diff mbox

[2/6,GOMP4] OpenACC 1.0+ support in fortran front-end

Message ID 52E1597E.8070809@samsung.com
State New
Headers show

Commit Message

Ilmir Usmanov Jan. 23, 2014, 6:03 p.m. UTC

Comments

Thomas Schwinge Jan. 24, 2014, 8:47 p.m. UTC | #1
Hi!

Regarding my comments, please keep in mind that I don't have a lot of
Fortran experience; neither as a user nor as an implementor ;-) in the
GCC front end, so don't hesitate to tell me if I'm misunderstanding
something.  As I suggested, it may make sense to CC Fortran front end
maintainers for such patches.


On Thu, 23 Jan 2014 22:03:42 +0400, Ilmir Usmanov <i.usmanov@samsung.com> wrote:
> Subject: [PATCH 2/6] OpenACC fortran FE part 2

> --- a/gcc/fortran/openmp.c
> +++ b/gcc/fortran/openmp.c

> @@ -186,15 +292,51 @@ cleanup:
>  #define OMP_CLAUSE_FINAL	(1 << 14)
>  #define OMP_CLAUSE_MERGEABLE	(1 << 15)
>  
> +/* OpenACC 2.0 clauses. */
> +#define OACC_CLAUSE_IF                   OMP_CLAUSE_IF
> +#define OACC_CLAUSE_ASYNC                (1 << 16)
> +#define OACC_CLAUSE_NUM_GANGS            (1 << 17)
> +#define OACC_CLAUSE_NUM_WORKERS          (1 << 18)
> +#define OACC_CLAUSE_VECTOR_LENGTH        (1 << 19)
> +#define OACC_CLAUSE_REDUCTION            OMP_CLAUSE_REDUCTION
> +#define OACC_CLAUSE_COPY                 (1 << 20)
> +#define OACC_CLAUSE_COPYIN               OMP_CLAUSE_COPYIN
> +#define OACC_CLAUSE_COPYOUT              (1 << 21)
> +#define OACC_CLAUSE_[...]

As asked/suggested in »[PATCH 4/6] OpenACC GENERIC nodes«, can we again
avoid the duplicate names, and use the existing OpenMP memory mapping
stuff for expressing the OpenACC data clauses?

>  /* Match OpenMP 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, int mask)
> +gfc_match_omp_clauses (gfc_omp_clauses **cp, long long mask, bool is_acc)

Here, in turn, in the C front end,
<http://news.gmane.org/find-root.php?message_id=%3C1389712208-416-4-git-send-email-thomas%40codesourcery.com%3E>
(and following), I went with a separate function for OpenACC vs. OpenMP
clauses parsing, specifically to avoid the is_acc disambiguation
variable.

That is, I parse the OACC_CLAUSE_* in context of either an OpenACC or
OpenMP directive, and as such it's implicitly clear whether this is an
OpenACC or OpenMP one.

That's the reason why I can have PRAGMA_OMP_CLAUSE_COPYIN mean different
things for OpenACC vs. OpenMP in the C front end.  Maybe such an approach
would work well in the Fortran front end, too?


Grüße,
 Thomas
diff mbox

Patch

From 69bf2531e4512b7cdb2feba8541de1eaf9c2aa56 Mon Sep 17 00:00:00 2001
From: Ilmir Usmanov <i.usmanov@samsung.com>
Date: Thu, 23 Jan 2014 21:05:11 +0400
Subject: [PATCH 2/6] OpenACC fortran FE part 2

---
 gcc/fortran/openmp.c | 1032 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 1019 insertions(+), 13 deletions(-)

diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c
index 6c4dccb..ce13e52 100644
--- a/gcc/fortran/openmp.c
+++ b/gcc/fortran/openmp.c
@@ -69,11 +69,36 @@  gfc_free_omp_clauses (gfc_omp_clauses *c)
   gfc_free_expr (c->final_expr);
   gfc_free_expr (c->num_threads);
   gfc_free_expr (c->chunk_size);
-  for (i = 0; i < OMP_LIST_NUM; i++)
+  gfc_free_expr (c->async_expr);
+  gfc_free_expr (c->gang_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);
+  gfc_free_expr (c->non_clause_wait_expr);
+
+  for (i = 0; i < OACC_LIST_NUM; i++)
     gfc_free_namelist (c->lists[i]);
+
+  gfc_free_exprlist (c->waitlist);
+
   free (c);
 }
 
+/* Free expression list. */
+void
+gfc_free_exprlist (gfc_exprlist *list)
+{
+  gfc_exprlist *n;
+
+  for (; list; list = n)
+    {
+      n = list->next;
+      free (list);
+    }
+}
+
 /* Match a variable/common block list and construct a namelist from it.  */
 
