From: Sandra Loosemore <san...@codesourcery.com>

This patch detects loops in kernels regions that are candidates for
parallelization, and adds "#pragma acc loop auto" annotations to them.
This annotation is controlled by the -fopenacc-kernels-annotate-loops
option, which is enabled by default.  -Wopenacc-kernels-annotate-loops
can be used to produce diagnostics about loops that cannot be annotated.

gcc/c-family/
        * c-common.h (c_oacc_annotate_loops_in_kernels_regions): Declare.
        * c-omp.c: Include tree-iterator.h
        (enum annotation_state): New.
        (struct annotation_info): New.
        (do_not_annotate_loop): New.
        (do_not_annotate_loop_nest): New.
        (annotation_error): New.
        (c_finish_omp_for_internal): Split from c_finish_omp_for.  Use
        annotation_error function.  Code refactoring to avoid destructive
        changes that cannot be undone in case of error.
        (is_local_var): New.
        (lang_specific_unwrap_initializer): New.
        (annotate_for_loop): New.
        (check_and_annotate_for_loop): New.
        (annotate_loops_in_kernels_regions): New.
        (c_oacc_annotate_loops_in_kernels_regions): New.
        * c.opt (Wopenacc-kernels-annotate-loops): New.
        (fopenacc-kernels-annotate-loops): New.

gcc/c/
        * c-decl.c (c_unwrap_for_init): New.
        (finish_function): Call c_oacc_annotate_loops_in_kernels_regions.

gcc/cp/
        * decl.c (cp_unwrap_for_init): New.
        (finish_function): Call c_oacc_annotate_loops_in_kernels_regions.

gcc/
        * doc/invoke.texi (Option Summary): Add entries for
        -Wopenacc-kernels-annotate-loops and
        -fno-openacc-kernels-annotate-loops.
        (Warning Options): Document -Wopenacc-kernels-annotate-loops.
        (Optimization Options): Document -fno-openacc-kernels-annotate-loops.

gcc/testsuite/
        * c-c++-common/goacc/classify-kernels-unparallelized.c: Add
        -fno-openacc-kernels-annotate-loops option.
        * c-c++-common/goacc/classify-kernels.c: Likewise.
        * c-c++-common/goacc/kernels-counter-var-redundant-load.c: Likewise.
        * c-c++-common/goacc/kernels-counter-vars-function-scope.c: Likewise.
        * c-c++-common/goacc/kernels-double-reduction.c: Likewise.
        * c-c++-common/goacc/kernels-double-reduction-n.c: Likewise.
        * c-c++-common/goacc/kernels-loop-2.c: Likewise.
        * c-c++-common/goacc/kernels-loop-3.c: Likewise.
        * c-c++-common/goacc/kernels-loop-data-2.c: Likewise.
        * c-c++-common/goacc/kernels-loop-data-enter-exit-2.c: Likewise.
        * c-c++-common/goacc/kernels-loop-data-enter-exit.c: Likewise.
        * c-c++-common/goacc/kernels-loop-data-update.c: Likewise.
        * c-c++-common/goacc/kernels-loop-data.c: Likewise.
        * c-c++-common/goacc/kernels-loop-g.c: Likewise.
        * c-c++-common/goacc/kernels-loop-mod-not-zero.c: Likewise.
        * c-c++-common/goacc/kernels-loop-n.c: Likewise.
        * c-c++-common/goacc/kernels-loop-nest.c: Likewise.
        * c-c++-common/goacc/kernels-loop.c: Likewise.
        * c-c++-common/goacc/kernels-one-counter-var.c: Likewise.
        * c-c++-common/goacc/kernels-parallel-loop-data-enter-exit.c:
        Likewise.
        * c-c++-common/goacc/kernels-reduction.c: Likewise.
        * c-c++-common/goacc/kernels-loop-annotation-1.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-2.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-3.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-4.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-5.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-6.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-7.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-8.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-9.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-10.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-11.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-12.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-13.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-14.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-15.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-16.c: New.
        * c-c++-common/goacc/kernels-loop-annotation-17.c: New.
---
 gcc/c-family/c-common.h                       |   1 +
 gcc/c-family/c-omp.c                          | 799 ++++++++++++++++--
 gcc/c-family/c.opt                            |   8 +
 gcc/c/c-decl.c                                |  28 +
 gcc/cp/decl.c                                 |  44 +
 gcc/doc/invoke.texi                           |  32 +-
 .../goacc/classify-kernels-unparallelized.c   |   1 +
 .../c-c++-common/goacc/classify-kernels.c     |   3 +-
 .../kernels-counter-var-redundant-load.c      |   1 +
 .../kernels-counter-vars-function-scope.c     |   1 +
 .../goacc/kernels-double-reduction-n.c        |   1 +
 .../goacc/kernels-double-reduction.c          |   1 +
 .../c-c++-common/goacc/kernels-loop-2.c       |   1 +
 .../c-c++-common/goacc/kernels-loop-3.c       |   1 +
 .../goacc/kernels-loop-annotation-1.c         |  26 +
 .../goacc/kernels-loop-annotation-10.c        |  32 +
 .../goacc/kernels-loop-annotation-11.c        |  27 +
 .../goacc/kernels-loop-annotation-12.c        |  28 +
 .../goacc/kernels-loop-annotation-13.c        |  27 +
 .../goacc/kernels-loop-annotation-14.c        |  22 +
 .../goacc/kernels-loop-annotation-15.c        |  22 +
 .../goacc/kernels-loop-annotation-16.c        |  26 +
 .../goacc/kernels-loop-annotation-17.c        |  26 +
 .../goacc/kernels-loop-annotation-2.c         |  21 +
 .../goacc/kernels-loop-annotation-3.c         |  24 +
 .../goacc/kernels-loop-annotation-4.c         |  34 +
 .../goacc/kernels-loop-annotation-5.c         |  27 +
 .../goacc/kernels-loop-annotation-6.c         |  27 +
 .../goacc/kernels-loop-annotation-7.c         |  26 +
 .../goacc/kernels-loop-annotation-8.c         |  27 +
 .../goacc/kernels-loop-annotation-9.c         |  26 +
 .../c-c++-common/goacc/kernels-loop-data-2.c  |   1 +
 .../goacc/kernels-loop-data-enter-exit-2.c    |   1 +
 .../goacc/kernels-loop-data-enter-exit.c      |   1 +
 .../goacc/kernels-loop-data-update.c          |   1 +
 .../c-c++-common/goacc/kernels-loop-data.c    |   1 +
 .../c-c++-common/goacc/kernels-loop-g.c       |   1 +
 .../goacc/kernels-loop-mod-not-zero.c         |   1 +
 .../c-c++-common/goacc/kernels-loop-n.c       |   1 +
 .../c-c++-common/goacc/kernels-loop-nest.c    |   1 +
 .../c-c++-common/goacc/kernels-loop.c         |   1 +
 .../goacc/kernels-one-counter-var.c           |   1 +
 .../kernels-parallel-loop-data-enter-exit.c   |   1 +
 .../c-c++-common/goacc/kernels-reduction.c    |   1 +
 44 files changed, 1322 insertions(+), 61 deletions(-)
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-1.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-10.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-11.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-12.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-13.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-14.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-15.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-16.c
 create mode 100644 
gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-17.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-2.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-3.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-4.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-5.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-6.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-7.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-8.c
 create mode 100644 gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-9.c

diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index f60714e34160..f8b414401a5d 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1247,6 +1247,7 @@ extern enum omp_clause_default_kind 
c_omp_predetermined_sharing (tree);
 extern enum omp_clause_defaultmap_kind c_omp_predetermined_mapping (tree);
 extern tree c_omp_check_context_selector (location_t, tree);
 extern void c_omp_mark_declare_variant (location_t, tree, tree);
+extern void c_oacc_annotate_loops_in_kernels_regions (tree, tree (*) (tree));
 extern const char *c_omp_map_clause_name (tree, bool);
 extern void c_omp_adjust_map_clauses (tree, bool);

diff --git a/gcc/c-family/c-omp.c b/gcc/c-family/c-omp.c
index fad060670b65..fad50da8fbc4 100644
--- a/gcc/c-family/c-omp.c
+++ b/gcc/c-family/c-omp.c
@@ -37,7 +37,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "langhooks.h"
 #include "bitmap.h"
 #include "gimple-fold.h"
-
+#include "tree-iterator.h"

