2009-05-21 Richard Guenther <rguenther@suse.de>

[official-gcc.git] / gcc / ipa-inline.c

/* Inlining decision heuristics.
   Copyright (C) 2003, 2004, 2007, 2008, 2009 Free Software Foundation, Inc.
   Contributed by Jan Hubicka

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/>.  */

/*  Inlining decision heuristics

    We separate inlining decisions from the inliner itself and store it
    inside callgraph as so called inline plan.  Refer to cgraph.c
    documentation about particular representation of inline plans in the
    callgraph.

    There are three major parts of this file:

    cgraph_mark_inline implementation

      This function allows to mark given call inline and performs necessary
      modifications of cgraph (production of the clones and updating overall
      statistics)

    inlining heuristics limits

      These functions allow to check that particular inlining is allowed
      by the limits specified by user (allowed function growth, overall unit
      growth and so on).

    inlining heuristics

      This is implementation of IPA pass aiming to get as much of benefit
      from inlining obeying the limits checked above.

      The implementation of particular heuristics is separated from
      the rest of code to make it easier to replace it with more complicated
      implementation in the future.  The rest of inlining code acts as a
      library aimed to modify the callgraph and verify that the parameters
      on code size growth fits.

      To mark given call inline, use cgraph_mark_inline function, the
      verification is performed by cgraph_default_inline_p and
      cgraph_check_inline_limits.

      The heuristics implements simple knapsack style algorithm ordering
      all functions by their "profitability" (estimated by code size growth)
      and inlining them in priority order.

      cgraph_decide_inlining implements heuristics taking whole callgraph
      into account, while cgraph_decide_inlining_incrementally considers
      only one function at a time and is used by early inliner.

   The inliner itself is split into several passes:

   pass_inline_parameters

     This pass computes local properties of functions that are used by inliner:
     estimated function body size, whether function is inlinable at all and
     stack frame consumption.

     Before executing any of inliner passes, this local pass has to be applied
     to each function in the callgraph (ie run as subpass of some earlier
     IPA pass).  The results are made out of date by any optimization applied
     on the function body.

   pass_early_inlining

     Simple local inlining pass inlining callees into current function.  This
     pass makes no global whole compilation unit analysis and this when allowed
     to do inlining expanding code size it might result in unbounded growth of
     whole unit.

     The pass is run during conversion into SSA form.  Only functions already
     converted into SSA form are inlined, so the conversion must happen in
     topological order on the callgraph (that is maintained by pass manager).
     The functions after inlining are early optimized so the early inliner sees
     unoptimized function itself, but all considered callees are already
     optimized allowing it to unfold abstraction penalty on C++ effectively and
     cheaply.

   pass_ipa_early_inlining

     With profiling, the early inlining is also necessary to reduce
     instrumentation costs on program with high abstraction penalty (doing
     many redundant calls).  This can't happen in parallel with early
     optimization and profile instrumentation, because we would end up
     re-instrumenting already instrumented function bodies we brought in via
     inlining.

     To avoid this, this pass is executed as IPA pass before profiling.  It is
     simple wrapper to pass_early_inlining and ensures first inlining.

   pass_ipa_inline

     This is the main pass implementing simple greedy algorithm to do inlining
     of small functions that results in overall growth of compilation unit and
     inlining of functions called once.  The pass compute just so called inline
     plan (representation of inlining to be done in callgraph) and unlike early
     inlining it is not performing the inlining itself.

   pass_apply_inline

     This pass performs actual inlining according to pass_ipa_inline on given
     function.  Possible the function body before inlining is saved when it is
     needed for further inlining later.
 */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "tree-inline.h"
#include "langhooks.h"
#include "flags.h"
#include "cgraph.h"
#include "diagnostic.h"
#include "timevar.h"
#include "params.h"
#include "fibheap.h"
#include "intl.h"
#include "tree-pass.h"
#include "hashtab.h"
#include "coverage.h"
#include "ggc.h"
#include "tree-flow.h"
#include "rtl.h"
#include "ipa-prop.h"

/* Mode incremental inliner operate on:

   In ALWAYS_INLINE only functions marked
   always_inline are inlined.  This mode is used after detecting cycle during
   flattening.

   In SIZE mode, only functions that reduce function body size after inlining
   are inlined, this is used during early inlining.

   in ALL mode, everything is inlined.  This is used during flattening.  */
enum inlining_mode {
  INLINE_NONE = 0,
  INLINE_ALWAYS_INLINE,
  INLINE_SIZE_NORECURSIVE,
  INLINE_SIZE,
  INLINE_ALL
};
static bool
cgraph_decide_inlining_incrementally (struct cgraph_node *, enum inlining_mode,
                                      int);


/* Statistics we collect about inlining algorithm.  */
static int ncalls_inlined;
static int nfunctions_inlined;
static int overall_insns;
static gcov_type max_count;

/* Holders of ipa cgraph hooks: */
static struct cgraph_node_hook_list *function_insertion_hook_holder;

static inline struct inline_summary *
inline_summary (struct cgraph_node *node)
{
  return &node->local.inline_summary;
}

/* Estimate size of the function after inlining WHAT into TO.  */

static int
cgraph_estimate_size_after_inlining (int times, struct cgraph_node *to,
                                     struct cgraph_node *what)
{
  int size;
  tree fndecl = what->decl, arg;
  int call_insns = PARAM_VALUE (PARAM_INLINE_CALL_COST);

  for (arg = DECL_ARGUMENTS (fndecl); arg; arg = TREE_CHAIN (arg))
    call_insns += estimate_move_cost (TREE_TYPE (arg));
  size = (what->global.insns - call_insns) * times + to->global.insns;
  gcc_assert (size >= 0);
  return size;
}

/* E is expected to be an edge being inlined.  Clone destination node of
   the edge and redirect it to the new clone.
   DUPLICATE is used for bookkeeping on whether we are actually creating new
   clones or re-using node originally representing out-of-line function call.
   */
void
cgraph_clone_inlined_nodes (struct cgraph_edge *e, bool duplicate,
                            bool update_original)
{
  HOST_WIDE_INT peak;

  if (duplicate)
    {
      /* We may eliminate the need for out-of-line copy to be output.
         In that case just go ahead and re-use it.  */
      if (!e->callee->callers->next_caller
          && !e->callee->needed
          && !cgraph_new_nodes)
        {
          gcc_assert (!e->callee->global.inlined_to);
          if (e->callee->analyzed)
            overall_insns -= e->callee->global.insns, nfunctions_inlined++;
          duplicate = false;
        }
      else
        {
          struct cgraph_node *n;
          n = cgraph_clone_node (e->callee, e->count, e->frequency, e->loop_nest, 
                                 update_original);
          cgraph_redirect_edge_callee (e, n);
        }
    }

  if (e->caller->global.inlined_to)
    e->callee->global.inlined_to = e->caller->global.inlined_to;
  else
    e->callee->global.inlined_to = e->caller;
  e->callee->global.stack_frame_offset
    = e->caller->global.stack_frame_offset
      + inline_summary (e->caller)->estimated_self_stack_size;
  peak = e->callee->global.stack_frame_offset
      + inline_summary (e->callee)->estimated_self_stack_size;
  if (e->callee->global.inlined_to->global.estimated_stack_size < peak)
    e->callee->global.inlined_to->global.estimated_stack_size = peak;

