gcc/ipa-cp.c

/* Interprocedural constant propagation
   Copyright (C) 2005-2015 Free Software Foundation, Inc.

   Contributed by Razya Ladelsky <RAZYA@il.ibm.com> and Martin Jambor
   <mjambor@suse.cz>

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/>.  */

/* Interprocedural constant propagation (IPA-CP).

   The goal of this transformation is to

   1) discover functions which are always invoked with some arguments with the
      same known constant values and modify the functions so that the
      subsequent optimizations can take advantage of the knowledge, and

   2) partial specialization - create specialized versions of functions
      transformed in this way if some parameters are known constants only in
      certain contexts but the estimated tradeoff between speedup and cost size
      is deemed good.

   The algorithm also propagates types and attempts to perform type based
   devirtualization.  Types are propagated much like constants.

   The algorithm basically consists of three stages.  In the first, functions
   are analyzed one at a time and jump functions are constructed for all known
   call-sites.  In the second phase, the pass propagates information from the
   jump functions across the call to reveal what values are available at what
   call sites, performs estimations of effects of known values on functions and
   their callees, and finally decides what specialized extra versions should be
   created.  In the third, the special versions materialize and appropriate
   calls are redirected.

   The algorithm used is to a certain extent based on "Interprocedural Constant
   Propagation", by David Callahan, Keith D Cooper, Ken Kennedy, Linda Torczon,
   Comp86, pg 152-161 and "A Methodology for Procedure Cloning" by Keith D
   Cooper, Mary W. Hall, and Ken Kennedy.


   First stage - intraprocedural analysis
   =======================================

   This phase computes jump_function and modification flags.

   A jump function for a call-site represents the values passed as an actual
   arguments of a given call-site. In principle, there are three types of
   values:

   Pass through - the caller's formal parameter is passed as an actual
                  argument, plus an operation on it can be performed.
   Constant - a constant is passed as an actual argument.
   Unknown - neither of the above.

   All jump function types are described in detail in ipa-prop.h, together with
   the data structures that represent them and methods of accessing them.

   ipcp_generate_summary() is the main function of the first stage.

   Second stage - interprocedural analysis
   ========================================

   This stage is itself divided into two phases.  In the first, we propagate
   known values over the call graph, in the second, we make cloning decisions.
   It uses a different algorithm than the original Callahan's paper.

   First, we traverse the functions topologically from callers to callees and,
   for each strongly connected component (SCC), we propagate constants
   according to previously computed jump functions.  We also record what known
   values depend on other known values and estimate local effects.  Finally, we
   propagate cumulative information about these effects from dependent values
   to those on which they depend.

   Second, we again traverse the call graph in the same topological order and
   make clones for functions which we know are called with the same values in
   all contexts and decide about extra specialized clones of functions just for
   some contexts - these decisions are based on both local estimates and
   cumulative estimates propagated from callees.

   ipcp_propagate_stage() and ipcp_decision_stage() together constitute the
   third stage.

   Third phase - materialization of clones, call statement updates.
   ============================================

   This stage is currently performed by call graph code (mainly in cgraphunit.c
   and tree-inline.c) according to instructions inserted to the call graph by
   the second stage.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "hash-set.h"
#include "machmode.h"
#include "vec.h"
#include "hash-map.h"
#include "double-int.h"
#include "input.h"
#include "alias.h"
#include "symtab.h"
#include "options.h"
#include "wide-int.h"
#include "inchash.h"
#include "tree.h"
#include "fold-const.h"
#include "gimple-fold.h"
#include "gimple-expr.h"
#include "target.h"
#include "predict.h"
#include "basic-block.h"
#include "is-a.h"
#include "plugin-api.h"
#include "tm.h"
#include "hard-reg-set.h"
#include "input.h"
#include "function.h"
#include "ipa-ref.h"
#include "cgraph.h"
#include "alloc-pool.h"
#include "symbol-summary.h"
#include "ipa-prop.h"
#include "bitmap.h"
#include "tree-pass.h"
#include "flags.h"
#include "diagnostic.h"
#include "tree-pretty-print.h"
#include "tree-inline.h"
#include "params.h"
#include "ipa-inline.h"
#include "ipa-utils.h"

template <typename valtype> class ipcp_value;

/* Describes a particular source for an IPA-CP value.  */

template <typename valtype>
class ipcp_value_source
{
public:
  /* Aggregate offset of the source, negative if the source is scalar value of
     the argument itself.  */
  HOST_WIDE_INT offset;
  /* The incoming edge that brought the value.  */
  cgraph_edge *cs;
  /* If the jump function that resulted into his value was a pass-through or an
     ancestor, this is the ipcp_value of the caller from which the described
     value has been derived.  Otherwise it is NULL.  */
  ipcp_value<valtype> *val;
  /* Next pointer in a linked list of sources of a value.  */
  ipcp_value_source *next;
  /* If the jump function that resulted into his value was a pass-through or an
     ancestor, this is the index of the parameter of the caller the jump
     function references.  */
  int index;
};

/* Common ancestor for all ipcp_value instantiations.  */

class ipcp_value_base
{
public:
  /* Time benefit and size cost that specializing the function for this value
     would bring about in this function alone.  */
  int local_time_benefit, local_size_cost;
  /* Time benefit and size cost that specializing the function for this value
     can bring about in it's callees (transitively).  */
  int prop_time_benefit, prop_size_cost;
};

/* Describes one particular value stored in struct ipcp_lattice.  */

template <typename valtype>
class ipcp_value : public ipcp_value_base
{
public:
  /* The actual value for the given parameter.  */
  valtype value;
  /* The list of sources from which this value originates.  */
  ipcp_value_source <valtype> *sources;
  /* Next pointers in a linked list of all values in a lattice.  */
  ipcp_value *next;
  /* Next pointers in a linked list of values in a strongly connected component
     of values. */
  ipcp_value *scc_next;
  /* Next pointers in a linked list of SCCs of values sorted topologically
     according their sources.  */
  ipcp_value  *topo_next;
  /* A specialized node created for this value, NULL if none has been (so far)
     created.  */
  cgraph_node *spec_node;
  /* Depth first search number and low link for topological sorting of
     values.  */
  int dfs, low_link;
  /* True if this valye is currently on the topo-sort stack.  */
  bool on_stack;

  void add_source (cgraph_edge *cs, ipcp_value *src_val, int src_idx,
		   HOST_WIDE_INT offset);
};

/* Lattice describing potential values of a formal parameter of a function, or
   a part of an aggreagate.  TOP is represented by a lattice with zero values
   and with contains_variable and bottom flags cleared.  BOTTOM is represented
   by a lattice with the bottom flag set.  In that case, values and
   contains_variable flag should be disregarded.  */

template <typename valtype>
class ipcp_lattice
{
public:
  /* The list of known values and types in this lattice.  Note that values are
     not deallocated if a lattice is set to bottom because there may be value
     sources referencing them.  */
  ipcp_value<valtype> *values;
  /* Number of known values and types in this lattice.  */
  int values_count;
  /* The lattice contains a variable component (in addition to values).  */
  bool contains_variable;
  /* The value of the lattice is bottom (i.e. variable and unusable for any
     propagation).  */
  bool bottom;

  inline bool is_single_const ();
  inline bool set_to_bottom ();
  inline bool set_contains_variable ();
  bool add_value (valtype newval, cgraph_edge *cs,
		  ipcp_value<valtype> *src_val = NULL,
		  int src_idx = 0, HOST_WIDE_INT offset = -1);
  void print (FILE * f, bool dump_sources, bool dump_benefits);
};

/* Lattice of tree values with an offset to describe a part of an
   aggregate.  */

class ipcp_agg_lattice : public ipcp_lattice<tree>
{
public:
  /* Offset that is being described by this lattice. */
  HOST_WIDE_INT offset;
  /* Size so that we don't have to re-compute it every time we traverse the
     list.  Must correspond to TYPE_SIZE of all lat values.  */
  HOST_WIDE_INT size;
  /* Next element of the linked list.  */
  struct ipcp_agg_lattice *next;
};

/* Structure containing lattices for a parameter itself and for pieces of
   aggregates that are passed in the parameter or by a reference in a parameter
   plus some other useful flags.  */

class ipcp_param_lattices
{
public:
  /* Lattice describing the value of the parameter itself.  */
  ipcp_lattice<tree> itself;
  /* Lattice describing the the polymorphic contexts of a parameter.  */
  ipcp_lattice<ipa_polymorphic_call_context> ctxlat;
  /* Lattices describing aggregate parts.  */
  ipcp_agg_lattice *aggs;
  /* Alignment information.  Very basic one value lattice where !known means
     TOP and zero alignment bottom.  */
  ipa_alignment alignment;
  /* Number of aggregate lattices */
  int aggs_count;
  /* True if aggregate data were passed by reference (as opposed to by
     value).  */
  bool aggs_by_ref;
  /* All aggregate lattices contain a variable component (in addition to
     values).  */
  bool aggs_contain_variable;
  /* The value of all aggregate lattices is bottom (i.e. variable and unusable
     for any propagation).  */
  bool aggs_bottom;

  /* There is a virtual call based on this parameter.  */
  bool virt_call;
};

/* Allocation pools for values and their sources in ipa-cp.  */

alloc_pool ipcp_cst_values_pool;
alloc_pool ipcp_poly_ctx_values_pool;
alloc_pool ipcp_sources_pool;
alloc_pool ipcp_agg_lattice_pool;

/* Maximal count found in program.  */

static gcov_type max_count;

/* Original overall size of the program.  */

static long overall_size, max_new_size;

/* Return the param lattices structure corresponding to the Ith formal
   parameter of the function described by INFO.  */
static inline struct ipcp_param_lattices *
ipa_get_parm_lattices (struct ipa_node_params *info, int i)
{
  gcc_assert (i >= 0 && i < ipa_get_param_count (info));
  gcc_checking_assert (!info->ipcp_orig_node);
  gcc_checking_assert (info->lattices);
  return &(info->lattices[i]);
}

/* Return the lattice corresponding to the scalar value of the Ith formal
   parameter of the function described by INFO.  */
static inline ipcp_lattice<tree> *
ipa_get_scalar_lat (struct ipa_node_params *info, int i)
{
  struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
  return &plats->itself;
}

/* Return the lattice corresponding to the scalar value of the Ith formal
   parameter of the function described by INFO.  */
static inline ipcp_lattice<ipa_polymorphic_call_context> *
ipa_get_poly_ctx_lat (struct ipa_node_params *info, int i)
{
  struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
  return &plats->ctxlat;
}

/* Return whether LAT is a lattice with a single constant and without an
   undefined value.  */

template <typename valtype>
inline bool
ipcp_lattice<valtype>::is_single_const ()
{
  if (bottom || contains_variable || values_count != 1)
    return false;
  else
    return true;
}

/* Print V which is extracted from a value in a lattice to F.  */

static void
print_ipcp_constant_value (FILE * f, tree v)
{
  if (TREE_CODE (v) == ADDR_EXPR
	   && TREE_CODE (TREE_OPERAND (v, 0)) == CONST_DECL)
    {
      fprintf (f, "& ");
      print_generic_expr (f, DECL_INITIAL (TREE_OPERAND (v, 0)), 0);
    }
  else
    print_generic_expr (f, v, 0);
}

/* Print V which is extracted from a value in a lattice to F.  */

static void
print_ipcp_constant_value (FILE * f, ipa_polymorphic_call_context v)
{
  v.dump(f, false);
}

/* Print a lattice LAT to F.  */

template <typename valtype>
void
ipcp_lattice<valtype>::print (FILE * f, bool dump_sources, bool dump_benefits)
{
  ipcp_value<valtype> *val;
  bool prev = false;

  if (bottom)
    {
      fprintf (f, "BOTTOM\n");
      return;
    }

  if (!values_count && !contains_variable)
    {
      fprintf (f, "TOP\n");
      return;
    }

  if (contains_variable)
    {
      fprintf (f, "VARIABLE");
      prev = true;
      if (dump_benefits)
	fprintf (f, "\n");
    }

  for (val = values; val; val = val->next)
    {
      if (dump_benefits && prev)
	fprintf (f, "               ");
      else if (!dump_benefits && prev)
	fprintf (f, ", ");
      else
	prev = true;

      print_ipcp_constant_value (f, val->value);

      if (dump_sources)
	{
	  ipcp_value_source<valtype> *s;

	  fprintf (f, " [from:");
	  for (s = val->sources; s; s = s->next)
	    fprintf (f, " %i(%i)", s->cs->caller->order,
		     s->cs->frequency);
	  fprintf (f, "]");
	}

      if (dump_benefits)
	fprintf (f, " [loc_time: %i, loc_size: %i, "
		 "prop_time: %i, prop_size: %i]\n",
		 val->local_time_benefit, val->local_size_cost,
		 val->prop_time_benefit, val->prop_size_cost);
    }
  if (!dump_benefits)
    fprintf (f, "\n");
}