 static match
@@ -169,6 +194,87 @@  cleanup:
   return MATCH_ERROR;
 }
 
+static match
+match_oacc_exprlist (const char *str, gfc_exprlist **list, bool allow_asterisk)
+{
+  gfc_exprlist *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_exprlist ();
+          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_exprlist (head);
+  gfc_current_locus = old_loc;
+  return MATCH_ERROR;
+}
+
+static match
+match_oacc_clause_gang (gfc_oacc_clauses *cp)
+{
+  if (gfc_match_char ('(') != MATCH_YES)
+    return MATCH_NO;
+  if (gfc_match (" num :") == MATCH_YES)
+    {
+      cp->gang_static = false;
+      return gfc_match (" %e )", &cp->gang_expr);
+    }
+  if (gfc_match (" static :") == MATCH_YES)
+    {
+      cp->gang_static = true;
+      if (gfc_match (" * )") != MATCH_YES)
+        return gfc_match (" %e )", &cp->gang_expr);
+      return MATCH_YES;
+    }
+  return gfc_match (" %e )", &cp->gang_expr);
+}
+
 #define OMP_CLAUSE_PRIVATE	(1 << 0)
 #define OMP_CLAUSE_FIRSTPRIVATE	(1 << 1)
 #define OMP_CLAUSE_LASTPRIVATE	(1 << 2)
@@ -186,15 +292,51 @@  cleanup:
 #define OMP_CLAUSE_FINAL	(1 << 14)
 #define OMP_CLAUSE_MERGEABLE	(1 << 15)
 
+/* OpenACC 2.0 clauses. */
+#define OACC_CLAUSE_IF                   OMP_CLAUSE_IF
+#define OACC_CLAUSE_ASYNC                (1 << 16)
+#define OACC_CLAUSE_NUM_GANGS            (1 << 17)
+#define OACC_CLAUSE_NUM_WORKERS          (1 << 18)
+#define OACC_CLAUSE_VECTOR_LENGTH        (1 << 19)
+#define OACC_CLAUSE_REDUCTION            OMP_CLAUSE_REDUCTION
+#define OACC_CLAUSE_COPY                 (1 << 20)
+#define OACC_CLAUSE_COPYIN               OMP_CLAUSE_COPYIN
+#define OACC_CLAUSE_COPYOUT              (1 << 21)
+#define OACC_CLAUSE_CREATE               (1 << 22)
+#define OACC_CLAUSE_PRESENT              (1 << 23)
+#define OACC_CLAUSE_PRESENT_OR_COPY      (1 << 24)
+#define OACC_CLAUSE_PRESENT_OR_COPYIN    (1 << 25)
+#define OACC_CLAUSE_PRESENT_OR_COPYOUT   (1 << 26)
+#define OACC_CLAUSE_PRESENT_OR_CREATE    (1 << 27)
+#define OACC_CLAUSE_DEVICEPTR            (1 << 28)
+#define OACC_CLAUSE_PRIVATE              OMP_CLAUSE_PRIVATE
+#define OACC_CLAUSE_FIRSTPRIVATE         OMP_CLAUSE_FIRSTPRIVATE
+#define OACC_CLAUSE_COLLAPSE             OMP_CLAUSE_COLLAPSE
+#define OACC_CLAUSE_GANG                 (1 << 29)
+#define OACC_CLAUSE_WORKER               (1 << 30)
+#define OACC_CLAUSE_VECTOR               (1 << 31)
+#define OACC_CLAUSE_SEQ                  (1ll << 32)
+#define OACC_CLAUSE_INDEPENDENT          (1ll << 33)
+#define OACC_CLAUSE_USE_DEVICE           (1ll << 34)
+#define OACC_CLAUSE_DEVICE_RESIDENT      (1ll << 35)
+#define OACC_CLAUSE_HOST                 (1ll << 36)
+#define OACC_CLAUSE_DEVICE               (1ll << 37)
+#define OACC_CLAUSE_DEFAULT              (1ll << 38)
+#define OACC_CLAUSE_WAIT                 (1ll << 39)
+#define OACC_CLAUSE_DELETE               (1ll << 40)
+#define OACC_CLAUSE_AUTO                 (1ll << 41)
+#define OACC_CLAUSE_TILE                 (1ll << 42)
+
 /* Match OpenMP 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, int mask)
+gfc_match_omp_clauses (gfc_omp_clauses **cp, long long mask, bool is_acc)
 {
   gfc_omp_clauses *c = gfc_get_omp_clauses ();
   locus old_loc;
   bool needs_space = true, first = true;
+  c->is_acc = is_acc;
 