  /* Recursively clone all bodies.  */
  for (e = e->callee->callees; e; e = e->next_callee)
    if (!e->inline_failed)
      cgraph_clone_inlined_nodes (e, duplicate, update_original);
}

/* Mark edge E as inlined and update callgraph accordingly.  UPDATE_ORIGINAL
   specify whether profile of original function should be updated.  If any new
   indirect edges are discovered in the process, add them to NEW_EDGES, unless
   it is NULL.  Return true iff any new callgraph edges were discovered as a
   result of inlining.  */

static bool
cgraph_mark_inline_edge (struct cgraph_edge *e, bool update_original,
                         VEC (cgraph_edge_p, heap) **new_edges)
{
  int old_insns = 0, new_insns = 0;
  struct cgraph_node *to = NULL, *what;
  struct cgraph_edge *curr = e;

  gcc_assert (e->inline_failed);
  e->inline_failed = CIF_OK;

  if (!e->callee->global.inlined)
    DECL_POSSIBLY_INLINED (e->callee->decl) = true;
  e->callee->global.inlined = true;

  cgraph_clone_inlined_nodes (e, true, update_original);

  what = e->callee;

  /* Now update size of caller and all functions caller is inlined into.  */
  for (;e && !e->inline_failed; e = e->caller->callers)
    {
      old_insns = e->caller->global.insns;
      new_insns = cgraph_estimate_size_after_inlining (1, e->caller,
                                                       what);
      gcc_assert (new_insns >= 0);
      to = e->caller;
      to->global.insns = new_insns;
    }
  gcc_assert (what->global.inlined_to == to);
  if (new_insns > old_insns)
    overall_insns += new_insns - old_insns;
  ncalls_inlined++;

  if (flag_indirect_inlining)
    return ipa_propagate_indirect_call_infos (curr, new_edges);
  else
    return false;
}

/* Mark all calls of EDGE->CALLEE inlined into EDGE->CALLER.
   Return following unredirected edge in the list of callers
   of EDGE->CALLEE  */

static struct cgraph_edge *
cgraph_mark_inline (struct cgraph_edge *edge)
{
  struct cgraph_node *to = edge->caller;
  struct cgraph_node *what = edge->callee;
  struct cgraph_edge *e, *next;

  gcc_assert (!gimple_call_cannot_inline_p (edge->call_stmt));
  /* Look for all calls, mark them inline and clone recursively
     all inlined functions.  */
  for (e = what->callers; e; e = next)
    {
      next = e->next_caller;
      if (e->caller == to && e->inline_failed)
        {
          cgraph_mark_inline_edge (e, true, NULL);
          if (e == edge)
            edge = next;
        }
    }

  return edge;
}

/* Estimate the growth caused by inlining NODE into all callees.  */

static int
cgraph_estimate_growth (struct cgraph_node *node)
{
  int growth = 0;
  struct cgraph_edge *e;
  bool self_recursive = false;

  if (node->global.estimated_growth != INT_MIN)
    return node->global.estimated_growth;

  for (e = node->callers; e; e = e->next_caller)
    {
      if (e->caller == node)
        self_recursive = true;
      if (e->inline_failed)
        growth += (cgraph_estimate_size_after_inlining (1, e->caller, node)
                   - e->caller->global.insns);
    }

  /* ??? Wrong for non-trivially self recursive functions or cases where
     we decide to not inline for different reasons, but it is not big deal
     as in that case we will keep the body around, but we will also avoid
     some inlining.  */
  if (!node->needed && !DECL_EXTERNAL (node->decl) && !self_recursive)
    growth -= node->global.insns;

  node->global.estimated_growth = growth;
  return growth;
}

/* Return false when inlining WHAT into TO is not good idea
   as it would cause too large growth of function bodies.  
   When ONE_ONLY is true, assume that only one call site is going
   to be inlined, otherwise figure out how many call sites in
   TO calls WHAT and verify that all can be inlined.
   */

static bool
cgraph_check_inline_limits (struct cgraph_node *to, struct cgraph_node *what,
                            cgraph_inline_failed_t *reason, bool one_only)
{
  int times = 0;
  struct cgraph_edge *e;
  int newsize;
  int limit;
  HOST_WIDE_INT stack_size_limit, inlined_stack;

  if (one_only)
    times = 1;
  else
    for (e = to->callees; e; e = e->next_callee)
      if (e->callee == what)
        times++;

  if (to->global.inlined_to)
    to = to->global.inlined_to;

  /* When inlining large function body called once into small function,
     take the inlined function as base for limiting the growth.  */
  if (inline_summary (to)->self_insns > inline_summary(what)->self_insns)
    limit = inline_summary (to)->self_insns;
  else
    limit = inline_summary (what)->self_insns;

  limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100;

  /* Check the size after inlining against the function limits.  But allow
     the function to shrink if it went over the limits by forced inlining.  */
  newsize = cgraph_estimate_size_after_inlining (times, to, what);
  if (newsize >= to->global.insns
      && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS)
      && newsize > limit)
    {
      if (reason)
        *reason = CIF_LARGE_FUNCTION_GROWTH_LIMIT;
      return false;
    }

  stack_size_limit = inline_summary (to)->estimated_self_stack_size;

  stack_size_limit += stack_size_limit * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100;

  inlined_stack = (to->global.stack_frame_offset
                   + inline_summary (to)->estimated_self_stack_size
                   + what->global.estimated_stack_size);
  if (inlined_stack  > stack_size_limit
      && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME))
    {
      if (reason)
        *reason = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT;
      return false;
    }
  return true;
}