 /* Complete a #pragma oacc wait construct.  LOC is the location of
    the #pragma.  */
@@ -918,6 +918,110 @@ c_omp_for_incr_canonicalize_ptr (location_t loc, tree 
decl, tree incr)
   return incr;
 }

+/* State of annotation traversal for FOR loops in kernels regions,
+   used to control processing and diagnostic messages that are deferred until
+   the entire loop has been scanned.  */
+enum annotation_state {
+  as_outer,
+  as_in_kernels_region,
+  as_in_kernels_loop,
+  /* The remaining state values represent conversion failures caught
+     while in as_in_kernels_loop state.  To test whether the traversal is
+     in the body of a kernels loop, use (state >= as_in_kernels_loop).  */
+  as_invalid_variable_type,
+  as_missing_initializer,
+  as_invalid_initializer,
+  as_missing_predicate,
+  as_invalid_predicate,
+  as_missing_increment,
+  as_invalid_increment,
+  as_explicit_annotation,
+  as_invalid_control_flow,
+  as_invalid_break,
+  as_invalid_return,
+  as_invalid_call,
+  as_invalid_modification
+};
+
+/* Structure used to hold state for automatic annotation of FOR loops
+   in kernels regions.  LOOP is the nearest enclosing loop, or
+   NULL_TREE if outside of a loop context.  VARS is a tree_list
+   containing the variables controlling LOOP's termination (the
+   induction variable and a possible limit variable).  STATE keeps
+   track of whether loop satisfies all criteria making it legal to
+   parallelize.  Otherwise, REASON is a statement that blocks
+   automatic parallelization, such as an unstructured jump or an
+   assignment to a variable in VARS, used for printing diagnostics.
+
+   These structures are chained through NEXT, which points to the
+   next-closest enclosing loop's or the kernels region's annotation info, if
+   any.  */
+
+struct annotation_info
+{
+  tree loop;
+  tree vars;
+  bool break_ok;
+  enum annotation_state state;
+  tree reason;
+  struct annotation_info *next;
+};
+
+/* Mark the current loop's INFO as not OK to annotate, recording STATE
+   and REASON for producing diagnostics later.  */
+
+static void
+do_not_annotate_loop (struct annotation_info *info,
+                     enum annotation_state state, tree reason)
+{
+  if (info->state == as_in_kernels_loop)
+    {
+      info->state = state;
+      info->reason = reason;
+    }
+}
+
+/* Mark the current loop identified by INFO and all of its ancestors (i.e.,
+   enclosing loops) as not OK to annotate.  Arguments are the same as
+   for do_not_annotate_loop.  */
+
+static void
+do_not_annotate_loop_nest (struct annotation_info *info,
+                          enum annotation_state state, tree reason)
+{
+  while (info != NULL)
+    {
+      do_not_annotate_loop (info, state, reason);
+      info = info->next;
+    }
+}
+
+/* If INFO is non-null, call do_not_annotate_loop with STATE and REASON
+   to record info for diagnosing an error later.  Otherwise emit an error now
+   at ELOCUS with message MSG and the optional arguments.  */
+
+static void annotation_error (struct annotation_info *,
+                             enum annotation_state, tree, location_t,
+                             const char *, ...) ATTRIBUTE_GCC_DIAG(5,6);
+static
+void annotation_error (struct annotation_info *info,
+                             enum annotation_state state,
+                             tree reason,
+                             location_t elocus,
+                             const char *msg, ...)
+{
+  if (info)
+    do_not_annotate_loop (info, state, reason);
+  else
+    {
+      auto_diagnostic_group d;
+      va_list ap;
+      va_start (ap, msg);
+      emit_diagnostic_valist (DK_ERROR, elocus, -1, msg, &ap);
+      va_end (ap);
+    }
+}
+
 /* Validate and generate OMP_FOR.
    DECLV is a vector of iteration variables, for each collapsed loop.

@@ -927,12 +1031,19 @@ c_omp_for_incr_canonicalize_ptr (location_t loc, tree 
decl, tree incr)
    INITV, CONDV and INCRV are vectors containing initialization
    expressions, controlling predicates and increment expressions.
    BODY is the body of the loop and PRE_BODY statements that go before
-   the loop.  */
+   the loop.  FINAL_P is true if not inside a C++ template.

-tree
-c_finish_omp_for (location_t locus, enum tree_code code, tree declv,
-                 tree orig_declv, tree initv, tree condv, tree incrv,
-                 tree body, tree pre_body, bool final_p)
+   INFO is null if called to parse an explicitly-annotated OMP for
+   loop, otherwise it holds state information for automatically
+   annotating a regular FOR loop in a kernels region.  In the former case,
+   malformed loops are hard errors; otherwise we just record the annotation
+   failure in INFO.  */
+
+static tree
+c_finish_omp_for_internal (location_t locus, enum tree_code code, tree declv,
+                          tree orig_declv, tree initv, tree condv, tree incrv,
+                          tree body, tree pre_body, bool final_p,
+                          struct annotation_info *info)
 {
   location_t elocus;
   bool fail = false;
@@ -956,12 +1067,14 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
       if (!INTEGRAL_TYPE_P (TREE_TYPE (decl))
          && TREE_CODE (TREE_TYPE (decl)) != POINTER_TYPE)
        {
-         error_at (elocus, "invalid type for iteration variable %qE", decl);
+         annotation_error (info, as_invalid_variable_type, decl, elocus,
+                           "invalid type for iteration variable %qE", decl);
          fail = true;
        }
       else if (TYPE_ATOMIC (TREE_TYPE (decl)))
        {
-         error_at (elocus, "%<_Atomic%> iteration variable %qE", decl);
+         annotation_error (info, as_invalid_variable_type, decl, elocus,
+                           "%<_Atomic%> iteration variable %qE", decl);
          fail = true;
          /* _Atomic iterator confuses stuff too much, so we risk ICE
             trying to diagnose it further.  */
@@ -977,7 +1090,8 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
          init = DECL_INITIAL (decl);
          if (init == NULL)
            {
-             error_at (elocus, "%qE is not initialized", decl);
+             annotation_error (info, as_missing_initializer, decl, elocus,
+                               "%qE is not initialized", decl);
              init = integer_zero_node;
              fail = true;
            }
@@ -998,7 +1112,8 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,

       if (cond == NULL_TREE)
        {
-         error_at (elocus, "missing controlling predicate");
+         annotation_error (info, as_missing_predicate, NULL_TREE, elocus,
+                           "missing controlling predicate");
          fail = true;
        }
       else
@@ -1014,12 +1129,14 @@ c_finish_omp_for (location_t locus, enum tree_code 
code, tree declv,
          if (EXPR_HAS_LOCATION (cond))
            elocus = EXPR_LOCATION (cond);

-         if (TREE_CODE (cond) == LT_EXPR
-             || TREE_CODE (cond) == LE_EXPR
-             || TREE_CODE (cond) == GT_EXPR
-             || TREE_CODE (cond) == GE_EXPR
-             || TREE_CODE (cond) == NE_EXPR
-             || TREE_CODE (cond) == EQ_EXPR)
+         enum tree_code condcode = TREE_CODE (cond);
+
+         if (condcode == LT_EXPR
+             || condcode == LE_EXPR
+             || condcode == GT_EXPR
+             || condcode == GE_EXPR
+             || condcode == NE_EXPR
+             || condcode == EQ_EXPR)
            {
              tree op0 = TREE_OPERAND (cond, 0);
              tree op1 = TREE_OPERAND (cond, 1);
@@ -1039,79 +1156,88 @@ c_finish_omp_for (location_t locus, enum tree_code 
code, tree declv,
              if (TREE_CODE (op0) == NOP_EXPR
                  && decl == TREE_OPERAND (op0, 0))
                {
-                 TREE_OPERAND (cond, 0) = TREE_OPERAND (op0, 0);
-                 TREE_OPERAND (cond, 1)
-                   = fold_build1_loc (elocus, NOP_EXPR, TREE_TYPE (decl),
-                                  TREE_OPERAND (cond, 1));
+                 op0 = TREE_OPERAND (op0, 0);
+                 op1 = fold_build1_loc (elocus, NOP_EXPR, TREE_TYPE (decl),
+                                        op1);
                }
              else if (TREE_CODE (op1) == NOP_EXPR
                       && decl == TREE_OPERAND (op1, 0))
                {
-                 TREE_OPERAND (cond, 1) = TREE_OPERAND (op1, 0);
-                 TREE_OPERAND (cond, 0)
-                   = fold_build1_loc (elocus, NOP_EXPR, TREE_TYPE (decl),
-                                  TREE_OPERAND (cond, 0));
+                 op1 = TREE_OPERAND (op1, 0);
+                 op0 = fold_build1_loc (elocus, NOP_EXPR, TREE_TYPE (decl),
+                                        op0);
                }

