/* OpenMP directive matching and resolving.
   Copyright (C) 2005-2021 Free Software Foundation, Inc.
   Contributed by Jakub Jelinek

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 "gfortran.h"
#include "arith.h"
#include "match.h"
#include "parse.h"
#include "diagnostic.h"
#include "gomp-constants.h"

/* Match an end of OpenMP directive.  End of OpenMP directive is optional
   whitespace, followed by '\n' or comment '!'.  */

static match
gfc_match_omp_eos (void)
{
  locus old_loc;
  char c;

  old_loc = gfc_current_locus;
  gfc_gobble_whitespace ();

  c = gfc_next_ascii_char ();
  switch (c)
    {
    case '!':
      do
	c = gfc_next_ascii_char ();
      while (c != '\n');
      /* Fall through */

    case '\n':
      return MATCH_YES;
    }

  gfc_current_locus = old_loc;
  return MATCH_NO;
}

match
gfc_match_omp_eos_error (void)
{
  if (gfc_match_omp_eos() == MATCH_YES)
    return MATCH_YES;

  gfc_error ("Unexpected junk at %C");
  return MATCH_ERROR;
}


/* Free an omp_clauses structure.  */

void
gfc_free_omp_clauses (gfc_omp_clauses *c)
{
  int i;
  if (c == NULL)
    return;

  gfc_free_expr (c->if_expr);
  gfc_free_expr (c->final_expr);
  gfc_free_expr (c->num_threads);
  gfc_free_expr (c->chunk_size);
  gfc_free_expr (c->safelen_expr);
  gfc_free_expr (c->simdlen_expr);
  gfc_free_expr (c->num_teams);
  gfc_free_expr (c->device);
  gfc_free_expr (c->thread_limit);
  gfc_free_expr (c->dist_chunk_size);
  gfc_free_expr (c->grainsize);
  gfc_free_expr (c->hint);
  gfc_free_expr (c->num_tasks);
  gfc_free_expr (c->priority);
  gfc_free_expr (c->detach);
  for (i = 0; i < OMP_IF_LAST; i++)
    gfc_free_expr (c->if_exprs[i]);
  gfc_free_expr (c->async_expr);
  gfc_free_expr (c->gang_num_expr);
  gfc_free_expr (c->gang_static_expr);
  gfc_free_expr (c->worker_expr);
  gfc_free_expr (c->vector_expr);
  gfc_free_expr (c->num_gangs_expr);
  gfc_free_expr (c->num_workers_expr);
  gfc_free_expr (c->vector_length_expr);
  for (i = 0; i < OMP_LIST_NUM; i++)
    gfc_free_omp_namelist (c->lists[i]);
  gfc_free_expr_list (c->wait_list);
  gfc_free_expr_list (c->tile_list);
  free (CONST_CAST (char *, c->critical_name));
  free (c);
}

/* Free oacc_declare structures.  */

void
gfc_free_oacc_declare_clauses (struct gfc_oacc_declare *oc)
{
  struct gfc_oacc_declare *decl = oc;

  do
    {
      struct gfc_oacc_declare *next;

      next = decl->next;
      gfc_free_omp_clauses (decl->clauses);
      free (decl);
      decl = next;
    }
  while (decl);
}

/* Free expression list. */
void
gfc_free_expr_list (gfc_expr_list *list)
{
  gfc_expr_list *n;

  for (; list; list = n)
    {
      n = list->next;
      free (list);
    }
}

/* Free an !$omp declare simd construct list.  */

void
gfc_free_omp_declare_simd (gfc_omp_declare_simd *ods)
{
  if (ods)
    {
      gfc_free_omp_clauses (ods->clauses);
      free (ods);
    }
}

void
gfc_free_omp_declare_simd_list (gfc_omp_declare_simd *list)
{
  while (list)
    {
      gfc_omp_declare_simd *current = list;
      list = list->next;
      gfc_free_omp_declare_simd (current);
    }
}

/* Free an !$omp declare reduction.  */

void
gfc_free_omp_udr (gfc_omp_udr *omp_udr)
{
  if (omp_udr)
    {
      gfc_free_omp_udr (omp_udr->next);
      gfc_free_namespace (omp_udr->combiner_ns);
      if (omp_udr->initializer_ns)
	gfc_free_namespace (omp_udr->initializer_ns);
      free (omp_udr);
    }
}


static gfc_omp_udr *
gfc_find_omp_udr (gfc_namespace *ns, const char *name, gfc_typespec *ts)
{
  gfc_symtree *st;

  if (ns == NULL)
    ns = gfc_current_ns;
  do
    {
      gfc_omp_udr *omp_udr;

      st = gfc_find_symtree (ns->omp_udr_root, name);
      if (st != NULL)
	{
	  for (omp_udr = st->n.omp_udr; omp_udr; omp_udr = omp_udr->next)
	    if (ts == NULL)
	      return omp_udr;
	    else if (gfc_compare_types (&omp_udr->ts, ts))
	      {
		if (ts->type == BT_CHARACTER)
		  {
		    if (omp_udr->ts.u.cl->length == NULL)
		      return omp_udr;
		    if (ts->u.cl->length == NULL)
		      continue;
		    if (gfc_compare_expr (omp_udr->ts.u.cl->length,
					  ts->u.cl->length,
					  INTRINSIC_EQ) != 0)
		      continue;
		  }
		return omp_udr;
	      }
	}

      /* Don't escape an interface block.  */
      if (ns && !ns->has_import_set
	  && ns->proc_name && ns->proc_name->attr.if_source == IFSRC_IFBODY)
	break;

      ns = ns->parent;
    }
  while (ns != NULL);

  return NULL;
}


/* Match a variable/common block list and construct a namelist from it.  */

static match
gfc_match_omp_variable_list (const char *str, gfc_omp_namelist **list,
			     bool allow_common, bool *end_colon = NULL,
			     gfc_omp_namelist ***headp = NULL,
			     bool allow_sections = false,
			     bool allow_derived = false)
{
  gfc_omp_namelist *head, *tail, *p;
  locus old_loc, cur_loc;
  char n[GFC_MAX_SYMBOL_LEN+1];
  gfc_symbol *sym;
  match m;
  gfc_symtree *st;

  head = tail = NULL;

  old_loc = gfc_current_locus;

  m = gfc_match (str);
  if (m != MATCH_YES)
    return m;

  for (;;)
    {
      cur_loc = gfc_current_locus;
      m = gfc_match_symbol (&sym, 1);
      switch (m)
	{
	case MATCH_YES:
	  gfc_expr *expr;
	  expr = NULL;
	  gfc_gobble_whitespace ();
	  if ((allow_sections && gfc_peek_ascii_char () == '(')
	      || (allow_derived && gfc_peek_ascii_char () == '%'))
	    {
	      gfc_current_locus = cur_loc;
	      m = gfc_match_variable (&expr, 0);
	      switch (m)
		{
		case MATCH_ERROR:
		  goto cleanup;
		case MATCH_NO:
		  goto syntax;
		default:
		  break;
		}
	      if (gfc_is_coindexed (expr))
		{
		  gfc_error ("List item shall not be coindexed at %C");
		  goto cleanup;
		}
	    }
	  gfc_set_sym_referenced (sym);
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  tail->sym = sym;
	  tail->expr = expr;
	  tail->where = cur_loc;
	  goto next_item;
	case MATCH_NO:
	  break;
	case MATCH_ERROR:
	  goto cleanup;
	}

      if (!allow_common)
	goto syntax;

      m = gfc_match (" / %n /", n);
      if (m == MATCH_ERROR)
	goto cleanup;
      if (m == MATCH_NO)
	goto syntax;

      st = gfc_find_symtree (gfc_current_ns->common_root, n);
      if (st == NULL)
	{
	  gfc_error ("COMMON block /%s/ not found at %C", n);
	  goto cleanup;
	}
      for (sym = st->n.common->head; sym; sym = sym->common_next)
	{
	  gfc_set_sym_referenced (sym);
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  tail->sym = sym;
	  tail->where = cur_loc;
	}

    next_item:
      if (end_colon && gfc_match_char (':') == MATCH_YES)
	{
	  *end_colon = true;
	  break;
	}
      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  while (*list)
    list = &(*list)->next;

  *list = head;
  if (headp)
    *headp = list;
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in OpenMP variable list at %C");

cleanup:
  gfc_free_omp_namelist (head);
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}

/* Match a variable/procedure/common block list and construct a namelist
   from it.  */

static match
gfc_match_omp_to_link (const char *str, gfc_omp_namelist **list)
{
  gfc_omp_namelist *head, *tail, *p;
  locus old_loc, cur_loc;
  char n[GFC_MAX_SYMBOL_LEN+1];
  gfc_symbol *sym;
  match m;
  gfc_symtree *st;

  head = tail = NULL;

  old_loc = gfc_current_locus;

  m = gfc_match (str);
  if (m != MATCH_YES)
    return m;

  for (;;)
    {
      cur_loc = gfc_current_locus;
      m = gfc_match_symbol (&sym, 1);
      switch (m)
	{
	case MATCH_YES:
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  tail->sym = sym;
	  tail->where = cur_loc;
	  goto next_item;
	case MATCH_NO:
	  break;
	case MATCH_ERROR:
	  goto cleanup;
	}

      m = gfc_match (" / %n /", n);
      if (m == MATCH_ERROR)
	goto cleanup;
      if (m == MATCH_NO)
	goto syntax;

      st = gfc_find_symtree (gfc_current_ns->common_root, n);
      if (st == NULL)
	{
	  gfc_error ("COMMON block /%s/ not found at %C", n);
	  goto cleanup;
	}
      p = gfc_get_omp_namelist ();
      if (head == NULL)
	head = tail = p;
      else
	{
	  tail->next = p;
	  tail = tail->next;
	}
      tail->u.common = st->n.common;
      tail->where = cur_loc;

    next_item:
      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  while (*list)
    list = &(*list)->next;

  *list = head;
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in OpenMP variable list at %C");

cleanup:
  gfc_free_omp_namelist (head);
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}

/* Match detach(event-handle).  */

static match
gfc_match_omp_detach (gfc_expr **expr)
{
  locus old_loc = gfc_current_locus;

  if (gfc_match ("detach ( ") != MATCH_YES)
    goto syntax_error;

  if (gfc_match_variable (expr, 0) != MATCH_YES)
    goto syntax_error;

  if ((*expr)->ts.type != BT_INTEGER || (*expr)->ts.kind != gfc_c_intptr_kind)
    {
      gfc_error ("%qs at %L should be of type "
		 "integer(kind=omp_event_handle_kind)",
		 (*expr)->symtree->n.sym->name, &(*expr)->where);
      return MATCH_ERROR;
    }

  if (gfc_match_char (')') != MATCH_YES)
    goto syntax_error;

  return MATCH_YES;

syntax_error:
   gfc_error ("Syntax error in OpenMP detach clause at %C");
   gfc_current_locus = old_loc;
   return MATCH_ERROR;

}

/* Match depend(sink : ...) construct a namelist from it.  */

static match
gfc_match_omp_depend_sink (gfc_omp_namelist **list)
{
  gfc_omp_namelist *head, *tail, *p;
  locus old_loc, cur_loc;
  gfc_symbol *sym;

  head = tail = NULL;

  old_loc = gfc_current_locus;

  for (;;)
    {
      cur_loc = gfc_current_locus;
      switch (gfc_match_symbol (&sym, 1))
	{
	case MATCH_YES:
	  gfc_set_sym_referenced (sym);
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    {
	      head = tail = p;
	      head->u.depend_op = OMP_DEPEND_SINK_FIRST;
	    }
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	      tail->u.depend_op = OMP_DEPEND_SINK;
	    }
	  tail->sym = sym;
	  tail->expr = NULL;
	  tail->where = cur_loc;
	  if (gfc_match_char ('+') == MATCH_YES)
	    {
	      if (gfc_match_literal_constant (&tail->expr, 0) != MATCH_YES)
		goto syntax;
	    }
	  else if (gfc_match_char ('-') == MATCH_YES)
	    {
	      if (gfc_match_literal_constant (&tail->expr, 0) != MATCH_YES)
		goto syntax;
	      tail->expr = gfc_uminus (tail->expr);
	    }
	  break;
	case MATCH_NO:
	  goto syntax;
	case MATCH_ERROR:
	  goto cleanup;
	}

      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  while (*list)
    list = &(*list)->next;

  *list = head;
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in OpenMP DEPEND SINK list at %C");

cleanup:
  gfc_free_omp_namelist (head);
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}

static match
match_oacc_expr_list (const char *str, gfc_expr_list **list,
		      bool allow_asterisk)
{
  gfc_expr_list *head, *tail, *p;
  locus old_loc;
  gfc_expr *expr;
  match m;

  head = tail = NULL;

  old_loc = gfc_current_locus;

  m = gfc_match (str);
  if (m != MATCH_YES)
    return m;

  for (;;)
    {
      m = gfc_match_expr (&expr);
      if (m == MATCH_YES || allow_asterisk)
	{
	  p = gfc_get_expr_list ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  if (m == MATCH_YES)
	    tail->expr = expr;
	  else if (gfc_match (" *") != MATCH_YES)
	    goto syntax;
	  goto next_item;
	}
      if (m == MATCH_ERROR)
	goto cleanup;
      goto syntax;

    next_item:
      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  while (*list)
    list = &(*list)->next;

  *list = head;
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in OpenACC expression list at %C");

cleanup:
  gfc_free_expr_list (head);
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}

static match
match_oacc_clause_gwv (gfc_omp_clauses *cp, unsigned gwv)
{
  match ret = MATCH_YES;

  if (gfc_match (" ( ") != MATCH_YES)
    return MATCH_NO;

  if (gwv == GOMP_DIM_GANG)
    {
        /* The gang clause accepts two optional arguments, num and static.
	 The num argument may either be explicit (num: <val>) or
	 implicit without (<val> without num:).  */

      while (ret == MATCH_YES)
	{
	  if (gfc_match (" static :") == MATCH_YES)
	    {
	      if (cp->gang_static)
		return MATCH_ERROR;
	      else
		cp->gang_static = true;
	      if (gfc_match_char ('*') == MATCH_YES)
		cp->gang_static_expr = NULL;
	      else if (gfc_match (" %e ", &cp->gang_static_expr) != MATCH_YES)
		return MATCH_ERROR;
	    }
	  else
	    {
	      if (cp->gang_num_expr)
		return MATCH_ERROR;

	      /* The 'num' argument is optional.  */
	      gfc_match (" num :");

	      if (gfc_match (" %e ", &cp->gang_num_expr) != MATCH_YES)
		return MATCH_ERROR;
	    }

	  ret = gfc_match (" , ");
	}
    }
  else if (gwv == GOMP_DIM_WORKER)
    {
      /* The 'num' argument is optional.  */
      gfc_match (" num :");

      if (gfc_match (" %e ", &cp->worker_expr) != MATCH_YES)
	return MATCH_ERROR;
    }
  else if (gwv == GOMP_DIM_VECTOR)
    {
      /* The 'length' argument is optional.  */
      gfc_match (" length :");

      if (gfc_match (" %e ", &cp->vector_expr) != MATCH_YES)
	return MATCH_ERROR;
    }
  else
    gfc_fatal_error ("Unexpected OpenACC parallelism.");

  return gfc_match (" )");
}

static match
gfc_match_oacc_clause_link (const char *str, gfc_omp_namelist **list)
{
  gfc_omp_namelist *head = NULL;
  gfc_omp_namelist *tail, *p;
  locus old_loc;
  char n[GFC_MAX_SYMBOL_LEN+1];
  gfc_symbol *sym;
  match m;
  gfc_symtree *st;

  old_loc = gfc_current_locus;

  m = gfc_match (str);
  if (m != MATCH_YES)
    return m;

  m = gfc_match (" (");

  for (;;)
    {
      m = gfc_match_symbol (&sym, 0);
      switch (m)
	{
	case MATCH_YES:
	  if (sym->attr.in_common)
	    {
	      gfc_error_now ("Variable at %C is an element of a COMMON block");
	      goto cleanup;
	    }
	  gfc_set_sym_referenced (sym);
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  tail->sym = sym;
	  tail->expr = NULL;
	  tail->where = gfc_current_locus;
	  goto next_item;
	case MATCH_NO:
	  break;

	case MATCH_ERROR:
	  goto cleanup;
	}

      m = gfc_match (" / %n /", n);
      if (m == MATCH_ERROR)
	goto cleanup;
      if (m == MATCH_NO || n[0] == '\0')
	goto syntax;

      st = gfc_find_symtree (gfc_current_ns->common_root, n);
      if (st == NULL)
	{
	  gfc_error ("COMMON block /%s/ not found at %C", n);
	  goto cleanup;
	}

      for (sym = st->n.common->head; sym; sym = sym->common_next)
	{
	  gfc_set_sym_referenced (sym);
	  p = gfc_get_omp_namelist ();
	  if (head == NULL)
	    head = tail = p;
	  else
	    {
	      tail->next = p;
	      tail = tail->next;
	    }
	  tail->sym = sym;
	  tail->where = gfc_current_locus;
	}

    next_item:
      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after !$ACC DECLARE at %C");
      goto cleanup;
    }

  while (*list)
    list = &(*list)->next;
  *list = head;
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in !$ACC DECLARE list at %C");

cleanup:
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}

/* OpenMP clauses.  */
enum omp_mask1
{
  OMP_CLAUSE_PRIVATE,
  OMP_CLAUSE_FIRSTPRIVATE,
  OMP_CLAUSE_LASTPRIVATE,
  OMP_CLAUSE_COPYPRIVATE,
  OMP_CLAUSE_SHARED,
  OMP_CLAUSE_COPYIN,
  OMP_CLAUSE_REDUCTION,
  OMP_CLAUSE_IN_REDUCTION,
  OMP_CLAUSE_TASK_REDUCTION,
  OMP_CLAUSE_IF,
  OMP_CLAUSE_NUM_THREADS,
  OMP_CLAUSE_SCHEDULE,
  OMP_CLAUSE_DEFAULT,
  OMP_CLAUSE_ORDER,
  OMP_CLAUSE_ORDERED,
  OMP_CLAUSE_COLLAPSE,
  OMP_CLAUSE_UNTIED,
  OMP_CLAUSE_FINAL,
  OMP_CLAUSE_MERGEABLE,
  OMP_CLAUSE_ALIGNED,
  OMP_CLAUSE_DEPEND,
  OMP_CLAUSE_INBRANCH,
  OMP_CLAUSE_LINEAR,
  OMP_CLAUSE_NOTINBRANCH,
  OMP_CLAUSE_PROC_BIND,
  OMP_CLAUSE_SAFELEN,
  OMP_CLAUSE_SIMDLEN,
  OMP_CLAUSE_UNIFORM,
  OMP_CLAUSE_DEVICE,
  OMP_CLAUSE_MAP,
  OMP_CLAUSE_TO,
  OMP_CLAUSE_FROM,
  OMP_CLAUSE_NUM_TEAMS,
  OMP_CLAUSE_THREAD_LIMIT,
  OMP_CLAUSE_DIST_SCHEDULE,
  OMP_CLAUSE_DEFAULTMAP,
  OMP_CLAUSE_GRAINSIZE,
  OMP_CLAUSE_HINT,
  OMP_CLAUSE_IS_DEVICE_PTR,
  OMP_CLAUSE_LINK,
  OMP_CLAUSE_NOGROUP,
  OMP_CLAUSE_NOTEMPORAL,
  OMP_CLAUSE_NUM_TASKS,
  OMP_CLAUSE_PRIORITY,
  OMP_CLAUSE_SIMD,
  OMP_CLAUSE_THREADS,
  OMP_CLAUSE_USE_DEVICE_PTR,
  OMP_CLAUSE_USE_DEVICE_ADDR,  /* OpenMP 5.0.  */
  OMP_CLAUSE_DEVICE_TYPE,  /* OpenMP 5.0.  */
  OMP_CLAUSE_ATOMIC,  /* OpenMP 5.0.  */
  OMP_CLAUSE_CAPTURE,  /* OpenMP 5.0.  */
  OMP_CLAUSE_MEMORDER,  /* OpenMP 5.0.  */
  OMP_CLAUSE_DETACH,  /* OpenMP 5.0.  */
  OMP_CLAUSE_NOWAIT,
  /* This must come last.  */
  OMP_MASK1_LAST
};

/* OpenACC 2.0+ specific clauses. */
enum omp_mask2
{
  OMP_CLAUSE_ASYNC,
  OMP_CLAUSE_NUM_GANGS,
  OMP_CLAUSE_NUM_WORKERS,
  OMP_CLAUSE_VECTOR_LENGTH,
  OMP_CLAUSE_COPY,
  OMP_CLAUSE_COPYOUT,
  OMP_CLAUSE_CREATE,
  OMP_CLAUSE_NO_CREATE,
  OMP_CLAUSE_PRESENT,
  OMP_CLAUSE_DEVICEPTR,
  OMP_CLAUSE_GANG,
  OMP_CLAUSE_WORKER,
  OMP_CLAUSE_VECTOR,
  OMP_CLAUSE_SEQ,
  OMP_CLAUSE_INDEPENDENT,
  OMP_CLAUSE_USE_DEVICE,
  OMP_CLAUSE_DEVICE_RESIDENT,
  OMP_CLAUSE_HOST_SELF,
  OMP_CLAUSE_WAIT,
  OMP_CLAUSE_DELETE,
  OMP_CLAUSE_AUTO,
  OMP_CLAUSE_TILE,
  OMP_CLAUSE_IF_PRESENT,
  OMP_CLAUSE_FINALIZE,
  OMP_CLAUSE_ATTACH,
  /* This must come last.  */
  OMP_MASK2_LAST
};

struct omp_inv_mask;

/* Customized bitset for up to 128-bits.
   The two enums above provide bit numbers to use, and which of the
   two enums it is determines which of the two mask fields is used.
   Supported operations are defining a mask, like:
   #define XXX_CLAUSES \
     (omp_mask (OMP_CLAUSE_XXX) | OMP_CLAUSE_YYY | OMP_CLAUSE_ZZZ)
   oring such bitsets together or removing selected bits:
   (XXX_CLAUSES | YYY_CLAUSES) & ~(omp_mask (OMP_CLAUSE_VVV))
   and testing individual bits:
   if (mask & OMP_CLAUSE_UUU)  */

struct omp_mask {
  const uint64_t mask1;
  const uint64_t mask2;
  inline omp_mask ();
  inline omp_mask (omp_mask1);
  inline omp_mask (omp_mask2);
  inline omp_mask (uint64_t, uint64_t);
  inline omp_mask operator| (omp_mask1) const;
  inline omp_mask operator| (omp_mask2) const;
  inline omp_mask operator| (omp_mask) const;
  inline omp_mask operator& (const omp_inv_mask &) const;
  inline bool operator& (omp_mask1) const;
  inline bool operator& (omp_mask2) const;
  inline omp_inv_mask operator~ () const;
};

struct omp_inv_mask : public omp_mask {
  inline omp_inv_mask (const omp_mask &);
};

omp_mask::omp_mask () : mask1 (0), mask2 (0)
{
}

omp_mask::omp_mask (omp_mask1 m) : mask1 (((uint64_t) 1) << m), mask2 (0)
{
}

omp_mask::omp_mask (omp_mask2 m) : mask1 (0), mask2 (((uint64_t) 1) << m)
{
}

omp_mask::omp_mask (uint64_t m1, uint64_t m2) : mask1 (m1), mask2 (m2)
{
}

omp_mask
omp_mask::operator| (omp_mask1 m) const
{
  return omp_mask (mask1 | (((uint64_t) 1) << m), mask2);
}

omp_mask
omp_mask::operator| (omp_mask2 m) const
{
  return omp_mask (mask1, mask2 | (((uint64_t) 1) << m));
}

omp_mask
omp_mask::operator| (omp_mask m) const
{
  return omp_mask (mask1 | m.mask1, mask2 | m.mask2);
}

omp_mask
omp_mask::operator& (const omp_inv_mask &m) const
{
  return omp_mask (mask1 & ~m.mask1, mask2 & ~m.mask2);
}

bool
omp_mask::operator& (omp_mask1 m) const
{
  return (mask1 & (((uint64_t) 1) << m)) != 0;
}

bool
omp_mask::operator& (omp_mask2 m) const
{
  return (mask2 & (((uint64_t) 1) << m)) != 0;
}

omp_inv_mask
omp_mask::operator~ () const
{
  return omp_inv_mask (*this);
}

omp_inv_mask::omp_inv_mask (const omp_mask &m) : omp_mask (m)
{
}

/* Helper function for OpenACC and OpenMP clauses involving memory
   mapping.  */

static bool
gfc_match_omp_map_clause (gfc_omp_namelist **list, gfc_omp_map_op map_op,
			  bool allow_common, bool allow_derived)
{
  gfc_omp_namelist **head = NULL;
  if (gfc_match_omp_variable_list ("", list, allow_common, NULL, &head, true,
				   allow_derived)
      == MATCH_YES)
    {
      gfc_omp_namelist *n;
      for (n = *head; n; n = n->next)
	n->u.map_op = map_op;
      return true;
    }

  return false;
}

/* reduction ( reduction-modifier, reduction-operator : variable-list )
   in_reduction ( reduction-operator : variable-list )
   task_reduction ( reduction-operator : variable-list )  */

static match
gfc_match_omp_clause_reduction (char pc, gfc_omp_clauses *c, bool openacc,
				bool allow_derived)
{
  if (pc == 'r' && gfc_match ("reduction ( ") != MATCH_YES)
    return MATCH_NO;
  else if (pc == 'i' && gfc_match ("in_reduction ( ") != MATCH_YES)
    return MATCH_NO;
  else if (pc == 't' && gfc_match ("task_reduction ( ") != MATCH_YES)
    return MATCH_NO;

  locus old_loc = gfc_current_locus;
  int list_idx = 0;

  if (pc == 'r' && !openacc)
    {
      if (gfc_match ("inscan") == MATCH_YES)
	list_idx = OMP_LIST_REDUCTION_INSCAN;
      else if (gfc_match ("task") == MATCH_YES)
	list_idx = OMP_LIST_REDUCTION_TASK;
      else if (gfc_match ("default") == MATCH_YES)
	list_idx = OMP_LIST_REDUCTION;
      if (list_idx != 0 && gfc_match (", ") != MATCH_YES)
	{
	  gfc_error ("Comma expected at %C");
	  gfc_current_locus = old_loc;
	  return MATCH_NO;
	}
      if (list_idx == 0)
	list_idx = OMP_LIST_REDUCTION;
    }
  else if (pc == 'i')
    list_idx = OMP_LIST_IN_REDUCTION;
  else if (pc == 't')
    list_idx = OMP_LIST_TASK_REDUCTION;
  else
    list_idx = OMP_LIST_REDUCTION;

  gfc_omp_reduction_op rop = OMP_REDUCTION_NONE;
  char buffer[GFC_MAX_SYMBOL_LEN + 3];
  if (gfc_match_char ('+') == MATCH_YES)
    rop = OMP_REDUCTION_PLUS;
  else if (gfc_match_char ('*') == MATCH_YES)
    rop = OMP_REDUCTION_TIMES;
  else if (gfc_match_char ('-') == MATCH_YES)
    rop = OMP_REDUCTION_MINUS;
  else if (gfc_match (".and.") == MATCH_YES)
    rop = OMP_REDUCTION_AND;
  else if (gfc_match (".or.") == MATCH_YES)
    rop = OMP_REDUCTION_OR;
  else if (gfc_match (".eqv.") == MATCH_YES)
    rop = OMP_REDUCTION_EQV;
  else if (gfc_match (".neqv.") == MATCH_YES)
    rop = OMP_REDUCTION_NEQV;
  if (rop != OMP_REDUCTION_NONE)
    snprintf (buffer, sizeof buffer, "operator %s",
	      gfc_op2string ((gfc_intrinsic_op) rop));
  else if (gfc_match_defined_op_name (buffer + 1, 1) == MATCH_YES)
    {
      buffer[0] = '.';
      strcat (buffer, ".");
    }
  else if (gfc_match_name (buffer) == MATCH_YES)
    {
      gfc_symbol *sym;
      const char *n = buffer;

      gfc_find_symbol (buffer, NULL, 1, &sym);
      if (sym != NULL)
	{
	  if (sym->attr.intrinsic)
	    n = sym->name;
	  else if ((sym->attr.flavor != FL_UNKNOWN
		    && sym->attr.flavor != FL_PROCEDURE)
		   || sym->attr.external
		   || sym->attr.generic
		   || sym->attr.entry
		   || sym->attr.result
		   || sym->attr.dummy
		   || sym->attr.subroutine
		   || sym->attr.pointer
		   || sym->attr.target
		   || sym->attr.cray_pointer
		   || sym->attr.cray_pointee
		   || (sym->attr.proc != PROC_UNKNOWN
		       && sym->attr.proc != PROC_INTRINSIC)
		   || sym->attr.if_source != IFSRC_UNKNOWN
		   || sym == sym->ns->proc_name)
		{
		  sym = NULL;
		  n = NULL;
		}
	      else
		n = sym->name;
	    }
	  if (n == NULL)
	    rop = OMP_REDUCTION_NONE;
	  else if (strcmp (n, "max") == 0)
	    rop = OMP_REDUCTION_MAX;
	  else if (strcmp (n, "min") == 0)
	    rop = OMP_REDUCTION_MIN;
	  else if (strcmp (n, "iand") == 0)
	    rop = OMP_REDUCTION_IAND;
	  else if (strcmp (n, "ior") == 0)
	    rop = OMP_REDUCTION_IOR;
	  else if (strcmp (n, "ieor") == 0)
	    rop = OMP_REDUCTION_IEOR;
	  if (rop != OMP_REDUCTION_NONE
	      && sym != NULL
	      && ! sym->attr.intrinsic
	      && ! sym->attr.use_assoc
	      && ((sym->attr.flavor == FL_UNKNOWN
		   && !gfc_add_flavor (&sym->attr, FL_PROCEDURE,
					      sym->name, NULL))
		  || !gfc_add_intrinsic (&sym->attr, NULL)))
	    rop = OMP_REDUCTION_NONE;
    }
  else
    buffer[0] = '\0';
  gfc_omp_udr *udr = (buffer[0] ? gfc_find_omp_udr (gfc_current_ns, buffer, NULL)
				: NULL);
  gfc_omp_namelist **head = NULL;
  if (rop == OMP_REDUCTION_NONE && udr)
    rop = OMP_REDUCTION_USER;

  if (gfc_match_omp_variable_list (" :", &c->lists[list_idx], false, NULL,
				   &head, openacc, allow_derived) != MATCH_YES)
    {
      gfc_current_locus = old_loc;
      return MATCH_NO;
    }
  gfc_omp_namelist *n;
  if (rop == OMP_REDUCTION_NONE)
    {
      n = *head;
      *head = NULL;
      gfc_error_now ("!$OMP DECLARE REDUCTION %s not found at %L",
		     buffer, &old_loc);
      gfc_free_omp_namelist (n);
    }
  else
    for (n = *head; n; n = n->next)
      {
	n->u.reduction_op = rop;
	if (udr)
	  {
	    n->udr = gfc_get_omp_namelist_udr ();
	    n->udr->udr = udr;
	  }
     }
  return MATCH_YES;
}

