gcc/omp-low.c

/* Lowering pass for OMP directives.  Converts OMP directives into explicit
   calls to the runtime library (libgomp), data marshalling to implement data
   sharing and copying clauses, offloading to accelerators, and more.

   Contributed by Diego Novillo <dnovillo@redhat.com>

   Copyright (C) 2005-2018 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 "backend.h"
#include "target.h"
#include "tree.h"
#include "gimple.h"
#include "tree-pass.h"
#include "ssa.h"
#include "cgraph.h"
#include "pretty-print.h"
#include "diagnostic-core.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "internal-fn.h"
#include "gimple-fold.h"
#include "gimplify.h"
#include "gimple-iterator.h"
#include "gimplify-me.h"
#include "gimple-walk.h"
#include "tree-iterator.h"
#include "tree-inline.h"
#include "langhooks.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
#include "splay-tree.h"
#include "omp-general.h"
#include "omp-low.h"
#include "omp-grid.h"
#include "gimple-low.h"
#include "symbol-summary.h"
#include "tree-nested.h"
#include "context.h"
#include "gomp-constants.h"
#include "gimple-pretty-print.h"
#include "hsa-common.h"
#include "stringpool.h"
#include "attribs.h"

/* Lowering of OMP 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 regions which are then moved to a new
   function, to be invoked by the thread library, or offloaded.  */

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

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;

  /* Label to which GOMP_cancel{,llation_point} and explicit and implicit
     barriers should jump to during omplower pass.  */
  tree cancel_label;

  /* The sibling GIMPLE_OMP_FOR simd with _simt_ clause or NULL
     otherwise.  */
  gimple *simt_stmt;

  /* 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;

  /* True if this construct can be cancelled.  */
  bool cancellable;
};

static splay_tree all_contexts;
static int taskreg_nesting_level;
static int target_nesting_level;
static bitmap task_shared_vars;
static vec<omp_context *> taskreg_contexts;

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: \
    case GIMPLE_TRANSACTION: \
      /* The sub-statements for these should be walked.  */ \
      *handled_ops_p = false; \
      break;

/* Return true if CTX corresponds to an oacc parallel region.  */

static bool
is_oacc_parallel (omp_context *ctx)
{
  enum gimple_code outer_type = gimple_code (ctx->stmt);
  return ((outer_type == GIMPLE_OMP_TARGET)
	  && (gimple_omp_target_kind (ctx->stmt)
	      == GF_OMP_TARGET_KIND_OACC_PARALLEL));
}

/* Return true if CTX corresponds to an oacc kernels region.  */

static bool
is_oacc_kernels (omp_context *ctx)
{
  enum gimple_code outer_type = gimple_code (ctx->stmt);
  return ((outer_type == GIMPLE_OMP_TARGET)
	  && (gimple_omp_target_kind (ctx->stmt)
	      == GF_OMP_TARGET_KIND_OACC_KERNELS));
}

/* If DECL is the artificial dummy VAR_DECL created for non-static
   data member privatization, return the underlying "this" parameter,
   otherwise return NULL.  */

tree
omp_member_access_dummy_var (tree decl)
{
  if (!VAR_P (decl)
      || !DECL_ARTIFICIAL (decl)
      || !DECL_IGNORED_P (decl)
      || !DECL_HAS_VALUE_EXPR_P (decl)
      || !lang_hooks.decls.omp_disregard_value_expr (decl, false))
    return NULL_TREE;

  tree v = DECL_VALUE_EXPR (decl);
  if (TREE_CODE (v) != COMPONENT_REF)
    return NULL_TREE;

  while (1)
    switch (TREE_CODE (v))
      {
      case COMPONENT_REF:
      case MEM_REF:
      case INDIRECT_REF:
      CASE_CONVERT:
      case POINTER_PLUS_EXPR:
	v = TREE_OPERAND (v, 0);
	continue;
      case PARM_DECL:
	if (DECL_CONTEXT (v) == current_function_decl
	    && DECL_ARTIFICIAL (v)
	    && TREE_CODE (TREE_TYPE (v)) == POINTER_TYPE)
	  return v;
	return NULL_TREE;
      default:
	return NULL_TREE;
      }
}

/* Helper for unshare_and_remap, called through walk_tree.  */

static tree
unshare_and_remap_1 (tree *tp, int *walk_subtrees, void *data)
{
  tree *pair = (tree *) data;
  if (*tp == pair[0])
    {
      *tp = unshare_expr (pair[1]);
      *walk_subtrees = 0;
    }
  else if (IS_TYPE_OR_DECL_P (*tp))
    *walk_subtrees = 0;
  return NULL_TREE;
}

/* Return unshare_expr (X) with all occurrences of FROM
   replaced with TO.  */

static tree
unshare_and_remap (tree x, tree from, tree to)
{
  tree pair[2] = { from, to };
  x = unshare_expr (x);
  walk_tree (&x, unshare_and_remap_1, pair, NULL);
  return x;
}

/* 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 *);

/* 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 taskloop.  */

static inline bool
is_taskloop_ctx (omp_context *ctx)
{
  return gimple_code (ctx->stmt) == GIMPLE_OMP_FOR
	 && gimple_omp_for_kind (ctx->stmt) == GF_OMP_FOR_KIND_TASKLOOP;
}


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

static inline bool
is_taskreg_ctx (omp_context *ctx)
{
  return is_parallel_ctx (ctx) || is_task_ctx (ctx);
}

/* 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)));
}

/* Lookup variables.  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 = ctx->cb.decl_map->get (var);
  return *n;
}

static inline tree
maybe_lookup_decl (const_tree var, omp_context *ctx)
{
  tree *n = ctx->cb.decl_map->get (const_cast<tree> (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 (splay_tree_key key, omp_context *ctx)
{
  splay_tree_node n;
  n = splay_tree_lookup (ctx->sfield_map
			 ? ctx->sfield_map : ctx->field_map, key);
  return (tree) n->value;
}

static inline tree
lookup_sfield (tree var, omp_context *ctx)
{
  return lookup_sfield ((splay_tree_key) var, ctx);
}

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

static inline tree
maybe_lookup_field (tree var, omp_context *ctx)
{
  return maybe_lookup_field ((splay_tree_key) var, ctx);
}

/* 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))
      || TYPE_ATOMIC (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)
    {
      gcc_assert (!is_gimple_omp_oacc (shared_ctx->stmt));

      /* ??? 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;

      /* lower_send_shared_vars only uses copy-in, but not copy-out
	 for these.  */
      if (TREE_READONLY (decl)
	  || ((TREE_CODE (decl) == RESULT_DECL
	       || TREE_CODE (decl) == PARM_DECL)
	      && DECL_BY_REFERENCE (decl)))
	return false;

      /* 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 (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)
		goto maybe_mark_addressable_and_ret;
	    }
	}

      /* For tasks avoid using copy-in/out.  As tasks can be
	 deferred or executed in different thread, when GOMP_task
	 returns, the task hasn't necessarily terminated.  */
      if (is_task_ctx (shared_ctx))
	{
	  tree outer;
	maybe_mark_addressable_and_ret:
	  outer = maybe_lookup_decl_in_outer_ctx (decl, shared_ctx);
	  if (is_gimple_reg (outer) && !omp_member_access_dummy_var (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;
}

/* 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;
  DECL_CHAIN (copy) = ctx->block_vars;
  /* If VAR is listed in task_shared_vars, it means it wasn't
     originally addressable and is just because task needs to take
     it's address.  But we don't need to take address of privatizations
     from that var.  */
  if (TREE_ADDRESSABLE (var)
      && task_shared_vars
      && bitmap_bit_p (task_shared_vars, DECL_UID (var)))
    TREE_ADDRESSABLE (copy) = 0;
  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 COMPONENT_REF and set TREE_THIS_VOLATILE and TREE_READONLY on it
   as appropriate.  */
static tree
omp_build_component_ref (tree obj, tree field)
{
  tree ret = build3 (COMPONENT_REF, TREE_TYPE (field), obj, field, NULL);
  if (TREE_THIS_VOLATILE (field))
    TREE_THIS_VOLATILE (ret) |= 1;
  if (TREE_READONLY (field))
    TREE_READONLY (ret) |= 1;
  return ret;
}

/* 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_simple_mem_ref (ctx->receiver_decl);
  TREE_THIS_NOTRAP (x) = 1;
  x = omp_build_component_ref (x, field);
  if (by_ref)
    {
      x = build_simple_mem_ref (x);
      TREE_THIS_NOTRAP (x) = 1;
    }

  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,
		     enum omp_clause_code code = OMP_CLAUSE_ERROR)
{
  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, code);
      x = build_simple_mem_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 ((gimple_code (ctx->stmt) == GIMPLE_OMP_FOR
	    && gimple_omp_for_kind (ctx->stmt) & GF_OMP_FOR_SIMD)
	   || (code == OMP_CLAUSE_PRIVATE
	       && (gimple_code (ctx->stmt) == GIMPLE_OMP_FOR
		   || gimple_code (ctx->stmt) == GIMPLE_OMP_SECTIONS
		   || gimple_code (ctx->stmt) == GIMPLE_OMP_SINGLE)))
    {
      /* #pragma omp simd isn't a worksharing construct, and can reference
	 even private vars in its linear etc. clauses.
	 Similarly for OMP_CLAUSE_PRIVATE with outer ref, that can refer
	 to private vars in all worksharing constructs.  */
      x = NULL_TREE;
      if (ctx->outer && is_taskreg_ctx (ctx))
	x = lookup_decl (var, ctx->outer);
      else if (ctx->outer)
	x = maybe_lookup_decl_in_outer_ctx (var, ctx);
      if (x == NULL_TREE)
	x = var;
    }
  else if (code == OMP_CLAUSE_LASTPRIVATE && is_taskloop_ctx (ctx))
    {
      gcc_assert (ctx->outer);
      splay_tree_node n
	= splay_tree_lookup (ctx->outer->field_map,
			     (splay_tree_key) &DECL_UID (var));
      if (n == NULL)
	{
	  if (is_global_var (maybe_lookup_decl_in_outer_ctx (var, ctx->outer)))
	    x = var;
	  else
	    x = lookup_decl (var, ctx->outer);
	}
      else
	{
	  tree field = (tree) n->value;
	  /* 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->outer);
	  if (x != NULL)
	    field = x;

	  x = build_simple_mem_ref (ctx->outer->receiver_decl);
	  x = omp_build_component_ref (x, field);
	  if (use_pointer_for_field (var, ctx->outer))
	    x = build_simple_mem_ref (x);
	}
    }
  else if (ctx->outer)
    {
      omp_context *outer = ctx->outer;
      if (gimple_code (outer->stmt) == GIMPLE_OMP_GRID_BODY)
	{
	  outer = outer->outer;
	  gcc_assert (outer
		      && gimple_code (outer->stmt) != GIMPLE_OMP_GRID_BODY);
	}
      x = lookup_decl (var, outer);
    }
  else if (omp_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 if (omp_member_access_dummy_var (var))
    x = var;
  else
    gcc_unreachable ();

  if (x == var)
    {
      tree t = omp_member_access_dummy_var (var);
      if (t)
	{
	  x = DECL_VALUE_EXPR (var);
	  tree o = maybe_lookup_decl_in_outer_ctx (t, ctx);
	  if (o != t)
	    x = unshare_and_remap (x, t, o);
	  else
	    x = unshare_expr (x);
	}
    }

  if (omp_is_reference (var))
    x = build_simple_mem_ref (x);

  return x;
}

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

static tree
build_sender_ref (splay_tree_key key, omp_context *ctx)
{
  tree field = lookup_sfield (key, ctx);
  return omp_build_component_ref (ctx->sender_decl, field);
}

static tree
build_sender_ref (tree var, omp_context *ctx)
{
  return build_sender_ref ((splay_tree_key) var, ctx);
}