/* Return true when function N is small enough to be inlined.  */

static bool
cgraph_default_inline_p (struct cgraph_node *n, cgraph_inline_failed_t *reason)
{
  tree decl = n->decl;

  if (!flag_inline_small_functions && !DECL_DECLARED_INLINE_P (decl))
    {
      if (reason)
        *reason = CIF_FUNCTION_NOT_INLINE_CANDIDATE;
      return false;
    }

  if (!n->analyzed)
    {
      if (reason)
        *reason = CIF_BODY_NOT_AVAILABLE;
      return false;
    }

  if (DECL_DECLARED_INLINE_P (decl))
    {
      if (n->global.insns >= MAX_INLINE_INSNS_SINGLE)
        {
          if (reason)
            *reason = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT;
          return false;
        }
    }
  else
    {
      if (n->global.insns >= MAX_INLINE_INSNS_AUTO)
        {
          if (reason)
            *reason = CIF_MAX_INLINE_INSNS_AUTO_LIMIT;
          return false;
        }
    }

  return true;
}

/* Return true when inlining WHAT would create recursive inlining.
   We call recursive inlining all cases where same function appears more than
   once in the single recursion nest path in the inline graph.  */

static bool
cgraph_recursive_inlining_p (struct cgraph_node *to,
                             struct cgraph_node *what,
                             cgraph_inline_failed_t *reason)
{
  bool recursive;
  if (to->global.inlined_to)
    recursive = what->decl == to->global.inlined_to->decl;
  else
    recursive = what->decl == to->decl;
  /* Marking recursive function inline has sane semantic and thus we should
     not warn on it.  */
  if (recursive && reason)
    *reason = (what->local.disregard_inline_limits
               ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
  return recursive;
}

/* A cost model driving the inlining heuristics in a way so the edges with
   smallest badness are inlined first.  After each inlining is performed
   the costs of all caller edges of nodes affected are recomputed so the
   metrics may accurately depend on values such as number of inlinable callers
   of the function or function body size.  */

static int
cgraph_edge_badness (struct cgraph_edge *edge)
{
  int badness;
  int growth =
    cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);

  growth -= edge->caller->global.insns;

  /* Always prefer inlining saving code size.  */
  if (growth <= 0)
    badness = INT_MIN - growth;

  /* When profiling is available, base priorities -(#calls / growth).
     So we optimize for overall number of "executed" inlined calls.  */
  else if (max_count)
    badness = ((int)((double)edge->count * INT_MIN / max_count)) / growth;

  /* When function local profile is available, base priorities on
     growth / frequency, so we optimize for overall frequency of inlined
     calls.  This is not too accurate since while the call might be frequent
     within function, the function itself is infrequent.

     Other objective to optimize for is number of different calls inlined.
     We add the estimated growth after inlining all functions to bias the
     priorities slightly in this direction (so fewer times called functions
     of the same size gets priority).  */
  else if (flag_guess_branch_prob)
    {
      int div = edge->frequency * 100 / CGRAPH_FREQ_BASE;
      int growth =
        cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
      growth -= edge->caller->global.insns;
      badness = growth * 256;

      /* Decrease badness if call is nested.  */
      /* Compress the range so we don't overflow.  */
      if (div > 256)
        div = 256 + ceil_log2 (div) - 8;
      if (div < 1)
        div = 1;
      if (badness > 0)
        badness /= div;
      badness += cgraph_estimate_growth (edge->callee);
    }
  /* When function local profile is not available or it does not give
     useful information (ie frequency is zero), base the cost on
     loop nest and overall size growth, so we optimize for overall number
     of functions fully inlined in program.  */
  else
    {
      int nest = MIN (edge->loop_nest, 8);
      badness = cgraph_estimate_growth (edge->callee) * 256;

      /* Decrease badness if call is nested.  */
      if (badness > 0)    
        badness >>= nest;
      else
        {
          badness <<= nest;
        }
    }
  /* Make recursive inlining happen always after other inlining is done.  */
  if (cgraph_recursive_inlining_p (edge->caller, edge->callee, NULL))
    return badness + 1;
  else
    return badness;
}

/* Recompute heap nodes for each of caller edge.  */

static void
update_caller_keys (fibheap_t heap, struct cgraph_node *node,
                    bitmap updated_nodes)
{
  struct cgraph_edge *edge;
  cgraph_inline_failed_t failed_reason;

  if (!node->local.inlinable || node->local.disregard_inline_limits
      || node->global.inlined_to)
    return;
  if (bitmap_bit_p (updated_nodes, node->uid))
    return;
  bitmap_set_bit (updated_nodes, node->uid);
  node->global.estimated_growth = INT_MIN;

  if (!node->local.inlinable)
    return;
  /* Prune out edges we won't inline into anymore.  */
  if (!cgraph_default_inline_p (node, &failed_reason))
    {
      for (edge = node->callers; edge; edge = edge->next_caller)
        if (edge->aux)
          {
            fibheap_delete_node (heap, (fibnode_t) edge->aux);
            edge->aux = NULL;
            if (edge->inline_failed)
              edge->inline_failed = failed_reason;
          }
      return;
    }

  for (edge = node->callers; edge; edge = edge->next_caller)
    if (edge->inline_failed)
      {
        int badness = cgraph_edge_badness (edge);
        if (edge->aux)
          {
            fibnode_t n = (fibnode_t) edge->aux;
            gcc_assert (n->data == edge);
            if (n->key == badness)
              continue;

            /* fibheap_replace_key only increase the keys.  */
            if (fibheap_replace_key (heap, n, badness))
              continue;
            fibheap_delete_node (heap, (fibnode_t) edge->aux);
          }
        edge->aux = fibheap_insert (heap, badness, edge);
      }
}

/* Recompute heap nodes for each of caller edges of each of callees.  */

static void
update_callee_keys (fibheap_t heap, struct cgraph_node *node,
                    bitmap updated_nodes)
{
  struct cgraph_edge *e;
  node->global.estimated_growth = INT_MIN;

  for (e = node->callees; e; e = e->next_callee)
    if (e->inline_failed)
      update_caller_keys (heap, e->callee, updated_nodes);
    else if (!e->inline_failed)
      update_callee_keys (heap, e->callee, updated_nodes);
}

/* Enqueue all recursive calls from NODE into priority queue depending on
   how likely we want to recursively inline the call.  */

static void
lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where,
                        fibheap_t heap)
{
  static int priority;
  struct cgraph_edge *e;
  for (e = where->callees; e; e = e->next_callee)
    if (e->callee == node)
      {
        /* When profile feedback is available, prioritize by expected number
           of calls.  Without profile feedback we maintain simple queue
           to order candidates via recursive depths.  */
        fibheap_insert (heap,
                        !max_count ? priority++
                        : -(e->count / ((max_count + (1<<24) - 1) / (1<<24))),
                        e);
      }
  for (e = where->callees; e; e = e->next_callee)
    if (!e->inline_failed)
      lookup_recursive_calls (node, e->callee, heap);
}

/* Decide on recursive inlining: in the case function has recursive calls,
   inline until body size reaches given argument.  If any new indirect edges
   are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES
   is NULL.  */

static bool
cgraph_decide_recursive_inlining (struct cgraph_node *node,
                                  VEC (cgraph_edge_p, heap) **new_edges)
{
  int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO);
  int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO);
  int probability = PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY);
  fibheap_t heap;
  struct cgraph_edge *e;
  struct cgraph_node *master_clone, *next;
  int depth = 0;
  int n = 0;

  if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION (node->decl))
      || (!flag_inline_functions && !DECL_DECLARED_INLINE_P (node->decl)))
    return false;

  if (DECL_DECLARED_INLINE_P (node->decl))
    {
      limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE);
      max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH);
    }

