Add OpenACC 2.6 `serial' construct support

    The `serial' construct (cf. section 2.5.3 of the OpenACC 2.6 standard)
    is equivalent to a `parallel' construct with clauses `num_gangs(1)
    num_workers(1) vector_length(1)' implied.
    These clauses are therefore not supported with the `serial'
    construct. All the remaining clauses accepted with `parallel' are also
    accepted with `serial'.

    The `serial' construct is implemented like `parallel', except for
    hardcoding dimensions rather than taking them from the relevant
    clauses, in `expand_omp_target'.

    Separate codes are used to denote the `serial' construct throughout the
    middle end, even though the mapping of `serial' to an equivalent
    `parallel' construct could have been done in the individual language
    frontends. In particular, this allows to distinguish between compute
    constructs in warnings, error messages, dumps etc.

    2019-11-12  Maciej W. Rozycki  <macro@codesourcery.com>
                Tobias Burnus  <tobias@codesourcery.com>
                Frederik Harwath  <frederik@codesourcery.com>
                Thomas Schwinge  <thomas@codesourcery.com>

    gcc/
    * gimple.h (gf_mask): Add GF_OMP_TARGET_KIND_OACC_SERIAL
    enumeration constant.
    (is_gimple_omp_oacc): Handle GF_OMP_TARGET_KIND_OACC_SERIAL.
    (is_gimple_omp_offloaded): Likewise.
    * gimplify.c (omp_region_type): Add ORT_ACC_SERIAL enumeration
    constant.  Adjust the value of ORT_NONE accordingly.
    (is_gimple_stmt): Handle OACC_SERIAL.
    (oacc_default_clause): Handle ORT_ACC_SERIAL.
    (gomp_needs_data_present): Likewise.
    (gimplify_adjust_omp_clauses): Likewise.
    (gimplify_omp_workshare): Handle OACC_SERIAL.
    (gimplify_expr): Likewise.
    * omp-expand.c (expand_omp_target):
    Handle GF_OMP_TARGET_KIND_OACC_SERIAL.
    (build_omp_regions_1, omp_make_gimple_edges): Likewise.
    * omp-low.c (is_oacc_parallel): Rename function to...
    (is_oacc_parallel_or_serial): ... this.
    Handle GF_OMP_TARGET_KIND_OACC_SERIAL.
    (scan_sharing_clauses): Adjust accordingly.
    (scan_omp_for): Likewise.
    (lower_oacc_head_mark): Likewise.
    (convert_from_firstprivate_int): Likewise.
    (lower_omp_target): Likewise.
    (check_omp_nesting_restrictions): Handle
    GF_OMP_TARGET_KIND_OACC_SERIAL.
    (lower_oacc_reductions): Likewise.
    (lower_omp_target): Likewise.
    * tree.def (OACC_SERIAL): New tree code.
    * tree-pretty-print.c (dump_generic_node): Handle OACC_SERIAL.

    * doc/generic.texi (OpenACC): Document OACC_SERIAL.

    gcc/c-family/
    * c-pragma.h (pragma_kind): Add PRAGMA_OACC_SERIAL enumeration
    constant.
    * c-pragma.c (oacc_pragmas): Add "serial" entry.

    gcc/c/
    * c-parser.c (OACC_SERIAL_CLAUSE_MASK): New macro.
    (c_parser_oacc_kernels_parallel): Rename function to...
    (c_parser_oacc_compute): ... this.  Handle PRAGMA_OACC_SERIAL.
    (c_parser_omp_construct): Update accordingly.

    gcc/cp/
    * constexpr.c (potential_constant_expression_1): Handle
    OACC_SERIAL.
    * parser.c (OACC_SERIAL_CLAUSE_MASK): New macro.
    (cp_parser_oacc_kernels_parallel): Rename function to...
    (cp_parser_oacc_compute): ... this.  Handle PRAGMA_OACC_SERIAL.
    (cp_parser_omp_construct): Update accordingly.
    (cp_parser_pragma): Handle PRAGMA_OACC_SERIAL.  Fix alphabetic
    order.
    * pt.c (tsubst_expr): Handle OACC_SERIAL.