/* Add a new field for VAR inside the structure CTX->SENDER_DECL.  If
   BASE_POINTERS_RESTRICT, declare the field with restrict.  */

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

  if ((mask & 8) != 0)
    {
      key = (splay_tree_key) &DECL_UID (var);
      gcc_checking_assert (key != (splay_tree_key) var);
    }
  gcc_assert ((mask & 1) == 0
	      || !splay_tree_lookup (ctx->field_map, key));
  gcc_assert ((mask & 2) == 0 || !ctx->sfield_map
	      || !splay_tree_lookup (ctx->sfield_map, key));
  gcc_assert ((mask & 3) == 3
	      || !is_gimple_omp_oacc (ctx->stmt));

  type = TREE_TYPE (var);
  /* Prevent redeclaring the var in the split-off function with a restrict
     pointer type.  Note that we only clear type itself, restrict qualifiers in
     the pointed-to type will be ignored by points-to analysis.  */
  if (POINTER_TYPE_P (type)
      && TYPE_RESTRICT (type))
    type = build_qualified_type (type, TYPE_QUALS (type) & ~TYPE_QUAL_RESTRICT);

  if (mask & 4)
    {
      gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
      type = build_pointer_type (build_pointer_type (type));
    }
  else if (by_ref)
    {
      type = build_pointer_type (type);
      if (base_pointers_restrict)
	type = build_qualified_type (type, TYPE_QUAL_RESTRICT);
    }
  else if ((mask & 3) == 1 && omp_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))
    {
      SET_DECL_ALIGN (field, DECL_ALIGN (var));
      DECL_USER_ALIGN (field) = DECL_USER_ALIGN (var);
      TREE_THIS_VOLATILE (field) = TREE_THIS_VOLATILE (var);
    }
  else
    SET_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;
	  SET_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 (t),
				   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, key, (splay_tree_value) field);
  if ((mask & 2) && ctx->sfield_map)
    splay_tree_insert (ctx->sfield_map, key, (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)
    {
      if (FORCED_LABEL (var) || DECL_NONLOCAL (var))
	return var;
      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;
}

/* 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::get (current_function_decl);
      gcc_checking_assert (ctx->cb.src_node);
      ctx->cb.dst_node = ctx->cb.src_node;
      ctx->cb.src_cfun = cfun;
      ctx->cb.copy_decl = omp_copy_decl;
      ctx->cb.eh_lp_nr = 0;
      ctx->cb.transform_call_graph_edges = CB_CGE_MOVE;
      ctx->depth = 1;
    }

  ctx->cb.decl_map = new hash_map<tree, tree>;

  return ctx;
}

static gimple_seq maybe_catch_exception (gimple_seq);

/* Finalize task copyfn.  */

static void
finalize_task_copyfn (gomp_task *task_stmt)
{
  struct function *child_cfun;
  tree child_fn;
  gimple_seq seq = NULL, new_seq;
  gbind *bind;

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

  child_cfun = DECL_STRUCT_FUNCTION (child_fn);
  DECL_STRUCT_FUNCTION (child_fn)->curr_properties = cfun->curr_properties;

  push_cfun (child_cfun);
  bind = gimplify_body (child_fn, false);
  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 = NULL;
      gimple_seq_add_stmt (&seq, bind);
    }
  gimple_set_body (child_fn, seq);
  pop_cfun ();

  /* Inform the callgraph about the new function.  */
  cgraph_node *node = cgraph_node::get_create (child_fn);
  node->parallelized_function = 1;
  cgraph_node::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;

  delete 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 = DECL_CHAIN (t))
	DECL_ABSTRACT_ORIGIN (t) = NULL;
    }
  if (ctx->srecord_type)
    {
      tree t;
      for (t = TYPE_FIELDS (ctx->srecord_type); t ; t = DECL_CHAIN (t))
	DECL_ABSTRACT_ORIGIN (t) = NULL;
    }

  if (is_task_ctx (ctx))
    finalize_task_copyfn (as_a <gomp_task *> (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;

  if (!ctx->receiver_decl)
    return;
  /* ??? 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 = DECL_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 = DECL_CHAIN (f))
	{
	  tree new_f = copy_node (f);
	  DECL_CONTEXT (new_f) = type;
	  TREE_TYPE (new_f) = remap_type (TREE_TYPE (f), &ctx->cb);
	  DECL_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);
    }

  /* In a target region we never modify any of the pointers in *.omp_data_i,
     so attempt to help the optimizers.  */
  if (is_gimple_omp_offloaded (ctx->stmt))
    type = build_qualified_type (type, TYPE_QUAL_CONST);

  TREE_TYPE (ctx->receiver_decl)
    = build_qualified_type (build_reference_type (type), TYPE_QUAL_RESTRICT);
}

/* Instantiate decls as necessary in CTX to satisfy the data sharing
   specified by CLAUSES.  If BASE_POINTERS_RESTRICT, install var field with
   restrict.  */

static void
scan_sharing_clauses (tree clauses, omp_context *ctx,
		      bool base_pointers_restrict = false)
{
  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:
	  decl = OMP_CLAUSE_DECL (c);
	  /* Ignore shared directives in teams construct.  */
	  if (gimple_code (ctx->stmt) == GIMPLE_OMP_TEAMS)
	    {
	      /* Global variables don't need to be copied,
		 the receiver side will use them directly.  */
	      tree odecl = maybe_lookup_decl_in_outer_ctx (decl, ctx);
	      if (is_global_var (odecl))
		break;
	      insert_decl_map (&ctx->cb, decl, odecl);
	      break;
	    }
	  gcc_assert (is_taskreg_ctx (ctx));
	  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;
	  if (OMP_CLAUSE_SHARED_FIRSTPRIVATE (c))
	    {
	      use_pointer_for_field (decl, ctx);
	      break;
	    }
	  by_ref = use_pointer_for_field (decl, NULL);
	  if ((! TREE_READONLY (decl) && !OMP_CLAUSE_SHARED_READONLY (c))
	      || TREE_ADDRESSABLE (decl)
	      || by_ref
	      || omp_is_reference (decl))
	    {
	      by_ref = use_pointer_for_field (decl, ctx);
	      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_REDUCTION:
	  decl = OMP_CLAUSE_DECL (c);
	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION
	      && TREE_CODE (decl) == MEM_REF)
	    {
	      tree t = TREE_OPERAND (decl, 0);
	      if (TREE_CODE (t) == POINTER_PLUS_EXPR)
		t = TREE_OPERAND (t, 0);
	      if (TREE_CODE (t) == INDIRECT_REF
		  || TREE_CODE (t) == ADDR_EXPR)
		t = TREE_OPERAND (t, 0);
	      install_var_local (t, ctx);
	      if (is_taskreg_ctx (ctx)
		  && !is_global_var (maybe_lookup_decl_in_outer_ctx (t, ctx))
		  && !is_variable_sized (t))
		{
		  by_ref = use_pointer_for_field (t, ctx);
		  install_var_field (t, by_ref, 3, ctx);
		}
	      break;
	    }
	  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_LINEAR:
	  decl = OMP_CLAUSE_DECL (c);
	do_private:
	  if ((OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FIRSTPRIVATE
	       || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_IS_DEVICE_PTR)
	      && is_gimple_omp_offloaded (ctx->stmt))
	    {
	      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FIRSTPRIVATE)
		install_var_field (decl, !omp_is_reference (decl), 3, ctx);
	      else if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
		install_var_field (decl, true, 3, ctx);
	      else
		install_var_field (decl, false, 3, ctx);
	    }
	  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 || omp_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_USE_DEVICE_PTR:
	  decl = OMP_CLAUSE_DECL (c);
	  if (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
	    install_var_field (decl, true, 3, ctx);
	  else
	    install_var_field (decl, false, 3, ctx);
	  if (DECL_SIZE (decl)
	      && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
	    {
	      tree decl2 = DECL_VALUE_EXPR (decl);
	      gcc_assert (TREE_CODE (decl2) == INDIRECT_REF);
	      decl2 = TREE_OPERAND (decl2, 0);
	      gcc_assert (DECL_P (decl2));
	      install_var_local (decl2, ctx);
	    }
	  install_var_local (decl, ctx);
	  break;

	case OMP_CLAUSE_IS_DEVICE_PTR:
	  decl = OMP_CLAUSE_DECL (c);
	  goto do_private;

	case OMP_CLAUSE__LOOPTEMP_:
	  gcc_assert (is_taskreg_ctx (ctx));
	  decl = OMP_CLAUSE_DECL (c);
	  install_var_field (decl, false, 3, ctx);
	  install_var_local (decl, ctx);
	  break;

	case OMP_CLAUSE_COPYPRIVATE:
	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_FINAL:
	case OMP_CLAUSE_IF:
	case OMP_CLAUSE_NUM_THREADS:
	case OMP_CLAUSE_NUM_TEAMS:
	case OMP_CLAUSE_THREAD_LIMIT:
	case OMP_CLAUSE_DEVICE:
	case OMP_CLAUSE_SCHEDULE:
	case OMP_CLAUSE_DIST_SCHEDULE:
	case OMP_CLAUSE_DEPEND:
	case OMP_CLAUSE_PRIORITY:
	case OMP_CLAUSE_GRAINSIZE:
	case OMP_CLAUSE_NUM_TASKS:
	case OMP_CLAUSE_NUM_GANGS:
	case OMP_CLAUSE_NUM_WORKERS:
	case OMP_CLAUSE_VECTOR_LENGTH:
	  if (ctx->outer)
	    scan_omp_op (&OMP_CLAUSE_OPERAND (c, 0), ctx->outer);
	  break;