/* Match OpenMP and OpenACC directive clauses. MASK is a bitmask of
   clauses that are allowed for a particular directive.  */

static match
gfc_match_omp_clauses (gfc_omp_clauses **cp, const omp_mask mask,
		       bool first = true, bool needs_space = true,
		       bool openacc = false)
{
  gfc_omp_clauses *c = gfc_get_omp_clauses ();
  locus old_loc;
  /* Determine whether we're dealing with an OpenACC directive that permits
     derived type member accesses.  This in particular disallows
     "!$acc declare" from using such accesses, because it's not clear if/how
     that should work.  */
  bool allow_derived = (openacc
			&& ((mask & OMP_CLAUSE_ATTACH)
			    || (mask & OMP_CLAUSE_DETACH)
			    || (mask & OMP_CLAUSE_HOST_SELF)));

  gcc_checking_assert (OMP_MASK1_LAST <= 64 && OMP_MASK2_LAST <= 64);
  *cp = NULL;
  while (1)
    {
      if ((first || gfc_match_char (',') != MATCH_YES)
	  && (needs_space && gfc_match_space () != MATCH_YES))
	break;
      needs_space = false;
      first = false;
      gfc_gobble_whitespace ();
      bool end_colon;
      gfc_omp_namelist **head;
      old_loc = gfc_current_locus;
      char pc = gfc_peek_ascii_char ();
      switch (pc)
	{
	case 'a':
	  end_colon = false;
	  head = NULL;
	  if ((mask & OMP_CLAUSE_ALIGNED)
	      && gfc_match_omp_variable_list ("aligned (",
					      &c->lists[OMP_LIST_ALIGNED],
					      false, &end_colon,
					      &head) == MATCH_YES)
	    {
	      gfc_expr *alignment = NULL;
	      gfc_omp_namelist *n;

	      if (end_colon && gfc_match (" %e )", &alignment) != MATCH_YES)
		{
		  gfc_free_omp_namelist (*head);
		  gfc_current_locus = old_loc;
		  *head = NULL;
		  break;
		}
	      for (n = *head; n; n = n->next)
		if (n->next && alignment)
		  n->expr = gfc_copy_expr (alignment);
		else
		  n->expr = alignment;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("acq_rel") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_ACQ_REL;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("acquire") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_ACQUIRE;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_ASYNC)
	      && !c->async
	      && gfc_match ("async") == MATCH_YES)
	    {
	      c->async = true;
	      match m = gfc_match (" ( %e )", &c->async_expr);
	      if (m == MATCH_ERROR)
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      else if (m == MATCH_NO)
		{
		  c->async_expr
		    = gfc_get_constant_expr (BT_INTEGER,
					     gfc_default_integer_kind,
					     &gfc_current_locus);
		  mpz_set_si (c->async_expr->value.integer, GOMP_ASYNC_NOVAL);
		  needs_space = true;
		}
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_AUTO)
	      && !c->par_auto
	      && gfc_match ("auto") == MATCH_YES)
	    {
	      c->par_auto = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_ATTACH)
	      && gfc_match ("attach ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_ATTACH, false,
					   allow_derived))
	    continue;
	  break;
	case 'c':
	  if ((mask & OMP_CLAUSE_CAPTURE)
	      && !c->capture
	      && gfc_match ("capture") == MATCH_YES)
	    {
	      c->capture = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_COLLAPSE)
	      && !c->collapse)
	    {
	      gfc_expr *cexpr = NULL;
	      match m = gfc_match ("collapse ( %e )", &cexpr);

	      if (m == MATCH_YES)
		{
		  int collapse;
		  if (gfc_extract_int (cexpr, &collapse, -1))
		    collapse = 1;
		  else if (collapse <= 0)
		    {
		      gfc_error_now ("COLLAPSE clause argument not"
				     " constant positive integer at %C");
		      collapse = 1;
		    }
		  c->collapse = collapse;
		  gfc_free_expr (cexpr);
		  continue;
		}
	    }
	  if ((mask & OMP_CLAUSE_COPY)
	      && gfc_match ("copy ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_TOFROM, true,
					   allow_derived))
	    continue;
	  if (mask & OMP_CLAUSE_COPYIN)
	    {
	      if (openacc)
		{
		  if (gfc_match ("copyin ( ") == MATCH_YES
		      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
						   OMP_MAP_TO, true,
						   allow_derived))
		    continue;
		}
	      else if (gfc_match_omp_variable_list ("copyin (",
						    &c->lists[OMP_LIST_COPYIN],
						    true) == MATCH_YES)
		continue;
	    }
	  if ((mask & OMP_CLAUSE_COPYOUT)
	      && gfc_match ("copyout ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FROM, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPYPRIVATE)
	      && gfc_match_omp_variable_list ("copyprivate (",
					      &c->lists[OMP_LIST_COPYPRIVATE],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_CREATE)
	      && gfc_match ("create ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_ALLOC, true, allow_derived))
	    continue;
	  break;
	case 'd':
	  if ((mask & OMP_CLAUSE_DEFAULT)
	      && c->default_sharing == OMP_DEFAULT_UNKNOWN)
	    {
	      if (gfc_match ("default ( none )") == MATCH_YES)
		c->default_sharing = OMP_DEFAULT_NONE;
	      else if (openacc)
		{
		  if (gfc_match ("default ( present )") == MATCH_YES)
		    c->default_sharing = OMP_DEFAULT_PRESENT;
		}
	      else
		{
		  if (gfc_match ("default ( firstprivate )") == MATCH_YES)
		    c->default_sharing = OMP_DEFAULT_FIRSTPRIVATE;
		  else if (gfc_match ("default ( private )") == MATCH_YES)
		    c->default_sharing = OMP_DEFAULT_PRIVATE;
		  else if (gfc_match ("default ( shared )") == MATCH_YES)
		    c->default_sharing = OMP_DEFAULT_SHARED;
		}
	      if (c->default_sharing != OMP_DEFAULT_UNKNOWN)
		continue;
	    }
	  if ((mask & OMP_CLAUSE_DEFAULTMAP)
	      && !c->defaultmap
	      && gfc_match ("defaultmap ( tofrom : scalar )") == MATCH_YES)
	    {
	      c->defaultmap = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_DELETE)
	      && gfc_match ("delete ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_RELEASE, true,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_DEPEND)
	      && gfc_match ("depend ( ") == MATCH_YES)
	    {
	      match m = MATCH_YES;
	      gfc_omp_depend_op depend_op = OMP_DEPEND_OUT;
	      if (gfc_match ("inout") == MATCH_YES)
		depend_op = OMP_DEPEND_INOUT;
	      else if (gfc_match ("in") == MATCH_YES)
		depend_op = OMP_DEPEND_IN;
	      else if (gfc_match ("out") == MATCH_YES)
		depend_op = OMP_DEPEND_OUT;
	      else if (!c->depend_source
		       && gfc_match ("source )") == MATCH_YES)
		{
		  c->depend_source = true;
		  continue;
		}
	      else if (gfc_match ("sink : ") == MATCH_YES)
		{
		  if (gfc_match_omp_depend_sink (&c->lists[OMP_LIST_DEPEND])
		      == MATCH_YES)
		    continue;
		  m = MATCH_NO;
		}
	      else
		m = MATCH_NO;
	      head = NULL;
	      if (m == MATCH_YES
		  && gfc_match_omp_variable_list (" : ",
						  &c->lists[OMP_LIST_DEPEND],
						  false, NULL, &head,
						  true) == MATCH_YES)
		{
		  gfc_omp_namelist *n;
		  for (n = *head; n; n = n->next)
		    n->u.depend_op = depend_op;
		  continue;
		}
	      else
		gfc_current_locus = old_loc;
	    }
	  if ((mask & OMP_CLAUSE_DETACH)
	      && !openacc
	      && !c->detach
	      && gfc_match_omp_detach (&c->detach) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_DETACH)
	      && openacc
	      && gfc_match ("detach ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_DETACH, false,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_DEVICE)
	      && !openacc
	      && c->device == NULL
	      && gfc_match ("device ( %e )", &c->device) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_DEVICE)
	      && openacc
	      && gfc_match ("device ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FORCE_TO, true,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_DEVICEPTR)
	      && gfc_match ("deviceptr ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FORCE_DEVICEPTR, false,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_DEVICE_TYPE)
	      && gfc_match ("device_type ( ") == MATCH_YES)
	    {
	      if (gfc_match ("host") == MATCH_YES)
		c->device_type = OMP_DEVICE_TYPE_HOST;
	      else if (gfc_match ("nohost") == MATCH_YES)
		c->device_type = OMP_DEVICE_TYPE_NOHOST;
	      else if (gfc_match ("any") == MATCH_YES)
		c->device_type = OMP_DEVICE_TYPE_ANY;
	      else
		{
		  gfc_error ("Expected HOST, NOHOST or ANY at %C");
		  break;
		}
	      if (gfc_match (" )") != MATCH_YES)
		break;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_DEVICE_RESIDENT)
	      && gfc_match_omp_variable_list
		   ("device_resident (",
		    &c->lists[OMP_LIST_DEVICE_RESIDENT], true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_DIST_SCHEDULE)
	      && c->dist_sched_kind == OMP_SCHED_NONE
	      && gfc_match ("dist_schedule ( static") == MATCH_YES)
	    {
	      match m = MATCH_NO;
	      c->dist_sched_kind = OMP_SCHED_STATIC;
	      m = gfc_match (" , %e )", &c->dist_chunk_size);
	      if (m != MATCH_YES)
		m = gfc_match_char (')');
	      if (m != MATCH_YES)
		{
		  c->dist_sched_kind = OMP_SCHED_NONE;
		  gfc_current_locus = old_loc;
		}
	      else
		continue;
	    }
	  break;
	case 'f':
	  if ((mask & OMP_CLAUSE_FINAL)
	      && c->final_expr == NULL
	      && gfc_match ("final ( %e )", &c->final_expr) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_FINALIZE)
	      && !c->finalize
	      && gfc_match ("finalize") == MATCH_YES)
	    {
	      c->finalize = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_FIRSTPRIVATE)
	      && gfc_match_omp_variable_list ("firstprivate (",
					      &c->lists[OMP_LIST_FIRSTPRIVATE],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_FROM)
	      && gfc_match_omp_variable_list ("from (",
					      &c->lists[OMP_LIST_FROM], false,
					      NULL, &head, true) == MATCH_YES)
	    continue;
	  break;
	case 'g':
	  if ((mask & OMP_CLAUSE_GANG)
	      && !c->gang
	      && gfc_match ("gang") == MATCH_YES)
	    {
	      c->gang = true;
	      match m = match_oacc_clause_gwv (c, GOMP_DIM_GANG);
	      if (m == MATCH_ERROR)
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      else if (m == MATCH_NO)
		needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_GRAINSIZE)
	      && c->grainsize == NULL
	      && gfc_match ("grainsize ( %e )", &c->grainsize) == MATCH_YES)
	    continue;
	  break;
	case 'h':
	  if ((mask & OMP_CLAUSE_HINT)
	      && c->hint == NULL
	      && gfc_match ("hint ( %e )", &c->hint) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_HOST_SELF)
	      && gfc_match ("host ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FORCE_FROM, true,
					   allow_derived))
	    continue;
	  break;
	case 'i':
	  if ((mask & OMP_CLAUSE_IF)
	      && c->if_expr == NULL
	      && gfc_match ("if ( ") == MATCH_YES)
	    {
	      if (!openacc)
		{
		  /* This should match the enum gfc_omp_if_kind order.  */
		  static const char *ifs[OMP_IF_LAST] = {
		    " cancel : %e )",
		    " parallel : %e )",
		    " simd : %e )",
		    " task : %e )",
		    " taskloop : %e )",
		    " target : %e )",
		    " target data : %e )",
		    " target update : %e )",
		    " target enter data : %e )",
		    " target exit data : %e )" };
		  int i;
		  for (i = 0; i < OMP_IF_LAST; i++)
		    if (c->if_exprs[i] == NULL
			&& gfc_match (ifs[i], &c->if_exprs[i]) == MATCH_YES)
		      break;
		  if (i < OMP_IF_LAST)
		    continue;
		}
	      if (gfc_match ("%e )", &c->if_expr) == MATCH_YES)
		continue;
	      gfc_current_locus = old_loc;
	    }
	  if ((mask & OMP_CLAUSE_IF_PRESENT)
	      && !c->if_present
	      && gfc_match ("if_present") == MATCH_YES)
	    {
	      c->if_present = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_IN_REDUCTION)
	      && gfc_match_omp_clause_reduction (pc, c, openacc,
						 allow_derived) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_INBRANCH)
	      && !c->inbranch
	      && !c->notinbranch
	      && gfc_match ("inbranch") == MATCH_YES)
	    {
	      c->inbranch = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_INDEPENDENT)
	      && !c->independent
	      && gfc_match ("independent") == MATCH_YES)
	    {
	      c->independent = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_IS_DEVICE_PTR)
	      && gfc_match_omp_variable_list
		   ("is_device_ptr (",
		    &c->lists[OMP_LIST_IS_DEVICE_PTR], false) == MATCH_YES)
	    continue;
	  break;
	case 'l':
	  if ((mask & OMP_CLAUSE_LASTPRIVATE)
	      && gfc_match ("lastprivate ( ") == MATCH_YES)
	    {
	      bool conditional = gfc_match ("conditional : ") == MATCH_YES;
	      head = NULL;
	      if (gfc_match_omp_variable_list ("",
					       &c->lists[OMP_LIST_LASTPRIVATE],
					       false, NULL, &head) == MATCH_YES)
		{
		  gfc_omp_namelist *n;
		  for (n = *head; n; n = n->next)
		    n->u.lastprivate_conditional = conditional;
		  continue;
		}
	      gfc_current_locus = old_loc;
	      break;
	    }
	  end_colon = false;
	  head = NULL;
	  if ((mask & OMP_CLAUSE_LINEAR)
	      && gfc_match ("linear (") == MATCH_YES)
	    {
	      gfc_omp_linear_op linear_op = OMP_LINEAR_DEFAULT;
	      gfc_expr *step = NULL;

	      if (gfc_match_omp_variable_list (" ref (",
					       &c->lists[OMP_LIST_LINEAR],
					       false, NULL, &head)
		  == MATCH_YES)
		linear_op = OMP_LINEAR_REF;
	      else if (gfc_match_omp_variable_list (" val (",
						    &c->lists[OMP_LIST_LINEAR],
						    false, NULL, &head)
		       == MATCH_YES)
		linear_op = OMP_LINEAR_VAL;
	      else if (gfc_match_omp_variable_list (" uval (",
						    &c->lists[OMP_LIST_LINEAR],
						    false, NULL, &head)
		       == MATCH_YES)
		linear_op = OMP_LINEAR_UVAL;
	      else if (gfc_match_omp_variable_list ("",
						    &c->lists[OMP_LIST_LINEAR],
						    false, &end_colon, &head)
		       == MATCH_YES)
		linear_op = OMP_LINEAR_DEFAULT;
	      else
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      if (linear_op != OMP_LINEAR_DEFAULT)
		{
		  if (gfc_match (" :") == MATCH_YES)
		    end_colon = true;
		  else if (gfc_match (" )") != MATCH_YES)
		    {
		      gfc_free_omp_namelist (*head);
		      gfc_current_locus = old_loc;
		      *head = NULL;
		      break;
		    }
		}
	      if (end_colon && gfc_match (" %e )", &step) != MATCH_YES)
		{
		  gfc_free_omp_namelist (*head);
		  gfc_current_locus = old_loc;
		  *head = NULL;
		  break;
		}
	      else if (!end_colon)
		{
		  step = gfc_get_constant_expr (BT_INTEGER,
						gfc_default_integer_kind,
						&old_loc);
		  mpz_set_si (step->value.integer, 1);
		}
	      (*head)->expr = step;
	      if (linear_op != OMP_LINEAR_DEFAULT)
		for (gfc_omp_namelist *n = *head; n; n = n->next)
		  n->u.linear_op = linear_op;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_LINK)
	      && openacc
	      && (gfc_match_oacc_clause_link ("link (",
					      &c->lists[OMP_LIST_LINK])
		  == MATCH_YES))
	    continue;
	  else if ((mask & OMP_CLAUSE_LINK)
		   && !openacc
		   && (gfc_match_omp_to_link ("link (",
					      &c->lists[OMP_LIST_LINK])
		       == MATCH_YES))
	    continue;
	  break;
	case 'm':
	  if ((mask & OMP_CLAUSE_MAP)
	      && gfc_match ("map ( ") == MATCH_YES)
	    {
	      locus old_loc2 = gfc_current_locus;
	      bool always = false;
	      gfc_omp_map_op map_op = OMP_MAP_TOFROM;
	      if (gfc_match ("always , ") == MATCH_YES)
		always = true;
	      if (gfc_match ("alloc : ") == MATCH_YES)
		map_op = OMP_MAP_ALLOC;
	      else if (gfc_match ("tofrom : ") == MATCH_YES)
		map_op = always ? OMP_MAP_ALWAYS_TOFROM : OMP_MAP_TOFROM;
	      else if (gfc_match ("to : ") == MATCH_YES)
		map_op = always ? OMP_MAP_ALWAYS_TO : OMP_MAP_TO;
	      else if (gfc_match ("from : ") == MATCH_YES)
		map_op = always ? OMP_MAP_ALWAYS_FROM : OMP_MAP_FROM;
	      else if (gfc_match ("release : ") == MATCH_YES)
		map_op = OMP_MAP_RELEASE;
	      else if (gfc_match ("delete : ") == MATCH_YES)
		map_op = OMP_MAP_DELETE;
	      else if (always)
		{
		  gfc_current_locus = old_loc2;
		  always = false;
		}
	      head = NULL;
	      if (gfc_match_omp_variable_list ("", &c->lists[OMP_LIST_MAP],
					       false, NULL, &head,
					       true, true) == MATCH_YES)
		{
		  gfc_omp_namelist *n;
		  for (n = *head; n; n = n->next)
		    n->u.map_op = map_op;
		  continue;
		}
	      else
		gfc_current_locus = old_loc;
	    }
	  if ((mask & OMP_CLAUSE_MERGEABLE) && !c->mergeable
	      && gfc_match ("mergeable") == MATCH_YES)
	    {
	      c->mergeable = needs_space = true;
	      continue;
	    }
	  break;
	case 'n':
	  if ((mask & OMP_CLAUSE_NO_CREATE)
	      && gfc_match ("no_create ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_IF_PRESENT, true,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_NOGROUP)
	      && !c->nogroup
	      && gfc_match ("nogroup") == MATCH_YES)
	    {
	      c->nogroup = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_NOTEMPORAL)
	      && gfc_match_omp_variable_list ("nontemporal (",
					      &c->lists[OMP_LIST_NONTEMPORAL],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_NOTINBRANCH)
	      && !c->notinbranch
	      && !c->inbranch
	      && gfc_match ("notinbranch") == MATCH_YES)
	    {
	      c->notinbranch = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_NOWAIT)
	      && !c->nowait
	      && gfc_match ("nowait") == MATCH_YES)
	    {
	      c->nowait = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_NUM_GANGS)
	      && c->num_gangs_expr == NULL
	      && gfc_match ("num_gangs ( %e )",
			    &c->num_gangs_expr) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_NUM_TASKS)
	      && c->num_tasks == NULL
	      && gfc_match ("num_tasks ( %e )", &c->num_tasks) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_NUM_TEAMS)
	      && c->num_teams == NULL
	      && gfc_match ("num_teams ( %e )", &c->num_teams) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_NUM_THREADS)
	      && c->num_threads == NULL
	      && (gfc_match ("num_threads ( %e )", &c->num_threads)
		  == MATCH_YES))
	    continue;
	  if ((mask & OMP_CLAUSE_NUM_WORKERS)
	      && c->num_workers_expr == NULL
	      && gfc_match ("num_workers ( %e )",
			    &c->num_workers_expr) == MATCH_YES)
	    continue;
	  break;
	case 'o':
	  if ((mask & OMP_CLAUSE_ORDER)
	      && !c->order_concurrent
	      && gfc_match ("order ( concurrent )") == MATCH_YES)
	    {
	      c->order_concurrent = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_ORDERED)
	      && !c->ordered
	      && gfc_match ("ordered") == MATCH_YES)
	    {
	      gfc_expr *cexpr = NULL;
	      match m = gfc_match (" ( %e )", &cexpr);

	      c->ordered = true;
	      if (m == MATCH_YES)
		{
		  int ordered = 0;
		  if (gfc_extract_int (cexpr, &ordered, -1))
		    ordered = 0;
		  else if (ordered <= 0)
		    {
		      gfc_error_now ("ORDERED clause argument not"
				     " constant positive integer at %C");
		      ordered = 0;
		    }
		  c->orderedc = ordered;
		  gfc_free_expr (cexpr);
		  continue;
		}

	      needs_space = true;
	      continue;
	    }
	  break;
	case 'p':
	  if ((mask & OMP_CLAUSE_COPY)
	      && gfc_match ("pcopy ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_TOFROM, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPYIN)
	      && gfc_match ("pcopyin ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_TO, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPYOUT)
	      && gfc_match ("pcopyout ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FROM, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_CREATE)
	      && gfc_match ("pcreate ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_ALLOC, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_PRESENT)
	      && gfc_match ("present ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FORCE_PRESENT, false,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPY)
	      && gfc_match ("present_or_copy ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_TOFROM, true,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPYIN)
	      && gfc_match ("present_or_copyin ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_TO, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_COPYOUT)
	      && gfc_match ("present_or_copyout ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FROM, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_CREATE)
	      && gfc_match ("present_or_create ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_ALLOC, true, allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_PRIORITY)
	      && c->priority == NULL
	      && gfc_match ("priority ( %e )", &c->priority) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_PRIVATE)
	      && gfc_match_omp_variable_list ("private (",
					      &c->lists[OMP_LIST_PRIVATE],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_PROC_BIND)
	      && c->proc_bind == OMP_PROC_BIND_UNKNOWN)
	    {
	      if (gfc_match ("proc_bind ( master )") == MATCH_YES)
		c->proc_bind = OMP_PROC_BIND_MASTER;
	      else if (gfc_match ("proc_bind ( spread )") == MATCH_YES)
		c->proc_bind = OMP_PROC_BIND_SPREAD;
	      else if (gfc_match ("proc_bind ( close )") == MATCH_YES)
		c->proc_bind = OMP_PROC_BIND_CLOSE;
	      if (c->proc_bind != OMP_PROC_BIND_UNKNOWN)
		continue;
	    }
	  break;
	case 'r':
	  if ((mask & OMP_CLAUSE_ATOMIC)
	      && c->atomic_op == GFC_OMP_ATOMIC_UNSET
	      && gfc_match ("read") == MATCH_YES)
	    {
	      c->atomic_op = GFC_OMP_ATOMIC_READ;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_REDUCTION)
	      && gfc_match_omp_clause_reduction (pc, c, openacc,
						 allow_derived) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("relaxed") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_RELAXED;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("release") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_RELEASE;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("relaxed") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_RELAXED;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("release") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_RELEASE;
	      needs_space = true;
	      continue;
	    }
	  break;
	case 's':
	  if ((mask & OMP_CLAUSE_SAFELEN)
	      && c->safelen_expr == NULL
	      && gfc_match ("safelen ( %e )", &c->safelen_expr) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_SCHEDULE)
	      && c->sched_kind == OMP_SCHED_NONE
	      && gfc_match ("schedule ( ") == MATCH_YES)
	    {
	      int nmodifiers = 0;
	      locus old_loc2 = gfc_current_locus;
	      do
		{
		  if (gfc_match ("simd") == MATCH_YES)
		    {
		      c->sched_simd = true;
		      nmodifiers++;
		    }
		  else if (gfc_match ("monotonic") == MATCH_YES)
		    {
		      c->sched_monotonic = true;
		      nmodifiers++;
		    }
		  else if (gfc_match ("nonmonotonic") == MATCH_YES)
		    {
		      c->sched_nonmonotonic = true;
		      nmodifiers++;
		    }
		  else
		    {
		      if (nmodifiers)
			gfc_current_locus = old_loc2;
		      break;
		    }
		  if (nmodifiers == 1
		      && gfc_match (" , ") == MATCH_YES)
		    continue;
		  else if (gfc_match (" : ") == MATCH_YES)
		    break;
		  gfc_current_locus = old_loc2;
		  break;
		}
	      while (1);
	      if (gfc_match ("static") == MATCH_YES)
		c->sched_kind = OMP_SCHED_STATIC;
	      else if (gfc_match ("dynamic") == MATCH_YES)
		c->sched_kind = OMP_SCHED_DYNAMIC;
	      else if (gfc_match ("guided") == MATCH_YES)
		c->sched_kind = OMP_SCHED_GUIDED;
	      else if (gfc_match ("runtime") == MATCH_YES)
		c->sched_kind = OMP_SCHED_RUNTIME;
	      else if (gfc_match ("auto") == MATCH_YES)
		c->sched_kind = OMP_SCHED_AUTO;
	      if (c->sched_kind != OMP_SCHED_NONE)
		{
		  match m = MATCH_NO;
		  if (c->sched_kind != OMP_SCHED_RUNTIME
		      && c->sched_kind != OMP_SCHED_AUTO)
		    m = gfc_match (" , %e )", &c->chunk_size);
		  if (m != MATCH_YES)
		    m = gfc_match_char (')');
		  if (m != MATCH_YES)
		    c->sched_kind = OMP_SCHED_NONE;
		}
	      if (c->sched_kind != OMP_SCHED_NONE)
		continue;
	      else
		gfc_current_locus = old_loc;
	    }
	  if ((mask & OMP_CLAUSE_HOST_SELF)
	      && gfc_match ("self ( ") == MATCH_YES
	      && gfc_match_omp_map_clause (&c->lists[OMP_LIST_MAP],
					   OMP_MAP_FORCE_FROM, true,
					   allow_derived))
	    continue;
	  if ((mask & OMP_CLAUSE_SEQ)
	      && !c->seq
	      && gfc_match ("seq") == MATCH_YES)
	    {
	      c->seq = true;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_MEMORDER)
	      && c->memorder == OMP_MEMORDER_UNSET
	      && gfc_match ("seq_cst") == MATCH_YES)
	    {
	      c->memorder = OMP_MEMORDER_SEQ_CST;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_SHARED)
	      && gfc_match_omp_variable_list ("shared (",
					      &c->lists[OMP_LIST_SHARED],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_SIMDLEN)
	      && c->simdlen_expr == NULL
	      && gfc_match ("simdlen ( %e )", &c->simdlen_expr) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_SIMD)
	      && !c->simd
	      && gfc_match ("simd") == MATCH_YES)
	    {
	      c->simd = needs_space = true;
	      continue;
	    }
	  break;
	case 't':
	  if ((mask & OMP_CLAUSE_TASK_REDUCTION)
	      && gfc_match_omp_clause_reduction (pc, c, openacc,
						 allow_derived) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_THREAD_LIMIT)
	      && c->thread_limit == NULL
	      && gfc_match ("thread_limit ( %e )",
			    &c->thread_limit) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_THREADS)
	      && !c->threads
	      && gfc_match ("threads") == MATCH_YES)
	    {
	      c->threads = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_TILE)
	      && !c->tile_list
	      && match_oacc_expr_list ("tile (", &c->tile_list,
				       true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_TO) && (mask & OMP_CLAUSE_LINK))
	    {
	      if (gfc_match_omp_to_link ("to (", &c->lists[OMP_LIST_TO])
		  == MATCH_YES)
		continue;
	    }
	  else if ((mask & OMP_CLAUSE_TO)
	      && gfc_match_omp_variable_list ("to (",
					      &c->lists[OMP_LIST_TO], false,
					      NULL, &head, true) == MATCH_YES)
	    continue;
	  break;
	case 'u':
	  if ((mask & OMP_CLAUSE_UNIFORM)
	      && gfc_match_omp_variable_list ("uniform (",
					      &c->lists[OMP_LIST_UNIFORM],
					      false) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_UNTIED)
	      && !c->untied
	      && gfc_match ("untied") == MATCH_YES)
	    {
	      c->untied = needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_ATOMIC)
	      && c->atomic_op == GFC_OMP_ATOMIC_UNSET
	      && gfc_match ("update") == MATCH_YES)
	    {
	      c->atomic_op = GFC_OMP_ATOMIC_UPDATE;
	      needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_USE_DEVICE)
	      && gfc_match_omp_variable_list ("use_device (",
					      &c->lists[OMP_LIST_USE_DEVICE],
					      true) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_USE_DEVICE_PTR)
	      && gfc_match_omp_variable_list
		   ("use_device_ptr (",
		    &c->lists[OMP_LIST_USE_DEVICE_PTR], false) == MATCH_YES)
	    continue;
	  if ((mask & OMP_CLAUSE_USE_DEVICE_ADDR)
	      && gfc_match_omp_variable_list
		   ("use_device_addr (",
		    &c->lists[OMP_LIST_USE_DEVICE_ADDR], false) == MATCH_YES)
	    continue;
	  break;
	case 'v':
	  /* VECTOR_LENGTH must be matched before VECTOR, because the latter
	     doesn't unconditionally match '('.  */
	  if ((mask & OMP_CLAUSE_VECTOR_LENGTH)
	      && c->vector_length_expr == NULL
	      && (gfc_match ("vector_length ( %e )", &c->vector_length_expr)
		  == MATCH_YES))
	    continue;
	  if ((mask & OMP_CLAUSE_VECTOR)
	      && !c->vector
	      && gfc_match ("vector") == MATCH_YES)
	    {
	      c->vector = true;
	      match m = match_oacc_clause_gwv (c, GOMP_DIM_VECTOR);
	      if (m == MATCH_ERROR)
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      if (m == MATCH_NO)
		needs_space = true;
	      continue;
	    }
	  break;
	case 'w':
	  if ((mask & OMP_CLAUSE_WAIT)
	      && gfc_match ("wait") == MATCH_YES)
	    {
	      match m = match_oacc_expr_list (" (", &c->wait_list, false);
	      if (m == MATCH_ERROR)
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      else if (m == MATCH_NO)
		{
		  gfc_expr *expr
		    = gfc_get_constant_expr (BT_INTEGER,
					     gfc_default_integer_kind,
					     &gfc_current_locus);
		  mpz_set_si (expr->value.integer, GOMP_ASYNC_NOVAL);
		  gfc_expr_list **expr_list = &c->wait_list;
		  while (*expr_list)
		    expr_list = &(*expr_list)->next;
		  *expr_list = gfc_get_expr_list ();
		  (*expr_list)->expr = expr;
		  needs_space = true;
		}
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_WORKER)
	      && !c->worker
	      && gfc_match ("worker") == MATCH_YES)
	    {
	      c->worker = true;
	      match m = match_oacc_clause_gwv (c, GOMP_DIM_WORKER);
	      if (m == MATCH_ERROR)
		{
		  gfc_current_locus = old_loc;
		  break;
		}
	      else if (m == MATCH_NO)
		needs_space = true;
	      continue;
	    }
	  if ((mask & OMP_CLAUSE_ATOMIC)
	      && c->atomic_op == GFC_OMP_ATOMIC_UNSET
	      && gfc_match ("write") == MATCH_YES)
	    {
	      c->atomic_op = GFC_OMP_ATOMIC_WRITE;
	      needs_space = true;
	      continue;
	    }
	  break;
	}
      break;
    }

  if (gfc_match_omp_eos () != MATCH_YES)
    {
      if (!gfc_error_flag_test ())
	gfc_error ("Failed to match clause at %C");
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }

  *cp = c;
  return MATCH_YES;
}


#define OACC_PARALLEL_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_NUM_GANGS	      \
   | OMP_CLAUSE_NUM_WORKERS | OMP_CLAUSE_VECTOR_LENGTH | OMP_CLAUSE_REDUCTION \
   | OMP_CLAUSE_COPY | OMP_CLAUSE_COPYIN | OMP_CLAUSE_COPYOUT		      \
   | OMP_CLAUSE_CREATE | OMP_CLAUSE_NO_CREATE | OMP_CLAUSE_PRESENT	      \
   | OMP_CLAUSE_DEVICEPTR | OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE      \
   | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_WAIT | OMP_CLAUSE_ATTACH)
#define OACC_KERNELS_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_NUM_GANGS	      \
   | OMP_CLAUSE_NUM_WORKERS | OMP_CLAUSE_VECTOR_LENGTH | OMP_CLAUSE_DEVICEPTR \
   | OMP_CLAUSE_COPY | OMP_CLAUSE_COPYIN | OMP_CLAUSE_COPYOUT		      \
   | OMP_CLAUSE_CREATE | OMP_CLAUSE_NO_CREATE | OMP_CLAUSE_PRESENT	      \
   | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_WAIT | OMP_CLAUSE_ATTACH)
#define OACC_SERIAL_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_REDUCTION	      \
   | OMP_CLAUSE_COPY | OMP_CLAUSE_COPYIN | OMP_CLAUSE_COPYOUT		      \
   | OMP_CLAUSE_CREATE | OMP_CLAUSE_NO_CREATE | OMP_CLAUSE_PRESENT	      \
   | OMP_CLAUSE_DEVICEPTR | OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE      \
   | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_WAIT | OMP_CLAUSE_ATTACH)
#define OACC_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_DEVICEPTR  | OMP_CLAUSE_COPY	      \
   | OMP_CLAUSE_COPYIN | OMP_CLAUSE_COPYOUT | OMP_CLAUSE_CREATE		      \
   | OMP_CLAUSE_NO_CREATE | OMP_CLAUSE_PRESENT | OMP_CLAUSE_ATTACH)
#define OACC_LOOP_CLAUSES \
  (omp_mask (OMP_CLAUSE_COLLAPSE) | OMP_CLAUSE_GANG | OMP_CLAUSE_WORKER	      \
   | OMP_CLAUSE_VECTOR | OMP_CLAUSE_SEQ | OMP_CLAUSE_INDEPENDENT	      \
   | OMP_CLAUSE_PRIVATE | OMP_CLAUSE_REDUCTION | OMP_CLAUSE_AUTO	      \
   | OMP_CLAUSE_TILE)
#define OACC_PARALLEL_LOOP_CLAUSES \
  (OACC_LOOP_CLAUSES | OACC_PARALLEL_CLAUSES)
#define OACC_KERNELS_LOOP_CLAUSES \
  (OACC_LOOP_CLAUSES | OACC_KERNELS_CLAUSES)
#define OACC_SERIAL_LOOP_CLAUSES \
  (OACC_LOOP_CLAUSES | OACC_SERIAL_CLAUSES)
#define OACC_HOST_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_USE_DEVICE)					      \
   | OMP_CLAUSE_IF							      \
   | OMP_CLAUSE_IF_PRESENT)
#define OACC_DECLARE_CLAUSES \
  (omp_mask (OMP_CLAUSE_COPY) | OMP_CLAUSE_COPYIN | OMP_CLAUSE_COPYOUT	      \
   | OMP_CLAUSE_CREATE | OMP_CLAUSE_DEVICEPTR | OMP_CLAUSE_DEVICE_RESIDENT    \
   | OMP_CLAUSE_PRESENT			      \
   | OMP_CLAUSE_LINK)
#define OACC_UPDATE_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_HOST_SELF	      \
   | OMP_CLAUSE_DEVICE | OMP_CLAUSE_WAIT | OMP_CLAUSE_IF_PRESENT)
#define OACC_ENTER_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_WAIT	      \
   | OMP_CLAUSE_COPYIN | OMP_CLAUSE_CREATE | OMP_CLAUSE_ATTACH)
#define OACC_EXIT_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_IF) | OMP_CLAUSE_ASYNC | OMP_CLAUSE_WAIT	      \
   | OMP_CLAUSE_COPYOUT | OMP_CLAUSE_DELETE | OMP_CLAUSE_FINALIZE	      \
   | OMP_CLAUSE_DETACH)
#define OACC_WAIT_CLAUSES \
  omp_mask (OMP_CLAUSE_ASYNC)
#define OACC_ROUTINE_CLAUSES \
  (omp_mask (OMP_CLAUSE_GANG) | OMP_CLAUSE_WORKER | OMP_CLAUSE_VECTOR	      \
   | OMP_CLAUSE_SEQ)


static match
match_acc (gfc_exec_op op, const omp_mask mask)
{
  gfc_omp_clauses *c;
  if (gfc_match_omp_clauses (&c, mask, false, false, true) != MATCH_YES)
    return MATCH_ERROR;
  new_st.op = op;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}

match
gfc_match_oacc_parallel_loop (void)
{
  return match_acc (EXEC_OACC_PARALLEL_LOOP, OACC_PARALLEL_LOOP_CLAUSES);
}


match
gfc_match_oacc_parallel (void)
{
  return match_acc (EXEC_OACC_PARALLEL, OACC_PARALLEL_CLAUSES);
}


match
gfc_match_oacc_kernels_loop (void)
{
  return match_acc (EXEC_OACC_KERNELS_LOOP, OACC_KERNELS_LOOP_CLAUSES);
}


match
gfc_match_oacc_kernels (void)
{
  return match_acc (EXEC_OACC_KERNELS, OACC_KERNELS_CLAUSES);
}


match
gfc_match_oacc_serial_loop (void)
{
  return match_acc (EXEC_OACC_SERIAL_LOOP, OACC_SERIAL_LOOP_CLAUSES);
}


match
gfc_match_oacc_serial (void)
{
  return match_acc (EXEC_OACC_SERIAL, OACC_SERIAL_CLAUSES);
}


match
gfc_match_oacc_data (void)
{
  return match_acc (EXEC_OACC_DATA, OACC_DATA_CLAUSES);
}


match
gfc_match_oacc_host_data (void)
{
  return match_acc (EXEC_OACC_HOST_DATA, OACC_HOST_DATA_CLAUSES);
}


match
gfc_match_oacc_loop (void)
{
  return match_acc (EXEC_OACC_LOOP, OACC_LOOP_CLAUSES);
}


match
gfc_match_oacc_declare (void)
{
  gfc_omp_clauses *c;
  gfc_omp_namelist *n;
  gfc_namespace *ns = gfc_current_ns;
  gfc_oacc_declare *new_oc;
  bool module_var = false;
  locus where = gfc_current_locus;

  if (gfc_match_omp_clauses (&c, OACC_DECLARE_CLAUSES, false, false, true)
      != MATCH_YES)
    return MATCH_ERROR;

  for (n = c->lists[OMP_LIST_DEVICE_RESIDENT]; n != NULL; n = n->next)
    n->sym->attr.oacc_declare_device_resident = 1;

  for (n = c->lists[OMP_LIST_LINK]; n != NULL; n = n->next)
    n->sym->attr.oacc_declare_link = 1;

  for (n = c->lists[OMP_LIST_MAP]; n != NULL; n = n->next)
    {
      gfc_symbol *s = n->sym;

      if (gfc_current_ns->proc_name
	  && gfc_current_ns->proc_name->attr.flavor == FL_MODULE)
	{
	  if (n->u.map_op != OMP_MAP_ALLOC && n->u.map_op != OMP_MAP_TO)
	    {
	      gfc_error ("Invalid clause in module with !$ACC DECLARE at %L",
			 &where);
	      return MATCH_ERROR;
	    }

	  module_var = true;
	}

      if (s->attr.use_assoc)
	{
	  gfc_error ("Variable is USE-associated with !$ACC DECLARE at %L",
		     &where);
	  return MATCH_ERROR;
	}

      if ((s->result == s && s->ns->contained != gfc_current_ns)
	  || ((s->attr.flavor == FL_UNKNOWN || s->attr.flavor == FL_VARIABLE)
	      && s->ns != gfc_current_ns))
	{
	  gfc_error ("Variable %qs shall be declared in the same scoping unit "
		     "as !$ACC DECLARE at %L", s->name, &where);
	  return MATCH_ERROR;
	}

      if ((s->attr.dimension || s->attr.codimension)
	  && s->attr.dummy && s->as->type != AS_EXPLICIT)
	{
	  gfc_error ("Assumed-size dummy array with !$ACC DECLARE at %L",
		     &where);
	  return MATCH_ERROR;
	}

      switch (n->u.map_op)
	{
	  case OMP_MAP_FORCE_ALLOC:
	  case OMP_MAP_ALLOC:
	    s->attr.oacc_declare_create = 1;
	    break;

	  case OMP_MAP_FORCE_TO:
	  case OMP_MAP_TO:
	    s->attr.oacc_declare_copyin = 1;
	    break;

	  case OMP_MAP_FORCE_DEVICEPTR:
	    s->attr.oacc_declare_deviceptr = 1;
	    break;

	  default:
	    break;
	}
    }

  new_oc = gfc_get_oacc_declare ();
  new_oc->next = ns->oacc_declare;
  new_oc->module_var = module_var;
  new_oc->clauses = c;
  new_oc->loc = gfc_current_locus;
  ns->oacc_declare = new_oc;

  return MATCH_YES;
}


match
gfc_match_oacc_update (void)
{
  gfc_omp_clauses *c;
  locus here = gfc_current_locus;

  if (gfc_match_omp_clauses (&c, OACC_UPDATE_CLAUSES, false, false, true)
      != MATCH_YES)
    return MATCH_ERROR;

  if (!c->lists[OMP_LIST_MAP])
    {
      gfc_error ("%<acc update%> must contain at least one "
		 "%<device%> or %<host%> or %<self%> clause at %L", &here);
      return MATCH_ERROR;
    }

  new_st.op = EXEC_OACC_UPDATE;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_oacc_enter_data (void)
{
  return match_acc (EXEC_OACC_ENTER_DATA, OACC_ENTER_DATA_CLAUSES);
}


match
gfc_match_oacc_exit_data (void)
{
  return match_acc (EXEC_OACC_EXIT_DATA, OACC_EXIT_DATA_CLAUSES);
}


match
gfc_match_oacc_wait (void)
{
  gfc_omp_clauses *c = gfc_get_omp_clauses ();
  gfc_expr_list *wait_list = NULL, *el;
  bool space = true;
  match m;

  m = match_oacc_expr_list (" (", &wait_list, true);
  if (m == MATCH_ERROR)
    return m;
  else if (m == MATCH_YES)
    space = false;

  if (gfc_match_omp_clauses (&c, OACC_WAIT_CLAUSES, space, space, true)
      == MATCH_ERROR)
    return MATCH_ERROR;

  if (wait_list)
    for (el = wait_list; el; el = el->next)
      {
	if (el->expr == NULL)
	  {
	    gfc_error ("Invalid argument to !$ACC WAIT at %C");
	    return MATCH_ERROR;
	  }

	if (!gfc_resolve_expr (el->expr)
	    || el->expr->ts.type != BT_INTEGER || el->expr->rank != 0)
	  {
	    gfc_error ("WAIT clause at %L requires a scalar INTEGER expression",
		       &el->expr->where);

	    return MATCH_ERROR;
	  }
      }
  c->wait_list = wait_list;
  new_st.op = EXEC_OACC_WAIT;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_oacc_cache (void)
{
  gfc_omp_clauses *c = gfc_get_omp_clauses ();
  /* The OpenACC cache directive explicitly only allows "array elements or
     subarrays", which we're currently not checking here.  Either check this
     after the call of gfc_match_omp_variable_list, or add something like a
     only_sections variant next to its allow_sections parameter.  */
  match m = gfc_match_omp_variable_list (" (",
					 &c->lists[OMP_LIST_CACHE], true,
					 NULL, NULL, true);
  if (m != MATCH_YES)
    {
      gfc_free_omp_clauses(c);
      return m;
    }

  if (gfc_current_state() != COMP_DO 
      && gfc_current_state() != COMP_DO_CONCURRENT)
    {
      gfc_error ("ACC CACHE directive must be inside of loop %C");
      gfc_free_omp_clauses(c);
      return MATCH_ERROR;
    }

  new_st.op = EXEC_OACC_CACHE;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}

/* Determine the OpenACC 'routine' directive's level of parallelism.  */

static oacc_routine_lop
gfc_oacc_routine_lop (gfc_omp_clauses *clauses)
{
  oacc_routine_lop ret = OACC_ROUTINE_LOP_SEQ;

  if (clauses)
    {
      unsigned n_lop_clauses = 0;

      if (clauses->gang)
	{
	  ++n_lop_clauses;
	  ret = OACC_ROUTINE_LOP_GANG;
	}
      if (clauses->worker)
	{
	  ++n_lop_clauses;
	  ret = OACC_ROUTINE_LOP_WORKER;
	}
      if (clauses->vector)
	{
	  ++n_lop_clauses;
	  ret = OACC_ROUTINE_LOP_VECTOR;
	}
      if (clauses->seq)
	{
	  ++n_lop_clauses;
	  ret = OACC_ROUTINE_LOP_SEQ;
	}

      if (n_lop_clauses > 1)
	ret = OACC_ROUTINE_LOP_ERROR;
    }

  return ret;
}

match
gfc_match_oacc_routine (void)
{
  locus old_loc;
  match m;
  gfc_intrinsic_sym *isym = NULL;
  gfc_symbol *sym = NULL;
  gfc_omp_clauses *c = NULL;
  gfc_oacc_routine_name *n = NULL;
  oacc_routine_lop lop = OACC_ROUTINE_LOP_NONE;

  old_loc = gfc_current_locus;

  m = gfc_match (" (");

  if (gfc_current_ns->proc_name
      && gfc_current_ns->proc_name->attr.if_source == IFSRC_IFBODY
      && m == MATCH_YES)
    {
      gfc_error ("Only the !$ACC ROUTINE form without "
		 "list is allowed in interface block at %C");
      goto cleanup;
    }

  if (m == MATCH_YES)
    {
      char buffer[GFC_MAX_SYMBOL_LEN + 1];

      m = gfc_match_name (buffer);
      if (m == MATCH_YES)
	{
	  gfc_symtree *st = NULL;

	  /* First look for an intrinsic symbol.  */
	  isym = gfc_find_function (buffer);
	  if (!isym)
	    isym = gfc_find_subroutine (buffer);
	  /* If no intrinsic symbol found, search the current namespace.  */
	  if (!isym)
	    st = gfc_find_symtree (gfc_current_ns->sym_root, buffer);
	  if (st)
	    {
	      sym = st->n.sym;
	      /* If the name in a 'routine' directive refers to the containing
		 subroutine or function, then make sure that we'll later handle
		 this accordingly.  */
	      if (gfc_current_ns->proc_name != NULL
		  && strcmp (sym->name, gfc_current_ns->proc_name->name) == 0)
	        sym = NULL;
	    }

	  if (isym == NULL && st == NULL)
	    {
	      gfc_error ("Invalid NAME %qs in !$ACC ROUTINE ( NAME ) at %C",
			 buffer);
	      gfc_current_locus = old_loc;
	      return MATCH_ERROR;
	    }
	}
      else
        {
	  gfc_error ("Syntax error in !$ACC ROUTINE ( NAME ) at %C");
	  gfc_current_locus = old_loc;
	  return MATCH_ERROR;
	}

      if (gfc_match_char (')') != MATCH_YES)
	{
	  gfc_error ("Syntax error in !$ACC ROUTINE ( NAME ) at %C, expecting"
		     " ')' after NAME");
	  gfc_current_locus = old_loc;
	  return MATCH_ERROR;
	}
    }

  if (gfc_match_omp_eos () != MATCH_YES
      && (gfc_match_omp_clauses (&c, OACC_ROUTINE_CLAUSES, false, false, true)
	  != MATCH_YES))
    return MATCH_ERROR;

  lop = gfc_oacc_routine_lop (c);
  if (lop == OACC_ROUTINE_LOP_ERROR)
    {
      gfc_error ("Multiple loop axes specified for routine at %C");
      goto cleanup;
    }

  if (isym != NULL)
    {
      /* Diagnose any OpenACC 'routine' directive that doesn't match the
	 (implicit) one with a 'seq' clause.  */
      if (c && (c->gang || c->worker || c->vector))
	{
	  gfc_error ("Intrinsic symbol specified in !$ACC ROUTINE ( NAME )"
		     " at %C marked with incompatible GANG, WORKER, or VECTOR"
		     " clause");
	  goto cleanup;
	}
    }
  else if (sym != NULL)
    {
      bool add = true;

      /* For a repeated OpenACC 'routine' directive, diagnose if it doesn't
	 match the first one.  */
      for (gfc_oacc_routine_name *n_p = gfc_current_ns->oacc_routine_names;
	   n_p;
	   n_p = n_p->next)
	if (n_p->sym == sym)
	  {
	    add = false;
	    if (lop != gfc_oacc_routine_lop (n_p->clauses))
	      {
		gfc_error ("!$ACC ROUTINE already applied at %C");
		goto cleanup;
	      }
	  }

      if (add)
	{
	  sym->attr.oacc_routine_lop = lop;

	  n = gfc_get_oacc_routine_name ();
	  n->sym = sym;
	  n->clauses = c;
	  n->next = gfc_current_ns->oacc_routine_names;
	  n->loc = old_loc;
	  gfc_current_ns->oacc_routine_names = n;
	}
    }
  else if (gfc_current_ns->proc_name)
    {
      /* For a repeated OpenACC 'routine' directive, diagnose if it doesn't
	 match the first one.  */
      oacc_routine_lop lop_p = gfc_current_ns->proc_name->attr.oacc_routine_lop;
      if (lop_p != OACC_ROUTINE_LOP_NONE
	  && lop != lop_p)
	{
	  gfc_error ("!$ACC ROUTINE already applied at %C");
	  goto cleanup;
	}

      if (!gfc_add_omp_declare_target (&gfc_current_ns->proc_name->attr,
				       gfc_current_ns->proc_name->name,
				       &old_loc))
	goto cleanup;
      gfc_current_ns->proc_name->attr.oacc_routine_lop = lop;
    }
  else
    /* Something has gone wrong, possibly a syntax error.  */
    goto cleanup;

  if (gfc_pure (NULL) && c && (c->gang || c->worker || c->vector))
    {
      gfc_error ("!$ACC ROUTINE with GANG, WORKER, or VECTOR clause is not "
		 "permitted in PURE procedure at %C");
      goto cleanup;
    }


  if (n)
    n->clauses = c;
  else if (gfc_current_ns->oacc_routine)
    gfc_current_ns->oacc_routine_clauses = c;

  new_st.op = EXEC_OACC_ROUTINE;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;  

cleanup:
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}


#define OMP_PARALLEL_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_SHARED | OMP_CLAUSE_COPYIN | OMP_CLAUSE_REDUCTION	\
   | OMP_CLAUSE_IF | OMP_CLAUSE_NUM_THREADS | OMP_CLAUSE_DEFAULT	\
   | OMP_CLAUSE_PROC_BIND)
#define OMP_DECLARE_SIMD_CLAUSES \
  (omp_mask (OMP_CLAUSE_SIMDLEN) | OMP_CLAUSE_LINEAR			\
   | OMP_CLAUSE_UNIFORM	| OMP_CLAUSE_ALIGNED | OMP_CLAUSE_INBRANCH	\
   | OMP_CLAUSE_NOTINBRANCH)
#define OMP_DO_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_LASTPRIVATE | OMP_CLAUSE_REDUCTION			\
   | OMP_CLAUSE_SCHEDULE | OMP_CLAUSE_ORDERED | OMP_CLAUSE_COLLAPSE	\
   | OMP_CLAUSE_LINEAR | OMP_CLAUSE_ORDER)
#define OMP_SECTIONS_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_LASTPRIVATE | OMP_CLAUSE_REDUCTION)
#define OMP_SIMD_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_LASTPRIVATE		\
   | OMP_CLAUSE_REDUCTION | OMP_CLAUSE_COLLAPSE | OMP_CLAUSE_SAFELEN	\
   | OMP_CLAUSE_LINEAR | OMP_CLAUSE_ALIGNED | OMP_CLAUSE_SIMDLEN	\
   | OMP_CLAUSE_IF | OMP_CLAUSE_ORDER | OMP_CLAUSE_NOTEMPORAL)
#define OMP_TASK_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_SHARED | OMP_CLAUSE_IF | OMP_CLAUSE_DEFAULT		\
   | OMP_CLAUSE_UNTIED | OMP_CLAUSE_FINAL | OMP_CLAUSE_MERGEABLE	\
   | OMP_CLAUSE_DEPEND | OMP_CLAUSE_PRIORITY | OMP_CLAUSE_IN_REDUCTION	\
   | OMP_CLAUSE_DETACH)
#define OMP_TASKLOOP_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_LASTPRIVATE | OMP_CLAUSE_SHARED | OMP_CLAUSE_IF		\
   | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_UNTIED | OMP_CLAUSE_FINAL		\
   | OMP_CLAUSE_MERGEABLE | OMP_CLAUSE_PRIORITY | OMP_CLAUSE_GRAINSIZE	\
   | OMP_CLAUSE_NUM_TASKS | OMP_CLAUSE_COLLAPSE | OMP_CLAUSE_NOGROUP	\
   | OMP_CLAUSE_REDUCTION | OMP_CLAUSE_IN_REDUCTION)
#define OMP_TARGET_CLAUSES \
  (omp_mask (OMP_CLAUSE_DEVICE) | OMP_CLAUSE_MAP | OMP_CLAUSE_IF	\
   | OMP_CLAUSE_DEPEND | OMP_CLAUSE_NOWAIT | OMP_CLAUSE_PRIVATE		\
   | OMP_CLAUSE_FIRSTPRIVATE | OMP_CLAUSE_DEFAULTMAP			\
   | OMP_CLAUSE_IS_DEVICE_PTR | OMP_CLAUSE_IN_REDUCTION)
#define OMP_TARGET_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_DEVICE) | OMP_CLAUSE_MAP | OMP_CLAUSE_IF	\
   | OMP_CLAUSE_USE_DEVICE_PTR | OMP_CLAUSE_USE_DEVICE_ADDR)
#define OMP_TARGET_ENTER_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_DEVICE) | OMP_CLAUSE_MAP | OMP_CLAUSE_IF	\
   | OMP_CLAUSE_DEPEND | OMP_CLAUSE_NOWAIT)
#define OMP_TARGET_EXIT_DATA_CLAUSES \
  (omp_mask (OMP_CLAUSE_DEVICE) | OMP_CLAUSE_MAP | OMP_CLAUSE_IF	\
   | OMP_CLAUSE_DEPEND | OMP_CLAUSE_NOWAIT)
#define OMP_TARGET_UPDATE_CLAUSES \
  (omp_mask (OMP_CLAUSE_DEVICE) | OMP_CLAUSE_IF | OMP_CLAUSE_TO		\
   | OMP_CLAUSE_FROM | OMP_CLAUSE_DEPEND | OMP_CLAUSE_NOWAIT)
#define OMP_TEAMS_CLAUSES \
  (omp_mask (OMP_CLAUSE_NUM_TEAMS) | OMP_CLAUSE_THREAD_LIMIT		\
   | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE	\
   | OMP_CLAUSE_SHARED | OMP_CLAUSE_REDUCTION)
#define OMP_DISTRIBUTE_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE		\
   | OMP_CLAUSE_LASTPRIVATE | OMP_CLAUSE_COLLAPSE | OMP_CLAUSE_DIST_SCHEDULE)
#define OMP_SINGLE_CLAUSES \
  (omp_mask (OMP_CLAUSE_PRIVATE) | OMP_CLAUSE_FIRSTPRIVATE)
#define OMP_ORDERED_CLAUSES \
  (omp_mask (OMP_CLAUSE_THREADS) | OMP_CLAUSE_SIMD)
#define OMP_DECLARE_TARGET_CLAUSES \
  (omp_mask (OMP_CLAUSE_TO) | OMP_CLAUSE_LINK | OMP_CLAUSE_DEVICE_TYPE)
#define OMP_ATOMIC_CLAUSES \
  (omp_mask (OMP_CLAUSE_ATOMIC) | OMP_CLAUSE_CAPTURE | OMP_CLAUSE_HINT	\
   | OMP_CLAUSE_MEMORDER)


static match
match_omp (gfc_exec_op op, const omp_mask mask)
{
  gfc_omp_clauses *c;
  if (gfc_match_omp_clauses (&c, mask) != MATCH_YES)
    return MATCH_ERROR;
  new_st.op = op;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_omp_critical (void)
{
  char n[GFC_MAX_SYMBOL_LEN+1];
  gfc_omp_clauses *c = NULL;

  if (gfc_match (" ( %n )", n) != MATCH_YES)
    n[0] = '\0';

  if (gfc_match_omp_clauses (&c, omp_mask (OMP_CLAUSE_HINT),
			     /* first = */ n[0] == '\0') != MATCH_YES)
    return MATCH_ERROR;

  new_st.op = EXEC_OMP_CRITICAL;
  new_st.ext.omp_clauses = c;
  if (n[0])
    c->critical_name = xstrdup (n);
  return MATCH_YES;
}


match
gfc_match_omp_end_critical (void)
{
  char n[GFC_MAX_SYMBOL_LEN+1];

  if (gfc_match (" ( %n )", n) != MATCH_YES)
    n[0] = '\0';
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP CRITICAL statement at %C");
      return MATCH_ERROR;
    }

  new_st.op = EXEC_OMP_END_CRITICAL;
  new_st.ext.omp_name = n[0] ? xstrdup (n) : NULL;
  return MATCH_YES;
}


match
gfc_match_omp_distribute (void)
{
  return match_omp (EXEC_OMP_DISTRIBUTE, OMP_DISTRIBUTE_CLAUSES);
}


match
gfc_match_omp_distribute_parallel_do (void)
{
  return match_omp (EXEC_OMP_DISTRIBUTE_PARALLEL_DO,
		    (OMP_DISTRIBUTE_CLAUSES | OMP_PARALLEL_CLAUSES
		     | OMP_DO_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_ORDERED))
		    & ~(omp_mask (OMP_CLAUSE_LINEAR)));
}


match
gfc_match_omp_distribute_parallel_do_simd (void)
{
  return match_omp (EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD,
		    (OMP_DISTRIBUTE_CLAUSES | OMP_PARALLEL_CLAUSES
		     | OMP_DO_CLAUSES | OMP_SIMD_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_ORDERED)));
}


match
gfc_match_omp_distribute_simd (void)
{
  return match_omp (EXEC_OMP_DISTRIBUTE_SIMD,
		    OMP_DISTRIBUTE_CLAUSES | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_do (void)
{
  return match_omp (EXEC_OMP_DO, OMP_DO_CLAUSES);
}


match
gfc_match_omp_do_simd (void)
{
  return match_omp (EXEC_OMP_DO_SIMD, OMP_DO_CLAUSES | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_flush (void)
{
  gfc_omp_namelist *list = NULL;
  gfc_omp_clauses *c = NULL;
  gfc_gobble_whitespace ();
  enum gfc_omp_memorder mo = OMP_MEMORDER_UNSET;
  if (gfc_match_omp_eos () == MATCH_NO && gfc_peek_ascii_char () != '(')
    {
      if (gfc_match ("acq_rel") == MATCH_YES)
	mo = OMP_MEMORDER_ACQ_REL;
      else if (gfc_match ("release") == MATCH_YES)
	mo = OMP_MEMORDER_RELEASE;
      else if (gfc_match ("acquire") == MATCH_YES)
	mo = OMP_MEMORDER_ACQUIRE;
      else
	{
	  gfc_error ("Expected AQC_REL, RELEASE, or ACQUIRE at %C");
	  return MATCH_ERROR;
	}
      c = gfc_get_omp_clauses ();
      c->memorder = mo;
    }
  gfc_match_omp_variable_list (" (", &list, true);
  if (list && mo != OMP_MEMORDER_UNSET)
    {
      gfc_error ("List specified together with memory order clause in FLUSH "
		 "directive at %C");
      gfc_free_omp_namelist (list);
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP FLUSH statement at %C");
      gfc_free_omp_namelist (list);
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_FLUSH;
  new_st.ext.omp_namelist = list;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_omp_declare_simd (void)
{
  locus where = gfc_current_locus;
  gfc_symbol *proc_name;
  gfc_omp_clauses *c;
  gfc_omp_declare_simd *ods;
  bool needs_space = false;

  switch (gfc_match (" ( %s ) ", &proc_name))
    {
    case MATCH_YES: break;
    case MATCH_NO: proc_name = NULL; needs_space = true; break;
    case MATCH_ERROR: return MATCH_ERROR;
    }

  if (gfc_match_omp_clauses (&c, OMP_DECLARE_SIMD_CLAUSES, true,
			     needs_space) != MATCH_YES)
    return MATCH_ERROR;

  if (gfc_current_ns->is_block_data)
    {
      gfc_free_omp_clauses (c);
      return MATCH_YES;
    }

  ods = gfc_get_omp_declare_simd ();
  ods->where = where;
  ods->proc_name = proc_name;
  ods->clauses = c;
  ods->next = gfc_current_ns->omp_declare_simd;
  gfc_current_ns->omp_declare_simd = ods;
  return MATCH_YES;
}