    gcc/fortran/
    * gfortran.h (gfc_statement): Add ST_OACC_SERIAL_LOOP,
    ST_OACC_END_SERIAL_LOOP, ST_OACC_SERIAL and ST_OACC_END_SERIAL
    enumeration constants.
    (gfc_exec_op): Add EXEC_OACC_SERIAL_LOOP and EXEC_OACC_SERIAL
    enumeration constants.
    * match.h (gfc_match_oacc_serial): New prototype.
    (gfc_match_oacc_serial_loop): Likewise.
    * dump-parse-tree.c (show_omp_node, show_code_node): Handle
    EXEC_OACC_SERIAL_LOOP and EXEC_OACC_SERIAL.
    * match.c (match_exit_cycle): Handle EXEC_OACC_SERIAL_LOOP.
    * openmp.c (OACC_SERIAL_CLAUSES): New macro.
    (gfc_match_oacc_serial_loop): New function.
    (gfc_match_oacc_serial): Likewise.
    (oacc_is_loop): Handle EXEC_OACC_SERIAL_LOOP.
    (resolve_omp_clauses): Handle EXEC_OACC_SERIAL.
    (oacc_code_to_statement): Handle EXEC_OACC_SERIAL and
    EXEC_OACC_SERIAL_LOOP.
    (gfc_resolve_oacc_directive): Likewise.
    * parse.c (decode_oacc_directive) <'s'>: Add case for "serial"
    and "serial loop".
    (next_statement): Handle ST_OACC_SERIAL_LOOP and ST_OACC_SERIAL.
    (gfc_ascii_statement): Likewise.  Handle ST_OACC_END_SERIAL_LOOP
    and ST_OACC_END_SERIAL.
    (parse_oacc_structured_block): Handle ST_OACC_SERIAL.
    (parse_oacc_loop): Handle ST_OACC_SERIAL_LOOP and
    ST_OACC_END_SERIAL_LOOP.
    (parse_executable): Handle ST_OACC_SERIAL_LOOP and
    ST_OACC_SERIAL.
    (is_oacc): Handle EXEC_OACC_SERIAL_LOOP and EXEC_OACC_SERIAL.
    * resolve.c (gfc_resolve_blocks, gfc_resolve_code): Likewise.
    * st.c (gfc_free_statement): Likewise.
    * trans-openmp.c (gfc_trans_oacc_construct): Handle
    EXEC_OACC_SERIAL.
    (gfc_trans_oacc_combined_directive): Handle
    EXEC_OACC_SERIAL_LOOP.
    (gfc_trans_oacc_directive): Handle EXEC_OACC_SERIAL_LOOP and
    EXEC_OACC_SERIAL.
    * trans.c (trans_code): Likewise.

    gcc/testsuite/
    * c-c++-common/goacc/parallel-dims.c: New test.
    * gfortran.dg/goacc/parallel-dims.f90: New test.

    libgomp/
    * testsuite/libgomp.oacc-c-c++-common/parallel-dims.c: New test.
    * testsuite/libgomp.oacc-fortran/parallel-dims-aux.c: New test.
    * testsuite/libgomp.oacc-fortran/parallel-dims.f89: New test.
    * testsuite/libgomp.oacc-fortran/parallel-dims-2.f90: New test.

Reviewed-by: Thomas Schwinge <thomas@codesourcery.com>


Co-Authored-By: Frederik Harwath <frederik@codesourcery.com>
Co-Authored-By: Thomas Schwinge <thomas@codesourcery.com>
Co-Authored-By: Tobias Burnus <tobias@codesourcery.com>

From-SVN: r278082

1 files changed, 36 insertions, 7 deletions

diff --git a/gcc/omp-expand.c b/gcc/omp-expand.c
index eadff6e..6f94501 100644
--- a/gcc/omp-expand.c
+++ b/gcc/omp-expand.c
@@ -7901,12 +7901,14 @@ expand_omp_target (struct omp_region *region)
   gimple *stmt;
   edge e;
   bool offloaded, data_region;
+  int target_kind;
 
   entry_stmt = as_a <gomp_target *> (last_stmt (region->entry));
+  target_kind = gimple_omp_target_kind (entry_stmt);
   new_bb = region->entry;
 
   offloaded = is_gimple_omp_offloaded (entry_stmt);
-  switch (gimple_omp_target_kind (entry_stmt))
+  switch (target_kind)
     {
     case GF_OMP_TARGET_KIND_REGION:
     case GF_OMP_TARGET_KIND_UPDATE:
@@ -7914,6 +7916,7 @@ expand_omp_target (struct omp_region *region)
     case GF_OMP_TARGET_KIND_EXIT_DATA:
     case GF_OMP_TARGET_KIND_OACC_PARALLEL:
     case GF_OMP_TARGET_KIND_OACC_KERNELS:
+    case GF_OMP_TARGET_KIND_OACC_SERIAL:
     case GF_OMP_TARGET_KIND_OACC_UPDATE:
     case GF_OMP_TARGET_KIND_OACC_ENTER_EXIT_DATA:
     case GF_OMP_TARGET_KIND_OACC_DECLARE:
@@ -7944,16 +7947,28 @@ expand_omp_target (struct omp_region *region)
   entry_bb = region->entry;
   exit_bb = region->exit;
 
