* omp-low.c (optimize_omp_library_calls): Use types_compatible_p

[pf3gnuchains/gcc-fork.git] / gcc / omp-low.c

/* Lowering pass for OpenMP directives.  Converts OpenMP directives
   into explicit calls to the runtime library (libgomp) and data
   marshalling to implement data sharing and copying clauses.
   Contributed by Diego Novillo <dnovillo@redhat.com>

   Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "gimple.h"
#include "tree-iterator.h"
#include "tree-inline.h"
#include "langhooks.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "timevar.h"
#include "flags.h"
#include "function.h"
#include "expr.h"
#include "toplev.h"
#include "tree-pass.h"
#include "ggc.h"
#include "except.h"
#include "splay-tree.h"
#include "optabs.h"
#include "cfgloop.h"


/* Lowering of OpenMP parallel and workshare constructs proceeds in two 
   phases.  The first phase scans the function looking for OMP statements
   and then for variables that must be replaced to satisfy data sharing
   clauses.  The second phase expands code for the constructs, as well as
   re-gimplifying things when variables have been replaced with complex
   expressions.

   Final code generation is done by pass_expand_omp.  The flowgraph is
   scanned for parallel regions which are then moved to a new
   function, to be invoked by the thread library.  */

/* Context structure.  Used to store information about each parallel
   directive in the code.  */

typedef struct omp_context
{
  /* This field must be at the beginning, as we do "inheritance": Some
     callback functions for tree-inline.c (e.g., omp_copy_decl)
     receive a copy_body_data pointer that is up-casted to an
     omp_context pointer.  */
  copy_body_data cb;

  /* The tree of contexts corresponding to the encountered constructs.  */
  struct omp_context *outer;
  gimple stmt;

  /* Map variables to fields in a structure that allows communication 
     between sending and receiving threads.  */
  splay_tree field_map;
  tree record_type;
  tree sender_decl;
  tree receiver_decl;

  /* These are used just by task contexts, if task firstprivate fn is
     needed.  srecord_type is used to communicate from the thread
     that encountered the task construct to task firstprivate fn,
     record_type is allocated by GOMP_task, initialized by task firstprivate
     fn and passed to the task body fn.  */
  splay_tree sfield_map;
  tree srecord_type;

  /* A chain of variables to add to the top-level block surrounding the
     construct.  In the case of a parallel, this is in the child function.  */
  tree block_vars;

  /* What to do with variables with implicitly determined sharing
     attributes.  */
  enum omp_clause_default_kind default_kind;

  /* Nesting depth of this context.  Used to beautify error messages re
     invalid gotos.  The outermost ctx is depth 1, with depth 0 being
     reserved for the main body of the function.  */
  int depth;

  /* True if this parallel directive is nested within another.  */
  bool is_nested;
} omp_context;


struct omp_for_data_loop
{
  tree v, n1, n2, step;
  enum tree_code cond_code;
};

/* A structure describing the main elements of a parallel loop.  */

struct omp_for_data
{
  struct omp_for_data_loop loop;
  tree chunk_size;
  gimple for_stmt;
  tree pre, iter_type;
  int collapse;
  bool have_nowait, have_ordered;
  enum omp_clause_schedule_kind sched_kind;
  struct omp_for_data_loop *loops;
};


static splay_tree all_contexts;
static int taskreg_nesting_level;
struct omp_region *root_omp_region;
static bitmap task_shared_vars;

static void scan_omp (gimple_seq, omp_context *);
static tree scan_omp_1_op (tree *, int *, void *);

#define WALK_SUBSTMTS  \
    case GIMPLE_BIND: \
    case GIMPLE_TRY: \
    case GIMPLE_CATCH: \
    case GIMPLE_EH_FILTER: \
      /* The sub-statements for these should be walked.  */ \
      *handled_ops_p = false; \
      break;

/* Convenience function for calling scan_omp_1_op on tree operands.  */

static inline tree
scan_omp_op (tree *tp, omp_context *ctx)
{
  struct walk_stmt_info wi;

  memset (&wi, 0, sizeof (wi));
  wi.info = ctx;
  wi.want_locations = true;

  return walk_tree (tp, scan_omp_1_op, &wi, NULL);
}

static void lower_omp (gimple_seq, omp_context *);
static tree lookup_decl_in_outer_ctx (tree, omp_context *);
static tree maybe_lookup_decl_in_outer_ctx (tree, omp_context *);

/* Find an OpenMP clause of type KIND within CLAUSES.  */

tree
find_omp_clause (tree clauses, enum omp_clause_code kind)
{
  for (; clauses ; clauses = OMP_CLAUSE_CHAIN (clauses))
    if (OMP_CLAUSE_CODE (clauses) == kind)
      return clauses;

  return NULL_TREE;
}

/* Return true if CTX is for an omp parallel.  */

static inline bool
is_parallel_ctx (omp_context *ctx)
{
  return gimple_code (ctx->stmt) == GIMPLE_OMP_PARALLEL;
}


/* Return true if CTX is for an omp task.  */

static inline bool
is_task_ctx (omp_context *ctx)
{
  return gimple_code (ctx->stmt) == GIMPLE_OMP_TASK;
}


/* Return true if CTX is for an omp parallel or omp task.  */

static inline bool
is_taskreg_ctx (omp_context *ctx)
{
  return gimple_code (ctx->stmt) == GIMPLE_OMP_PARALLEL
         || gimple_code (ctx->stmt) == GIMPLE_OMP_TASK;
}


/* Return true if REGION is a combined parallel+workshare region.  */

static inline bool
is_combined_parallel (struct omp_region *region)
{
  return region->is_combined_parallel;
}


/* Extract the header elements of parallel loop FOR_STMT and store
   them into *FD.  */

static void
extract_omp_for_data (gimple for_stmt, struct omp_for_data *fd,
                      struct omp_for_data_loop *loops)
{
  tree t, var, *collapse_iter, *collapse_count;
  tree count = NULL_TREE, iter_type = long_integer_type_node;
  struct omp_for_data_loop *loop;
  int i;
  struct omp_for_data_loop dummy_loop;
  location_t loc = gimple_location (for_stmt);

  fd->for_stmt = for_stmt;
  fd->pre = NULL;
  fd->collapse = gimple_omp_for_collapse (for_stmt);
  if (fd->collapse > 1)
    fd->loops = loops;
  else
    fd->loops = &fd->loop;

  fd->have_nowait = fd->have_ordered = false;
  fd->sched_kind = OMP_CLAUSE_SCHEDULE_STATIC;
  fd->chunk_size = NULL_TREE;
  collapse_iter = NULL;
  collapse_count = NULL;

  for (t = gimple_omp_for_clauses (for_stmt); t ; t = OMP_CLAUSE_CHAIN (t))
    switch (OMP_CLAUSE_CODE (t))
      {
      case OMP_CLAUSE_NOWAIT:
        fd->have_nowait = true;
        break;
      case OMP_CLAUSE_ORDERED:
        fd->have_ordered = true;
        break;
      case OMP_CLAUSE_SCHEDULE:
        fd->sched_kind = OMP_CLAUSE_SCHEDULE_KIND (t);
        fd->chunk_size = OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (t);
        break;
      case OMP_CLAUSE_COLLAPSE:
        if (fd->collapse > 1)
          {
            collapse_iter = &OMP_CLAUSE_COLLAPSE_ITERVAR (t);
            collapse_count = &OMP_CLAUSE_COLLAPSE_COUNT (t);
          }
      default:
        break;
      }

  /* FIXME: for now map schedule(auto) to schedule(static).
     There should be analysis to determine whether all iterations
     are approximately the same amount of work (then schedule(static)
     is best) or if it varies (then schedule(dynamic,N) is better).  */
  if (fd->sched_kind == OMP_CLAUSE_SCHEDULE_AUTO)
    {
      fd->sched_kind = OMP_CLAUSE_SCHEDULE_STATIC;
      gcc_assert (fd->chunk_size == NULL);
    }
  gcc_assert (fd->collapse == 1 || collapse_iter != NULL);
  if (fd->sched_kind == OMP_CLAUSE_SCHEDULE_RUNTIME)
    gcc_assert (fd->chunk_size == NULL);
  else if (fd->chunk_size == NULL)
    {
      /* We only need to compute a default chunk size for ordered
         static loops and dynamic loops.  */
      if (fd->sched_kind != OMP_CLAUSE_SCHEDULE_STATIC
          || fd->have_ordered
          || fd->collapse > 1)
        fd->chunk_size = (fd->sched_kind == OMP_CLAUSE_SCHEDULE_STATIC)
                         ? integer_zero_node : integer_one_node;
    }

  for (i = 0; i < fd->collapse; i++)
    {
      if (fd->collapse == 1)
        loop = &fd->loop;
      else if (loops != NULL)
        loop = loops + i;
      else
        loop = &dummy_loop;

      
      loop->v = gimple_omp_for_index (for_stmt, i);
      gcc_assert (SSA_VAR_P (loop->v));
      gcc_assert (TREE_CODE (TREE_TYPE (loop->v)) == INTEGER_TYPE
                  || TREE_CODE (TREE_TYPE (loop->v)) == POINTER_TYPE);
      var = TREE_CODE (loop->v) == SSA_NAME ? SSA_NAME_VAR (loop->v) : loop->v;
      loop->n1 = gimple_omp_for_initial (for_stmt, i);

      loop->cond_code = gimple_omp_for_cond (for_stmt, i);
      loop->n2 = gimple_omp_for_final (for_stmt, i);
      switch (loop->cond_code)
        {
        case LT_EXPR:
        case GT_EXPR:
          break;
        case LE_EXPR:
          if (POINTER_TYPE_P (TREE_TYPE (loop->n2)))
            loop->n2 = fold_build2_loc (loc,
                                    POINTER_PLUS_EXPR, TREE_TYPE (loop->n2),
                                    loop->n2, size_one_node);
          else
            loop->n2 = fold_build2_loc (loc,
                                    PLUS_EXPR, TREE_TYPE (loop->n2), loop->n2,
                                    build_int_cst (TREE_TYPE (loop->n2), 1));
          loop->cond_code = LT_EXPR;
          break;
        case GE_EXPR:
          if (POINTER_TYPE_P (TREE_TYPE (loop->n2)))
            loop->n2 = fold_build2_loc (loc,
                                    POINTER_PLUS_EXPR, TREE_TYPE (loop->n2),
                                    loop->n2, size_int (-1));
          else
            loop->n2 = fold_build2_loc (loc,
                                    MINUS_EXPR, TREE_TYPE (loop->n2), loop->n2,
                                    build_int_cst (TREE_TYPE (loop->n2), 1));
          loop->cond_code = GT_EXPR;
          break;
        default:
          gcc_unreachable ();
        }

      t = gimple_omp_for_incr (for_stmt, i);
      gcc_assert (TREE_OPERAND (t, 0) == var);
      switch (TREE_CODE (t))
        {
        case PLUS_EXPR:
        case POINTER_PLUS_EXPR:
          loop->step = TREE_OPERAND (t, 1);
          break;
        case MINUS_EXPR:
          loop->step = TREE_OPERAND (t, 1);
          loop->step = fold_build1_loc (loc,
                                    NEGATE_EXPR, TREE_TYPE (loop->step),
                                    loop->step);
          break;
        default:
          gcc_unreachable ();
        }

      if (iter_type != long_long_unsigned_type_node)
        {
          if (POINTER_TYPE_P (TREE_TYPE (loop->v)))
            iter_type = long_long_unsigned_type_node;
          else if (TYPE_UNSIGNED (TREE_TYPE (loop->v))
                   && TYPE_PRECISION (TREE_TYPE (loop->v))
                      >= TYPE_PRECISION (iter_type))
            {
              tree n;

              if (loop->cond_code == LT_EXPR)
                n = fold_build2_loc (loc,
                                 PLUS_EXPR, TREE_TYPE (loop->v),
                                 loop->n2, loop->step);
              else
                n = loop->n1;
              if (TREE_CODE (n) != INTEGER_CST
                  || tree_int_cst_lt (TYPE_MAX_VALUE (iter_type), n))
                iter_type = long_long_unsigned_type_node;
            }
          else if (TYPE_PRECISION (TREE_TYPE (loop->v))
                   > TYPE_PRECISION (iter_type))
            {
              tree n1, n2;

              if (loop->cond_code == LT_EXPR)
                {
                  n1 = loop->n1;
                  n2 = fold_build2_loc (loc,
                                    PLUS_EXPR, TREE_TYPE (loop->v),
                                    loop->n2, loop->step);
                }
              else
                {
                  n1 = fold_build2_loc (loc,
                                    MINUS_EXPR, TREE_TYPE (loop->v),
                                    loop->n2, loop->step);
                  n2 = loop->n1;
                }
              if (TREE_CODE (n1) != INTEGER_CST
                  || TREE_CODE (n2) != INTEGER_CST
                  || !tree_int_cst_lt (TYPE_MIN_VALUE (iter_type), n1)
                  || !tree_int_cst_lt (n2, TYPE_MAX_VALUE (iter_type)))
                iter_type = long_long_unsigned_type_node;
            }
        }

      if (collapse_count && *collapse_count == NULL)
        {
          if ((i == 0 || count != NULL_TREE)
              && TREE_CODE (TREE_TYPE (loop->v)) == INTEGER_TYPE
              && TREE_CONSTANT (loop->n1)
              && TREE_CONSTANT (loop->n2)
              && TREE_CODE (loop->step) == INTEGER_CST)
            {
              tree itype = TREE_TYPE (loop->v);

              if (POINTER_TYPE_P (itype))
                itype
                  = lang_hooks.types.type_for_size (TYPE_PRECISION (itype), 0);
              t = build_int_cst (itype, (loop->cond_code == LT_EXPR ? -1 : 1));
              t = fold_build2_loc (loc,
                               PLUS_EXPR, itype,
                               fold_convert_loc (loc, itype, loop->step), t);
              t = fold_build2_loc (loc, PLUS_EXPR, itype, t,
                               fold_convert_loc (loc, itype, loop->n2));
              t = fold_build2_loc (loc, MINUS_EXPR, itype, t,
                               fold_convert_loc (loc, itype, loop->n1));
              if (TYPE_UNSIGNED (itype) && loop->cond_code == GT_EXPR)
                t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
                                 fold_build1_loc (loc, NEGATE_EXPR, itype, t),
                                 fold_build1_loc (loc, NEGATE_EXPR, itype,
                                              fold_convert_loc (loc, itype,
                                                                loop->step)));
              else
                t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
                                 fold_convert_loc (loc, itype, loop->step));
              t = fold_convert_loc (loc, long_long_unsigned_type_node, t);
              if (count != NULL_TREE)
                count = fold_build2_loc (loc,
                                     MULT_EXPR, long_long_unsigned_type_node,
                                     count, t);
              else
                count = t;
              if (TREE_CODE (count) != INTEGER_CST)
                count = NULL_TREE;
            }
          else
            count = NULL_TREE;
        }
    }

  if (count)
    {
      if (!tree_int_cst_lt (count, TYPE_MAX_VALUE (long_integer_type_node)))
        iter_type = long_long_unsigned_type_node;
      else
        iter_type = long_integer_type_node;
    }
  else if (collapse_iter && *collapse_iter != NULL)
    iter_type = TREE_TYPE (*collapse_iter);
  fd->iter_type = iter_type;
  if (collapse_iter && *collapse_iter == NULL)
    *collapse_iter = create_tmp_var (iter_type, ".iter");
  if (collapse_count && *collapse_count == NULL)
    {
      if (count)
        *collapse_count = fold_convert_loc (loc, iter_type, count);
      else
        *collapse_count = create_tmp_var (iter_type, ".count");
    }

  if (fd->collapse > 1)
    {
      fd->loop.v = *collapse_iter;
      fd->loop.n1 = build_int_cst (TREE_TYPE (fd->loop.v), 0);
      fd->loop.n2 = *collapse_count;
      fd->loop.step = build_int_cst (TREE_TYPE (fd->loop.v), 1);
      fd->loop.cond_code = LT_EXPR;
    }
}


/* Given two blocks PAR_ENTRY_BB and WS_ENTRY_BB such that WS_ENTRY_BB
   is the immediate dominator of PAR_ENTRY_BB, return true if there
   are no data dependencies that would prevent expanding the parallel
   directive at PAR_ENTRY_BB as a combined parallel+workshare region.