static bool
match_udr_expr (gfc_symtree *omp_sym1, gfc_symtree *omp_sym2)
{
  match m;
  locus old_loc = gfc_current_locus;
  char sname[GFC_MAX_SYMBOL_LEN + 1];
  gfc_symbol *sym;
  gfc_namespace *ns = gfc_current_ns;
  gfc_expr *lvalue = NULL, *rvalue = NULL;
  gfc_symtree *st;
  gfc_actual_arglist *arglist;

  m = gfc_match (" %v =", &lvalue);
  if (m != MATCH_YES)
    gfc_current_locus = old_loc;
  else
    {
      m = gfc_match (" %e )", &rvalue);
      if (m == MATCH_YES)
	{
	  ns->code = gfc_get_code (EXEC_ASSIGN);
	  ns->code->expr1 = lvalue;
	  ns->code->expr2 = rvalue;
	  ns->code->loc = old_loc;
	  return true;
	}

      gfc_current_locus = old_loc;
      gfc_free_expr (lvalue);
    }

  m = gfc_match (" %n", sname);
  if (m != MATCH_YES)
    return false;

  if (strcmp (sname, omp_sym1->name) == 0
      || strcmp (sname, omp_sym2->name) == 0)
    return false;

  gfc_current_ns = ns->parent;
  if (gfc_get_ha_sym_tree (sname, &st))
    return false;

  sym = st->n.sym;
  if (sym->attr.flavor != FL_PROCEDURE
      && sym->attr.flavor != FL_UNKNOWN)
    return false;

  if (!sym->attr.generic
      && !sym->attr.subroutine
      && !sym->attr.function)
    {
      if (!(sym->attr.external && !sym->attr.referenced))
	{
	  /* ...create a symbol in this scope...  */
	  if (sym->ns != gfc_current_ns
	      && gfc_get_sym_tree (sname, NULL, &st, false) == 1)
	    return false;

	  if (sym != st->n.sym)
	    sym = st->n.sym;
	}

      /* ...and then to try to make the symbol into a subroutine.  */
      if (!gfc_add_subroutine (&sym->attr, sym->name, NULL))
	return false;
    }

  gfc_set_sym_referenced (sym);
  gfc_gobble_whitespace ();
  if (gfc_peek_ascii_char () != '(')
    return false;

  gfc_current_ns = ns;
  m = gfc_match_actual_arglist (1, &arglist);
  if (m != MATCH_YES)
    return false;

  if (gfc_match_char (')') != MATCH_YES)
    return false;

  ns->code = gfc_get_code (EXEC_CALL);
  ns->code->symtree = st;
  ns->code->ext.actual = arglist;
  ns->code->loc = old_loc;
  return true;
}

static bool
gfc_omp_udr_predef (gfc_omp_reduction_op rop, const char *name,
		    gfc_typespec *ts, const char **n)
{
  if (!gfc_numeric_ts (ts) && ts->type != BT_LOGICAL)
    return false;

  switch (rop)
    {
    case OMP_REDUCTION_PLUS:
    case OMP_REDUCTION_MINUS:
    case OMP_REDUCTION_TIMES:
      return ts->type != BT_LOGICAL;
    case OMP_REDUCTION_AND:
    case OMP_REDUCTION_OR:
    case OMP_REDUCTION_EQV:
    case OMP_REDUCTION_NEQV:
      return ts->type == BT_LOGICAL;
    case OMP_REDUCTION_USER:
      if (name[0] != '.' && (ts->type == BT_INTEGER || ts->type == BT_REAL))
	{
	  gfc_symbol *sym;

	  gfc_find_symbol (name, NULL, 1, &sym);
	  if (sym != NULL)
	    {
	      if (sym->attr.intrinsic)
		*n = sym->name;
	      else if ((sym->attr.flavor != FL_UNKNOWN
			&& sym->attr.flavor != FL_PROCEDURE)
		       || sym->attr.external
		       || sym->attr.generic
		       || sym->attr.entry
		       || sym->attr.result
		       || sym->attr.dummy
		       || sym->attr.subroutine
		       || sym->attr.pointer
		       || sym->attr.target
		       || sym->attr.cray_pointer
		       || sym->attr.cray_pointee
		       || (sym->attr.proc != PROC_UNKNOWN
			   && sym->attr.proc != PROC_INTRINSIC)
		       || sym->attr.if_source != IFSRC_UNKNOWN
		       || sym == sym->ns->proc_name)
		*n = NULL;
	      else
		*n = sym->name;
	    }
	  else
	    *n = name;
	  if (*n
	      && (strcmp (*n, "max") == 0 || strcmp (*n, "min") == 0))
	    return true;
	  else if (*n
		   && ts->type == BT_INTEGER
		   && (strcmp (*n, "iand") == 0
		       || strcmp (*n, "ior") == 0
		       || strcmp (*n, "ieor") == 0))
	    return true;
	}
      break;
    default:
      break;
    }
  return false;
}

gfc_omp_udr *
gfc_omp_udr_find (gfc_symtree *st, gfc_typespec *ts)
{
  gfc_omp_udr *omp_udr;

  if (st == NULL)
    return NULL;

  for (omp_udr = st->n.omp_udr; omp_udr; omp_udr = omp_udr->next)
    if (omp_udr->ts.type == ts->type
	|| ((omp_udr->ts.type == BT_DERIVED || omp_udr->ts.type == BT_CLASS)
	    && (ts->type == BT_DERIVED || ts->type == BT_CLASS)))
      {
	if (omp_udr->ts.type == BT_DERIVED || omp_udr->ts.type == BT_CLASS)
	  {
	    if (strcmp (omp_udr->ts.u.derived->name, ts->u.derived->name) == 0)
	      return omp_udr;
	  }
	else if (omp_udr->ts.kind == ts->kind)
	  {
	    if (omp_udr->ts.type == BT_CHARACTER)
	      {
		if (omp_udr->ts.u.cl->length == NULL
		    || ts->u.cl->length == NULL)
		  return omp_udr;
		if (omp_udr->ts.u.cl->length->expr_type != EXPR_CONSTANT)
		  return omp_udr;
		if (ts->u.cl->length->expr_type != EXPR_CONSTANT)
		  return omp_udr;
		if (omp_udr->ts.u.cl->length->ts.type != BT_INTEGER)
		  return omp_udr;
		if (ts->u.cl->length->ts.type != BT_INTEGER)
		  return omp_udr;
		if (gfc_compare_expr (omp_udr->ts.u.cl->length,
				      ts->u.cl->length, INTRINSIC_EQ) != 0)
		  continue;
	      }
	    return omp_udr;
	  }
      }
  return NULL;
}

match
gfc_match_omp_declare_reduction (void)
{
  match m;
  gfc_intrinsic_op op;
  char name[GFC_MAX_SYMBOL_LEN + 3];
  auto_vec<gfc_typespec, 5> tss;
  gfc_typespec ts;
  unsigned int i;
  gfc_symtree *st;
  locus where = gfc_current_locus;
  locus end_loc = gfc_current_locus;
  bool end_loc_set = false;
  gfc_omp_reduction_op rop = OMP_REDUCTION_NONE;

  if (gfc_match_char ('(') != MATCH_YES)
    return MATCH_ERROR;

  m = gfc_match (" %o : ", &op);
  if (m == MATCH_ERROR)
    return MATCH_ERROR;
  if (m == MATCH_YES)
    {
      snprintf (name, sizeof name, "operator %s", gfc_op2string (op));
      rop = (gfc_omp_reduction_op) op;
    }
  else
    {
      m = gfc_match_defined_op_name (name + 1, 1);
      if (m == MATCH_ERROR)
	return MATCH_ERROR;
      if (m == MATCH_YES)
	{
	  name[0] = '.';
	  strcat (name, ".");
	  if (gfc_match (" : ") != MATCH_YES)
	    return MATCH_ERROR;
	}
      else
	{
	  if (gfc_match (" %n : ", name) != MATCH_YES)
	    return MATCH_ERROR;
	}
      rop = OMP_REDUCTION_USER;
    }

  m = gfc_match_type_spec (&ts);
  if (m != MATCH_YES)
    return MATCH_ERROR;
  /* Treat len=: the same as len=*.  */
  if (ts.type == BT_CHARACTER)
    ts.deferred = false;
  tss.safe_push (ts);

  while (gfc_match_char (',') == MATCH_YES)
    {
      m = gfc_match_type_spec (&ts);
      if (m != MATCH_YES)
	return MATCH_ERROR;
      tss.safe_push (ts);
    }
  if (gfc_match_char (':') != MATCH_YES)
    return MATCH_ERROR;

  st = gfc_find_symtree (gfc_current_ns->omp_udr_root, name);
  for (i = 0; i < tss.length (); i++)
    {
      gfc_symtree *omp_out, *omp_in;
      gfc_symtree *omp_priv = NULL, *omp_orig = NULL;
      gfc_namespace *combiner_ns, *initializer_ns = NULL;
      gfc_omp_udr *prev_udr, *omp_udr;
      const char *predef_name = NULL;

      omp_udr = gfc_get_omp_udr ();
      omp_udr->name = gfc_get_string ("%s", name);
      omp_udr->rop = rop;
      omp_udr->ts = tss[i];
      omp_udr->where = where;

      gfc_current_ns = combiner_ns = gfc_get_namespace (gfc_current_ns, 1);
      combiner_ns->proc_name = combiner_ns->parent->proc_name;

      gfc_get_sym_tree ("omp_out", combiner_ns, &omp_out, false);
      gfc_get_sym_tree ("omp_in", combiner_ns, &omp_in, false);
      combiner_ns->omp_udr_ns = 1;
      omp_out->n.sym->ts = tss[i];
      omp_in->n.sym->ts = tss[i];
      omp_out->n.sym->attr.omp_udr_artificial_var = 1;
      omp_in->n.sym->attr.omp_udr_artificial_var = 1;
      omp_out->n.sym->attr.flavor = FL_VARIABLE;
      omp_in->n.sym->attr.flavor = FL_VARIABLE;
      gfc_commit_symbols ();
      omp_udr->combiner_ns = combiner_ns;
      omp_udr->omp_out = omp_out->n.sym;
      omp_udr->omp_in = omp_in->n.sym;

      locus old_loc = gfc_current_locus;

      if (!match_udr_expr (omp_out, omp_in))
	{
	 syntax:
	  gfc_current_locus = old_loc;
	  gfc_current_ns = combiner_ns->parent;
	  gfc_undo_symbols ();
	  gfc_free_omp_udr (omp_udr);
	  return MATCH_ERROR;
	}

      if (gfc_match (" initializer ( ") == MATCH_YES)
	{
	  gfc_current_ns = combiner_ns->parent;
	  initializer_ns = gfc_get_namespace (gfc_current_ns, 1);
	  gfc_current_ns = initializer_ns;
	  initializer_ns->proc_name = initializer_ns->parent->proc_name;

	  gfc_get_sym_tree ("omp_priv", initializer_ns, &omp_priv, false);
	  gfc_get_sym_tree ("omp_orig", initializer_ns, &omp_orig, false);
	  initializer_ns->omp_udr_ns = 1;
	  omp_priv->n.sym->ts = tss[i];
	  omp_orig->n.sym->ts = tss[i];
	  omp_priv->n.sym->attr.omp_udr_artificial_var = 1;
	  omp_orig->n.sym->attr.omp_udr_artificial_var = 1;
	  omp_priv->n.sym->attr.flavor = FL_VARIABLE;
	  omp_orig->n.sym->attr.flavor = FL_VARIABLE;
	  gfc_commit_symbols ();
	  omp_udr->initializer_ns = initializer_ns;
	  omp_udr->omp_priv = omp_priv->n.sym;
	  omp_udr->omp_orig = omp_orig->n.sym;

	  if (!match_udr_expr (omp_priv, omp_orig))
	    goto syntax;
	}

      gfc_current_ns = combiner_ns->parent;
      if (!end_loc_set)
	{
	  end_loc_set = true;
	  end_loc = gfc_current_locus;
	}
      gfc_current_locus = old_loc;

      prev_udr = gfc_omp_udr_find (st, &tss[i]);
      if (gfc_omp_udr_predef (rop, name, &tss[i], &predef_name)
	  /* Don't error on !$omp declare reduction (min : integer : ...)
	     just yet, there could be integer :: min afterwards,
	     making it valid.  When the UDR is resolved, we'll get
	     to it again.  */
	  && (rop != OMP_REDUCTION_USER || name[0] == '.'))
	{
	  if (predef_name)
	    gfc_error_now ("Redefinition of predefined %s "
			   "!$OMP DECLARE REDUCTION at %L",
			   predef_name, &where);
	  else
	    gfc_error_now ("Redefinition of predefined "
			   "!$OMP DECLARE REDUCTION at %L", &where);
	}
      else if (prev_udr)
	{
	  gfc_error_now ("Redefinition of !$OMP DECLARE REDUCTION at %L",
			 &where);
	  gfc_error_now ("Previous !$OMP DECLARE REDUCTION at %L",
			 &prev_udr->where);
	}
      else if (st)
	{
	  omp_udr->next = st->n.omp_udr;
	  st->n.omp_udr = omp_udr;
	}
      else
	{
	  st = gfc_new_symtree (&gfc_current_ns->omp_udr_root, name);
	  st->n.omp_udr = omp_udr;
	}
    }

  if (end_loc_set)
    {
      gfc_current_locus = end_loc;
      if (gfc_match_omp_eos () != MATCH_YES)
	{
	  gfc_error ("Unexpected junk after !$OMP DECLARE REDUCTION at %C");
	  gfc_current_locus = where;
	  return MATCH_ERROR;
	}

      return MATCH_YES;
    }
  gfc_clear_error ();
  return MATCH_ERROR;
}


match
gfc_match_omp_declare_target (void)
{
  locus old_loc;
  match m;
  gfc_omp_clauses *c = NULL;
  int list;
  gfc_omp_namelist *n;
  gfc_symbol *s;

  old_loc = gfc_current_locus;

  if (gfc_current_ns->proc_name
      && gfc_match_omp_eos () == MATCH_YES)
    {
      if (!gfc_add_omp_declare_target (&gfc_current_ns->proc_name->attr,
				       gfc_current_ns->proc_name->name,
				       &old_loc))
	goto cleanup;
      return MATCH_YES;
    }

  if (gfc_current_ns->proc_name
      && gfc_current_ns->proc_name->attr.if_source == IFSRC_IFBODY)
    {
      gfc_error ("Only the !$OMP DECLARE TARGET form without "
		 "clauses is allowed in interface block at %C");
      goto cleanup;
    }

  m = gfc_match (" (");
  if (m == MATCH_YES)
    {
      c = gfc_get_omp_clauses ();
      gfc_current_locus = old_loc;
      m = gfc_match_omp_to_link (" (", &c->lists[OMP_LIST_TO]);
      if (m != MATCH_YES)
	goto syntax;
      if (gfc_match_omp_eos () != MATCH_YES)
	{
	  gfc_error ("Unexpected junk after !$OMP DECLARE TARGET at %C");
	  goto cleanup;
	}
    }
  else if (gfc_match_omp_clauses (&c, OMP_DECLARE_TARGET_CLAUSES) != MATCH_YES)
    return MATCH_ERROR;

  gfc_buffer_error (false);

  for (list = OMP_LIST_TO; list != OMP_LIST_NUM;
       list = (list == OMP_LIST_TO ? OMP_LIST_LINK : OMP_LIST_NUM))
    for (n = c->lists[list]; n; n = n->next)
      if (n->sym)
	n->sym->mark = 0;
      else if (n->u.common->head)
	n->u.common->head->mark = 0;

  for (list = OMP_LIST_TO; list != OMP_LIST_NUM;
       list = (list == OMP_LIST_TO ? OMP_LIST_LINK : OMP_LIST_NUM))
    for (n = c->lists[list]; n; n = n->next)
      if (n->sym)
	{
	  if (n->sym->attr.in_common)
	    gfc_error_now ("OMP DECLARE TARGET variable at %L is an "
			   "element of a COMMON block", &n->where);
	  else if (n->sym->attr.omp_declare_target
		   && n->sym->attr.omp_declare_target_link
		   && list != OMP_LIST_LINK)
	    gfc_error_now ("OMP DECLARE TARGET variable at %L previously "
			   "mentioned in LINK clause and later in TO clause",
			   &n->where);
	  else if (n->sym->attr.omp_declare_target
		   && !n->sym->attr.omp_declare_target_link
		   && list == OMP_LIST_LINK)
	    gfc_error_now ("OMP DECLARE TARGET variable at %L previously "
			   "mentioned in TO clause and later in LINK clause",
			   &n->where);
	  else if (n->sym->mark)
	    gfc_error_now ("Variable at %L mentioned multiple times in "
			   "clauses of the same OMP DECLARE TARGET directive",
			   &n->where);
	  else if (gfc_add_omp_declare_target (&n->sym->attr, n->sym->name,
					       &n->sym->declared_at))
	    {
	      if (list == OMP_LIST_LINK)
		gfc_add_omp_declare_target_link (&n->sym->attr, n->sym->name,
						 &n->sym->declared_at);
	    }
	  if (c->device_type != OMP_DEVICE_TYPE_UNSET)
	    {
	      if (n->sym->attr.omp_device_type != OMP_DEVICE_TYPE_UNSET
		  && n->sym->attr.omp_device_type != c->device_type)
		gfc_error_now ("List item %qs at %L set in previous OMP DECLARE "
			       "TARGET directive to a different DEVICE_TYPE",
			       n->sym->name, &n->where);
	      n->sym->attr.omp_device_type = c->device_type;
	    }
	  n->sym->mark = 1;
	}
      else if (n->u.common->omp_declare_target
	       && n->u.common->omp_declare_target_link
	       && list != OMP_LIST_LINK)
	gfc_error_now ("OMP DECLARE TARGET COMMON at %L previously "
		       "mentioned in LINK clause and later in TO clause",
		       &n->where);
      else if (n->u.common->omp_declare_target
	       && !n->u.common->omp_declare_target_link
	       && list == OMP_LIST_LINK)
	gfc_error_now ("OMP DECLARE TARGET COMMON at %L previously "
		       "mentioned in TO clause and later in LINK clause",
		       &n->where);
      else if (n->u.common->head && n->u.common->head->mark)
	gfc_error_now ("COMMON at %L mentioned multiple times in "
		       "clauses of the same OMP DECLARE TARGET directive",
		       &n->where);
      else
	{
	  n->u.common->omp_declare_target = 1;
	  n->u.common->omp_declare_target_link = (list == OMP_LIST_LINK);
	  if (n->u.common->omp_device_type != OMP_DEVICE_TYPE_UNSET
	      && n->u.common->omp_device_type != c->device_type)
	    gfc_error_now ("COMMON at %L set in previous OMP DECLARE "
			   "TARGET directive to a different DEVICE_TYPE",
			   &n->where);
	  n->u.common->omp_device_type = c->device_type;

	  for (s = n->u.common->head; s; s = s->common_next)
	    {
	      s->mark = 1;
	      if (gfc_add_omp_declare_target (&s->attr, s->name,
					      &s->declared_at))
		{
		  if (list == OMP_LIST_LINK)
		    gfc_add_omp_declare_target_link (&s->attr, s->name,
						     &s->declared_at);
		}
	      if (s->attr.omp_device_type != OMP_DEVICE_TYPE_UNSET
		  && s->attr.omp_device_type != c->device_type)
		gfc_error_now ("List item %qs at %L set in previous OMP DECLARE"
			       " TARGET directive to a different DEVICE_TYPE",
			       s->name, &n->where);
	      s->attr.omp_device_type = c->device_type;
	    }
	}
  if (c->device_type && !c->lists[OMP_LIST_TO] && !c->lists[OMP_LIST_LINK])
    gfc_warning_now (0, "OMP DECLARE TARGET directive at %L with only "
			"DEVICE_TYPE clause is ignored", &old_loc);

  gfc_buffer_error (true);

  if (c)
    gfc_free_omp_clauses (c);
  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in !$OMP DECLARE TARGET list at %C");

cleanup:
  gfc_current_locus = old_loc;
  if (c)
    gfc_free_omp_clauses (c);
  return MATCH_ERROR;
}


match
gfc_match_omp_threadprivate (void)
{
  locus old_loc;
  char n[GFC_MAX_SYMBOL_LEN+1];
  gfc_symbol *sym;
  match m;
  gfc_symtree *st;

  old_loc = gfc_current_locus;

  m = gfc_match (" (");
  if (m != MATCH_YES)
    return m;

  for (;;)
    {
      m = gfc_match_symbol (&sym, 0);
      switch (m)
	{
	case MATCH_YES:
	  if (sym->attr.in_common)
	    gfc_error_now ("Threadprivate variable at %C is an element of "
			   "a COMMON block");
	  else if (!gfc_add_threadprivate (&sym->attr, sym->name, &sym->declared_at))
	    goto cleanup;
	  goto next_item;
	case MATCH_NO:
	  break;
	case MATCH_ERROR:
	  goto cleanup;
	}

      m = gfc_match (" / %n /", n);
      if (m == MATCH_ERROR)
	goto cleanup;
      if (m == MATCH_NO || n[0] == '\0')
	goto syntax;

      st = gfc_find_symtree (gfc_current_ns->common_root, n);
      if (st == NULL)
	{
	  gfc_error ("COMMON block /%s/ not found at %C", n);
	  goto cleanup;
	}
      st->n.common->threadprivate = 1;
      for (sym = st->n.common->head; sym; sym = sym->common_next)
	if (!gfc_add_threadprivate (&sym->attr, sym->name, &sym->declared_at))
	  goto cleanup;

    next_item:
      if (gfc_match_char (')') == MATCH_YES)
	break;
      if (gfc_match_char (',') != MATCH_YES)
	goto syntax;
    }

  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after OMP THREADPRIVATE at %C");
      goto cleanup;
    }

  return MATCH_YES;

syntax:
  gfc_error ("Syntax error in !$OMP THREADPRIVATE list at %C");

cleanup:
  gfc_current_locus = old_loc;
  return MATCH_ERROR;
}


match
gfc_match_omp_parallel (void)
{
  return match_omp (EXEC_OMP_PARALLEL, OMP_PARALLEL_CLAUSES);
}


match
gfc_match_omp_parallel_do (void)
{
  return match_omp (EXEC_OMP_PARALLEL_DO,
		    OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES);
}


match
gfc_match_omp_parallel_do_simd (void)
{
  return match_omp (EXEC_OMP_PARALLEL_DO_SIMD,
		    OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_parallel_sections (void)
{
  return match_omp (EXEC_OMP_PARALLEL_SECTIONS,
		    OMP_PARALLEL_CLAUSES | OMP_SECTIONS_CLAUSES);
}


match
gfc_match_omp_parallel_workshare (void)
{
  return match_omp (EXEC_OMP_PARALLEL_WORKSHARE, OMP_PARALLEL_CLAUSES);
}

void
gfc_check_omp_requires (gfc_namespace *ns, int ref_omp_requires)
{
  if (ns->omp_target_seen
      && (ns->omp_requires & OMP_REQ_TARGET_MASK)
	 != (ref_omp_requires & OMP_REQ_TARGET_MASK))
    {
      gcc_assert (ns->proc_name);
      if ((ref_omp_requires & OMP_REQ_REVERSE_OFFLOAD)
	  && !(ns->omp_requires & OMP_REQ_REVERSE_OFFLOAD))
	gfc_error ("Program unit at %L has OpenMP device constructs/routines "
		   "but does not set !$OMP REQUIRES REVERSE_OFFSET but other "
		   "program units do", &ns->proc_name->declared_at);
      if ((ref_omp_requires & OMP_REQ_UNIFIED_ADDRESS)
	  && !(ns->omp_requires & OMP_REQ_UNIFIED_ADDRESS))
	gfc_error ("Program unit at %L has OpenMP device constructs/routines "
		   "but does not set !$OMP REQUIRES UNIFIED_ADDRESS but other "
		   "program units do", &ns->proc_name->declared_at);
      if ((ref_omp_requires & OMP_REQ_UNIFIED_SHARED_MEMORY)
	  && !(ns->omp_requires & OMP_REQ_UNIFIED_SHARED_MEMORY))
	gfc_error ("Program unit at %L has OpenMP device constructs/routines "
		   "but does not set !$OMP REQUIRES UNIFIED_SHARED_MEMORY but "
		   "other program units do", &ns->proc_name->declared_at);
    }
}

bool
gfc_omp_requires_add_clause (gfc_omp_requires_kind clause,
			     const char *clause_name, locus *loc,
			     const char *module_name)
{
  gfc_namespace *prog_unit = gfc_current_ns;
  while (prog_unit->parent)
    {
      if (gfc_state_stack->previous
	  && gfc_state_stack->previous->state == COMP_INTERFACE)
	break;
      prog_unit = prog_unit->parent;
    }

  /* Requires added after use.  */
  if (prog_unit->omp_target_seen
      && (clause & OMP_REQ_TARGET_MASK)
      && !(prog_unit->omp_requires & clause))
    {
      if (module_name)
	gfc_error ("!$OMP REQUIRES clause %qs specified via module %qs use "
		   "at %L comes after using a device construct/routine",
		   clause_name, module_name, loc);
      else
	gfc_error ("!$OMP REQUIRES clause %qs specified at %L comes after "
		   "using a device construct/routine", clause_name, loc);
      return false;
    }

  /* Overriding atomic_default_mem_order clause value.  */
  if ((clause & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
      && (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
      && (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
	 != (int) clause)
    {
      const char *other;
      if (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_SEQ_CST)
	other = "seq_cst";
      else if (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_ACQ_REL)
	other = "acq_rel";
      else if (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_RELAXED)
	other = "relaxed";
      else
	gcc_unreachable ();

      if (module_name)
	gfc_error ("!$OMP REQUIRES clause %<atomic_default_mem_order(%s)%> "
		   "specified via module %qs use at %L overrides a previous "
		   "%<atomic_default_mem_order(%s)%> (which might be through "
		   "using a module)", clause_name, module_name, loc, other);
      else
	gfc_error ("!$OMP REQUIRES clause %<atomic_default_mem_order(%s)%> "
		   "specified at %L overrides a previous "
		   "%<atomic_default_mem_order(%s)%> (which might be through "
		   "using a module)", clause_name, loc, other);
      return false;
    }

  /* Requires via module not at program-unit level and not repeating clause.  */
  if (prog_unit != gfc_current_ns && !(prog_unit->omp_requires & clause))
    {
      if (clause & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
	gfc_error ("!$OMP REQUIRES clause %<atomic_default_mem_order(%s)%> "
		   "specified via module %qs use at %L but same clause is "
		   "not specified for the program unit", clause_name,
		   module_name, loc);
      else
	gfc_error ("!$OMP REQUIRES clause %qs specified via module %qs use at "
		   "%L but same clause is not specified for the program unit",
		   clause_name, module_name, loc);
      return false;
    }

  if (!gfc_state_stack->previous
      || gfc_state_stack->previous->state != COMP_INTERFACE)
    prog_unit->omp_requires |= clause;
  return true;
}

match
gfc_match_omp_requires (void)
{
  static const char *clauses[] = {"reverse_offload",
				  "unified_address",
				  "unified_shared_memory",
				  "dynamic_allocators",
				  "atomic_default"};
  const char *clause = NULL;
  int requires_clauses = 0;
  bool first = true;
  locus old_loc;

  if (gfc_current_ns->parent
      && (!gfc_state_stack->previous
	  || gfc_state_stack->previous->state != COMP_INTERFACE))
    {
      gfc_error ("!$OMP REQUIRES at %C must appear in the specification part "
		 "of a program unit");
      return MATCH_ERROR;
    }

  while (true)
    {
      old_loc = gfc_current_locus;
      gfc_omp_requires_kind requires_clause;
      if ((first || gfc_match_char (',') != MATCH_YES)
	  && (first && gfc_match_space () != MATCH_YES))
	goto error;
      first = false;
      gfc_gobble_whitespace ();
      old_loc = gfc_current_locus;

      if (gfc_match_omp_eos () != MATCH_NO)
	break;
      if (gfc_match (clauses[0]) == MATCH_YES)
	{
	  clause = clauses[0];
	  requires_clause = OMP_REQ_REVERSE_OFFLOAD;
	  if (requires_clauses & OMP_REQ_REVERSE_OFFLOAD)
	    goto duplicate_clause;
	}
      else if (gfc_match (clauses[1]) == MATCH_YES)
	{
	  clause = clauses[1];
	  requires_clause = OMP_REQ_UNIFIED_ADDRESS;
	  if (requires_clauses & OMP_REQ_UNIFIED_ADDRESS)
	    goto duplicate_clause;
	}
      else if (gfc_match (clauses[2]) == MATCH_YES)
	{
	  clause = clauses[2];
	  requires_clause = OMP_REQ_UNIFIED_SHARED_MEMORY;
	  if (requires_clauses & OMP_REQ_UNIFIED_SHARED_MEMORY)
	    goto duplicate_clause;
	}
      else if (gfc_match (clauses[3]) == MATCH_YES)
	{
	  clause = clauses[3];
	  requires_clause = OMP_REQ_DYNAMIC_ALLOCATORS;
	  if (requires_clauses & OMP_REQ_DYNAMIC_ALLOCATORS)
	    goto duplicate_clause;
	}
      else if (gfc_match ("atomic_default_mem_order (") == MATCH_YES)
	{
	  clause = clauses[4];
	  if (requires_clauses & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
	    goto duplicate_clause;
	  if (gfc_match (" seq_cst )") == MATCH_YES)
	    {
	      clause = "seq_cst";
	      requires_clause = OMP_REQ_ATOMIC_MEM_ORDER_SEQ_CST;
	    }
	  else if (gfc_match (" acq_rel )") == MATCH_YES)
	    {
	      clause = "acq_rel";
	      requires_clause = OMP_REQ_ATOMIC_MEM_ORDER_ACQ_REL;
	    }
	  else if (gfc_match (" relaxed )") == MATCH_YES)
	    {
	      clause = "relaxed";
	      requires_clause = OMP_REQ_ATOMIC_MEM_ORDER_RELAXED;
	    }
	  else
	    {
	      gfc_error ("Expected SEQ_CST, ACQ_REL or RELAXED for "
			 "ATOMIC_DEFAULT_MEM_ORDER clause at %C");
	      goto error;
	    }
	}
      else
	goto error;

      if (requires_clause & ~OMP_REQ_ATOMIC_MEM_ORDER_MASK)
	gfc_error_now ("Sorry, %qs clause at %L on REQUIRES directive is not "
		       "yet supported", clause, &old_loc);
      if (!gfc_omp_requires_add_clause (requires_clause, clause, &old_loc, NULL))
	goto error;
      requires_clauses |= requires_clause;
    }

  if (requires_clauses == 0)
    {
      if (!gfc_error_flag_test ())
	gfc_error ("Clause expected at %C");
      goto error;
    }
  return MATCH_YES;