/* Print all ipcp_lattices of all functions to F.  */

static void
print_all_lattices (FILE * f, bool dump_sources, bool dump_benefits)
{
  struct cgraph_node *node;
  int i, count;

  fprintf (f, "\nLattices:\n");
  FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (node)
    {
      struct ipa_node_params *info;

      info = IPA_NODE_REF (node);
      fprintf (f, "  Node: %s/%i:\n", node->name (),
	       node->order);
      count = ipa_get_param_count (info);
      for (i = 0; i < count; i++)
	{
	  struct ipcp_agg_lattice *aglat;
	  struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
	  fprintf (f, "    param [%d]: ", i);
	  plats->itself.print (f, dump_sources, dump_benefits);
	  fprintf (f, "         ctxs: ");
	  plats->ctxlat.print (f, dump_sources, dump_benefits);
	  if (plats->alignment.known && plats->alignment.align > 0)
	    fprintf (f, "         Alignment %u, misalignment %u\n",
		     plats->alignment.align, plats->alignment.misalign);
	  else if (plats->alignment.known)
	    fprintf (f, "         Alignment unusable\n");
	  else
	    fprintf (f, "         Alignment unknown\n");
	  if (plats->virt_call)
	    fprintf (f, "        virt_call flag set\n");

	  if (plats->aggs_bottom)
	    {
	      fprintf (f, "        AGGS BOTTOM\n");
	      continue;
	    }
	  if (plats->aggs_contain_variable)
	    fprintf (f, "        AGGS VARIABLE\n");
	  for (aglat = plats->aggs; aglat; aglat = aglat->next)
	    {
	      fprintf (f, "        %soffset " HOST_WIDE_INT_PRINT_DEC ": ",
		       plats->aggs_by_ref ? "ref " : "", aglat->offset);
	      aglat->print (f, dump_sources, dump_benefits);
	    }
	}
    }
}

/* Determine whether it is at all technically possible to create clones of NODE
   and store this information in the ipa_node_params structure associated
   with NODE.  */

static void
determine_versionability (struct cgraph_node *node)
{
  const char *reason = NULL;

  /* There are a number of generic reasons functions cannot be versioned.  We
     also cannot remove parameters if there are type attributes such as fnspec
     present.  */
  if (node->alias || node->thunk.thunk_p)
    reason = "alias or thunk";
  else if (!node->local.versionable)
    reason = "not a tree_versionable_function";
  else if (node->get_availability () <= AVAIL_INTERPOSABLE)
    reason = "insufficient body availability";
  else if (!opt_for_fn (node->decl, optimize)
	   || !opt_for_fn (node->decl, flag_ipa_cp))
    reason = "non-optimized function";
  else if (lookup_attribute ("omp declare simd", DECL_ATTRIBUTES (node->decl)))
    {
      /* Ideally we should clone the SIMD clones themselves and create
	 vector copies of them, so IPA-cp and SIMD clones can happily
	 coexist, but that may not be worth the effort.  */
      reason = "function has SIMD clones";
    }
  /* Don't clone decls local to a comdat group; it breaks and for C++
     decloned constructors, inlining is always better anyway.  */
  else if (node->comdat_local_p ())
    reason = "comdat-local function";
  else if (node->calls_comdat_local)
    {
      /* TODO: call is versionable if we make sure that all
	 callers are inside of a comdat group.  */
      reason = "calls comdat-local function";
    }

  if (reason && dump_file && !node->alias && !node->thunk.thunk_p)
    fprintf (dump_file, "Function %s/%i is not versionable, reason: %s.\n",
	     node->name (), node->order, reason);

  node->local.versionable = (reason == NULL);
}

/* Return true if it is at all technically possible to create clones of a
   NODE.  */

static bool
ipcp_versionable_function_p (struct cgraph_node *node)
{
  return node->local.versionable;
}

/* Structure holding accumulated information about callers of a node.  */

struct caller_statistics
{
  gcov_type count_sum;
  int n_calls, n_hot_calls, freq_sum;
};

/* Initialize fields of STAT to zeroes.  */

static inline void
init_caller_stats (struct caller_statistics *stats)
{
  stats->count_sum = 0;
  stats->n_calls = 0;
  stats->n_hot_calls = 0;
  stats->freq_sum = 0;
}

/* Worker callback of cgraph_for_node_and_aliases accumulating statistics of
   non-thunk incoming edges to NODE.  */

static bool
gather_caller_stats (struct cgraph_node *node, void *data)
{
  struct caller_statistics *stats = (struct caller_statistics *) data;
  struct cgraph_edge *cs;

  for (cs = node->callers; cs; cs = cs->next_caller)
    if (!cs->caller->thunk.thunk_p)
      {
	stats->count_sum += cs->count;
	stats->freq_sum += cs->frequency;
	stats->n_calls++;
	if (cs->maybe_hot_p ())
	  stats->n_hot_calls ++;
      }
  return false;

}

/* Return true if this NODE is viable candidate for cloning.  */

static bool
ipcp_cloning_candidate_p (struct cgraph_node *node)
{
  struct caller_statistics stats;

  gcc_checking_assert (node->has_gimple_body_p ());

  if (!opt_for_fn (node->decl, flag_ipa_cp_clone))
    {
      if (dump_file)
        fprintf (dump_file, "Not considering %s for cloning; "
		 "-fipa-cp-clone disabled.\n",
 	         node->name ());
      return false;
    }

  if (!optimize_function_for_speed_p (DECL_STRUCT_FUNCTION (node->decl)))
    {
      if (dump_file)
        fprintf (dump_file, "Not considering %s for cloning; "
		 "optimizing it for size.\n",
 	         node->name ());
      return false;
    }

  init_caller_stats (&stats);
  node->call_for_symbol_thunks_and_aliases (gather_caller_stats, &stats, false);

  if (inline_summaries->get (node)->self_size < stats.n_calls)
    {
      if (dump_file)
        fprintf (dump_file, "Considering %s for cloning; code might shrink.\n",
 	         node->name ());
      return true;
    }

  /* When profile is available and function is hot, propagate into it even if
     calls seems cold; constant propagation can improve function's speed
     significantly.  */
  if (max_count)
    {
      if (stats.count_sum > node->count * 90 / 100)
	{
	  if (dump_file)
	    fprintf (dump_file, "Considering %s for cloning; "
		     "usually called directly.\n",
		     node->name ());
	  return true;
        }
    }
  if (!stats.n_hot_calls)
    {
      if (dump_file)
	fprintf (dump_file, "Not considering %s for cloning; no hot calls.\n",
		 node->name ());
      return false;
    }
  if (dump_file)
    fprintf (dump_file, "Considering %s for cloning.\n",
	     node->name ());
  return true;
}

template <typename valtype>
class value_topo_info
{
public:
  /* Head of the linked list of topologically sorted values. */
  ipcp_value<valtype> *values_topo;
  /* Stack for creating SCCs, represented by a linked list too.  */
  ipcp_value<valtype> *stack;
  /* Counter driving the algorithm in add_val_to_toposort.  */
  int dfs_counter;

  value_topo_info () : values_topo (NULL), stack (NULL), dfs_counter (0)
  {}
  void add_val (ipcp_value<valtype> *cur_val);
  void propagate_effects ();
};

/* Arrays representing a topological ordering of call graph nodes and a stack
   of nodes used during constant propagation and also data required to perform
   topological sort of values and propagation of benefits in the determined
   order.  */

class ipa_topo_info
{
public:
  /* Array with obtained topological order of cgraph nodes.  */
  struct cgraph_node **order;
  /* Stack of cgraph nodes used during propagation within SCC until all values
     in the SCC stabilize.  */
  struct cgraph_node **stack;
  int nnodes, stack_top;

  value_topo_info<tree> constants;
  value_topo_info<ipa_polymorphic_call_context> contexts;

  ipa_topo_info () : order(NULL), stack(NULL), nnodes(0), stack_top(0),
    constants ()
  {}
};

/* Allocate the arrays in TOPO and topologically sort the nodes into order.  */

static void
build_toporder_info (struct ipa_topo_info *topo)
{
  topo->order = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
  topo->stack = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);

  gcc_checking_assert (topo->stack_top == 0);
  topo->nnodes = ipa_reduced_postorder (topo->order, true, true, NULL);
}

/* Free information about strongly connected components and the arrays in
   TOPO.  */

static void
free_toporder_info (struct ipa_topo_info *topo)
{
  ipa_free_postorder_info ();
  free (topo->order);
  free (topo->stack);
}

/* Add NODE to the stack in TOPO, unless it is already there.  */

static inline void
push_node_to_stack (struct ipa_topo_info *topo, struct cgraph_node *node)
{
  struct ipa_node_params *info = IPA_NODE_REF (node);
  if (info->node_enqueued)
    return;
  info->node_enqueued = 1;
  topo->stack[topo->stack_top++] = node;
}

/* Pop a node from the stack in TOPO and return it or return NULL if the stack
   is empty.  */

static struct cgraph_node *
pop_node_from_stack (struct ipa_topo_info *topo)
{
  if (topo->stack_top)
    {
      struct cgraph_node *node;
      topo->stack_top--;
      node = topo->stack[topo->stack_top];
      IPA_NODE_REF (node)->node_enqueued = 0;
      return node;
    }
  else
    return NULL;
}

/* Set lattice LAT to bottom and return true if it previously was not set as
   such.  */

template <typename valtype>
inline bool
ipcp_lattice<valtype>::set_to_bottom ()
{
  bool ret = !bottom;
  bottom = true;
  return ret;
}

/* Mark lattice as containing an unknown value and return true if it previously
   was not marked as such.  */

template <typename valtype>
inline bool
ipcp_lattice<valtype>::set_contains_variable ()
{
  bool ret = !contains_variable;
  contains_variable = true;
  return ret;
}

/* Set all aggegate lattices in PLATS to bottom and return true if they were
   not previously set as such.  */

static inline bool
set_agg_lats_to_bottom (struct ipcp_param_lattices *plats)
{
  bool ret = !plats->aggs_bottom;
  plats->aggs_bottom = true;
  return ret;
}

/* Mark all aggegate lattices in PLATS as containing an unknown value and
   return true if they were not previously marked as such.  */

static inline bool
set_agg_lats_contain_variable (struct ipcp_param_lattices *plats)
{
  bool ret = !plats->aggs_contain_variable;
  plats->aggs_contain_variable = true;
  return ret;
}

/* Return true if alignment information in PLATS is known to be unusable.  */

static inline bool
alignment_bottom_p (ipcp_param_lattices *plats)
{
  return plats->alignment.known && (plats->alignment.align == 0);
}

/* Set alignment information in PLATS to unusable.  Return true if it
   previously was usable or unknown.  */

static inline bool
set_alignment_to_bottom (ipcp_param_lattices *plats)
{
  if (alignment_bottom_p (plats))
    return false;
  plats->alignment.known = true;
  plats->alignment.align = 0;
  return true;
}

/* Mark bot aggregate and scalar lattices as containing an unknown variable,
   return true is any of them has not been marked as such so far.  */

static inline bool
set_all_contains_variable (struct ipcp_param_lattices *plats)
{
  bool ret;
  ret = plats->itself.set_contains_variable ();
  ret |= plats->ctxlat.set_contains_variable ();
  ret |= set_agg_lats_contain_variable (plats);
  ret |= set_alignment_to_bottom (plats);
  return ret;
}

/* Worker of call_for_symbol_thunks_and_aliases, increment the integer DATA
   points to by the number of callers to NODE.  */

static bool
count_callers (cgraph_node *node, void *data)
{
  int *caller_count = (int *) data;

  for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
    /* Local thunks can be handled transparently, but if the thunk can not
       be optimized out, count it as a real use.  */
    if (!cs->caller->thunk.thunk_p || !cs->caller->local.local)
      ++*caller_count;
  return false;
}

/* Worker of call_for_symbol_thunks_and_aliases, it is supposed to be called on
   the one caller of some other node.  Set the caller's corresponding flag.  */

static bool
set_single_call_flag (cgraph_node *node, void *)
{
  cgraph_edge *cs = node->callers;
  /* Local thunks can be handled transparently, skip them.  */
  while (cs && cs->caller->thunk.thunk_p && cs->caller->local.local)
    cs = cs->next_caller;
  if (cs)
    {
      IPA_NODE_REF (cs->caller)->node_calling_single_call = true;
      return true;
    }
  return false;
}