   When expanding a combined parallel+workshare region, the call to
   the child function may need additional arguments in the case of
   GIMPLE_OMP_FOR regions.  In some cases, these arguments are
   computed out of variables passed in from the parent to the child
   via 'struct .omp_data_s'.  For instance:

        #pragma omp parallel for schedule (guided, i * 4)
        for (j ...)

   Is lowered into:

        # BLOCK 2 (PAR_ENTRY_BB)
        .omp_data_o.i = i;
        #pragma omp parallel [child fn: bar.omp_fn.0 ( ..., D.1598)
        
        # BLOCK 3 (WS_ENTRY_BB)
        .omp_data_i = &.omp_data_o;
        D.1667 = .omp_data_i->i;
        D.1598 = D.1667 * 4;
        #pragma omp for schedule (guided, D.1598)

   When we outline the parallel region, the call to the child function
   'bar.omp_fn.0' will need the value D.1598 in its argument list, but
   that value is computed *after* the call site.  So, in principle we
   cannot do the transformation.

   To see whether the code in WS_ENTRY_BB blocks the combined
   parallel+workshare call, we collect all the variables used in the
   GIMPLE_OMP_FOR header check whether they appear on the LHS of any
   statement in WS_ENTRY_BB.  If so, then we cannot emit the combined
   call.

   FIXME.  If we had the SSA form built at this point, we could merely
   hoist the code in block 3 into block 2 and be done with it.  But at
   this point we don't have dataflow information and though we could
   hack something up here, it is really not worth the aggravation.  */

static bool
workshare_safe_to_combine_p (basic_block par_entry_bb, basic_block ws_entry_bb)
{
  struct omp_for_data fd;
  gimple par_stmt, ws_stmt;

  par_stmt = last_stmt (par_entry_bb);
  ws_stmt = last_stmt (ws_entry_bb);

  if (gimple_code (ws_stmt) == GIMPLE_OMP_SECTIONS)
    return true;

  gcc_assert (gimple_code (ws_stmt) == GIMPLE_OMP_FOR);

  extract_omp_for_data (ws_stmt, &fd, NULL);

  if (fd.collapse > 1 && TREE_CODE (fd.loop.n2) != INTEGER_CST)
    return false;
  if (fd.iter_type != long_integer_type_node)
    return false;

  /* FIXME.  We give up too easily here.  If any of these arguments
     are not constants, they will likely involve variables that have
     been mapped into fields of .omp_data_s for sharing with the child
     function.  With appropriate data flow, it would be possible to
     see through this.  */
  if (!is_gimple_min_invariant (fd.loop.n1)
      || !is_gimple_min_invariant (fd.loop.n2)
      || !is_gimple_min_invariant (fd.loop.step)
      || (fd.chunk_size && !is_gimple_min_invariant (fd.chunk_size)))
    return false;

  return true;
}


/* Collect additional arguments needed to emit a combined
   parallel+workshare call.  WS_STMT is the workshare directive being
   expanded.  */

static tree
get_ws_args_for (gimple ws_stmt)
{
  tree t;
  location_t loc = gimple_location (ws_stmt);

  if (gimple_code (ws_stmt) == GIMPLE_OMP_FOR)
    {
      struct omp_for_data fd;
      tree ws_args;

      extract_omp_for_data (ws_stmt, &fd, NULL);

      ws_args = NULL_TREE;
      if (fd.chunk_size)
        {
          t = fold_convert_loc (loc, long_integer_type_node, fd.chunk_size);
          ws_args = tree_cons (NULL, t, ws_args);
        }

      t = fold_convert_loc (loc, long_integer_type_node, fd.loop.step);
      ws_args = tree_cons (NULL, t, ws_args);

      t = fold_convert_loc (loc, long_integer_type_node, fd.loop.n2);
      ws_args = tree_cons (NULL, t, ws_args);

      t = fold_convert_loc (loc, long_integer_type_node, fd.loop.n1);
      ws_args = tree_cons (NULL, t, ws_args);

      return ws_args;
    }
  else if (gimple_code (ws_stmt) == GIMPLE_OMP_SECTIONS)
    {
      /* Number of sections is equal to the number of edges from the
         GIMPLE_OMP_SECTIONS_SWITCH statement, except for the one to
         the exit of the sections region.  */
      basic_block bb = single_succ (gimple_bb (ws_stmt));
      t = build_int_cst (unsigned_type_node, EDGE_COUNT (bb->succs) - 1);
      t = tree_cons (NULL, t, NULL);
      return t;
    }

  gcc_unreachable ();
}


/* Discover whether REGION is a combined parallel+workshare region.  */

static void
determine_parallel_type (struct omp_region *region)
{
  basic_block par_entry_bb, par_exit_bb;
  basic_block ws_entry_bb, ws_exit_bb;

  if (region == NULL || region->inner == NULL
      || region->exit == NULL || region->inner->exit == NULL
      || region->inner->cont == NULL)
    return;

  /* We only support parallel+for and parallel+sections.  */
  if (region->type != GIMPLE_OMP_PARALLEL
      || (region->inner->type != GIMPLE_OMP_FOR
          && region->inner->type != GIMPLE_OMP_SECTIONS))
    return;

  /* Check for perfect nesting PAR_ENTRY_BB -> WS_ENTRY_BB and
     WS_EXIT_BB -> PAR_EXIT_BB.  */
  par_entry_bb = region->entry;
  par_exit_bb = region->exit;
  ws_entry_bb = region->inner->entry;
  ws_exit_bb = region->inner->exit;

  if (single_succ (par_entry_bb) == ws_entry_bb
      && single_succ (ws_exit_bb) == par_exit_bb
      && workshare_safe_to_combine_p (par_entry_bb, ws_entry_bb)
      && (gimple_omp_parallel_combined_p (last_stmt (par_entry_bb))
          || (last_and_only_stmt (ws_entry_bb)
              && last_and_only_stmt (par_exit_bb))))
    {
      gimple ws_stmt = last_stmt (ws_entry_bb);

      if (region->inner->type == GIMPLE_OMP_FOR)
        {
          /* If this is a combined parallel loop, we need to determine
             whether or not to use the combined library calls.  There
             are two cases where we do not apply the transformation:
             static loops and any kind of ordered loop.  In the first
             case, we already open code the loop so there is no need
             to do anything else.  In the latter case, the combined
             parallel loop call would still need extra synchronization
             to implement ordered semantics, so there would not be any
             gain in using the combined call.  */
          tree clauses = gimple_omp_for_clauses (ws_stmt);
          tree c = find_omp_clause (clauses, OMP_CLAUSE_SCHEDULE);
          if (c == NULL
              || OMP_CLAUSE_SCHEDULE_KIND (c) == OMP_CLAUSE_SCHEDULE_STATIC
              || find_omp_clause (clauses, OMP_CLAUSE_ORDERED))
            {
              region->is_combined_parallel = false;
              region->inner->is_combined_parallel = false;
              return;
            }
        }

      region->is_combined_parallel = true;
      region->inner->is_combined_parallel = true;
      region->ws_args = get_ws_args_for (ws_stmt);
    }
}


/* Return true if EXPR is variable sized.  */

static inline bool
is_variable_sized (const_tree expr)
{
  return !TREE_CONSTANT (TYPE_SIZE_UNIT (TREE_TYPE (expr)));
}

/* Return true if DECL is a reference type.  */

static inline bool
is_reference (tree decl)
{
  return lang_hooks.decls.omp_privatize_by_reference (decl);
}

/* Lookup variables in the decl or field splay trees.  The "maybe" form
   allows for the variable form to not have been entered, otherwise we
   assert that the variable must have been entered.  */

static inline tree
lookup_decl (tree var, omp_context *ctx)
{
  tree *n;
  n = (tree *) pointer_map_contains (ctx->cb.decl_map, var);
  return *n;
}

static inline tree
maybe_lookup_decl (const_tree var, omp_context *ctx)
{
  tree *n;
  n = (tree *) pointer_map_contains (ctx->cb.decl_map, var);
  return n ? *n : NULL_TREE;
}

static inline tree
lookup_field (tree var, omp_context *ctx)
{
  splay_tree_node n;
  n = splay_tree_lookup (ctx->field_map, (splay_tree_key) var);
  return (tree) n->value;
}

static inline tree
lookup_sfield (tree var, omp_context *ctx)
{
  splay_tree_node n;
  n = splay_tree_lookup (ctx->sfield_map
                         ? ctx->sfield_map : ctx->field_map,
                         (splay_tree_key) var);
  return (tree) n->value;
}

static inline tree
maybe_lookup_field (tree var, omp_context *ctx)
{
  splay_tree_node n;
  n = splay_tree_lookup (ctx->field_map, (splay_tree_key) var);
  return n ? (tree) n->value : NULL_TREE;
}

/* Return true if DECL should be copied by pointer.  SHARED_CTX is
   the parallel context if DECL is to be shared.  */

static bool
use_pointer_for_field (tree decl, omp_context *shared_ctx)
{
  if (AGGREGATE_TYPE_P (TREE_TYPE (decl)))
    return true;

  /* We can only use copy-in/copy-out semantics for shared variables
     when we know the value is not accessible from an outer scope.  */
  if (shared_ctx)
    {
      /* ??? Trivially accessible from anywhere.  But why would we even
         be passing an address in this case?  Should we simply assert
         this to be false, or should we have a cleanup pass that removes
         these from the list of mappings?  */
      if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
        return true;

      /* For variables with DECL_HAS_VALUE_EXPR_P set, we cannot tell
         without analyzing the expression whether or not its location
         is accessible to anyone else.  In the case of nested parallel
         regions it certainly may be.  */
      if (TREE_CODE (decl) != RESULT_DECL && DECL_HAS_VALUE_EXPR_P (decl))
        return true;

      /* Do not use copy-in/copy-out for variables that have their
         address taken.  */
      if (TREE_ADDRESSABLE (decl))
        return true;

      /* Disallow copy-in/out in nested parallel if
         decl is shared in outer parallel, otherwise
         each thread could store the shared variable
         in its own copy-in location, making the
         variable no longer really shared.  */
      if (!TREE_READONLY (decl) && shared_ctx->is_nested)
        {
          omp_context *up;

          for (up = shared_ctx->outer; up; up = up->outer)
            if (is_taskreg_ctx (up) && maybe_lookup_decl (decl, up))
              break;

          if (up)
            {
              tree c;

              for (c = gimple_omp_taskreg_clauses (up->stmt);
                   c; c = OMP_CLAUSE_CHAIN (c))
                if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
                    && OMP_CLAUSE_DECL (c) == decl)
                  break;

              if (c)
                return true;
            }
        }

      /* For tasks avoid using copy-in/out, unless they are readonly
         (in which case just copy-in is used).  As tasks can be
         deferred or executed in different thread, when GOMP_task
         returns, the task hasn't necessarily terminated.  */
      if (!TREE_READONLY (decl) && is_task_ctx (shared_ctx))
        {
          tree outer = maybe_lookup_decl_in_outer_ctx (decl, shared_ctx);
          if (is_gimple_reg (outer))
            {
              /* Taking address of OUTER in lower_send_shared_vars
                 might need regimplification of everything that uses the
                 variable.  */
              if (!task_shared_vars)
                task_shared_vars = BITMAP_ALLOC (NULL);
              bitmap_set_bit (task_shared_vars, DECL_UID (outer));
              TREE_ADDRESSABLE (outer) = 1;
            }
          return true;
        }
    }

  return false;
}

/* Create a new VAR_DECL and copy information from VAR to it.  */

tree
copy_var_decl (tree var, tree name, tree type)
{
  tree copy = build_decl (DECL_SOURCE_LOCATION (var), VAR_DECL, name, type);

  TREE_ADDRESSABLE (copy) = TREE_ADDRESSABLE (var);
  TREE_THIS_VOLATILE (copy) = TREE_THIS_VOLATILE (var);
  DECL_GIMPLE_REG_P (copy) = DECL_GIMPLE_REG_P (var);
  DECL_ARTIFICIAL (copy) = DECL_ARTIFICIAL (var);
  DECL_IGNORED_P (copy) = DECL_IGNORED_P (var);
  DECL_CONTEXT (copy) = DECL_CONTEXT (var);
  TREE_USED (copy) = 1;
  DECL_SEEN_IN_BIND_EXPR_P (copy) = 1;

  return copy;
}

/* Construct a new automatic decl similar to VAR.  */

static tree
omp_copy_decl_2 (tree var, tree name, tree type, omp_context *ctx)
{
  tree copy = copy_var_decl (var, name, type);

  DECL_CONTEXT (copy) = current_function_decl;
  TREE_CHAIN (copy) = ctx->block_vars;
  ctx->block_vars = copy;

  return copy;
}

static tree
omp_copy_decl_1 (tree var, omp_context *ctx)
{
  return omp_copy_decl_2 (var, DECL_NAME (var), TREE_TYPE (var), ctx);
}

/* Build tree nodes to access the field for VAR on the receiver side.  */

static tree
build_receiver_ref (tree var, bool by_ref, omp_context *ctx)
{
  tree x, field = lookup_field (var, ctx);