duplicate_clause:
  gfc_error ("%qs clause at %L specified more than once", clause, &old_loc);
error:
  if (!gfc_error_flag_test ())
    gfc_error ("Expected UNIFIED_ADDRESS, UNIFIED_SHARED_MEMORY, "
	       "DYNAMIC_ALLOCATORS, REVERSE_OFFLOAD, or "
	       "ATOMIC_DEFAULT_MEM_ORDER clause at %L", &old_loc);
  return MATCH_ERROR;
}


match
gfc_match_omp_scan (void)
{
  bool incl;
  gfc_omp_clauses *c = gfc_get_omp_clauses ();
  gfc_gobble_whitespace ();
  if ((incl = (gfc_match ("inclusive") == MATCH_YES))
      || gfc_match ("exclusive") == MATCH_YES)
    {
      if (gfc_match_omp_variable_list (" (", &c->lists[incl ? OMP_LIST_SCAN_IN
							    : OMP_LIST_SCAN_EX],
				       false) != MATCH_YES)
	{
	  gfc_free_omp_clauses (c);
	  return MATCH_ERROR;
	}
    }
  else
    {
      gfc_error ("Expected INCLUSIVE or EXCLUSIVE clause at %C");
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after !$OMP SCAN at %C");
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }

  new_st.op = EXEC_OMP_SCAN;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_omp_sections (void)
{
  return match_omp (EXEC_OMP_SECTIONS, OMP_SECTIONS_CLAUSES);
}


match
gfc_match_omp_simd (void)
{
  return match_omp (EXEC_OMP_SIMD, OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_single (void)
{
  return match_omp (EXEC_OMP_SINGLE, OMP_SINGLE_CLAUSES);
}


match
gfc_match_omp_target (void)
{
  return match_omp (EXEC_OMP_TARGET, OMP_TARGET_CLAUSES);
}


match
gfc_match_omp_target_data (void)
{
  return match_omp (EXEC_OMP_TARGET_DATA, OMP_TARGET_DATA_CLAUSES);
}


match
gfc_match_omp_target_enter_data (void)
{
  return match_omp (EXEC_OMP_TARGET_ENTER_DATA, OMP_TARGET_ENTER_DATA_CLAUSES);
}


match
gfc_match_omp_target_exit_data (void)
{
  return match_omp (EXEC_OMP_TARGET_EXIT_DATA, OMP_TARGET_EXIT_DATA_CLAUSES);
}


match
gfc_match_omp_target_parallel (void)
{
  return match_omp (EXEC_OMP_TARGET_PARALLEL,
		    (OMP_TARGET_CLAUSES | OMP_PARALLEL_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_COPYIN)));
}


match
gfc_match_omp_target_parallel_do (void)
{
  return match_omp (EXEC_OMP_TARGET_PARALLEL_DO,
		    (OMP_TARGET_CLAUSES | OMP_PARALLEL_CLAUSES
		     | OMP_DO_CLAUSES) & ~(omp_mask (OMP_CLAUSE_COPYIN)));
}


match
gfc_match_omp_target_parallel_do_simd (void)
{
  return match_omp (EXEC_OMP_TARGET_PARALLEL_DO_SIMD,
		    (OMP_TARGET_CLAUSES | OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES
		     | OMP_SIMD_CLAUSES) & ~(omp_mask (OMP_CLAUSE_COPYIN)));
}


match
gfc_match_omp_target_simd (void)
{
  return match_omp (EXEC_OMP_TARGET_SIMD,
		    OMP_TARGET_CLAUSES | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_target_teams (void)
{
  return match_omp (EXEC_OMP_TARGET_TEAMS,
		    OMP_TARGET_CLAUSES | OMP_TEAMS_CLAUSES);
}


match
gfc_match_omp_target_teams_distribute (void)
{
  return match_omp (EXEC_OMP_TARGET_TEAMS_DISTRIBUTE,
		    OMP_TARGET_CLAUSES | OMP_TEAMS_CLAUSES
		    | OMP_DISTRIBUTE_CLAUSES);
}


match
gfc_match_omp_target_teams_distribute_parallel_do (void)
{
  return match_omp (EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO,
		    (OMP_TARGET_CLAUSES | OMP_TEAMS_CLAUSES
		     | OMP_DISTRIBUTE_CLAUSES | OMP_PARALLEL_CLAUSES
		     | OMP_DO_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_ORDERED))
		    & ~(omp_mask (OMP_CLAUSE_LINEAR)));
}


match
gfc_match_omp_target_teams_distribute_parallel_do_simd (void)
{
  return match_omp (EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD,
		    (OMP_TARGET_CLAUSES | OMP_TEAMS_CLAUSES
		     | OMP_DISTRIBUTE_CLAUSES | OMP_PARALLEL_CLAUSES
		     | OMP_DO_CLAUSES | OMP_SIMD_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_ORDERED)));
}


match
gfc_match_omp_target_teams_distribute_simd (void)
{
  return match_omp (EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD,
		    OMP_TARGET_CLAUSES | OMP_TEAMS_CLAUSES
		    | OMP_DISTRIBUTE_CLAUSES | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_target_update (void)
{
  return match_omp (EXEC_OMP_TARGET_UPDATE, OMP_TARGET_UPDATE_CLAUSES);
}


match
gfc_match_omp_task (void)
{
  return match_omp (EXEC_OMP_TASK, OMP_TASK_CLAUSES);
}


match
gfc_match_omp_taskloop (void)
{
  return match_omp (EXEC_OMP_TASKLOOP, OMP_TASKLOOP_CLAUSES);
}


match
gfc_match_omp_taskloop_simd (void)
{
  return match_omp (EXEC_OMP_TASKLOOP_SIMD,
		    (OMP_TASKLOOP_CLAUSES | OMP_SIMD_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_REDUCTION)));
}


match
gfc_match_omp_taskwait (void)
{
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after TASKWAIT clause at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_TASKWAIT;
  new_st.ext.omp_clauses = NULL;
  return MATCH_YES;
}


match
gfc_match_omp_taskyield (void)
{
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after TASKYIELD clause at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_TASKYIELD;
  new_st.ext.omp_clauses = NULL;
  return MATCH_YES;
}


match
gfc_match_omp_teams (void)
{
  return match_omp (EXEC_OMP_TEAMS, OMP_TEAMS_CLAUSES);
}


match
gfc_match_omp_teams_distribute (void)
{
  return match_omp (EXEC_OMP_TEAMS_DISTRIBUTE,
		    OMP_TEAMS_CLAUSES | OMP_DISTRIBUTE_CLAUSES);
}


match
gfc_match_omp_teams_distribute_parallel_do (void)
{
  return match_omp (EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO,
		    (OMP_TEAMS_CLAUSES | OMP_DISTRIBUTE_CLAUSES
		     | OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES)
		    & ~(omp_mask (OMP_CLAUSE_ORDERED))
		    & ~(omp_mask (OMP_CLAUSE_LINEAR)));
}


match
gfc_match_omp_teams_distribute_parallel_do_simd (void)
{
  return match_omp (EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD,
		    (OMP_TEAMS_CLAUSES | OMP_DISTRIBUTE_CLAUSES
		     | OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES
		     | OMP_SIMD_CLAUSES) & ~(omp_mask (OMP_CLAUSE_ORDERED)));
}


match
gfc_match_omp_teams_distribute_simd (void)
{
  return match_omp (EXEC_OMP_TEAMS_DISTRIBUTE_SIMD,
		    OMP_TEAMS_CLAUSES | OMP_DISTRIBUTE_CLAUSES
		    | OMP_SIMD_CLAUSES);
}


match
gfc_match_omp_workshare (void)
{
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP WORKSHARE statement at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_WORKSHARE;
  new_st.ext.omp_clauses = gfc_get_omp_clauses ();
  return MATCH_YES;
}


match
gfc_match_omp_master (void)
{
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP MASTER statement at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_MASTER;
  new_st.ext.omp_clauses = NULL;
  return MATCH_YES;
}


match
gfc_match_omp_ordered (void)
{
  return match_omp (EXEC_OMP_ORDERED, OMP_ORDERED_CLAUSES);
}


match
gfc_match_omp_ordered_depend (void)
{
  return match_omp (EXEC_OMP_ORDERED, omp_mask (OMP_CLAUSE_DEPEND));
}


/* omp atomic [clause-list]
   - atomic-clause:  read | write | update
   - capture
   - memory-order-clause: seq_cst | acq_rel | release | acquire | relaxed
   - hint(hint-expr)
*/

match
gfc_match_omp_atomic (void)
{
  gfc_omp_clauses *c;
  locus loc = gfc_current_locus;

  if (gfc_match_omp_clauses (&c, OMP_ATOMIC_CLAUSES, true, true) != MATCH_YES)
    return MATCH_ERROR;

  if (c->capture && c->atomic_op != GFC_OMP_ATOMIC_UNSET)
    gfc_error ("OMP ATOMIC at %L with multiple atomic clauses", &loc);

  if (c->atomic_op == GFC_OMP_ATOMIC_UNSET)
    c->atomic_op = GFC_OMP_ATOMIC_UPDATE;

  if (c->memorder == OMP_MEMORDER_UNSET)
    {
      gfc_namespace *prog_unit = gfc_current_ns;
      while (prog_unit->parent)
	prog_unit = prog_unit->parent;
      switch (prog_unit->omp_requires & OMP_REQ_ATOMIC_MEM_ORDER_MASK)
	{
	case 0:
	case OMP_REQ_ATOMIC_MEM_ORDER_RELAXED:
	  c->memorder = OMP_MEMORDER_RELAXED;
	  break;
	case OMP_REQ_ATOMIC_MEM_ORDER_SEQ_CST:
	  c->memorder = OMP_MEMORDER_SEQ_CST;
	  break;
	case OMP_REQ_ATOMIC_MEM_ORDER_ACQ_REL:
	  if (c->capture)
	    c->memorder = OMP_MEMORDER_ACQ_REL;
	  else if (c->atomic_op == GFC_OMP_ATOMIC_READ)
	    c->memorder = OMP_MEMORDER_ACQUIRE;
	  else
	    c->memorder = OMP_MEMORDER_RELEASE;
	  break;
	default:
	  gcc_unreachable ();
	}
    }
  else
    switch (c->atomic_op)
      {
      case GFC_OMP_ATOMIC_READ:
	if (c->memorder == OMP_MEMORDER_ACQ_REL
	    || c->memorder == OMP_MEMORDER_RELEASE)
	  {
	    gfc_error ("!$OMP ATOMIC READ at %L incompatible with "
		       "ACQ_REL or RELEASE clauses", &loc);
	    c->memorder = OMP_MEMORDER_SEQ_CST;
	  }
	break;
      case GFC_OMP_ATOMIC_WRITE:
	if (c->memorder == OMP_MEMORDER_ACQ_REL
	    || c->memorder == OMP_MEMORDER_ACQUIRE)
	  {
	    gfc_error ("!$OMP ATOMIC WRITE at %L incompatible with "
		       "ACQ_REL or ACQUIRE clauses", &loc);
	    c->memorder = OMP_MEMORDER_SEQ_CST;
	  }
	break;
      case GFC_OMP_ATOMIC_UPDATE:
	if ((c->memorder == OMP_MEMORDER_ACQ_REL
	     || c->memorder == OMP_MEMORDER_ACQUIRE)
	    && !c->capture)
	  {
	    gfc_error ("!$OMP ATOMIC UPDATE at %L incompatible with "
		       "ACQ_REL or ACQUIRE clauses", &loc);
	    c->memorder = OMP_MEMORDER_SEQ_CST;
	  }
	break;
      default:
	break;
      }
  gfc_error_check ();
  new_st.ext.omp_clauses = c;
  new_st.op = EXEC_OMP_ATOMIC;
  return MATCH_YES;
}


/* acc atomic [ read | write | update | capture]  */

match
gfc_match_oacc_atomic (void)
{
  gfc_omp_clauses *c = gfc_get_omp_clauses ();
  c->atomic_op = GFC_OMP_ATOMIC_UPDATE;
  c->memorder = OMP_MEMORDER_RELAXED;
  gfc_gobble_whitespace ();
  if (gfc_match ("update") == MATCH_YES)
    ;
  else if (gfc_match ("read") == MATCH_YES)
    c->atomic_op = GFC_OMP_ATOMIC_READ;
  else if (gfc_match ("write") == MATCH_YES)
    c->atomic_op = GFC_OMP_ATOMIC_WRITE;
  else if (gfc_match ("capture") == MATCH_YES)
    c->capture = true;
  gfc_gobble_whitespace ();
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after !$ACC ATOMIC statement at %C");
      gfc_free_omp_clauses (c);
      return MATCH_ERROR;
    }
  new_st.ext.omp_clauses = c;
  new_st.op = EXEC_OACC_ATOMIC;
  return MATCH_YES;
}


match
gfc_match_omp_barrier (void)
{
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP BARRIER statement at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_BARRIER;
  new_st.ext.omp_clauses = NULL;
  return MATCH_YES;
}


match
gfc_match_omp_taskgroup (void)
{
  return match_omp (EXEC_OMP_TASKGROUP, OMP_CLAUSE_TASK_REDUCTION);
}


static enum gfc_omp_cancel_kind
gfc_match_omp_cancel_kind (void)
{
  if (gfc_match_space () != MATCH_YES)
    return OMP_CANCEL_UNKNOWN;
  if (gfc_match ("parallel") == MATCH_YES)
    return OMP_CANCEL_PARALLEL;
  if (gfc_match ("sections") == MATCH_YES)
    return OMP_CANCEL_SECTIONS;
  if (gfc_match ("do") == MATCH_YES)
    return OMP_CANCEL_DO;
  if (gfc_match ("taskgroup") == MATCH_YES)
    return OMP_CANCEL_TASKGROUP;
  return OMP_CANCEL_UNKNOWN;
}


match
gfc_match_omp_cancel (void)
{
  gfc_omp_clauses *c;
  enum gfc_omp_cancel_kind kind = gfc_match_omp_cancel_kind ();
  if (kind == OMP_CANCEL_UNKNOWN)
    return MATCH_ERROR;
  if (gfc_match_omp_clauses (&c, omp_mask (OMP_CLAUSE_IF), false) != MATCH_YES)
    return MATCH_ERROR;
  c->cancel = kind;
  new_st.op = EXEC_OMP_CANCEL;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_omp_cancellation_point (void)
{
  gfc_omp_clauses *c;
  enum gfc_omp_cancel_kind kind = gfc_match_omp_cancel_kind ();
  if (kind == OMP_CANCEL_UNKNOWN)
    return MATCH_ERROR;
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after $OMP CANCELLATION POINT statement "
		 "at %C");
      return MATCH_ERROR;
    }
  c = gfc_get_omp_clauses ();
  c->cancel = kind;
  new_st.op = EXEC_OMP_CANCELLATION_POINT;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


match
gfc_match_omp_end_nowait (void)
{
  bool nowait = false;
  if (gfc_match ("% nowait") == MATCH_YES)
    nowait = true;
  if (gfc_match_omp_eos () != MATCH_YES)
    {
      gfc_error ("Unexpected junk after NOWAIT clause at %C");
      return MATCH_ERROR;
    }
  new_st.op = EXEC_OMP_END_NOWAIT;
  new_st.ext.omp_bool = nowait;
  return MATCH_YES;
}


match
gfc_match_omp_end_single (void)
{
  gfc_omp_clauses *c;
  if (gfc_match ("% nowait") == MATCH_YES)
    {
      new_st.op = EXEC_OMP_END_NOWAIT;
      new_st.ext.omp_bool = true;
      return MATCH_YES;
    }
  if (gfc_match_omp_clauses (&c, omp_mask (OMP_CLAUSE_COPYPRIVATE))
      != MATCH_YES)
    return MATCH_ERROR;
  new_st.op = EXEC_OMP_END_SINGLE;
  new_st.ext.omp_clauses = c;
  return MATCH_YES;
}


static bool
oacc_is_loop (gfc_code *code)
{
  return code->op == EXEC_OACC_PARALLEL_LOOP
	 || code->op == EXEC_OACC_KERNELS_LOOP
	 || code->op == EXEC_OACC_SERIAL_LOOP
	 || code->op == EXEC_OACC_LOOP;
}

static void
resolve_scalar_int_expr (gfc_expr *expr, const char *clause)
{
  if (!gfc_resolve_expr (expr)
      || expr->ts.type != BT_INTEGER
      || expr->rank != 0)
    gfc_error ("%s clause at %L requires a scalar INTEGER expression",
	       clause, &expr->where);
}

static void
resolve_positive_int_expr (gfc_expr *expr, const char *clause)
{
  resolve_scalar_int_expr (expr, clause);
  if (expr->expr_type == EXPR_CONSTANT
      && expr->ts.type == BT_INTEGER
      && mpz_sgn (expr->value.integer) <= 0)
    gfc_warning (0, "INTEGER expression of %s clause at %L must be positive",
		 clause, &expr->where);
}

static void
resolve_nonnegative_int_expr (gfc_expr *expr, const char *clause)
{
  resolve_scalar_int_expr (expr, clause);
  if (expr->expr_type == EXPR_CONSTANT
      && expr->ts.type == BT_INTEGER
      && mpz_sgn (expr->value.integer) < 0)
    gfc_warning (0, "INTEGER expression of %s clause at %L must be "
		 "non-negative", clause, &expr->where);
}

/* Emits error when symbol is pointer, cray pointer or cray pointee
   of derived of polymorphic type.  */

static void
check_symbol_not_pointer (gfc_symbol *sym, locus loc, const char *name)
{
  if (sym->ts.type == BT_DERIVED && sym->attr.cray_pointer)
    gfc_error ("Cray pointer object %qs of derived type in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->ts.type == BT_DERIVED && sym->attr.cray_pointee)
    gfc_error ("Cray pointee object %qs of derived type in %s clause at %L",
	       sym->name, name, &loc);

  if ((sym->ts.type == BT_ASSUMED && sym->attr.pointer)
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.pointer))
    gfc_error ("POINTER object %qs of polymorphic type in %s clause at %L",
	       sym->name, name, &loc);
  if ((sym->ts.type == BT_ASSUMED && sym->attr.cray_pointer)
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.cray_pointer))
    gfc_error ("Cray pointer object %qs of polymorphic type in %s clause at %L",
	       sym->name, name, &loc);
  if ((sym->ts.type == BT_ASSUMED && sym->attr.cray_pointee)
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.cray_pointee))
    gfc_error ("Cray pointee object %qs of polymorphic type in %s clause at %L",
	       sym->name, name, &loc);
}

/* Emits error when symbol represents assumed size/rank array.  */

static void
check_array_not_assumed (gfc_symbol *sym, locus loc, const char *name)
{
  if (sym->as && sym->as->type == AS_ASSUMED_SIZE)
    gfc_error ("Assumed size array %qs in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->as && sym->as->type == AS_ASSUMED_RANK)
    gfc_error ("Assumed rank array %qs in %s clause at %L",
	       sym->name, name, &loc);
}

static void
resolve_oacc_data_clauses (gfc_symbol *sym, locus loc, const char *name)
{
  check_array_not_assumed (sym, loc, name);
}

static void
resolve_oacc_deviceptr_clause (gfc_symbol *sym, locus loc, const char *name)
{
  if (sym->attr.pointer
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.class_pointer))
    gfc_error ("POINTER object %qs in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->attr.cray_pointer
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.cray_pointer))
    gfc_error ("Cray pointer object %qs in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->attr.cray_pointee
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.cray_pointee))
    gfc_error ("Cray pointee object %qs in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->attr.allocatable
      || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
	  && CLASS_DATA (sym)->attr.allocatable))
    gfc_error ("ALLOCATABLE object %qs in %s clause at %L",
	       sym->name, name, &loc);
  if (sym->attr.value)
    gfc_error ("VALUE object %qs in %s clause at %L",
	       sym->name, name, &loc);
  check_array_not_assumed (sym, loc, name);
}


struct resolve_omp_udr_callback_data
{
  gfc_symbol *sym1, *sym2;
};


static int
resolve_omp_udr_callback (gfc_expr **e, int *, void *data)
{
  struct resolve_omp_udr_callback_data *rcd
    = (struct resolve_omp_udr_callback_data *) data;
  if ((*e)->expr_type == EXPR_VARIABLE
      && ((*e)->symtree->n.sym == rcd->sym1
	  || (*e)->symtree->n.sym == rcd->sym2))
    {
      gfc_ref *ref = gfc_get_ref ();
      ref->type = REF_ARRAY;
      ref->u.ar.where = (*e)->where;
      ref->u.ar.as = (*e)->symtree->n.sym->as;
      ref->u.ar.type = AR_FULL;
      ref->u.ar.dimen = 0;
      ref->next = (*e)->ref;
      (*e)->ref = ref;
    }
  return 0;
}


static int
resolve_omp_udr_callback2 (gfc_expr **e, int *, void *)
{
  if ((*e)->expr_type == EXPR_FUNCTION
      && (*e)->value.function.isym == NULL)
    {
      gfc_symbol *sym = (*e)->symtree->n.sym;
      if (!sym->attr.intrinsic
	  && sym->attr.if_source == IFSRC_UNKNOWN)
	gfc_error ("Implicitly declared function %s used in "
		   "!$OMP DECLARE REDUCTION at %L", sym->name, &(*e)->where);
    }
  return 0;
}


static gfc_code *
resolve_omp_udr_clause (gfc_omp_namelist *n, gfc_namespace *ns,
			gfc_symbol *sym1, gfc_symbol *sym2)
{
  gfc_code *copy;
  gfc_symbol sym1_copy, sym2_copy;

  if (ns->code->op == EXEC_ASSIGN)
    {
      copy = gfc_get_code (EXEC_ASSIGN);
      copy->expr1 = gfc_copy_expr (ns->code->expr1);
      copy->expr2 = gfc_copy_expr (ns->code->expr2);
    }
  else
    {
      copy = gfc_get_code (EXEC_CALL);
      copy->symtree = ns->code->symtree;
      copy->ext.actual = gfc_copy_actual_arglist (ns->code->ext.actual);
    }
  copy->loc = ns->code->loc;
  sym1_copy = *sym1;
  sym2_copy = *sym2;
  *sym1 = *n->sym;
  *sym2 = *n->sym;
  sym1->name = sym1_copy.name;
  sym2->name = sym2_copy.name;
  ns->proc_name = ns->parent->proc_name;
  if (n->sym->attr.dimension)
    {
      struct resolve_omp_udr_callback_data rcd;
      rcd.sym1 = sym1;
      rcd.sym2 = sym2;
      gfc_code_walker (&copy, gfc_dummy_code_callback,
		       resolve_omp_udr_callback, &rcd);
    }
  gfc_resolve_code (copy, gfc_current_ns);
  if (copy->op == EXEC_CALL && copy->resolved_isym == NULL)
    {
      gfc_symbol *sym = copy->resolved_sym;
      if (sym
	  && !sym->attr.intrinsic
	  && sym->attr.if_source == IFSRC_UNKNOWN)
	gfc_error ("Implicitly declared subroutine %s used in "
		   "!$OMP DECLARE REDUCTION at %L", sym->name,
		   &copy->loc);
    }
  gfc_code_walker (&copy, gfc_dummy_code_callback,
		   resolve_omp_udr_callback2, NULL);
  *sym1 = sym1_copy;
  *sym2 = sym2_copy;
  return copy;
}

/* OpenMP directive resolving routines.  */

static void
resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
		     gfc_namespace *ns, bool openacc = false)
{
  gfc_omp_namelist *n;
  gfc_expr_list *el;
  int list;
  int ifc;
  bool if_without_mod = false;
  gfc_omp_linear_op linear_op = OMP_LINEAR_DEFAULT;
  static const char *clause_names[]
    = { "PRIVATE", "FIRSTPRIVATE", "LASTPRIVATE", "COPYPRIVATE", "SHARED",
	"COPYIN", "UNIFORM", "ALIGNED", "LINEAR", "DEPEND", "MAP",
	"TO", "FROM", "INCLUSIVE", "EXCLUSIVE",
	"REDUCTION", "REDUCTION" /*inscan*/, "REDUCTION" /*task*/,
	"IN_REDUCTION", "TASK_REDUCTION",
	"DEVICE_RESIDENT", "LINK", "USE_DEVICE",
	"CACHE", "IS_DEVICE_PTR", "USE_DEVICE_PTR", "USE_DEVICE_ADDR",
	"NONTEMPORAL" };
  STATIC_ASSERT (ARRAY_SIZE (clause_names) == OMP_LIST_NUM);

  if (omp_clauses == NULL)
    return;

  if (omp_clauses->orderedc && omp_clauses->orderedc < omp_clauses->collapse)
    gfc_error ("ORDERED clause parameter is less than COLLAPSE at %L",
	       &code->loc);

  if (omp_clauses->if_expr)
    {
      gfc_expr *expr = omp_clauses->if_expr;
      if (!gfc_resolve_expr (expr)
	  || expr->ts.type != BT_LOGICAL || expr->rank != 0)
	gfc_error ("IF clause at %L requires a scalar LOGICAL expression",
		   &expr->where);
      if_without_mod = true;
    }
  for (ifc = 0; ifc < OMP_IF_LAST; ifc++)
    if (omp_clauses->if_exprs[ifc])
      {
	gfc_expr *expr = omp_clauses->if_exprs[ifc];
	bool ok = true;
	if (!gfc_resolve_expr (expr)
	    || expr->ts.type != BT_LOGICAL || expr->rank != 0)
	  gfc_error ("IF clause at %L requires a scalar LOGICAL expression",
		     &expr->where);
	else if (if_without_mod)
	  {
	    gfc_error ("IF clause without modifier at %L used together with "
		       "IF clauses with modifiers",
		       &omp_clauses->if_expr->where);
	    if_without_mod = false;
	  }
	else
	  switch (code->op)
	    {
	    case EXEC_OMP_CANCEL:
	      ok = ifc == OMP_IF_CANCEL;
	      break;

	    case EXEC_OMP_PARALLEL:
	    case EXEC_OMP_PARALLEL_DO:
	    case EXEC_OMP_PARALLEL_SECTIONS:
	    case EXEC_OMP_PARALLEL_WORKSHARE:
	    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO:
	    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO:
	      ok = ifc == OMP_IF_PARALLEL;
	      break;

	    case EXEC_OMP_PARALLEL_DO_SIMD:
	    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD:
	    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
	      ok = ifc == OMP_IF_PARALLEL || ifc == OMP_IF_SIMD;
	      break;

	    case EXEC_OMP_SIMD:
	    case EXEC_OMP_DO_SIMD:
	    case EXEC_OMP_DISTRIBUTE_SIMD:
	    case EXEC_OMP_TEAMS_DISTRIBUTE_SIMD:
	      ok = ifc == OMP_IF_SIMD;
	      break;

	    case EXEC_OMP_TASK:
	      ok = ifc == OMP_IF_TASK;
	      break;

	    case EXEC_OMP_TASKLOOP:
	      ok = ifc == OMP_IF_TASKLOOP;
	      break;

	    case EXEC_OMP_TASKLOOP_SIMD:
	      ok = ifc == OMP_IF_TASKLOOP || ifc == OMP_IF_SIMD;
	      break;

	    case EXEC_OMP_TARGET:
	    case EXEC_OMP_TARGET_TEAMS:
	    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE:
	      ok = ifc == OMP_IF_TARGET;
	      break;

	    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
	    case EXEC_OMP_TARGET_SIMD:
	      ok = ifc == OMP_IF_TARGET || ifc == OMP_IF_SIMD;
	      break;

	    case EXEC_OMP_TARGET_DATA:
	      ok = ifc == OMP_IF_TARGET_DATA;
	      break;

	    case EXEC_OMP_TARGET_UPDATE:
	      ok = ifc == OMP_IF_TARGET_UPDATE;
	      break;

	    case EXEC_OMP_TARGET_ENTER_DATA:
	      ok = ifc == OMP_IF_TARGET_ENTER_DATA;
	      break;

	    case EXEC_OMP_TARGET_EXIT_DATA:
	      ok = ifc == OMP_IF_TARGET_EXIT_DATA;
	      break;

	    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
	    case EXEC_OMP_TARGET_PARALLEL:
	    case EXEC_OMP_TARGET_PARALLEL_DO:
	      ok = ifc == OMP_IF_TARGET || ifc == OMP_IF_PARALLEL;
	      break;

	    case EXEC_OMP_TARGET_PARALLEL_DO_SIMD:
	    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
	      ok = (ifc == OMP_IF_TARGET
		    || ifc == OMP_IF_PARALLEL
		    || ifc == OMP_IF_SIMD);
	      break;

	    default:
	      ok = false;
	      break;
	  }
	if (!ok)
	  {
	    static const char *ifs[] = {
	      "CANCEL",
	      "PARALLEL",
	      "SIMD",
	      "TASK",
	      "TASKLOOP",
	      "TARGET",
	      "TARGET DATA",
	      "TARGET UPDATE",
	      "TARGET ENTER DATA",
	      "TARGET EXIT DATA"
	    };
	    gfc_error ("IF clause modifier %s at %L not appropriate for "
		       "the current OpenMP construct", ifs[ifc], &expr->where);
	  }
      }

  if (omp_clauses->final_expr)
    {
      gfc_expr *expr = omp_clauses->final_expr;
      if (!gfc_resolve_expr (expr)
	  || expr->ts.type != BT_LOGICAL || expr->rank != 0)
	gfc_error ("FINAL clause at %L requires a scalar LOGICAL expression",
		   &expr->where);
    }
  if (omp_clauses->num_threads)
    resolve_positive_int_expr (omp_clauses->num_threads, "NUM_THREADS");
  if (omp_clauses->chunk_size)
    {
      gfc_expr *expr = omp_clauses->chunk_size;
      if (!gfc_resolve_expr (expr)
	  || expr->ts.type != BT_INTEGER || expr->rank != 0)
	gfc_error ("SCHEDULE clause's chunk_size at %L requires "
		   "a scalar INTEGER expression", &expr->where);
      else if (expr->expr_type == EXPR_CONSTANT
	       && expr->ts.type == BT_INTEGER
	       && mpz_sgn (expr->value.integer) <= 0)
	gfc_warning (0, "INTEGER expression of SCHEDULE clause's chunk_size "
		     "at %L must be positive", &expr->where);
    }
  if (omp_clauses->sched_kind != OMP_SCHED_NONE
      && omp_clauses->sched_nonmonotonic)
    {
      if (omp_clauses->sched_monotonic)
	gfc_error ("Both MONOTONIC and NONMONOTONIC schedule modifiers "
		   "specified at %L", &code->loc);
      else if (omp_clauses->ordered)
	gfc_error ("NONMONOTONIC schedule modifier specified with ORDERED "
		   "clause at %L", &code->loc);
    }