-             if (decl == TREE_OPERAND (cond, 0))
+             if (decl == op0)
                cond_ok = true;
-             else if (decl == TREE_OPERAND (cond, 1))
+             else if (decl == op1)
                {
-                 TREE_SET_CODE (cond,
-                                swap_tree_comparison (TREE_CODE (cond)));
-                 TREE_OPERAND (cond, 1) = TREE_OPERAND (cond, 0);
-                 TREE_OPERAND (cond, 0) = decl;
+                 condcode = swap_tree_comparison (condcode);
+                 op1 = op0;
+                 op0 = decl;
                  cond_ok = true;
                }

-             if (TREE_CODE (cond) == NE_EXPR
-                 || TREE_CODE (cond) == EQ_EXPR)
+             if (condcode == NE_EXPR || condcode == EQ_EXPR)
                {
                  if (!INTEGRAL_TYPE_P (TREE_TYPE (decl)))
                    {
-                     if (code == OACC_LOOP || TREE_CODE (cond) == EQ_EXPR)
+                     if (code == OACC_LOOP || condcode == EQ_EXPR)
                        cond_ok = false;
                    }
-                 else if (operand_equal_p (TREE_OPERAND (cond, 1),
+                 else if (operand_equal_p (op1,
                                            TYPE_MIN_VALUE (TREE_TYPE (decl)),
                                            0))
-                   TREE_SET_CODE (cond, TREE_CODE (cond) == NE_EXPR
-                                        ? GT_EXPR : LE_EXPR);
-                 else if (operand_equal_p (TREE_OPERAND (cond, 1),
+                   condcode = (condcode == NE_EXPR ? GT_EXPR : LE_EXPR);
+                 else if (operand_equal_p (op1,
                                            TYPE_MAX_VALUE (TREE_TYPE (decl)),
                                            0))
-                   TREE_SET_CODE (cond, TREE_CODE (cond) == NE_EXPR
-                                        ? LT_EXPR : GE_EXPR);
-                 else if (code == OACC_LOOP || TREE_CODE (cond) == EQ_EXPR)
+                   condcode = (condcode == NE_EXPR ? LT_EXPR : GE_EXPR);
+                 else if (code == OACC_LOOP || condcode == EQ_EXPR)
                    cond_ok = false;
                }

-             if (cond_ok && TREE_VEC_ELT (condv, i) != cond)
+             if (cond_ok)
                {
-                 tree ce = NULL_TREE, *pce = &ce;
-                 tree type = TREE_TYPE (TREE_OPERAND (cond, 1));
-                 for (tree c = TREE_VEC_ELT (condv, i); c != cond;
-                      c = TREE_OPERAND (c, 1))
+                 /* We postponed destructive changes to canonicalize
+                    cond until we're sure it is OK.  In the !error_p
+                    case where we are trying to transform a regular FOR_STMT
+                    to OMP_FOR, we don't want to destroy the original
+                    condition if we aren't going to be able to do the
+                    transformation anyway.  */
+                 TREE_SET_CODE (cond, condcode);
+                 TREE_OPERAND (cond, 0) = op0;
+                 TREE_OPERAND (cond, 1) = op1;
+
+                 if (TREE_VEC_ELT (condv, i) != cond)
                    {
-                     *pce = build2 (COMPOUND_EXPR, type, TREE_OPERAND (c, 0),
-                                    TREE_OPERAND (cond, 1));
-                     pce = &TREE_OPERAND (*pce, 1);
+                     tree ce = NULL_TREE, *pce = &ce;
+                     tree type = TREE_TYPE (op1);
+                     for (tree c = TREE_VEC_ELT (condv, i); c != cond;
+                          c = TREE_OPERAND (c, 1))
+                       {
+                         *pce = build2 (COMPOUND_EXPR, type,
+                                        TREE_OPERAND (c, 0), op1);
+                         pce = &TREE_OPERAND (*pce, 1);
+                       }
+                     op1 = ce;
+                     TREE_VEC_ELT (condv, i) = cond;
                    }
-                 TREE_OPERAND (cond, 1) = ce;
-                 TREE_VEC_ELT (condv, i) = cond;
                }
            }

          if (!cond_ok)
            {
-             error_at (elocus, "invalid controlling predicate");
+             annotation_error (info, as_invalid_predicate, cond, elocus,
+                               "invalid controlling predicate");
              fail = true;
            }
        }

       if (incr == NULL_TREE)
        {
-         error_at (elocus, "missing increment expression");
+         annotation_error (info, as_missing_increment, NULL_TREE, elocus,
+                           "missing increment expression");
          fail = true;
        }
       else
@@ -1210,9 +1336,11 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
                              if (i == NULL_TREE
                                  || !operand_equal_p (unit, i, 0))
                                {
-                                 error_at (elocus,
-                                           "increment is not constant 1 or "
-                                           "-1 for %<!=%> condition");
+                                 annotation_error (info,
+                                                   as_invalid_increment,
+                                                   incr, elocus,
+                                                   "increment is not constant 
1 or "
+                                                   "-1 for %<!=%> condition");
                                  fail = true;
                                }
                            }
@@ -1228,9 +1356,10 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
                    {
                      if (!integer_onep (i) && !integer_minus_onep (i))
                        {
-                         error_at (elocus,
-                                   "increment is not constant 1 or -1 for"
-                                   " %<!=%> condition");
+                         annotation_error (info, as_invalid_increment,
+                                           incr, elocus,
+                                           "increment is not constant 1 or -1 
for"
+                                           " %<!=%> condition");
                          fail = true;
                        }
                    }
@@ -1242,7 +1371,8 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
            }
          if (!incr_ok)
            {
-             error_at (elocus, "invalid increment expression");
+             annotation_error (info, as_invalid_increment, incr,
+                               elocus, "invalid increment expression");
              fail = true;
            }
        }
@@ -1270,6 +1400,20 @@ c_finish_omp_for (location_t locus, enum tree_code code, 
tree declv,
     }
 }

+/* External entry point to c_finish_omp_for_internal, called from the
+   parsers.  See above for description of the arguments.  */
+
+tree
+c_finish_omp_for (location_t locus, enum tree_code code, tree declv,
+                 tree orig_declv, tree initv, tree condv, tree incrv,
+                 tree body, tree pre_body, bool final_p)
+{
+  return c_finish_omp_for_internal (locus, code, declv,
+                                   orig_declv, initv, condv, incrv,
+                                   body, pre_body, final_p, NULL);
+}
+
+
 /* Type for passing data in between c_omp_check_loop_iv and
    c_omp_check_loop_iv_r.  */

@@ -3000,6 +3144,543 @@ c_omp_map_clause_name (tree clause, bool oacc)
   return omp_clause_code_name[OMP_CLAUSE_CODE (clause)];
 }