	case OMP_CLAUSE_TO:
	case OMP_CLAUSE_FROM:
	case OMP_CLAUSE_MAP:
	  if (ctx->outer)
	    scan_omp_op (&OMP_CLAUSE_SIZE (c), ctx->outer);
	  decl = OMP_CLAUSE_DECL (c);
	  /* Global variables with "omp declare target" attribute
	     don't need to be copied, the receiver side will use them
	     directly.  However, global variables with "omp declare target link"
	     attribute need to be copied.  */
	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
	      && DECL_P (decl)
	      && ((OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_FIRSTPRIVATE_POINTER
		   && (OMP_CLAUSE_MAP_KIND (c)
		       != GOMP_MAP_FIRSTPRIVATE_REFERENCE))
		  || TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
	      && is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx))
	      && varpool_node::get_create (decl)->offloadable
	      && !lookup_attribute ("omp declare target link",
				    DECL_ATTRIBUTES (decl)))
	    break;
	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
	      && OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_POINTER)
	    {
	      /* Ignore GOMP_MAP_POINTER kind for arrays in regions that are
		 not offloaded; there is nothing to map for those.  */
	      if (!is_gimple_omp_offloaded (ctx->stmt)
		  && !POINTER_TYPE_P (TREE_TYPE (decl))
		  && !OMP_CLAUSE_MAP_ZERO_BIAS_ARRAY_SECTION (c))
		break;
	    }
	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
	      && (OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER
		  || (OMP_CLAUSE_MAP_KIND (c)
		      == GOMP_MAP_FIRSTPRIVATE_REFERENCE)))
	    {
	      if (TREE_CODE (decl) == COMPONENT_REF
		  || (TREE_CODE (decl) == INDIRECT_REF
		      && TREE_CODE (TREE_OPERAND (decl, 0)) == COMPONENT_REF
		      && (TREE_CODE (TREE_TYPE (TREE_OPERAND (decl, 0)))
			  == REFERENCE_TYPE)))
		break;
	      if (DECL_SIZE (decl)
		  && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
		{
		  tree decl2 = DECL_VALUE_EXPR (decl);
		  gcc_assert (TREE_CODE (decl2) == INDIRECT_REF);
		  decl2 = TREE_OPERAND (decl2, 0);
		  gcc_assert (DECL_P (decl2));
		  install_var_local (decl2, ctx);
		}
	      install_var_local (decl, ctx);
	      break;
	    }
	  if (DECL_P (decl))
	    {
	      if (DECL_SIZE (decl)
		  && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
		{
		  tree decl2 = DECL_VALUE_EXPR (decl);
		  gcc_assert (TREE_CODE (decl2) == INDIRECT_REF);
		  decl2 = TREE_OPERAND (decl2, 0);
		  gcc_assert (DECL_P (decl2));
		  install_var_field (decl2, true, 3, ctx);
		  install_var_local (decl2, ctx);
		  install_var_local (decl, ctx);
		}
	      else
		{
		  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
		      && OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_POINTER
		      && !OMP_CLAUSE_MAP_ZERO_BIAS_ARRAY_SECTION (c)
		      && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
		    install_var_field (decl, true, 7, ctx);
		  else
		    install_var_field (decl, true, 3, ctx,
				       base_pointers_restrict);
		  if (is_gimple_omp_offloaded (ctx->stmt)
		      && !OMP_CLAUSE_MAP_IN_REDUCTION (c))
		    install_var_local (decl, ctx);
		}
	    }
	  else
	    {
	      tree base = get_base_address (decl);
	      tree nc = OMP_CLAUSE_CHAIN (c);
	      if (DECL_P (base)
		  && nc != NULL_TREE
		  && OMP_CLAUSE_CODE (nc) == OMP_CLAUSE_MAP
		  && OMP_CLAUSE_DECL (nc) == base
		  && OMP_CLAUSE_MAP_KIND (nc) == GOMP_MAP_POINTER
		  && integer_zerop (OMP_CLAUSE_SIZE (nc)))
		{
		  OMP_CLAUSE_MAP_ZERO_BIAS_ARRAY_SECTION (c) = 1;
		  OMP_CLAUSE_MAP_ZERO_BIAS_ARRAY_SECTION (nc) = 1;
		}
	      else
		{
		  if (ctx->outer)
		    {
		      scan_omp_op (&OMP_CLAUSE_DECL (c), ctx->outer);
		      decl = OMP_CLAUSE_DECL (c);
		    }
		  gcc_assert (!splay_tree_lookup (ctx->field_map,
						  (splay_tree_key) decl));
		  tree field
		    = build_decl (OMP_CLAUSE_LOCATION (c),
				  FIELD_DECL, NULL_TREE, ptr_type_node);
		  SET_DECL_ALIGN (field, TYPE_ALIGN (ptr_type_node));
		  insert_field_into_struct (ctx->record_type, field);
		  splay_tree_insert (ctx->field_map, (splay_tree_key) decl,
				     (splay_tree_value) field);
		}
	    }
	  break;

	case OMP_CLAUSE__GRIDDIM_:
	  if (ctx->outer)
	    {
	      scan_omp_op (&OMP_CLAUSE__GRIDDIM__SIZE (c), ctx->outer);
	      scan_omp_op (&OMP_CLAUSE__GRIDDIM__GROUP (c), ctx->outer);
	    }
	  break;

	case OMP_CLAUSE_NOWAIT:
	case OMP_CLAUSE_ORDERED:
	case OMP_CLAUSE_COLLAPSE:
	case OMP_CLAUSE_UNTIED:
	case OMP_CLAUSE_MERGEABLE:
	case OMP_CLAUSE_PROC_BIND:
	case OMP_CLAUSE_SAFELEN:
	case OMP_CLAUSE_SIMDLEN:
	case OMP_CLAUSE_THREADS:
	case OMP_CLAUSE_SIMD:
	case OMP_CLAUSE_NOGROUP:
	case OMP_CLAUSE_DEFAULTMAP:
	case OMP_CLAUSE_ASYNC:
	case OMP_CLAUSE_WAIT:
	case OMP_CLAUSE_GANG:
	case OMP_CLAUSE_WORKER:
	case OMP_CLAUSE_VECTOR:
	case OMP_CLAUSE_INDEPENDENT:
	case OMP_CLAUSE_AUTO:
	case OMP_CLAUSE_SEQ:
	case OMP_CLAUSE_TILE:
	case OMP_CLAUSE__SIMT_:
	case OMP_CLAUSE_DEFAULT:
	  break;

	case OMP_CLAUSE_ALIGNED:
	  decl = OMP_CLAUSE_DECL (c);
	  if (is_global_var (decl)
	      && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
	    install_var_local (decl, ctx);
	  break;

	case OMP_CLAUSE__CACHE_:
	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_FIRSTPRIVATE:
	case OMP_CLAUSE_PRIVATE:
	case OMP_CLAUSE_LINEAR:
	case OMP_CLAUSE_IS_DEVICE_PTR:
	  decl = OMP_CLAUSE_DECL (c);
	  if (is_variable_sized (decl))
	    {
	      if ((OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FIRSTPRIVATE
		   || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_IS_DEVICE_PTR)
		  && is_gimple_omp_offloaded (ctx->stmt))
		{
		  tree decl2 = DECL_VALUE_EXPR (decl);
		  gcc_assert (TREE_CODE (decl2) == INDIRECT_REF);
		  decl2 = TREE_OPERAND (decl2, 0);
		  gcc_assert (DECL_P (decl2));
		  install_var_local (decl2, ctx);
		  fixup_remapped_decl (decl2, ctx, false);
		}
	      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_LINEAR
	      && OMP_CLAUSE_LINEAR_GIMPLE_SEQ (c))
	    scan_array_reductions = true;
	  break;

	case OMP_CLAUSE_REDUCTION:
	  decl = OMP_CLAUSE_DECL (c);
	  if (TREE_CODE (decl) != MEM_REF)
	    {
	      if (is_variable_sized (decl))
		install_var_local (decl, ctx);
	      fixup_remapped_decl (decl, ctx, false);
	    }
	  if (OMP_CLAUSE_REDUCTION_PLACEHOLDER (c))
	    scan_array_reductions = true;
	  break;

	case OMP_CLAUSE_SHARED:
	  /* Ignore shared directives in teams construct.  */
	  if (gimple_code (ctx->stmt) == GIMPLE_OMP_TEAMS)
	    break;
	  decl = OMP_CLAUSE_DECL (c);
	  if (is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx)))
	    break;
	  if (OMP_CLAUSE_SHARED_FIRSTPRIVATE (c))
	    {
	      if (is_global_var (maybe_lookup_decl_in_outer_ctx (decl,
								 ctx->outer)))
		break;
	      bool by_ref = use_pointer_for_field (decl, ctx);
	      install_var_field (decl, by_ref, 11, ctx);
	      break;
	    }
	  fixup_remapped_decl (decl, ctx, false);
	  break;