/* Initialize ipcp_lattices.  */

static void
initialize_node_lattices (struct cgraph_node *node)
{
  struct ipa_node_params *info = IPA_NODE_REF (node);
  struct cgraph_edge *ie;
  bool disable = false, variable = false;
  int i;

  gcc_checking_assert (node->has_gimple_body_p ());
  if (cgraph_local_p (node))
    {
      int caller_count = 0;
      node->call_for_symbol_thunks_and_aliases (count_callers, &caller_count,
						true);
      gcc_checking_assert (caller_count > 0);
      if (caller_count == 1)
	node->call_for_symbol_thunks_and_aliases (set_single_call_flag,
						  NULL, true);
    }
  else
    {
      /* When cloning is allowed, we can assume that externally visible
	 functions are not called.  We will compensate this by cloning
	 later.  */
      if (ipcp_versionable_function_p (node)
	  && ipcp_cloning_candidate_p (node))
	variable = true;
      else
	disable = true;
    }

  if (disable || variable)
    {
      for (i = 0; i < ipa_get_param_count (info) ; i++)
	{
	  struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
	  if (disable)
	    {
	      plats->itself.set_to_bottom ();
	      plats->ctxlat.set_to_bottom ();
	      set_agg_lats_to_bottom (plats);
	      set_alignment_to_bottom (plats);
	    }
	  else
	    set_all_contains_variable (plats);
	}
      if (dump_file && (dump_flags & TDF_DETAILS)
	  && !node->alias && !node->thunk.thunk_p)
	fprintf (dump_file, "Marking all lattices of %s/%i as %s\n",
		 node->name (), node->order,
		 disable ? "BOTTOM" : "VARIABLE");
    }

  for (ie = node->indirect_calls; ie; ie = ie->next_callee)
    if (ie->indirect_info->polymorphic
        && ie->indirect_info->param_index >= 0)
      {
	gcc_checking_assert (ie->indirect_info->param_index >= 0);
	ipa_get_parm_lattices (info,
			       ie->indirect_info->param_index)->virt_call = 1;
      }
}

/* Return the result of a (possibly arithmetic) pass through jump function
   JFUNC on the constant value INPUT.  Return NULL_TREE if that cannot be
   determined or be considered an interprocedural invariant.  */

static tree
ipa_get_jf_pass_through_result (struct ipa_jump_func *jfunc, tree input)
{
  tree restype, res;

  gcc_checking_assert (is_gimple_ip_invariant (input));
  if (ipa_get_jf_pass_through_operation (jfunc) == NOP_EXPR)
    return input;

  if (TREE_CODE_CLASS (ipa_get_jf_pass_through_operation (jfunc))
      == tcc_comparison)
    restype = boolean_type_node;
  else
    restype = TREE_TYPE (input);
  res = fold_binary (ipa_get_jf_pass_through_operation (jfunc), restype,
		     input, ipa_get_jf_pass_through_operand (jfunc));

  if (res && !is_gimple_ip_invariant (res))
    return NULL_TREE;

  return res;
}

/* Return the result of an ancestor jump function JFUNC on the constant value
   INPUT.  Return NULL_TREE if that cannot be determined.  */

static tree
ipa_get_jf_ancestor_result (struct ipa_jump_func *jfunc, tree input)
{
  gcc_checking_assert (TREE_CODE (input) != TREE_BINFO);
  if (TREE_CODE (input) == ADDR_EXPR)
    {
      tree t = TREE_OPERAND (input, 0);
      t = build_ref_for_offset (EXPR_LOCATION (t), t,
				ipa_get_jf_ancestor_offset (jfunc),
				ptr_type_node, NULL, false);
      return build_fold_addr_expr (t);
    }
  else
    return NULL_TREE;
}

/* Determine whether JFUNC evaluates to a single known constant value and if
   so, return it.  Otherwise return NULL.  INFO describes the caller node or
   the one it is inlined to, so that pass-through jump functions can be
   evaluated.  */

tree
ipa_value_from_jfunc (struct ipa_node_params *info, struct ipa_jump_func *jfunc)
{
  if (jfunc->type == IPA_JF_CONST)
    return ipa_get_jf_constant (jfunc);
  else if (jfunc->type == IPA_JF_PASS_THROUGH
	   || jfunc->type == IPA_JF_ANCESTOR)
    {
      tree input;
      int idx;

      if (jfunc->type == IPA_JF_PASS_THROUGH)
	idx = ipa_get_jf_pass_through_formal_id (jfunc);
      else
	idx = ipa_get_jf_ancestor_formal_id (jfunc);

      if (info->ipcp_orig_node)
	input = info->known_csts[idx];
      else
	{
	  ipcp_lattice<tree> *lat;

	  if (!info->lattices
	      || idx >= ipa_get_param_count (info))
	    return NULL_TREE;
	  lat = ipa_get_scalar_lat (info, idx);
	  if (!lat->is_single_const ())
	    return NULL_TREE;
	  input = lat->values->value;
	}

      if (!input)
	return NULL_TREE;

      if (jfunc->type == IPA_JF_PASS_THROUGH)
	return ipa_get_jf_pass_through_result (jfunc, input);
      else
	return ipa_get_jf_ancestor_result (jfunc, input);
    }
  else
    return NULL_TREE;
}

/* Determie whether JFUNC evaluates to single known polymorphic context, given
   that INFO describes the caller node or the one it is inlined to, CS is the
   call graph edge corresponding to JFUNC and CSIDX index of the described
   parameter.  */

ipa_polymorphic_call_context
ipa_context_from_jfunc (ipa_node_params *info, cgraph_edge *cs, int csidx,
			ipa_jump_func *jfunc)
{
  ipa_edge_args *args = IPA_EDGE_REF (cs);
  ipa_polymorphic_call_context ctx;
  ipa_polymorphic_call_context *edge_ctx
    = cs ? ipa_get_ith_polymorhic_call_context (args, csidx) : NULL;

  if (edge_ctx && !edge_ctx->useless_p ())
    ctx = *edge_ctx;

  if (jfunc->type == IPA_JF_PASS_THROUGH
      || jfunc->type == IPA_JF_ANCESTOR)
    {
      ipa_polymorphic_call_context srcctx;
      int srcidx;
      bool type_preserved = true;
      if (jfunc->type == IPA_JF_PASS_THROUGH)
	{
	  if (ipa_get_jf_pass_through_operation (jfunc) != NOP_EXPR)
	    return ctx;
	  type_preserved = ipa_get_jf_pass_through_type_preserved (jfunc);
	  srcidx = ipa_get_jf_pass_through_formal_id (jfunc);
	}
      else
	{
	  type_preserved = ipa_get_jf_ancestor_type_preserved (jfunc);
	  srcidx = ipa_get_jf_ancestor_formal_id (jfunc);
	}
      if (info->ipcp_orig_node)
	{
	  if (info->known_contexts.exists ())
	    srcctx = info->known_contexts[srcidx];
	}
      else
	{
	  if (!info->lattices
	      || srcidx >= ipa_get_param_count (info))
	    return ctx;
	  ipcp_lattice<ipa_polymorphic_call_context> *lat;
	  lat = ipa_get_poly_ctx_lat (info, srcidx);
	  if (!lat->is_single_const ())
	    return ctx;
	  srcctx = lat->values->value;
	}
      if (srcctx.useless_p ())
	return ctx;
      if (jfunc->type == IPA_JF_ANCESTOR)
	srcctx.offset_by (ipa_get_jf_ancestor_offset (jfunc));
      if (!type_preserved)
	srcctx.possible_dynamic_type_change (cs->in_polymorphic_cdtor);
      srcctx.combine_with (ctx);
      return srcctx;
    }

  return ctx;
}

/* If checking is enabled, verify that no lattice is in the TOP state, i.e. not
   bottom, not containing a variable component and without any known value at
   the same time.  */

DEBUG_FUNCTION void
ipcp_verify_propagated_values (void)
{
  struct cgraph_node *node;

  FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (node)
    {
      struct ipa_node_params *info = IPA_NODE_REF (node);
      int i, count = ipa_get_param_count (info);

      for (i = 0; i < count; i++)
	{
	  ipcp_lattice<tree> *lat = ipa_get_scalar_lat (info, i);

	  if (!lat->bottom
	      && !lat->contains_variable
	      && lat->values_count == 0)
	    {
	      if (dump_file)
		{
		  symtab_node::dump_table (dump_file);
		  fprintf (dump_file, "\nIPA lattices after constant "
			   "propagation, before gcc_unreachable:\n");
		  print_all_lattices (dump_file, true, false);
		}

	      gcc_unreachable ();
	    }
	}
    }
}

/* Return true iff X and Y should be considered equal values by IPA-CP.  */

static bool
values_equal_for_ipcp_p (tree x, tree y)
{
  gcc_checking_assert (x != NULL_TREE && y != NULL_TREE);

  if (x == y)
    return true;

  if (TREE_CODE (x) ==  ADDR_EXPR
      && TREE_CODE (y) ==  ADDR_EXPR
      && TREE_CODE (TREE_OPERAND (x, 0)) == CONST_DECL
      && TREE_CODE (TREE_OPERAND (y, 0)) == CONST_DECL)
    return operand_equal_p (DECL_INITIAL (TREE_OPERAND (x, 0)),
			    DECL_INITIAL (TREE_OPERAND (y, 0)), 0);
  else
    return operand_equal_p (x, y, 0);
}

/* Return true iff X and Y should be considered equal contexts by IPA-CP.  */

static bool
values_equal_for_ipcp_p (ipa_polymorphic_call_context x,
			 ipa_polymorphic_call_context y)
{
  return x.equal_to (y);
}


/* Add a new value source to the value represented by THIS, marking that a
   value comes from edge CS and (if the underlying jump function is a
   pass-through or an ancestor one) from a caller value SRC_VAL of a caller
   parameter described by SRC_INDEX.  OFFSET is negative if the source was the
   scalar value of the parameter itself or the offset within an aggregate.  */

template <typename valtype>
void
ipcp_value<valtype>::add_source (cgraph_edge *cs, ipcp_value *src_val,
				 int src_idx, HOST_WIDE_INT offset)
{
  ipcp_value_source<valtype> *src;

  src = new (pool_alloc (ipcp_sources_pool)) ipcp_value_source<valtype>;
  src->offset = offset;
  src->cs = cs;
  src->val = src_val;
  src->index = src_idx;

  src->next = sources;
  sources = src;
}

/* Allocate a new ipcp_value holding a tree constant, initialize its value to
   SOURCE and clear all other fields.  */

static ipcp_value<tree> *
allocate_and_init_ipcp_value (tree source)
{
  ipcp_value<tree> *val;

  val = new (pool_alloc (ipcp_cst_values_pool)) ipcp_value<tree>;
  memset (val, 0, sizeof (*val));
  val->value = source;
  return val;
}

/* Allocate a new ipcp_value holding a polymorphic context, initialize its
   value to SOURCE and clear all other fields.  */

static ipcp_value<ipa_polymorphic_call_context> *
allocate_and_init_ipcp_value (ipa_polymorphic_call_context source)
{
  ipcp_value<ipa_polymorphic_call_context> *val;

  val = new (pool_alloc (ipcp_poly_ctx_values_pool))
    ipcp_value<ipa_polymorphic_call_context>;
  memset (val, 0, sizeof (*val));
  val->value = source;
  return val;
}

/* Try to add NEWVAL to LAT, potentially creating a new ipcp_value for it.  CS,
   SRC_VAL SRC_INDEX and OFFSET are meant for add_source and have the same
   meaning.  OFFSET -1 means the source is scalar and not a part of an
   aggregate.  */

template <typename valtype>
bool
ipcp_lattice<valtype>::add_value (valtype newval, cgraph_edge *cs,
				  ipcp_value<valtype> *src_val,
				  int src_idx, HOST_WIDE_INT offset)
{
  ipcp_value<valtype> *val;

  if (bottom)
    return false;

  for (val = values; val; val = val->next)
    if (values_equal_for_ipcp_p (val->value, newval))
      {
	if (ipa_edge_within_scc (cs))
	  {
	    ipcp_value_source<valtype> *s;
	    for (s = val->sources; s ; s = s->next)
	      if (s->cs == cs)
		break;
	    if (s)
	      return false;
	  }

	val->add_source (cs, src_val, src_idx, offset);
	return false;
      }

  if (values_count == PARAM_VALUE (PARAM_IPA_CP_VALUE_LIST_SIZE))
    {
      /* We can only free sources, not the values themselves, because sources
	 of other values in this this SCC might point to them.   */
      for (val = values; val; val = val->next)
	{
	  while (val->sources)
	    {
	      ipcp_value_source<valtype> *src = val->sources;
	      val->sources = src->next;
	      pool_free (ipcp_sources_pool, src);
	    }
	}

      values = NULL;
      return set_to_bottom ();
    }

  values_count++;
  val = allocate_and_init_ipcp_value (newval);
  val->add_source (cs, src_val, src_idx, offset);
  val->next = values;
  values = val;
  return true;
}