   *cp = NULL;
   while (1)
@@ -205,6 +347,52 @@  gfc_match_omp_clauses (gfc_omp_clauses **cp, int mask)
       needs_space = false;
       first = false;
       gfc_gobble_whitespace ();
+      if ((mask & OACC_CLAUSE_ASYNC) && !c->async)
+        if (gfc_match ("async") == MATCH_YES)
+          {
+            c->async = true;
+            if (gfc_match (" ( %e )", &c->async_expr) == MATCH_YES)
+              needs_space = false;
+            else
+              needs_space = true;
+            continue;
+          }
+      if ((mask & OACC_CLAUSE_GANG) && !c->gang)
+        if (gfc_match ("gang") == MATCH_YES)
+          {
+            c->gang = true;
+            if (match_oacc_clause_gang(c) == MATCH_YES)
+              needs_space = false;
+            else
+              needs_space = true;
+            continue;
+          }
+      if ((mask & OACC_CLAUSE_WORKER) && !c->worker)
+        if (gfc_match ("worker") == MATCH_YES)
+          {
+            c->worker = true;
+            if (gfc_match (" ( num : %e )", &c->worker_expr) == MATCH_YES
+                || gfc_match (" ( %e )", &c->worker_expr) == MATCH_YES)
+              needs_space = false;
+            else
+              needs_space = true;
+            continue;
+          }
+      if ((mask & OACC_CLAUSE_VECTOR_LENGTH) && c->vector_length_expr == NULL
+          && gfc_match ("vector_length ( %e )", &c->vector_length_expr)
+          == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_VECTOR) && !c->vector)
+        if (gfc_match ("vector") == MATCH_YES)
+          {
+            c->vector = true;
+            if (gfc_match (" ( length : %e )", &c->vector_expr) == MATCH_YES
+                || gfc_match (" ( %e )", &c->vector_expr) == MATCH_YES)
+              needs_space = false;
+            else
+              needs_space = true;
+            continue;
+          }
       if ((mask & OMP_CLAUSE_IF) && c->if_expr == NULL
 	  && gfc_match ("if ( %e )", &c->if_expr) == MATCH_YES)
 	continue;
@@ -242,11 +430,157 @@  gfc_match_omp_clauses (gfc_omp_clauses **cp, int mask)
 					  &c->lists[OMP_LIST_SHARED], true)
 	     == MATCH_YES)
 	continue;
-      if ((mask & OMP_CLAUSE_COPYIN)
+      if (!c->is_acc && (mask & OMP_CLAUSE_COPYIN)
 	  && gfc_match_omp_variable_list ("copyin (",
 					  &c->lists[OMP_LIST_COPYIN], true)
 	     == MATCH_YES)
 	continue;
+      if (c->is_acc && (mask & OACC_CLAUSE_COPYIN)
+          && gfc_match_omp_variable_list ("copyin (",
+                                          &c->lists[OACC_LIST_COPYIN], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_NUM_GANGS) && c->num_gangs_expr == NULL
+          && gfc_match ("num_gangs ( %e )", &c->num_gangs_expr) == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_NUM_WORKERS) && c->num_workers_expr == NULL
+          && gfc_match ("num_workers ( %e )", &c->num_workers_expr)
+          == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_COPY)
+          && gfc_match_omp_variable_list ("copy (",
+                                      &c->lists[OACC_LIST_COPY], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_COPYOUT)
+          && gfc_match_omp_variable_list ("copyout (",
+                                      &c->lists[OACC_LIST_COPYOUT], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_CREATE)
+          && gfc_match_omp_variable_list ("create (",
+                                      &c->lists[OACC_LIST_CREATE], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_DELETE)
+          && gfc_match_omp_variable_list ("delete (",
+                                      &c->lists[OACC_LIST_DELETE], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT)
+          && gfc_match_omp_variable_list ("present (",
+                                      &c->lists[OACC_LIST_PRESENT], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPY)
+          && gfc_match_omp_variable_list ("present_or_copy (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPY], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPY)
+          && gfc_match_omp_variable_list ("pcopy (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPY], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPYIN)
+          && gfc_match_omp_variable_list ("present_or_copyin (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPYIN],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPYIN)
+          && gfc_match_omp_variable_list ("pcopyin (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPYIN],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPYOUT)
+          && gfc_match_omp_variable_list ("present_or_copyout (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPYOUT],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_COPYOUT)
+          && gfc_match_omp_variable_list ("pcopyout (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_COPYOUT],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_CREATE)
+          && gfc_match_omp_variable_list ("present_or_create (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_CREATE],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_PRESENT_OR_CREATE)
+          && gfc_match_omp_variable_list ("pcreate (",
+                                      &c->lists[OACC_LIST_PRESENT_OR_CREATE],
+                                      true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_DEVICEPTR)
+          && gfc_match_omp_variable_list ("deviceptr (",
+                                      &c->lists[OACC_LIST_DEVICEPTR], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_USE_DEVICE)
+          && gfc_match_omp_variable_list ("use_device (",
+                                      &c->lists[OACC_LIST_USE_DEVICE], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_DEVICE_RESIDENT)
+          && gfc_match_omp_variable_list ("device_resident (",
+                                      &c->lists[OACC_LIST_DEVICE_RESIDENT], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_HOST)
+          && gfc_match_omp_variable_list ("host (",
+                                      &c->lists[OACC_LIST_HOST], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_DEVICE)
+          && gfc_match_omp_variable_list ("device (",
+                                      &c->lists[OACC_LIST_DEVICE], true)
+             == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_TILE)
+          && match_oacc_exprlist ("tile (", &c->tilelist, true) == MATCH_YES)
+        continue;
+      if ((mask & OACC_CLAUSE_SEQ) && !c->seq
+          && gfc_match ("seq") == MATCH_YES)
+        {
+          c->seq = true;
+          needs_space = true;
+          continue;
+        }
+      if ((mask & OACC_CLAUSE_INDEPENDENT) && !c->independent
+          && gfc_match ("independent") == MATCH_YES)
+        {
+          c->independent = true;
+          needs_space = true;
+          continue;
+        }
+      if ((mask & OACC_CLAUSE_DEFAULT) && !c->default_none
+                && gfc_match ("default ( none )") == MATCH_YES)
+        {
+          c->default_none = true;
+          needs_space = true;
+          continue;
+        }
+      if ((mask & OACC_CLAUSE_AUTO) && !c->par_auto
+                && gfc_match ("auto") == MATCH_YES)
+        {
+          c->par_auto = true;
+          needs_space = true;
+          continue;
+        }
+      if ((mask & OACC_CLAUSE_WAIT) && !c->wait
+                && gfc_match ("wait") == MATCH_YES)
+        {
+          c->wait = true;
+          match_oacc_exprlist (" (", &c->waitlist, false);
+          continue;
+        }
       old_loc = gfc_current_locus;
       if ((mask & OMP_CLAUSE_REDUCTION)
 	  && gfc_match ("reduction ( ") == MATCH_YES)
@@ -433,6 +767,51 @@  gfc_match_omp_clauses (gfc_omp_clauses **cp, int mask)
   return MATCH_YES;
 }
 