	case OMP_CLAUSE_MAP:
	  if (!is_gimple_omp_offloaded (ctx->stmt))
	    break;
	  decl = OMP_CLAUSE_DECL (c);
	  if (DECL_P (decl)
	      && ((OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_FIRSTPRIVATE_POINTER
		   && (OMP_CLAUSE_MAP_KIND (c)
		       != GOMP_MAP_FIRSTPRIVATE_REFERENCE))
		  || TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
	      && is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx))
	      && varpool_node::get_create (decl)->offloadable)
	    break;
	  if (DECL_P (decl))
	    {
	      if ((OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_POINTER
		   || OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER)
		  && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
		  && !COMPLETE_TYPE_P (TREE_TYPE (decl)))
		{
		  tree new_decl = lookup_decl (decl, ctx);
		  TREE_TYPE (new_decl)
		    = remap_type (TREE_TYPE (decl), &ctx->cb);
		}
	      else if (DECL_SIZE (decl)
		       && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
		{
		  tree decl2 = DECL_VALUE_EXPR (decl);
		  gcc_assert (TREE_CODE (decl2) == INDIRECT_REF);
		  decl2 = TREE_OPERAND (decl2, 0);
		  gcc_assert (DECL_P (decl2));
		  fixup_remapped_decl (decl2, ctx, false);
		  fixup_remapped_decl (decl, ctx, true);
		}
	      else
		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_NUM_TEAMS:
	case OMP_CLAUSE_THREAD_LIMIT:
	case OMP_CLAUSE_DEVICE:
	case OMP_CLAUSE_SCHEDULE:
	case OMP_CLAUSE_DIST_SCHEDULE:
	case OMP_CLAUSE_NOWAIT:
	case OMP_CLAUSE_ORDERED:
	case OMP_CLAUSE_COLLAPSE:
	case OMP_CLAUSE_UNTIED:
	case OMP_CLAUSE_FINAL:
	case OMP_CLAUSE_MERGEABLE:
	case OMP_CLAUSE_PROC_BIND:
	case OMP_CLAUSE_SAFELEN:
	case OMP_CLAUSE_SIMDLEN:
	case OMP_CLAUSE_ALIGNED:
	case OMP_CLAUSE_DEPEND:
	case OMP_CLAUSE__LOOPTEMP_:
	case OMP_CLAUSE_TO:
	case OMP_CLAUSE_FROM:
	case OMP_CLAUSE_PRIORITY:
	case OMP_CLAUSE_GRAINSIZE:
	case OMP_CLAUSE_NUM_TASKS:
	case OMP_CLAUSE_THREADS:
	case OMP_CLAUSE_SIMD:
	case OMP_CLAUSE_NOGROUP:
	case OMP_CLAUSE_DEFAULTMAP:
	case OMP_CLAUSE_USE_DEVICE_PTR:
	case OMP_CLAUSE_ASYNC:
	case OMP_CLAUSE_WAIT:
	case OMP_CLAUSE_NUM_GANGS:
	case OMP_CLAUSE_NUM_WORKERS:
	case OMP_CLAUSE_VECTOR_LENGTH:
	case OMP_CLAUSE_GANG:
	case OMP_CLAUSE_WORKER:
	case OMP_CLAUSE_VECTOR:
	case OMP_CLAUSE_INDEPENDENT:
	case OMP_CLAUSE_AUTO:
	case OMP_CLAUSE_SEQ:
	case OMP_CLAUSE_TILE:
	case OMP_CLAUSE__GRIDDIM_:
	case OMP_CLAUSE__SIMT_:
	  break;

	case OMP_CLAUSE__CACHE_:
	default:
	  gcc_unreachable ();
	}
    }

  gcc_checking_assert (!scan_array_reductions
		       || !is_gimple_omp_oacc (ctx->stmt));
  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);
	else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LINEAR
		 && OMP_CLAUSE_LINEAR_GIMPLE_SEQ (c))
	  scan_omp (&OMP_CLAUSE_LINEAR_GIMPLE_SEQ (c), ctx);
    }
}

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

static tree
create_omp_child_function_name (bool task_copy)
{
  return clone_function_name (current_function_decl,
			      task_copy ? "_omp_cpyfn" : "_omp_fn");
}

/* Return true if CTX may belong to offloaded code: either if current function
   is offloaded, or any enclosing context corresponds to a target region.  */

static bool
omp_maybe_offloaded_ctx (omp_context *ctx)
{
  if (cgraph_node::get (current_function_decl)->offloadable)
    return true;
  for (; ctx; ctx = ctx->outer)
    if (is_gimple_omp_offloaded (ctx->stmt))
      return true;
  return false;
}

/* 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);

  gcc_checking_assert (!is_gimple_omp_oacc (ctx->stmt)
		       || !task_copy);
  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);
  BLOCK_SUPERCONTEXT (DECL_INITIAL (decl)) = decl;
  DECL_ATTRIBUTES (decl) = DECL_ATTRIBUTES (current_function_decl);
  /* Remove omp declare simd attribute from the new attributes.  */
  if (tree a = lookup_attribute ("omp declare simd", DECL_ATTRIBUTES (decl)))
    {
      while (tree a2 = lookup_attribute ("omp declare simd", TREE_CHAIN (a)))
	a = a2;
      a = TREE_CHAIN (a);
      for (tree *p = &DECL_ATTRIBUTES (decl); *p != a;)
	if (is_attribute_p ("omp declare simd", get_attribute_name (*p)))
	  *p = TREE_CHAIN (*p);
	else
	  {
	    tree chain = TREE_CHAIN (*p);
	    *p = copy_node (*p);
	    p = &TREE_CHAIN (*p);
	    *p = chain;
	  }
    }
  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl)
    = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (current_function_decl);
  DECL_FUNCTION_SPECIFIC_TARGET (decl)
    = DECL_FUNCTION_SPECIFIC_TARGET (current_function_decl);
  DECL_FUNCTION_VERSIONED (decl)
    = DECL_FUNCTION_VERSIONED (current_function_decl);

  if (omp_maybe_offloaded_ctx (ctx))
    {
      cgraph_node::get_create (decl)->offloadable = 1;
      if (ENABLE_OFFLOADING)
	g->have_offload = true;
    }

  if (cgraph_node::get_create (decl)->offloadable
      && !lookup_attribute ("omp declare target",
                           DECL_ATTRIBUTES (current_function_decl)))
    {
      const char *target_attr = (is_gimple_omp_offloaded (ctx->stmt)
				 ? "omp target entrypoint"
				 : "omp declare target");
      DECL_ATTRIBUTES (decl)
	= tree_cons (get_identifier (target_attr),
		     NULL_TREE, DECL_ATTRIBUTES (decl));
    }

  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;

  tree data_name = get_identifier (".omp_data_i");
  t = build_decl (DECL_SOURCE_LOCATION (decl), PARM_DECL, data_name,
		  ptr_type_node);
  DECL_ARTIFICIAL (t) = 1;
  DECL_NAMELESS (t) = 1;
  DECL_ARG_TYPE (t) = ptr_type_node;
  DECL_CONTEXT (t) = current_function_decl;
  TREE_USED (t) = 1;
  TREE_READONLY (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_NAMELESS (t) = 1;
      DECL_ARG_TYPE (t) = ptr_type_node;
      DECL_CONTEXT (t) = current_function_decl;
      TREE_USED (t) = 1;
      TREE_ADDRESSABLE (t) = 1;
      DECL_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);
  init_tree_ssa (cfun);
  pop_cfun ();
}

/* Callback for walk_gimple_seq.  Check if combined parallel
   contains gimple_omp_for_combined_into_p OMP_FOR.  */

tree
omp_find_combined_for (gimple_stmt_iterator *gsi_p,
		       bool *handled_ops_p,
		       struct walk_stmt_info *wi)
{
  gimple *stmt = gsi_stmt (*gsi_p);

  *handled_ops_p = true;
  switch (gimple_code (stmt))
    {
    WALK_SUBSTMTS;

    case GIMPLE_OMP_FOR:
      if (gimple_omp_for_combined_into_p (stmt)
	  && gimple_omp_for_kind (stmt)
	     == *(const enum gf_mask *) (wi->info))
	{
	  wi->info = stmt;
	  return integer_zero_node;
	}
      break;
    default:
      break;
    }
  return NULL;
}

/* Add _LOOPTEMP_ clauses on OpenMP parallel or task.  */

static void
add_taskreg_looptemp_clauses (enum gf_mask msk, gimple *stmt,
			      omp_context *outer_ctx)
{
  struct walk_stmt_info wi;

  memset (&wi, 0, sizeof (wi));
  wi.val_only = true;
  wi.info = (void *) &msk;
  walk_gimple_seq (gimple_omp_body (stmt), omp_find_combined_for, NULL, &wi);
  if (wi.info != (void *) &msk)
    {
      gomp_for *for_stmt = as_a <gomp_for *> ((gimple *) wi.info);
      struct omp_for_data fd;
      omp_extract_for_data (for_stmt, &fd, NULL);
      /* We need two temporaries with fd.loop.v type (istart/iend)
	 and then (fd.collapse - 1) temporaries with the same
	 type for count2 ... countN-1 vars if not constant.  */
      size_t count = 2, i;
      tree type = fd.iter_type;
      if (fd.collapse > 1
	  && TREE_CODE (fd.loop.n2) != INTEGER_CST)
	{
	  count += fd.collapse - 1;
	  /* If there are lastprivate clauses on the inner
	     GIMPLE_OMP_FOR, add one more temporaries for the total number
	     of iterations (product of count1 ... countN-1).  */
	  if (omp_find_clause (gimple_omp_for_clauses (for_stmt),
			       OMP_CLAUSE_LASTPRIVATE))
	    count++;
	  else if (msk == GF_OMP_FOR_KIND_FOR
		   && omp_find_clause (gimple_omp_parallel_clauses (stmt),
				       OMP_CLAUSE_LASTPRIVATE))
	    count++;
	}
      for (i = 0; i < count; i++)
	{
	  tree temp = create_tmp_var (type);
	  tree c = build_omp_clause (UNKNOWN_LOCATION, OMP_CLAUSE__LOOPTEMP_);
	  insert_decl_map (&outer_ctx->cb, temp, temp);
	  OMP_CLAUSE_DECL (c) = temp;
	  OMP_CLAUSE_CHAIN (c) = gimple_omp_taskreg_clauses (stmt);
	  gimple_omp_taskreg_set_clauses (stmt, c);
	}
    }
}

/* Scan an OpenMP parallel directive.  */

static void
scan_omp_parallel (gimple_stmt_iterator *gsi, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name;
  gomp_parallel *stmt = as_a <gomp_parallel *> (gsi_stmt (*gsi));

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

  if (gimple_omp_parallel_combined_p (stmt))
    add_taskreg_looptemp_clauses (GF_OMP_FOR_KIND_FOR, stmt, outer_ctx);

  ctx = new_omp_context (stmt, outer_ctx);
  taskreg_contexts.safe_push (ctx);
  if (taskreg_nesting_level > 1)
    ctx->is_nested = true;
  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_data_s");
  name = build_decl (gimple_location (stmt),
		     TYPE_DECL, name, ctx->record_type);
  DECL_ARTIFICIAL (name) = 1;
  DECL_NAMELESS (name) = 1;
  TYPE_NAME (ctx->record_type) = name;
  TYPE_ARTIFICIAL (ctx->record_type) = 1;
  if (!gimple_omp_parallel_grid_phony (stmt))
    {
      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_ptr (stmt), ctx);

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

/* Scan an OpenMP task directive.  */

static void
scan_omp_task (gimple_stmt_iterator *gsi, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name, t;
  gomp_task *stmt = as_a <gomp_task *> (gsi_stmt (*gsi));