  /* Make sure that function is small enough to be considered for inlining.  */
  if (!max_depth
      || cgraph_estimate_size_after_inlining (1, node, node)  >= limit)
    return false;
  heap = fibheap_new ();
  lookup_recursive_calls (node, node, heap);
  if (fibheap_empty (heap))
    {
      fibheap_delete (heap);
      return false;
    }

  if (dump_file)
    fprintf (dump_file, 
             "  Performing recursive inlining on %s\n",
             cgraph_node_name (node));

  /* We need original clone to copy around.  */
  master_clone = cgraph_clone_node (node, node->count, CGRAPH_FREQ_BASE, 1, false);
  master_clone->needed = true;
  for (e = master_clone->callees; e; e = e->next_callee)
    if (!e->inline_failed)
      cgraph_clone_inlined_nodes (e, true, false);

  /* Do the inlining and update list of recursive call during process.  */
  while (!fibheap_empty (heap)
         && (cgraph_estimate_size_after_inlining (1, node, master_clone)
             <= limit))
    {
      struct cgraph_edge *curr
        = (struct cgraph_edge *) fibheap_extract_min (heap);
      struct cgraph_node *cnode;

      depth = 1;
      for (cnode = curr->caller;
           cnode->global.inlined_to; cnode = cnode->callers->caller)
        if (node->decl == curr->callee->decl)
          depth++;
      if (depth > max_depth)
        {
          if (dump_file)
            fprintf (dump_file, 
                     "   maximal depth reached\n");
          continue;
        }

      if (max_count)
        {
          if (!cgraph_maybe_hot_edge_p (curr))
            {
              if (dump_file)
                fprintf (dump_file, "   Not inlining cold call\n");
              continue;
            }
          if (curr->count * 100 / node->count < probability)
            {
              if (dump_file)
                fprintf (dump_file, 
                         "   Probability of edge is too small\n");
              continue;
            }
        }

      if (dump_file)
        {
          fprintf (dump_file, 
                   "   Inlining call of depth %i", depth);
          if (node->count)
            {
              fprintf (dump_file, " called approx. %.2f times per call",
                       (double)curr->count / node->count);
            }
          fprintf (dump_file, "\n");
        }
      cgraph_redirect_edge_callee (curr, master_clone);
      cgraph_mark_inline_edge (curr, false, new_edges);
      lookup_recursive_calls (node, curr->callee, heap);
      n++;
    }
  if (!fibheap_empty (heap) && dump_file)
    fprintf (dump_file, "    Recursive inlining growth limit met.\n");

  fibheap_delete (heap);
  if (dump_file)
    fprintf (dump_file, 
             "\n   Inlined %i times, body grown from %i to %i insns\n", n,
             master_clone->global.insns, node->global.insns);

  /* Remove master clone we used for inlining.  We rely that clones inlined
     into master clone gets queued just before master clone so we don't
     need recursion.  */
  for (node = cgraph_nodes; node != master_clone;
       node = next)
    {
      next = node->next;
      if (node->global.inlined_to == master_clone)
        cgraph_remove_node (node);
    }
  cgraph_remove_node (master_clone);
  /* FIXME: Recursive inlining actually reduces number of calls of the
     function.  At this place we should probably walk the function and
     inline clones and compensate the counts accordingly.  This probably
     doesn't matter much in practice.  */
  return n > 0;
}

/* Set inline_failed for all callers of given function to REASON.  */

static void
cgraph_set_inline_failed (struct cgraph_node *node,
                          cgraph_inline_failed_t reason)
{
  struct cgraph_edge *e;

  if (dump_file)
    fprintf (dump_file, "Inlining failed: %s\n",
             cgraph_inline_failed_string (reason));
  for (e = node->callers; e; e = e->next_caller)
    if (e->inline_failed)
      e->inline_failed = reason;
}

/* Given whole compilation unit estimate of INSNS, compute how large we can
   allow the unit to grow.  */
static int
compute_max_insns (int insns)
{
  int max_insns = insns;
  if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
    max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);

  return ((HOST_WIDEST_INT) max_insns
          * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100);
}

/* Compute badness of all edges in NEW_EDGES and add them to the HEAP.  */
static void
add_new_edges_to_heap (fibheap_t heap, VEC (cgraph_edge_p, heap) *new_edges)
{
  while (VEC_length (cgraph_edge_p, new_edges) > 0)
    {
      struct cgraph_edge *edge = VEC_pop (cgraph_edge_p, new_edges);

      gcc_assert (!edge->aux);
      edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge), edge);
    }
}


/* We use greedy algorithm for inlining of small functions:
   All inline candidates are put into prioritized heap based on estimated
   growth of the overall number of instructions and then update the estimates.

   INLINED and INLINED_CALEES are just pointers to arrays large enough
   to be passed to cgraph_inlined_into and cgraph_inlined_callees.  */

static void
cgraph_decide_inlining_of_small_functions (void)
{
  struct cgraph_node *node;
  struct cgraph_edge *edge;
  cgraph_inline_failed_t failed_reason;
  fibheap_t heap = fibheap_new ();
  bitmap updated_nodes = BITMAP_ALLOC (NULL);
  int min_insns, max_insns;
  VEC (cgraph_edge_p, heap) *new_indirect_edges = NULL;

  if (flag_indirect_inlining)
    new_indirect_edges = VEC_alloc (cgraph_edge_p, heap, 8);

  if (dump_file)
    fprintf (dump_file, "\nDeciding on smaller functions:\n");

  /* Put all inline candidates into the heap.  */

  for (node = cgraph_nodes; node; node = node->next)
    {
      if (!node->local.inlinable || !node->callers
          || node->local.disregard_inline_limits)
        continue;
      if (dump_file)
        fprintf (dump_file, "Considering inline candidate %s.\n", cgraph_node_name (node));

      node->global.estimated_growth = INT_MIN;
      if (!cgraph_default_inline_p (node, &failed_reason))
        {
          cgraph_set_inline_failed (node, failed_reason);
          continue;
        }

      for (edge = node->callers; edge; edge = edge->next_caller)
        if (edge->inline_failed)
          {
            gcc_assert (!edge->aux);
            edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge), edge);
          }
    }

  max_insns = compute_max_insns (overall_insns);
  min_insns = overall_insns;

  while (overall_insns <= max_insns
         && (edge = (struct cgraph_edge *) fibheap_extract_min (heap)))
    {
      int old_insns = overall_insns;
      struct cgraph_node *where;
      int growth =
        cgraph_estimate_size_after_inlining (1, edge->caller, edge->callee);
      cgraph_inline_failed_t not_good = CIF_OK;