+#define OACC_PARALLEL_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_ASYNC | OACC_CLAUSE_NUM_GANGS                    \
+   | OACC_CLAUSE_NUM_WORKERS | OACC_CLAUSE_VECTOR_LENGTH | OACC_CLAUSE_REDUCTION \
+   | OACC_CLAUSE_COPY | OACC_CLAUSE_COPYIN | OACC_CLAUSE_COPYOUT                 \
+   | OACC_CLAUSE_CREATE | OACC_CLAUSE_PRESENT | OACC_CLAUSE_PRESENT_OR_COPY      \
+   | OACC_CLAUSE_PRESENT_OR_COPYIN | OACC_CLAUSE_PRESENT_OR_COPYOUT             \
+   | OACC_CLAUSE_PRESENT_OR_CREATE | OACC_CLAUSE_DEVICEPTR | OACC_CLAUSE_PRIVATE \
+   | OACC_CLAUSE_FIRSTPRIVATE | OACC_CLAUSE_DEFAULT | OACC_CLAUSE_WAIT)
+#define OACC_KERNELS_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_ASYNC | OACC_CLAUSE_DEVICEPTR                    \
+   | OACC_CLAUSE_COPY | OACC_CLAUSE_COPYIN | OACC_CLAUSE_COPYOUT                 \
+   | OACC_CLAUSE_CREATE | OACC_CLAUSE_PRESENT | OACC_CLAUSE_PRESENT_OR_COPY      \
+   | OACC_CLAUSE_PRESENT_OR_COPYIN | OACC_CLAUSE_PRESENT_OR_COPYOUT             \
+   | OACC_CLAUSE_PRESENT_OR_CREATE | OACC_CLAUSE_DEFAULT | OACC_CLAUSE_WAIT)
+#define OACC_DATA_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_DEVICEPTR  | OACC_CLAUSE_COPY | OACC_CLAUSE_COPYIN \
+   | OACC_CLAUSE_COPYOUT | OACC_CLAUSE_CREATE | OACC_CLAUSE_PRESENT               \
+   | OACC_CLAUSE_PRESENT_OR_COPY | OACC_CLAUSE_PRESENT_OR_COPYIN                 \
+   | OACC_CLAUSE_PRESENT_OR_COPYOUT | OACC_CLAUSE_PRESENT_OR_CREATE)
+#define OACC_LOOP_CLAUSES \
+  (OACC_CLAUSE_COLLAPSE | OACC_CLAUSE_GANG | OACC_CLAUSE_WORKER     \
+   | OACC_CLAUSE_VECTOR | OACC_CLAUSE_SEQ | OACC_CLAUSE_INDEPENDENT \
+   | OACC_CLAUSE_PRIVATE | OACC_CLAUSE_REDUCTION | OACC_CLAUSE_AUTO \
+   | OACC_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_HOST_DATA_CLAUSES OACC_CLAUSE_USE_DEVICE
+#define OACC_DECLARE_CLAUSES \
+  (OACC_CLAUSE_COPY | OACC_CLAUSE_COPYIN | OACC_CLAUSE_COPYOUT                \
+   | OACC_CLAUSE_CREATE | OACC_CLAUSE_DEVICEPTR | OACC_CLAUSE_DEVICE_RESIDENT \
+   | OACC_CLAUSE_PRESENT | OACC_CLAUSE_PRESENT_OR_COPY                       \
+   | OACC_CLAUSE_PRESENT_OR_COPYIN | OACC_CLAUSE_PRESENT_OR_COPYOUT          \
+   | OACC_CLAUSE_PRESENT_OR_CREATE)
+#define OACC_UPDATE_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_ASYNC | OACC_CLAUSE_HOST | OACC_CLAUSE_DEVICE)
+#define OACC_ENTER_DATA_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_ASYNC | OACC_CLAUSE_WAIT | OACC_CLAUSE_COPYIN \
+   | OACC_CLAUSE_CREATE | OACC_CLAUSE_PRESENT_OR_COPYIN                     \
+   | OACC_CLAUSE_PRESENT_OR_CREATE)
+#define OACC_EXIT_DATA_CLAUSES \
+  (OACC_CLAUSE_IF | OACC_CLAUSE_ASYNC | OACC_CLAUSE_WAIT | OACC_CLAUSE_COPYOUT \
+   | OACC_CLAUSE_DELETE)
+
 #define OMP_PARALLEL_CLAUSES \
   (OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE | OMP_CLAUSE_SHARED	\
    | OMP_CLAUSE_COPYIN | OMP_CLAUSE_REDUCTION | OMP_CLAUSE_IF		\
@@ -449,11 +828,190 @@  gfc_match_omp_clauses (gfc_omp_clauses **cp, int mask)
    | OMP_CLAUSE_IF | OMP_CLAUSE_DEFAULT | OMP_CLAUSE_UNTIED		\
    | OMP_CLAUSE_FINAL | OMP_CLAUSE_MERGEABLE)
 