  /* Check that no symbol appears on multiple clauses, except that
     a symbol can appear on both firstprivate and lastprivate.  */
  for (list = 0; list < OMP_LIST_NUM; list++)
    for (n = omp_clauses->lists[list]; n; n = n->next)
      {
	n->sym->mark = 0;
	n->sym->comp_mark = 0;
	if (n->sym->attr.flavor == FL_VARIABLE
	    || n->sym->attr.proc_pointer
	    || (!code && (!n->sym->attr.dummy || n->sym->ns != ns)))
	  {
	    if (!code && (!n->sym->attr.dummy || n->sym->ns != ns))
	      gfc_error ("Variable %qs is not a dummy argument at %L",
			 n->sym->name, &n->where);
	    continue;
	  }
	if (n->sym->attr.flavor == FL_PROCEDURE
	    && n->sym->result == n->sym
	    && n->sym->attr.function)
	  {
	    if (gfc_current_ns->proc_name == n->sym
		|| (gfc_current_ns->parent
		    && gfc_current_ns->parent->proc_name == n->sym))
	      continue;
	    if (gfc_current_ns->proc_name->attr.entry_master)
	      {
		gfc_entry_list *el = gfc_current_ns->entries;
		for (; el; el = el->next)
		  if (el->sym == n->sym)
		    break;
		if (el)
		  continue;
	      }
	    if (gfc_current_ns->parent
		&& gfc_current_ns->parent->proc_name->attr.entry_master)
	      {
		gfc_entry_list *el = gfc_current_ns->parent->entries;
		for (; el; el = el->next)
		  if (el->sym == n->sym)
		    break;
		if (el)
		  continue;
	      }
	  }
	if (list == OMP_LIST_MAP
	    && n->sym->attr.flavor == FL_PARAMETER)
	  {
	    if (openacc)
	      gfc_error ("Object %qs is not a variable at %L; parameters"
			 " cannot be and need not be copied", n->sym->name,
			 &n->where);
	    else
	      gfc_error ("Object %qs is not a variable at %L; parameters"
			 " cannot be and need not be mapped", n->sym->name,
			 &n->where);
	  }
	else
	  gfc_error ("Object %qs is not a variable at %L", n->sym->name,
		     &n->where);
      }
  if (omp_clauses->lists[OMP_LIST_REDUCTION_INSCAN]
      && code->op != EXEC_OMP_DO
      && code->op != EXEC_OMP_SIMD
      && code->op != EXEC_OMP_DO_SIMD
      && code->op != EXEC_OMP_PARALLEL_DO
      && code->op != EXEC_OMP_PARALLEL_DO_SIMD)
    gfc_error ("%<inscan%> REDUCTION clause on construct other than DO, SIMD, "
	       "DO SIMD, PARALLEL DO, PARALLEL DO SIMD at %L",
	       &omp_clauses->lists[OMP_LIST_REDUCTION_INSCAN]->where);

  for (list = 0; list < OMP_LIST_NUM; list++)
    if (list != OMP_LIST_FIRSTPRIVATE
	&& list != OMP_LIST_LASTPRIVATE
	&& list != OMP_LIST_ALIGNED
	&& list != OMP_LIST_DEPEND
	&& (list != OMP_LIST_MAP || openacc)
	&& list != OMP_LIST_FROM
	&& list != OMP_LIST_TO
	&& (list != OMP_LIST_REDUCTION || !openacc)
	&& list != OMP_LIST_REDUCTION_INSCAN
	&& list != OMP_LIST_REDUCTION_TASK
	&& list != OMP_LIST_IN_REDUCTION
	&& list != OMP_LIST_TASK_REDUCTION)
      for (n = omp_clauses->lists[list]; n; n = n->next)
	{
	  bool component_ref_p = false;

	  /* Allow multiple components of the same (e.g. derived-type)
	     variable here.  Duplicate components are detected elsewhere.  */
	  if (n->expr && n->expr->expr_type == EXPR_VARIABLE)
	    for (gfc_ref *ref = n->expr->ref; ref; ref = ref->next)
	      if (ref->type == REF_COMPONENT)
		component_ref_p = true;
	  if ((!component_ref_p && n->sym->comp_mark)
	      || (component_ref_p && n->sym->mark))
	    gfc_error ("Symbol %qs has mixed component and non-component "
		       "accesses at %L", n->sym->name, &n->where);
	  else if (n->sym->mark)
	    gfc_error ("Symbol %qs present on multiple clauses at %L",
		       n->sym->name, &n->where);
	  else
	    {
	      if (component_ref_p)
		n->sym->comp_mark = 1;
	      else
		n->sym->mark = 1;
	    }
	}

  gcc_assert (OMP_LIST_LASTPRIVATE == OMP_LIST_FIRSTPRIVATE + 1);
  for (list = OMP_LIST_FIRSTPRIVATE; list <= OMP_LIST_LASTPRIVATE; list++)
    for (n = omp_clauses->lists[list]; n; n = n->next)
      if (n->sym->mark)
	{
	  gfc_error ("Symbol %qs present on multiple clauses at %L",
		     n->sym->name, &n->where);
	  n->sym->mark = 0;
	}

  for (n = omp_clauses->lists[OMP_LIST_FIRSTPRIVATE]; n; n = n->next)
    {
      if (n->sym->mark)
	gfc_error ("Symbol %qs present on multiple clauses at %L",
		   n->sym->name, &n->where);
      else
	n->sym->mark = 1;
    }
  for (n = omp_clauses->lists[OMP_LIST_LASTPRIVATE]; n; n = n->next)
    n->sym->mark = 0;

  for (n = omp_clauses->lists[OMP_LIST_LASTPRIVATE]; n; n = n->next)
    {
      if (n->sym->mark)
	gfc_error ("Symbol %qs present on multiple clauses at %L",
		   n->sym->name, &n->where);
      else
	n->sym->mark = 1;
    }

  for (n = omp_clauses->lists[OMP_LIST_ALIGNED]; n; n = n->next)
    n->sym->mark = 0;

  for (n = omp_clauses->lists[OMP_LIST_ALIGNED]; n; n = n->next)
    {
      if (n->sym->mark)
	gfc_error ("Symbol %qs present on multiple clauses at %L",
		   n->sym->name, &n->where);
      else
	n->sym->mark = 1;
    }

  /* OpenACC reductions.  */
  if (openacc)
    {
      for (n = omp_clauses->lists[OMP_LIST_REDUCTION]; n; n = n->next)
	n->sym->mark = 0;

      for (n = omp_clauses->lists[OMP_LIST_REDUCTION]; n; n = n->next)
	{
	  if (n->sym->mark)
	    gfc_error ("Symbol %qs present on multiple clauses at %L",
		       n->sym->name, &n->where);
	  else
	    n->sym->mark = 1;

	  /* OpenACC does not support reductions on arrays.  */
	  if (n->sym->as)
	    gfc_error ("Array %qs is not permitted in reduction at %L",
		       n->sym->name, &n->where);
	}
    }
  
  for (n = omp_clauses->lists[OMP_LIST_TO]; n; n = n->next)
    n->sym->mark = 0;
  for (n = omp_clauses->lists[OMP_LIST_FROM]; n; n = n->next)
    if (n->expr == NULL)
      n->sym->mark = 1;
  for (n = omp_clauses->lists[OMP_LIST_TO]; n; n = n->next)
    {
      if (n->expr == NULL && n->sym->mark)
	gfc_error ("Symbol %qs present on both FROM and TO clauses at %L",
		   n->sym->name, &n->where);
      else
	n->sym->mark = 1;
    }

  bool has_inscan = false, has_notinscan = false;
  for (list = 0; list < OMP_LIST_NUM; list++)
    if ((n = omp_clauses->lists[list]) != NULL)
      {
	const char *name = clause_names[list];

	switch (list)
	  {
	  case OMP_LIST_COPYIN:
	    for (; n != NULL; n = n->next)
	      {
		if (!n->sym->attr.threadprivate)
		  gfc_error ("Non-THREADPRIVATE object %qs in COPYIN clause"
			     " at %L", n->sym->name, &n->where);
	      }
	    break;
	  case OMP_LIST_COPYPRIVATE:
	    for (; n != NULL; n = n->next)
	      {
		if (n->sym->as && n->sym->as->type == AS_ASSUMED_SIZE)
		  gfc_error ("Assumed size array %qs in COPYPRIVATE clause "
			     "at %L", n->sym->name, &n->where);
		if (n->sym->attr.pointer && n->sym->attr.intent == INTENT_IN)
		  gfc_error ("INTENT(IN) POINTER %qs in COPYPRIVATE clause "
			     "at %L", n->sym->name, &n->where);
	      }
	    break;
	  case OMP_LIST_SHARED:
	    for (; n != NULL; n = n->next)
	      {
		if (n->sym->attr.threadprivate)
		  gfc_error ("THREADPRIVATE object %qs in SHARED clause at "
			     "%L", n->sym->name, &n->where);
		if (n->sym->attr.cray_pointee)
		  gfc_error ("Cray pointee %qs in SHARED clause at %L",
			    n->sym->name, &n->where);
		if (n->sym->attr.associate_var)
		  gfc_error ("ASSOCIATE name %qs in SHARED clause at %L",
			     n->sym->name, &n->where);
		if (omp_clauses->detach
		    && n->sym == omp_clauses->detach->symtree->n.sym)
		  gfc_error ("DETACH event handle %qs in SHARED clause at %L",
			     n->sym->name, &n->where);
	      }
	    break;
	  case OMP_LIST_ALIGNED:
	    for (; n != NULL; n = n->next)
	      {
		if (!n->sym->attr.pointer
		    && !n->sym->attr.allocatable
		    && !n->sym->attr.cray_pointer
		    && (n->sym->ts.type != BT_DERIVED
			|| (n->sym->ts.u.derived->from_intmod
			    != INTMOD_ISO_C_BINDING)
			|| (n->sym->ts.u.derived->intmod_sym_id
			    != ISOCBINDING_PTR)))
		  gfc_error ("%qs in ALIGNED clause must be POINTER, "
			     "ALLOCATABLE, Cray pointer or C_PTR at %L",
			     n->sym->name, &n->where);
		else if (n->expr)
		  {
		    gfc_expr *expr = n->expr;
		    int alignment = 0;
		    if (!gfc_resolve_expr (expr)
			|| expr->ts.type != BT_INTEGER
			|| expr->rank != 0
			|| gfc_extract_int (expr, &alignment)
			|| alignment <= 0)
		      gfc_error ("%qs in ALIGNED clause at %L requires a scalar "
				 "positive constant integer alignment "
				 "expression", n->sym->name, &n->where);
		  }
	      }
	    break;
	  case OMP_LIST_DEPEND:
	  case OMP_LIST_MAP:
	  case OMP_LIST_TO:
	  case OMP_LIST_FROM:
	  case OMP_LIST_CACHE:
	    for (; n != NULL; n = n->next)
	      {
		if (list == OMP_LIST_DEPEND)
		  {
		    if (n->u.depend_op == OMP_DEPEND_SINK_FIRST
			|| n->u.depend_op == OMP_DEPEND_SINK)
		      {
			if (code->op != EXEC_OMP_ORDERED)
			  gfc_error ("SINK dependence type only allowed "
				     "on ORDERED directive at %L", &n->where);
			else if (omp_clauses->depend_source)
			  {
			    gfc_error ("DEPEND SINK used together with "
				       "DEPEND SOURCE on the same construct "
				       "at %L", &n->where);
			    omp_clauses->depend_source = false;
			  }
			else if (n->expr)
			  {
			    if (!gfc_resolve_expr (n->expr)
				|| n->expr->ts.type != BT_INTEGER
				|| n->expr->rank != 0)
			      gfc_error ("SINK addend not a constant integer "
					 "at %L", &n->where);
			  }
			continue;
		      }
		    else if (code->op == EXEC_OMP_ORDERED)
		      gfc_error ("Only SOURCE or SINK dependence types "
				 "are allowed on ORDERED directive at %L",
				 &n->where);
		  }
		gfc_ref *lastref = NULL, *lastslice = NULL;
		bool resolved = false;
		if (n->expr)
		  {
		    lastref = n->expr->ref;
		    resolved = gfc_resolve_expr (n->expr);

		    /* Look through component refs to find last array
		       reference.  */
		    if (resolved)
		      {
			for (gfc_ref *ref = n->expr->ref; ref; ref = ref->next)
			  if (ref->type == REF_COMPONENT
			      || ref->type == REF_SUBSTRING
			      || ref->type == REF_INQUIRY)
			    lastref = ref;
			  else if (ref->type == REF_ARRAY)
			    {
			      for (int i = 0; i < ref->u.ar.dimen; i++)
				if (ref->u.ar.dimen_type[i] == DIMEN_RANGE)
				  lastslice = ref;

			      lastref = ref;
			    }

			/* The "!$acc cache" directive allows rectangular
			   subarrays to be specified, with some restrictions
			   on the form of bounds (not implemented).
			   Only raise an error here if we're really sure the
			   array isn't contiguous.  An expression such as
			   arr(-n:n,-n:n) could be contiguous even if it looks
			   like it may not be.  */
			if (code->op != EXEC_OACC_UPDATE
			    && list != OMP_LIST_CACHE
			    && list != OMP_LIST_DEPEND
			    && !gfc_is_simply_contiguous (n->expr, false, true)
			    && gfc_is_not_contiguous (n->expr)
			    && !(lastslice
				 && (lastslice->next
				     || lastslice->type != REF_ARRAY)))
			  gfc_error ("Array is not contiguous at %L",
				     &n->where);
		      }
		  }
		if (lastref
		    || (n->expr
			&& (!resolved || n->expr->expr_type != EXPR_VARIABLE)))
		  {
		    if (!lastslice
			&& lastref
			&& lastref->type == REF_SUBSTRING)
		      gfc_error ("Unexpected substring reference in %s clause "
				 "at %L", name, &n->where);
		    else if (!lastslice
			     && lastref
			     && lastref->type == REF_INQUIRY)
		      {
			gcc_assert (lastref->u.i == INQUIRY_RE
				    || lastref->u.i == INQUIRY_IM);
			gfc_error ("Unexpected complex-parts designator "
				   "reference in %s clause at %L",
				   name, &n->where);
		      }
		    else if (!resolved
			     || n->expr->expr_type != EXPR_VARIABLE
			     || (lastslice
				 && (lastslice->next
				     || lastslice->type != REF_ARRAY)))
		      gfc_error ("%qs in %s clause at %L is not a proper "
				 "array section", n->sym->name, name,
				 &n->where);
		    else if (lastslice)
		      {
			int i;
			gfc_array_ref *ar = &lastslice->u.ar;
			for (i = 0; i < ar->dimen; i++)
			  if (ar->stride[i] && code->op != EXEC_OACC_UPDATE)
			    {
			      gfc_error ("Stride should not be specified for "
					 "array section in %s clause at %L",
					 name, &n->where);
			      break;
			    }
			  else if (ar->dimen_type[i] != DIMEN_ELEMENT
				   && ar->dimen_type[i] != DIMEN_RANGE)
			    {
			      gfc_error ("%qs in %s clause at %L is not a "
					 "proper array section",
					 n->sym->name, name, &n->where);
			      break;
			    }
			  else if (list == OMP_LIST_DEPEND
				   && ar->start[i]
				   && ar->start[i]->expr_type == EXPR_CONSTANT
				   && ar->end[i]
				   && ar->end[i]->expr_type == EXPR_CONSTANT
				   && mpz_cmp (ar->start[i]->value.integer,
					       ar->end[i]->value.integer) > 0)
			    {
			      gfc_error ("%qs in DEPEND clause at %L is a "
					 "zero size array section",
					 n->sym->name, &n->where);
			      break;
			    }
		      }
		  }
		else if (openacc)
		  {
		    if (list == OMP_LIST_MAP
			&& n->u.map_op == OMP_MAP_FORCE_DEVICEPTR)
		      resolve_oacc_deviceptr_clause (n->sym, n->where, name);
		    else
		      resolve_oacc_data_clauses (n->sym, n->where, name);
		  }
		else if (list != OMP_LIST_DEPEND
			 && n->sym->as
			 && n->sym->as->type == AS_ASSUMED_SIZE)
		  gfc_error ("Assumed size array %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (!openacc
		    && list == OMP_LIST_MAP
		    && n->sym->ts.type == BT_DERIVED
		    && n->sym->ts.u.derived->attr.alloc_comp)
		  gfc_error ("List item %qs with allocatable components is not "
			     "permitted in map clause at %L", n->sym->name,
			     &n->where);
		if (list == OMP_LIST_MAP && !openacc)
		  switch (code->op)
		    {
		    case EXEC_OMP_TARGET:
		    case EXEC_OMP_TARGET_DATA:
		      switch (n->u.map_op)
			{
			case OMP_MAP_TO:
			case OMP_MAP_ALWAYS_TO:
			case OMP_MAP_FROM:
			case OMP_MAP_ALWAYS_FROM:
			case OMP_MAP_TOFROM:
			case OMP_MAP_ALWAYS_TOFROM:
			case OMP_MAP_ALLOC:
			  break;
			default:
			  gfc_error ("TARGET%s with map-type other than TO, "
				     "FROM, TOFROM, or ALLOC on MAP clause "
				     "at %L",
				     code->op == EXEC_OMP_TARGET
				     ? "" : " DATA", &n->where);
			  break;
			}
		      break;
		    case EXEC_OMP_TARGET_ENTER_DATA:
		      switch (n->u.map_op)
			{
			case OMP_MAP_TO:
			case OMP_MAP_ALWAYS_TO:
			case OMP_MAP_ALLOC:
			  break;
			default:
			  gfc_error ("TARGET ENTER DATA with map-type other "
				     "than TO, or ALLOC on MAP clause at %L",
				     &n->where);
			  break;
			}
		      break;
		    case EXEC_OMP_TARGET_EXIT_DATA:
		      switch (n->u.map_op)
			{
			case OMP_MAP_FROM:
			case OMP_MAP_ALWAYS_FROM:
			case OMP_MAP_RELEASE:
			case OMP_MAP_DELETE:
			  break;
			default:
			  gfc_error ("TARGET EXIT DATA with map-type other "
				     "than FROM, RELEASE, or DELETE on MAP "
				     "clause at %L", &n->where);
			  break;
			}
		      break;
		    default:
		      break;
		    }
	      }

	    if (list != OMP_LIST_DEPEND)
	      for (n = omp_clauses->lists[list]; n != NULL; n = n->next)
		{
		  n->sym->attr.referenced = 1;
		  if (n->sym->attr.threadprivate)
		    gfc_error ("THREADPRIVATE object %qs in %s clause at %L",
			       n->sym->name, name, &n->where);
		  if (n->sym->attr.cray_pointee)
		    gfc_error ("Cray pointee %qs in %s clause at %L",
			       n->sym->name, name, &n->where);
		}
	    break;
	  case OMP_LIST_IS_DEVICE_PTR:
	    for (n = omp_clauses->lists[list]; n != NULL; n = n->next)
	      {
		if (!n->sym->attr.dummy)
		  gfc_error ("Non-dummy object %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.allocatable
		    || (n->sym->ts.type == BT_CLASS
			&& CLASS_DATA (n->sym)->attr.allocatable))
		  gfc_error ("ALLOCATABLE object %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.pointer
		    || (n->sym->ts.type == BT_CLASS
			&& CLASS_DATA (n->sym)->attr.pointer))
		  gfc_error ("POINTER object %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.value)
		  gfc_error ("VALUE object %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
	      }
	    break;
	  case OMP_LIST_USE_DEVICE_PTR:
	  case OMP_LIST_USE_DEVICE_ADDR:
	    /* FIXME: Handle OMP_LIST_USE_DEVICE_PTR.  */
	    break;
	  default:
	    for (; n != NULL; n = n->next)
	      {
		bool bad = false;
		bool is_reduction = (list == OMP_LIST_REDUCTION
				     || list == OMP_LIST_REDUCTION_INSCAN
				     || list == OMP_LIST_REDUCTION_TASK
				     || list == OMP_LIST_IN_REDUCTION
				     || list == OMP_LIST_TASK_REDUCTION);
		if (list == OMP_LIST_REDUCTION_INSCAN)
		  has_inscan = true;
		else if (is_reduction)
		  has_notinscan = true;
		if (has_inscan && has_notinscan && is_reduction)
		  {
		    gfc_error ("%<inscan%> and non-%<inscan%> %<reduction%> "
			       "clauses on the same construct at %L",
			       &n->where);
		    break;
		  }
		if (n->sym->attr.threadprivate)
		  gfc_error ("THREADPRIVATE object %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.cray_pointee)
		  gfc_error ("Cray pointee %qs in %s clause at %L",
			    n->sym->name, name, &n->where);
		if (n->sym->attr.associate_var)
		  gfc_error ("ASSOCIATE name %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (list != OMP_LIST_PRIVATE && is_reduction)
		  {
		    if (n->sym->attr.proc_pointer)
		      gfc_error ("Procedure pointer %qs in %s clause at %L",
				 n->sym->name, name, &n->where);
		    if (n->sym->attr.pointer)
		      gfc_error ("POINTER object %qs in %s clause at %L",
				 n->sym->name, name, &n->where);
		    if (n->sym->attr.cray_pointer)
		      gfc_error ("Cray pointer %qs in %s clause at %L",
				 n->sym->name, name, &n->where);
		  }
		if (code
		    && (oacc_is_loop (code)
			|| code->op == EXEC_OACC_PARALLEL
			|| code->op == EXEC_OACC_SERIAL))
		  check_array_not_assumed (n->sym, n->where, name);
		else if (n->sym->as && n->sym->as->type == AS_ASSUMED_SIZE)
		  gfc_error ("Assumed size array %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.in_namelist && !is_reduction)
		  gfc_error ("Variable %qs in %s clause is used in "
			     "NAMELIST statement at %L",
			     n->sym->name, name, &n->where);
		if (n->sym->attr.pointer && n->sym->attr.intent == INTENT_IN)
		  switch (list)
		    {
		    case OMP_LIST_PRIVATE:
		    case OMP_LIST_LASTPRIVATE:
		    case OMP_LIST_LINEAR:
		    /* case OMP_LIST_REDUCTION: */
		      gfc_error ("INTENT(IN) POINTER %qs in %s clause at %L",
				 n->sym->name, name, &n->where);
		      break;
		    default:
		      break;
		    }
		if (omp_clauses->detach
		    && (list == OMP_LIST_PRIVATE
			|| list == OMP_LIST_FIRSTPRIVATE
			|| list == OMP_LIST_LASTPRIVATE)
		    && n->sym == omp_clauses->detach->symtree->n.sym)
		  gfc_error ("DETACH event handle %qs in %s clause at %L",
			     n->sym->name, name, &n->where);
		switch (list)
		  {
		  case OMP_LIST_REDUCTION_INSCAN:
		  case OMP_LIST_REDUCTION_TASK:
		    if (code && (code->op == EXEC_OMP_TASKLOOP
				 || code->op == EXEC_OMP_TEAMS
				 || code->op == EXEC_OMP_TEAMS_DISTRIBUTE))
		      {
			gfc_error ("Only DEFAULT permitted as reduction-"
				   "modifier in REDUCTION clause at %L",
				   &n->where);
			break;
		      }
		    gcc_fallthrough ();
		  case OMP_LIST_REDUCTION:
		  case OMP_LIST_IN_REDUCTION:
		  case OMP_LIST_TASK_REDUCTION:
		    switch (n->u.reduction_op)
		      {
		      case OMP_REDUCTION_PLUS:
		      case OMP_REDUCTION_TIMES:
		      case OMP_REDUCTION_MINUS:
			if (!gfc_numeric_ts (&n->sym->ts))
			  bad = true;
			break;
		      case OMP_REDUCTION_AND:
		      case OMP_REDUCTION_OR:
		      case OMP_REDUCTION_EQV:
		      case OMP_REDUCTION_NEQV:
			if (n->sym->ts.type != BT_LOGICAL)
			  bad = true;
			break;
		      case OMP_REDUCTION_MAX:
		      case OMP_REDUCTION_MIN:
			if (n->sym->ts.type != BT_INTEGER
			    && n->sym->ts.type != BT_REAL)
			  bad = true;
			break;
		      case OMP_REDUCTION_IAND:
		      case OMP_REDUCTION_IOR:
		      case OMP_REDUCTION_IEOR:
			if (n->sym->ts.type != BT_INTEGER)
			  bad = true;
			break;
		      case OMP_REDUCTION_USER:
			bad = true;
			break;
		      default:
			break;
		      }
		    if (!bad)
		      n->udr = NULL;
		    else
		      {
			const char *udr_name = NULL;
			if (n->udr)
			  {
			    udr_name = n->udr->udr->name;
			    n->udr->udr
			      = gfc_find_omp_udr (NULL, udr_name,
						  &n->sym->ts);
			    if (n->udr->udr == NULL)
			      {
				free (n->udr);
				n->udr = NULL;
			      }
			  }
			if (n->udr == NULL)
			  {
			    if (udr_name == NULL)
			      switch (n->u.reduction_op)
				{
				case OMP_REDUCTION_PLUS:
				case OMP_REDUCTION_TIMES:
				case OMP_REDUCTION_MINUS:
				case OMP_REDUCTION_AND:
				case OMP_REDUCTION_OR:
				case OMP_REDUCTION_EQV:
				case OMP_REDUCTION_NEQV:
				  udr_name = gfc_op2string ((gfc_intrinsic_op)
							    n->u.reduction_op);
				  break;
				case OMP_REDUCTION_MAX:
				  udr_name = "max";
				  break;
				case OMP_REDUCTION_MIN:
				  udr_name = "min";
				  break;
				case OMP_REDUCTION_IAND:
				  udr_name = "iand";
				  break;
				case OMP_REDUCTION_IOR:
				  udr_name = "ior";
				  break;
				case OMP_REDUCTION_IEOR:
				  udr_name = "ieor";
				  break;
				default:
				  gcc_unreachable ();
				}
			    gfc_error ("!$OMP DECLARE REDUCTION %s not found "
				       "for type %s at %L", udr_name,
				       gfc_typename (&n->sym->ts), &n->where);
			  }
			else
			  {
			    gfc_omp_udr *udr = n->udr->udr;
			    n->u.reduction_op = OMP_REDUCTION_USER;
			    n->udr->combiner
			      = resolve_omp_udr_clause (n, udr->combiner_ns,
							udr->omp_out,
							udr->omp_in);
			    if (udr->initializer_ns)
			      n->udr->initializer
				= resolve_omp_udr_clause (n,
							  udr->initializer_ns,
							  udr->omp_priv,
							  udr->omp_orig);
			  }
		      }
		    break;
		  case OMP_LIST_LINEAR:
		    if (code
			&& n->u.linear_op != OMP_LINEAR_DEFAULT
			&& n->u.linear_op != linear_op)
		      {
			gfc_error ("LINEAR clause modifier used on DO or SIMD"
				   " construct at %L", &n->where);
			linear_op = n->u.linear_op;
		      }
		    else if (omp_clauses->orderedc)
		      gfc_error ("LINEAR clause specified together with "
				 "ORDERED clause with argument at %L",
				 &n->where);
		    else if (n->u.linear_op != OMP_LINEAR_REF
			     && n->sym->ts.type != BT_INTEGER)
		      gfc_error ("LINEAR variable %qs must be INTEGER "
				 "at %L", n->sym->name, &n->where);
		    else if ((n->u.linear_op == OMP_LINEAR_REF
			      || n->u.linear_op == OMP_LINEAR_UVAL)
			     && n->sym->attr.value)
		      gfc_error ("LINEAR dummy argument %qs with VALUE "
				 "attribute with %s modifier at %L",
				 n->sym->name,
				 n->u.linear_op == OMP_LINEAR_REF
				 ? "REF" : "UVAL", &n->where);
		    else if (n->expr)
		      {
			gfc_expr *expr = n->expr;
			if (!gfc_resolve_expr (expr)
			    || expr->ts.type != BT_INTEGER
			    || expr->rank != 0)
			  gfc_error ("%qs in LINEAR clause at %L requires "
				     "a scalar integer linear-step expression",
				     n->sym->name, &n->where);
			else if (!code && expr->expr_type != EXPR_CONSTANT)
			  {
			    if (expr->expr_type == EXPR_VARIABLE
				&& expr->symtree->n.sym->attr.dummy
				&& expr->symtree->n.sym->ns == ns)
			      {
				gfc_omp_namelist *n2;
				for (n2 = omp_clauses->lists[OMP_LIST_UNIFORM];
				     n2; n2 = n2->next)
				  if (n2->sym == expr->symtree->n.sym)
				    break;
				if (n2)
				  break;
			      }
			    gfc_error ("%qs in LINEAR clause at %L requires "
				       "a constant integer linear-step "
				       "expression or dummy argument "
				       "specified in UNIFORM clause",
				       n->sym->name, &n->where);
			  }
		      }
		    break;
		  /* Workaround for PR middle-end/26316, nothing really needs
		     to be done here for OMP_LIST_PRIVATE.  */
		  case OMP_LIST_PRIVATE:
		    gcc_assert (code && code->op != EXEC_NOP);
		    break;
		  case OMP_LIST_USE_DEVICE:
		      if (n->sym->attr.allocatable
			  || (n->sym->ts.type == BT_CLASS && CLASS_DATA (n->sym)
			      && CLASS_DATA (n->sym)->attr.allocatable))
			gfc_error ("ALLOCATABLE object %qs in %s clause at %L",
				   n->sym->name, name, &n->where);
		      if (n->sym->ts.type == BT_CLASS
			  && CLASS_DATA (n->sym)
			  && CLASS_DATA (n->sym)->attr.class_pointer)
			gfc_error ("POINTER object %qs of polymorphic type in "
				   "%s clause at %L", n->sym->name, name,
				   &n->where);
		      if (n->sym->attr.cray_pointer)
			gfc_error ("Cray pointer object %qs in %s clause at %L",
				   n->sym->name, name, &n->where);
		      else if (n->sym->attr.cray_pointee)
			gfc_error ("Cray pointee object %qs in %s clause at %L",
				   n->sym->name, name, &n->where);
		      else if (n->sym->attr.flavor == FL_VARIABLE
			       && !n->sym->as
			       && !n->sym->attr.pointer)
			gfc_error ("%s clause variable %qs at %L is neither "
				   "a POINTER nor an array", name,
				   n->sym->name, &n->where);
		      /* FALLTHRU */
		  case OMP_LIST_DEVICE_RESIDENT:
		    check_symbol_not_pointer (n->sym, n->where, name);
		    check_array_not_assumed (n->sym, n->where, name);
		    break;
		  default:
		    break;
		  }
	      }
	    break;
	  }
      }
  /* OpenMP 5.1: use_device_ptr acts like use_device_addr, except for
     type(c_ptr).  */
  if (omp_clauses->lists[OMP_LIST_USE_DEVICE_PTR])
    {
      gfc_omp_namelist *n_prev, *n_next, *n_addr;
      n_addr = omp_clauses->lists[OMP_LIST_USE_DEVICE_ADDR];
      for (; n_addr && n_addr->next; n_addr = n_addr->next)
	;
      n_prev = NULL;
      n = omp_clauses->lists[OMP_LIST_USE_DEVICE_PTR];
      while (n)
	{
	  n_next = n->next;
	  if (n->sym->ts.type != BT_DERIVED
	      || n->sym->ts.u.derived->ts.f90_type != BT_VOID)
	    {
	      n->next = NULL;
	      if (n_addr)
		n_addr->next = n;
	      else
		omp_clauses->lists[OMP_LIST_USE_DEVICE_ADDR] = n;
	      n_addr = n;
	      if (n_prev)
		n_prev->next = n_next;
	      else
		omp_clauses->lists[OMP_LIST_USE_DEVICE_PTR] = n_next;
	    }
	  else
	    n_prev = n;
	  n = n_next;
	}
    }
  if (omp_clauses->safelen_expr)
    resolve_positive_int_expr (omp_clauses->safelen_expr, "SAFELEN");
  if (omp_clauses->simdlen_expr)
    resolve_positive_int_expr (omp_clauses->simdlen_expr, "SIMDLEN");
  if (omp_clauses->num_teams)
    resolve_positive_int_expr (omp_clauses->num_teams, "NUM_TEAMS");
  if (omp_clauses->device)
    resolve_nonnegative_int_expr (omp_clauses->device, "DEVICE");
  if (omp_clauses->hint)
    {
      resolve_scalar_int_expr (omp_clauses->hint, "HINT");
    if (omp_clauses->hint->ts.type != BT_INTEGER
	|| omp_clauses->hint->expr_type != EXPR_CONSTANT
	|| mpz_sgn (omp_clauses->hint->value.integer) < 0)
      gfc_error ("Value of HINT clause at %L shall be a valid "
		 "constant hint expression", &omp_clauses->hint->where);
    }
  if (omp_clauses->priority)
    resolve_nonnegative_int_expr (omp_clauses->priority, "PRIORITY");
  if (omp_clauses->dist_chunk_size)
    {
      gfc_expr *expr = omp_clauses->dist_chunk_size;
      if (!gfc_resolve_expr (expr)
	  || expr->ts.type != BT_INTEGER || expr->rank != 0)
	gfc_error ("DIST_SCHEDULE clause's chunk_size at %L requires "
		   "a scalar INTEGER expression", &expr->where);
    }
  if (omp_clauses->thread_limit)
    resolve_positive_int_expr (omp_clauses->thread_limit, "THREAD_LIMIT");
  if (omp_clauses->grainsize)
    resolve_positive_int_expr (omp_clauses->grainsize, "GRAINSIZE");
  if (omp_clauses->num_tasks)
    resolve_positive_int_expr (omp_clauses->num_tasks, "NUM_TASKS");
  if (omp_clauses->async)
    if (omp_clauses->async_expr)
      resolve_scalar_int_expr (omp_clauses->async_expr, "ASYNC");
  if (omp_clauses->num_gangs_expr)
    resolve_positive_int_expr (omp_clauses->num_gangs_expr, "NUM_GANGS");
  if (omp_clauses->num_workers_expr)
    resolve_positive_int_expr (omp_clauses->num_workers_expr, "NUM_WORKERS");
  if (omp_clauses->vector_length_expr)
    resolve_positive_int_expr (omp_clauses->vector_length_expr,
			       "VECTOR_LENGTH");
  if (omp_clauses->gang_num_expr)
    resolve_positive_int_expr (omp_clauses->gang_num_expr, "GANG");
  if (omp_clauses->gang_static_expr)
    resolve_positive_int_expr (omp_clauses->gang_static_expr, "GANG");
  if (omp_clauses->worker_expr)
    resolve_positive_int_expr (omp_clauses->worker_expr, "WORKER");
  if (omp_clauses->vector_expr)
    resolve_positive_int_expr (omp_clauses->vector_expr, "VECTOR");
  for (el = omp_clauses->wait_list; el; el = el->next)
    resolve_scalar_int_expr (el->expr, "WAIT");
  if (omp_clauses->collapse && omp_clauses->tile_list)
    gfc_error ("Incompatible use of TILE and COLLAPSE at %L", &code->loc);
  if (omp_clauses->depend_source && code->op != EXEC_OMP_ORDERED)
    gfc_error ("SOURCE dependence type only allowed "
	       "on ORDERED directive at %L", &code->loc);
  if (!openacc
      && code
      && omp_clauses->lists[OMP_LIST_MAP] == NULL
      && omp_clauses->lists[OMP_LIST_USE_DEVICE_PTR] == NULL
      && omp_clauses->lists[OMP_LIST_USE_DEVICE_ADDR] == NULL)
    {
      const char *p = NULL;
      switch (code->op)
	{
	case EXEC_OMP_TARGET_ENTER_DATA: p = "TARGET ENTER DATA"; break;
	case EXEC_OMP_TARGET_EXIT_DATA: p = "TARGET EXIT DATA"; break;
	default: break;
	}
      if (code->op == EXEC_OMP_TARGET_DATA)
	gfc_error ("TARGET DATA must contain at least one MAP, USE_DEVICE_PTR, "
		   "or USE_DEVICE_ADDR clause at %L", &code->loc);
      else if (p)
	gfc_error ("%s must contain at least one MAP clause at %L",
		   p, &code->loc);
    }
  if (!openacc && omp_clauses->mergeable && omp_clauses->detach)
    gfc_error ("%<DETACH%> clause at %L must not be used together with "
	       "%<MERGEABLE%> clause", &omp_clauses->detach->where);
}