  /* Ignore task directives with empty bodies, unless they have depend
     clause.  */
  if (optimize > 0
      && empty_body_p (gimple_omp_body (stmt))
      && !omp_find_clause (gimple_omp_task_clauses (stmt), OMP_CLAUSE_DEPEND))
    {
      gsi_replace (gsi, gimple_build_nop (), false);
      return;
    }

  if (gimple_omp_task_taskloop_p (stmt))
    add_taskreg_looptemp_clauses (GF_OMP_FOR_KIND_TASKLOOP, stmt, outer_ctx);

  ctx = new_omp_context (stmt, outer_ctx);
  taskreg_contexts.safe_push (ctx);
  if (taskreg_nesting_level > 1)
    ctx->is_nested = true;
  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_data_s");
  name = build_decl (gimple_location (stmt),
		     TYPE_DECL, name, ctx->record_type);
  DECL_ARTIFICIAL (name) = 1;
  DECL_NAMELESS (name) = 1;
  TYPE_NAME (ctx->record_type) = name;
  TYPE_ARTIFICIAL (ctx->record_type) = 1;
  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);
      DECL_ARTIFICIAL (name) = 1;
      DECL_NAMELESS (name) = 1;
      TYPE_NAME (ctx->srecord_type) = name;
      TYPE_ARTIFICIAL (ctx->srecord_type) = 1;
      create_omp_child_function (ctx, true);
    }

  scan_omp (gimple_omp_body_ptr (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);
    }
}

/* Helper function for finish_taskreg_scan, called through walk_tree.
   If maybe_lookup_decl_in_outer_context returns non-NULL for some
   tree, replace it in the expression.  */

static tree
finish_taskreg_remap (tree *tp, int *walk_subtrees, void *data)
{
  if (VAR_P (*tp))
    {
      omp_context *ctx = (omp_context *) data;
      tree t = maybe_lookup_decl_in_outer_ctx (*tp, ctx);
      if (t != *tp)
	{
	  if (DECL_HAS_VALUE_EXPR_P (t))
	    t = unshare_expr (DECL_VALUE_EXPR (t));
	  *tp = t;
	}
      *walk_subtrees = 0;
    }
  else if (IS_TYPE_OR_DECL_P (*tp))
    *walk_subtrees = 0;
  return NULL_TREE;
}

/* If any decls have been made addressable during scan_omp,
   adjust their fields if needed, and layout record types
   of parallel/task constructs.  */

static void
finish_taskreg_scan (omp_context *ctx)
{
  if (ctx->record_type == NULL_TREE)
    return;

  /* If any task_shared_vars were needed, verify all
     OMP_CLAUSE_SHARED clauses on GIMPLE_OMP_{PARALLEL,TASK}
     statements if use_pointer_for_field hasn't changed
     because of that.  If it did, update field types now.  */
  if (task_shared_vars)
    {
      tree c;

      for (c = gimple_omp_taskreg_clauses (ctx->stmt);
	   c; c = OMP_CLAUSE_CHAIN (c))
	if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
	    && !OMP_CLAUSE_SHARED_FIRSTPRIVATE (c))
	  {
	    tree decl = OMP_CLAUSE_DECL (c);

	    /* 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)))
	      continue;
	    if (!bitmap_bit_p (task_shared_vars, DECL_UID (decl))
		|| !use_pointer_for_field (decl, ctx))
	      continue;
	    tree field = lookup_field (decl, ctx);
	    if (TREE_CODE (TREE_TYPE (field)) == POINTER_TYPE
		&& TREE_TYPE (TREE_TYPE (field)) == TREE_TYPE (decl))
	      continue;
	    TREE_TYPE (field) = build_pointer_type (TREE_TYPE (decl));
	    TREE_THIS_VOLATILE (field) = 0;
	    DECL_USER_ALIGN (field) = 0;
	    SET_DECL_ALIGN (field, TYPE_ALIGN (TREE_TYPE (field)));
	    if (TYPE_ALIGN (ctx->record_type) < DECL_ALIGN (field))
	      SET_TYPE_ALIGN (ctx->record_type, DECL_ALIGN (field));
	    if (ctx->srecord_type)
	      {
		tree sfield = lookup_sfield (decl, ctx);
		TREE_TYPE (sfield) = TREE_TYPE (field);
		TREE_THIS_VOLATILE (sfield) = 0;
		DECL_USER_ALIGN (sfield) = 0;
		SET_DECL_ALIGN (sfield, DECL_ALIGN (field));
		if (TYPE_ALIGN (ctx->srecord_type) < DECL_ALIGN (sfield))
		  SET_TYPE_ALIGN (ctx->srecord_type, DECL_ALIGN (sfield));
	      }
	  }
    }

  if (gimple_code (ctx->stmt) == GIMPLE_OMP_PARALLEL)
    {
      layout_type (ctx->record_type);
      fixup_child_record_type (ctx);
    }
  else
    {
      location_t loc = gimple_location (ctx->stmt);
      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 = &DECL_CHAIN (*p);
      *p = vla_fields;
      if (gimple_omp_task_taskloop_p (ctx->stmt))
	{
	  /* Move fields corresponding to first and second _looptemp_
	     clause first.  There are filled by GOMP_taskloop
	     and thus need to be in specific positions.  */
	  tree c1 = gimple_omp_task_clauses (ctx->stmt);
	  c1 = omp_find_clause (c1, OMP_CLAUSE__LOOPTEMP_);
	  tree c2 = omp_find_clause (OMP_CLAUSE_CHAIN (c1),
				     OMP_CLAUSE__LOOPTEMP_);
	  tree f1 = lookup_field (OMP_CLAUSE_DECL (c1), ctx);
	  tree f2 = lookup_field (OMP_CLAUSE_DECL (c2), ctx);
	  p = &TYPE_FIELDS (ctx->record_type);
	  while (*p)
	    if (*p == f1 || *p == f2)
	      *p = DECL_CHAIN (*p);
	    else
	      p = &DECL_CHAIN (*p);
	  DECL_CHAIN (f1) = f2;
	  DECL_CHAIN (f2) = TYPE_FIELDS (ctx->record_type);
	  TYPE_FIELDS (ctx->record_type) = f1;
	  if (ctx->srecord_type)
	    {
	      f1 = lookup_sfield (OMP_CLAUSE_DECL (c1), ctx);
	      f2 = lookup_sfield (OMP_CLAUSE_DECL (c2), ctx);
	      p = &TYPE_FIELDS (ctx->srecord_type);
	      while (*p)
		if (*p == f1 || *p == f2)
		  *p = DECL_CHAIN (*p);
		else
		  p = &DECL_CHAIN (*p);
	      DECL_CHAIN (f1) = f2;
	      DECL_CHAIN (f2) = TYPE_FIELDS (ctx->srecord_type);
	      TYPE_FIELDS (ctx->srecord_type) = f1;
	    }
	}
      layout_type (ctx->record_type);
      fixup_child_record_type (ctx);
      if (ctx->srecord_type)
	layout_type (ctx->srecord_type);
      tree t = fold_convert_loc (loc, long_integer_type_node,
				 TYPE_SIZE_UNIT (ctx->record_type));
      if (TREE_CODE (t) != INTEGER_CST)
	{
	  t = unshare_expr (t);
	  walk_tree (&t, finish_taskreg_remap, ctx, NULL);
	}
      gimple_omp_task_set_arg_size (ctx->stmt, t);
      t = build_int_cst (long_integer_type_node,
			 TYPE_ALIGN_UNIT (ctx->record_type));
      gimple_omp_task_set_arg_align (ctx->stmt, t);
    }
}

/* Find the enclosing offload context.  */

static omp_context *
enclosing_target_ctx (omp_context *ctx)
{
  for (; ctx; ctx = ctx->outer)
    if (gimple_code (ctx->stmt) == GIMPLE_OMP_TARGET)
      break;

  return ctx;
}

/* Return true if ctx is part of an oacc kernels region.  */

static bool
ctx_in_oacc_kernels_region (omp_context *ctx)
{
  for (;ctx != NULL; ctx = ctx->outer)
    {
      gimple *stmt = ctx->stmt;
      if (gimple_code (stmt) == GIMPLE_OMP_TARGET
	  && gimple_omp_target_kind (stmt) == GF_OMP_TARGET_KIND_OACC_KERNELS)
	return true;
    }

  return false;
}

/* Check the parallelism clauses inside a kernels regions.
   Until kernels handling moves to use the same loop indirection
   scheme as parallel, we need to do this checking early.  */

static unsigned
check_oacc_kernel_gwv (gomp_for *stmt, omp_context *ctx)
{
  bool checking = true;
  unsigned outer_mask = 0;
  unsigned this_mask = 0;
  bool has_seq = false, has_auto = false;

  if (ctx->outer)
    outer_mask = check_oacc_kernel_gwv (NULL,  ctx->outer);
  if (!stmt)
    {
      checking = false;
      if (gimple_code (ctx->stmt) != GIMPLE_OMP_FOR)
	return outer_mask;
      stmt = as_a <gomp_for *> (ctx->stmt);
    }

  for (tree c = gimple_omp_for_clauses (stmt); c; c = OMP_CLAUSE_CHAIN (c))
    {
      switch (OMP_CLAUSE_CODE (c))
	{
	case OMP_CLAUSE_GANG:
	  this_mask |= GOMP_DIM_MASK (GOMP_DIM_GANG);
	  break;
	case OMP_CLAUSE_WORKER:
	  this_mask |= GOMP_DIM_MASK (GOMP_DIM_WORKER);
	  break;
	case OMP_CLAUSE_VECTOR:
	  this_mask |= GOMP_DIM_MASK (GOMP_DIM_VECTOR);
	  break;
	case OMP_CLAUSE_SEQ:
	  has_seq = true;
	  break;
	case OMP_CLAUSE_AUTO:
	  has_auto = true;
	  break;
	default:
	  break;
	}
    }

  if (checking)
    {
      if (has_seq && (this_mask || has_auto))
	error_at (gimple_location (stmt), "%<seq%> overrides other"
		  " OpenACC loop specifiers");
      else if (has_auto && this_mask)
	error_at (gimple_location (stmt), "%<auto%> conflicts with other"
		  " OpenACC loop specifiers");

      if (this_mask & outer_mask)
	error_at (gimple_location (stmt), "inner loop uses same"
		  " OpenACC parallelism as containing loop");
    }

  return outer_mask | this_mask;
}

/* Scan a GIMPLE_OMP_FOR.  */

static omp_context *
scan_omp_for (gomp_for *stmt, omp_context *outer_ctx)
{
  omp_context *ctx;
  size_t i;
  tree clauses = gimple_omp_for_clauses (stmt);

  ctx = new_omp_context (stmt, outer_ctx);

  if (is_gimple_omp_oacc (stmt))
    {
      omp_context *tgt = enclosing_target_ctx (outer_ctx);

      if (!tgt || is_oacc_parallel (tgt))
	for (tree c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
	  {
	    char const *check = NULL;

	    switch (OMP_CLAUSE_CODE (c))
	      {
	      case OMP_CLAUSE_GANG:
		check = "gang";
		break;

	      case OMP_CLAUSE_WORKER:
		check = "worker";
		break;

	      case OMP_CLAUSE_VECTOR:
		check = "vector";
		break;

	      default:
		break;
	      }

	    if (check && OMP_CLAUSE_OPERAND (c, 0))
	      error_at (gimple_location (stmt),
			"argument not permitted on %qs clause in"
			" OpenACC %<parallel%>", check);
	  }

      if (tgt && is_oacc_kernels (tgt))
	{
	  /* Strip out reductions, as they are not  handled yet.  */
	  tree *prev_ptr = &clauses;

	  while (tree probe = *prev_ptr)
	    {
	      tree *next_ptr = &OMP_CLAUSE_CHAIN (probe);
	      
	      if (OMP_CLAUSE_CODE (probe) == OMP_CLAUSE_REDUCTION)
		*prev_ptr = *next_ptr;
	      else
		prev_ptr = next_ptr;
	    }

	  gimple_omp_for_set_clauses (stmt, clauses);
	  check_oacc_kernel_gwv (stmt, ctx);
	}
    }

  scan_sharing_clauses (clauses, ctx);

  scan_omp (gimple_omp_for_pre_body_ptr (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_ptr (stmt), ctx);
  return ctx;
}