+
+match
+gfc_match_oacc_parallel_loop (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_PARALLEL_LOOP_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_PARALLEL_LOOP;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_parallel (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_PARALLEL_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_PARALLEL;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_kernels_loop (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_KERNELS_LOOP_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_KERNELS_LOOP;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_kernels (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_KERNELS_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_KERNELS;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_data (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_DATA_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_DATA;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_host_data (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_HOST_DATA_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_HOST_DATA;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_loop (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_LOOP_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_LOOP;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_declare (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_DECLARE_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_update (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_UPDATE_CLAUSES, true) != MATCH_YES)
+    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)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_ENTER_DATA_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_ENTER_DATA;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_exit_data (void)
+{
+  gfc_oacc_clauses *c;
+  if (gfc_match_omp_clauses (&c, OACC_EXIT_DATA_CLAUSES, true) != MATCH_YES)
+    return MATCH_ERROR;
+
+  new_st.op = EXEC_OACC_EXIT_DATA;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_wait (void)
+{
+  gfc_oacc_clauses *c = gfc_get_oacc_clauses ();
+  gfc_match (" ( %e )", &c->non_clause_wait_expr);
+
+  new_st.op = EXEC_OACC_WAIT;
+  new_st.ext.omp_clauses = c;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_oacc_cache (void)
+{
+  gfc_oacc_clauses *c = gfc_get_oacc_clauses ();
+  match m = gfc_match_omp_variable_list (" (",&c->lists[OACC_LIST_CACHE], true);
+  if (m != MATCH_YES)
+    {
+      gfc_free_omp_clauses(c);
+      return m;
+    }
+
+  if (gfc_current_state() != COMP_DO)
+    {
+      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;
+}
+
+
 match
 gfc_match_omp_parallel (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_PARALLEL;
   new_st.ext.omp_clauses = c;
@@ -465,7 +1023,7 @@  match
 gfc_match_omp_task (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_TASK_CLAUSES) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_TASK_CLAUSES, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_TASK;
   new_st.ext.omp_clauses = c;
@@ -523,7 +1081,7 @@  match
 gfc_match_omp_do (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_DO_CLAUSES) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_DO_CLAUSES, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_DO;
   new_st.ext.omp_clauses = c;
@@ -620,7 +1178,7 @@  match
 gfc_match_omp_parallel_do (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES)
+  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES | OMP_DO_CLAUSES, false)
       != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_PARALLEL_DO;
@@ -633,7 +1191,8 @@  match
 gfc_match_omp_parallel_sections (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES | OMP_SECTIONS_CLAUSES)
+  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES | OMP_SECTIONS_CLAUSES, 
+  							 false)
       != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_PARALLEL_SECTIONS;
@@ -646,7 +1205,7 @@  match
 gfc_match_omp_parallel_workshare (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_PARALLEL_CLAUSES, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_PARALLEL_WORKSHARE;
   new_st.ext.omp_clauses = c;
@@ -658,7 +1217,7 @@  match
 gfc_match_omp_sections (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_SECTIONS_CLAUSES) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_SECTIONS_CLAUSES, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_SECTIONS;
   new_st.ext.omp_clauses = c;
@@ -670,7 +1229,8 @@  match
 gfc_match_omp_single (void)
 {
   gfc_omp_clauses *c;
-  if (gfc_match_omp_clauses (&c, OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE)
+  if (gfc_match_omp_clauses (&c, OMP_CLAUSE_PRIVATE | OMP_CLAUSE_FIRSTPRIVATE, 
+  							 false)
       != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_SINGLE;
@@ -785,7 +1345,7 @@  gfc_match_omp_end_single (void)
       new_st.ext.omp_bool = true;
       return MATCH_YES;
     }
-  if (gfc_match_omp_clauses (&c, OMP_CLAUSE_COPYPRIVATE) != MATCH_YES)
+  if (gfc_match_omp_clauses (&c, OMP_CLAUSE_COPYPRIVATE, false) != MATCH_YES)
     return MATCH_ERROR;
   new_st.op = EXEC_OMP_END_SINGLE;
   new_st.ext.omp_clauses = c;
@@ -793,6 +1353,27 @@  gfc_match_omp_end_single (void)
 }
 