  /* If the receiver record type was remapped in the child function,
     remap the field into the new record type.  */
  x = maybe_lookup_field (field, ctx);
  if (x != NULL)
    field = x;

  x = build_fold_indirect_ref (ctx->receiver_decl);
  x = build3 (COMPONENT_REF, TREE_TYPE (field), x, field, NULL);
  if (by_ref)
    x = build_fold_indirect_ref (x);

  return x;
}

/* Build tree nodes to access VAR in the scope outer to CTX.  In the case
   of a parallel, this is a component reference; for workshare constructs
   this is some variable.  */

static tree
build_outer_var_ref (tree var, omp_context *ctx)
{
  tree x;

  if (is_global_var (maybe_lookup_decl_in_outer_ctx (var, ctx)))
    x = var;
  else if (is_variable_sized (var))
    {
      x = TREE_OPERAND (DECL_VALUE_EXPR (var), 0);
      x = build_outer_var_ref (x, ctx);
      x = build_fold_indirect_ref (x);
    }
  else if (is_taskreg_ctx (ctx))
    {
      bool by_ref = use_pointer_for_field (var, NULL);
      x = build_receiver_ref (var, by_ref, ctx);
    }
  else if (ctx->outer)
    x = lookup_decl (var, ctx->outer);
  else if (is_reference (var))
    /* This can happen with orphaned constructs.  If var is reference, it is
       possible it is shared and as such valid.  */
    x = var;
  else
    gcc_unreachable ();

  if (is_reference (var))
    x = build_fold_indirect_ref (x);

  return x;
}

/* Build tree nodes to access the field for VAR on the sender side.  */

static tree
build_sender_ref (tree var, omp_context *ctx)
{
  tree field = lookup_sfield (var, ctx);
  return build3 (COMPONENT_REF, TREE_TYPE (field),
                 ctx->sender_decl, field, NULL);
}

/* Add a new field for VAR inside the structure CTX->SENDER_DECL.  */

static void
install_var_field (tree var, bool by_ref, int mask, omp_context *ctx)
{
  tree field, type, sfield = NULL_TREE;

  gcc_assert ((mask & 1) == 0
              || !splay_tree_lookup (ctx->field_map, (splay_tree_key) var));
  gcc_assert ((mask & 2) == 0 || !ctx->sfield_map
              || !splay_tree_lookup (ctx->sfield_map, (splay_tree_key) var));

  type = TREE_TYPE (var);
  if (by_ref)
    type = build_pointer_type (type);
  else if ((mask & 3) == 1 && is_reference (var))
    type = TREE_TYPE (type);

  field = build_decl (DECL_SOURCE_LOCATION (var),
                      FIELD_DECL, DECL_NAME (var), type);

  /* Remember what variable this field was created for.  This does have a
     side effect of making dwarf2out ignore this member, so for helpful
     debugging we clear it later in delete_omp_context.  */
  DECL_ABSTRACT_ORIGIN (field) = var;
  if (type == TREE_TYPE (var))
    {
      DECL_ALIGN (field) = DECL_ALIGN (var);
      DECL_USER_ALIGN (field) = DECL_USER_ALIGN (var);
      TREE_THIS_VOLATILE (field) = TREE_THIS_VOLATILE (var);
    }
  else
    DECL_ALIGN (field) = TYPE_ALIGN (type);

  if ((mask & 3) == 3)
    {
      insert_field_into_struct (ctx->record_type, field);
      if (ctx->srecord_type)
        {
          sfield = build_decl (DECL_SOURCE_LOCATION (var),
                               FIELD_DECL, DECL_NAME (var), type);
          DECL_ABSTRACT_ORIGIN (sfield) = var;
          DECL_ALIGN (sfield) = DECL_ALIGN (field);
          DECL_USER_ALIGN (sfield) = DECL_USER_ALIGN (field);
          TREE_THIS_VOLATILE (sfield) = TREE_THIS_VOLATILE (field);
          insert_field_into_struct (ctx->srecord_type, sfield);
        }
    }
  else
    {
      if (ctx->srecord_type == NULL_TREE)
        {
          tree t;

          ctx->srecord_type = lang_hooks.types.make_type (RECORD_TYPE);
          ctx->sfield_map = splay_tree_new (splay_tree_compare_pointers, 0, 0);
          for (t = TYPE_FIELDS (ctx->record_type); t ; t = TREE_CHAIN (t))
            {
              sfield = build_decl (DECL_SOURCE_LOCATION (var),
                                   FIELD_DECL, DECL_NAME (t), TREE_TYPE (t));
              DECL_ABSTRACT_ORIGIN (sfield) = DECL_ABSTRACT_ORIGIN (t);
              insert_field_into_struct (ctx->srecord_type, sfield);
              splay_tree_insert (ctx->sfield_map,
                                 (splay_tree_key) DECL_ABSTRACT_ORIGIN (t),
                                 (splay_tree_value) sfield);
            }
        }
      sfield = field;
      insert_field_into_struct ((mask & 1) ? ctx->record_type
                                : ctx->srecord_type, field);
    }

  if (mask & 1)
    splay_tree_insert (ctx->field_map, (splay_tree_key) var,
                       (splay_tree_value) field);
  if ((mask & 2) && ctx->sfield_map)
    splay_tree_insert (ctx->sfield_map, (splay_tree_key) var,
                       (splay_tree_value) sfield);
}

static tree
install_var_local (tree var, omp_context *ctx)
{
  tree new_var = omp_copy_decl_1 (var, ctx);
  insert_decl_map (&ctx->cb, var, new_var);
  return new_var;
}

/* Adjust the replacement for DECL in CTX for the new context.  This means
   copying the DECL_VALUE_EXPR, and fixing up the type.  */

static void
fixup_remapped_decl (tree decl, omp_context *ctx, bool private_debug)
{
  tree new_decl, size;

  new_decl = lookup_decl (decl, ctx);

  TREE_TYPE (new_decl) = remap_type (TREE_TYPE (decl), &ctx->cb);

  if ((!TREE_CONSTANT (DECL_SIZE (new_decl)) || private_debug)
      && DECL_HAS_VALUE_EXPR_P (decl))
    {
      tree ve = DECL_VALUE_EXPR (decl);
      walk_tree (&ve, copy_tree_body_r, &ctx->cb, NULL);
      SET_DECL_VALUE_EXPR (new_decl, ve);
      DECL_HAS_VALUE_EXPR_P (new_decl) = 1;
    }

  if (!TREE_CONSTANT (DECL_SIZE (new_decl)))
    {
      size = remap_decl (DECL_SIZE (decl), &ctx->cb);
      if (size == error_mark_node)
        size = TYPE_SIZE (TREE_TYPE (new_decl));
      DECL_SIZE (new_decl) = size;

      size = remap_decl (DECL_SIZE_UNIT (decl), &ctx->cb);
      if (size == error_mark_node)
        size = TYPE_SIZE_UNIT (TREE_TYPE (new_decl));
      DECL_SIZE_UNIT (new_decl) = size;
    }
}

/* The callback for remap_decl.  Search all containing contexts for a
   mapping of the variable; this avoids having to duplicate the splay
   tree ahead of time.  We know a mapping doesn't already exist in the
   given context.  Create new mappings to implement default semantics.  */

static tree
omp_copy_decl (tree var, copy_body_data *cb)
{
  omp_context *ctx = (omp_context *) cb;
  tree new_var;

  if (TREE_CODE (var) == LABEL_DECL)
    {
      new_var = create_artificial_label (DECL_SOURCE_LOCATION (var));
      DECL_CONTEXT (new_var) = current_function_decl;
      insert_decl_map (&ctx->cb, var, new_var);
      return new_var;
    }

  while (!is_taskreg_ctx (ctx))
    {
      ctx = ctx->outer;
      if (ctx == NULL)
        return var;
      new_var = maybe_lookup_decl (var, ctx);
      if (new_var)
        return new_var;
    }

  if (is_global_var (var) || decl_function_context (var) != ctx->cb.src_fn)
    return var;

  return error_mark_node;
}


/* Return the parallel region associated with STMT.  */

/* Debugging dumps for parallel regions.  */
void dump_omp_region (FILE *, struct omp_region *, int);
void debug_omp_region (struct omp_region *);
void debug_all_omp_regions (void);

/* Dump the parallel region tree rooted at REGION.  */

void
dump_omp_region (FILE *file, struct omp_region *region, int indent)
{
  fprintf (file, "%*sbb %d: %s\n", indent, "", region->entry->index,
           gimple_code_name[region->type]);

  if (region->inner)
    dump_omp_region (file, region->inner, indent + 4);

  if (region->cont)
    {
      fprintf (file, "%*sbb %d: GIMPLE_OMP_CONTINUE\n", indent, "",
               region->cont->index);
    }
    
  if (region->exit)
    fprintf (file, "%*sbb %d: GIMPLE_OMP_RETURN\n", indent, "",
             region->exit->index);
  else
    fprintf (file, "%*s[no exit marker]\n", indent, "");

  if (region->next)
    dump_omp_region (file, region->next, indent);
}

void
debug_omp_region (struct omp_region *region)
{
  dump_omp_region (stderr, region, 0);
}

void
debug_all_omp_regions (void)
{
  dump_omp_region (stderr, root_omp_region, 0);
}


/* Create a new parallel region starting at STMT inside region PARENT.  */

struct omp_region *
new_omp_region (basic_block bb, enum gimple_code type,
                struct omp_region *parent)
{
  struct omp_region *region = XCNEW (struct omp_region);

  region->outer = parent;
  region->entry = bb;
  region->type = type;

  if (parent)
    {
      /* This is a nested region.  Add it to the list of inner
         regions in PARENT.  */
      region->next = parent->inner;
      parent->inner = region;
    }
  else
    {
      /* This is a toplevel region.  Add it to the list of toplevel
         regions in ROOT_OMP_REGION.  */
      region->next = root_omp_region;
      root_omp_region = region;
    }

  return region;
}

/* Release the memory associated with the region tree rooted at REGION.  */

static void
free_omp_region_1 (struct omp_region *region)
{
  struct omp_region *i, *n;

  for (i = region->inner; i ; i = n)
    {
      n = i->next;
      free_omp_region_1 (i);
    }

  free (region);
}

/* Release the memory for the entire omp region tree.  */

void
free_omp_regions (void)
{
  struct omp_region *r, *n;
  for (r = root_omp_region; r ; r = n)
    {
      n = r->next;
      free_omp_region_1 (r);
    }
  root_omp_region = NULL;
}


/* Create a new context, with OUTER_CTX being the surrounding context.  */

static omp_context *
new_omp_context (gimple stmt, omp_context *outer_ctx)
{
  omp_context *ctx = XCNEW (omp_context);

  splay_tree_insert (all_contexts, (splay_tree_key) stmt,
                     (splay_tree_value) ctx);
  ctx->stmt = stmt;

  if (outer_ctx)
    {
      ctx->outer = outer_ctx;
      ctx->cb = outer_ctx->cb;
      ctx->cb.block = NULL;
      ctx->depth = outer_ctx->depth + 1;
    }
  else
    {
      ctx->cb.src_fn = current_function_decl;
      ctx->cb.dst_fn = current_function_decl;
      ctx->cb.src_node = cgraph_node (current_function_decl);
      ctx->cb.dst_node = ctx->cb.src_node;
      ctx->cb.src_cfun = cfun;
      ctx->cb.copy_decl = omp_copy_decl;
      ctx->cb.eh_region = -1;
      ctx->cb.transform_call_graph_edges = CB_CGE_MOVE;
      ctx->depth = 1;
    }

  ctx->cb.decl_map = pointer_map_create ();

  return ctx;
}

static gimple_seq maybe_catch_exception (gimple_seq);

/* Finalize task copyfn.  */

static void
finalize_task_copyfn (gimple task_stmt)
{
  struct function *child_cfun;
  tree child_fn, old_fn;
  gimple_seq seq, new_seq;
  gimple bind;

  child_fn = gimple_omp_task_copy_fn (task_stmt);
  if (child_fn == NULL_TREE)
    return;

  child_cfun = DECL_STRUCT_FUNCTION (child_fn);

  /* Inform the callgraph about the new function.  */
  DECL_STRUCT_FUNCTION (child_fn)->curr_properties
    = cfun->curr_properties;

  old_fn = current_function_decl;
  push_cfun (child_cfun);
  current_function_decl = child_fn;
  bind = gimplify_body (&DECL_SAVED_TREE (child_fn), child_fn, false);
  seq = gimple_seq_alloc ();
  gimple_seq_add_stmt (&seq, bind);
  new_seq = maybe_catch_exception (seq);
  if (new_seq != seq)
    {
      bind = gimple_build_bind (NULL, new_seq, NULL);
      seq = gimple_seq_alloc ();
      gimple_seq_add_stmt (&seq, bind);
    }
  gimple_set_body (child_fn, seq);
  pop_cfun ();
  current_function_decl = old_fn;

  cgraph_add_new_function (child_fn, false);
}

/* Destroy a omp_context data structures.  Called through the splay tree
   value delete callback.  */

static void
delete_omp_context (splay_tree_value value)
{
  omp_context *ctx = (omp_context *) value;

  pointer_map_destroy (ctx->cb.decl_map);

  if (ctx->field_map)
    splay_tree_delete (ctx->field_map);
  if (ctx->sfield_map)
    splay_tree_delete (ctx->sfield_map);

  /* We hijacked DECL_ABSTRACT_ORIGIN earlier.  We need to clear it before
     it produces corrupt debug information.  */
  if (ctx->record_type)
    {
      tree t;
      for (t = TYPE_FIELDS (ctx->record_type); t ; t = TREE_CHAIN (t))
        DECL_ABSTRACT_ORIGIN (t) = NULL;
    }
  if (ctx->srecord_type)
    {
      tree t;
      for (t = TYPE_FIELDS (ctx->srecord_type); t ; t = TREE_CHAIN (t))
        DECL_ABSTRACT_ORIGIN (t) = NULL;
    }

  if (is_task_ctx (ctx))
    finalize_task_copyfn (ctx->stmt);

  XDELETE (ctx);
}

/* Fix up RECEIVER_DECL with a type that has been remapped to the child
   context.  */

static void
fixup_child_record_type (omp_context *ctx)
{
  tree f, type = ctx->record_type;

  /* ??? It isn't sufficient to just call remap_type here, because
     variably_modified_type_p doesn't work the way we expect for
     record types.  Testing each field for whether it needs remapping
     and creating a new record by hand works, however.  */
  for (f = TYPE_FIELDS (type); f ; f = TREE_CHAIN (f))
    if (variably_modified_type_p (TREE_TYPE (f), ctx->cb.src_fn))
      break;
  if (f)
    {
      tree name, new_fields = NULL;

      type = lang_hooks.types.make_type (RECORD_TYPE);
      name = DECL_NAME (TYPE_NAME (ctx->record_type));
      name = build_decl (DECL_SOURCE_LOCATION (ctx->receiver_decl),
                         TYPE_DECL, name, type);
      TYPE_NAME (type) = name;

      for (f = TYPE_FIELDS (ctx->record_type); f ; f = TREE_CHAIN (f))
        {
          tree new_f = copy_node (f);
          DECL_CONTEXT (new_f) = type;
          TREE_TYPE (new_f) = remap_type (TREE_TYPE (f), &ctx->cb);
          TREE_CHAIN (new_f) = new_fields;
          walk_tree (&DECL_SIZE (new_f), copy_tree_body_r, &ctx->cb, NULL);
          walk_tree (&DECL_SIZE_UNIT (new_f), copy_tree_body_r,
                     &ctx->cb, NULL);
          walk_tree (&DECL_FIELD_OFFSET (new_f), copy_tree_body_r,
                     &ctx->cb, NULL);
          new_fields = new_f;

          /* Arrange to be able to look up the receiver field
             given the sender field.  */
          splay_tree_insert (ctx->field_map, (splay_tree_key) f,
                             (splay_tree_value) new_f);
        }
      TYPE_FIELDS (type) = nreverse (new_fields);
      layout_type (type);
    }