/* Propagate values through a pass-through jump function JFUNC associated with
   edge CS, taking values from SRC_LAT and putting them into DEST_LAT.  SRC_IDX
   is the index of the source parameter.  */

static bool
propagate_vals_accross_pass_through (cgraph_edge *cs,
				     ipa_jump_func *jfunc,
				     ipcp_lattice<tree> *src_lat,
				     ipcp_lattice<tree> *dest_lat,
				     int src_idx)
{
  ipcp_value<tree> *src_val;
  bool ret = false;

  /* Do not create new values when propagating within an SCC because if there
     are arithmetic functions with circular dependencies, there is infinite
     number of them and we would just make lattices bottom.  */
  if ((ipa_get_jf_pass_through_operation (jfunc) != NOP_EXPR)
      && ipa_edge_within_scc (cs))
    ret = dest_lat->set_contains_variable ();
  else
    for (src_val = src_lat->values; src_val; src_val = src_val->next)
      {
	tree cstval = ipa_get_jf_pass_through_result (jfunc, src_val->value);

	if (cstval)
	  ret |= dest_lat->add_value (cstval, cs, src_val, src_idx);
	else
	  ret |= dest_lat->set_contains_variable ();
      }

  return ret;
}

/* Propagate values through an ancestor jump function JFUNC associated with
   edge CS, taking values from SRC_LAT and putting them into DEST_LAT.  SRC_IDX
   is the index of the source parameter.  */

static bool
propagate_vals_accross_ancestor (struct cgraph_edge *cs,
				 struct ipa_jump_func *jfunc,
				 ipcp_lattice<tree> *src_lat,
				 ipcp_lattice<tree> *dest_lat,
				 int src_idx)
{
  ipcp_value<tree> *src_val;
  bool ret = false;

  if (ipa_edge_within_scc (cs))
    return dest_lat->set_contains_variable ();

  for (src_val = src_lat->values; src_val; src_val = src_val->next)
    {
      tree t = ipa_get_jf_ancestor_result (jfunc, src_val->value);

      if (t)
	ret |= dest_lat->add_value (t, cs, src_val, src_idx);
      else
	ret |= dest_lat->set_contains_variable ();
    }

  return ret;
}

/* Propagate scalar values across jump function JFUNC that is associated with
   edge CS and put the values into DEST_LAT.  */

static bool
propagate_scalar_accross_jump_function (struct cgraph_edge *cs,
					struct ipa_jump_func *jfunc,
					ipcp_lattice<tree> *dest_lat)
{
  if (dest_lat->bottom)
    return false;

  if (jfunc->type == IPA_JF_CONST)
    {
      tree val = ipa_get_jf_constant (jfunc);
      return dest_lat->add_value (val, cs, NULL, 0);
    }
  else if (jfunc->type == IPA_JF_PASS_THROUGH
	   || jfunc->type == IPA_JF_ANCESTOR)
    {
      struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
      ipcp_lattice<tree> *src_lat;
      int src_idx;
      bool ret;

      if (jfunc->type == IPA_JF_PASS_THROUGH)
	src_idx = ipa_get_jf_pass_through_formal_id (jfunc);
      else
	src_idx = ipa_get_jf_ancestor_formal_id (jfunc);

      src_lat = ipa_get_scalar_lat (caller_info, src_idx);
      if (src_lat->bottom)
	return dest_lat->set_contains_variable ();

      /* If we would need to clone the caller and cannot, do not propagate.  */
      if (!ipcp_versionable_function_p (cs->caller)
	  && (src_lat->contains_variable
	      || (src_lat->values_count > 1)))
	return dest_lat->set_contains_variable ();

      if (jfunc->type == IPA_JF_PASS_THROUGH)
	ret = propagate_vals_accross_pass_through (cs, jfunc, src_lat,
						   dest_lat, src_idx);
      else
	ret = propagate_vals_accross_ancestor (cs, jfunc, src_lat, dest_lat,
					       src_idx);

      if (src_lat->contains_variable)
	ret |= dest_lat->set_contains_variable ();

      return ret;
    }

  /* TODO: We currently do not handle member method pointers in IPA-CP (we only
     use it for indirect inlining), we should propagate them too.  */
  return dest_lat->set_contains_variable ();
}

/* Propagate scalar values across jump function JFUNC that is associated with
   edge CS and describes argument IDX and put the values into DEST_LAT.  */

static bool
propagate_context_accross_jump_function (cgraph_edge *cs,
			  ipa_jump_func *jfunc, int idx,
			  ipcp_lattice<ipa_polymorphic_call_context> *dest_lat)
{
  ipa_edge_args *args = IPA_EDGE_REF (cs);
  if (dest_lat->bottom)
    return false;
  bool ret = false;
  bool added_sth = false;
  bool type_preserved = true;

  ipa_polymorphic_call_context edge_ctx, *edge_ctx_ptr
    = ipa_get_ith_polymorhic_call_context (args, idx);

  if (edge_ctx_ptr)
    edge_ctx = *edge_ctx_ptr;

  if (jfunc->type == IPA_JF_PASS_THROUGH
      || jfunc->type == IPA_JF_ANCESTOR)
    {
      struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
      int src_idx;
      ipcp_lattice<ipa_polymorphic_call_context> *src_lat;

      /* TODO: Once we figure out how to propagate speculations, it will
	 probably be a good idea to switch to speculation if type_preserved is
	 not set instead of punting.  */
      if (jfunc->type == IPA_JF_PASS_THROUGH)
	{
	  if (ipa_get_jf_pass_through_operation (jfunc) != NOP_EXPR)
	    goto prop_fail;
	  type_preserved = ipa_get_jf_pass_through_type_preserved (jfunc);
	  src_idx = ipa_get_jf_pass_through_formal_id (jfunc);
	}
      else
	{
	  type_preserved = ipa_get_jf_ancestor_type_preserved (jfunc);
	  src_idx = ipa_get_jf_ancestor_formal_id (jfunc);
	}

      src_lat = ipa_get_poly_ctx_lat (caller_info, src_idx);
      /* If we would need to clone the caller and cannot, do not propagate.  */
      if (!ipcp_versionable_function_p (cs->caller)
	  && (src_lat->contains_variable
	      || (src_lat->values_count > 1)))
	goto prop_fail;

      ipcp_value<ipa_polymorphic_call_context> *src_val;
      for (src_val = src_lat->values; src_val; src_val = src_val->next)
	{
	  ipa_polymorphic_call_context cur = src_val->value;

	  if (!type_preserved)
	    cur.possible_dynamic_type_change (cs->in_polymorphic_cdtor);
	  if (jfunc->type == IPA_JF_ANCESTOR)
	    cur.offset_by (ipa_get_jf_ancestor_offset (jfunc));
	  /* TODO: In cases we know how the context is going to be used,
	     we can improve the result by passing proper OTR_TYPE.  */
	  cur.combine_with (edge_ctx);
	  if (!cur.useless_p ())
	    {
	      if (src_lat->contains_variable
		  && !edge_ctx.equal_to (cur))
		ret |= dest_lat->set_contains_variable ();
	      ret |= dest_lat->add_value (cur, cs, src_val, src_idx);
	      added_sth = true;
	    }
	}

    }

 prop_fail:
  if (!added_sth)
    {
      if (!edge_ctx.useless_p ())
	ret |= dest_lat->add_value (edge_ctx, cs);
      else
	ret |= dest_lat->set_contains_variable ();
    }

  return ret;
}

/* Propagate alignments across jump function JFUNC that is associated with
   edge CS and update DEST_LAT accordingly.  */

static bool
propagate_alignment_accross_jump_function (struct cgraph_edge *cs,
					   struct ipa_jump_func *jfunc,
					   struct ipcp_param_lattices *dest_lat)
{
  if (alignment_bottom_p (dest_lat))
    return false;

  ipa_alignment cur;
  cur.known = false;
  if (jfunc->alignment.known)
    cur = jfunc->alignment;
  else if (jfunc->type == IPA_JF_PASS_THROUGH
	   || jfunc->type == IPA_JF_ANCESTOR)
    {
      struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
      struct ipcp_param_lattices *src_lats;
      HOST_WIDE_INT offset = 0;
      int src_idx;

      if (jfunc->type == IPA_JF_PASS_THROUGH)
	{
	  enum tree_code op = ipa_get_jf_pass_through_operation (jfunc);
	  if (op != NOP_EXPR)
	    {
	      if (op != POINTER_PLUS_EXPR
		  && op != PLUS_EXPR)
		goto prop_fail;
	      tree operand = ipa_get_jf_pass_through_operand (jfunc);
	      if (!tree_fits_shwi_p (operand))
		goto prop_fail;
	      offset = tree_to_shwi (operand);
	    }
	  src_idx = ipa_get_jf_pass_through_formal_id (jfunc);
	}
      else
	{
	  src_idx = ipa_get_jf_ancestor_formal_id (jfunc);
	  offset = ipa_get_jf_ancestor_offset (jfunc) / BITS_PER_UNIT;;
	}

      src_lats = ipa_get_parm_lattices (caller_info, src_idx);
      if (!src_lats->alignment.known
	  || alignment_bottom_p (src_lats))
	goto prop_fail;

      cur = src_lats->alignment;
      cur.misalign = (cur.misalign + offset) % cur.align;
    }

  if (cur.known)
    {
      if (!dest_lat->alignment.known)
	{
	  dest_lat->alignment = cur;
	  return true;
	}
      else if (dest_lat->alignment.align == cur.align
	       && dest_lat->alignment.misalign == cur.misalign)
	return false;
    }

 prop_fail:
  set_alignment_to_bottom (dest_lat);
  return true;
}

/* If DEST_PLATS already has aggregate items, check that aggs_by_ref matches
   NEW_AGGS_BY_REF and if not, mark all aggs as bottoms and return true (in all
   other cases, return false).  If there are no aggregate items, set
   aggs_by_ref to NEW_AGGS_BY_REF.  */

static bool
set_check_aggs_by_ref (struct ipcp_param_lattices *dest_plats,
		       bool new_aggs_by_ref)
{
  if (dest_plats->aggs)
    {
      if (dest_plats->aggs_by_ref != new_aggs_by_ref)
	{
	  set_agg_lats_to_bottom (dest_plats);
	  return true;
	}
    }
  else
    dest_plats->aggs_by_ref = new_aggs_by_ref;
  return false;
}

/* Walk aggregate lattices in DEST_PLATS from ***AGLAT on, until ***aglat is an
   already existing lattice for the given OFFSET and SIZE, marking all skipped
   lattices as containing variable and checking for overlaps.  If there is no
   already existing lattice for the OFFSET and VAL_SIZE, create one, initialize
   it with offset, size and contains_variable to PRE_EXISTING, and return true,
   unless there are too many already.  If there are two many, return false.  If
   there are overlaps turn whole DEST_PLATS to bottom and return false.  If any
   skipped lattices were newly marked as containing variable, set *CHANGE to
   true.  */

static bool
merge_agg_lats_step (struct ipcp_param_lattices *dest_plats,
		     HOST_WIDE_INT offset, HOST_WIDE_INT val_size,
		     struct ipcp_agg_lattice ***aglat,
		     bool pre_existing, bool *change)
{
  gcc_checking_assert (offset >= 0);

  while (**aglat && (**aglat)->offset < offset)
    {
      if ((**aglat)->offset + (**aglat)->size > offset)
	{
	  set_agg_lats_to_bottom (dest_plats);
	  return false;
	}
      *change |= (**aglat)->set_contains_variable ();
      *aglat = &(**aglat)->next;
    }

  if (**aglat && (**aglat)->offset == offset)
    {
      if ((**aglat)->size != val_size
          || ((**aglat)->next
              && (**aglat)->next->offset < offset + val_size))
	{
	  set_agg_lats_to_bottom (dest_plats);
	  return false;
	}
      gcc_checking_assert (!(**aglat)->next
			   || (**aglat)->next->offset >= offset + val_size);
      return true;
    }
  else
    {
      struct ipcp_agg_lattice *new_al;

      if (**aglat && (**aglat)->offset < offset + val_size)
	{
	  set_agg_lats_to_bottom (dest_plats);
	  return false;
	}
      if (dest_plats->aggs_count == PARAM_VALUE (PARAM_IPA_MAX_AGG_ITEMS))
	return false;
      dest_plats->aggs_count++;
      new_al = (struct ipcp_agg_lattice *) pool_alloc (ipcp_agg_lattice_pool);
      memset (new_al, 0, sizeof (*new_al));

      new_al->offset = offset;
      new_al->size = val_size;
      new_al->contains_variable = pre_existing;

      new_al->next = **aglat;
      **aglat = new_al;
      return true;
    }
}

/* Set all AGLAT and all other aggregate lattices reachable by next pointers as
   containing an unknown value.  */

static bool
set_chain_of_aglats_contains_variable (struct ipcp_agg_lattice *aglat)
{
  bool ret = false;
  while (aglat)
    {
      ret |= aglat->set_contains_variable ();
      aglat = aglat->next;
    }
  return ret;
}