 
+static void
+resolve_oacc_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_oacc_positive_int_expr (gfc_expr *expr, const char *clause)
+{
+  resolve_oacc_scalar_int_expr (expr, clause);
+  if (expr->expr_type == EXPR_CONSTANT && expr->ts.type == BT_INTEGER
+      && expr->value.integer->_mp_size <= 0)
+    gfc_warning ("INTEGER expression of %s clause at %L must be positive",
+                     clause, &expr->where);
+}
+
+
 /* OpenMP directive resolving routines.  */
 
 static void
@@ -800,10 +1381,17 @@  resolve_omp_clauses (gfc_code *code)
 {
   gfc_omp_clauses *omp_clauses = code->ext.omp_clauses;
   gfc_namelist *n;
+  gfc_oacc_clauses *oacc_clauses = omp_clauses;
+  gfc_exprlist *el;
   int list;
   static const char *clause_names[]
     = { "PRIVATE", "FIRSTPRIVATE", "LASTPRIVATE", "COPYPRIVATE", "SHARED",
 	"COPYIN", "REDUCTION" };
+  static const char *oacc_clause_names[]
+    = { "COPY", "COPYIN", "COPYOUT", "CREATE", "DELETE",
+        "PRESENT", "PRESENT_OR_COPY", "PRESENT_OR_COPYIN", "PRESENT_OR_COPYOUT",
+        "PRESENT_OR_CREATE", "DEVICEPTR", "USE_DEVICE", "DEVICE_RESIDENT",
+        "HOST", "DEVICE", "CACHE"};
 
   if (omp_clauses == NULL)
     return;
@@ -843,7 +1431,7 @@  resolve_omp_clauses (gfc_code *code)
 
   /* 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 (list = 0; list < OACC_LIST_NUM; list++)
     for (n = omp_clauses->lists[list]; n; n = n->next)
       {
 	n->sym->mark = 0;
@@ -1005,6 +1593,12 @@  resolve_omp_clauses (gfc_code *code)
 		  gfc_error ("Variable '%s' in %s clause is used in "
 			     "NAMELIST statement at %L",
 			     n->sym->name, name, &code->loc);
+	        if (omp_clauses->is_acc
+	            && list >= OACC_LIST_REDUCTION_FIRST
+	            && list <= OACC_LIST_REDUCTION_LAST
+	            && n->sym->as && n->sym->as->rank != 0)
+	          gfc_error ("OpenACC reduction requires SCALAR variable "
+	                     "at %L", &code->loc);
 		switch (list)
 		  {
 		  case OMP_LIST_PLUS:
@@ -1059,6 +1653,82 @@  resolve_omp_clauses (gfc_code *code)
 	    break;
 	  }
       }
+  if (!oacc_clauses->is_acc)
+    return;
+
+  /* In OpenACC, single variable may appear in several clauses,
+     such as COPYIN and COPYOUT. However, it's better to replace these clause 
+     with COPY. Hence, we use warning instead of error. */
+  for (list = OACC_LIST_FIRST; list < OACC_LIST_NUM; list++)
+    for (n = oacc_clauses->lists[list]; n; n = n->next)
+      {
+        if (n->sym->mark)
+          gfc_warning ("Symbol '%s' present on multiple clauses at %L",
+              n->sym->name, &code->loc);
+        else
+          n->sym->mark = 1;
+      }
+  if (oacc_clauses->async)
+    if (oacc_clauses->async_expr)
+      resolve_oacc_scalar_int_expr (oacc_clauses->async_expr, "ASYNC");
+  if (oacc_clauses->num_gangs_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->num_gangs_expr, "NUM_GANGS");
+  if (oacc_clauses->num_workers_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->num_workers_expr, "NUM_WORKERS");
+  if (oacc_clauses->vector_length_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->vector_length_expr, "VECTOR_LENGTH");
+  if (oacc_clauses->gang_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->gang_expr, "GANG");
+  if (oacc_clauses->worker_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->worker_expr, "WORKER");
+  if (oacc_clauses->vector_expr)
+    resolve_oacc_positive_int_expr (oacc_clauses->vector_expr, "VECTOR");
+  if (oacc_clauses->wait)
+    if (oacc_clauses->waitlist)
+      for (el = oacc_clauses->waitlist; el; el = el->next)
+        resolve_oacc_positive_int_expr (el->expr, "WAIT");
+
+  for (list = OACC_LIST_FIRST; list < OACC_LIST_NUM; list++)
+    if ((n = oacc_clauses->lists[list]) != NULL)
+      {
+        const char *name = oacc_clause_names[list - OACC_LIST_FIRST];
+
+        if (list > OACC_LIST_DATA_CLAUSE_LAST)
+          {
+            if (n->sym->attr.pointer)
+              gfc_error ("POINTER object '%s' in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+            if (n->sym->as && n->sym->as->type == AS_ASSUMED_SIZE)
+              gfc_error ("Assumed size array '%s' in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+          }
+
+        if (list == OACC_LIST_DEVICEPTR)
+          {
+            if (n->sym->attr.pointer)
+              gfc_error ("POINTER object '%s' in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+            if (n->sym->attr.allocatable)
+              gfc_error ("ALLOCATABLE object '%s' in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+            if (n->sym->attr.value)
+              gfc_error ("VALUE object '%s' in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+          }
+
+        if (list >= OACC_LIST_DATA_CLAUSE_FIRST
+            && list <= OACC_LIST_DATA_CLAUSE_LAST)
+          {
+            if (n->sym->ts.type == BT_DERIVED
+                && n->sym->attr.allocatable)
+              gfc_error ("ALLOCATABLE object '%s' of DERIVED type in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+            if (n->sym->ts.type == BT_DERIVED
+                && n->sym->attr.pointer)
+              gfc_error ("POINTER object '%s' of DERIVED type in %s clause at %L",
+                         n->sym->name, name, &code->loc);
+          }
+      }
 }
 