  TREE_TYPE (ctx->receiver_decl) = build_pointer_type (type);
}

/* Instantiate decls as necessary in CTX to satisfy the data sharing
   specified by CLAUSES.  */

static void
scan_sharing_clauses (tree clauses, omp_context *ctx)
{
  tree c, decl;
  bool scan_array_reductions = false;

  for (c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
    {
      bool by_ref;

      switch (OMP_CLAUSE_CODE (c))
        {
        case OMP_CLAUSE_PRIVATE:
          decl = OMP_CLAUSE_DECL (c);
          if (OMP_CLAUSE_PRIVATE_OUTER_REF (c))
            goto do_private;
          else if (!is_variable_sized (decl))
            install_var_local (decl, ctx);
          break;

        case OMP_CLAUSE_SHARED:
          gcc_assert (is_taskreg_ctx (ctx));
          decl = OMP_CLAUSE_DECL (c);
          gcc_assert (!COMPLETE_TYPE_P (TREE_TYPE (decl))
                      || !is_variable_sized (decl));
          /* Global variables don't need to be copied,
             the receiver side will use them directly.  */
          if (is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx)))
            break;
          by_ref = use_pointer_for_field (decl, ctx);
          if (! TREE_READONLY (decl)
              || TREE_ADDRESSABLE (decl)
              || by_ref
              || is_reference (decl))
            {
              install_var_field (decl, by_ref, 3, ctx);
              install_var_local (decl, ctx);
              break;
            }
          /* We don't need to copy const scalar vars back.  */
          OMP_CLAUSE_SET_CODE (c, OMP_CLAUSE_FIRSTPRIVATE);
          goto do_private;

        case OMP_CLAUSE_LASTPRIVATE:
          /* Let the corresponding firstprivate clause create
             the variable.  */
          if (OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE (c))
            break;
          /* FALLTHRU */

        case OMP_CLAUSE_FIRSTPRIVATE:
        case OMP_CLAUSE_REDUCTION:
          decl = OMP_CLAUSE_DECL (c);
        do_private:
          if (is_variable_sized (decl))
            {
              if (is_task_ctx (ctx))
                install_var_field (decl, false, 1, ctx);
              break;
            }
          else if (is_taskreg_ctx (ctx))
            {
              bool global
                = is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx));
              by_ref = use_pointer_for_field (decl, NULL);

              if (is_task_ctx (ctx)
                  && (global || by_ref || is_reference (decl)))
                {
                  install_var_field (decl, false, 1, ctx);
                  if (!global)
                    install_var_field (decl, by_ref, 2, ctx);
                }
              else if (!global)
                install_var_field (decl, by_ref, 3, ctx);
            }
          install_var_local (decl, ctx);
          break;

        case OMP_CLAUSE_COPYPRIVATE:
          if (ctx->outer)
            scan_omp_op (&OMP_CLAUSE_DECL (c), ctx->outer);
          /* FALLTHRU */

        case OMP_CLAUSE_COPYIN:
          decl = OMP_CLAUSE_DECL (c);
          by_ref = use_pointer_for_field (decl, NULL);
          install_var_field (decl, by_ref, 3, ctx);
          break;

        case OMP_CLAUSE_DEFAULT:
          ctx->default_kind = OMP_CLAUSE_DEFAULT_KIND (c);
          break;

        case OMP_CLAUSE_IF:
        case OMP_CLAUSE_NUM_THREADS:
        case OMP_CLAUSE_SCHEDULE:
          if (ctx->outer)
            scan_omp_op (&OMP_CLAUSE_OPERAND (c, 0), ctx->outer);
          break;

        case OMP_CLAUSE_NOWAIT:
        case OMP_CLAUSE_ORDERED:
        case OMP_CLAUSE_COLLAPSE:
        case OMP_CLAUSE_UNTIED:
          break;

        default:
          gcc_unreachable ();
        }
    }

  for (c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
    {
      switch (OMP_CLAUSE_CODE (c))
        {
        case OMP_CLAUSE_LASTPRIVATE:
          /* Let the corresponding firstprivate clause create
             the variable.  */
          if (OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c))
            scan_array_reductions = true;
          if (OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE (c))
            break;
          /* FALLTHRU */

        case OMP_CLAUSE_PRIVATE:
        case OMP_CLAUSE_FIRSTPRIVATE:
        case OMP_CLAUSE_REDUCTION:
          decl = OMP_CLAUSE_DECL (c);
          if (is_variable_sized (decl))
            install_var_local (decl, ctx);
          fixup_remapped_decl (decl, ctx,
                               OMP_CLAUSE_CODE (c) == OMP_CLAUSE_PRIVATE
                               && OMP_CLAUSE_PRIVATE_DEBUG (c));
          if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION
              && OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
            scan_array_reductions = true;
          break;

        case OMP_CLAUSE_SHARED:
          decl = OMP_CLAUSE_DECL (c);
          if (! is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx)))
            fixup_remapped_decl (decl, ctx, false);
          break;

        case OMP_CLAUSE_COPYPRIVATE:
        case OMP_CLAUSE_COPYIN:
        case OMP_CLAUSE_DEFAULT:
        case OMP_CLAUSE_IF:
        case OMP_CLAUSE_NUM_THREADS:
        case OMP_CLAUSE_SCHEDULE:
        case OMP_CLAUSE_NOWAIT:
        case OMP_CLAUSE_ORDERED:
        case OMP_CLAUSE_COLLAPSE:
        case OMP_CLAUSE_UNTIED:
          break;

        default:
          gcc_unreachable ();
        }
    }

  if (scan_array_reductions)
    for (c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION
          && OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
        {
          scan_omp (OMP_CLAUSE_REDUCTION_GIMPLE_INIT (c), ctx);
          scan_omp (OMP_CLAUSE_REDUCTION_GIMPLE_MERGE (c), ctx);
        }
      else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LASTPRIVATE
               && OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c))
        scan_omp (OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c), ctx);
}

/* Create a new name for omp child function.  Returns an identifier.  */

static GTY(()) unsigned int tmp_ompfn_id_num;

static tree
create_omp_child_function_name (bool task_copy)
{
  tree name = DECL_ASSEMBLER_NAME (current_function_decl);
  size_t len = IDENTIFIER_LENGTH (name);
  char *tmp_name, *prefix;
  const char *suffix;

  suffix = task_copy ? "_omp_cpyfn" : "_omp_fn";
  prefix = XALLOCAVEC (char, len + strlen (suffix) + 1);
  memcpy (prefix, IDENTIFIER_POINTER (name), len);
  strcpy (prefix + len, suffix);
#ifndef NO_DOT_IN_LABEL
  prefix[len] = '.';
#elif !defined NO_DOLLAR_IN_LABEL
  prefix[len] = '$';
#endif
  ASM_FORMAT_PRIVATE_NAME (tmp_name, prefix, tmp_ompfn_id_num++);
  return get_identifier (tmp_name);
}

/* Build a decl for the omp child function.  It'll not contain a body
   yet, just the bare decl.  */

static void
create_omp_child_function (omp_context *ctx, bool task_copy)
{
  tree decl, type, name, t;

  name = create_omp_child_function_name (task_copy);
  if (task_copy)
    type = build_function_type_list (void_type_node, ptr_type_node,
                                     ptr_type_node, NULL_TREE);
  else
    type = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);

  decl = build_decl (gimple_location (ctx->stmt),
                     FUNCTION_DECL, name, type);

  if (!task_copy)
    ctx->cb.dst_fn = decl;
  else
    gimple_omp_task_set_copy_fn (ctx->stmt, decl);

  TREE_STATIC (decl) = 1;
  TREE_USED (decl) = 1;
  DECL_ARTIFICIAL (decl) = 1;
  DECL_IGNORED_P (decl) = 0;
  TREE_PUBLIC (decl) = 0;
  DECL_UNINLINABLE (decl) = 1;
  DECL_EXTERNAL (decl) = 0;
  DECL_CONTEXT (decl) = NULL_TREE;
  DECL_INITIAL (decl) = make_node (BLOCK);

  t = build_decl (DECL_SOURCE_LOCATION (decl),
                  RESULT_DECL, NULL_TREE, void_type_node);
  DECL_ARTIFICIAL (t) = 1;
  DECL_IGNORED_P (t) = 1;
  DECL_CONTEXT (t) = decl;
  DECL_RESULT (decl) = t;

  t = build_decl (DECL_SOURCE_LOCATION (decl),
                  PARM_DECL, get_identifier (".omp_data_i"), ptr_type_node);
  DECL_ARTIFICIAL (t) = 1;
  DECL_ARG_TYPE (t) = ptr_type_node;
  DECL_CONTEXT (t) = current_function_decl;
  TREE_USED (t) = 1;
  DECL_ARGUMENTS (decl) = t;
  if (!task_copy)
    ctx->receiver_decl = t;
  else
    {
      t = build_decl (DECL_SOURCE_LOCATION (decl),
                      PARM_DECL, get_identifier (".omp_data_o"),
                      ptr_type_node);
      DECL_ARTIFICIAL (t) = 1;
      DECL_ARG_TYPE (t) = ptr_type_node;
      DECL_CONTEXT (t) = current_function_decl;
      TREE_USED (t) = 1;
      TREE_ADDRESSABLE (t) = 1;
      TREE_CHAIN (t) = DECL_ARGUMENTS (decl);
      DECL_ARGUMENTS (decl) = t;
    }

  /* Allocate memory for the function structure.  The call to 
     allocate_struct_function clobbers CFUN, so we need to restore
     it afterward.  */
  push_struct_function (decl);
  cfun->function_end_locus = gimple_location (ctx->stmt);
  pop_cfun ();
}


/* Scan an OpenMP parallel directive.  */

static void
scan_omp_parallel (gimple_stmt_iterator *gsi, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name;
  gimple stmt = gsi_stmt (*gsi);

  /* Ignore parallel directives with empty bodies, unless there
     are copyin clauses.  */
  if (optimize > 0
      && empty_body_p (gimple_omp_body (stmt))
      && find_omp_clause (gimple_omp_parallel_clauses (stmt),
                          OMP_CLAUSE_COPYIN) == NULL)
    {
      gsi_replace (gsi, gimple_build_nop (), false);
      return;
    }

  ctx = new_omp_context (stmt, outer_ctx);
  if (taskreg_nesting_level > 1)
    ctx->is_nested = true;
  ctx->field_map = splay_tree_new (splay_tree_compare_pointers, 0, 0);
  ctx->default_kind = OMP_CLAUSE_DEFAULT_SHARED;
  ctx->record_type = lang_hooks.types.make_type (RECORD_TYPE);
  name = create_tmp_var_name (".omp_data_s");
  name = build_decl (gimple_location (stmt),
                     TYPE_DECL, name, ctx->record_type);
  TYPE_NAME (ctx->record_type) = name;
  create_omp_child_function (ctx, false);
  gimple_omp_parallel_set_child_fn (stmt, ctx->cb.dst_fn);

  scan_sharing_clauses (gimple_omp_parallel_clauses (stmt), ctx);
  scan_omp (gimple_omp_body (stmt), ctx);

  if (TYPE_FIELDS (ctx->record_type) == NULL)
    ctx->record_type = ctx->receiver_decl = NULL;
  else
    {
      layout_type (ctx->record_type);
      fixup_child_record_type (ctx);
    }
}

/* Scan an OpenMP task directive.  */

static void
scan_omp_task (gimple_stmt_iterator *gsi, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name, t;
  gimple stmt = gsi_stmt (*gsi);
  location_t loc = gimple_location (stmt);

  /* Ignore task directives with empty bodies.  */
  if (optimize > 0
      && empty_body_p (gimple_omp_body (stmt)))
    {
      gsi_replace (gsi, gimple_build_nop (), false);
      return;
    }

  ctx = new_omp_context (stmt, outer_ctx);
  if (taskreg_nesting_level > 1)
    ctx->is_nested = true;
  ctx->field_map = splay_tree_new (splay_tree_compare_pointers, 0, 0);
  ctx->default_kind = OMP_CLAUSE_DEFAULT_SHARED;
  ctx->record_type = lang_hooks.types.make_type (RECORD_TYPE);
  name = create_tmp_var_name (".omp_data_s");
  name = build_decl (gimple_location (stmt),
                     TYPE_DECL, name, ctx->record_type);
  TYPE_NAME (ctx->record_type) = name;
  create_omp_child_function (ctx, false);
  gimple_omp_task_set_child_fn (stmt, ctx->cb.dst_fn);

  scan_sharing_clauses (gimple_omp_task_clauses (stmt), ctx);

  if (ctx->srecord_type)
    {
      name = create_tmp_var_name (".omp_data_a");
      name = build_decl (gimple_location (stmt),
                         TYPE_DECL, name, ctx->srecord_type);
      TYPE_NAME (ctx->srecord_type) = name;
      create_omp_child_function (ctx, true);
    }

  scan_omp (gimple_omp_body (stmt), ctx);

  if (TYPE_FIELDS (ctx->record_type) == NULL)
    {
      ctx->record_type = ctx->receiver_decl = NULL;
      t = build_int_cst (long_integer_type_node, 0);
      gimple_omp_task_set_arg_size (stmt, t);
      t = build_int_cst (long_integer_type_node, 1);
      gimple_omp_task_set_arg_align (stmt, t);
    }
  else
    {
      tree *p, vla_fields = NULL_TREE, *q = &vla_fields;
      /* Move VLA fields to the end.  */
      p = &TYPE_FIELDS (ctx->record_type);
      while (*p)
        if (!TYPE_SIZE_UNIT (TREE_TYPE (*p))
            || ! TREE_CONSTANT (TYPE_SIZE_UNIT (TREE_TYPE (*p))))
          {
            *q = *p;
            *p = TREE_CHAIN (*p);
            TREE_CHAIN (*q) = NULL_TREE;
            q = &TREE_CHAIN (*q);
          }
        else
          p = &TREE_CHAIN (*p);
      *p = vla_fields;
      layout_type (ctx->record_type);
      fixup_child_record_type (ctx);
      if (ctx->srecord_type)
        layout_type (ctx->srecord_type);
      t = fold_convert_loc (loc, long_integer_type_node,
                        TYPE_SIZE_UNIT (ctx->record_type));
      gimple_omp_task_set_arg_size (stmt, t);
      t = build_int_cst (long_integer_type_node,
                         TYPE_ALIGN_UNIT (ctx->record_type));
      gimple_omp_task_set_arg_align (stmt, t);
    }
}


/* Scan an OpenMP loop directive.  */

static void
scan_omp_for (gimple stmt, omp_context *outer_ctx)
{
  omp_context *ctx;
  size_t i;

  ctx = new_omp_context (stmt, outer_ctx);

  scan_sharing_clauses (gimple_omp_for_clauses (stmt), ctx);

  scan_omp (gimple_omp_for_pre_body (stmt), ctx);
  for (i = 0; i < gimple_omp_for_collapse (stmt); i++)
    {
      scan_omp_op (gimple_omp_for_index_ptr (stmt, i), ctx);
      scan_omp_op (gimple_omp_for_initial_ptr (stmt, i), ctx);
      scan_omp_op (gimple_omp_for_final_ptr (stmt, i), ctx);
      scan_omp_op (gimple_omp_for_incr_ptr (stmt, i), ctx);
    }
  scan_omp (gimple_omp_body (stmt), ctx);
}

