cond ((ITER), &(EDGE));               \

       ei_next (&(ITER)))

#define CLEANUP_EXPENSIVE       1       /* Do relatively expensive optimizations

                                           except for edge forwarding */

#define CLEANUP_CROSSJUMP       2       /* Do crossjumping.  */

#define CLEANUP_POST_REGSTACK   4       /* We run after reg-stack and need

                                           to care REG_DEAD notes.  */

#define CLEANUP_THREADING       8       /* Do jump threading.  */

#define CLEANUP_NO_INSN_DEL     16      /* Do not try to delete trivially dead

                                           insns.  */

#define CLEANUP_CFGLAYOUT       32      /* Do cleanup in cfglayout mode.  */

#define CLEANUP_CFG_CHANGED     64      /* The caller changed the CFG.  */

/* In cfganal.c */

extern void bitmap_intersection_of_succs (sbitmap, sbitmap *, basic_block);

extern void bitmap_intersection_of_preds (sbitmap, sbitmap *, basic_block);

extern void bitmap_union_of_succs (sbitmap, sbitmap *, basic_block);

extern void bitmap_union_of_preds (sbitmap, sbitmap *, basic_block);

/* In lcm.c */

extern struct edge_list *pre_edge_lcm (int, sbitmap *, sbitmap *,

                                       sbitmap *, sbitmap *, sbitmap **,

                                       sbitmap **);

extern struct edge_list *pre_edge_rev_lcm (int, sbitmap *,

                                           sbitmap *, sbitmap *,

                                           sbitmap *, sbitmap **,

                                           sbitmap **);

extern void compute_available (sbitmap *, sbitmap *, sbitmap *, sbitmap *);

/* In predict.c */

extern bool maybe_hot_bb_p (struct function *, const_basic_block);

extern bool maybe_hot_edge_p (edge);

extern bool probably_never_executed_bb_p (struct function *, const_basic_block);

extern bool optimize_bb_for_size_p (const_basic_block);

extern bool optimize_bb_for_speed_p (const_basic_block);

extern bool optimize_edge_for_size_p (edge);