+/* The following functions implement automatic recognition and annotation of
+   for loops in OpenACC kernels regions.  Inside a kernels region, a nest of
+   for loops that does not contain any annotated OpenACC loops, nor break
+   or goto statements or assignments to the variables controlling loop
+   termination, is converted to an OMP_FOR node with an "acc loop auto"
+   annotation on each loop.  This feature is controlled by
+   flag_openacc_kernels_annotate_loops.  */
+
+/* Check whether DECL is the declaration of a local variable (or function
+   parameter) of integral type that does not have its address taken.  */
+
+static bool
+is_local_var (tree decl)
+{
+  return ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
+         && DECL_CONTEXT (decl) != NULL
+         && TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL
+         && INTEGRAL_TYPE_P (TREE_TYPE (decl))
+         && !TREE_ADDRESSABLE (decl));
+}
+
+/* The initializer for a FOR_STMT is sometimes wrapped in various other
+   language-specific tree structures.  We need a hook to unwrap them.
+   This function takes a tree argument and should return either a
+   MODIFY_EXPR, VAR_DECL, or NULL_TREE.  */
+
+static tree (*lang_specific_unwrap_initializer) (tree);
+
+/* Try to annotate the given NODE, which must be a FOR_STMT, with a
+   "#pragma acc loop auto" annotation.  In practice, this means
+   building an OMP_FOR node for it.  PREV_STMT is the statement
+   immediately before the loop, which may be used as the loop's
+   initialization statement.  Annotating the loop may fail, in which
+   case INFO is used to record the cause of the failure and the
+   original loop remains unchanged.  This function returns the
+   transformed loop if the transformation succeeded, the original node
+   otherwise.  */
+
+static tree
+annotate_for_loop (tree node, tree_stmt_iterator *prev_tsi,
+                  struct annotation_info *info)
+{
+  gcc_checking_assert (TREE_CODE (node) == FOR_STMT);
+
+  location_t loc = EXPR_LOCATION (node);
+  tree cond = FOR_COND (node);
+  gcc_assert (cond);
+  tree decl = TREE_OPERAND (cond, 0);
+  gcc_assert (decl && TREE_CODE (decl) == VAR_DECL);
+  tree init = FOR_INIT_STMT (node);
+  tree prev_stmt = NULL_TREE;
+  bool unlink_prev = false;
+  bool fix_decl = false;
+
+
+  /* Both the C and C++ front ends normally put the initializer in the
+     statement list just before the FOR_STMT instead of in FOR_INIT_STMT.
+     If FOR_INIT_STMT happens to exist but isn't a MODIFY_EXPR, bail out
+     because the code below won't handle it.  */
+  if (init != NULL_TREE && TREE_CODE (init) != MODIFY_EXPR)
+    {
+      do_not_annotate_loop (info, as_invalid_initializer, NULL_TREE);
+      return node;
+    }
+
+  /* Examine the statement before the loop to see if it is a
+     valid initializer.  It must be either a MODIFY_EXPR or VAR_DECL,
+     possibly wrapped in language-specific structure.  */
+  if (init == NULL_TREE && prev_tsi != NULL)
+    {
+      prev_stmt = tsi_stmt (*prev_tsi);
+
+      /* Call the language-specific hook to unwrap prev_stmt.  */
+      if (prev_stmt)
+       prev_stmt = (*lang_specific_unwrap_initializer) (prev_stmt);
+
+      /* See if we have a valid MODIFY_EXPR.  */
+      if (prev_stmt
+         && TREE_CODE (prev_stmt) == MODIFY_EXPR
+         && TREE_OPERAND (prev_stmt, 0) == decl
+         && !TREE_SIDE_EFFECTS (TREE_OPERAND (prev_stmt, 1)))
+       {
+         init = prev_stmt;
+         unlink_prev = true;
+       }
+      else if (prev_stmt == decl
+              && !TREE_SIDE_EFFECTS (DECL_INITIAL (decl)))
+       {
+         /* If the preceding statement is the declaration of the loop
+            variable with its initialization, build an assignment
+            expression for the loop's initializer.  */
+         init = build2 (MODIFY_EXPR, TREE_TYPE (decl), decl,
+                        DECL_INITIAL (decl));
+         /* We need to remove the initializer from the decl if we
+            end up using the init we just built instead.  */
+         fix_decl = true;
+       }
+    }
+
+  if (init == NULL_TREE)
+    /* There is nothing we can do to find the correct init statement for
+       this loop, but c_finish_omp_for insists on having one and would fail
+       otherwise.  In that case, we would just return node.  Do that
+       directly, here.  */
+    {
+      do_not_annotate_loop (info, as_missing_initializer, NULL_TREE);
+      return node;
+    }
+
+  tree incr = FOR_EXPR (node);
+
+  /* The C++ frontend can wrap the increment two levels deep inside a
+     cleanup expression, but c_finish_omp_for does not care about that.  */
+  if (incr != NULL_TREE && TREE_CODE (incr) == CLEANUP_POINT_EXPR)
+    incr = TREE_OPERAND (TREE_OPERAND (incr, 0), 0);
+  tree body = FOR_BODY (node);
+
+  tree declv = make_tree_vec (1);
+  tree initv = make_tree_vec (1);
+  tree condv = make_tree_vec (1);
+  tree incrv = make_tree_vec (1);
+  TREE_VEC_ELT (declv, 0) = decl;
+  TREE_VEC_ELT (initv, 0) = init;
+  TREE_VEC_ELT (condv, 0) = cond;
+  TREE_VEC_ELT (incrv, 0) = incr;
+
+  /* Do the actual transformation.  This can still fail because
+     c_finish_omp_for has some stricter checks than we have performed up to
+     this point.  */
+  tree omp_for = c_finish_omp_for_internal (loc, OACC_LOOP, declv, NULL_TREE,
+                                           initv, condv, incrv, body,
+                                           NULL_TREE, false, info);
+  if (omp_for != NULL_TREE)
+    {
+      if (unlink_prev)
+       /* We don't need the previous statement that we consumed as an
+          initializer in the new OMP_FOR any more.  */
+       tsi_delink (prev_tsi);
+
+      if (fix_decl)
+       /* We no longer need the initializer expression on the decl of
+          the loop variable and don't want to duplicate it.  The
+          kernels conversion pass would interpret it as a stray
+          assignment in a gang-single region.  */
+       DECL_INITIAL (prev_stmt) = NULL_TREE;
+
+      /* Add an auto clause, then return the new loop.  */
+      tree auto_clause = build_omp_clause (loc, OMP_CLAUSE_AUTO);
+      OMP_CLAUSE_CHAIN (auto_clause) = OMP_FOR_CLAUSES (omp_for);
+      OMP_FOR_CLAUSES (omp_for) = auto_clause;
+      return omp_for;
+    }
+
+  return node;
+}
+
+/* Forward declaration.  */
+static tree annotate_loops_in_kernels_regions (tree *, int *, void *);
+
+/* Given a FOR_STMT NODE that is a candidate for parallelization, check its
+   body for validity, then try to annotate it with
+   "#pragma oacc loop auto", possibly modifying the current node in place.
+   The INFO argument contains the traversal state at the point the loop
+   appears.  */
+
+static void
+check_and_annotate_for_loop (tree *nodeptr, tree_stmt_iterator *prev_tsi,
+                            struct annotation_info *info)
+{
+  tree node = *nodeptr;
+  gcc_assert (TREE_CODE (node) == FOR_STMT);
+
+  /* This structure describes the current loop statement.  */
+  struct annotation_info loop_info
+    = { node, NULL_TREE, false, as_in_kernels_loop, NULL_TREE, info };
+  tree cond = FOR_COND (node);
+
+  /* If we are in the body of an explicitly-annotated loop, do not add
+     annotations to this loop or any other nested loops.  */
+  if (info->state == as_explicit_annotation)
+    do_not_annotate_loop (&loop_info, as_explicit_annotation, info->reason);
+
+  /* We need to find the controlling variable for the loop in order
+     to detect whether it is modified in the body of the loop.
+     That is why we are doing some checks on the loop condition
+     that duplicate what c_finish_omp_for is doing.  */
+
+  /* The loop condition must be a comparison.  */
+  else if (cond == NULL_TREE)
+    do_not_annotate_loop (&loop_info, as_missing_predicate, NULL_TREE);
+  else if (TREE_CODE_CLASS (TREE_CODE (cond)) != tcc_comparison)
+    do_not_annotate_loop (&loop_info, as_invalid_predicate, cond);
+  else
+    {
+      /* The condition's LHS must be a local variable that does not
+        have its address taken.  Its RHS must also be such a local
+        variable or a constant.  */
+      tree induction_var = TREE_OPERAND (cond, 0);
+      tree limit_var = TREE_OPERAND (cond, 1);
+      if (!is_local_var (induction_var)
+         || (!is_local_var (limit_var)
+             && (TREE_CODE_CLASS (TREE_CODE (limit_var))
+                 != tcc_constant)))
+       do_not_annotate_loop (&loop_info, as_invalid_predicate, cond);
+      else
+       {
+         /* These variables must not be assigned to in the loop.  */
+         loop_info.vars = tree_cons (NULL_TREE, induction_var,
+                                     loop_info.vars);
+         if (TREE_CODE_CLASS (TREE_CODE (limit_var)) != tcc_constant)
+           loop_info.vars = tree_cons (NULL_TREE, limit_var, loop_info.vars);
+       }
+    }
+
+  /* Walk the body.  This will process any nested loops, so we have to do it
+     even if we have already rejected this loop as a candidate for
+     annotation.  */
+  walk_tree (&FOR_BODY (node), annotate_loops_in_kernels_regions,
+            (void *) &loop_info, NULL);
+
+  if (loop_info.state == as_in_kernels_loop)
+    {
+      /* If the traversal of the loop and all nested loops didn't hit
+        any problems, attempt the actual transformation.  If it
+        succeeds, replace this node with the annotated loop.  */
+      tree result = annotate_for_loop (node, prev_tsi, &loop_info);
+      if (result != node)
+       {
+         /* Success!  */
+         *nodeptr = result;
+         return;
+       }
+    }
+
+  /* If we got here, we have a FOR_STMT we could not convert to an
+     OMP loop.  */
+
+  if (loop_info.state == as_invalid_return)
+    /* This is diagnosed elsewhere as a hard error, so no warning is
+       needed here.  */
+    return;
+
+  /* Issue warnings about other problems.  */
+  auto_diagnostic_group d;
+  if (warning_at (EXPR_LOCATION (node),
+                 OPT_Wopenacc_kernels_annotate_loops,
+                 "loop cannot be annotated for OpenACC parallelization"))
+    {
+      location_t locus;
+      if (loop_info.reason && EXPR_HAS_LOCATION (loop_info.reason))
+       locus = EXPR_LOCATION (loop_info.reason);
+      else
+       locus = EXPR_LOCATION (node);
+      switch (loop_info.state)
+       {
+       case as_invalid_variable_type:
+         inform (locus, "invalid type for iteration variable %qE",
+                 loop_info.reason);
+         break;
+       case as_missing_initializer:
+         inform (locus, "missing iteration variable initializer");