/* Scan an OpenMP sections directive.  */

static void
scan_omp_sections (gimple stmt, omp_context *outer_ctx)
{
  omp_context *ctx;

  ctx = new_omp_context (stmt, outer_ctx);
  scan_sharing_clauses (gimple_omp_sections_clauses (stmt), ctx);
  scan_omp (gimple_omp_body (stmt), ctx);
}

/* Scan an OpenMP single directive.  */

static void
scan_omp_single (gimple stmt, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name;

  ctx = new_omp_context (stmt, outer_ctx);
  ctx->field_map = splay_tree_new (splay_tree_compare_pointers, 0, 0);
  ctx->record_type = lang_hooks.types.make_type (RECORD_TYPE);
  name = create_tmp_var_name (".omp_copy_s");
  name = build_decl (gimple_location (stmt),
                     TYPE_DECL, name, ctx->record_type);
  TYPE_NAME (ctx->record_type) = name;

  scan_sharing_clauses (gimple_omp_single_clauses (stmt), ctx);
  scan_omp (gimple_omp_body (stmt), ctx);

  if (TYPE_FIELDS (ctx->record_type) == NULL)
    ctx->record_type = NULL;
  else
    layout_type (ctx->record_type);
}


/* Check OpenMP nesting restrictions.  */
static void
check_omp_nesting_restrictions (gimple  stmt, omp_context *ctx)
{
  switch (gimple_code (stmt))
    {
    case GIMPLE_OMP_FOR:
    case GIMPLE_OMP_SECTIONS:
    case GIMPLE_OMP_SINGLE:
    case GIMPLE_CALL:
      for (; ctx != NULL; ctx = ctx->outer)
        switch (gimple_code (ctx->stmt))
          {
          case GIMPLE_OMP_FOR:
          case GIMPLE_OMP_SECTIONS:
          case GIMPLE_OMP_SINGLE:
          case GIMPLE_OMP_ORDERED:
          case GIMPLE_OMP_MASTER:
          case GIMPLE_OMP_TASK:
            if (is_gimple_call (stmt))
              {
                warning (0, "barrier region may not be closely nested inside "
                            "of work-sharing, critical, ordered, master or "
                            "explicit task region");
                return;
              }
            warning (0, "work-sharing region may not be closely nested inside "
                        "of work-sharing, critical, ordered, master or explicit "
                        "task region");
            return;
          case GIMPLE_OMP_PARALLEL:
            return;
          default:
            break;
          }
      break;
    case GIMPLE_OMP_MASTER:
      for (; ctx != NULL; ctx = ctx->outer)
        switch (gimple_code (ctx->stmt))
          {
          case GIMPLE_OMP_FOR:
          case GIMPLE_OMP_SECTIONS:
          case GIMPLE_OMP_SINGLE:
          case GIMPLE_OMP_TASK:
            warning (0, "master region may not be closely nested inside "
                        "of work-sharing or explicit task region");
            return;
          case GIMPLE_OMP_PARALLEL:
            return;
          default:
            break;
          }
      break;
    case GIMPLE_OMP_ORDERED:
      for (; ctx != NULL; ctx = ctx->outer)
        switch (gimple_code (ctx->stmt))
          {
          case GIMPLE_OMP_CRITICAL:
          case GIMPLE_OMP_TASK:
            warning (0, "ordered region may not be closely nested inside "
                        "of critical or explicit task region");
            return;
          case GIMPLE_OMP_FOR:
            if (find_omp_clause (gimple_omp_for_clauses (ctx->stmt),
                                 OMP_CLAUSE_ORDERED) == NULL)
              warning (0, "ordered region must be closely nested inside "
                          "a loop region with an ordered clause");
            return;
          case GIMPLE_OMP_PARALLEL:
            return;
          default:
            break;
          }
      break;
    case GIMPLE_OMP_CRITICAL:
      for (; ctx != NULL; ctx = ctx->outer)
        if (gimple_code (ctx->stmt) == GIMPLE_OMP_CRITICAL
            && (gimple_omp_critical_name (stmt)
                == gimple_omp_critical_name (ctx->stmt)))
          {
            warning (0, "critical region may not be nested inside a critical "
                        "region with the same name");
            return;
          }
      break;
    default:
      break;
    }
}


/* Helper function scan_omp.

   Callback for walk_tree or operators in walk_gimple_stmt used to
   scan for OpenMP directives in TP.  */

static tree
scan_omp_1_op (tree *tp, int *walk_subtrees, void *data)
{
  struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
  omp_context *ctx = (omp_context *) wi->info;
  tree t = *tp;

  switch (TREE_CODE (t))
    {
    case VAR_DECL:
    case PARM_DECL:
    case LABEL_DECL:
    case RESULT_DECL:
      if (ctx)
        *tp = remap_decl (t, &ctx->cb);
      break;

    default:
      if (ctx && TYPE_P (t))
        *tp = remap_type (t, &ctx->cb);
      else if (!DECL_P (t))
        {
          *walk_subtrees = 1;
          if (ctx)
            TREE_TYPE (t) = remap_type (TREE_TYPE (t), &ctx->cb);
        }
      break;
    }

  return NULL_TREE;
}


/* Helper function for scan_omp.

   Callback for walk_gimple_stmt used to scan for OpenMP directives in
   the current statement in GSI.  */

static tree
scan_omp_1_stmt (gimple_stmt_iterator *gsi, bool *handled_ops_p,
                 struct walk_stmt_info *wi)
{
  gimple stmt = gsi_stmt (*gsi);
  omp_context *ctx = (omp_context *) wi->info;

  if (gimple_has_location (stmt))
    input_location = gimple_location (stmt);

  /* Check the OpenMP nesting restrictions.  */
  if (ctx != NULL)
    {
      if (is_gimple_omp (stmt))
        check_omp_nesting_restrictions (stmt, ctx);
      else if (is_gimple_call (stmt))
        {
          tree fndecl = gimple_call_fndecl (stmt);
          if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
              && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_GOMP_BARRIER)
            check_omp_nesting_restrictions (stmt, ctx);
        }
    }

  *handled_ops_p = true;

  switch (gimple_code (stmt))
    {
    case GIMPLE_OMP_PARALLEL:
      taskreg_nesting_level++;
      scan_omp_parallel (gsi, ctx);
      taskreg_nesting_level--;
      break;

    case GIMPLE_OMP_TASK:
      taskreg_nesting_level++;
      scan_omp_task (gsi, ctx);
      taskreg_nesting_level--;
      break;

    case GIMPLE_OMP_FOR:
      scan_omp_for (stmt, ctx);
      break;

    case GIMPLE_OMP_SECTIONS:
      scan_omp_sections (stmt, ctx);
      break;

    case GIMPLE_OMP_SINGLE:
      scan_omp_single (stmt, ctx);
      break;

    case GIMPLE_OMP_SECTION:
    case GIMPLE_OMP_MASTER:
    case GIMPLE_OMP_ORDERED:
    case GIMPLE_OMP_CRITICAL:
      ctx = new_omp_context (stmt, ctx);
      scan_omp (gimple_omp_body (stmt), ctx);
      break;

    case GIMPLE_BIND:
      {
        tree var;

        *handled_ops_p = false;
        if (ctx)
          for (var = gimple_bind_vars (stmt); var ; var = TREE_CHAIN (var))
            insert_decl_map (&ctx->cb, var, var);
      }
      break;
    default:
      *handled_ops_p = false;
      break;
    }

  return NULL_TREE;
}


/* Scan all the statements starting at the current statement.  CTX
   contains context information about the OpenMP directives and
   clauses found during the scan.  */

static void
scan_omp (gimple_seq body, omp_context *ctx)
{
  location_t saved_location;
  struct walk_stmt_info wi;

  memset (&wi, 0, sizeof (wi));
  wi.info = ctx;
  wi.want_locations = true;

  saved_location = input_location;
  walk_gimple_seq (body, scan_omp_1_stmt, scan_omp_1_op, &wi);
  input_location = saved_location;
}
\f
/* Re-gimplification and code generation routines.  */

/* Build a call to GOMP_barrier.  */

static tree
build_omp_barrier (void)
{
  return build_call_expr (built_in_decls[BUILT_IN_GOMP_BARRIER], 0);
}

/* If a context was created for STMT when it was scanned, return it.  */

static omp_context *
maybe_lookup_ctx (gimple stmt)
{
  splay_tree_node n;
  n = splay_tree_lookup (all_contexts, (splay_tree_key) stmt);
  return n ? (omp_context *) n->value : NULL;
}


/* Find the mapping for DECL in CTX or the immediately enclosing
   context that has a mapping for DECL.

   If CTX is a nested parallel directive, we may have to use the decl
   mappings created in CTX's parent context.  Suppose that we have the
   following parallel nesting (variable UIDs showed for clarity):

        iD.1562 = 0;
        #omp parallel shared(iD.1562)           -> outer parallel
          iD.1562 = iD.1562 + 1;

          #omp parallel shared (iD.1562)        -> inner parallel
             iD.1562 = iD.1562 - 1;

   Each parallel structure will create a distinct .omp_data_s structure
   for copying iD.1562 in/out of the directive:

        outer parallel          .omp_data_s.1.i -> iD.1562
        inner parallel          .omp_data_s.2.i -> iD.1562

   A shared variable mapping will produce a copy-out operation before
   the parallel directive and a copy-in operation after it.  So, in
   this case we would have:

        iD.1562 = 0;
        .omp_data_o.1.i = iD.1562;
        #omp parallel shared(iD.1562)           -> outer parallel
          .omp_data_i.1 = &.omp_data_o.1
          .omp_data_i.1->i = .omp_data_i.1->i + 1;

          .omp_data_o.2.i = iD.1562;            -> **
          #omp parallel shared(iD.1562)         -> inner parallel
            .omp_data_i.2 = &.omp_data_o.2
            .omp_data_i.2->i = .omp_data_i.2->i - 1;


    ** This is a problem.  The symbol iD.1562 cannot be referenced
       inside the body of the outer parallel region.  But since we are
       emitting this copy operation while expanding the inner parallel
       directive, we need to access the CTX structure of the outer
       parallel directive to get the correct mapping:

          .omp_data_o.2.i = .omp_data_i.1->i

    Since there may be other workshare or parallel directives enclosing
    the parallel directive, it may be necessary to walk up the context
    parent chain.  This is not a problem in general because nested
    parallelism happens only rarely.  */

static tree
lookup_decl_in_outer_ctx (tree decl, omp_context *ctx)
{
  tree t;
  omp_context *up;

  for (up = ctx->outer, t = NULL; up && t == NULL; up = up->outer)
    t = maybe_lookup_decl (decl, up);

  gcc_assert (!ctx->is_nested || t || is_global_var (decl));

  return t ? t : decl;
}


/* Similar to lookup_decl_in_outer_ctx, but return DECL if not found
   in outer contexts.  */

static tree
maybe_lookup_decl_in_outer_ctx (tree decl, omp_context *ctx)
{
  tree t = NULL;
  omp_context *up;

  for (up = ctx->outer, t = NULL; up && t == NULL; up = up->outer)
    t = maybe_lookup_decl (decl, up);

  return t ? t : decl;
}


/* Construct the initialization value for reduction CLAUSE.  */

tree
omp_reduction_init (tree clause, tree type)
{
  location_t loc = OMP_CLAUSE_LOCATION (clause);
  switch (OMP_CLAUSE_REDUCTION_CODE (clause))
    {
    case PLUS_EXPR:
    case MINUS_EXPR:
    case BIT_IOR_EXPR:
    case BIT_XOR_EXPR:
    case TRUTH_OR_EXPR:
    case TRUTH_ORIF_EXPR:
    case TRUTH_XOR_EXPR:
    case NE_EXPR:
      return fold_convert_loc (loc, type, integer_zero_node);

    case MULT_EXPR:
    case TRUTH_AND_EXPR:
    case TRUTH_ANDIF_EXPR:
    case EQ_EXPR:
      return fold_convert_loc (loc, type, integer_one_node);

    case BIT_AND_EXPR:
      return fold_convert_loc (loc, type, integer_minus_one_node);

    case MAX_EXPR:
      if (SCALAR_FLOAT_TYPE_P (type))
        {
          REAL_VALUE_TYPE max, min;
          if (HONOR_INFINITIES (TYPE_MODE (type)))
            {
              real_inf (&max);
              real_arithmetic (&min, NEGATE_EXPR, &max, NULL);
            }
          else
            real_maxval (&min, 1, TYPE_MODE (type));
          return build_real (type, min);
        }
      else
        {
          gcc_assert (INTEGRAL_TYPE_P (type));
          return TYPE_MIN_VALUE (type);
        }

    case MIN_EXPR:
      if (SCALAR_FLOAT_TYPE_P (type))
        {
          REAL_VALUE_TYPE max;
          if (HONOR_INFINITIES (TYPE_MODE (type)))
            real_inf (&max);
          else
            real_maxval (&max, 0, TYPE_MODE (type));
          return build_real (type, max);
        }
      else
        {
          gcc_assert (INTEGRAL_TYPE_P (type));
          return TYPE_MAX_VALUE (type);
        }

    default:
      gcc_unreachable ();
    }
}

/* Generate code to implement the input clauses, FIRSTPRIVATE and COPYIN,
   from the receiver (aka child) side and initializers for REFERENCE_TYPE
   private variables.  Initialization statements go in ILIST, while calls
   to destructors go in DLIST.  */

static void
lower_rec_input_clauses (tree clauses, gimple_seq *ilist, gimple_seq *dlist,
                         omp_context *ctx)
{
  gimple_stmt_iterator diter;
  tree c, dtor, copyin_seq, x, ptr;
  bool copyin_by_ref = false;
  bool lastprivate_firstprivate = false;
  int pass;

  *dlist = gimple_seq_alloc ();
  diter = gsi_start (*dlist);
  copyin_seq = NULL;