      growth -= edge->caller->global.insns;

      if (dump_file)
        {
          fprintf (dump_file, 
                   "\nConsidering %s with %i insns\n",
                   cgraph_node_name (edge->callee),
                   edge->callee->global.insns);
          fprintf (dump_file, 
                   " to be inlined into %s in %s:%i\n"
                   " Estimated growth after inlined into all callees is %+i insns.\n"
                   " Estimated badness is %i, frequency %.2f.\n",
                   cgraph_node_name (edge->caller),
                   gimple_filename ((const_gimple) edge->call_stmt),
                   gimple_lineno ((const_gimple) edge->call_stmt),
                   cgraph_estimate_growth (edge->callee),
                   cgraph_edge_badness (edge),
                   edge->frequency / (double)CGRAPH_FREQ_BASE);
          if (edge->count)
            fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", edge->count);
        }
      gcc_assert (edge->aux);
      edge->aux = NULL;
      if (!edge->inline_failed)
        continue;

      /* When not having profile info ready we don't weight by any way the
         position of call in procedure itself.  This means if call of
         function A from function B seems profitable to inline, the recursive
         call of function A in inline copy of A in B will look profitable too
         and we end up inlining until reaching maximal function growth.  This
         is not good idea so prohibit the recursive inlining.

         ??? When the frequencies are taken into account we might not need this
         restriction.

         We need to be cureful here, in some testcases, e.g. directivec.c in
         libcpp, we can estimate self recursive function to have negative growth
         for inlining completely.
         */
      if (!edge->count)
        {
          where = edge->caller;
          while (where->global.inlined_to)
            {
              if (where->decl == edge->callee->decl)
                break;
              where = where->callers->caller;
            }
          if (where->global.inlined_to)
            {
              edge->inline_failed
                = (edge->callee->local.disregard_inline_limits
                   ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
              if (dump_file)
                fprintf (dump_file, " inline_failed:Recursive inlining performed only for function itself.\n");
              continue;
            }
        }

      if (!cgraph_maybe_hot_edge_p (edge))
        not_good = CIF_UNLIKELY_CALL;
      if (!flag_inline_functions
          && !DECL_DECLARED_INLINE_P (edge->callee->decl))
        not_good = CIF_NOT_DECLARED_INLINED;
      if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION(edge->caller->decl)))
        not_good = CIF_OPTIMIZING_FOR_SIZE;
      if (not_good && growth > 0 && cgraph_estimate_growth (edge->callee) > 0)
        {
          if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
                                            &edge->inline_failed))
            {
              edge->inline_failed = not_good;
              if (dump_file)
                fprintf (dump_file, " inline_failed:%s.\n",
                         cgraph_inline_failed_string (edge->inline_failed));
            }
          continue;
        }
      if (!cgraph_default_inline_p (edge->callee, &edge->inline_failed))
        {
          if (!cgraph_recursive_inlining_p (edge->caller, edge->callee,
                                            &edge->inline_failed))
            {
              if (dump_file)
                fprintf (dump_file, " inline_failed:%s.\n",
                         cgraph_inline_failed_string (edge->inline_failed));
            }
          continue;
        }
      if (!tree_can_inline_p (edge->caller->decl, edge->callee->decl))
        {
          gimple_call_set_cannot_inline (edge->call_stmt, true);
          edge->inline_failed = CIF_TARGET_OPTION_MISMATCH;
          if (dump_file)
            fprintf (dump_file, " inline_failed:%s.\n",
                     cgraph_inline_failed_string (edge->inline_failed));
          continue;
        }
      if (cgraph_recursive_inlining_p (edge->caller, edge->callee,
                                       &edge->inline_failed))
        {
          where = edge->caller;
          if (where->global.inlined_to)
            where = where->global.inlined_to;
          if (!cgraph_decide_recursive_inlining (where,
                                                 flag_indirect_inlining
                                                 ? &new_indirect_edges : NULL))
            continue;
          if (flag_indirect_inlining)
            add_new_edges_to_heap (heap, new_indirect_edges);
          update_callee_keys (heap, where, updated_nodes);
        }
      else
        {
          struct cgraph_node *callee;
          if (gimple_call_cannot_inline_p (edge->call_stmt)
              || !cgraph_check_inline_limits (edge->caller, edge->callee,
                                              &edge->inline_failed, true))
            {
              if (dump_file)
                fprintf (dump_file, " Not inlining into %s:%s.\n",
                         cgraph_node_name (edge->caller),
                         cgraph_inline_failed_string (edge->inline_failed));
              continue;
            }
          callee = edge->callee;
          cgraph_mark_inline_edge (edge, true, &new_indirect_edges);
          if (flag_indirect_inlining)
            add_new_edges_to_heap (heap, new_indirect_edges);

          update_callee_keys (heap, callee, updated_nodes);
        }
      where = edge->caller;
      if (where->global.inlined_to)
        where = where->global.inlined_to;

      /* Our profitability metric can depend on local properties
         such as number of inlinable calls and size of the function body.
         After inlining these properties might change for the function we
         inlined into (since it's body size changed) and for the functions
         called by function we inlined (since number of it inlinable callers
         might change).  */
      update_caller_keys (heap, where, updated_nodes);
      bitmap_clear (updated_nodes);

      if (dump_file)
        {
          fprintf (dump_file, 
                   " Inlined into %s which now has %i insns,"
                   "net change of %+i insns.\n",
                   cgraph_node_name (edge->caller),
                   edge->caller->global.insns,
                   overall_insns - old_insns);
        }
      if (min_insns > overall_insns)
        {
          min_insns = overall_insns;
          max_insns = compute_max_insns (min_insns);

          if (dump_file)
            fprintf (dump_file, "New minimal insns reached: %i\n", min_insns);
        }
    }
  while ((edge = (struct cgraph_edge *) fibheap_extract_min (heap)) != NULL)
    {
      gcc_assert (edge->aux);
      edge->aux = NULL;
      if (!edge->callee->local.disregard_inline_limits && edge->inline_failed
          && !cgraph_recursive_inlining_p (edge->caller, edge->callee,
                                           &edge->inline_failed))
        edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT;
    }

  if (new_indirect_edges)
    VEC_free (cgraph_edge_p, heap, new_indirect_edges);
  fibheap_delete (heap);
  BITMAP_FREE (updated_nodes);
}