 
@@ -1727,6 +2397,342 @@  resolve_omp_do (gfc_code *code)
     }
 }
 
+typedef struct omp_context oacc_context;
+oacc_context *oacc_current_ctx;
+
+static bool
+oacc_is_parallel (gfc_code *code)
+{
+  return code->op == EXEC_OACC_PARALLEL || code->op == EXEC_OACC_PARALLEL_LOOP;
+}
+
+static bool
+oacc_is_kernels (gfc_code *code)
+{
+  return code->op == EXEC_OACC_KERNELS || code->op == EXEC_OACC_KERNELS_LOOP;
+}
+
+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_LOOP;
+}
+
+
+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 ("!$ACC LOOP cannot be a DO WHILE or DO without loop control "
+                     "at %L", &do_code->loc);
+          break;
+        }
+      gcc_assert (do_code->op == EXEC_DO);
+      if (do_code->ext.iterator->var->ts.type != BT_INTEGER)
+        gfc_error ("!$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 ("!$ACC LOOP %s loops don't form rectangular iteration space at %L",
+                             clause, &do_code->loc);
+                  break;
+                }
+              if (j < i)
+                break;
+              do_code2 = do_code2->block->next;
+            }
+        }
+      if (i == collapse)
+        break;
+      for (c = do_code->next; c; c = c->next)
+        if (c->op != EXEC_NOP && c->op != EXEC_CONTINUE)
+          {
+            gfc_error ("%s !$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)
+        {
+          gfc_error ("not enough DO loops for %s !$ACC LOOP at %L",
+                     clause, &code->loc);
+          break;
+        }
+      do_code = do_code->next;
+      if (do_code == NULL
+          || (do_code->op != EXEC_DO && do_code->op != EXEC_DO_WHILE))
+        {
+          gfc_error ("not enough DO loops for %s !$ACC LOOP at %L",
+                     clause, &code->loc);
+          break;
+        }
+    }
+}
+
+static void
+resolve_oacc_params_in_parallel (gfc_code *code, const char *clause)
+{
+  oacc_context *c;
+
+  if (oacc_is_parallel (code))
+    gfc_error ("LOOP %s in PARALLEL section allows no argument or static at %L",
+               clause, &code->loc);
+  for (c = oacc_current_ctx; c; c = c->previous)
+    {
+      if (oacc_is_loop (c->code))
+        break;
+      if (oacc_is_parallel (c->code))
+        gfc_error ("LOOP %s in PARALLEL section allows no argument or static at %L",
+                   clause, &code->loc);
+    }
+}
+
+
+static void
+resolve_oacc_loop_blocks (gfc_code *code)
+{
+  oacc_context *c;
+
+  if (!oacc_is_loop (code))
+    return;
+
+  if (code->op == EXEC_OACC_LOOP)
+    for (c = oacc_current_ctx; c; c = c->previous)
+      {
+        if (oacc_is_loop (c->code))
+          {
+            if (code->ext.omp_clauses->gang)
+              {
+                if (c->code->ext.omp_clauses->gang)
+                  gfc_error ("Loop parallelized across gangs is not allowed "
+                             "inside another loop parallelized across gangs at %L",
+                             &code->loc);
+                if (c->code->ext.omp_clauses->worker)
+                  gfc_error ("Loop parallelized across gangs is not allowed "
+                             "inside loop parallelized across workers at %L",
+                             &code->loc);
+                if (c->code->ext.omp_clauses->vector)
+                  gfc_error ("Loop parallelized across gangs is not allowed "
+                             "inside loop parallelized across workers at %L",
+                             &code->loc);
+              }
+            if (code->ext.omp_clauses->worker)
+              {
+                if (c->code->ext.omp_clauses->worker)
+                  gfc_error ("Loop parallelized across workers is not allowed "
+                             "inside another loop parallelized across workers at %L",
+                             &code->loc);
+                if (c->code->ext.omp_clauses->vector)
+                  gfc_error ("Loop parallelized across workers is not allowed "
+                             "inside another loop parallelized across vectors at %L",
+                             &code->loc);
+              }
+            if (code->ext.omp_clauses->vector)
+              if (c->code->ext.omp_clauses->vector)
+                gfc_error ("Loop parallelized across vectors is not allowed "
+                           "inside another loop parallelized across vectors at %L",
+                           &code->loc);
+          }
+
+        if (oacc_is_parallel (c->code) || oacc_is_kernels (c->code))
+          break;
+      }
+
+  if (code->ext.omp_clauses->seq)
+    {
+      if (code->ext.omp_clauses->independent)
+        gfc_error ("Both SEQ and INDEPENDENT are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->gang)
+        gfc_error ("Both SEQ and GANG are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->worker)