/* Duplicate #pragma omp simd, one for SIMT, another one for SIMD.  */

static void
scan_omp_simd (gimple_stmt_iterator *gsi, gomp_for *stmt,
	       omp_context *outer_ctx)
{
  gbind *bind = gimple_build_bind (NULL, NULL, NULL);
  gsi_replace (gsi, bind, false);
  gimple_seq seq = NULL;
  gimple *g = gimple_build_call_internal (IFN_GOMP_USE_SIMT, 0);
  tree cond = create_tmp_var_raw (integer_type_node);
  DECL_CONTEXT (cond) = current_function_decl;
  DECL_SEEN_IN_BIND_EXPR_P (cond) = 1;
  gimple_bind_set_vars (bind, cond);
  gimple_call_set_lhs (g, cond);
  gimple_seq_add_stmt (&seq, g);
  tree lab1 = create_artificial_label (UNKNOWN_LOCATION);
  tree lab2 = create_artificial_label (UNKNOWN_LOCATION);
  tree lab3 = create_artificial_label (UNKNOWN_LOCATION);
  g = gimple_build_cond (NE_EXPR, cond, integer_zero_node, lab1, lab2);
  gimple_seq_add_stmt (&seq, g);
  g = gimple_build_label (lab1);
  gimple_seq_add_stmt (&seq, g);
  gimple_seq new_seq = copy_gimple_seq_and_replace_locals (stmt);
  gomp_for *new_stmt = as_a <gomp_for *> (new_seq);
  tree clause = build_omp_clause (gimple_location (stmt), OMP_CLAUSE__SIMT_);
  OMP_CLAUSE_CHAIN (clause) = gimple_omp_for_clauses (new_stmt);
  gimple_omp_for_set_clauses (new_stmt, clause);
  gimple_seq_add_stmt (&seq, new_stmt);
  g = gimple_build_goto (lab3);
  gimple_seq_add_stmt (&seq, g);
  g = gimple_build_label (lab2);
  gimple_seq_add_stmt (&seq, g);
  gimple_seq_add_stmt (&seq, stmt);
  g = gimple_build_label (lab3);
  gimple_seq_add_stmt (&seq, g);
  gimple_bind_set_body (bind, seq);
  update_stmt (bind);
  scan_omp_for (new_stmt, outer_ctx);
  scan_omp_for (stmt, outer_ctx)->simt_stmt = new_stmt;
}

/* Scan an OpenMP sections directive.  */

static void
scan_omp_sections (gomp_sections *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_ptr (stmt), ctx);
}

/* Scan an OpenMP single directive.  */

static void
scan_omp_single (gomp_single *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_ptr (stmt), ctx);

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

/* Return true if the CLAUSES of an omp target guarantee that the base pointers
   used in the corresponding offloaded function are restrict.  */

static bool
omp_target_base_pointers_restrict_p (tree clauses)
{
  /* The analysis relies on the GOMP_MAP_FORCE_* mapping kinds, which are only
     used by OpenACC.  */
  if (flag_openacc == 0)
    return false;

  /* I.  Basic example:

       void foo (void)
       {
	 unsigned int a[2], b[2];

	 #pragma acc kernels \
	   copyout (a) \
	   copyout (b)
	 {
	   a[0] = 0;
	   b[0] = 1;
	 }
       }

     After gimplification, we have:

       #pragma omp target oacc_kernels \
	 map(force_from:a [len: 8]) \
	 map(force_from:b [len: 8])
       {
	 a[0] = 0;
	 b[0] = 1;
       }

     Because both mappings have the force prefix, we know that they will be
     allocated when calling the corresponding offloaded function, which means we
     can mark the base pointers for a and b in the offloaded function as
     restrict.  */

  tree c;
  for (c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
    {
      if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_MAP)
	return false;

      switch (OMP_CLAUSE_MAP_KIND (c))
	{
	case GOMP_MAP_FORCE_ALLOC:
	case GOMP_MAP_FORCE_TO:
	case GOMP_MAP_FORCE_FROM:
	case GOMP_MAP_FORCE_TOFROM:
	  break;
	default:
	  return false;
	}
    }

  return true;
}

/* Scan a GIMPLE_OMP_TARGET.  */

static void
scan_omp_target (gomp_target *stmt, omp_context *outer_ctx)
{
  omp_context *ctx;
  tree name;
  bool offloaded = is_gimple_omp_offloaded (stmt);
  tree clauses = gimple_omp_target_clauses (stmt);

  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_data_t");
  name = build_decl (gimple_location (stmt),
		     TYPE_DECL, name, ctx->record_type);
  DECL_ARTIFICIAL (name) = 1;
  DECL_NAMELESS (name) = 1;
  TYPE_NAME (ctx->record_type) = name;
  TYPE_ARTIFICIAL (ctx->record_type) = 1;

  bool base_pointers_restrict = false;
  if (offloaded)
    {
      create_omp_child_function (ctx, false);
      gimple_omp_target_set_child_fn (stmt, ctx->cb.dst_fn);

      base_pointers_restrict = omp_target_base_pointers_restrict_p (clauses);
      if (base_pointers_restrict
	  && dump_file && (dump_flags & TDF_DETAILS))
	fprintf (dump_file,
		 "Base pointers in offloaded function are restrict\n");
    }

  scan_sharing_clauses (clauses, ctx, base_pointers_restrict);
  scan_omp (gimple_omp_body_ptr (stmt), ctx);

  if (TYPE_FIELDS (ctx->record_type) == NULL)
    ctx->record_type = ctx->receiver_decl = NULL;
  else
    {
      TYPE_FIELDS (ctx->record_type)
	= nreverse (TYPE_FIELDS (ctx->record_type));
      if (flag_checking)
	{
	  unsigned int align = DECL_ALIGN (TYPE_FIELDS (ctx->record_type));
	  for (tree field = TYPE_FIELDS (ctx->record_type);
	       field;
	       field = DECL_CHAIN (field))
	    gcc_assert (DECL_ALIGN (field) == align);
	}
      layout_type (ctx->record_type);
      if (offloaded)
	fixup_child_record_type (ctx);
    }
}

/* Scan an OpenMP teams directive.  */

static void
scan_omp_teams (gomp_teams *stmt, omp_context *outer_ctx)
{
  omp_context *ctx = new_omp_context (stmt, outer_ctx);
  scan_sharing_clauses (gimple_omp_teams_clauses (stmt), ctx);
  scan_omp (gimple_omp_body_ptr (stmt), ctx);
}

/* Check nesting restrictions.  */
static bool
check_omp_nesting_restrictions (gimple *stmt, omp_context *ctx)
{
  tree c;

  if (ctx && gimple_code (ctx->stmt) == GIMPLE_OMP_GRID_BODY)
    /* GRID_BODY is an artificial construct, nesting rules will be checked in
       the original copy of its contents.  */
    return true;

  /* No nesting of non-OpenACC STMT (that is, an OpenMP one, or a GOMP builtin)
     inside an OpenACC CTX.  */
  if (!(is_gimple_omp (stmt)
	&& is_gimple_omp_oacc (stmt))
      /* Except for atomic codes that we share with OpenMP.  */
      && !(gimple_code (stmt) == GIMPLE_OMP_ATOMIC_LOAD
	   || gimple_code (stmt) == GIMPLE_OMP_ATOMIC_STORE))
    {
      if (oacc_get_fn_attrib (cfun->decl) != NULL)
	{
	  error_at (gimple_location (stmt),
		    "non-OpenACC construct inside of OpenACC routine");
	  return false;
	}
      else
	for (omp_context *octx = ctx; octx != NULL; octx = octx->outer)
	  if (is_gimple_omp (octx->stmt)
	      && is_gimple_omp_oacc (octx->stmt))
	    {
	      error_at (gimple_location (stmt),
			"non-OpenACC construct inside of OpenACC region");
	      return false;
	    }
    }

  if (ctx != NULL)
    {
      if (gimple_code (ctx->stmt) == GIMPLE_OMP_FOR
	  && gimple_omp_for_kind (ctx->stmt) & GF_OMP_FOR_SIMD)
	{
	  c = NULL_TREE;
	  if (gimple_code (stmt) == GIMPLE_OMP_ORDERED)
	    {
	      c = gimple_omp_ordered_clauses (as_a <gomp_ordered *> (stmt));
	      if (omp_find_clause (c, OMP_CLAUSE_SIMD))
		{
		  if (omp_find_clause (c, OMP_CLAUSE_THREADS)
		      && (ctx->outer == NULL
			  || !gimple_omp_for_combined_into_p (ctx->stmt)
			  || gimple_code (ctx->outer->stmt) != GIMPLE_OMP_FOR
			  || (gimple_omp_for_kind (ctx->outer->stmt)
			      != GF_OMP_FOR_KIND_FOR)
			  || !gimple_omp_for_combined_p (ctx->outer->stmt)))
		    {
		      error_at (gimple_location (stmt),
				"%<ordered simd threads%> must be closely "
				"nested inside of %<for simd%> region");
		      return false;
		    }
		  return true;
		}
	    }
	  error_at (gimple_location (stmt),
		    "OpenMP constructs other than %<#pragma omp ordered simd%>"
		    " may not be nested inside %<simd%> region");
	  return false;
	}
      else if (gimple_code (ctx->stmt) == GIMPLE_OMP_TEAMS)
	{
	  if ((gimple_code (stmt) != GIMPLE_OMP_FOR
	       || ((gimple_omp_for_kind (stmt) != GF_OMP_FOR_KIND_DISTRIBUTE)
		   && (gimple_omp_for_kind (stmt) != GF_OMP_FOR_KIND_GRID_LOOP)))
	      && gimple_code (stmt) != GIMPLE_OMP_PARALLEL)
	    {
	      error_at (gimple_location (stmt),
			"only %<distribute%> or %<parallel%> regions are "
			"allowed to be strictly nested inside %<teams%> "
			"region");
	      return false;
	    }
	}
    }
  switch (gimple_code (stmt))
    {
    case GIMPLE_OMP_FOR:
      if (gimple_omp_for_kind (stmt) & GF_OMP_FOR_SIMD)
	return true;
      if (gimple_omp_for_kind (stmt) == GF_OMP_FOR_KIND_DISTRIBUTE)
	{
	  if (ctx != NULL && gimple_code (ctx->stmt) != GIMPLE_OMP_TEAMS)
	    {
	      error_at (gimple_location (stmt),
			"%<distribute%> region must be strictly nested "
			"inside %<teams%> construct");
	      return false;
	    }
	  return true;
	}
      /* We split taskloop into task and nested taskloop in it.  */
      if (gimple_omp_for_kind (stmt) == GF_OMP_FOR_KIND_TASKLOOP)
	return true;
      if (gimple_omp_for_kind (stmt) == GF_OMP_FOR_KIND_OACC_LOOP)
	{
	  bool ok = false;