/* Decide on the inlining.  We do so in the topological order to avoid
   expenses on updating data structures.  */

static unsigned int
cgraph_decide_inlining (void)
{
  struct cgraph_node *node;
  int nnodes;
  struct cgraph_node **order =
    XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
  int old_insns = 0;
  int i;
  int initial_insns = 0;
  bool redo_always_inline = true;

  cgraph_remove_function_insertion_hook (function_insertion_hook_holder);

  max_count = 0;
  for (node = cgraph_nodes; node; node = node->next)
    if (node->analyzed && (node->needed || node->reachable))
      {
        struct cgraph_edge *e;

        initial_insns += inline_summary (node)->self_insns;
        gcc_assert (inline_summary (node)->self_insns == node->global.insns);
        for (e = node->callees; e; e = e->next_callee)
          if (max_count < e->count)
            max_count = e->count;
      }
  overall_insns = initial_insns;
  gcc_assert (!max_count || (profile_info && flag_branch_probabilities));

  nnodes = cgraph_postorder (order);

  if (dump_file)
    fprintf (dump_file,
             "\nDeciding on inlining.  Starting with %i insns.\n",
             initial_insns);

  for (node = cgraph_nodes; node; node = node->next)
    node->aux = 0;

  if (dump_file)
    fprintf (dump_file, "\nInlining always_inline functions:\n");

  /* In the first pass mark all always_inline edges.  Do this with a priority
     so none of our later choices will make this impossible.  */
  while (redo_always_inline)
    {
      redo_always_inline = false;
      for (i = nnodes - 1; i >= 0; i--)
        {
          struct cgraph_edge *e, *next;

          node = order[i];

          /* Handle nodes to be flattened, but don't update overall unit
             size.  */
          if (lookup_attribute ("flatten",
                                DECL_ATTRIBUTES (node->decl)) != NULL)
            {
              if (dump_file)
                fprintf (dump_file,
                         "Flattening %s\n", cgraph_node_name (node));
              cgraph_decide_inlining_incrementally (node, INLINE_ALL, 0);
            }

          if (!node->local.disregard_inline_limits)
            continue;
          if (dump_file)
            fprintf (dump_file,
                     "\nConsidering %s %i insns (always inline)\n",
                     cgraph_node_name (node), node->global.insns);
          old_insns = overall_insns;
          for (e = node->callers; e; e = next)
            {
              next = e->next_caller;
              if (!e->inline_failed
                  || gimple_call_cannot_inline_p (e->call_stmt))
                continue;
              if (cgraph_recursive_inlining_p (e->caller, e->callee,
                                               &e->inline_failed))
                continue;
              if (!tree_can_inline_p (e->caller->decl, e->callee->decl))
                {
                  gimple_call_set_cannot_inline (e->call_stmt, true);
                  continue;
                }
              if (cgraph_mark_inline_edge (e, true, NULL))
                redo_always_inline = true;
              if (dump_file)
                fprintf (dump_file,
                         " Inlined into %s which now has %i insns.\n",
                         cgraph_node_name (e->caller),
                         e->caller->global.insns);
            }
          /* Inlining self recursive function might introduce new calls to
             themselves we didn't see in the loop above.  Fill in the proper
             reason why inline failed.  */
          for (e = node->callers; e; e = e->next_caller)
            if (e->inline_failed)
              e->inline_failed = CIF_RECURSIVE_INLINING;
          if (dump_file)
            fprintf (dump_file, 
                     " Inlined for a net change of %+i insns.\n",
                     overall_insns - old_insns);
        }
    }

  cgraph_decide_inlining_of_small_functions ();

  if (flag_inline_functions_called_once)
    {
      if (dump_file)
        fprintf (dump_file, "\nDeciding on functions called once:\n");

      /* And finally decide what functions are called once.  */
      for (i = nnodes - 1; i >= 0; i--)
        {
          node = order[i];

          if (node->callers
              && !node->callers->next_caller
              && !node->needed
              && node->local.inlinable
              && node->callers->inline_failed
              && !gimple_call_cannot_inline_p (node->callers->call_stmt)
              && !DECL_EXTERNAL (node->decl)
              && !DECL_COMDAT (node->decl))
            {
              if (dump_file)
                {
                  fprintf (dump_file,
                           "\nConsidering %s %i insns.\n",
                           cgraph_node_name (node), node->global.insns);
                  fprintf (dump_file,
                           " Called once from %s %i insns.\n",
                           cgraph_node_name (node->callers->caller),
                           node->callers->caller->global.insns);
                }

              old_insns = overall_insns;

              if (cgraph_check_inline_limits (node->callers->caller, node,
                                              NULL, false))
                {
                  cgraph_mark_inline (node->callers);
                  if (dump_file)
                    fprintf (dump_file,
                             " Inlined into %s which now has %i insns"
                             " for a net change of %+i insns.\n",
                             cgraph_node_name (node->callers->caller),
                             node->callers->caller->global.insns,
                             overall_insns - old_insns);
                }
              else
                {
                  if (dump_file)
                    fprintf (dump_file,
                             " Inline limit reached, not inlined.\n");
                }
            }
        }
    }

  /* Free ipa-prop structures if they are no longer needed.  */
  if (flag_indirect_inlining)
    free_all_ipa_structures_after_iinln ();

  if (dump_file)
    fprintf (dump_file,
             "\nInlined %i calls, eliminated %i functions, "
             "%i insns turned to %i insns.\n\n",
             ncalls_inlined, nfunctions_inlined, initial_insns,
             overall_insns);
  free (order);
  return 0;
}

/* Try to inline edge E from incremental inliner.  MODE specifies mode
   of inliner.

   We are detecting cycles by storing mode of inliner into cgraph_node last
   time we visited it in the recursion.  In general when mode is set, we have
   recursive inlining, but as an special case, we want to try harder inline
   ALWAYS_INLINE functions: consider callgraph a->b->c->b, with a being
   flatten, b being always inline.  Flattening 'a' will collapse
   a->b->c before hitting cycle.  To accommodate always inline, we however
   need to inline a->b->c->b.

   So after hitting cycle first time, we switch into ALWAYS_INLINE mode and
   stop inlining only after hitting ALWAYS_INLINE in ALWAY_INLINE mode.  */
static bool
try_inline (struct cgraph_edge *e, enum inlining_mode mode, int depth)
{
  struct cgraph_node *callee = e->callee;
  enum inlining_mode callee_mode = (enum inlining_mode) (size_t) callee->aux;
  bool always_inline = e->callee->local.disregard_inline_limits;
  bool inlined = false;

  /* We've hit cycle?  */
  if (callee_mode)
    {
      /* It is first time we see it and we are not in ALWAY_INLINE only
         mode yet.  and the function in question is always_inline.  */
      if (always_inline && mode != INLINE_ALWAYS_INLINE)
        {
          if (dump_file)
            {
              indent_to (dump_file, depth);
              fprintf (dump_file,
                       "Hit cycle in %s, switching to always inline only.\n",
                       cgraph_node_name (callee));
            }
          mode = INLINE_ALWAYS_INLINE;
        }
      /* Otherwise it is time to give up.  */
      else
        {
          if (dump_file)
            {
              indent_to (dump_file, depth);
              fprintf (dump_file,
                       "Not inlining %s into %s to avoid cycle.\n",
                       cgraph_node_name (callee),
                       cgraph_node_name (e->caller));
            }
          e->inline_failed = (e->callee->local.disregard_inline_limits
                              ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED);
          return false;
        }
    }
      
  callee->aux = (void *)(size_t) mode;
  if (dump_file)
    {
      indent_to (dump_file, depth);
      fprintf (dump_file, " Inlining %s into %s.\n",
               cgraph_node_name (e->callee),
               cgraph_node_name (e->caller));
    }
  if (e->inline_failed)
    {
      cgraph_mark_inline (e);

      /* In order to fully inline always_inline functions, we need to
         recurse here, since the inlined functions might not be processed by
         incremental inlining at all yet.  