+        gfc_error ("Both SEQ and WORKER are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->vector)
+        gfc_error ("Both SEQ and VECTOR are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->par_auto)
+        gfc_error ("Both SEQ and AUTO are not allowed in %L", &code->loc);
+    }
+  if (code->ext.omp_clauses->par_auto)
+    {
+      if (code->ext.omp_clauses->gang)
+        gfc_error ("Both AUTO and GANG are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->worker)
+        gfc_error ("Both AUTO and WORKER are not allowed in %L", &code->loc);
+      if (code->ext.omp_clauses->vector)
+        gfc_error ("Both AUTO and VECTOR are not allowed in %L", &code->loc);
+    }
+  if (!code->ext.omp_clauses->tilelist)
+    {
+      if (code->ext.omp_clauses->gang)
+        {
+          if (code->ext.omp_clauses->worker)
+            gfc_error ("Both GANG and WORKER are not allowed in %L", &code->loc);
+          if (code->ext.omp_clauses->vector)
+            gfc_error ("Both GANG and VECTOR are not allowed in %L", &code->loc);
+        }
+      if (code->ext.omp_clauses->worker)
+        if (code->ext.omp_clauses->vector)
+          gfc_error ("Both WORKER and VECTOR are not allowed in %L", &code->loc);
+    }
+  else if (code->ext.omp_clauses->gang
+           && code->ext.omp_clauses->worker
+           && code->ext.omp_clauses->vector)
+    gfc_error ("All GANG, WORKER and VECTOR are not allowed in %L", &code->loc);
+
+  if (code->ext.omp_clauses->gang
+      && code->ext.omp_clauses->gang_expr
+      && !code->ext.omp_clauses->gang_static)
+    resolve_oacc_params_in_parallel (code, "GANG");
+
+  if (code->ext.omp_clauses->worker
+      && code->ext.omp_clauses->worker_expr)
+    resolve_oacc_params_in_parallel (code, "WORKER");
+
+  if (code->ext.omp_clauses->tilelist)
+    {
+      gfc_exprlist *el;
+      int num = 0;
+      for (el = code->ext.omp_clauses->tilelist; el; el = el->next)
+        {
+          num++;
+          if (el->expr == NULL)
+            continue;
+          resolve_oacc_positive_int_expr (el->expr, "TILE");
+          if (el->expr->expr_type != EXPR_CONSTANT)
+            gfc_error ("TILE requires constant expression at %L", &code->loc);
+        }
+      resolve_oacc_nested_loops (code, code->block->next, num, "tiled");
+    }
+}
+
+
+void
+gfc_resolve_oacc_blocks (gfc_code *code, gfc_namespace *ns)
+{
+  oacc_context ctx;
+
+  resolve_oacc_loop_blocks (code);
+
+  ctx.code = code;
+  ctx.previous = oacc_current_ctx;
+  oacc_current_ctx = &ctx;
+
+  gfc_resolve_blocks (code->block, ns);
+
+  oacc_current_ctx = ctx.previous;
+}
+
+
+static void
+resolve_oacc_loop(gfc_code *code)
+{
+  gfc_code *do_code;
+  int collapse;
+  int list;
+
+  if (code->ext.omp_clauses)
+    resolve_omp_clauses (code);
+
+  for (list = OACC_LIST_REDUCTION_FIRST; list <= OACC_LIST_REDUCTION_LAST; list++)
+    if (code->ext.omp_clauses->lists[list])
+      {
+        bool kernels_region = false;
+        oacc_context *c;
+
+        if (code->op == EXEC_OACC_KERNELS_LOOP)
+          kernels_region = true;
+        if (!kernels_region)
+          for (c = oacc_current_ctx; c != NULL && !kernels_region; c = c->previous)
+            if (c->code->op == EXEC_OACC_KERNELS)
+              kernels_region = true;
+
+        if (kernels_region)
+          {
+            gfc_error ("REDUCTION clause is not allowed in KERNELS region at %L",
+                &code->loc);
+            break;
+          }
+      }
+
+  do_code = code->block->next;
+  collapse = code->ext.omp_clauses->collapse;
+
+  if (collapse <= 0)
+    collapse = 1;
+  resolve_oacc_nested_loops (code, do_code, collapse, "collapsed");
+}
+
+
+static void
+resolve_oacc_cache (gfc_code *)
+{
+	//TODO: resolve subarrays
+}
+
+
+static void
+resolve_oacc_wait (gfc_code *code)
+{
+  gfc_exprlist* el;
+
+  for (el = code->ext.omp_clauses->waitlist; el; el = el->next)
+    resolve_oacc_positive_int_expr (el->expr, "WAIT");
+}
+
+
+void
+gfc_resolve_oacc_directive (gfc_code *code, gfc_namespace *ns ATTRIBUTE_UNUSED)
+{
+  switch (code->op)
+    {
+    case EXEC_OACC_PARALLEL:
+    case EXEC_OACC_KERNELS:
+    case EXEC_OACC_DATA:
+    case EXEC_OACC_HOST_DATA:
+    case EXEC_OACC_UPDATE:
+    case EXEC_OACC_ENTER_DATA:
+    case EXEC_OACC_EXIT_DATA:
+      resolve_omp_clauses (code);
+      break;
+    case EXEC_OACC_PARALLEL_LOOP:
+    case EXEC_OACC_KERNELS_LOOP:
+    case EXEC_OACC_LOOP:
+      resolve_oacc_loop (code);
+      break;
+    case EXEC_OACC_CACHE:
+      resolve_oacc_cache (code);
+      break;
+    case EXEC_OACC_WAIT:
+      resolve_oacc_wait (code);
+      break;
+    default:
+      break;
+    }
+}
+
 
 /* Resolve OpenMP directive clauses and check various requirements
    of each directive.  */
-- 
1.8.3.2