+         break;
+       case as_invalid_initializer:
+         inform (locus, "unrecognized initializer");
+         break;
+       case as_missing_predicate:
+         inform (locus, "missing controlling predicate");
+         break;
+       case as_invalid_predicate:
+         inform (locus, "invalid controlling predicate");
+         break;
+       case as_missing_increment:
+         inform (locus, "missing increment expression");
+         break;
+       case as_invalid_increment:
+         inform (locus, "invalid increment expression");
+         break;
+       case as_explicit_annotation:
+         inform (locus, "explicit OpenACC annotation in loop nest");
+         break;
+       case as_invalid_control_flow:
+         inform (locus, "loop contains unstructured control flow");
+         break;
+       case as_invalid_break:
+         inform (locus, "loop contains %<break%> statement");
+         break;
+       case as_invalid_call:
+         inform (locus, "loop contains call to non-oacc function");
+         break;
+       case as_invalid_modification:
+         inform (locus, "invalid modification of controlling variable");
+         break;
+       default:
+         gcc_unreachable ();
+       }
+    }
+}
+
+/* Traversal function for walk_tree.  Visit the tree, finding OpenACC
+   kernels regions.  DATA is NULL if we are outside of a kernels region,
+   otherwise it is a pointer to the enclosing kernels region's
+   annotation_info struct.  If the traversal encounters a for loop inside a
+   kernels region that is a candidate for parallelization, annotate it
+   with OpenACC loop directives.  */
+
+static tree
+annotate_loops_in_kernels_regions (tree *nodeptr, int *walk_subtrees,
+                                  void *data)
+{
+  tree node = *nodeptr;
+  struct annotation_info *info = (struct annotation_info *) data;
+  gcc_assert (info);
+
+  switch (TREE_CODE (node))
+    {
+    case OACC_KERNELS:
+      /* Recursively process the body of the kernels region in a new info
+        scope.  */
+      if (info->state == as_outer)
+       {
+         struct annotation_info nested_info
+           = { NULL_TREE, NULL_TREE, true,
+               as_in_kernels_region, NULL_TREE, info };
+         walk_tree (&OMP_BODY (node), annotate_loops_in_kernels_regions,
+                    (void *) &nested_info, NULL);
+         *walk_subtrees = 0;
+       }
+      break;
+
+    case OACC_LOOP:
+      /* Do not try to add automatic OpenACC annotations inside manually
+        annotated loops.  Presumably, the user avoided doing it on
+        purpose; for example, all available levels of parallelism may
+        have been used up.  */
+      {
+       struct annotation_info nested_info
+         = { NULL_TREE, NULL_TREE, false, as_explicit_annotation,
+             node, info };
+       if (info->state >= as_in_kernels_region)
+         do_not_annotate_loop_nest (info, as_explicit_annotation,
+                                    node);
+       walk_tree (&OMP_BODY (node), annotate_loops_in_kernels_regions,
+                  (void *) &nested_info, NULL);
+       *walk_subtrees = 0;
+      }
+      break;
+
+    case FOR_STMT:
+      /* Try to annotate the loop if we are in a kernels region.
+        This will do a recursive traversal of the loop body in a new
+        info scope.  */
+      if (info->state >= as_in_kernels_region)
+       {
+         check_and_annotate_for_loop (nodeptr, NULL, info);
+         *walk_subtrees = 0;
+       }
+      break;
+
+    case LABEL_EXPR:
+      /* Possibly unstructured control flow.  Unless we perform further
+        analyses, we must assume that such control flow may enter the
+        current loop.  In this case, we must not parallelize the loop.  */
+      if (info->state >= as_in_kernels_loop
+         && TREE_USED (LABEL_EXPR_LABEL (node)))
+       do_not_annotate_loop_nest (info, as_invalid_control_flow, node);
+      break;
+
+    case GOTO_EXPR:
+      /* Possibly unstructured control flow.  Unless we perform further
+        analyses, we must assume that such control flow may leave the
+        current loop.  In this case, we must not parallelize the loop.  */
+      if (info->state >= as_in_kernels_loop)
+       do_not_annotate_loop_nest (info, as_invalid_control_flow, node);
+      break;
+
+    case BREAK_STMT:
+      /* A break statement.  Whether or not this is valid depends on the
+        enclosing context.  */
+      if (info->state >= as_in_kernels_loop && !info->break_ok)
+       do_not_annotate_loop (info, as_invalid_break, node);
+      break;
+
+    case RETURN_EXPR:
+      /* A return leaves the entire loop nest.  */
+      if (info->state >= as_in_kernels_loop)
+       do_not_annotate_loop_nest (info, as_invalid_return, node);
+      break;
+
+    case CALL_EXPR:
+      /* Direct function calls to functions marked as OpenACC routines are
+        allowed.  Reject indirect calls or calls to non-routines.  */
+      if (info->state >= as_in_kernels_loop)
+       {
+         tree fn = CALL_EXPR_FN (node), fn_decl = NULL_TREE;
+         if (fn != NULL_TREE && TREE_CODE (fn) == FUNCTION_DECL)
+           fn_decl = fn;
+         else if (fn != NULL_TREE && TREE_CODE (fn) == ADDR_EXPR)
+           {
+             tree fn_op = TREE_OPERAND (fn, 0);
+             if (fn_op != NULL_TREE && TREE_CODE (fn_op) == FUNCTION_DECL)
+               fn_decl = fn_op;
+           }
+         if (fn_decl == NULL_TREE)
+           do_not_annotate_loop_nest (info, as_invalid_call, node);
+         else if (!lookup_attribute ("oacc function",
+                                     DECL_ATTRIBUTES (fn_decl)))
+           do_not_annotate_loop_nest (info, as_invalid_call, node);
+       }
+      break;
+
+    case MODIFY_EXPR:
+      /* See if this assignment's LHS is one of the variables that must
+        not be modified in the loop body because they control termination
+        of the loop (or an enclosing loop in the nest).  */
+      if (info->state >= as_in_kernels_loop)
+       {
+         tree lhs = TREE_OPERAND (node, 0);
+         if (!is_local_var (lhs))
+           /* Early exit: This cannot be a variable we care about.  */
+           break;
+         /* Walk up the loop stack.  Invalidate the ones controlled by this
+            variable.  There may be several, if this variable is the common
+            iteration limit for several nested loops.  */
+         for (struct annotation_info *outer_loop = info; outer_loop != NULL;
+              outer_loop = outer_loop->next)
+           for (tree t = outer_loop->vars; t != NULL_TREE; t = TREE_CHAIN (t))
+             if (TREE_VALUE (t) == lhs)
+               {
+                 do_not_annotate_loop (outer_loop,
+                                       as_invalid_modification,
+                                       node);
+                 break;
+               }
+       }
+      break;
+
+    case SWITCH_STMT:
+      /* Needs special handling to allow break in the body.  */
+      if (info->state >= as_in_kernels_loop)
+       {
+         bool save_break_ok = info->break_ok;
+
+         walk_tree (&SWITCH_STMT_COND (node),
+                    annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = true;
+         walk_tree (&SWITCH_STMT_BODY (node),
+                    annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = save_break_ok;
+         *walk_subtrees = 0;
+       }
+      break;
+
+    case WHILE_STMT:
+      /* Needs special handling to allow break in the body.  */
+      if (info->state >= as_in_kernels_loop)
+       {
+         bool save_break_ok = info->break_ok;
+
+         walk_tree (&WHILE_COND (node), annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = true;
+         walk_tree (&WHILE_BODY (node), annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = save_break_ok;
+         *walk_subtrees = 0;
+       }
+      break;
+
+    case DO_STMT:
+      /* Needs special handling to allow break in the body.  */
+      if (info->state >= as_in_kernels_loop)
+       {
+         bool save_break_ok = info->break_ok;
+
+         walk_tree (&DO_COND (node), annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = true;
+         walk_tree (&DO_BODY (node), annotate_loops_in_kernels_regions,
+                    (void *) info, NULL);
+         info->break_ok = save_break_ok;
+         *walk_subtrees = 0;
+       }
+      break;
+
+    case STATEMENT_LIST:
+      /* We iterate over these explicitly so that we can track the previous
+        statement in the chain.  It may be the initializer for a following
+        FOR_STMT node.  */
+      if (info->state >= as_in_kernels_region)
+       {
+         tree_stmt_iterator i = tsi_start (node);
+         tree_stmt_iterator prev, *prev_tsi = NULL;
+         while (!tsi_end_p (i))
+           {
+             tree *stmtptr = tsi_stmt_ptr (i);
+             if (TREE_CODE (*stmtptr) == FOR_STMT)
+               {
+                 check_and_annotate_for_loop (stmtptr, prev_tsi, info);
+                 *walk_subtrees = 0;
+               }
+             else
+               walk_tree (stmtptr, annotate_loops_in_kernels_regions,
+                          (void *) info, NULL);
+             prev = i;
+             prev_tsi = &prev;
+             tsi_next (&i);
+           }
+         *walk_subtrees = 0;
+       }
+      break;
+
+    default:
+      break;
+    }
+
+  return NULL_TREE;
+}
+
+/* Find for loops in OpenACC kernels regions that do not have OpenACC
+   annotations but look like they might benefit from automatic
+   parallelization.  Convert them from FOR_STMT to OMP_FOR nodes and
+   add the equivalent of "#pragma acc loop auto" annotations for them.
+   Assumes flag_openacc_kernels_annotate_loops is set.  */
+
+void
+c_oacc_annotate_loops_in_kernels_regions (tree decl,
+                                         tree (*unwrap_fn) (tree))
+{
+  struct annotation_info info
+    = { NULL_TREE, NULL_TREE, true, as_outer, NULL_TREE, NULL };
+  lang_specific_unwrap_initializer = unwrap_fn;
+  walk_tree (&DECL_SAVED_TREE (decl), annotate_loops_in_kernels_regions,
+            (void *) &info, NULL);
+}
+
 /* Used to merge map clause information in c_omp_adjust_map_clauses.  */
 struct map_clause
 {
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 06457ac739e4..a0f43d6d325f 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1074,6 +1074,10 @@ Wopenacc-parallelism
 C C++ Var(warn_openacc_parallelism) Warning
 Warn about potentially suboptimal choices related to OpenACC parallelism.