/* Merge existing aggregate lattices in SRC_PLATS to DEST_PLATS, subtracting
   DELTA_OFFSET.  CS is the call graph edge and SRC_IDX the index of the source
   parameter used for lattice value sources.  Return true if DEST_PLATS changed
   in any way.  */

static bool
merge_aggregate_lattices (struct cgraph_edge *cs,
			  struct ipcp_param_lattices *dest_plats,
			  struct ipcp_param_lattices *src_plats,
			  int src_idx, HOST_WIDE_INT offset_delta)
{
  bool pre_existing = dest_plats->aggs != NULL;
  struct ipcp_agg_lattice **dst_aglat;
  bool ret = false;

  if (set_check_aggs_by_ref (dest_plats, src_plats->aggs_by_ref))
    return true;
  if (src_plats->aggs_bottom)
    return set_agg_lats_contain_variable (dest_plats);
  if (src_plats->aggs_contain_variable)
    ret |= set_agg_lats_contain_variable (dest_plats);
  dst_aglat = &dest_plats->aggs;

  for (struct ipcp_agg_lattice *src_aglat = src_plats->aggs;
       src_aglat;
       src_aglat = src_aglat->next)
    {
      HOST_WIDE_INT new_offset = src_aglat->offset - offset_delta;

      if (new_offset < 0)
	continue;
      if (merge_agg_lats_step (dest_plats, new_offset, src_aglat->size,
			       &dst_aglat, pre_existing, &ret))
	{
	  struct ipcp_agg_lattice *new_al = *dst_aglat;

	  dst_aglat = &(*dst_aglat)->next;
	  if (src_aglat->bottom)
	    {
	      ret |= new_al->set_contains_variable ();
	      continue;
	    }
	  if (src_aglat->contains_variable)
	    ret |= new_al->set_contains_variable ();
	  for (ipcp_value<tree> *val = src_aglat->values;
	       val;
	       val = val->next)
	    ret |= new_al->add_value (val->value, cs, val, src_idx,
				      src_aglat->offset);
	}
      else if (dest_plats->aggs_bottom)
	return true;
    }
  ret |= set_chain_of_aglats_contains_variable (*dst_aglat);
  return ret;
}

/* Determine whether there is anything to propagate FROM SRC_PLATS through a
   pass-through JFUNC and if so, whether it has conform and conforms to the
   rules about propagating values passed by reference.  */

static bool
agg_pass_through_permissible_p (struct ipcp_param_lattices *src_plats,
				struct ipa_jump_func *jfunc)
{
  return src_plats->aggs
    && (!src_plats->aggs_by_ref
	|| ipa_get_jf_pass_through_agg_preserved (jfunc));
}

/* Propagate scalar values across jump function JFUNC that is associated with
   edge CS and put the values into DEST_LAT.  */

static bool
propagate_aggs_accross_jump_function (struct cgraph_edge *cs,
				      struct ipa_jump_func *jfunc,
				      struct ipcp_param_lattices *dest_plats)
{
  bool ret = false;

  if (dest_plats->aggs_bottom)
    return false;

  if (jfunc->type == IPA_JF_PASS_THROUGH
      && ipa_get_jf_pass_through_operation (jfunc) == NOP_EXPR)
    {
      struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
      int src_idx = ipa_get_jf_pass_through_formal_id (jfunc);
      struct ipcp_param_lattices *src_plats;

      src_plats = ipa_get_parm_lattices (caller_info, src_idx);
      if (agg_pass_through_permissible_p (src_plats, jfunc))
	{
	  /* Currently we do not produce clobber aggregate jump
	     functions, replace with merging when we do.  */
	  gcc_assert (!jfunc->agg.items);
	  ret |= merge_aggregate_lattices (cs, dest_plats, src_plats,
					   src_idx, 0);
	}
      else
	ret |= set_agg_lats_contain_variable (dest_plats);
    }
  else if (jfunc->type == IPA_JF_ANCESTOR
	   && ipa_get_jf_ancestor_agg_preserved (jfunc))
    {
      struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
      int src_idx = ipa_get_jf_ancestor_formal_id (jfunc);
      struct ipcp_param_lattices *src_plats;

      src_plats = ipa_get_parm_lattices (caller_info, src_idx);
      if (src_plats->aggs && src_plats->aggs_by_ref)
	{
	  /* Currently we do not produce clobber aggregate jump
	     functions, replace with merging when we do.  */
	  gcc_assert (!jfunc->agg.items);
	  ret |= merge_aggregate_lattices (cs, dest_plats, src_plats, src_idx,
					   ipa_get_jf_ancestor_offset (jfunc));
	}
      else if (!src_plats->aggs_by_ref)
	ret |= set_agg_lats_to_bottom (dest_plats);
      else
	ret |= set_agg_lats_contain_variable (dest_plats);
    }
  else if (jfunc->agg.items)
    {
      bool pre_existing = dest_plats->aggs != NULL;
      struct ipcp_agg_lattice **aglat = &dest_plats->aggs;
      struct ipa_agg_jf_item *item;
      int i;

      if (set_check_aggs_by_ref (dest_plats, jfunc->agg.by_ref))
	return true;

      FOR_EACH_VEC_ELT (*jfunc->agg.items, i, item)
	{
	  HOST_WIDE_INT val_size;

	  if (item->offset < 0)
	    continue;
	  gcc_checking_assert (is_gimple_ip_invariant (item->value));
	  val_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (item->value)));

	  if (merge_agg_lats_step (dest_plats, item->offset, val_size,
				   &aglat, pre_existing, &ret))
	    {
	      ret |= (*aglat)->add_value (item->value, cs, NULL, 0, 0);
	      aglat = &(*aglat)->next;
	    }
	  else if (dest_plats->aggs_bottom)
	    return true;
	}

      ret |= set_chain_of_aglats_contains_variable (*aglat);
    }
  else
    ret |= set_agg_lats_contain_variable (dest_plats);

  return ret;
}

/* Return true if on the way cfrom CS->caller to the final (non-alias and
   non-thunk) destination, the call passes through a thunk.  */

static bool
call_passes_through_thunk_p (cgraph_edge *cs)
{
  cgraph_node *alias_or_thunk = cs->callee;
  while (alias_or_thunk->alias)
    alias_or_thunk = alias_or_thunk->get_alias_target ();
  return alias_or_thunk->thunk.thunk_p;
}

/* Propagate constants from the caller to the callee of CS.  INFO describes the
   caller.  */

static bool
propagate_constants_accross_call (struct cgraph_edge *cs)
{
  struct ipa_node_params *callee_info;
  enum availability availability;
  cgraph_node *callee;
  struct ipa_edge_args *args;
  bool ret = false;
  int i, args_count, parms_count;

  callee = cs->callee->function_symbol (&availability);
  if (!callee->definition)
    return false;
  gcc_checking_assert (callee->has_gimple_body_p ());
  callee_info = IPA_NODE_REF (callee);

  args = IPA_EDGE_REF (cs);
  args_count = ipa_get_cs_argument_count (args);
  parms_count = ipa_get_param_count (callee_info);
  if (parms_count == 0)
    return false;

  /* No propagation through instrumentation thunks is available yet.
     It should be possible with proper mapping of call args and
     instrumented callee params in the propagation loop below.  But
     this case mostly occurs when legacy code calls instrumented code
     and it is not a primary target for optimizations.
     We detect instrumentation thunks in aliases and thunks chain by
     checking instrumentation_clone flag for chain source and target.
     Going through instrumentation thunks we always have it changed
     from 0 to 1 and all other nodes do not change it.  */
  if (!cs->callee->instrumentation_clone
      && callee->instrumentation_clone)
    {
      for (i = 0; i < parms_count; i++)
	ret |= set_all_contains_variable (ipa_get_parm_lattices (callee_info,
								 i));
      return ret;
    }

  /* If this call goes through a thunk we must not propagate to the first (0th)
     parameter.  However, we might need to uncover a thunk from below a series
     of aliases first.  */
  if (call_passes_through_thunk_p (cs))
    {
      ret |= set_all_contains_variable (ipa_get_parm_lattices (callee_info,
							       0));
      i = 1;
    }
  else
    i = 0;

  for (; (i < args_count) && (i < parms_count); i++)
    {
      struct ipa_jump_func *jump_func = ipa_get_ith_jump_func (args, i);
      struct ipcp_param_lattices *dest_plats;

      dest_plats = ipa_get_parm_lattices (callee_info, i);
      if (availability == AVAIL_INTERPOSABLE)
	ret |= set_all_contains_variable (dest_plats);
      else
	{
	  ret |= propagate_scalar_accross_jump_function (cs, jump_func,
							 &dest_plats->itself);
	  ret |= propagate_context_accross_jump_function (cs, jump_func, i,
							  &dest_plats->ctxlat);
	  ret |= propagate_alignment_accross_jump_function (cs, jump_func,
							    dest_plats);
	  ret |= propagate_aggs_accross_jump_function (cs, jump_func,
						       dest_plats);
	}
    }
  for (; i < parms_count; i++)
    ret |= set_all_contains_variable (ipa_get_parm_lattices (callee_info, i));

  return ret;
}

/* If an indirect edge IE can be turned into a direct one based on KNOWN_VALS
   KNOWN_CONTEXTS, KNOWN_AGGS or AGG_REPS return the destination.  The latter
   three can be NULL.  If AGG_REPS is not NULL, KNOWN_AGGS is ignored.  */

static tree
ipa_get_indirect_edge_target_1 (struct cgraph_edge *ie,
				vec<tree> known_csts,
				vec<ipa_polymorphic_call_context> known_contexts,
				vec<ipa_agg_jump_function_p> known_aggs,
				struct ipa_agg_replacement_value *agg_reps,
				bool *speculative)
{
  int param_index = ie->indirect_info->param_index;
  HOST_WIDE_INT anc_offset;
  tree t;
  tree target = NULL;

  *speculative = false;

  if (param_index == -1
      || known_csts.length () <= (unsigned int) param_index)
    return NULL_TREE;

  if (!ie->indirect_info->polymorphic)
    {
      tree t;

      if (ie->indirect_info->agg_contents)
	{
	  if (agg_reps)
	    {
	      t = NULL;
	      while (agg_reps)
		{
		  if (agg_reps->index == param_index
		      && agg_reps->offset == ie->indirect_info->offset
		      && agg_reps->by_ref == ie->indirect_info->by_ref)
		    {
		      t = agg_reps->value;
		      break;
		    }
		  agg_reps = agg_reps->next;
		}
	    }
	  else if (known_aggs.length () > (unsigned int) param_index)
	    {
	      struct ipa_agg_jump_function *agg;
	      agg = known_aggs[param_index];
	      t = ipa_find_agg_cst_for_param (agg, ie->indirect_info->offset,
					      ie->indirect_info->by_ref);
	    }
	  else
	    t = NULL;
	}
      else
	t = known_csts[param_index];

      if (t &&
	  TREE_CODE (t) == ADDR_EXPR
	  && TREE_CODE (TREE_OPERAND (t, 0)) == FUNCTION_DECL)
	return TREE_OPERAND (t, 0);
      else
	return NULL_TREE;
    }

  if (!opt_for_fn (ie->caller->decl, flag_devirtualize))
    return NULL_TREE;

  gcc_assert (!ie->indirect_info->agg_contents);
  anc_offset = ie->indirect_info->offset;

  t = NULL;

  /* Try to work out value of virtual table pointer value in replacemnets.  */
  if (!t && agg_reps && !ie->indirect_info->by_ref)
    {
      while (agg_reps)
	{
	  if (agg_reps->index == param_index
	      && agg_reps->offset == ie->indirect_info->offset
	      && agg_reps->by_ref)
	    {
	      t = agg_reps->value;
	      break;
	    }
	  agg_reps = agg_reps->next;
	}
    }

  /* Try to work out value of virtual table pointer value in known
     aggregate values.  */
  if (!t && known_aggs.length () > (unsigned int) param_index
      && !ie->indirect_info->by_ref)
    {
       struct ipa_agg_jump_function *agg;
       agg = known_aggs[param_index];
       t = ipa_find_agg_cst_for_param (agg, ie->indirect_info->offset,
				       true);
    }