  /* Do all the fixed sized types in the first pass, and the variable sized
     types in the second pass.  This makes sure that the scalar arguments to
     the variable sized types are processed before we use them in the 
     variable sized operations.  */
  for (pass = 0; pass < 2; ++pass)
    {
      for (c = clauses; c ; c = OMP_CLAUSE_CHAIN (c))
        {
          enum omp_clause_code c_kind = OMP_CLAUSE_CODE (c);
          tree var, new_var;
          bool by_ref;
          location_t clause_loc = OMP_CLAUSE_LOCATION (c);

          switch (c_kind)
            {
            case OMP_CLAUSE_PRIVATE:
              if (OMP_CLAUSE_PRIVATE_DEBUG (c))
                continue;
              break;
            case OMP_CLAUSE_SHARED:
              if (maybe_lookup_decl (OMP_CLAUSE_DECL (c), ctx) == NULL)
                {
                  gcc_assert (is_global_var (OMP_CLAUSE_DECL (c)));
                  continue;
                }
            case OMP_CLAUSE_FIRSTPRIVATE:
            case OMP_CLAUSE_COPYIN:
            case OMP_CLAUSE_REDUCTION:
              break;
            case OMP_CLAUSE_LASTPRIVATE:
              if (OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE (c))
                {
                  lastprivate_firstprivate = true;
                  if (pass != 0)
                    continue;
                }
              break;
            default:
              continue;
            }

          new_var = var = OMP_CLAUSE_DECL (c);
          if (c_kind != OMP_CLAUSE_COPYIN)
            new_var = lookup_decl (var, ctx);

          if (c_kind == OMP_CLAUSE_SHARED || c_kind == OMP_CLAUSE_COPYIN)
            {
              if (pass != 0)
                continue;
            }
          else if (is_variable_sized (var))
            {
              /* For variable sized types, we need to allocate the
                 actual storage here.  Call alloca and store the
                 result in the pointer decl that we created elsewhere.  */
              if (pass == 0)
                continue;

              if (c_kind != OMP_CLAUSE_FIRSTPRIVATE || !is_task_ctx (ctx))
                {
                  gimple stmt;
                  tree tmp;

                  ptr = DECL_VALUE_EXPR (new_var);
                  gcc_assert (TREE_CODE (ptr) == INDIRECT_REF);
                  ptr = TREE_OPERAND (ptr, 0);
                  gcc_assert (DECL_P (ptr));
                  x = TYPE_SIZE_UNIT (TREE_TYPE (new_var));

                  /* void *tmp = __builtin_alloca */
                  stmt
                    = gimple_build_call (built_in_decls[BUILT_IN_ALLOCA], 1, x);
                  tmp = create_tmp_var_raw (ptr_type_node, NULL);
                  gimple_add_tmp_var (tmp);
                  gimple_call_set_lhs (stmt, tmp);

                  gimple_seq_add_stmt (ilist, stmt);

                  x = fold_convert_loc (clause_loc, TREE_TYPE (ptr), tmp);
                  gimplify_assign (ptr, x, ilist);
                }
            }
          else if (is_reference (var))
            {
              /* For references that are being privatized for Fortran,
                 allocate new backing storage for the new pointer
                 variable.  This allows us to avoid changing all the
                 code that expects a pointer to something that expects
                 a direct variable.  Note that this doesn't apply to
                 C++, since reference types are disallowed in data
                 sharing clauses there, except for NRV optimized
                 return values.  */
              if (pass == 0)
                continue;

              x = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (new_var)));
              if (c_kind == OMP_CLAUSE_FIRSTPRIVATE && is_task_ctx (ctx))
                {
                  x = build_receiver_ref (var, false, ctx);
                  x = build_fold_addr_expr_loc (clause_loc, x);
                }
              else if (TREE_CONSTANT (x))
                {
                  const char *name = NULL;
                  if (DECL_NAME (var))
                    name = IDENTIFIER_POINTER (DECL_NAME (new_var));

                  x = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (new_var)),
                                          name);
                  gimple_add_tmp_var (x);
                  TREE_ADDRESSABLE (x) = 1;
                  x = build_fold_addr_expr_loc (clause_loc, x);
                }
              else
                {
                  x = build_call_expr_loc (clause_loc,
                                       built_in_decls[BUILT_IN_ALLOCA], 1, x);
                }

              x = fold_convert_loc (clause_loc, TREE_TYPE (new_var), x);
              gimplify_assign (new_var, x, ilist);

              new_var = build_fold_indirect_ref_loc (clause_loc, new_var);
            }
          else if (c_kind == OMP_CLAUSE_REDUCTION
                   && OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
            {
              if (pass == 0)
                continue;
            }
          else if (pass != 0)
            continue;

          switch (OMP_CLAUSE_CODE (c))
            {
            case OMP_CLAUSE_SHARED:
              /* Shared global vars are just accessed directly.  */
              if (is_global_var (new_var))
                break;
              /* Set up the DECL_VALUE_EXPR for shared variables now.  This
                 needs to be delayed until after fixup_child_record_type so
                 that we get the correct type during the dereference.  */
              by_ref = use_pointer_for_field (var, ctx);
              x = build_receiver_ref (var, by_ref, ctx);
              SET_DECL_VALUE_EXPR (new_var, x);
              DECL_HAS_VALUE_EXPR_P (new_var) = 1;

              /* ??? If VAR is not passed by reference, and the variable
                 hasn't been initialized yet, then we'll get a warning for
                 the store into the omp_data_s structure.  Ideally, we'd be
                 able to notice this and not store anything at all, but 
                 we're generating code too early.  Suppress the warning.  */
              if (!by_ref)
                TREE_NO_WARNING (var) = 1;
              break;

            case OMP_CLAUSE_LASTPRIVATE:
              if (OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE (c))
                break;
              /* FALLTHRU */

            case OMP_CLAUSE_PRIVATE:
              if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_PRIVATE)
                x = build_outer_var_ref (var, ctx);
              else if (OMP_CLAUSE_PRIVATE_OUTER_REF (c))
                {
                  if (is_task_ctx (ctx))
                    x = build_receiver_ref (var, false, ctx);
                  else
                    x = build_outer_var_ref (var, ctx);
                }
              else
                x = NULL;
              x = lang_hooks.decls.omp_clause_default_ctor (c, new_var, x);
              if (x)
                gimplify_and_add (x, ilist);
              /* FALLTHRU */

            do_dtor:
              x = lang_hooks.decls.omp_clause_dtor (c, new_var);
              if (x)
                {
                  gimple_seq tseq = NULL;

                  dtor = x;
                  gimplify_stmt (&dtor, &tseq);
                  gsi_insert_seq_before (&diter, tseq, GSI_SAME_STMT);
                }
              break;

            case OMP_CLAUSE_FIRSTPRIVATE:
              if (is_task_ctx (ctx))
                {
                  if (is_reference (var) || is_variable_sized (var))
                    goto do_dtor;
                  else if (is_global_var (maybe_lookup_decl_in_outer_ctx (var,
                                                                          ctx))
                           || use_pointer_for_field (var, NULL))
                    {
                      x = build_receiver_ref (var, false, ctx);
                      SET_DECL_VALUE_EXPR (new_var, x);
                      DECL_HAS_VALUE_EXPR_P (new_var) = 1;
                      goto do_dtor;
                    }
                }
              x = build_outer_var_ref (var, ctx);
              x = lang_hooks.decls.omp_clause_copy_ctor (c, new_var, x);
              gimplify_and_add (x, ilist);
              goto do_dtor;
              break;

            case OMP_CLAUSE_COPYIN:
              by_ref = use_pointer_for_field (var, NULL);
              x = build_receiver_ref (var, by_ref, ctx);
              x = lang_hooks.decls.omp_clause_assign_op (c, new_var, x);
              append_to_statement_list (x, &copyin_seq);
              copyin_by_ref |= by_ref;
              break;

            case OMP_CLAUSE_REDUCTION:
              if (OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
                {
                  tree placeholder = OMP_CLAUSE_REDUCTION_PLACEHOLDER (c);
                  x = build_outer_var_ref (var, ctx);

                  if (is_reference (var))
                    x = build_fold_addr_expr_loc (clause_loc, x);
                  SET_DECL_VALUE_EXPR (placeholder, x);
                  DECL_HAS_VALUE_EXPR_P (placeholder) = 1;
                  lower_omp (OMP_CLAUSE_REDUCTION_GIMPLE_INIT (c), ctx);
                  gimple_seq_add_seq (ilist,
                                      OMP_CLAUSE_REDUCTION_GIMPLE_INIT (c));
                  OMP_CLAUSE_REDUCTION_GIMPLE_INIT (c) = NULL;
                  DECL_HAS_VALUE_EXPR_P (placeholder) = 0;
                }
              else
                {
                  x = omp_reduction_init (c, TREE_TYPE (new_var));
                  gcc_assert (TREE_CODE (TREE_TYPE (new_var)) != ARRAY_TYPE);
                  gimplify_assign (new_var, x, ilist);
                }
              break;

            default:
              gcc_unreachable ();
            }
        }
    }

  /* The copyin sequence is not to be executed by the main thread, since
     that would result in self-copies.  Perhaps not visible to scalars,
     but it certainly is to C++ operator=.  */
  if (copyin_seq)
    {
      x = build_call_expr (built_in_decls[BUILT_IN_OMP_GET_THREAD_NUM], 0);
      x = build2 (NE_EXPR, boolean_type_node, x,
                  build_int_cst (TREE_TYPE (x), 0));
      x = build3 (COND_EXPR, void_type_node, x, copyin_seq, NULL);
      gimplify_and_add (x, ilist);
    }

  /* If any copyin variable is passed by reference, we must ensure the
     master thread doesn't modify it before it is copied over in all
     threads.  Similarly for variables in both firstprivate and
     lastprivate clauses we need to ensure the lastprivate copying
     happens after firstprivate copying in all threads.  */
  if (copyin_by_ref || lastprivate_firstprivate)
    gimplify_and_add (build_omp_barrier (), ilist);
}


/* Generate code to implement the LASTPRIVATE clauses.  This is used for
   both parallel and workshare constructs.  PREDICATE may be NULL if it's
   always true.   */

static void
lower_lastprivate_clauses (tree clauses, tree predicate, gimple_seq *stmt_list,
                            omp_context *ctx)
{
  tree x, c, label = NULL;
  bool par_clauses = false;

  /* Early exit if there are no lastprivate clauses.  */
  clauses = find_omp_clause (clauses, OMP_CLAUSE_LASTPRIVATE);
  if (clauses == NULL)
    {
      /* If this was a workshare clause, see if it had been combined
         with its parallel.  In that case, look for the clauses on the
         parallel statement itself.  */
      if (is_parallel_ctx (ctx))
        return;

      ctx = ctx->outer;
      if (ctx == NULL || !is_parallel_ctx (ctx))
        return;

      clauses = find_omp_clause (gimple_omp_parallel_clauses (ctx->stmt),
                                 OMP_CLAUSE_LASTPRIVATE);
      if (clauses == NULL)
        return;
      par_clauses = true;
    }

  if (predicate)
    {
      gimple stmt;
      tree label_true, arm1, arm2;

      label = create_artificial_label (UNKNOWN_LOCATION);
      label_true = create_artificial_label (UNKNOWN_LOCATION);
      arm1 = TREE_OPERAND (predicate, 0);
      arm2 = TREE_OPERAND (predicate, 1);
      gimplify_expr (&arm1, stmt_list, NULL, is_gimple_val, fb_rvalue);
      gimplify_expr (&arm2, stmt_list, NULL, is_gimple_val, fb_rvalue);
      stmt = gimple_build_cond (TREE_CODE (predicate), arm1, arm2,
                                label_true, label);
      gimple_seq_add_stmt (stmt_list, stmt);
      gimple_seq_add_stmt (stmt_list, gimple_build_label (label_true));
    }

  for (c = clauses; c ;)
    {
      tree var, new_var;
      location_t clause_loc = OMP_CLAUSE_LOCATION (c);

      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LASTPRIVATE)
        {
          var = OMP_CLAUSE_DECL (c);
          new_var = lookup_decl (var, ctx);

          if (OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c))
            {
              lower_omp (OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c), ctx);
              gimple_seq_add_seq (stmt_list,
                                  OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c));
            }
          OMP_CLAUSE_LASTPRIVATE_GIMPLE_SEQ (c) = NULL;

          x = build_outer_var_ref (var, ctx);
          if (is_reference (var))
            new_var = build_fold_indirect_ref_loc (clause_loc, new_var);
          x = lang_hooks.decls.omp_clause_assign_op (c, x, new_var);
          gimplify_and_add (x, stmt_list);
        }
      c = OMP_CLAUSE_CHAIN (c);
      if (c == NULL && !par_clauses)
        {
          /* If this was a workshare clause, see if it had been combined
             with its parallel.  In that case, continue looking for the
             clauses also on the parallel statement itself.  */
          if (is_parallel_ctx (ctx))
            break;

          ctx = ctx->outer;
          if (ctx == NULL || !is_parallel_ctx (ctx))
            break;

          c = find_omp_clause (gimple_omp_parallel_clauses (ctx->stmt),
                               OMP_CLAUSE_LASTPRIVATE);
          par_clauses = true;
        }
    }

  if (label)
    gimple_seq_add_stmt (stmt_list, gimple_build_label (label));
}


/* Generate code to implement the REDUCTION clauses.  */

static void
lower_reduction_clauses (tree clauses, gimple_seq *stmt_seqp, omp_context *ctx)
{
  gimple_seq sub_seq = NULL;
  gimple stmt;
  tree x, c;
  int count = 0;

  /* First see if there is exactly one reduction clause.  Use OMP_ATOMIC
     update in that case, otherwise use a lock.  */
  for (c = clauses; c && count < 2; c = OMP_CLAUSE_CHAIN (c))
    if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION)
      {
        if (OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
          {
            /* Never use OMP_ATOMIC for array reductions.  */
            count = -1;
            break;
          }
        count++;
      }

  if (count == 0)
    return;

  for (c = clauses; c ; c = OMP_CLAUSE_CHAIN (c))
    {
      tree var, ref, new_var;
      enum tree_code code;
      location_t clause_loc = OMP_CLAUSE_LOCATION (c);

      if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_REDUCTION)
        continue;

      var = OMP_CLAUSE_DECL (c);
      new_var = lookup_decl (var, ctx);
      if (is_reference (var))
        new_var = build_fold_indirect_ref_loc (clause_loc, new_var);
      ref = build_outer_var_ref (var, ctx);
      code = OMP_CLAUSE_REDUCTION_CODE (c);

      /* reduction(-:var) sums up the partial results, so it acts
         identically to reduction(+:var).  */
      if (code == MINUS_EXPR)
        code = PLUS_EXPR;

      if (count == 1)
        {
          tree addr = build_fold_addr_expr_loc (clause_loc, ref);

          addr = save_expr (addr);
          ref = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (addr)), addr);
          x = fold_build2_loc (clause_loc, code, TREE_TYPE (ref), ref, new_var);
          x = build2 (OMP_ATOMIC, void_type_node, addr, x);
          gimplify_and_add (x, stmt_seqp);
          return;
        }

      if (OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
        {
          tree placeholder = OMP_CLAUSE_REDUCTION_PLACEHOLDER (c);

          if (is_reference (var))
            ref = build_fold_addr_expr_loc (clause_loc, ref);
          SET_DECL_VALUE_EXPR (placeholder, ref);
          DECL_HAS_VALUE_EXPR_P (placeholder) = 1;
          lower_omp (OMP_CLAUSE_REDUCTION_GIMPLE_MERGE (c), ctx);
          gimple_seq_add_seq (&sub_seq, OMP_CLAUSE_REDUCTION_GIMPLE_MERGE (c));
          OMP_CLAUSE_REDUCTION_GIMPLE_MERGE (c) = NULL;
          OMP_CLAUSE_REDUCTION_PLACEHOLDER (c) = NULL;
        }
      else
        {
          x = build2 (code, TREE_TYPE (ref), ref, new_var);
          ref = build_outer_var_ref (var, ctx);
          gimplify_assign (ref, x, &sub_seq);
        }
    }

  stmt = gimple_build_call (built_in_decls[BUILT_IN_GOMP_ATOMIC_START], 0);
  gimple_seq_add_stmt (stmt_seqp, stmt);

  gimple_seq_add_seq (stmt_seqp, sub_seq);

  stmt = gimple_build_call (built_in_decls[BUILT_IN_GOMP_ATOMIC_END], 0);
  gimple_seq_add_stmt (stmt_seqp, stmt);
}