	  if (ctx)
	    switch (gimple_code (ctx->stmt))
	      {
	      case GIMPLE_OMP_FOR:
		ok = (gimple_omp_for_kind (ctx->stmt)
		      == GF_OMP_FOR_KIND_OACC_LOOP);
		break;

	      case GIMPLE_OMP_TARGET:
		switch (gimple_omp_target_kind (ctx->stmt))
		  {
		  case GF_OMP_TARGET_KIND_OACC_PARALLEL:
		  case GF_OMP_TARGET_KIND_OACC_KERNELS:
		    ok = true;
		    break;

		  default:
		    break;
		  }

	      default:
		break;
	      }
	  else if (oacc_get_fn_attrib (current_function_decl))
	    ok = true;
	  if (!ok)
	    {
	      error_at (gimple_location (stmt),
			"OpenACC loop directive must be associated with"
			" an OpenACC compute region");
	      return false;
	    }
	}
      /* FALLTHRU */
    case GIMPLE_CALL:
      if (is_gimple_call (stmt)
	  && (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
	      == BUILT_IN_GOMP_CANCEL
	      || DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
		 == BUILT_IN_GOMP_CANCELLATION_POINT))
	{
	  const char *bad = NULL;
	  const char *kind = NULL;
	  const char *construct
	    = (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
	       == BUILT_IN_GOMP_CANCEL)
	      ? "#pragma omp cancel"
	      : "#pragma omp cancellation point";
	  if (ctx == NULL)
	    {
	      error_at (gimple_location (stmt), "orphaned %qs construct",
			construct);
	      return false;
	    }
	  switch (tree_fits_shwi_p (gimple_call_arg (stmt, 0))
		  ? tree_to_shwi (gimple_call_arg (stmt, 0))
		  : 0)
	    {
	    case 1:
	      if (gimple_code (ctx->stmt) != GIMPLE_OMP_PARALLEL)
		bad = "#pragma omp parallel";
	      else if (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
		       == BUILT_IN_GOMP_CANCEL
		       && !integer_zerop (gimple_call_arg (stmt, 1)))
		ctx->cancellable = true;
	      kind = "parallel";
	      break;
	    case 2:
	      if (gimple_code (ctx->stmt) != GIMPLE_OMP_FOR
		  || gimple_omp_for_kind (ctx->stmt) != GF_OMP_FOR_KIND_FOR)
		bad = "#pragma omp for";
	      else if (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
		       == BUILT_IN_GOMP_CANCEL
		       && !integer_zerop (gimple_call_arg (stmt, 1)))
		{
		  ctx->cancellable = true;
		  if (omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
				       OMP_CLAUSE_NOWAIT))
		    warning_at (gimple_location (stmt), 0,
				"%<#pragma omp cancel for%> inside "
				"%<nowait%> for construct");
		  if (omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
				       OMP_CLAUSE_ORDERED))
		    warning_at (gimple_location (stmt), 0,
				"%<#pragma omp cancel for%> inside "
				"%<ordered%> for construct");
		}
	      kind = "for";
	      break;
	    case 4:
	      if (gimple_code (ctx->stmt) != GIMPLE_OMP_SECTIONS
		  && gimple_code (ctx->stmt) != GIMPLE_OMP_SECTION)
		bad = "#pragma omp sections";
	      else if (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
		       == BUILT_IN_GOMP_CANCEL
		       && !integer_zerop (gimple_call_arg (stmt, 1)))
		{
		  if (gimple_code (ctx->stmt) == GIMPLE_OMP_SECTIONS)
		    {
		      ctx->cancellable = true;
		      if (omp_find_clause (gimple_omp_sections_clauses
								(ctx->stmt),
					   OMP_CLAUSE_NOWAIT))
			warning_at (gimple_location (stmt), 0,
				    "%<#pragma omp cancel sections%> inside "
				    "%<nowait%> sections construct");
		    }
		  else
		    {
		      gcc_assert (ctx->outer
				  && gimple_code (ctx->outer->stmt)
				     == GIMPLE_OMP_SECTIONS);
		      ctx->outer->cancellable = true;
		      if (omp_find_clause (gimple_omp_sections_clauses
							(ctx->outer->stmt),
					   OMP_CLAUSE_NOWAIT))
			warning_at (gimple_location (stmt), 0,
				    "%<#pragma omp cancel sections%> inside "
				    "%<nowait%> sections construct");
		    }
		}
	      kind = "sections";
	      break;
	    case 8:
	      if (gimple_code (ctx->stmt) != GIMPLE_OMP_TASK)
		bad = "#pragma omp task";
	      else
		{
		  for (omp_context *octx = ctx->outer;
		       octx; octx = octx->outer)
		    {
		      switch (gimple_code (octx->stmt))
			{
			case GIMPLE_OMP_TASKGROUP:
			  break;
			case GIMPLE_OMP_TARGET:
			  if (gimple_omp_target_kind (octx->stmt)
			      != GF_OMP_TARGET_KIND_REGION)
			    continue;
			  /* FALLTHRU */
			case GIMPLE_OMP_PARALLEL:
			case GIMPLE_OMP_TEAMS:
			  error_at (gimple_location (stmt),
				    "%<%s taskgroup%> construct not closely "
				    "nested inside of %<taskgroup%> region",
				    construct);
			  return false;
			default:
			  continue;
			}
		      break;
		    }
		  ctx->cancellable = true;
		}
	      kind = "taskgroup";
	      break;
	    default:
	      error_at (gimple_location (stmt), "invalid arguments");
	      return false;
	    }
	  if (bad)
	    {
	      error_at (gimple_location (stmt),
			"%<%s %s%> construct not closely nested inside of %qs",
			construct, kind, bad);
	      return false;
	    }
	}
      /* FALLTHRU */
    case GIMPLE_OMP_SECTIONS:
    case GIMPLE_OMP_SINGLE:
      for (; ctx != NULL; ctx = ctx->outer)
	switch (gimple_code (ctx->stmt))
	  {
	  case GIMPLE_OMP_FOR:
	    if (gimple_omp_for_kind (ctx->stmt) != GF_OMP_FOR_KIND_FOR
		&& gimple_omp_for_kind (ctx->stmt) != GF_OMP_FOR_KIND_TASKLOOP)
	      break;
	    /* FALLTHRU */
	  case GIMPLE_OMP_SECTIONS:
	  case GIMPLE_OMP_SINGLE:
	  case GIMPLE_OMP_ORDERED:
	  case GIMPLE_OMP_MASTER:
	  case GIMPLE_OMP_TASK:
	  case GIMPLE_OMP_CRITICAL:
	    if (is_gimple_call (stmt))
	      {
		if (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt))
		    != BUILT_IN_GOMP_BARRIER)
		  return true;
		error_at (gimple_location (stmt),
			  "barrier region may not be closely nested inside "
			  "of work-sharing, %<critical%>, %<ordered%>, "
			  "%<master%>, explicit %<task%> or %<taskloop%> "
			  "region");
		return false;
	      }
	    error_at (gimple_location (stmt),
		      "work-sharing region may not be closely nested inside "
		      "of work-sharing, %<critical%>, %<ordered%>, "
		      "%<master%>, explicit %<task%> or %<taskloop%> region");
	    return false;
	  case GIMPLE_OMP_PARALLEL:
	  case GIMPLE_OMP_TEAMS:
	    return true;
	  case GIMPLE_OMP_TARGET:
	    if (gimple_omp_target_kind (ctx->stmt)
		== GF_OMP_TARGET_KIND_REGION)
	      return true;
	    break;
	  default:
	    break;
	  }
      break;
    case GIMPLE_OMP_MASTER:
      for (; ctx != NULL; ctx = ctx->outer)
	switch (gimple_code (ctx->stmt))
	  {
	  case GIMPLE_OMP_FOR:
	    if (gimple_omp_for_kind (ctx->stmt) != GF_OMP_FOR_KIND_FOR
		&& gimple_omp_for_kind (ctx->stmt) != GF_OMP_FOR_KIND_TASKLOOP)
	      break;
	    /* FALLTHRU */
	  case GIMPLE_OMP_SECTIONS:
	  case GIMPLE_OMP_SINGLE:
	  case GIMPLE_OMP_TASK:
	    error_at (gimple_location (stmt),
		      "%<master%> region may not be closely nested inside "
		      "of work-sharing, explicit %<task%> or %<taskloop%> "
		      "region");
	    return false;
	  case GIMPLE_OMP_PARALLEL:
	  case GIMPLE_OMP_TEAMS:
	    return true;
	  case GIMPLE_OMP_TARGET:
	    if (gimple_omp_target_kind (ctx->stmt)
		== GF_OMP_TARGET_KIND_REGION)
	      return true;
	    break;
	  default:
	    break;
	  }
      break;
    case GIMPLE_OMP_TASK:
      for (c = gimple_omp_task_clauses (stmt); c; c = OMP_CLAUSE_CHAIN (c))
	if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEPEND
	    && (OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_SOURCE
		|| OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_SINK))
	  {
	    enum omp_clause_depend_kind kind = OMP_CLAUSE_DEPEND_KIND (c);
	    error_at (OMP_CLAUSE_LOCATION (c),
		      "%<depend(%s)%> is only allowed in %<omp ordered%>",
		      kind == OMP_CLAUSE_DEPEND_SOURCE ? "source" : "sink");
	    return false;
	  }
      break;
    case GIMPLE_OMP_ORDERED:
      for (c = gimple_omp_ordered_clauses (as_a <gomp_ordered *> (stmt));
	   c; c = OMP_CLAUSE_CHAIN (c))
	{
	  if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_DEPEND)
	    {
	      gcc_assert (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_THREADS
			  || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SIMD);
	      continue;
	    }
	  enum omp_clause_depend_kind kind = OMP_CLAUSE_DEPEND_KIND (c);
	  if (kind == OMP_CLAUSE_DEPEND_SOURCE
	      || kind == OMP_CLAUSE_DEPEND_SINK)
	    {
	      tree oclause;
	      /* Look for containing ordered(N) loop.  */
	      if (ctx == NULL
		  || gimple_code (ctx->stmt) != GIMPLE_OMP_FOR
		  || (oclause
			= omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
					   OMP_CLAUSE_ORDERED)) == NULL_TREE)
		{
		  error_at (OMP_CLAUSE_LOCATION (c),
			    "%<ordered%> construct with %<depend%> clause "
			    "must be closely nested inside an %<ordered%> "
			    "loop");
		  return false;
		}
	      else if (OMP_CLAUSE_ORDERED_EXPR (oclause) == NULL_TREE)
		{
		  error_at (OMP_CLAUSE_LOCATION (c),
			    "%<ordered%> construct with %<depend%> clause "
			    "must be closely nested inside a loop with "
			    "%<ordered%> clause with a parameter");
		  return false;
		}
	    }
	  else
	    {
	      error_at (OMP_CLAUSE_LOCATION (c),
			"invalid depend kind in omp %<ordered%> %<depend%>");
	      return false;
	    }
	}
      c = gimple_omp_ordered_clauses (as_a <gomp_ordered *> (stmt));
      if (omp_find_clause (c, OMP_CLAUSE_SIMD))
	{
	  /* ordered simd must be closely nested inside of simd region,
	     and simd region must not encounter constructs other than
	     ordered simd, therefore ordered simd may be either orphaned,
	     or ctx->stmt must be simd.  The latter case is handled already
	     earlier.  */
	  if (ctx != NULL)
	    {
	      error_at (gimple_location (stmt),
			"%<ordered%> %<simd%> must be closely nested inside "
			"%<simd%> region");
	      return false;
	    }
	}
      for (; ctx != NULL; ctx = ctx->outer)
	switch (gimple_code (ctx->stmt))
	  {
	  case GIMPLE_OMP_CRITICAL:
	  case GIMPLE_OMP_TASK:
	  case GIMPLE_OMP_ORDERED:
	  ordered_in_taskloop:
	    error_at (gimple_location (stmt),
		      "%<ordered%> region may not be closely nested inside "
		      "of %<critical%>, %<ordered%>, explicit %<task%> or "
		      "%<taskloop%> region");
	    return false;
	  case GIMPLE_OMP_FOR:
	    if (gimple_omp_for_kind (ctx->stmt) == GF_OMP_FOR_KIND_TASKLOOP)
	      goto ordered_in_taskloop;
	    if (omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
				 OMP_CLAUSE_ORDERED) == NULL)
	      {
		error_at (gimple_location (stmt),
			  "%<ordered%> region must be closely nested inside "
			  "a loop region with an %<ordered%> clause");
		return false;
	      }
	    return true;
	  case GIMPLE_OMP_TARGET:
	    if (gimple_omp_target_kind (ctx->stmt)
		!= GF_OMP_TARGET_KIND_REGION)
	      break;
	    /* FALLTHRU */
	  case GIMPLE_OMP_PARALLEL:
	  case GIMPLE_OMP_TEAMS:
	    error_at (gimple_location (stmt),
		      "%<ordered%> region must be closely nested inside "
		      "a loop region with an %<ordered%> clause");
	    return false;
	  default:
	    break;
	  }
      break;
    case GIMPLE_OMP_CRITICAL:
      {
	tree this_stmt_name
	  = gimple_omp_critical_name (as_a <gomp_critical *> (stmt));
	for (; ctx != NULL; ctx = ctx->outer)
	  if (gomp_critical *other_crit
	        = dyn_cast <gomp_critical *> (ctx->stmt))
	    if (this_stmt_name == gimple_omp_critical_name (other_crit))
	      {
		error_at (gimple_location (stmt),
			  "%<critical%> region may not be nested inside "
			   "a %<critical%> region with the same name");
		return false;
	      }
      }
      break;
    case GIMPLE_OMP_TEAMS:
      if (ctx == NULL
	  || gimple_code (ctx->stmt) != GIMPLE_OMP_TARGET
	  || gimple_omp_target_kind (ctx->stmt) != GF_OMP_TARGET_KIND_REGION)
	{
	  error_at (gimple_location (stmt),
		    "%<teams%> construct not closely nested inside of "
		    "%<target%> construct");
	  return false;
	}
      break;
    case GIMPLE_OMP_TARGET:
      for (c = gimple_omp_target_clauses (stmt); c; c = OMP_CLAUSE_CHAIN (c))
	if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEPEND
	    && (OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_SOURCE
		|| OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_SINK))
	  {
	    enum omp_clause_depend_kind kind = OMP_CLAUSE_DEPEND_KIND (c);
	    error_at (OMP_CLAUSE_LOCATION (c),
		      "%<depend(%s)%> is only allowed in %<omp ordered%>",
		      kind == OMP_CLAUSE_DEPEND_SOURCE ? "source" : "sink");
	    return false;
	  }
      if (is_gimple_omp_offloaded (stmt)
	  && oacc_get_fn_attrib (cfun->decl) != NULL)
	{
	  error_at (gimple_location (stmt),
		    "OpenACC region inside of OpenACC routine, nested "
		    "parallelism not supported yet");
	  return false;
	}
      for (; ctx != NULL; ctx = ctx->outer)
	{
	  if (gimple_code (ctx->stmt) != GIMPLE_OMP_TARGET)
	    {
	      if (is_gimple_omp (stmt)
		  && is_gimple_omp_oacc (stmt)
		  && is_gimple_omp (ctx->stmt))
		{
		  error_at (gimple_location (stmt),
			    "OpenACC construct inside of non-OpenACC region");
		  return false;
		}
	      continue;
	    }