  /* If we found the virtual table pointer, lookup the target.  */
  if (t)
    {
      tree vtable;
      unsigned HOST_WIDE_INT offset;
      if (vtable_pointer_value_to_vtable (t, &vtable, &offset))
	{
	  target = gimple_get_virt_method_for_vtable (ie->indirect_info->otr_token,
						      vtable, offset);
	  if (target)
	    {
	      if ((TREE_CODE (TREE_TYPE (target)) == FUNCTION_TYPE
		   && DECL_FUNCTION_CODE (target) == BUILT_IN_UNREACHABLE)
		  || !possible_polymorphic_call_target_p
		       (ie, cgraph_node::get (target)))
		target = ipa_impossible_devirt_target (ie, target);
              *speculative = ie->indirect_info->vptr_changed;
	      if (!*speculative)
	        return target;
	    }
	}
    }

  /* Do we know the constant value of pointer?  */
  if (!t)
    t = known_csts[param_index];

  gcc_checking_assert (!t || TREE_CODE (t) != TREE_BINFO);

  ipa_polymorphic_call_context context;
  if (known_contexts.length () > (unsigned int) param_index)
    {
      context = known_contexts[param_index];
      context.offset_by (anc_offset);
      if (ie->indirect_info->vptr_changed)
	context.possible_dynamic_type_change (ie->in_polymorphic_cdtor,
					      ie->indirect_info->otr_type);
      if (t)
	{
	  ipa_polymorphic_call_context ctx2 = ipa_polymorphic_call_context
	    (t, ie->indirect_info->otr_type, anc_offset);
	  if (!ctx2.useless_p ())
	    context.combine_with (ctx2, ie->indirect_info->otr_type);
	}
    }
  else if (t)
    {
      context = ipa_polymorphic_call_context (t, ie->indirect_info->otr_type,
					      anc_offset);
      if (ie->indirect_info->vptr_changed)
	context.possible_dynamic_type_change (ie->in_polymorphic_cdtor,
					      ie->indirect_info->otr_type);
    }
  else
    return NULL_TREE;

  vec <cgraph_node *>targets;
  bool final;

  targets = possible_polymorphic_call_targets
    (ie->indirect_info->otr_type,
     ie->indirect_info->otr_token,
     context, &final);
  if (!final || targets.length () > 1)
    {
      struct cgraph_node *node;
      if (*speculative)
	return target;
      if (!opt_for_fn (ie->caller->decl, flag_devirtualize_speculatively)
	  || ie->speculative || !ie->maybe_hot_p ())
	return NULL;
      node = try_speculative_devirtualization (ie->indirect_info->otr_type,
					       ie->indirect_info->otr_token,
					       context);
      if (node)
	{
	  *speculative = true;
	  target = node->decl;
	}
      else
	return NULL;
    }
  else
    {
      *speculative = false;
      if (targets.length () == 1)
	target = targets[0]->decl;
      else
	target = ipa_impossible_devirt_target (ie, NULL_TREE);
    }

  if (target && !possible_polymorphic_call_target_p (ie,
						     cgraph_node::get (target)))
    target = ipa_impossible_devirt_target (ie, target);

  return target;
}


/* If an indirect edge IE can be turned into a direct one based on KNOWN_CSTS,
   KNOWN_CONTEXTS (which can be vNULL) or KNOWN_AGGS (which also can be vNULL)
   return the destination.  */

tree
ipa_get_indirect_edge_target (struct cgraph_edge *ie,
			      vec<tree> known_csts,
			      vec<ipa_polymorphic_call_context> known_contexts,
			      vec<ipa_agg_jump_function_p> known_aggs,
			      bool *speculative)
{
  return ipa_get_indirect_edge_target_1 (ie, known_csts, known_contexts,
					 known_aggs, NULL, speculative);
}

/* Calculate devirtualization time bonus for NODE, assuming we know KNOWN_CSTS
   and KNOWN_CONTEXTS.  */

static int
devirtualization_time_bonus (struct cgraph_node *node,
			     vec<tree> known_csts,
			     vec<ipa_polymorphic_call_context> known_contexts,
			     vec<ipa_agg_jump_function_p> known_aggs)
{
  struct cgraph_edge *ie;
  int res = 0;

  for (ie = node->indirect_calls; ie; ie = ie->next_callee)
    {
      struct cgraph_node *callee;
      struct inline_summary *isummary;
      enum availability avail;
      tree target;
      bool speculative;

      target = ipa_get_indirect_edge_target (ie, known_csts, known_contexts,
					     known_aggs, &speculative);
      if (!target)
	continue;

      /* Only bare minimum benefit for clearly un-inlineable targets.  */
      res += 1;
      callee = cgraph_node::get (target);
      if (!callee || !callee->definition)
	continue;
      callee = callee->function_symbol (&avail);
      if (avail < AVAIL_AVAILABLE)
	continue;
      isummary = inline_summaries->get (callee);
      if (!isummary->inlinable)
	continue;

      /* FIXME: The values below need re-considering and perhaps also
	 integrating into the cost metrics, at lest in some very basic way.  */
      if (isummary->size <= MAX_INLINE_INSNS_AUTO / 4)
	res += 31 / ((int)speculative + 1);
      else if (isummary->size <= MAX_INLINE_INSNS_AUTO / 2)
	res += 15 / ((int)speculative + 1);
      else if (isummary->size <= MAX_INLINE_INSNS_AUTO
	       || DECL_DECLARED_INLINE_P (callee->decl))
	res += 7 / ((int)speculative + 1);
    }

  return res;
}

/* Return time bonus incurred because of HINTS.  */

static int
hint_time_bonus (inline_hints hints)
{
  int result = 0;
  if (hints & (INLINE_HINT_loop_iterations | INLINE_HINT_loop_stride))
    result += PARAM_VALUE (PARAM_IPA_CP_LOOP_HINT_BONUS);
  if (hints & INLINE_HINT_array_index)
    result += PARAM_VALUE (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS);
  return result;
}

/* If there is a reason to penalize the function described by INFO in the
   cloning goodness evaluation, do so.  */

static inline int64_t
incorporate_penalties (ipa_node_params *info, int64_t evaluation)
{
  if (info->node_within_scc)
    evaluation = (evaluation
		  * (100 - PARAM_VALUE (PARAM_IPA_CP_RECURSION_PENALTY))) / 100;

  if (info->node_calling_single_call)
    evaluation = (evaluation
		  * (100 - PARAM_VALUE (PARAM_IPA_CP_SINGLE_CALL_PENALTY)))
      / 100;

  return evaluation;
}

/* Return true if cloning NODE is a good idea, given the estimated TIME_BENEFIT
   and SIZE_COST and with the sum of frequencies of incoming edges to the
   potential new clone in FREQUENCIES.  */

static bool
good_cloning_opportunity_p (struct cgraph_node *node, int time_benefit,
			    int freq_sum, gcov_type count_sum, int size_cost)
{
  if (time_benefit == 0
      || !opt_for_fn (node->decl, flag_ipa_cp_clone)
      || !optimize_function_for_speed_p (DECL_STRUCT_FUNCTION (node->decl)))
    return false;

  gcc_assert (size_cost > 0);

  struct ipa_node_params *info = IPA_NODE_REF (node);
  if (max_count)
    {
      int factor = (count_sum * 1000) / max_count;
      int64_t evaluation = (((int64_t) time_benefit * factor)
				    / size_cost);
      evaluation = incorporate_penalties (info, evaluation);

      if (dump_file && (dump_flags & TDF_DETAILS))
	fprintf (dump_file, "     good_cloning_opportunity_p (time: %i, "
		 "size: %i, count_sum: " HOST_WIDE_INT_PRINT_DEC
		 "%s%s) -> evaluation: " "%"PRId64
		 ", threshold: %i\n",
		 time_benefit, size_cost, (HOST_WIDE_INT) count_sum,
		 info->node_within_scc ? ", scc" : "",
		 info->node_calling_single_call ? ", single_call" : "",
		 evaluation, PARAM_VALUE (PARAM_IPA_CP_EVAL_THRESHOLD));

      return evaluation >= PARAM_VALUE (PARAM_IPA_CP_EVAL_THRESHOLD);
    }
  else
    {
      int64_t evaluation = (((int64_t) time_benefit * freq_sum)
				    / size_cost);
      evaluation = incorporate_penalties (info, evaluation);

      if (dump_file && (dump_flags & TDF_DETAILS))
	fprintf (dump_file, "     good_cloning_opportunity_p (time: %i, "
		 "size: %i, freq_sum: %i%s%s) -> evaluation: "
		 "%"PRId64 ", threshold: %i\n",
		 time_benefit, size_cost, freq_sum,
		 info->node_within_scc ? ", scc" : "",
		 info->node_calling_single_call ? ", single_call" : "",
		 evaluation, PARAM_VALUE (PARAM_IPA_CP_EVAL_THRESHOLD));

      return evaluation >= PARAM_VALUE (PARAM_IPA_CP_EVAL_THRESHOLD);
    }
}

/* Return all context independent values from aggregate lattices in PLATS in a
   vector.  Return NULL if there are none.  */

static vec<ipa_agg_jf_item, va_gc> *
context_independent_aggregate_values (struct ipcp_param_lattices *plats)
{
  vec<ipa_agg_jf_item, va_gc> *res = NULL;

  if (plats->aggs_bottom
      || plats->aggs_contain_variable
      || plats->aggs_count == 0)
    return NULL;

  for (struct ipcp_agg_lattice *aglat = plats->aggs;
       aglat;
       aglat = aglat->next)
    if (aglat->is_single_const ())
      {
	struct ipa_agg_jf_item item;
	item.offset = aglat->offset;
	item.value = aglat->values->value;
	vec_safe_push (res, item);
      }
  return res;
}

/* Allocate KNOWN_CSTS, KNOWN_CONTEXTS and, if non-NULL, KNOWN_AGGS and
   populate them with values of parameters that are known independent of the
   context.  INFO describes the function.  If REMOVABLE_PARAMS_COST is
   non-NULL, the movement cost of all removable parameters will be stored in
   it.  */

static bool
gather_context_independent_values (struct ipa_node_params *info,
				   vec<tree> *known_csts,
				   vec<ipa_polymorphic_call_context>
				   *known_contexts,
				   vec<ipa_agg_jump_function> *known_aggs,
				   int *removable_params_cost)
{
  int i, count = ipa_get_param_count (info);
  bool ret = false;

  known_csts->create (0);
  known_contexts->create (0);
  known_csts->safe_grow_cleared (count);
  known_contexts->safe_grow_cleared (count);
  if (known_aggs)
    {
      known_aggs->create (0);
      known_aggs->safe_grow_cleared (count);
    }

  if (removable_params_cost)
    *removable_params_cost = 0;

  for (i = 0; i < count ; i++)
    {
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
      ipcp_lattice<tree> *lat = &plats->itself;

      if (lat->is_single_const ())
	{
	  ipcp_value<tree> *val = lat->values;
	  gcc_checking_assert (TREE_CODE (val->value) != TREE_BINFO);
	  (*known_csts)[i] = val->value;
	  if (removable_params_cost)
	    *removable_params_cost
	      += estimate_move_cost (TREE_TYPE (val->value), false);
	  ret = true;
	}
      else if (removable_params_cost
	       && !ipa_is_param_used (info, i))
	*removable_params_cost
	  += ipa_get_param_move_cost (info, i);

      ipcp_lattice<ipa_polymorphic_call_context> *ctxlat = &plats->ctxlat;
      if (ctxlat->is_single_const ())
	{
	  (*known_contexts)[i] = ctxlat->values->value;
	  ret = true;
	}

      if (known_aggs)
	{
	  vec<ipa_agg_jf_item, va_gc> *agg_items;
	  struct ipa_agg_jump_function *ajf;

	  agg_items = context_independent_aggregate_values (plats);
	  ajf = &(*known_aggs)[i];
	  ajf->items = agg_items;
	  ajf->by_ref = plats->aggs_by_ref;
	  ret |= agg_items != NULL;
	}
    }

  return ret;
}

/* The current interface in ipa-inline-analysis requires a pointer vector.
   Create it.