         Also flattening needs to be done recursively.  */

      if (mode == INLINE_ALL || always_inline)
        cgraph_decide_inlining_incrementally (e->callee, mode, depth + 1);
      inlined = true;
    }
  callee->aux = (void *)(size_t) callee_mode;
  return inlined;
}

/* Decide on the inlining.  We do so in the topological order to avoid
   expenses on updating data structures.  
   DEPTH is depth of recursion, used only for debug output.  */

static bool
cgraph_decide_inlining_incrementally (struct cgraph_node *node,
                                      enum inlining_mode mode,
                                      int depth)
{
  struct cgraph_edge *e;
  bool inlined = false;
  cgraph_inline_failed_t failed_reason;
  enum inlining_mode old_mode;

#ifdef ENABLE_CHECKING
  verify_cgraph_node (node);
#endif

  old_mode = (enum inlining_mode) (size_t)node->aux;

  if (mode != INLINE_ALWAYS_INLINE && mode != INLINE_SIZE_NORECURSIVE
      && lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) != NULL)
    {
      if (dump_file)
        {
          indent_to (dump_file, depth);
          fprintf (dump_file, "Flattening %s\n", cgraph_node_name (node));
        }
      mode = INLINE_ALL;
    }

  node->aux = (void *)(size_t) mode;

  /* First of all look for always inline functions.  */
  if (mode != INLINE_SIZE_NORECURSIVE)
    for (e = node->callees; e; e = e->next_callee)
      {
        if (!e->callee->local.disregard_inline_limits
            && (mode != INLINE_ALL || !e->callee->local.inlinable))
          continue;
        if (gimple_call_cannot_inline_p (e->call_stmt))
          continue;
        /* When the edge is already inlined, we just need to recurse into
           it in order to fully flatten the leaves.  */
        if (!e->inline_failed && mode == INLINE_ALL)
          {
            inlined |= try_inline (e, mode, depth);
            continue;
          }
        if (dump_file)
          {
            indent_to (dump_file, depth);
            fprintf (dump_file,
                     "Considering to always inline inline candidate %s.\n",
                     cgraph_node_name (e->callee));
          }
        if (cgraph_recursive_inlining_p (node, e->callee, &e->inline_failed))
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file, "Not inlining: recursive call.\n");
              }
            continue;
          }
        if (!tree_can_inline_p (node->decl, e->callee->decl))
          {
            gimple_call_set_cannot_inline (e->call_stmt, true);
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file,
                         "Not inlining: Target specific option mismatch.\n");
              }
            continue;
          }
        if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
            != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->callee->decl)))
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file, "Not inlining: SSA form does not match.\n");
              }
            continue;
          }
        if (!e->callee->analyzed)
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file,
                         "Not inlining: Function body no longer available.\n");
              }
            continue;
          }
        inlined |= try_inline (e, mode, depth);
      }

  /* Now do the automatic inlining.  */
  if (mode != INLINE_ALL && mode != INLINE_ALWAYS_INLINE)
    for (e = node->callees; e; e = e->next_callee)
      {
        if (!e->callee->local.inlinable
            || !e->inline_failed
            || e->callee->local.disregard_inline_limits)
          continue;
        if (dump_file)
          fprintf (dump_file, "Considering inline candidate %s.\n",
                   cgraph_node_name (e->callee));
        if (cgraph_recursive_inlining_p (node, e->callee, &e->inline_failed))
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file, "Not inlining: recursive call.\n");
              }
            continue;
          }
        if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl))
            != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->callee->decl)))
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file, "Not inlining: SSA form does not match.\n");
              }
            continue;
          }
        /* When the function body would grow and inlining the function won't
           eliminate the need for offline copy of the function, don't inline.
         */
        if (((mode == INLINE_SIZE || mode == INLINE_SIZE_NORECURSIVE)
             || (!flag_inline_functions
                 && !DECL_DECLARED_INLINE_P (e->callee->decl)))
            && (cgraph_estimate_size_after_inlining (1, e->caller, e->callee)
                > e->caller->global.insns)
            && cgraph_estimate_growth (e->callee) > 0)
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file,
                         "Not inlining: code size would grow by %i insns.\n",
                         cgraph_estimate_size_after_inlining (1, e->caller,
                                                              e->callee)
                         - e->caller->global.insns);
              }
            continue;
          }
        if (!cgraph_check_inline_limits (node, e->callee, &e->inline_failed,
                                        false)
            || gimple_call_cannot_inline_p (e->call_stmt))
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file, "Not inlining: %s.\n",
                         cgraph_inline_failed_string (e->inline_failed));
              }
            continue;
          }
        if (!e->callee->analyzed)
          {
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file,
                         "Not inlining: Function body no longer available.\n");
              }
            continue;
          }
        if (!tree_can_inline_p (node->decl, e->callee->decl))
          {
            gimple_call_set_cannot_inline (e->call_stmt, true);
            if (dump_file)
              {
                indent_to (dump_file, depth);
                fprintf (dump_file,
                         "Not inlining: Target specific option mismatch.\n");
              }
            continue;
          }
        if (cgraph_default_inline_p (e->callee, &failed_reason))
          inlined |= try_inline (e, mode, depth);
      }
  node->aux = (void *)(size_t) old_mode;
  return inlined;
}

/* Because inlining might remove no-longer reachable nodes, we need to
   keep the array visible to garbage collector to avoid reading collected
   out nodes.  */
static int nnodes;
static GTY ((length ("nnodes"))) struct cgraph_node **order;

/* Do inlining of small functions.  Doing so early helps profiling and other
   passes to be somewhat more effective and avoids some code duplication in
   later real inlining pass for testcases with very many function calls.  */
static unsigned int
cgraph_early_inlining (void)
{
  struct cgraph_node *node = cgraph_node (current_function_decl);
  unsigned int todo = 0;
  int iterations = 0;

  if (sorrycount || errorcount)
    return 0;
  while (cgraph_decide_inlining_incrementally (node,
                                               iterations
                                               ? INLINE_SIZE_NORECURSIVE : INLINE_SIZE, 0)
         && iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS))
    {
      timevar_push (TV_INTEGRATION);
      todo |= optimize_inline_calls (current_function_decl);
      iterations++;
      timevar_pop (TV_INTEGRATION);
    }
  if (dump_file)
    fprintf (dump_file, "Iterations: %i\n", iterations);
  cfun->always_inline_functions_inlined = true;
  return todo;
}