-  if (gimple_omp_target_kind (entry_stmt) == GF_OMP_TARGET_KIND_OACC_KERNELS)
+  switch (target_kind)
     {
+    case GF_OMP_TARGET_KIND_OACC_KERNELS:
       mark_loops_in_oacc_kernels_region (region->entry, region->exit);
 
-      /* Further down, both OpenACC kernels and OpenACC parallel constructs
-	 will be mappted to BUILT_IN_GOACC_PARALLEL, and to distinguish the
-	 two, there is an "oacc kernels" attribute set for OpenACC kernels.  */
+      /* Further down, all OpenACC compute constructs will be mapped to
+	 BUILT_IN_GOACC_PARALLEL, and to distinguish between them, there
+	 is an "oacc kernels" attribute set for OpenACC kernels.  */
       DECL_ATTRIBUTES (child_fn)
 	= tree_cons (get_identifier ("oacc kernels"),
 		     NULL_TREE, DECL_ATTRIBUTES (child_fn));
+      break;
+    case GF_OMP_TARGET_KIND_OACC_SERIAL:
+      /* Further down, all OpenACC compute constructs will be mapped to
+	 BUILT_IN_GOACC_PARALLEL, and to distinguish between them, there
+	 is an "oacc serial" attribute set for OpenACC serial.  */
+      DECL_ATTRIBUTES (child_fn)
+	= tree_cons (get_identifier ("oacc serial"),
+		     NULL_TREE, DECL_ATTRIBUTES (child_fn));
+      break;
+    default:
+      break;
     }
 
   if (offloaded)
@@ -8156,8 +8171,9 @@ expand_omp_target (struct omp_region *region)
       start_ix = BUILT_IN_GOMP_TARGET_ENTER_EXIT_DATA;
       flags_i |= GOMP_TARGET_FLAG_EXIT_DATA;
       break;
-    case GF_OMP_TARGET_KIND_OACC_KERNELS:
     case GF_OMP_TARGET_KIND_OACC_PARALLEL:
+    case GF_OMP_TARGET_KIND_OACC_KERNELS:
+    case GF_OMP_TARGET_KIND_OACC_SERIAL:
       start_ix = BUILT_IN_GOACC_PARALLEL;
       break;
     case GF_OMP_TARGET_KIND_OACC_DATA:
@@ -8352,7 +8368,18 @@ expand_omp_target (struct omp_region *region)
 	args.quick_push (get_target_arguments (&gsi, entry_stmt));
       break;
     case BUILT_IN_GOACC_PARALLEL:
-      oacc_set_fn_attrib (child_fn, clauses, &args);
+      if (lookup_attribute ("oacc serial", DECL_ATTRIBUTES (child_fn)) != NULL)
+	{
+	  tree dims = NULL_TREE;
+	  unsigned int ix;
+
+	  /* For serial constructs we set all dimensions to 1.  */
+	  for (ix = GOMP_DIM_MAX; ix--;)
+	    dims = tree_cons (NULL_TREE, integer_one_node, dims);
+	  oacc_replace_fn_attrib (child_fn, dims);
+	}
+      else
+	oacc_set_fn_attrib (child_fn, clauses, &args);
       tagging = true;
       /* FALLTHRU */
     case BUILT_IN_GOACC_ENTER_EXIT_DATA:
@@ -8913,6 +8940,7 @@ build_omp_regions_1 (basic_block bb, struct omp_region *parent,
 		case GF_OMP_TARGET_KIND_DATA:
 		case GF_OMP_TARGET_KIND_OACC_PARALLEL:
 		case GF_OMP_TARGET_KIND_OACC_KERNELS:
+		case GF_OMP_TARGET_KIND_OACC_SERIAL:
 		case GF_OMP_TARGET_KIND_OACC_DATA:
 		case GF_OMP_TARGET_KIND_OACC_HOST_DATA:
 		  break;
@@ -9167,6 +9195,7 @@ omp_make_gimple_edges (basic_block bb, struct omp_region **region,
 	case GF_OMP_TARGET_KIND_DATA:
 	case GF_OMP_TARGET_KIND_OACC_PARALLEL:
 	case GF_OMP_TARGET_KIND_OACC_KERNELS:
+	case GF_OMP_TARGET_KIND_OACC_SERIAL:
 	case GF_OMP_TARGET_KIND_OACC_DATA:
 	case GF_OMP_TARGET_KIND_OACC_HOST_DATA:
 	  break;