   FIXME: That interface should be re-worked, this is slightly silly.  Still,
   I'd like to discuss how to change it first and this demonstrates the
   issue.  */

static vec<ipa_agg_jump_function_p>
agg_jmp_p_vec_for_t_vec (vec<ipa_agg_jump_function> known_aggs)
{
  vec<ipa_agg_jump_function_p> ret;
  struct ipa_agg_jump_function *ajf;
  int i;

  ret.create (known_aggs.length ());
  FOR_EACH_VEC_ELT (known_aggs, i, ajf)
    ret.quick_push (ajf);
  return ret;
}

/* Perform time and size measurement of NODE with the context given in
   KNOWN_CSTS, KNOWN_CONTEXTS and KNOWN_AGGS, calculate the benefit and cost
   given BASE_TIME of the node without specialization, REMOVABLE_PARAMS_COST of
   all context-independent removable parameters and EST_MOVE_COST of estimated
   movement of the considered parameter and store it into VAL.  */

static void
perform_estimation_of_a_value (cgraph_node *node, vec<tree> known_csts,
			       vec<ipa_polymorphic_call_context> known_contexts,
			       vec<ipa_agg_jump_function_p> known_aggs_ptrs,
			       int base_time, int removable_params_cost,
			       int est_move_cost, ipcp_value_base *val)
{
  int time, size, time_benefit;
  inline_hints hints;

  estimate_ipcp_clone_size_and_time (node, known_csts, known_contexts,
				     known_aggs_ptrs, &size, &time,
				     &hints);
  time_benefit = base_time - time
    + devirtualization_time_bonus (node, known_csts, known_contexts,
				   known_aggs_ptrs)
    + hint_time_bonus (hints)
    + removable_params_cost + est_move_cost;

  gcc_checking_assert (size >=0);
  /* The inliner-heuristics based estimates may think that in certain
     contexts some functions do not have any size at all but we want
     all specializations to have at least a tiny cost, not least not to
     divide by zero.  */
  if (size == 0)
    size = 1;

  val->local_time_benefit = time_benefit;
  val->local_size_cost = size;
}

/* Iterate over known values of parameters of NODE and estimate the local
   effects in terms of time and size they have.  */

static void
estimate_local_effects (struct cgraph_node *node)
{
  struct ipa_node_params *info = IPA_NODE_REF (node);
  int i, count = ipa_get_param_count (info);
  vec<tree> known_csts;
  vec<ipa_polymorphic_call_context> known_contexts;
  vec<ipa_agg_jump_function> known_aggs;
  vec<ipa_agg_jump_function_p> known_aggs_ptrs;
  bool always_const;
  int base_time = inline_summaries->get (node)->time;
  int removable_params_cost;

  if (!count || !ipcp_versionable_function_p (node))
    return;

  if (dump_file && (dump_flags & TDF_DETAILS))
    fprintf (dump_file, "\nEstimating effects for %s/%i, base_time: %i.\n",
	     node->name (), node->order, base_time);

  always_const = gather_context_independent_values (info, &known_csts,
						    &known_contexts, &known_aggs,
						    &removable_params_cost);
  known_aggs_ptrs = agg_jmp_p_vec_for_t_vec (known_aggs);
  if (always_const)
    {
      struct caller_statistics stats;
      inline_hints hints;
      int time, size;

      init_caller_stats (&stats);
      node->call_for_symbol_thunks_and_aliases (gather_caller_stats, &stats,
					      false);
      estimate_ipcp_clone_size_and_time (node, known_csts, known_contexts,
					 known_aggs_ptrs, &size, &time, &hints);
      time -= devirtualization_time_bonus (node, known_csts, known_contexts,
					   known_aggs_ptrs);
      time -= hint_time_bonus (hints);
      time -= removable_params_cost;
      size -= stats.n_calls * removable_params_cost;

      if (dump_file)
	fprintf (dump_file, " - context independent values, size: %i, "
		 "time_benefit: %i\n", size, base_time - time);

      if (size <= 0
	  || node->will_be_removed_from_program_if_no_direct_calls_p ())
	{
	  info->do_clone_for_all_contexts = true;
	  base_time = time;

	  if (dump_file)
	    fprintf (dump_file, "     Decided to specialize for all "
		     "known contexts, code not going to grow.\n");
	}
      else if (good_cloning_opportunity_p (node, base_time - time,
					   stats.freq_sum, stats.count_sum,
					   size))
	{
	  if (size + overall_size <= max_new_size)
	    {
	      info->do_clone_for_all_contexts = true;
	      base_time = time;
	      overall_size += size;

	      if (dump_file)
		fprintf (dump_file, "     Decided to specialize for all "
			 "known contexts, growth deemed beneficial.\n");
	    }
	  else if (dump_file && (dump_flags & TDF_DETAILS))
	    fprintf (dump_file, "   Not cloning for all contexts because "
		     "max_new_size would be reached with %li.\n",
		     size + overall_size);
	}
    }

  for (i = 0; i < count ; i++)
    {
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
      ipcp_lattice<tree> *lat = &plats->itself;
      ipcp_value<tree> *val;

      if (lat->bottom
	  || !lat->values
	  || known_csts[i])
	continue;

      for (val = lat->values; val; val = val->next)
	{
	  gcc_checking_assert (TREE_CODE (val->value) != TREE_BINFO);
	  known_csts[i] = val->value;

	  int emc = estimate_move_cost (TREE_TYPE (val->value), true);
	  perform_estimation_of_a_value (node, known_csts, known_contexts,
					 known_aggs_ptrs, base_time,
					 removable_params_cost, emc, val);

	  if (dump_file && (dump_flags & TDF_DETAILS))
	    {
	      fprintf (dump_file, " - estimates for value ");
	      print_ipcp_constant_value (dump_file, val->value);
	      fprintf (dump_file, " for ");
	      ipa_dump_param (dump_file, info, i);
	      fprintf (dump_file, ": time_benefit: %i, size: %i\n",
		       val->local_time_benefit, val->local_size_cost);
	    }
	}
      known_csts[i] = NULL_TREE;
    }

  for (i = 0; i < count; i++)
    {
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);

      if (!plats->virt_call)
	continue;

      ipcp_lattice<ipa_polymorphic_call_context> *ctxlat = &plats->ctxlat;
      ipcp_value<ipa_polymorphic_call_context> *val;

      if (ctxlat->bottom
	  || !ctxlat->values
	  || !known_contexts[i].useless_p ())
	continue;

      for (val = ctxlat->values; val; val = val->next)
	{
	  known_contexts[i] = val->value;
	  perform_estimation_of_a_value (node, known_csts, known_contexts,
					 known_aggs_ptrs, base_time,
					 removable_params_cost, 0, val);

	  if (dump_file && (dump_flags & TDF_DETAILS))
	    {
	      fprintf (dump_file, " - estimates for polymorphic context ");
	      print_ipcp_constant_value (dump_file, val->value);
	      fprintf (dump_file, " for ");
	      ipa_dump_param (dump_file, info, i);
	      fprintf (dump_file, ": time_benefit: %i, size: %i\n",
		       val->local_time_benefit, val->local_size_cost);
	    }
	}
      known_contexts[i] = ipa_polymorphic_call_context ();
    }

  for (i = 0; i < count ; i++)
    {
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
      struct ipa_agg_jump_function *ajf;
      struct ipcp_agg_lattice *aglat;

      if (plats->aggs_bottom || !plats->aggs)
	continue;

      ajf = &known_aggs[i];
      for (aglat = plats->aggs; aglat; aglat = aglat->next)
	{
	  ipcp_value<tree> *val;
	  if (aglat->bottom || !aglat->values
	      /* If the following is true, the one value is in known_aggs.  */
	      || (!plats->aggs_contain_variable
		  && aglat->is_single_const ()))
	    continue;

	  for (val = aglat->values; val; val = val->next)
	    {
	      struct ipa_agg_jf_item item;

	      item.offset = aglat->offset;
	      item.value = val->value;
	      vec_safe_push (ajf->items, item);

	      perform_estimation_of_a_value (node, known_csts, known_contexts,
					     known_aggs_ptrs, base_time,
					     removable_params_cost, 0, val);

	      if (dump_file && (dump_flags & TDF_DETAILS))
		{
		  fprintf (dump_file, " - estimates for value ");
		  print_ipcp_constant_value (dump_file, val->value);
		  fprintf (dump_file, " for ");
	          ipa_dump_param (dump_file, info, i);
		  fprintf (dump_file, "[%soffset: " HOST_WIDE_INT_PRINT_DEC
			   "]: time_benefit: %i, size: %i\n",
			   plats->aggs_by_ref ? "ref " : "",
			   aglat->offset,
			   val->local_time_benefit, val->local_size_cost);
		}

	      ajf->items->pop ();
	    }
	}
    }

  for (i = 0; i < count ; i++)
    vec_free (known_aggs[i].items);

  known_csts.release ();
  known_contexts.release ();
  known_aggs.release ();
  known_aggs_ptrs.release ();
}


/* Add value CUR_VAL and all yet-unsorted values it is dependent on to the
   topological sort of values.  */

template <typename valtype>
void
value_topo_info<valtype>::add_val (ipcp_value<valtype> *cur_val)
{
  ipcp_value_source<valtype> *src;

  if (cur_val->dfs)
    return;

  dfs_counter++;
  cur_val->dfs = dfs_counter;
  cur_val->low_link = dfs_counter;

  cur_val->topo_next = stack;
  stack = cur_val;
  cur_val->on_stack = true;

  for (src = cur_val->sources; src; src = src->next)
    if (src->val)
      {
	if (src->val->dfs == 0)
	  {
	    add_val (src->val);
	    if (src->val->low_link < cur_val->low_link)
	      cur_val->low_link = src->val->low_link;
	  }
	else if (src->val->on_stack
		 && src->val->dfs < cur_val->low_link)
	  cur_val->low_link = src->val->dfs;
      }

  if (cur_val->dfs == cur_val->low_link)
    {
      ipcp_value<valtype> *v, *scc_list = NULL;

      do
	{
	  v = stack;
	  stack = v->topo_next;
	  v->on_stack = false;

	  v->scc_next = scc_list;
	  scc_list = v;
	}
      while (v != cur_val);

      cur_val->topo_next = values_topo;
      values_topo = cur_val;
    }
}

/* Add all values in lattices associated with NODE to the topological sort if
   they are not there yet.  */

static void
add_all_node_vals_to_toposort (cgraph_node *node, ipa_topo_info *topo)
{
  struct ipa_node_params *info = IPA_NODE_REF (node);
  int i, count = ipa_get_param_count (info);

  for (i = 0; i < count ; i++)
    {
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (info, i);
      ipcp_lattice<tree> *lat = &plats->itself;
      struct ipcp_agg_lattice *aglat;

      if (!lat->bottom)
	{
	  ipcp_value<tree> *val;
	  for (val = lat->values; val; val = val->next)
	    topo->constants.add_val (val);
	}

      if (!plats->aggs_bottom)
	for (aglat = plats->aggs; aglat; aglat = aglat->next)
	  if (!aglat->bottom)
	    {
	      ipcp_value<tree> *val;
	      for (val = aglat->values; val; val = val->next)
		topo->constants.add_val (val);
	    }

      ipcp_lattice<ipa_polymorphic_call_context> *ctxlat = &plats->ctxlat;
      if (!ctxlat->bottom)
	{
	  ipcp_value<ipa_polymorphic_call_context> *ctxval;
	  for (ctxval = ctxlat->values; ctxval; ctxval = ctxval->next)
	    topo->contexts.add_val (ctxval);
	}
    }
}

/* One pass of constants propagation along the call graph edges, from callers
   to callees (requires topological ordering in TOPO), iterate over strongly
   connected components.  */

static void
propagate_constants_topo (struct ipa_topo_info *topo)
{
  int i;

  for (i = topo->nnodes - 1; i >= 0; i--)
    {
      unsigned j;
      struct cgraph_node *v, *node = topo->order[i];
      vec<cgraph_node *> cycle_nodes = ipa_get_nodes_in_cycle (node);

      /* First, iteratively propagate within the strongly connected component
	 until all lattices stabilize.  */
      FOR_EACH_VEC_ELT (cycle_nodes, j, v)
	if (v->has_gimple_body_p ())
	  push_node_to_stack (topo, v);

      v = pop_node_from_stack (topo);
      while (v)
	{
	  struct cgraph_edge *cs;

	  for (cs = v->callees; cs; cs = cs->next_callee)
	    if (ipa_edge_within_scc (cs))
	      {
		IPA_NODE_REF (v)->node_within_scc = true;
		if (propagate_constants_accross_call (cs))
		  push_node_to_stack (topo, cs->callee->function_symbol ());
	      }
	  v = pop_node_from_stack (topo);
	}

      /* Afterwards, propagate along edges leading out of the SCC, calculates
	 the local effects of the discovered constants and all valid values to
	 their topological sort.  */
      FOR_EACH_VEC_ELT (cycle_nodes, j, v)
	if (v->has_gimple_body_p ())
	  {
	    struct cgraph_edge *cs;

	    estimate_local_effects (v);
	    add_all_node_vals_to_toposort (v, topo);
	    for (cs = v->callees; cs; cs = cs->next_callee)
	      if (!ipa_edge_within_scc (cs))
		propagate_constants_accross_call (cs);
	  }
      cycle_nodes.release ();
    }
}