	  const char *stmt_name, *ctx_stmt_name;
	  switch (gimple_omp_target_kind (stmt))
	    {
	    case GF_OMP_TARGET_KIND_REGION: stmt_name = "target"; break;
	    case GF_OMP_TARGET_KIND_DATA: stmt_name = "target data"; break;
	    case GF_OMP_TARGET_KIND_UPDATE: stmt_name = "target update"; break;
	    case GF_OMP_TARGET_KIND_ENTER_DATA:
	      stmt_name = "target enter data"; break;
	    case GF_OMP_TARGET_KIND_EXIT_DATA:
	      stmt_name = "target exit data"; break;
	    case GF_OMP_TARGET_KIND_OACC_PARALLEL: stmt_name = "parallel"; break;
	    case GF_OMP_TARGET_KIND_OACC_KERNELS: stmt_name = "kernels"; break;
	    case GF_OMP_TARGET_KIND_OACC_DATA: stmt_name = "data"; break;
	    case GF_OMP_TARGET_KIND_OACC_UPDATE: stmt_name = "update"; break;
	    case GF_OMP_TARGET_KIND_OACC_ENTER_EXIT_DATA:
	      stmt_name = "enter/exit data"; break;
	    case GF_OMP_TARGET_KIND_OACC_HOST_DATA: stmt_name = "host_data";
	      break;
	    default: gcc_unreachable ();
	    }
	  switch (gimple_omp_target_kind (ctx->stmt))
	    {
	    case GF_OMP_TARGET_KIND_REGION: ctx_stmt_name = "target"; break;
	    case GF_OMP_TARGET_KIND_DATA: ctx_stmt_name = "target data"; break;
	    case GF_OMP_TARGET_KIND_OACC_PARALLEL:
	      ctx_stmt_name = "parallel"; break;
	    case GF_OMP_TARGET_KIND_OACC_KERNELS:
	      ctx_stmt_name = "kernels"; break;
	    case GF_OMP_TARGET_KIND_OACC_DATA: ctx_stmt_name = "data"; break;
	    case GF_OMP_TARGET_KIND_OACC_HOST_DATA:
	      ctx_stmt_name = "host_data"; break;
	    default: gcc_unreachable ();
	    }

	  /* OpenACC/OpenMP mismatch?  */
	  if (is_gimple_omp_oacc (stmt)
	      != is_gimple_omp_oacc (ctx->stmt))
	    {
	      error_at (gimple_location (stmt),
			"%s %qs construct inside of %s %qs region",
			(is_gimple_omp_oacc (stmt)
			 ? "OpenACC" : "OpenMP"), stmt_name,
			(is_gimple_omp_oacc (ctx->stmt)
			 ? "OpenACC" : "OpenMP"), ctx_stmt_name);
	      return false;
	    }
	  if (is_gimple_omp_offloaded (ctx->stmt))
	    {
	      /* No GIMPLE_OMP_TARGET inside offloaded OpenACC CTX.  */
	      if (is_gimple_omp_oacc (ctx->stmt))
		{
		  error_at (gimple_location (stmt),
			    "%qs construct inside of %qs region",
			    stmt_name, ctx_stmt_name);
		  return false;
		}
	      else
		{
		  warning_at (gimple_location (stmt), 0,
			      "%qs construct inside of %qs region",
			      stmt_name, ctx_stmt_name);
		}
	    }
	}
      break;
    default:
      break;
    }
  return true;
}


/* Helper function scan_omp.

   Callback for walk_tree or operators in walk_gimple_stmt used to
   scan for OMP 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)
	{
	  tree repl = remap_decl (t, &ctx->cb);
	  gcc_checking_assert (TREE_CODE (repl) != ERROR_MARK);
	  *tp = repl;
	}
      break;

    default:
      if (ctx && TYPE_P (t))
	*tp = remap_type (t, &ctx->cb);
      else if (!DECL_P (t))
	{
	  *walk_subtrees = 1;
	  if (ctx)
	    {
	      tree tem = remap_type (TREE_TYPE (t), &ctx->cb);
	      if (tem != TREE_TYPE (t))
		{
		  if (TREE_CODE (t) == INTEGER_CST)
		    *tp = wide_int_to_tree (tem, wi::to_wide (t));
		  else
		    TREE_TYPE (t) = tem;
		}
	    }
	}
      break;
    }

  return NULL_TREE;