/* Return true if SYM is ever referenced in EXPR except in the SE node.  */

static bool
expr_references_sym (gfc_expr *e, gfc_symbol *s, gfc_expr *se)
{
  gfc_actual_arglist *arg;
  if (e == NULL || e == se)
    return false;
  switch (e->expr_type)
    {
    case EXPR_CONSTANT:
    case EXPR_NULL:
    case EXPR_VARIABLE:
    case EXPR_STRUCTURE:
    case EXPR_ARRAY:
      if (e->symtree != NULL
	  && e->symtree->n.sym == s)
	return true;
      return false;
    case EXPR_SUBSTRING:
      if (e->ref != NULL
	  && (expr_references_sym (e->ref->u.ss.start, s, se)
	      || expr_references_sym (e->ref->u.ss.end, s, se)))
	return true;
      return false;
    case EXPR_OP:
      if (expr_references_sym (e->value.op.op2, s, se))
	return true;
      return expr_references_sym (e->value.op.op1, s, se);
    case EXPR_FUNCTION:
      for (arg = e->value.function.actual; arg; arg = arg->next)
	if (expr_references_sym (arg->expr, s, se))
	  return true;
      return false;
    default:
      gcc_unreachable ();
    }
}


/* If EXPR is a conversion function that widens the type
   if WIDENING is true or narrows the type if WIDENING is false,
   return the inner expression, otherwise return NULL.  */

static gfc_expr *
is_conversion (gfc_expr *expr, bool widening)
{
  gfc_typespec *ts1, *ts2;

  if (expr->expr_type != EXPR_FUNCTION
      || expr->value.function.isym == NULL
      || expr->value.function.esym != NULL
      || expr->value.function.isym->id != GFC_ISYM_CONVERSION)
    return NULL;

  if (widening)
    {
      ts1 = &expr->ts;
      ts2 = &expr->value.function.actual->expr->ts;
    }
  else
    {
      ts1 = &expr->value.function.actual->expr->ts;
      ts2 = &expr->ts;
    }

  if (ts1->type > ts2->type
      || (ts1->type == ts2->type && ts1->kind > ts2->kind))
    return expr->value.function.actual->expr;

  return NULL;
}


static void
resolve_omp_atomic (gfc_code *code)
{
  gfc_code *atomic_code = code->block;
  gfc_symbol *var;
  gfc_expr *expr2, *expr2_tmp;
  gfc_omp_atomic_op aop
    = (gfc_omp_atomic_op) (atomic_code->ext.omp_clauses->atomic_op
			   & GFC_OMP_ATOMIC_MASK);

  code = code->block->next;
  /* resolve_blocks asserts this is initially EXEC_ASSIGN.
     If it changed to EXEC_NOP, assume an error has been emitted already.  */
  if (code->op == EXEC_NOP)
    return;
  if (code->op != EXEC_ASSIGN)
    {
    unexpected:
      gfc_error ("unexpected !$OMP ATOMIC expression at %L", &code->loc);
      return;
    }
  if (!atomic_code->ext.omp_clauses->capture)
    {
      if (code->next != NULL)
	goto unexpected;
    }
  else
    {
      if (code->next == NULL)
	goto unexpected;
      if (code->next->op == EXEC_NOP)
	return;
      if (code->next->op != EXEC_ASSIGN || code->next->next)
	{
	  code = code->next;
	  goto unexpected;
	}
    }

  if (code->expr1->expr_type != EXPR_VARIABLE
      || code->expr1->symtree == NULL
      || code->expr1->rank != 0
      || (code->expr1->ts.type != BT_INTEGER
	  && code->expr1->ts.type != BT_REAL
	  && code->expr1->ts.type != BT_COMPLEX
	  && code->expr1->ts.type != BT_LOGICAL))
    {
      gfc_error ("!$OMP ATOMIC statement must set a scalar variable of "
		 "intrinsic type at %L", &code->loc);
      return;
    }

  var = code->expr1->symtree->n.sym;
  expr2 = is_conversion (code->expr2, false);
  if (expr2 == NULL)
    {
      if (aop == GFC_OMP_ATOMIC_READ || aop == GFC_OMP_ATOMIC_WRITE)
	expr2 = is_conversion (code->expr2, true);
      if (expr2 == NULL)
	expr2 = code->expr2;
    }

  switch (aop)
    {
    case GFC_OMP_ATOMIC_READ:
      if (expr2->expr_type != EXPR_VARIABLE
	  || expr2->symtree == NULL
	  || expr2->rank != 0
	  || (expr2->ts.type != BT_INTEGER
	      && expr2->ts.type != BT_REAL
	      && expr2->ts.type != BT_COMPLEX
	      && expr2->ts.type != BT_LOGICAL))
	gfc_error ("!$OMP ATOMIC READ statement must read from a scalar "
		   "variable of intrinsic type at %L", &expr2->where);
      return;
    case GFC_OMP_ATOMIC_WRITE:
      if (expr2->rank != 0 || expr_references_sym (code->expr2, var, NULL))
	gfc_error ("expr in !$OMP ATOMIC WRITE assignment var = expr "
		   "must be scalar and cannot reference var at %L",
		   &expr2->where);
      return;
    default:
      break;
    }
  if (atomic_code->ext.omp_clauses->capture)
    {
      expr2_tmp = expr2;
      if (expr2 == code->expr2)
	{
	  expr2_tmp = is_conversion (code->expr2, true);
	  if (expr2_tmp == NULL)
	    expr2_tmp = expr2;
	}
      if (expr2_tmp->expr_type == EXPR_VARIABLE)
	{
	  if (expr2_tmp->symtree == NULL
	      || expr2_tmp->rank != 0
	      || (expr2_tmp->ts.type != BT_INTEGER
		  && expr2_tmp->ts.type != BT_REAL
		  && expr2_tmp->ts.type != BT_COMPLEX
		  && expr2_tmp->ts.type != BT_LOGICAL)
	      || expr2_tmp->symtree->n.sym == var)
	    {
	      gfc_error ("!$OMP ATOMIC CAPTURE capture statement must read from "
			 "a scalar variable of intrinsic type at %L",
			 &expr2_tmp->where);
	      return;
	    }
	  var = expr2_tmp->symtree->n.sym;
	  code = code->next;
	  if (code->expr1->expr_type != EXPR_VARIABLE
	      || code->expr1->symtree == NULL
	      || code->expr1->rank != 0
	      || (code->expr1->ts.type != BT_INTEGER
		  && code->expr1->ts.type != BT_REAL
		  && code->expr1->ts.type != BT_COMPLEX
		  && code->expr1->ts.type != BT_LOGICAL))
	    {
	      gfc_error ("!$OMP ATOMIC CAPTURE update statement must set "
			 "a scalar variable of intrinsic type at %L",
			 &code->expr1->where);
	      return;
	    }
	  if (code->expr1->symtree->n.sym != var)
	    {
	      gfc_error ("!$OMP ATOMIC CAPTURE capture statement reads from "
			 "different variable than update statement writes "
			 "into at %L", &code->expr1->where);
	      return;
	    }
	  expr2 = is_conversion (code->expr2, false);
	  if (expr2 == NULL)
	    expr2 = code->expr2;
	}
    }

  if (gfc_expr_attr (code->expr1).allocatable)
    {
      gfc_error ("!$OMP ATOMIC with ALLOCATABLE variable at %L",
		 &code->loc);
      return;
    }

  if (atomic_code->ext.omp_clauses->capture
      && code->next == NULL
      && code->expr2->rank == 0
      && !expr_references_sym (code->expr2, var, NULL))
    atomic_code->ext.omp_clauses->atomic_op
      = (gfc_omp_atomic_op) (atomic_code->ext.omp_clauses->atomic_op
			     | GFC_OMP_ATOMIC_SWAP);
  else if (expr2->expr_type == EXPR_OP)
    {
      gfc_expr *v = NULL, *e, *c;
      gfc_intrinsic_op op = expr2->value.op.op;
      gfc_intrinsic_op alt_op = INTRINSIC_NONE;

      switch (op)
	{
	case INTRINSIC_PLUS:
	  alt_op = INTRINSIC_MINUS;
	  break;
	case INTRINSIC_TIMES:
	  alt_op = INTRINSIC_DIVIDE;
	  break;
	case INTRINSIC_MINUS:
	  alt_op = INTRINSIC_PLUS;
	  break;
	case INTRINSIC_DIVIDE:
	  alt_op = INTRINSIC_TIMES;
	  break;
	case INTRINSIC_AND:
	case INTRINSIC_OR:
	  break;
	case INTRINSIC_EQV:
	  alt_op = INTRINSIC_NEQV;
	  break;
	case INTRINSIC_NEQV:
	  alt_op = INTRINSIC_EQV;
	  break;
	default:
	  gfc_error ("!$OMP ATOMIC assignment operator must be binary "
		     "+, *, -, /, .AND., .OR., .EQV. or .NEQV. at %L",
		     &expr2->where);
	  return;
	}

      /* Check for var = var op expr resp. var = expr op var where
	 expr doesn't reference var and var op expr is mathematically
	 equivalent to var op (expr) resp. expr op var equivalent to
	 (expr) op var.  We rely here on the fact that the matcher
	 for x op1 y op2 z where op1 and op2 have equal precedence
	 returns (x op1 y) op2 z.  */
      e = expr2->value.op.op2;
      if (e->expr_type == EXPR_VARIABLE
	  && e->symtree != NULL
	  && e->symtree->n.sym == var)
	v = e;
      else if ((c = is_conversion (e, true)) != NULL
	       && c->expr_type == EXPR_VARIABLE
	       && c->symtree != NULL
	       && c->symtree->n.sym == var)
	v = c;
      else
	{
	  gfc_expr **p = NULL, **q;
	  for (q = &expr2->value.op.op1; (e = *q) != NULL; )
	    if (e->expr_type == EXPR_VARIABLE
		&& e->symtree != NULL
		&& e->symtree->n.sym == var)
	      {
		v = e;
		break;
	      }
	    else if ((c = is_conversion (e, true)) != NULL)
	      q = &e->value.function.actual->expr;
	    else if (e->expr_type != EXPR_OP
		     || (e->value.op.op != op
			 && e->value.op.op != alt_op)
		     || e->rank != 0)
	      break;
	    else
	      {
		p = q;
		q = &e->value.op.op1;
	      }

	  if (v == NULL)
	    {
	      gfc_error ("!$OMP ATOMIC assignment must be var = var op expr "
			 "or var = expr op var at %L", &expr2->where);
	      return;
	    }

	  if (p != NULL)
	    {
	      e = *p;
	      switch (e->value.op.op)
		{
		case INTRINSIC_MINUS:
		case INTRINSIC_DIVIDE:
		case INTRINSIC_EQV:
		case INTRINSIC_NEQV:
		  gfc_error ("!$OMP ATOMIC var = var op expr not "
			     "mathematically equivalent to var = var op "
			     "(expr) at %L", &expr2->where);
		  break;
		default:
		  break;
		}

	      /* Canonicalize into var = var op (expr).  */
	      *p = e->value.op.op2;
	      e->value.op.op2 = expr2;
	      e->ts = expr2->ts;
	      if (code->expr2 == expr2)
		code->expr2 = expr2 = e;
	      else
		code->expr2->value.function.actual->expr = expr2 = e;

	      if (!gfc_compare_types (&expr2->value.op.op1->ts, &expr2->ts))
		{
		  for (p = &expr2->value.op.op1; *p != v;
		       p = &(*p)->value.function.actual->expr)
		    ;
		  *p = NULL;
		  gfc_free_expr (expr2->value.op.op1);
		  expr2->value.op.op1 = v;
		  gfc_convert_type (v, &expr2->ts, 2);
		}
	    }
	}

      if (e->rank != 0 || expr_references_sym (code->expr2, var, v))
	{
	  gfc_error ("expr in !$OMP ATOMIC assignment var = var op expr "
		     "must be scalar and cannot reference var at %L",
		     &expr2->where);
	  return;
	}
    }
  else if (expr2->expr_type == EXPR_FUNCTION
	   && expr2->value.function.isym != NULL
	   && expr2->value.function.esym == NULL
	   && expr2->value.function.actual != NULL
	   && expr2->value.function.actual->next != NULL)
    {
      gfc_actual_arglist *arg, *var_arg;

      switch (expr2->value.function.isym->id)
	{
	case GFC_ISYM_MIN:
	case GFC_ISYM_MAX:
	  break;
	case GFC_ISYM_IAND:
	case GFC_ISYM_IOR:
	case GFC_ISYM_IEOR:
	  if (expr2->value.function.actual->next->next != NULL)
	    {
	      gfc_error ("!$OMP ATOMIC assignment intrinsic IAND, IOR "
			 "or IEOR must have two arguments at %L",
			 &expr2->where);
	      return;
	    }
	  break;
	default:
	  gfc_error ("!$OMP ATOMIC assignment intrinsic must be "
		     "MIN, MAX, IAND, IOR or IEOR at %L",
		     &expr2->where);
	  return;
	}

      var_arg = NULL;
      for (arg = expr2->value.function.actual; arg; arg = arg->next)
	{
	  if ((arg == expr2->value.function.actual
	       || (var_arg == NULL && arg->next == NULL))
	      && arg->expr->expr_type == EXPR_VARIABLE
	      && arg->expr->symtree != NULL
	      && arg->expr->symtree->n.sym == var)
	    var_arg = arg;
	  else if (expr_references_sym (arg->expr, var, NULL))
	    {
	      gfc_error ("!$OMP ATOMIC intrinsic arguments except one must "
			 "not reference %qs at %L",
			 var->name, &arg->expr->where);
	      return;
	    }
	  if (arg->expr->rank != 0)
	    {
	      gfc_error ("!$OMP ATOMIC intrinsic arguments must be scalar "
			 "at %L", &arg->expr->where);
	      return;
	    }
	}

      if (var_arg == NULL)
	{
	  gfc_error ("First or last !$OMP ATOMIC intrinsic argument must "
		     "be %qs at %L", var->name, &expr2->where);
	  return;
	}

      if (var_arg != expr2->value.function.actual)
	{
	  /* Canonicalize, so that var comes first.  */
	  gcc_assert (var_arg->next == NULL);
	  for (arg = expr2->value.function.actual;
	       arg->next != var_arg; arg = arg->next)
	    ;
	  var_arg->next = expr2->value.function.actual;
	  expr2->value.function.actual = var_arg;
	  arg->next = NULL;
	}
    }
  else
    gfc_error ("!$OMP ATOMIC assignment must have an operator or "
	       "intrinsic on right hand side at %L", &expr2->where);

  if (atomic_code->ext.omp_clauses->capture && code->next)
    {
      code = code->next;
      if (code->expr1->expr_type != EXPR_VARIABLE
	  || code->expr1->symtree == NULL
	  || code->expr1->rank != 0
	  || (code->expr1->ts.type != BT_INTEGER
	      && code->expr1->ts.type != BT_REAL
	      && code->expr1->ts.type != BT_COMPLEX
	      && code->expr1->ts.type != BT_LOGICAL))
	{
	  gfc_error ("!$OMP ATOMIC CAPTURE capture statement must set "
		     "a scalar variable of intrinsic type at %L",
		     &code->expr1->where);
	  return;
	}

      expr2 = is_conversion (code->expr2, false);
      if (expr2 == NULL)
	{
	  expr2 = is_conversion (code->expr2, true);
	  if (expr2 == NULL)
	    expr2 = code->expr2;
	}

      if (expr2->expr_type != EXPR_VARIABLE
	  || expr2->symtree == NULL
	  || expr2->rank != 0
	  || (expr2->ts.type != BT_INTEGER
	      && expr2->ts.type != BT_REAL
	      && expr2->ts.type != BT_COMPLEX
	      && expr2->ts.type != BT_LOGICAL))
	{
	  gfc_error ("!$OMP ATOMIC CAPTURE capture statement must read "
		     "from a scalar variable of intrinsic type at %L",
		     &expr2->where);
	  return;
	}
      if (expr2->symtree->n.sym != var)
	{
	  gfc_error ("!$OMP ATOMIC CAPTURE capture statement reads from "
		     "different variable than update statement writes "
		     "into at %L", &expr2->where);
	  return;
	}
    }
}


static struct fortran_omp_context
{
  gfc_code *code;
  hash_set<gfc_symbol *> *sharing_clauses;
  hash_set<gfc_symbol *> *private_iterators;
  struct fortran_omp_context *previous;
  bool is_openmp;
} *omp_current_ctx;
static gfc_code *omp_current_do_code;
static int omp_current_do_collapse;

void
gfc_resolve_omp_do_blocks (gfc_code *code, gfc_namespace *ns)
{
  if (code->block->next && code->block->next->op == EXEC_DO)
    {
      int i;
      gfc_code *c;

      omp_current_do_code = code->block->next;
      if (code->ext.omp_clauses->orderedc)
	omp_current_do_collapse = code->ext.omp_clauses->orderedc;
      else
	omp_current_do_collapse = code->ext.omp_clauses->collapse;
      for (i = 1, c = omp_current_do_code; i < omp_current_do_collapse; i++)
	{
	  c = c->block;
	  if (c->op != EXEC_DO || c->next == NULL)
	    break;
	  c = c->next;
	  if (c->op != EXEC_DO)
	    break;
	}
      if (i < omp_current_do_collapse || omp_current_do_collapse <= 0)
	omp_current_do_collapse = 1;
      if (code->ext.omp_clauses->lists[OMP_LIST_REDUCTION_INSCAN])
	{
	  locus *loc
	    = &code->ext.omp_clauses->lists[OMP_LIST_REDUCTION_INSCAN]->where;
	  if (code->ext.omp_clauses->ordered)
	    gfc_error ("ORDERED clause specified together with %<inscan%> "
		       "REDUCTION clause at %L", loc);
	  if (code->ext.omp_clauses->sched_kind != OMP_SCHED_NONE)
	    gfc_error ("SCHEDULE clause specified together with %<inscan%> "
		       "REDUCTION clause at %L", loc);
	  if (!c->block
	      || !c->block->next
	      || !c->block->next->next
	      || c->block->next->next->op != EXEC_OMP_SCAN
	      || !c->block->next->next->next
	      || c->block->next->next->next->next)
	    gfc_error ("With INSCAN at %L, expected loop body with !$OMP SCAN "
		       "between two structured-block-sequences", loc);
	  else
	    /* Mark as checked; flag will be unset later.  */
	    c->block->next->next->ext.omp_clauses->if_present = true;
	}
    }
  gfc_resolve_blocks (code->block, ns);
  omp_current_do_collapse = 0;
  omp_current_do_code = NULL;
}


void
gfc_resolve_omp_parallel_blocks (gfc_code *code, gfc_namespace *ns)
{
  struct fortran_omp_context ctx;
  gfc_omp_clauses *omp_clauses = code->ext.omp_clauses;
  gfc_omp_namelist *n;
  int list;

  ctx.code = code;
  ctx.sharing_clauses = new hash_set<gfc_symbol *>;
  ctx.private_iterators = new hash_set<gfc_symbol *>;
  ctx.previous = omp_current_ctx;
  ctx.is_openmp = true;
  omp_current_ctx = &ctx;

  for (list = 0; list < OMP_LIST_NUM; list++)
    switch (list)
      {
      case OMP_LIST_SHARED:
      case OMP_LIST_PRIVATE:
      case OMP_LIST_FIRSTPRIVATE:
      case OMP_LIST_LASTPRIVATE:
      case OMP_LIST_REDUCTION:
      case OMP_LIST_REDUCTION_INSCAN:
      case OMP_LIST_REDUCTION_TASK:
      case OMP_LIST_IN_REDUCTION:
      case OMP_LIST_TASK_REDUCTION:
      case OMP_LIST_LINEAR:
	for (n = omp_clauses->lists[list]; n; n = n->next)
	  ctx.sharing_clauses->add (n->sym);
	break;
      default:
	break;
      }

  switch (code->op)
    {
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_PARALLEL_DO:
    case EXEC_OMP_PARALLEL_DO_SIMD:
    case EXEC_OMP_TARGET_PARALLEL_DO:
    case EXEC_OMP_TARGET_PARALLEL_DO_SIMD:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
    case EXEC_OMP_TASKLOOP:
    case EXEC_OMP_TASKLOOP_SIMD:
    case EXEC_OMP_TEAMS_DISTRIBUTE:
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_TEAMS_DISTRIBUTE_SIMD:
      gfc_resolve_omp_do_blocks (code, ns);
      break;
    default:
      gfc_resolve_blocks (code->block, ns);
    }

  omp_current_ctx = ctx.previous;
  delete ctx.sharing_clauses;
  delete ctx.private_iterators;
}


/* Save and clear openmp.c private state.  */

void
gfc_omp_save_and_clear_state (struct gfc_omp_saved_state *state)
{
  state->ptrs[0] = omp_current_ctx;
  state->ptrs[1] = omp_current_do_code;
  state->ints[0] = omp_current_do_collapse;
  omp_current_ctx = NULL;
  omp_current_do_code = NULL;
  omp_current_do_collapse = 0;
}


/* Restore openmp.c private state from the saved state.  */

void
gfc_omp_restore_state (struct gfc_omp_saved_state *state)
{
  omp_current_ctx = (struct fortran_omp_context *) state->ptrs[0];
  omp_current_do_code = (gfc_code *) state->ptrs[1];
  omp_current_do_collapse = state->ints[0];
}


/* Note a DO iterator variable.  This is special in !$omp parallel
   construct, where they are predetermined private.  */

void
gfc_resolve_do_iterator (gfc_code *code, gfc_symbol *sym, bool add_clause)
{
  if (omp_current_ctx == NULL)
    return;

  int i = omp_current_do_collapse;
  gfc_code *c = omp_current_do_code;

  if (sym->attr.threadprivate)
    return;