/* When inlining shall be performed.  */
static bool
cgraph_gate_early_inlining (void)
{
  return flag_early_inlining;
}

struct gimple_opt_pass pass_early_inline = 
{
 {
  GIMPLE_PASS,
  "einline",                            /* name */
  cgraph_gate_early_inlining,           /* gate */
  cgraph_early_inlining,                /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_INLINE_HEURISTICS,                 /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  TODO_dump_func                        /* todo_flags_finish */
 }
};

/* When inlining shall be performed.  */
static bool
cgraph_gate_ipa_early_inlining (void)
{
  return (flag_early_inlining
          && (flag_branch_probabilities || flag_test_coverage
              || profile_arc_flag));
}

/* IPA pass wrapper for early inlining pass.  We need to run early inlining
   before tree profiling so we have stand alone IPA pass for doing so.  */
struct simple_ipa_opt_pass pass_ipa_early_inline = 
{
 {
  SIMPLE_IPA_PASS,
  "einline_ipa",                        /* name */
  cgraph_gate_ipa_early_inlining,       /* gate */
  NULL,                                 /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_INLINE_HEURISTICS,                 /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  TODO_dump_cgraph                      /* todo_flags_finish */
 }
};

/* Compute parameters of functions used by inliner.  */
unsigned int
compute_inline_parameters (struct cgraph_node *node)
{
  HOST_WIDE_INT self_stack_size;

  gcc_assert (!node->global.inlined_to);

  /* Estimate the stack size for the function.  But not at -O0
     because estimated_stack_frame_size is a quadratic problem.  */
  self_stack_size = optimize ? estimated_stack_frame_size () : 0;
  inline_summary (node)->estimated_self_stack_size = self_stack_size;
  node->global.estimated_stack_size = self_stack_size;
  node->global.stack_frame_offset = 0;

  /* Can this function be inlined at all?  */
  node->local.inlinable = tree_inlinable_function_p (current_function_decl);

  /* Estimate the number of instructions for this function.
     ??? At -O0 we don't use this information except for the dumps, and
         even then only for always_inline functions.  But disabling this
         causes ICEs in the inline heuristics...  */
  inline_summary (node)->self_insns
      = estimate_num_insns_fn (current_function_decl, &eni_inlining_weights);
  if (node->local.inlinable && !node->local.disregard_inline_limits)
    node->local.disregard_inline_limits
      = DECL_DISREGARD_INLINE_LIMITS (current_function_decl);

  /* Inlining characteristics are maintained by the cgraph_mark_inline.  */
  node->global.insns = inline_summary (node)->self_insns;
  return 0;
}


/* Compute parameters of functions used by inliner using
   current_function_decl.  */
static unsigned int
compute_inline_parameters_for_current (void)
{
  compute_inline_parameters (cgraph_node (current_function_decl));
  return 0;
}

struct gimple_opt_pass pass_inline_parameters = 
{
 {
  GIMPLE_PASS,
  NULL,                                 /* name */
  NULL,                                 /* gate */
  compute_inline_parameters_for_current,/* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_INLINE_HEURISTICS,                 /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0                                     /* todo_flags_finish */
 }
};

/* This function performs intraprocedural analyzis in NODE that is required to
   inline indirect calls.  */
static void
inline_indirect_intraprocedural_analysis (struct cgraph_node *node)
{
  struct cgraph_edge *cs;

  if (!flag_ipa_cp)
    {
      ipa_initialize_node_params (node);
      ipa_detect_param_modifications (node);
    }
  ipa_analyze_params_uses (node);

  if (!flag_ipa_cp)
    for (cs = node->callees; cs; cs = cs->next_callee)
      {
        ipa_count_arguments (cs);
        ipa_compute_jump_functions (cs);
      }

  if (dump_file)
    {
      ipa_print_node_params (dump_file, node);
      ipa_print_node_jump_functions (dump_file, node);
    }
}

/* Note function body size.  */
static void
analyze_function (struct cgraph_node *node)
{
  push_cfun (DECL_STRUCT_FUNCTION (node->decl));
  current_function_decl = node->decl;

  compute_inline_parameters (node);
  if (flag_indirect_inlining)
    inline_indirect_intraprocedural_analysis (node);

  current_function_decl = NULL;
  pop_cfun ();
}

/* Called when new function is inserted to callgraph late.  */
static void
add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
{
  analyze_function (node);
}

/* Note function body size.  */
static void
inline_generate_summary (void)
{
  struct cgraph_node *node;

  function_insertion_hook_holder =
      cgraph_add_function_insertion_hook (&add_new_function, NULL);

  if (flag_indirect_inlining)
    {
      ipa_register_cgraph_hooks ();
      ipa_check_create_node_params ();
      ipa_check_create_edge_args ();
    }

  for (node = cgraph_nodes; node; node = node->next)
    if (node->analyzed)
      analyze_function (node);
  
  return;
}

/* Apply inline plan to function.  */
static unsigned int
inline_transform (struct cgraph_node *node)
{
  unsigned int todo = 0;
  struct cgraph_edge *e;

  /* We might need the body of this function so that we can expand
     it inline somewhere else.  */
  if (cgraph_preserve_function_body_p (node->decl))
    save_inline_function_body (node);

  for (e = node->callees; e; e = e->next_callee)
    if (!e->inline_failed || warn_inline)
      break;

  if (e)
    {
      timevar_push (TV_INTEGRATION);
      todo = optimize_inline_calls (current_function_decl);
      timevar_pop (TV_INTEGRATION);
    }
  cfun->always_inline_functions_inlined = true;
  cfun->after_inlining = true;
  return todo | execute_fixup_cfg ();
}

struct ipa_opt_pass_d pass_ipa_inline =
{
 {
  IPA_PASS,
  "inline",                             /* name */
  NULL,                                 /* gate */
  cgraph_decide_inlining,               /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_INLINE_HEURISTICS,                 /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  TODO_remove_functions,                /* todo_flags_finish */
  TODO_dump_cgraph | TODO_dump_func
  | TODO_remove_functions               /* todo_flags_finish */
 },
 inline_generate_summary,               /* generate_summary */
 NULL,                                  /* write_summary */
 NULL,                                  /* read_summary */
 NULL,                                  /* function_read_summary */
 0,                                     /* TODOs */
 inline_transform,                      /* function_transform */
 NULL,                                  /* variable_transform */
};


#include "gt-ipa-inline.h"