/* Return the sum of A and B if none of them is bigger than INT_MAX/2, return
   the bigger one if otherwise.  */

static int
safe_add (int a, int b)
{
  if (a > INT_MAX/2 || b > INT_MAX/2)
    return a > b ? a : b;
  else
    return a + b;
}


/* Propagate the estimated effects of individual values along the topological
   from the dependent values to those they depend on.  */

template <typename valtype>
void
value_topo_info<valtype>::propagate_effects ()
{
  ipcp_value<valtype> *base;

  for (base = values_topo; base; base = base->topo_next)
    {
      ipcp_value_source<valtype> *src;
      ipcp_value<valtype> *val;
      int time = 0, size = 0;

      for (val = base; val; val = val->scc_next)
	{
	  time = safe_add (time,
			   val->local_time_benefit + val->prop_time_benefit);
	  size = safe_add (size, val->local_size_cost + val->prop_size_cost);
	}

      for (val = base; val; val = val->scc_next)
	for (src = val->sources; src; src = src->next)
	  if (src->val
	      && src->cs->maybe_hot_p ())
	    {
	      src->val->prop_time_benefit = safe_add (time,
						src->val->prop_time_benefit);
	      src->val->prop_size_cost = safe_add (size,
						   src->val->prop_size_cost);
	    }
    }
}


/* Propagate constants, polymorphic contexts and their effects from the
   summaries interprocedurally.  */

static void
ipcp_propagate_stage (struct ipa_topo_info *topo)
{
  struct cgraph_node *node;

  if (dump_file)
    fprintf (dump_file, "\n Propagating constants:\n\n");

  if (in_lto_p)
    ipa_update_after_lto_read ();


  FOR_EACH_DEFINED_FUNCTION (node)
  {
    struct ipa_node_params *info = IPA_NODE_REF (node);

    determine_versionability (node);
    if (node->has_gimple_body_p ())
      {
	info->lattices = XCNEWVEC (struct ipcp_param_lattices,
				   ipa_get_param_count (info));
	initialize_node_lattices (node);
      }
    if (node->definition && !node->alias)
      overall_size += inline_summaries->get (node)->self_size;
    if (node->count > max_count)
      max_count = node->count;
  }

  max_new_size = overall_size;
  if (max_new_size < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
    max_new_size = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
  max_new_size += max_new_size * PARAM_VALUE (PARAM_IPCP_UNIT_GROWTH) / 100 + 1;

  if (dump_file)
    fprintf (dump_file, "\noverall_size: %li, max_new_size: %li\n",
	     overall_size, max_new_size);

  propagate_constants_topo (topo);
#ifdef ENABLE_CHECKING
  ipcp_verify_propagated_values ();
#endif
  topo->constants.propagate_effects ();
  topo->contexts.propagate_effects ();

  if (dump_file)
    {
      fprintf (dump_file, "\nIPA lattices after all propagation:\n");
      print_all_lattices (dump_file, (dump_flags & TDF_DETAILS), true);
    }
}

/* Discover newly direct outgoing edges from NODE which is a new clone with
   known KNOWN_CSTS and make them direct.  */

static void
ipcp_discover_new_direct_edges (struct cgraph_node *node,
				vec<tree> known_csts,
				vec<ipa_polymorphic_call_context>
				known_contexts,
				struct ipa_agg_replacement_value *aggvals)
{
  struct cgraph_edge *ie, *next_ie;
  bool found = false;

  for (ie = node->indirect_calls; ie; ie = next_ie)
    {
      tree target;
      bool speculative;

      next_ie = ie->next_callee;
      target = ipa_get_indirect_edge_target_1 (ie, known_csts, known_contexts,
					       vNULL, aggvals, &speculative);
      if (target)
	{
	  bool agg_contents = ie->indirect_info->agg_contents;
	  bool polymorphic = ie->indirect_info->polymorphic;
	  int param_index = ie->indirect_info->param_index;
	  struct cgraph_edge *cs = ipa_make_edge_direct_to_target (ie, target,
								   speculative);
	  found = true;

	  if (cs && !agg_contents && !polymorphic)
	    {
	      struct ipa_node_params *info = IPA_NODE_REF (node);
	      int c = ipa_get_controlled_uses (info, param_index);
	      if (c != IPA_UNDESCRIBED_USE)
		{
		  struct ipa_ref *to_del;

		  c--;
		  ipa_set_controlled_uses (info, param_index, c);
		  if (dump_file && (dump_flags & TDF_DETAILS))
		    fprintf (dump_file, "     controlled uses count of param "
			     "%i bumped down to %i\n", param_index, c);
		  if (c == 0
		      && (to_del = node->find_reference (cs->callee, NULL, 0)))
		    {
		      if (dump_file && (dump_flags & TDF_DETAILS))
			fprintf (dump_file, "       and even removing its "
				 "cloning-created reference\n");
		      to_del->remove_reference ();
		    }
		}
	    }
	}
    }
  /* Turning calls to direct calls will improve overall summary.  */
  if (found)
    inline_update_overall_summary (node);
}

/* Vector of pointers which for linked lists of clones of an original crgaph
   edge. */

static vec<cgraph_edge *> next_edge_clone;
static vec<cgraph_edge *> prev_edge_clone;

static inline void
grow_edge_clone_vectors (void)
{
  if (next_edge_clone.length ()
      <=  (unsigned) symtab->edges_max_uid)
    next_edge_clone.safe_grow_cleared (symtab->edges_max_uid + 1);
  if (prev_edge_clone.length ()
      <=  (unsigned) symtab->edges_max_uid)
    prev_edge_clone.safe_grow_cleared (symtab->edges_max_uid + 1);
}

/* Edge duplication hook to grow the appropriate linked list in
   next_edge_clone. */

static void
ipcp_edge_duplication_hook (struct cgraph_edge *src, struct cgraph_edge *dst,
			    void *)
{
  grow_edge_clone_vectors ();

  struct cgraph_edge *old_next = next_edge_clone[src->uid];
  if (old_next)
    prev_edge_clone[old_next->uid] = dst;
  prev_edge_clone[dst->uid] = src;

  next_edge_clone[dst->uid] = old_next;
  next_edge_clone[src->uid] = dst;
}

/* Hook that is called by cgraph.c when an edge is removed.  */

static void
ipcp_edge_removal_hook (struct cgraph_edge *cs, void *)
{
  grow_edge_clone_vectors ();

  struct cgraph_edge *prev = prev_edge_clone[cs->uid];
  struct cgraph_edge *next = next_edge_clone[cs->uid];
  if (prev)
    next_edge_clone[prev->uid] = next;
  if (next)
    prev_edge_clone[next->uid] = prev;
}

/* See if NODE is a clone with a known aggregate value at a given OFFSET of a
   parameter with the given INDEX.  */

static tree
get_clone_agg_value (struct cgraph_node *node, HOST_WIDE_INT offset,
		     int index)
{
  struct ipa_agg_replacement_value *aggval;

  aggval = ipa_get_agg_replacements_for_node (node);
  while (aggval)
    {
      if (aggval->offset == offset
	  && aggval->index == index)
	return aggval->value;
      aggval = aggval->next;
    }
  return NULL_TREE;
}

/* Return true is NODE is DEST or its clone for all contexts.  */

static bool
same_node_or_its_all_contexts_clone_p (cgraph_node *node, cgraph_node *dest)
{
  if (node == dest)
    return true;

  struct ipa_node_params *info = IPA_NODE_REF (node);
  return info->is_all_contexts_clone && info->ipcp_orig_node == dest;
}

/* Return true if edge CS does bring about the value described by SRC to node
   DEST or its clone for all contexts.  */

static bool
cgraph_edge_brings_value_p (cgraph_edge *cs, ipcp_value_source<tree> *src,
			    cgraph_node *dest)
{
  struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
  enum availability availability;
  cgraph_node *real_dest = cs->callee->function_symbol (&availability);

  if (!same_node_or_its_all_contexts_clone_p (real_dest, dest)
      || availability <= AVAIL_INTERPOSABLE
      || caller_info->node_dead)
    return false;
  if (!src->val)
    return true;

  if (caller_info->ipcp_orig_node)
    {
      tree t;
      if (src->offset == -1)
	t = caller_info->known_csts[src->index];
      else
	t = get_clone_agg_value (cs->caller, src->offset, src->index);
      return (t != NULL_TREE
	      && values_equal_for_ipcp_p (src->val->value, t));
    }
  else
    {
      struct ipcp_agg_lattice *aglat;
      struct ipcp_param_lattices *plats = ipa_get_parm_lattices (caller_info,
								 src->index);
      if (src->offset == -1)
	return (plats->itself.is_single_const ()
		&& values_equal_for_ipcp_p (src->val->value,
					    plats->itself.values->value));
      else
	{
	  if (plats->aggs_bottom || plats->aggs_contain_variable)
	    return false;
	  for (aglat = plats->aggs; aglat; aglat = aglat->next)
	    if (aglat->offset == src->offset)
	      return  (aglat->is_single_const ()
		       && values_equal_for_ipcp_p (src->val->value,
						   aglat->values->value));
	}
      return false;
    }
}

/* Return true if edge CS does bring about the value described by SRC to node
   DEST or its clone for all contexts.  */

static bool
cgraph_edge_brings_value_p (cgraph_edge *cs,
			    ipcp_value_source<ipa_polymorphic_call_context> *src,
			    cgraph_node *dest)
{
  struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
  cgraph_node *real_dest = cs->callee->function_symbol ();

  if (!same_node_or_its_all_contexts_clone_p (real_dest, dest)
      || caller_info->node_dead)
    return false;
  if (!src->val)
    return true;

  if (caller_info->ipcp_orig_node)
    return (caller_info->known_contexts.length () > (unsigned) src->index)
      && values_equal_for_ipcp_p (src->val->value,
				  caller_info->known_contexts[src->index]);

  struct ipcp_param_lattices *plats = ipa_get_parm_lattices (caller_info,
							     src->index);
  return plats->ctxlat.is_single_const ()
    && values_equal_for_ipcp_p (src->val->value,
				plats->ctxlat.values->value);
}

/* Get the next clone in the linked list of clones of an edge.  */

static inline struct cgraph_edge *
get_next_cgraph_edge_clone (struct cgraph_edge *cs)
{
  return next_edge_clone[cs->uid];
}

/* Given VAL that is intended for DEST, iterate over all its sources and if
   they still hold, add their edge frequency and their number into *FREQUENCY
   and *CALLER_COUNT respectively.  */

template <typename valtype>
static bool
get_info_about_necessary_edges (ipcp_value<valtype> *val, cgraph_node *dest,
				int *freq_sum,
				gcov_type *count_sum, int *caller_count)
{
  ipcp_value_source<valtype> *src;
  int freq = 0, count = 0;
  gcov_type cnt = 0;
  bool hot = false;

  for (src = val->sources; src; src = src->next)
    {
      struct cgraph_edge *cs = src->cs;
      while (cs)
	{
	  if (cgraph_edge_brings_value_p (cs, src, dest))
	    {
	      count++;
	      freq += cs->frequency;
	      cnt += cs->count;
	      hot |= cs->maybe_hot_p ();
	    }
	  cs = get_next_cgraph_edge_clone (cs);
	}
    }

  *freq_sum = freq;
  *count_sum = cnt;
  *caller_count = count;
  return hot;
}

/* Return a vector of incoming edges that do bring value VAL to node DEST.  It
   is assumed their number is known and equal to CALLER_COUNT.  */

template <typename valtype>
static vec<cgraph_edge *>
gather_edges_for_value (ipcp_value<valtype> *val, cgraph_node *dest,
			int caller_count)
{
  ipcp_value_source<valtype> *src;
  vec<cgraph_edge *> ret;

  ret.create (caller_count);
  for (src = val->sources; src; src = src->next)
    {
      struct cgraph_edge *cs = src->cs;
      while (cs)
	{
	  if (cgraph_edge_brings_value_p (cs, src, dest))
	    ret.quick_push (cs);
	  cs = get_next_cgraph_edge_clone (cs);
	}
    }

  return ret;
}

/* Construct a replacement map for a know VALUE for a formal parameter PARAM.
   Return it or NULL if for some reason it cannot be created.  */

static struct ipa_replace_map *
get_replacement_map (struct ipa_node_params *info, tree value, int parm_num)
{
  struct ipa_replace_map *replace_map;


  replace_map = ggc_alloc<ipa_replace_map> ();
  if (dump_file)
    {
      fprintf (dump_file, "    replacing ");