  /* !$omp do and !$omp parallel do iteration variable is predetermined
     private just in the !$omp do resp. !$omp parallel do construct,
     with no implications for the outer parallel constructs.  */

  while (i-- >= 1)
    {
      if (code == c)
	return;

      c = c->block->next;
    }

  /* An openacc context may represent a data clause.  Abort if so.  */
  if (!omp_current_ctx->is_openmp && !oacc_is_loop (omp_current_ctx->code))
    return;

  if (omp_current_ctx->sharing_clauses->contains (sym))
    return;

  if (! omp_current_ctx->private_iterators->add (sym) && add_clause)
    {
      gfc_omp_clauses *omp_clauses = omp_current_ctx->code->ext.omp_clauses;
      gfc_omp_namelist *p;

      p = gfc_get_omp_namelist ();
      p->sym = sym;
      p->next = omp_clauses->lists[OMP_LIST_PRIVATE];
      omp_clauses->lists[OMP_LIST_PRIVATE] = p;
    }
}

static void
handle_local_var (gfc_symbol *sym)
{
  if (sym->attr.flavor != FL_VARIABLE
      || sym->as != NULL
      || (sym->ts.type != BT_INTEGER && sym->ts.type != BT_REAL))
    return;
  gfc_resolve_do_iterator (sym->ns->code, sym, false);
}

void
gfc_resolve_omp_local_vars (gfc_namespace *ns)
{
  if (omp_current_ctx)
    gfc_traverse_ns (ns, handle_local_var);
}

static void
resolve_omp_do (gfc_code *code)
{
  gfc_code *do_code, *c;
  int list, i, collapse;
  gfc_omp_namelist *n;
  gfc_symbol *dovar;
  const char *name;
  bool is_simd = false;

  switch (code->op)
    {
    case EXEC_OMP_DISTRIBUTE: name = "!$OMP DISTRIBUTE"; break;
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO:
      name = "!$OMP DISTRIBUTE PARALLEL DO";
      break;
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD:
      name = "!$OMP DISTRIBUTE PARALLEL DO SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_DISTRIBUTE_SIMD:
      name = "!$OMP DISTRIBUTE SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_DO: name = "!$OMP DO"; break;
    case EXEC_OMP_DO_SIMD: name = "!$OMP DO SIMD"; is_simd = true; break;
    case EXEC_OMP_PARALLEL_DO: name = "!$OMP PARALLEL DO"; break;
    case EXEC_OMP_PARALLEL_DO_SIMD:
      name = "!$OMP PARALLEL DO SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_SIMD: name = "!$OMP SIMD"; is_simd = true; break;
    case EXEC_OMP_TARGET_PARALLEL_DO: name = "!$OMP TARGET PARALLEL DO"; break;
    case EXEC_OMP_TARGET_PARALLEL_DO_SIMD:
      name = "!$OMP TARGET PARALLEL DO SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TARGET_SIMD:
      name = "!$OMP TARGET SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE:
      name = "!$OMP TARGET TEAMS DISTRIBUTE";
      break;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
      name = "!$OMP TARGET TEAMS DISTRIBUTE PARALLEL DO";
      break;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
      name = "!$OMP TARGET TEAMS DISTRIBUTE PARALLEL DO SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
      name = "!$OMP TARGET TEAMS DISTRIBUTE SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TASKLOOP: name = "!$OMP TASKLOOP"; break;
    case EXEC_OMP_TASKLOOP_SIMD:
      name = "!$OMP TASKLOOP SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TEAMS_DISTRIBUTE: name = "!$OMP TEAMS DISTRIBUTE"; break;
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO:
      name = "!$OMP TEAMS DISTRIBUTE PARALLEL DO";
      break;
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
      name = "!$OMP TEAMS DISTRIBUTE PARALLEL DO SIMD";
      is_simd = true;
      break;
    case EXEC_OMP_TEAMS_DISTRIBUTE_SIMD:
      name = "!$OMP TEAMS DISTRIBUTE SIMD";
      is_simd = true;
      break;
    default: gcc_unreachable ();
    }

  if (code->ext.omp_clauses)
    resolve_omp_clauses (code, code->ext.omp_clauses, NULL);

  do_code = code->block->next;
  if (code->ext.omp_clauses->orderedc)
    collapse = code->ext.omp_clauses->orderedc;
  else
    {
      collapse = code->ext.omp_clauses->collapse;
      if (collapse <= 0)
	collapse = 1;
    }
  for (i = 1; i <= collapse; i++)
    {
      if (do_code->op == EXEC_DO_WHILE)
	{
	  gfc_error ("%s cannot be a DO WHILE or DO without loop control "
		     "at %L", name, &do_code->loc);
	  break;
	}
      if (do_code->op == EXEC_DO_CONCURRENT)
	{
	  gfc_error ("%s cannot be a DO CONCURRENT loop at %L", name,
		     &do_code->loc);
	  break;
	}
      gcc_assert (do_code->op == EXEC_DO);
      if (do_code->ext.iterator->var->ts.type != BT_INTEGER)
	gfc_error ("%s iteration variable must be of type integer at %L",
		   name, &do_code->loc);
      dovar = do_code->ext.iterator->var->symtree->n.sym;
      if (dovar->attr.threadprivate)
	gfc_error ("%s iteration variable must not be THREADPRIVATE "
		   "at %L", name, &do_code->loc);
      if (code->ext.omp_clauses)
	for (list = 0; list < OMP_LIST_NUM; list++)
	  if (!is_simd || code->ext.omp_clauses->collapse > 1
	      ? (list != OMP_LIST_PRIVATE && list != OMP_LIST_LASTPRIVATE)
	      : (list != OMP_LIST_PRIVATE && list != OMP_LIST_LASTPRIVATE
		 && list != OMP_LIST_LINEAR))
	    for (n = code->ext.omp_clauses->lists[list]; n; n = n->next)
	      if (dovar == n->sym)
		{
		  if (!is_simd || code->ext.omp_clauses->collapse > 1)
		    gfc_error ("%s iteration variable present on clause "
			       "other than PRIVATE or LASTPRIVATE at %L",
			       name, &do_code->loc);
		  else
		    gfc_error ("%s iteration variable present on clause "
			       "other than PRIVATE, LASTPRIVATE or "
			       "LINEAR at %L", name, &do_code->loc);
		  break;
		}
      if (i > 1)
	{
	  gfc_code *do_code2 = code->block->next;
	  int j;

	  for (j = 1; j < i; j++)
	    {
	      gfc_symbol *ivar = do_code2->ext.iterator->var->symtree->n.sym;
	      if (dovar == ivar
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->start)
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->end)
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->step))
		{
		  gfc_error ("%s collapsed loops don't form rectangular "
			     "iteration space at %L", name, &do_code->loc);
		  break;
		}
	      do_code2 = do_code2->block->next;
	    }
	}
      for (c = do_code->next; c; c = c->next)
	if (c->op != EXEC_NOP && c->op != EXEC_CONTINUE)
	  {
	    gfc_error ("collapsed %s loops not perfectly nested at %L",
		       name, &c->loc);
	    break;
	  }
      if (i == collapse || c)
	break;
      do_code = do_code->block;
      if (do_code->op != EXEC_DO && do_code->op != EXEC_DO_WHILE)
	{
	  gfc_error ("not enough DO loops for collapsed %s at %L",
		     name, &code->loc);
	  break;
	}
      do_code = do_code->next;
      if (do_code == NULL
	  || (do_code->op != EXEC_DO && do_code->op != EXEC_DO_WHILE))
	{
	  gfc_error ("not enough DO loops for collapsed %s at %L",
		     name, &code->loc);
	  break;
	}
    }
}


static gfc_statement
omp_code_to_statement (gfc_code *code)
{
  switch (code->op)
    {
    case EXEC_OMP_PARALLEL:
      return ST_OMP_PARALLEL;
    case EXEC_OMP_PARALLEL_SECTIONS:
      return ST_OMP_PARALLEL_SECTIONS;
    case EXEC_OMP_SECTIONS:
      return ST_OMP_SECTIONS;
    case EXEC_OMP_ORDERED:
      return ST_OMP_ORDERED;
    case EXEC_OMP_CRITICAL:
      return ST_OMP_CRITICAL;
    case EXEC_OMP_MASTER:
      return ST_OMP_MASTER;
    case EXEC_OMP_SINGLE:
      return ST_OMP_SINGLE;
    case EXEC_OMP_TASK:
      return ST_OMP_TASK;
    case EXEC_OMP_WORKSHARE:
      return ST_OMP_WORKSHARE;
    case EXEC_OMP_PARALLEL_WORKSHARE:
      return ST_OMP_PARALLEL_WORKSHARE;
    case EXEC_OMP_DO:
      return ST_OMP_DO;
    case EXEC_OMP_ATOMIC:
      return ST_OMP_ATOMIC;
    case EXEC_OMP_BARRIER:
      return ST_OMP_BARRIER;
    case EXEC_OMP_CANCEL:
      return ST_OMP_CANCEL;
    case EXEC_OMP_CANCELLATION_POINT:
      return ST_OMP_CANCELLATION_POINT;
    case EXEC_OMP_FLUSH:
      return ST_OMP_FLUSH;
    case EXEC_OMP_DISTRIBUTE:
      return ST_OMP_DISTRIBUTE;
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO:
      return ST_OMP_DISTRIBUTE_PARALLEL_DO;
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD:
      return ST_OMP_DISTRIBUTE_PARALLEL_DO_SIMD;
    case EXEC_OMP_DISTRIBUTE_SIMD:
      return ST_OMP_DISTRIBUTE_SIMD;
    case EXEC_OMP_DO_SIMD:
      return ST_OMP_DO_SIMD;
    case EXEC_OMP_SCAN:
      return ST_OMP_SCAN;
    case EXEC_OMP_SIMD:
      return ST_OMP_SIMD;
    case EXEC_OMP_TARGET:
      return ST_OMP_TARGET;
    case EXEC_OMP_TARGET_DATA:
      return ST_OMP_TARGET_DATA;
    case EXEC_OMP_TARGET_ENTER_DATA:
      return ST_OMP_TARGET_ENTER_DATA;
    case EXEC_OMP_TARGET_EXIT_DATA:
      return ST_OMP_TARGET_EXIT_DATA;
    case EXEC_OMP_TARGET_PARALLEL:
      return ST_OMP_TARGET_PARALLEL;
    case EXEC_OMP_TARGET_PARALLEL_DO:
      return ST_OMP_TARGET_PARALLEL_DO;
    case EXEC_OMP_TARGET_PARALLEL_DO_SIMD:
      return ST_OMP_TARGET_PARALLEL_DO_SIMD;
    case EXEC_OMP_TARGET_SIMD:
      return ST_OMP_TARGET_SIMD;
    case EXEC_OMP_TARGET_TEAMS:
      return ST_OMP_TARGET_TEAMS;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE:
      return ST_OMP_TARGET_TEAMS_DISTRIBUTE;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
      return ST_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
      return ST_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD;
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
      return ST_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD;
    case EXEC_OMP_TARGET_UPDATE:
      return ST_OMP_TARGET_UPDATE;
    case EXEC_OMP_TASKGROUP:
      return ST_OMP_TASKGROUP;
    case EXEC_OMP_TASKLOOP:
      return ST_OMP_TASKLOOP;
    case EXEC_OMP_TASKLOOP_SIMD:
      return ST_OMP_TASKLOOP_SIMD;
    case EXEC_OMP_TASKWAIT:
      return ST_OMP_TASKWAIT;
    case EXEC_OMP_TASKYIELD:
      return ST_OMP_TASKYIELD;
    case EXEC_OMP_TEAMS:
      return ST_OMP_TEAMS;
    case EXEC_OMP_TEAMS_DISTRIBUTE:
      return ST_OMP_TEAMS_DISTRIBUTE;
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO:
      return ST_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO;
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
      return ST_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD;
    case EXEC_OMP_TEAMS_DISTRIBUTE_SIMD:
      return ST_OMP_TEAMS_DISTRIBUTE_SIMD;
    case EXEC_OMP_PARALLEL_DO:
      return ST_OMP_PARALLEL_DO;
    case EXEC_OMP_PARALLEL_DO_SIMD:
      return ST_OMP_PARALLEL_DO_SIMD;

    default:
      gcc_unreachable ();
    }
}

static gfc_statement
oacc_code_to_statement (gfc_code *code)
{
  switch (code->op)
    {
    case EXEC_OACC_PARALLEL:
      return ST_OACC_PARALLEL;
    case EXEC_OACC_KERNELS:
      return ST_OACC_KERNELS;
    case EXEC_OACC_SERIAL:
      return ST_OACC_SERIAL;
    case EXEC_OACC_DATA:
      return ST_OACC_DATA;
    case EXEC_OACC_HOST_DATA:
      return ST_OACC_HOST_DATA;
    case EXEC_OACC_PARALLEL_LOOP:
      return ST_OACC_PARALLEL_LOOP;
    case EXEC_OACC_KERNELS_LOOP:
      return ST_OACC_KERNELS_LOOP;
    case EXEC_OACC_SERIAL_LOOP:
      return ST_OACC_SERIAL_LOOP;
    case EXEC_OACC_LOOP:
      return ST_OACC_LOOP;
    case EXEC_OACC_ATOMIC:
      return ST_OACC_ATOMIC;
    case EXEC_OACC_ROUTINE:
      return ST_OACC_ROUTINE;
    case EXEC_OACC_UPDATE:
      return ST_OACC_UPDATE;
    case EXEC_OACC_WAIT:
      return ST_OACC_WAIT;
    case EXEC_OACC_CACHE:
      return ST_OACC_CACHE;
    case EXEC_OACC_ENTER_DATA:
      return ST_OACC_ENTER_DATA;
    case EXEC_OACC_EXIT_DATA:
      return ST_OACC_EXIT_DATA;
    case EXEC_OACC_DECLARE:
      return ST_OACC_DECLARE;
    default:
      gcc_unreachable ();
    }
}

static void
resolve_oacc_directive_inside_omp_region (gfc_code *code)
{
  if (omp_current_ctx != NULL && omp_current_ctx->is_openmp)
    {
      gfc_statement st = omp_code_to_statement (omp_current_ctx->code);
      gfc_statement oacc_st = oacc_code_to_statement (code);
      gfc_error ("The %s directive cannot be specified within "
		 "a %s region at %L", gfc_ascii_statement (oacc_st), 
		 gfc_ascii_statement (st), &code->loc);
    }
}

static void
resolve_omp_directive_inside_oacc_region (gfc_code *code)
{
  if (omp_current_ctx != NULL && !omp_current_ctx->is_openmp)
    {
      gfc_statement st = oacc_code_to_statement (omp_current_ctx->code);
      gfc_statement omp_st = omp_code_to_statement (code);
      gfc_error ("The %s directive cannot be specified within "
		 "a %s region at %L", gfc_ascii_statement (omp_st), 
		 gfc_ascii_statement (st), &code->loc);
    }
}


static void
resolve_oacc_nested_loops (gfc_code *code, gfc_code* do_code, int collapse,
			  const char *clause)
{
  gfc_symbol *dovar;
  gfc_code *c;
  int i;

  for (i = 1; i <= collapse; i++)
    {
      if (do_code->op == EXEC_DO_WHILE)
	{
	  gfc_error ("!$ACC LOOP cannot be a DO WHILE or DO without loop control "
		     "at %L", &do_code->loc);
	  break;
	}
      if (do_code->op == EXEC_DO_CONCURRENT)
	{
	  gfc_error ("!$ACC LOOP cannot be a DO CONCURRENT loop at %L",
		     &do_code->loc);
	  break;
	}
      gcc_assert (do_code->op == EXEC_DO);
      if (do_code->ext.iterator->var->ts.type != BT_INTEGER)
	gfc_error ("!$ACC LOOP iteration variable must be of type integer at %L",
		   &do_code->loc);
      dovar = do_code->ext.iterator->var->symtree->n.sym;
      if (i > 1)
	{
	  gfc_code *do_code2 = code->block->next;
	  int j;

	  for (j = 1; j < i; j++)
	    {
	      gfc_symbol *ivar = do_code2->ext.iterator->var->symtree->n.sym;
	      if (dovar == ivar
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->start)
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->end)
		  || gfc_find_sym_in_expr (ivar, do_code->ext.iterator->step))
		{
		  gfc_error ("!$ACC LOOP %s loops don't form rectangular "
			     "iteration space at %L", clause, &do_code->loc);
		  break;
		}
	      do_code2 = do_code2->block->next;
	    }
	}
      if (i == collapse)
	break;
      for (c = do_code->next; c; c = c->next)
	if (c->op != EXEC_NOP && c->op != EXEC_CONTINUE)
	  {
	    gfc_error ("%s !$ACC LOOP loops not perfectly nested at %L",
		       clause, &c->loc);
	    break;
	  }
      if (c)
	break;
      do_code = do_code->block;
      if (do_code->op != EXEC_DO && do_code->op != EXEC_DO_WHILE
	  && do_code->op != EXEC_DO_CONCURRENT)
	{
	  gfc_error ("not enough DO loops for %s !$ACC LOOP at %L",
		     clause, &code->loc);
	  break;
	}
      do_code = do_code->next;
      if (do_code == NULL
	  || (do_code->op != EXEC_DO && do_code->op != EXEC_DO_WHILE
	      && do_code->op != EXEC_DO_CONCURRENT))
	{
	  gfc_error ("not enough DO loops for %s !$ACC LOOP at %L",
		     clause, &code->loc);
	  break;
	}
    }
}


static void
resolve_oacc_loop_blocks (gfc_code *code)
{
  if (!oacc_is_loop (code))
    return;

  if (code->ext.omp_clauses->tile_list && code->ext.omp_clauses->gang
      && code->ext.omp_clauses->worker && code->ext.omp_clauses->vector)
    gfc_error ("Tiled loop cannot be parallelized across gangs, workers and "
	       "vectors at the same time at %L", &code->loc);

  if (code->ext.omp_clauses->tile_list)
    {
      gfc_expr_list *el;
      for (el = code->ext.omp_clauses->tile_list; el; el = el->next)
	{
	  if (el->expr == NULL)
	    {
	      /* NULL expressions are used to represent '*' arguments.
		 Convert those to a 0 expressions.  */
	      el->expr = gfc_get_constant_expr (BT_INTEGER,
						gfc_default_integer_kind,
						&code->loc);
	      mpz_set_si (el->expr->value.integer, 0);
	    }
	  else
	    {
	      resolve_positive_int_expr (el->expr, "TILE");
	      if (el->expr->expr_type != EXPR_CONSTANT)
		gfc_error ("TILE requires constant expression at %L",
			   &code->loc);
	    }
	}
    }
}


void
gfc_resolve_oacc_blocks (gfc_code *code, gfc_namespace *ns)
{
  fortran_omp_context ctx;
  gfc_omp_clauses *omp_clauses = code->ext.omp_clauses;
  gfc_omp_namelist *n;
  int list;

  resolve_oacc_loop_blocks (code);

  ctx.code = code;
  ctx.sharing_clauses = new hash_set<gfc_symbol *>;
  ctx.private_iterators = new hash_set<gfc_symbol *>;
  ctx.previous = omp_current_ctx;
  ctx.is_openmp = false;
  omp_current_ctx = &ctx;

  for (list = 0; list < OMP_LIST_NUM; list++)
    switch (list)
      {
      case OMP_LIST_PRIVATE:
	for (n = omp_clauses->lists[list]; n; n = n->next)
	  ctx.sharing_clauses->add (n->sym);
	break;
      default:
	break;
      }

  gfc_resolve_blocks (code->block, ns);

  omp_current_ctx = ctx.previous;
  delete ctx.sharing_clauses;
  delete ctx.private_iterators;
}


static void
resolve_oacc_loop (gfc_code *code)
{
  gfc_code *do_code;
  int collapse;

  if (code->ext.omp_clauses)
    resolve_omp_clauses (code, code->ext.omp_clauses, NULL, true);

  do_code = code->block->next;
  collapse = code->ext.omp_clauses->collapse;

  /* Both collapsed and tiled loops are lowered the same way, but are not
     compatible.  In gfc_trans_omp_do, the tile is prioritized.  */
  if (code->ext.omp_clauses->tile_list)
    {
      int num = 0;
      gfc_expr_list *el;
      for (el = code->ext.omp_clauses->tile_list; el; el = el->next)
	++num;
      resolve_oacc_nested_loops (code, code->block->next, num, "tiled");
      return;
    }

  if (collapse <= 0)
    collapse = 1;
  resolve_oacc_nested_loops (code, do_code, collapse, "collapsed");
}

void
gfc_resolve_oacc_declare (gfc_namespace *ns)
{
  int list;
  gfc_omp_namelist *n;
  gfc_oacc_declare *oc;

  if (ns->oacc_declare == NULL)
    return;

  for (oc = ns->oacc_declare; oc; oc = oc->next)
    {
      for (list = 0; list < OMP_LIST_NUM; list++)
	for (n = oc->clauses->lists[list]; n; n = n->next)
	  {
	    n->sym->mark = 0;
	    if (n->sym->attr.flavor != FL_VARIABLE
		&& (n->sym->attr.flavor != FL_PROCEDURE
		    || n->sym->result != n->sym))
	      {
		gfc_error ("Object %qs is not a variable at %L",
			   n->sym->name, &oc->loc);
		continue;
	      }

	    if (n->expr && n->expr->ref->type == REF_ARRAY)
	      {
		gfc_error ("Array sections: %qs not allowed in"
			   " !$ACC DECLARE at %L", n->sym->name, &oc->loc);
		continue;
	      }
	  }

      for (n = oc->clauses->lists[OMP_LIST_DEVICE_RESIDENT]; n; n = n->next)
	check_array_not_assumed (n->sym, oc->loc, "DEVICE_RESIDENT");
    }

  for (oc = ns->oacc_declare; oc; oc = oc->next)
    {
      for (list = 0; list < OMP_LIST_NUM; list++)
	for (n = oc->clauses->lists[list]; n; n = n->next)
	  {
	    if (n->sym->mark)
	      {
		gfc_error ("Symbol %qs present on multiple clauses at %L",
			   n->sym->name, &oc->loc);
		continue;
	      }
	    else
	      n->sym->mark = 1;
	  }
    }

  for (oc = ns->oacc_declare; oc; oc = oc->next)
    {
      for (list = 0; list < OMP_LIST_NUM; list++)
	for (n = oc->clauses->lists[list]; n; n = n->next)
	  n->sym->mark = 0;
    }
}


void
gfc_resolve_oacc_routines (gfc_namespace *ns)
{
  for (gfc_oacc_routine_name *orn = ns->oacc_routine_names;
       orn;
       orn = orn->next)
    {
      gfc_symbol *sym = orn->sym;
      if (!sym->attr.external
	  && !sym->attr.function
	  && !sym->attr.subroutine)
	{
	  gfc_error ("NAME %qs does not refer to a subroutine or function"
		     " in !$ACC ROUTINE ( NAME ) at %L", sym->name, &orn->loc);
	  continue;
	}
      if (!gfc_add_omp_declare_target (&sym->attr, sym->name, &orn->loc))
	{
	  gfc_error ("NAME %qs invalid"
		     " in !$ACC ROUTINE ( NAME ) at %L", sym->name, &orn->loc);
	  continue;
	}
    }
}


void
gfc_resolve_oacc_directive (gfc_code *code, gfc_namespace *ns ATTRIBUTE_UNUSED)
{
  resolve_oacc_directive_inside_omp_region (code);

  switch (code->op)
    {
    case EXEC_OACC_PARALLEL:
    case EXEC_OACC_KERNELS:
    case EXEC_OACC_SERIAL:
    case EXEC_OACC_DATA:
    case EXEC_OACC_HOST_DATA:
    case EXEC_OACC_UPDATE:
    case EXEC_OACC_ENTER_DATA:
    case EXEC_OACC_EXIT_DATA:
    case EXEC_OACC_WAIT:
    case EXEC_OACC_CACHE:
      resolve_omp_clauses (code, code->ext.omp_clauses, NULL, true);
      break;
    case EXEC_OACC_PARALLEL_LOOP:
    case EXEC_OACC_KERNELS_LOOP:
    case EXEC_OACC_SERIAL_LOOP:
    case EXEC_OACC_LOOP:
      resolve_oacc_loop (code);
      break;
    case EXEC_OACC_ATOMIC:
      resolve_omp_atomic (code);
      break;
    default:
      break;
    }
}


/* Resolve OpenMP directive clauses and check various requirements
   of each directive.  */

void
gfc_resolve_omp_directive (gfc_code *code, gfc_namespace *ns)
{
  resolve_omp_directive_inside_oacc_region (code);

  if (code->op != EXEC_OMP_ATOMIC)
    gfc_maybe_initialize_eh ();

  switch (code->op)
    {
    case EXEC_OMP_DISTRIBUTE:
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_DISTRIBUTE_SIMD:
    case EXEC_OMP_DO:
    case EXEC_OMP_DO_SIMD:
    case EXEC_OMP_PARALLEL_DO:
    case EXEC_OMP_PARALLEL_DO_SIMD:
    case EXEC_OMP_SIMD:
    case EXEC_OMP_TARGET_PARALLEL_DO:
    case EXEC_OMP_TARGET_PARALLEL_DO_SIMD:
    case EXEC_OMP_TARGET_SIMD:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
    case EXEC_OMP_TASKLOOP:
    case EXEC_OMP_TASKLOOP_SIMD:
    case EXEC_OMP_TEAMS_DISTRIBUTE:
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO:
    case EXEC_OMP_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
    case EXEC_OMP_TEAMS_DISTRIBUTE_SIMD:
      resolve_omp_do (code);
      break;
    case EXEC_OMP_CANCEL:
    case EXEC_OMP_PARALLEL_WORKSHARE:
    case EXEC_OMP_PARALLEL:
    case EXEC_OMP_PARALLEL_SECTIONS:
    case EXEC_OMP_SECTIONS:
    case EXEC_OMP_SINGLE:
    case EXEC_OMP_TARGET:
    case EXEC_OMP_TARGET_DATA:
    case EXEC_OMP_TARGET_ENTER_DATA:
    case EXEC_OMP_TARGET_EXIT_DATA:
    case EXEC_OMP_TARGET_PARALLEL:
    case EXEC_OMP_TARGET_TEAMS:
    case EXEC_OMP_TASK:
    case EXEC_OMP_TEAMS:
    case EXEC_OMP_WORKSHARE:
      if (code->ext.omp_clauses)
	resolve_omp_clauses (code, code->ext.omp_clauses, NULL);
      break;
    case EXEC_OMP_TARGET_UPDATE:
      if (code->ext.omp_clauses)
	resolve_omp_clauses (code, code->ext.omp_clauses, NULL);
      if (code->ext.omp_clauses == NULL
	  || (code->ext.omp_clauses->lists[OMP_LIST_TO] == NULL
	      && code->ext.omp_clauses->lists[OMP_LIST_FROM] == NULL))
	gfc_error ("OMP TARGET UPDATE at %L requires at least one TO or "
		   "FROM clause", &code->loc);
      break;
    case EXEC_OMP_ATOMIC:
      resolve_omp_clauses (code, code->block->ext.omp_clauses, NULL);
      resolve_omp_atomic (code);
      break;
    case EXEC_OMP_CRITICAL:
      resolve_omp_clauses (code, code->ext.omp_clauses, NULL);
      if (!code->ext.omp_clauses->critical_name
	  && code->ext.omp_clauses->hint
	  && code->ext.omp_clauses->hint->ts.type == BT_INTEGER
	  && code->ext.omp_clauses->hint->expr_type == EXPR_CONSTANT
	  && mpz_sgn (code->ext.omp_clauses->hint->value.integer) != 0)
	gfc_error ("OMP CRITICAL at %L with HINT clause requires a NAME, "
		   "except when omp_sync_hint_none is used", &code->loc);
      break;
    case EXEC_OMP_SCAN:
      /* Flag is only used to checking, hence, it is unset afterwards.  */
      if (!code->ext.omp_clauses->if_present)
	gfc_error ("Unexpected !$OMP SCAN at %L outside loop construct with "
		   "%<inscan%> REDUCTION clause", &code->loc);
      code->ext.omp_clauses->if_present = false;
      resolve_omp_clauses (code, code->ext.omp_clauses, ns);
      break;
    default:
      break;
    }
}

/* Resolve !$omp declare simd constructs in NS.  */

void
gfc_resolve_omp_declare_simd (gfc_namespace *ns)
{
  gfc_omp_declare_simd *ods;

  for (ods = ns->omp_declare_simd; ods; ods = ods->next)
    {
      if (ods->proc_name != NULL
	  && ods->proc_name != ns->proc_name)
	gfc_error ("!$OMP DECLARE SIMD should refer to containing procedure "
		   "%qs at %L", ns->proc_name->name, &ods->where);
      if (ods->clauses)
	resolve_omp_clauses (NULL, ods->clauses, ns);
    }
}

struct omp_udr_callback_data
{
  gfc_omp_udr *omp_udr;
  bool is_initializer;
};

static int
omp_udr_callback (gfc_expr **e, int *walk_subtrees ATTRIBUTE_UNUSED,
		  void *data)
{
  struct omp_udr_callback_data *cd = (struct omp_udr_callback_data *) data;
  if ((*e)->expr_type == EXPR_VARIABLE)
    {
      if (cd->is_initializer)
	{
	  if ((*e)->symtree->n.sym != cd->omp_udr->omp_priv
	      && (*e)->symtree->n.sym != cd->omp_udr->omp_orig)
	    gfc_error ("Variable other than OMP_PRIV or OMP_ORIG used in "
		       "INITIALIZER clause of !$OMP DECLARE REDUCTION at %L",
		       &(*e)->where);
	}
      else
	{
	  if ((*e)->symtree->n.sym != cd->omp_udr->omp_out
	      && (*e)->symtree->n.sym != cd->omp_udr->omp_in)
	    gfc_error ("Variable other than OMP_OUT or OMP_IN used in "
		       "combiner of !$OMP DECLARE REDUCTION at %L",
		       &(*e)->where);
	}
    }
  return 0;
}

/* Resolve !$omp declare reduction constructs.  */

static void
gfc_resolve_omp_udr (gfc_omp_udr *omp_udr)
{
  gfc_actual_arglist *a;
  const char *predef_name = NULL;

  switch (omp_udr->rop)
    {
    case OMP_REDUCTION_PLUS:
    case OMP_REDUCTION_TIMES:
    case OMP_REDUCTION_MINUS:
    case OMP_REDUCTION_AND:
    case OMP_REDUCTION_OR:
    case OMP_REDUCTION_EQV:
    case OMP_REDUCTION_NEQV:
    case OMP_REDUCTION_MAX:
    case OMP_REDUCTION_USER:
      break;
    default:
      gfc_error ("Invalid operator for !$OMP DECLARE REDUCTION %s at %L",
		 omp_udr->name, &omp_udr->where);
      return;
    }

  if (gfc_omp_udr_predef (omp_udr->rop, omp_udr->name,
			  &omp_udr->ts, &predef_name))
    {
      if (predef_name)
	gfc_error_now ("Redefinition of predefined %s "
		       "!$OMP DECLARE REDUCTION at %L",
		       predef_name, &omp_udr->where);
      else
	gfc_error_now ("Redefinition of predefined "
		       "!$OMP DECLARE REDUCTION at %L", &omp_udr->where);
      return;
    }

  if (omp_udr->ts.type == BT_CHARACTER
      && omp_udr->ts.u.cl->length
      && omp_udr->ts.u.cl->length->expr_type != EXPR_CONSTANT)
    {
      gfc_error ("CHARACTER length in !$OMP DECLARE REDUCTION %s not "
		 "constant at %L", omp_udr->name, &omp_udr->where);
      return;
    }

  struct omp_udr_callback_data cd;
  cd.omp_udr = omp_udr;
  cd.is_initializer = false;
  gfc_code_walker (&omp_udr->combiner_ns->code, gfc_dummy_code_callback,
		   omp_udr_callback, &cd);
  if (omp_udr->combiner_ns->code->op == EXEC_CALL)
    {
      for (a = omp_udr->combiner_ns->code->ext.actual; a; a = a->next)
	if (a->expr == NULL)
	  break;
      if (a)
	gfc_error ("Subroutine call with alternate returns in combiner "
		   "of !$OMP DECLARE REDUCTION at %L",
		   &omp_udr->combiner_ns->code->loc);
    }
  if (omp_udr->initializer_ns)
    {
      cd.is_initializer = true;
      gfc_code_walker (&omp_udr->initializer_ns->code, gfc_dummy_code_callback,
		       omp_udr_callback, &cd);
      if (omp_udr->initializer_ns->code->op == EXEC_CALL)
	{
	  for (a = omp_udr->initializer_ns->code->ext.actual; a; a = a->next)
	    if (a->expr == NULL)
	      break;
	  if (a)
	    gfc_error ("Subroutine call with alternate returns in "
		       "INITIALIZER clause of !$OMP DECLARE REDUCTION "
		       "at %L", &omp_udr->initializer_ns->code->loc);
	  for (a = omp_udr->initializer_ns->code->ext.actual; a; a = a->next)
	    if (a->expr
		&& a->expr->expr_type == EXPR_VARIABLE
		&& a->expr->symtree->n.sym == omp_udr->omp_priv
		&& a->expr->ref == NULL)
	      break;
	  if (a == NULL)
	    gfc_error ("One of actual subroutine arguments in INITIALIZER "
		       "clause of !$OMP DECLARE REDUCTION must be OMP_PRIV "
		       "at %L", &omp_udr->initializer_ns->code->loc);
	}
    }
  else if (omp_udr->ts.type == BT_DERIVED
	   && !gfc_has_default_initializer (omp_udr->ts.u.derived))
    {
      gfc_error ("Missing INITIALIZER clause for !$OMP DECLARE REDUCTION "
		 "of derived type without default initializer at %L",
		 &omp_udr->where);
      return;
    }
}

void
gfc_resolve_omp_udrs (gfc_symtree *st)
{
  gfc_omp_udr *omp_udr;

  if (st == NULL)
    return;
  gfc_resolve_omp_udrs (st->left);
  gfc_resolve_omp_udrs (st->right);
  for (omp_udr = st->n.omp_udr; omp_udr; omp_udr = omp_udr->next)
    gfc_resolve_omp_udr (omp_udr);
}