/* Generate code to implement the COPYPRIVATE clauses.  */

static void
lower_copyprivate_clauses (tree clauses, gimple_seq *slist, gimple_seq *rlist,
                            omp_context *ctx)
{
  tree c;

  for (c = clauses; c ; c = OMP_CLAUSE_CHAIN (c))
    {
      tree var, ref, x;
      bool by_ref;
      location_t clause_loc = OMP_CLAUSE_LOCATION (c);

      if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_COPYPRIVATE)
        continue;

      var = OMP_CLAUSE_DECL (c);
      by_ref = use_pointer_for_field (var, NULL);

      ref = build_sender_ref (var, ctx);
      x = lookup_decl_in_outer_ctx (var, ctx);
      x = by_ref ? build_fold_addr_expr_loc (clause_loc, x) : x;
      gimplify_assign (ref, x, slist);

      ref = build_receiver_ref (var, by_ref, ctx);
      if (is_reference (var))
        {
          ref = build_fold_indirect_ref_loc (clause_loc, ref);
          var = build_fold_indirect_ref_loc (clause_loc, var);
        }
      x = lang_hooks.decls.omp_clause_assign_op (c, var, ref);
      gimplify_and_add (x, rlist);
    }
}


/* Generate code to implement the clauses, FIRSTPRIVATE, COPYIN, LASTPRIVATE,
   and REDUCTION from the sender (aka parent) side.  */

static void
lower_send_clauses (tree clauses, gimple_seq *ilist, gimple_seq *olist,
                    omp_context *ctx)
{
  tree c;

  for (c = clauses; c ; c = OMP_CLAUSE_CHAIN (c))
    {
      tree val, ref, x, var;
      bool by_ref, do_in = false, do_out = false;
      location_t clause_loc = OMP_CLAUSE_LOCATION (c);

      switch (OMP_CLAUSE_CODE (c))
        {
        case OMP_CLAUSE_PRIVATE:
          if (OMP_CLAUSE_PRIVATE_OUTER_REF (c))
            break;
          continue;
        case OMP_CLAUSE_FIRSTPRIVATE:
        case OMP_CLAUSE_COPYIN:
        case OMP_CLAUSE_LASTPRIVATE:
        case OMP_CLAUSE_REDUCTION:
          break;
        default:
          continue;
        }

      val = OMP_CLAUSE_DECL (c);
      var = lookup_decl_in_outer_ctx (val, ctx);

      if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_COPYIN
          && is_global_var (var))
        continue;
      if (is_variable_sized (val))
        continue;
      by_ref = use_pointer_for_field (val, NULL);

      switch (OMP_CLAUSE_CODE (c))
        {
        case OMP_CLAUSE_PRIVATE:
        case OMP_CLAUSE_FIRSTPRIVATE:
        case OMP_CLAUSE_COPYIN:
          do_in = true;
          break;

        case OMP_CLAUSE_LASTPRIVATE:
          if (by_ref || is_reference (val))
            {
              if (OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE (c))
                continue;
              do_in = true;
            }
          else
            {
              do_out = true;
              if (lang_hooks.decls.omp_private_outer_ref (val))
                do_in = true;
            }
          break;

        case OMP_CLAUSE_REDUCTION:
          do_in = true;
          do_out = !(by_ref || is_reference (val));
          break;

        default:
          gcc_unreachable ();
        }

      if (do_in)
        {
          ref = build_sender_ref (val, ctx);
          x = by_ref ? build_fold_addr_expr_loc (clause_loc, var) : var;
          gimplify_assign (ref, x, ilist);
          if (is_task_ctx (ctx))
            DECL_ABSTRACT_ORIGIN (TREE_OPERAND (ref, 1)) = NULL;
        }

      if (do_out)
        {
          ref = build_sender_ref (val, ctx);
          gimplify_assign (var, ref, olist);
        }
    }
}

/* Generate code to implement SHARED from the sender (aka parent)
   side.  This is trickier, since GIMPLE_OMP_PARALLEL_CLAUSES doesn't
   list things that got automatically shared.  */

static void
lower_send_shared_vars (gimple_seq *ilist, gimple_seq *olist, omp_context *ctx)
{
  tree var, ovar, nvar, f, x, record_type;

  if (ctx->record_type == NULL)
    return;

  record_type = ctx->srecord_type ? ctx->srecord_type : ctx->record_type;
  for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f))
    {
      ovar = DECL_ABSTRACT_ORIGIN (f);
      nvar = maybe_lookup_decl (ovar, ctx);
      if (!nvar || !DECL_HAS_VALUE_EXPR_P (nvar))
        continue;

      /* If CTX is a nested parallel directive.  Find the immediately
         enclosing parallel or workshare construct that contains a
         mapping for OVAR.  */
      var = lookup_decl_in_outer_ctx (ovar, ctx);

      if (use_pointer_for_field (ovar, ctx))
        {
          x = build_sender_ref (ovar, ctx);
          var = build_fold_addr_expr (var);
          gimplify_assign (x, var, ilist);
        }
      else
        {
          x = build_sender_ref (ovar, ctx);
          gimplify_assign (x, var, ilist);

          if (!TREE_READONLY (var)
              /* We don't need to receive a new reference to a result
                 or parm decl.  In fact we may not store to it as we will
                 invalidate any pending RSO and generate wrong gimple
                 during inlining.  */
              && !((TREE_CODE (var) == RESULT_DECL
                    || TREE_CODE (var) == PARM_DECL)
                   && DECL_BY_REFERENCE (var)))
            {
              x = build_sender_ref (ovar, ctx);
              gimplify_assign (var, x, olist);
            }
        }
    }
}


/* A convenience function to build an empty GIMPLE_COND with just the
   condition.  */

static gimple
gimple_build_cond_empty (tree cond)
{
  enum tree_code pred_code;
  tree lhs, rhs;

  gimple_cond_get_ops_from_tree (cond, &pred_code, &lhs, &rhs);
  return gimple_build_cond (pred_code, lhs, rhs, NULL_TREE, NULL_TREE);
}


/* Build the function calls to GOMP_parallel_start etc to actually 
   generate the parallel operation.  REGION is the parallel region
   being expanded.  BB is the block where to insert the code.  WS_ARGS
   will be set if this is a call to a combined parallel+workshare
   construct, it contains the list of additional arguments needed by
   the workshare construct.  */

static void
expand_parallel_call (struct omp_region *region, basic_block bb,
                      gimple entry_stmt, tree ws_args)
{
  tree t, t1, t2, val, cond, c, clauses;
  gimple_stmt_iterator gsi;
  gimple stmt;
  int start_ix;
  location_t clause_loc;

  clauses = gimple_omp_parallel_clauses (entry_stmt);

  /* Determine what flavor of GOMP_parallel_start we will be
     emitting.  */
  start_ix = BUILT_IN_GOMP_PARALLEL_START;
  if (is_combined_parallel (region))
    {
      switch (region->inner->type)
        {
        case GIMPLE_OMP_FOR:
          gcc_assert (region->inner->sched_kind != OMP_CLAUSE_SCHEDULE_AUTO);
          start_ix = BUILT_IN_GOMP_PARALLEL_LOOP_STATIC_START
                     + (region->inner->sched_kind
                        == OMP_CLAUSE_SCHEDULE_RUNTIME
                        ? 3 : region->inner->sched_kind);
          break;
        case GIMPLE_OMP_SECTIONS:
          start_ix = BUILT_IN_GOMP_PARALLEL_SECTIONS_START;
          break;
        default:
          gcc_unreachable ();
        }
    }

  /* By default, the value of NUM_THREADS is zero (selected at run time)
     and there is no conditional.  */
  cond = NULL_TREE;
  val = build_int_cst (unsigned_type_node, 0);

  c = find_omp_clause (clauses, OMP_CLAUSE_IF);
  if (c)
    cond = OMP_CLAUSE_IF_EXPR (c);

  c = find_omp_clause (clauses, OMP_CLAUSE_NUM_THREADS);
  if (c)
    {
      val = OMP_CLAUSE_NUM_THREADS_EXPR (c);
      clause_loc = OMP_CLAUSE_LOCATION (c);
    }
  else
    clause_loc = gimple_location (entry_stmt);

  /* Ensure 'val' is of the correct type.  */
  val = fold_convert_loc (clause_loc, unsigned_type_node, val);

  /* If we found the clause 'if (cond)', build either
     (cond != 0) or (cond ? val : 1u).  */
  if (cond)
    {
      gimple_stmt_iterator gsi;

      cond = gimple_boolify (cond);

      if (integer_zerop (val))
        val = fold_build2_loc (clause_loc,
                           EQ_EXPR, unsigned_type_node, cond,
                           build_int_cst (TREE_TYPE (cond), 0));
      else
        {
          basic_block cond_bb, then_bb, else_bb;
          edge e, e_then, e_else;
          tree tmp_then, tmp_else, tmp_join, tmp_var;

          tmp_var = create_tmp_var (TREE_TYPE (val), NULL);
          if (gimple_in_ssa_p (cfun))
            {
              tmp_then = make_ssa_name (tmp_var, NULL);
              tmp_else = make_ssa_name (tmp_var, NULL);
              tmp_join = make_ssa_name (tmp_var, NULL);
            }
          else
            {
              tmp_then = tmp_var;
              tmp_else = tmp_var;
              tmp_join = tmp_var;
            }

          e = split_block (bb, NULL);
          cond_bb = e->src;
          bb = e->dest;
          remove_edge (e);

          then_bb = create_empty_bb (cond_bb);
          else_bb = create_empty_bb (then_bb);
          set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
          set_immediate_dominator (CDI_DOMINATORS, else_bb, cond_bb);

          stmt = gimple_build_cond_empty (cond);
          gsi = gsi_start_bb (cond_bb);
          gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);

          gsi = gsi_start_bb (then_bb);
          stmt = gimple_build_assign (tmp_then, val);
          gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);

          gsi = gsi_start_bb (else_bb);
          stmt = gimple_build_assign
                   (tmp_else, build_int_cst (unsigned_type_node, 1));
          gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);

          make_edge (cond_bb, then_bb, EDGE_TRUE_VALUE);
          make_edge (cond_bb, else_bb, EDGE_FALSE_VALUE);
          e_then = make_edge (then_bb, bb, EDGE_FALLTHRU);
          e_else = make_edge (else_bb, bb, EDGE_FALLTHRU);

          if (gimple_in_ssa_p (cfun))
            {
              gimple phi = create_phi_node (tmp_join, bb);
              SSA_NAME_DEF_STMT (tmp_join) = phi;
              add_phi_arg (phi, tmp_then, e_then, UNKNOWN_LOCATION);
              add_phi_arg (phi, tmp_else, e_else, UNKNOWN_LOCATION);
            }

          val = tmp_join;
        }

      gsi = gsi_start_bb (bb);
      val = force_gimple_operand_gsi (&gsi, val, true, NULL_TREE,
                                      false, GSI_CONTINUE_LINKING);
    }

  gsi = gsi_last_bb (bb);
  t = gimple_omp_parallel_data_arg (entry_stmt);
  if (t == NULL)
    t1 = null_pointer_node;
  else
    t1 = build_fold_addr_expr (t);
  t2 = build_fold_addr_expr (gimple_omp_parallel_child_fn (entry_stmt));

  if (ws_args)
    {
      tree args = tree_cons (NULL, t2,
                             tree_cons (NULL, t1,
                                        tree_cons (NULL, val, ws_args)));
      t = build_function_call_expr (UNKNOWN_LOCATION,
                                    built_in_decls[start_ix], args);
    }
  else
    t = build_call_expr (built_in_decls[start_ix], 3, t2, t1, val);

  force_gimple_operand_gsi (&gsi, t, true, NULL_TREE,
                            false, GSI_CONTINUE_LINKING);

  t = gimple_omp_parallel_data_arg (entry_stmt);
  if (t == NULL)
    t = null_pointer_node;
  else
    t = build_fold_addr_expr (t);
  t = build_call_expr_loc (gimple_location (entry_stmt),
                           gimple_omp_parallel_child_fn (entry_stmt), 1, t);
  force_gimple_operand_gsi (&gsi, t, true, NULL_TREE,
                            false, GSI_CONTINUE_LINKING);

  t = build_call_expr_loc (gimple_location (entry_stmt),
                           built_in_decls[BUILT_IN_GOMP_PARALLEL_END], 0);
  force_gimple_operand_gsi (&gsi, t, true, NULL_TREE,
                            false, GSI_CONTINUE_LINKING);
}


/* Build the function call to GOMP_task to actually
   generate the task operation.  BB is the block where to insert the code.  */

static void
expand_task_call (basic_block bb, gimple entry_stmt)
{
  tree t, t1, t2, t3, flags, cond, c, clauses;
  gimple_stmt_iterator gsi;
  location_t loc = gimple_location (entry_stmt);

  clauses = gimple_omp_task_clauses (entry_stmt);

  c = find_omp_clause (clauses, OMP_CLAUSE_IF);
  if (c)
    cond = gimple_boolify (OMP_CLAUSE_IF_EXPR (c));
  else
    cond = boolean_true_node;

  c = find_omp_clause (clauses, OMP_CLAUSE_UNTIED);
  flags = build_int_cst (unsigned_type_node, (c ? 1 : 0));

  gsi = gsi_last_bb (bb);
  t = gimple_omp_task_data_arg (entry_stmt);
  if (t == NULL)
    t2 = null_pointer_node;
  else
    t2 = build_fold_addr_expr_loc (loc, t);
  t1 = build_fold_addr_expr_loc (loc, gimple_omp_task_child_fn (entry_stmt));
  t = gimple_omp_task_copy_fn (entry_stmt);
  if (t == NULL)
    t3 = null_pointer_node;
  else
    t3 = build_fold_addr_expr_loc (loc, t);

  t = build_call_expr (built_in_decls[BUILT_IN_GOMP_TASK], 7, t1, t2, t3,
                       gimple_omp_task_arg_size (entry_stmt),
                       gimple_omp_task_arg_align (entry_stmt), cond, flags);

  force_gimple_operand_gsi (&gsi, t, true, NULL_TREE,
                            false, GSI_CONTINUE_LINKING);
}