+Wopenacc-kernels-annotate-loops
+C ObjC C++ ObjC++ Warning Var(warn_openacc_kernels_annotate_loops) Init(0)
+Warn about loops in OpenACC kernels regions that cannot be parallelized.
+
 Wopenmp-simd
 C C++ Var(warn_openmp_simd) Warning LangEnabledBy(C C++,Wall)
 Warn if a simd directive is overridden by the vectorizer cost model.
@@ -1910,6 +1914,10 @@ fopenacc-dim=
 C ObjC C++ ObjC++ LTO Joined Var(flag_openacc_dims)
 Specify default OpenACC compute dimensions.

+fopenacc-kernels-annotate-loops
+C ObjC C++ ObjC++ LTO Optimization Var(flag_openacc_kernels_annotate_loops) 
Init(1)
+Automatically parallelize unannotated loops in OpenACC kernels regions.
+
 fopenmp
 C ObjC C++ ObjC++ LTO Var(flag_openmp)
 Enable OpenMP (implies -frecursive in Fortran).
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 186fa1692c16..467b3425b9a4 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -10230,6 +10230,29 @@ temp_pop_parm_decls (void)
   pop_scope ();
 }

+/* Function passed to c_oacc_annotate_loop_in_kernels_regions to do
+   language-specific unwrapping of an initializer expression.  */
+static tree
+c_unwrap_for_init (tree x)
+{
+  if (!x)
+    return NULL_TREE;
+
+  while (true)
+    switch (TREE_CODE (x))
+      {
+      case MODIFY_EXPR:
+      case VAR_DECL:
+       return x;
+
+      case DECL_EXPR:
+       x = TREE_OPERAND (x, 0);
+       break;
+
+      default:
+       return NULL_TREE;
+      }
+}

 /* Finish up a function declaration and compile that function
    all the way to assembler language output.  Then free the storage
@@ -10332,6 +10355,11 @@ finish_function (location_t end_loc)
   if (warn_unused_parameter)
     do_warn_unused_parameter (fndecl);

+  /* If requested, automatically annotate suitable loops in OpenACC kernels
+     regions with OpenACC loop annotations to allow auto-parallelization.  */
+  if (flag_openacc && flag_openacc_kernels_annotate_loops)
+    c_oacc_annotate_loops_in_kernels_regions (fndecl, c_unwrap_for_init);
+
   /* Store the end of the function, so that we get good line number
      info for the epilogue.  */
   cfun->function_end_locus = end_loc;
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 7c2a134e4061..17f14d1f6742 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -17528,6 +17528,45 @@ emit_coro_helper (tree helper)
   expand_or_defer_fn (helper);
 }

+
+/* Function passed to c_oacc_annotate_loop_in_kernels_regions to do
+   language-specific unwrapping of an initializer expression.  */
+static tree
+cp_unwrap_for_init (tree x)
+{
+  if (!x)
+    return NULL_TREE;
+
+  while (true)
+    switch (TREE_CODE (x))
+      {
+      case MODIFY_EXPR:
+      case VAR_DECL:
+       return x;
+
+      case CLEANUP_POINT_EXPR:
+       x = TREE_OPERAND (x, 0);
+       break;
+
+      case EXPR_STMT:
+       x = TREE_OPERAND (x, 0);
+       break;
+
+      case DECL_EXPR:
+       x = TREE_OPERAND (x, 0);
+       break;
+
+      case CONVERT_EXPR:
+       if (TREE_TYPE (x) != void_type_node)
+         return NULL_TREE;
+       x = TREE_OPERAND (x, 0);
+       break;
+
+      default:
+       return NULL_TREE;
+      }
+}
+
 /* Finish up a function declaration and compile that function
    all the way to assembler language output.  The free the storage
    for the function definition. INLINE_P is TRUE if we just
@@ -17832,6 +17871,11 @@ finish_function (bool inline_p)
       && !DECL_CLONED_FUNCTION_P (fndecl))
     do_warn_unused_parameter (fndecl);

+  /* If requested, automatically annotate suitable loops in OpenACC kernels
+     regions with OpenACC loop annotations to allow auto-parallelization.  */
+  if (flag_openacc && flag_openacc_kernels_annotate_loops)
+    c_oacc_annotate_loops_in_kernels_regions (fndecl, cp_unwrap_for_init);
+
   /* Genericize before inlining.  */
   if (!processing_template_decl
       && !DECL_IMMEDIATE_FUNCTION_P (fndecl)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 9fb74d349203..e0f09610408c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -371,6 +371,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wnull-dereference  -Wno-odr  @gol
 -Wopenacc-parallelism  @gol
 -Wopenmp-simd  @gol
+-Wopenacc-kernels-annotate-loops  -Wopenmp-simd @gol
 -Wno-overflow  -Woverlength-strings  -Wno-override-init-side-effects @gol
 -Wpacked  -Wno-packed-bitfield-compat  -Wpacked-not-aligned  -Wpadded @gol
 -Wparentheses  -Wno-pedantic-ms-format @gol
@@ -533,7 +534,8 @@ Objective-C and Objective-C++ Dialects}.
 -fmerge-constants  -fmodulo-sched  -fmodulo-sched-allow-regmoves @gol
 -fmove-loop-invariants  -fmove-loop-stores  -fno-branch-count-reg @gol
 -fno-defer-pop  -fno-fp-int-builtin-inexact  -fno-function-cse @gol
--fno-guess-branch-probability  -fno-inline  -fno-math-errno  -fno-peephole @gol
+-fno-guess-branch-probability  -fno-inline  -fno-math-errno @gol
+-fno-openacc-kernels-annotate-loops  -fno-peephole @gol
 -fno-peephole2  -fno-printf-return-value  -fno-sched-interblock @gol
 -fno-sched-spec  -fno-signed-zeros @gol
 -fno-toplevel-reorder  -fno-trapping-math  -fno-zero-initialized-in-bss @gol
@@ -8957,6 +8959,13 @@ Enabled by default.
 @cindex OpenACC accelerator programming
 Warn about potentially suboptimal choices related to OpenACC parallelism.

+@item -Wopenacc-kernels-annotate-loops
+@opindex Wopenacc-kernels-annotate-loops
+@opindex Wno-Wopenacc-kernels-annotate-loops
+Warn about @code{for} (C/C++) or @code{DO} (Fortran) loops in OpenACC
+kernels regions that cannot be automatically annotated for
+parallelization with @option{-fopenacc-kernels-annotate-loops}.
+
 @item -Wopenmp-simd
 @opindex Wopenmp-simd
 @opindex Wno-openmp-simd
@@ -14835,6 +14844,27 @@ SIMD iterations.

 @end table

+@item -fno-openacc-kernels-annotate-loops
+@opindex fno-openacc-kernels-annotate-loops
+@opindex fopenacc-kernels-annotate-loops
+@cindex kernels regions, OpenACC
+Disable automatic parallelization of unannotated loops in OpenACC
+kernels regions.  The default is to attempt to add implicit
+@code{acc loop auto} annotations to loops in kernels regions if
+@option{-fopenacc} is enabled.
+
+Note that you can use @option{-Wopenacc-kernels-annotate-loops} to
+diagnose @code{for} loops that cannot be automatically annotated
+(@pxref{Warning Options}).  Reasons why automatic loop annotations
+cannot be applied include premature exits, calls to functions without
+an @code{openacc routine} annotation, or unstructured control flow in
+the loop body.  In C and C++, the loop variable initialization, end
+test, and increment expressions must additionally conform to
+restrictions similar to those for explicitly-annotated loops, and the
+loop variable must not be otherwise modified in the body of the loop.
+An explicit @code{acc loop} annotation disables automatic annotations
+on any nested or containing loops.
+
 @end table

 @node Instrumentation Options
diff --git a/gcc/testsuite/c-c++-common/goacc/classify-kernels-unparallelized.c 
b/gcc/testsuite/c-c++-common/goacc/classify-kernels-unparallelized.c
index 1d12658790d1..e391184f403d 100644
--- a/gcc/testsuite/c-c++-common/goacc/classify-kernels-unparallelized.c
+++ b/gcc/testsuite/c-c++-common/goacc/classify-kernels-unparallelized.c
@@ -2,6 +2,7 @@
    OpenACC kernels.  */

 /* { dg-additional-options "-O2" }
+   { dg-additional-options "-fno-openacc-kernels-annotate-loops" }
    { dg-additional-options "-fopt-info-optimized-omp" }
    { dg-additional-options "-fdump-tree-ompexp" }
    { dg-additional-options "-fdump-tree-parloops1-all" }
diff --git a/gcc/testsuite/c-c++-common/goacc/classify-kernels.c 
b/gcc/testsuite/c-c++-common/goacc/classify-kernels.c
index bdf7b4a06410..779e2b0a24db 100644
--- a/gcc/testsuite/c-c++-common/goacc/classify-kernels.c
+++ b/gcc/testsuite/c-c++-common/goacc/classify-kernels.c
@@ -1,7 +1,8 @@
 /* Check offloaded function's attributes and classification for OpenACC
-   kernels.  */
+   'kernels' (parloops version).  */

 /* { dg-additional-options "-O2" }
+   { dg-additional-options "-fno-openacc-kernels-annotate-loops" }
    { dg-additional-options "-fopt-info-optimized-omp" }
    { dg-additional-options "-fdump-tree-ompexp" }
    { dg-additional-options "-fdump-tree-parloops1-all" }
diff --git 
a/gcc/testsuite/c-c++-common/goacc/kernels-counter-var-redundant-load.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-counter-var-redundant-load.c
index 030425475495..c37152c74041 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-counter-var-redundant-load.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-counter-var-redundant-load.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-dom3" } */