/* If exceptions are enabled, wrap the statements in BODY in a MUST_NOT_THROW
   catch handler and return it.  This prevents programs from violating the
   structured block semantics with throws.  */

static gimple_seq
maybe_catch_exception (gimple_seq body)
{
  gimple f, t;

  if (!flag_exceptions)
    return body;

  if (lang_protect_cleanup_actions)
    t = lang_protect_cleanup_actions ();
  else
    t = gimple_build_call (built_in_decls[BUILT_IN_TRAP], 0);

  f = gimple_build_eh_filter (NULL, gimple_seq_alloc_with_stmt (t));
  gimple_eh_filter_set_must_not_throw (f, true);

  t = gimple_build_try (body, gimple_seq_alloc_with_stmt (f),
                        GIMPLE_TRY_CATCH);

 return gimple_seq_alloc_with_stmt (t);
}

/* Chain all the DECLs in LIST by their TREE_CHAIN fields.  */

static tree
list2chain (tree list)
{
  tree t;

  for (t = list; t; t = TREE_CHAIN (t))
    {
      tree var = TREE_VALUE (t);
      if (TREE_CHAIN (t))
        TREE_CHAIN (var) = TREE_VALUE (TREE_CHAIN (t));
      else
        TREE_CHAIN (var) = NULL_TREE;
    }

  return list ? TREE_VALUE (list) : NULL_TREE;
}


/* Remove barriers in REGION->EXIT's block.  Note that this is only
   valid for GIMPLE_OMP_PARALLEL regions.  Since the end of a parallel region
   is an implicit barrier, any workshare inside the GIMPLE_OMP_PARALLEL that
   left a barrier at the end of the GIMPLE_OMP_PARALLEL region can now be
   removed.  */

static void
remove_exit_barrier (struct omp_region *region)
{
  gimple_stmt_iterator gsi;
  basic_block exit_bb;
  edge_iterator ei;
  edge e;
  gimple stmt;
  int any_addressable_vars = -1;

  exit_bb = region->exit;

  /* If the parallel region doesn't return, we don't have REGION->EXIT
     block at all.  */
  if (! exit_bb)
    return;

  /* The last insn in the block will be the parallel's GIMPLE_OMP_RETURN.  The
     workshare's GIMPLE_OMP_RETURN will be in a preceding block.  The kinds of
     statements that can appear in between are extremely limited -- no
     memory operations at all.  Here, we allow nothing at all, so the
     only thing we allow to precede this GIMPLE_OMP_RETURN is a label.  */
  gsi = gsi_last_bb (exit_bb);
  gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_RETURN);
  gsi_prev (&gsi);
  if (!gsi_end_p (gsi) && gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL)
    return;

  FOR_EACH_EDGE (e, ei, exit_bb->preds)
    {
      gsi = gsi_last_bb (e->src);
      if (gsi_end_p (gsi))
        continue;
      stmt = gsi_stmt (gsi);
      if (gimple_code (stmt) == GIMPLE_OMP_RETURN
          && !gimple_omp_return_nowait_p (stmt))
        {
          /* OpenMP 3.0 tasks unfortunately prevent this optimization
             in many cases.  If there could be tasks queued, the barrier
             might be needed to let the tasks run before some local
             variable of the parallel that the task uses as shared
             runs out of scope.  The task can be spawned either
             from within current function (this would be easy to check)
             or from some function it calls and gets passed an address
             of such a variable.  */
          if (any_addressable_vars < 0)
            {
              gimple parallel_stmt = last_stmt (region->entry);
              tree child_fun = gimple_omp_parallel_child_fn (parallel_stmt);
              tree local_decls = DECL_STRUCT_FUNCTION (child_fun)->local_decls;
              tree block;

              any_addressable_vars = 0;
              for (; local_decls; local_decls = TREE_CHAIN (local_decls))
                if (TREE_ADDRESSABLE (TREE_VALUE (local_decls)))
                  {
                    any_addressable_vars = 1;
                    break;
                  }
              for (block = gimple_block (stmt);
                   !any_addressable_vars
                   && block
                   && TREE_CODE (block) == BLOCK;
                   block = BLOCK_SUPERCONTEXT (block))
                {
                  for (local_decls = BLOCK_VARS (block);
                       local_decls;
                       local_decls = TREE_CHAIN (local_decls))
                    if (TREE_ADDRESSABLE (local_decls))
                      {
                        any_addressable_vars = 1;
                        break;
                      }
                  if (block == gimple_block (parallel_stmt))
                    break;
                }
            }
          if (!any_addressable_vars)
            gimple_omp_return_set_nowait (stmt);
        }
    }
}

static void
remove_exit_barriers (struct omp_region *region)
{
  if (region->type == GIMPLE_OMP_PARALLEL)
    remove_exit_barrier (region);

  if (region->inner)
    {
      region = region->inner;
      remove_exit_barriers (region);
      while (region->next)
        {
          region = region->next;
          remove_exit_barriers (region);
        }
    }
}

/* Optimize omp_get_thread_num () and omp_get_num_threads ()
   calls.  These can't be declared as const functions, but
   within one parallel body they are constant, so they can be
   transformed there into __builtin_omp_get_{thread_num,num_threads} ()
   which are declared const.  Similarly for task body, except
   that in untied task omp_get_thread_num () can change at any task
   scheduling point.  */

static void
optimize_omp_library_calls (gimple entry_stmt)
{
  basic_block bb;
  gimple_stmt_iterator gsi;
  tree thr_num_id
    = DECL_ASSEMBLER_NAME (built_in_decls [BUILT_IN_OMP_GET_THREAD_NUM]);
  tree num_thr_id
    = DECL_ASSEMBLER_NAME (built_in_decls [BUILT_IN_OMP_GET_NUM_THREADS]);
  bool untied_task = (gimple_code (entry_stmt) == GIMPLE_OMP_TASK
                      && find_omp_clause (gimple_omp_task_clauses (entry_stmt),
                                          OMP_CLAUSE_UNTIED) != NULL);

  FOR_EACH_BB (bb)
    for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
      {
        gimple call = gsi_stmt (gsi);
        tree decl;

        if (is_gimple_call (call)
            && (decl = gimple_call_fndecl (call))
            && DECL_EXTERNAL (decl)
            && TREE_PUBLIC (decl)
            && DECL_INITIAL (decl) == NULL)
          {
            tree built_in;

            if (DECL_NAME (decl) == thr_num_id)
              {
                /* In #pragma omp task untied omp_get_thread_num () can change
                   during the execution of the task region.  */
                if (untied_task)
                  continue;
                built_in = built_in_decls [BUILT_IN_OMP_GET_THREAD_NUM];
              }
            else if (DECL_NAME (decl) == num_thr_id)
              built_in = built_in_decls [BUILT_IN_OMP_GET_NUM_THREADS];
            else
              continue;

            if (DECL_ASSEMBLER_NAME (decl) != DECL_ASSEMBLER_NAME (built_in)
                || gimple_call_num_args (call) != 0)
              continue;

            if (flag_exceptions && !TREE_NOTHROW (decl))
              continue;

            if (TREE_CODE (TREE_TYPE (decl)) != FUNCTION_TYPE
                || !types_compatible_p (TREE_TYPE (TREE_TYPE (decl)),
                                        TREE_TYPE (TREE_TYPE (built_in))))
              continue;

            gimple_call_set_fndecl (call, built_in);
          }
      }
}

/* Expand the OpenMP parallel or task directive starting at REGION.  */

static void
expand_omp_taskreg (struct omp_region *region)
{
  basic_block entry_bb, exit_bb, new_bb;
  struct function *child_cfun;
  tree child_fn, block, t, ws_args, *tp;
  tree save_current;
  gimple_stmt_iterator gsi;
  gimple entry_stmt, stmt;
  edge e;

  entry_stmt = last_stmt (region->entry);
  child_fn = gimple_omp_taskreg_child_fn (entry_stmt);
  child_cfun = DECL_STRUCT_FUNCTION (child_fn);
  /* If this function has been already instrumented, make sure
     the child function isn't instrumented again.  */
  child_cfun->after_tree_profile = cfun->after_tree_profile;

  entry_bb = region->entry;
  exit_bb = region->exit;

  if (is_combined_parallel (region))
    ws_args = region->ws_args;
  else
    ws_args = NULL_TREE;

  if (child_cfun->cfg)
    {
      /* Due to inlining, it may happen that we have already outlined
         the region, in which case all we need to do is make the
         sub-graph unreachable and emit the parallel call.  */
      edge entry_succ_e, exit_succ_e;
      gimple_stmt_iterator gsi;

      entry_succ_e = single_succ_edge (entry_bb);

      gsi = gsi_last_bb (entry_bb);
      gcc_assert (gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_PARALLEL
                  || gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_TASK);
      gsi_remove (&gsi, true);

      new_bb = entry_bb;
      if (exit_bb)
        {
          exit_succ_e = single_succ_edge (exit_bb);
          make_edge (new_bb, exit_succ_e->dest, EDGE_FALLTHRU);
        }
      remove_edge_and_dominated_blocks (entry_succ_e);
    }
  else
    {
      /* If the parallel region needs data sent from the parent
         function, then the very first statement (except possible
         tree profile counter updates) of the parallel body
         is a copy assignment .OMP_DATA_I = &.OMP_DATA_O.  Since
         &.OMP_DATA_O is passed as an argument to the child function,
         we need to replace it with the argument as seen by the child
         function.

         In most cases, this will end up being the identity assignment
         .OMP_DATA_I = .OMP_DATA_I.  However, if the parallel body had
         a function call that has been inlined, the original PARM_DECL
         .OMP_DATA_I may have been converted into a different local
         variable.  In which case, we need to keep the assignment.  */
      if (gimple_omp_taskreg_data_arg (entry_stmt))
        {
          basic_block entry_succ_bb = single_succ (entry_bb);
          gimple_stmt_iterator gsi;
          tree arg, narg;
          gimple parcopy_stmt = NULL;

          for (gsi = gsi_start_bb (entry_succ_bb); ; gsi_next (&gsi))
            {
              gimple stmt;

              gcc_assert (!gsi_end_p (gsi));
              stmt = gsi_stmt (gsi);
              if (gimple_code (stmt) != GIMPLE_ASSIGN)
                continue;

              if (gimple_num_ops (stmt) == 2)
                {
                  tree arg = gimple_assign_rhs1 (stmt);

                  /* We're ignore the subcode because we're
                     effectively doing a STRIP_NOPS.  */

                  if (TREE_CODE (arg) == ADDR_EXPR
                      && TREE_OPERAND (arg, 0)
                        == gimple_omp_taskreg_data_arg (entry_stmt))
                    {
                      parcopy_stmt = stmt;
                      break;
                    }
                }
            }

          gcc_assert (parcopy_stmt != NULL);
          arg = DECL_ARGUMENTS (child_fn);

          if (!gimple_in_ssa_p (cfun))
            {
              if (gimple_assign_lhs (parcopy_stmt) == arg)
                gsi_remove (&gsi, true);
              else
                {
                  /* ?? Is setting the subcode really necessary ??  */
                  gimple_omp_set_subcode (parcopy_stmt, TREE_CODE (arg));
                  gimple_assign_set_rhs1 (parcopy_stmt, arg);
                }
            }
          else
            {
              /* If we are in ssa form, we must load the value from the default
                 definition of the argument.  That should not be defined now,
                 since the argument is not used uninitialized.  */
              gcc_assert (gimple_default_def (cfun, arg) == NULL);
              narg = make_ssa_name (arg, gimple_build_nop ());
              set_default_def (arg, narg);
              /* ?? Is setting the subcode really necessary ??  */
              gimple_omp_set_subcode (parcopy_stmt, TREE_CODE (narg));
              gimple_assign_set_rhs1 (parcopy_stmt, narg);
              update_stmt (parcopy_stmt);
            }
        }

      /* Declare local variables needed in CHILD_CFUN.  */
      block = DECL_INITIAL (child_fn);
      BLOCK_VARS (block) = list2chain (child_cfun->local_decls);
      /* The gimplifier could record temporaries in parallel/task block
         rather than in containing function's local_decls chain,
         which would mean cgraph missed finalizing them.  Do it now.  */
      for (t = BLOCK_VARS (block); t; t = TREE_CHAIN (t))
        if (TREE_CODE (t) == VAR_DECL
            && TREE_STATIC (t)
            && !DECL_EXTERNAL (t))
          varpool_finalize_decl (t);
      DECL_SAVED_TREE (child_fn) = NULL;
      gimple_set_body (child_fn, bb_seq (single_succ (entry_bb)));
      TREE_USED (block) = 1;

      /* Reset DECL_CONTEXT on function arguments.  */
      for (t = DECL_ARGUMENTS (child_fn); t; t = TREE_CHAIN (t))
        DECL_CONTEXT (t) = child_fn;

      /* Split ENTRY_BB at GIMPLE_OMP_PARALLEL or GIMPLE_OMP_TASK,
         so that it can be moved to the child function.  */
      gsi = gsi_last_bb (entry_bb);
      stmt = gsi_stmt (gsi);
      gcc_assert (stmt && (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
                           || gimple_code (stmt) == GIMPLE_OMP_TASK));
      gsi_remove (&gsi, true);
      e = split_block (entry_bb, stmt);
      entry_bb = e->dest;
      single_succ_edge (entry_bb)->flags = EDGE_FALLTHRU;

      /* Convert GIMPLE_OMP_RETURN into a RETURN_EXPR.  */
      if (exit_bb)
        {
          gsi = gsi_last_bb (exit_bb);
          gcc_assert (!gsi_end_p (gsi)
                      && gimple_code (gsi_stmt (gsi)) == GIMPLE_OMP_RETURN);
          stmt = gimple_build_return (NULL);
          gsi_insert_after (&gsi, stmt, GSI_SAME_STMT);
          gsi_remove (&gsi, true);
        }

      /* Move the parallel region into CHILD_CFUN.  */
 
      if (gimple_in_ssa_p (cfun))
        {
          push_cfun (child_cfun);
          init_tree_ssa (child_cfun);
          init_ssa_operands ();
          cfun->gimple_df->in_ssa_p = true;
          pop_cfun ();
          block = NULL_TREE;
        }
      else
        block = gimple_block (entry_stmt);

      new_bb = move_sese_region_to_fn (child_cfun, entry_bb, exit_bb, block);
      if (exit_bb)
        single_succ_edge (new_bb)->flags = EDGE_FALLTHRU;

      /* Remove non-local VAR_DECLs from child_cfun->local_decls list.  */
      for (tp = &child_cfun->local_decls; *tp; )
        if (DECL_CONTEXT (TREE_VALUE (*tp)) != cfun->decl)
          tp = &TREE_CHAIN (*tp);
        else
          *tp = TREE_CHAIN (*tp);

      /* Inform the callgraph about the new function.  */
      DECL_STRUCT_FUNCTION (child_fn)->curr_properties
        = cfun->curr_properties;
      cgraph_add_new_function (child_fn, true);

      /* Fix the callgraph edges for child_cfun.  Those for cfun will be
         fixed in a following pass.  */
      push_cfun (child_cfun);
      save_current = current_function_decl;
      current_function_decl = child_fn;
      if (optimize)
        optimize_omp_library_calls (entry_stmt);
      rebuild_cgraph_edges ();

      /* Some EH regions might become dead, see PR34608.  If
         pass_cleanup_cfg isn't the first pass to happen with the
         new child, these dead EH edges might cause problems.
         Clean them up now.  */
      if (flag_exceptions)
        {
          basic_block bb;
          bool changed = false;

          FOR_EACH_BB (bb)
            changed |= gimple_purge_dead_eh_edges (bb);
          if (changed)
            cleanup_tree_cfg ();