 #include <stdlib.h>
diff --git 
a/gcc/testsuite/c-c++-common/goacc/kernels-counter-vars-function-scope.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-counter-vars-function-scope.c
index c475333f1aef..b1f43029af7c 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-counter-vars-function-scope.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-counter-vars-function-scope.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction-n.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction-n.c
index 8f7f415b58d8..e87aab3295c7 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction-n.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction-n.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fopt-info-optimized-omp" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction.c
index c11d36fb4373..2323857fb4ad 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-double-reduction.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fopt-info-optimized-omp" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-2.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-2.c
index acef6a1a1793..adca30bf2cd7 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-2.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-2.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-3.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-3.c
index 75e2bb78cea4..5f16085ff386 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-3.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-3.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-1.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-1.c
new file mode 100644
index 000000000000..c7b5ac882195
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-1.c
@@ -0,0 +1,26 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that all loops in the nest are annotated.  */
+
+void f (float a[16][16], float b[16][16], float c[16][16])
+{
+  int i, j, k;
+
+#pragma acc kernels copyin(a[0:16][0:16], b[0:16][0:16]) copyout(c[0:16][0:16])
+  {
+    for (i = 0; i < 16; i++) {
+      for (j = 0; j < 16; j++) {
+       float t = 0;
+       for (k = 0; k < 16; k++)
+         t += a[i][k] * b[k][j];
+       c[i][j] = t;
+      }
+    }
+  }
+
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 3 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-10.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-10.c
new file mode 100644
index 000000000000..58b41d20e232
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-10.c
@@ -0,0 +1,32 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a random goto in the body can't be annotated.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)    /* { dg-warning "loop cannot be annotated" } */
+      {
+       if (a[i] < 0)
+         {
+           t = 0;
+           goto bad;
+         }
+       t += a[i] * b[i];
+      }
+  bad:
+    ;
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-11.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-11.c
new file mode 100644
index 000000000000..e9d2ef48611a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-11.c
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a random label in the body triggers a warning.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i = n - 1;
+
+#pragma acc kernels
+  {
+    goto spaghetti;
+    for (i = 0; i < n; i++)    /* { dg-warning "loop cannot be annotated" } */
+      {
+      spaghetti:
+       t += a[i] * b[i];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-12.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-12.c
new file mode 100644
index 000000000000..ba408bc3634d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-12.c
@@ -0,0 +1,28 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that in a situation with nested loops, a problem that prevents
+   annotation of the inner loop only still allows the outer loop to be
+   annotated.  */
+
+float f (float *a, float *b, int n)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+    for (int i = 0; i < n; i++)
+      for (int j = 0; j <= i; j++)  /* { dg-warning "loop cannot be annotated" 
} */
+       {
+         if (a[i] < 0 || b[j] < 0)
+           j = i;
+         else
+           t += a[i] * b[j];
+       }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-13.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-13.c
new file mode 100644
index 000000000000..64433e816ed4
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-13.c
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that in a situation with nested loops, a problem that prevents
+   annotation of the outer loop only still allows the inner loop to be
+   annotated.  */
+
+float f (float *a, float *b, int n)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+    for (int i = 0; i < n; i++)          /* { dg-warning "loop cannot be 
annotated" } */
+      {
+       if (a[i] < 0)
+         n = i;
+       for (int j = 0; j <= i; j++)
+         t += a[i] * b[j];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-14.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-14.c
new file mode 100644
index 000000000000..379e6baf97c3
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-14.c
@@ -0,0 +1,22 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that an explicit annotation on an outer loop suppresses annotation
+   of inner loops, and produces a diagnostic.  */
+
+void f (float *a, float *b)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+#pragma acc loop seq
+    for (int l = 0; l < 20; l++)
+      for (int m = 0; m < 20; m++)     /* { dg-warning "loop cannot be 
annotated" } */
+        b[m] = a[m];
+  }
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-15.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-15.c
new file mode 100644
index 000000000000..9a2a7cabde5d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-15.c
@@ -0,0 +1,22 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that an explicit annotation on an inner loop suppresses annotation
+   of outer loops, and produces a diagnostic.  */
+
+void f (float *a, float *b)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+    for (int l = 0; l < 20; l++)       /* { dg-warning "loop cannot be 
annotated" } */
+#pragma acc loop seq
+      for (int m = 0; m < 20; m++)
+        b[m] = a[m];
+  }
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-16.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-16.c
new file mode 100644
index 000000000000..075f897fad4a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-16.c
@@ -0,0 +1,26 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a modification of the loop variable in the
+   body cannot be annotated.  */
+
+float f (float *a, float *b, int n)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+    for (int i = 0; i < n; i++)        /* { dg-warning "loop cannot be 
annotated" } */
+      {
+       if (a[i] < 0 || b[i] < 0)
+         i = n;
+       else
+         t += a[i] * b[i];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-17.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-17.c
new file mode 100644
index 000000000000..507678965b4d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-17.c
@@ -0,0 +1,26 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a modification of the loop iteration count
+   variable in the body cannot be annotated.  */
+
+float f (float *a, float *b, int n)
+{
+  float t = 0;
+
+#pragma acc kernels
+  {
+    for (int i = 0; i < n; i++)        /* { dg-warning "loop cannot be 
annotated" } */
+      {
+       if (a[i] < 0 || b[i] < 0)
+         n = i;
+       else
+         t += a[i] * b[i];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-2.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-2.c
new file mode 100644
index 000000000000..9e0a946828ff
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-2.c
@@ -0,0 +1,21 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a variable bound can be annotated.  */
+
+float f (float *a, float *b, int n)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      t += a[i] * b[i];
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-3.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-3.c
new file mode 100644
index 000000000000..f60070e27961
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-3.c
@@ -0,0 +1,24 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a conditional in the body can be annotated.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      if (a[i] > 0 && b[i] > 0)
+       t += a[i] * b[i];
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-4.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-4.c
new file mode 100644
index 000000000000..949871cc42ec
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-4.c
@@ -0,0 +1,34 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a switch and break in the body can be annotated.  */
+
+#define n 16
+
+float f (float *a, float *b, int state)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      switch (state)
+       {
+       case 0:
+       default:
+         t += a[i] * b[i];
+         break;
+
+       case 1:
+         if (a[i] > 0 && b[i] > 0)
+           t += a[i] * b[i];
+         break;
+       }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-5.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-5.c
new file mode 100644
index 000000000000..03dfe8fbcd40
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-5.c
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a continue statement in the body can be annotated.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      {
+       if (a[i] < 0 || b[i] < 0)
+         continue;
+       t += a[i] * b[i];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-6.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-6.c
new file mode 100644
index 000000000000..ede6b3c8cd67
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-6.c
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a break statement in the body cannot be annotated.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)    /* { dg-warning "loop cannot be annotated" } */
+      {
+       if (a[i] < 0 || b[i] < 0)
+         break;
+       t += a[i] * b[i];
+      }
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-7.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-7.c
new file mode 100644
index 000000000000..20ee29989665
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-7.c
@@ -0,0 +1,26 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with a random function call in the body cannot be
+   annotated.  */
+
+extern float g (float);
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)    /* { dg-warning "loop cannot be annotated" } */
+      t += g (a[i] * b[i]);
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 0 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-8.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-8.c
new file mode 100644
index 000000000000..796f048d67ca
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-8.c
@@ -0,0 +1,27 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a loop with an openacc function call in the body can be
+   annotated.  */
+
+#pragma acc routine worker
+extern float g (float);
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      t += g (a[i] * b[i]);
+  }
+  return t;
+}
+
+/* { dg-final { scan-tree-dump-times "acc loop auto" 1 "original" } } */
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-9.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-9.c
new file mode 100644
index 000000000000..048f1b09a84d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-annotation-9.c
@@ -0,0 +1,26 @@
+/* { dg-additional-options "-fopenacc -fopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-Wopenacc-kernels-annotate-loops" } */
+/* { dg-additional-options "-fdump-tree-original" } */
+/* { dg-do compile } */
+
+/* Test that a kernels loop with a return in the body triggers a hard
+   error.  */
+
+#define n 16
+
+float f (float *a, float *b)
+{
+  float t = 0;
+  int i;
+
+#pragma acc kernels
+  {
+    for (i = 0; i < n; i++)
+      {
+       if (a[i] < 0 || b[i] < 0)
+         return 0.0;   /* { dg-error "invalid branch" } */
+       t += a[i] * b[i];
+      }
+  }
+  return t;
+}
diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-2.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-2.c
index 71800217991a..9a97de6f6e13 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-2.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-2.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit-2.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit-2.c
index 0c9f83312408..31e8378e3d74 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit-2.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit-2.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit.c
index 0bd21b68d317..ad591551b979 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-enter-exit.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-update.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-update.c
index dd5a84146a8e..4acffef41ba1 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-update.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data-update.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data.c
index a658182de904..327aa0570c9c 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-data.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-data.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c
index 73b469d70610..26c65fe742aa 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c
@@ -1,5 +1,6 @@
 /* { dg-additional-options "-O2" } */
 /* { dg-additional-options "-g" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-mod-not-zero.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-mod-not-zero.c
index 55926230d578..8955cf29224b 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-mod-not-zero.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-mod-not-zero.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-n.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-n.c
index e86be1b1cdc0..d88a61dbab51 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-n.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-n.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop-nest.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop-nest.c
index 2b0e186ae297..5943d56a5bbe 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop-nest.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop-nest.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-loop.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-loop.c
index 9619d53b43d7..ad525cdbe141 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-loop.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-loop.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-one-counter-var.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-one-counter-var.c
index 69539b24a78d..f799baffd8df 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-one-counter-var.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-one-counter-var.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git 
a/gcc/testsuite/c-c++-common/goacc/kernels-parallel-loop-data-enter-exit.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-parallel-loop-data-enter-exit.c
index 81b0fee5a44c..b8093b54dec8 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-parallel-loop-data-enter-exit.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-parallel-loop-data-enter-exit.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-reduction.c 
b/gcc/testsuite/c-c++-common/goacc/kernels-reduction.c
index 5921b88920fd..105cbcf3ba2e 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-reduction.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-reduction.c
@@ -1,4 +1,5 @@
 /* { dg-additional-options "-O2" } */
+/* { dg-additional-options "-fno-openacc-kernels-annotate-loops" } */
 /* { dg-additional-options "-fdump-tree-parloops1-all" } */
 /* { dg-additional-options "-fdump-tree-optimized" } */

--
2.33.0

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