gcc/omp-general.c

   1 /* General types and functions that are uselful for processing of OpenMP,
   2    OpenACC and similar directivers at various stages of compilation.
   3
   4    Copyright (C) 2005-2019 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 /* Find an OMP clause of type KIND within CLAUSES.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "backend.h"
  28 #include "target.h"
  29 #include "tree.h"
  30 #include "gimple.h"
  31 #include "ssa.h"
  32 #include "diagnostic-core.h"
  33 #include "fold-const.h"
  34 #include "langhooks.h"
  35 #include "omp-general.h"
  36 #include "stringpool.h"
  37 #include "attribs.h"
  38
  39 enum omp_requires omp_requires_mask;
  40
  41 tree
  42 omp_find_clause (tree clauses, enum omp_clause_code kind)
  43 {
  44   for (; clauses ; clauses = OMP_CLAUSE_CHAIN (clauses))
  45     if (OMP_CLAUSE_CODE (clauses) == kind)
  46       return clauses;
  47
  48   return NULL_TREE;
  49 }
  50
  51 /* Return true if DECL is a reference type.  */
  52
  53 bool
  54 omp_is_reference (tree decl)
  55 {
  56   return lang_hooks.decls.omp_privatize_by_reference (decl);
  57 }
  58
  59 /* Adjust *COND_CODE and *N2 so that the former is either LT_EXPR or
  60    GT_EXPR.  */
  61
  62 void
  63 omp_adjust_for_condition (location_t loc, enum tree_code *cond_code, tree *n2)
  64 {
  65   switch (*cond_code)
  66     {
  67     case LT_EXPR:
  68     case GT_EXPR:
  69     case NE_EXPR:
  70       break;
  71     case LE_EXPR:
  72       if (POINTER_TYPE_P (TREE_TYPE (*n2)))
  73         *n2 = fold_build_pointer_plus_hwi_loc (loc, *n2, 1);
  74       else
  75         *n2 = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (*n2), *n2,
  76                                build_int_cst (TREE_TYPE (*n2), 1));
  77       *cond_code = LT_EXPR;
  78       break;
  79     case GE_EXPR:
  80       if (POINTER_TYPE_P (TREE_TYPE (*n2)))
  81         *n2 = fold_build_pointer_plus_hwi_loc (loc, *n2, -1);
  82       else
  83         *n2 = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (*n2), *n2,
  84                                build_int_cst (TREE_TYPE (*n2), 1));
  85       *cond_code = GT_EXPR;
  86       break;
  87     default:
  88       gcc_unreachable ();
  89     }
  90 }
  91
  92 /* Return the looping step from INCR, extracted from the step of a gimple omp
  93    for statement.  */
  94
  95 tree
  96 omp_get_for_step_from_incr (location_t loc, tree incr)
  97 {
  98   tree step;
  99   switch (TREE_CODE (incr))
 100     {
 101     case PLUS_EXPR:
 102       step = TREE_OPERAND (incr, 1);
 103       break;
 104     case POINTER_PLUS_EXPR:
 105       step = fold_convert (ssizetype, TREE_OPERAND (incr, 1));
 106       break;
 107     case MINUS_EXPR:
 108       step = TREE_OPERAND (incr, 1);
 109       step = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (step), step);
 110       break;
 111     default:
 112       gcc_unreachable ();
 113     }
 114   return step;
 115 }
 116
 117 /* Extract the header elements of parallel loop FOR_STMT and store
 118    them into *FD.  */
 119
 120 void
 121 omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
 122                       struct omp_for_data_loop *loops)
 123 {
 124   tree t, var, *collapse_iter, *collapse_count;
 125   tree count = NULL_TREE, iter_type = long_integer_type_node;
 126   struct omp_for_data_loop *loop;
 127   int i;
 128   struct omp_for_data_loop dummy_loop;
 129   location_t loc = gimple_location (for_stmt);
 130   bool simd = gimple_omp_for_kind (for_stmt) & GF_OMP_FOR_SIMD;
 131   bool distribute = gimple_omp_for_kind (for_stmt)
 132                     == GF_OMP_FOR_KIND_DISTRIBUTE;
 133   bool taskloop = gimple_omp_for_kind (for_stmt)
 134                   == GF_OMP_FOR_KIND_TASKLOOP;
 135   tree iterv, countv;
 136
 137   fd->for_stmt = for_stmt;
 138   fd->pre = NULL;
 139   fd->have_nowait = distribute || simd;
 140   fd->have_ordered = false;
 141   fd->have_reductemp = false;
 142   fd->tiling = NULL_TREE;
 143   fd->collapse = 1;
 144   fd->ordered = 0;
 145   fd->sched_kind = OMP_CLAUSE_SCHEDULE_STATIC;
 146   fd->sched_modifiers = 0;
 147   fd->chunk_size = NULL_TREE;
 148   fd->simd_schedule = false;
 149   collapse_iter = NULL;
 150   collapse_count = NULL;
 151
 152   for (t = gimple_omp_for_clauses (for_stmt); t ; t = OMP_CLAUSE_CHAIN (t))
 153     switch (OMP_CLAUSE_CODE (t))
 154       {
 155       case OMP_CLAUSE_NOWAIT:
 156         fd->have_nowait = true;
 157         break;
 158       case OMP_CLAUSE_ORDERED:
 159         fd->have_ordered = true;
 160         if (OMP_CLAUSE_ORDERED_EXPR (t))
 161           fd->ordered = tree_to_shwi (OMP_CLAUSE_ORDERED_EXPR (t));
 162         break;
 163       case OMP_CLAUSE_SCHEDULE:
 164         gcc_assert (!distribute && !taskloop);
 165         fd->sched_kind
 166           = (enum omp_clause_schedule_kind)
 167             (OMP_CLAUSE_SCHEDULE_KIND (t) & OMP_CLAUSE_SCHEDULE_MASK);
 168         fd->sched_modifiers = (OMP_CLAUSE_SCHEDULE_KIND (t)
 169                                & ~OMP_CLAUSE_SCHEDULE_MASK);
 170         fd->chunk_size = OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (t);
 171         fd->simd_schedule = OMP_CLAUSE_SCHEDULE_SIMD (t);
 172         break;
 173       case OMP_CLAUSE_DIST_SCHEDULE:
 174         gcc_assert (distribute);
 175         fd->chunk_size = OMP_CLAUSE_DIST_SCHEDULE_CHUNK_EXPR (t);
 176         break;
 177       case OMP_CLAUSE_COLLAPSE:
 178         fd->collapse = tree_to_shwi (OMP_CLAUSE_COLLAPSE_EXPR (t));
 179         if (fd->collapse > 1)
 180           {
 181             collapse_iter = &OMP_CLAUSE_COLLAPSE_ITERVAR (t);
 182             collapse_count = &OMP_CLAUSE_COLLAPSE_COUNT (t);
 183           }
 184         break;
 185       case OMP_CLAUSE_TILE:
 186         fd->tiling = OMP_CLAUSE_TILE_LIST (t);
 187         fd->collapse = list_length (fd->tiling);
 188         gcc_assert (fd->collapse);
 189         collapse_iter = &OMP_CLAUSE_TILE_ITERVAR (t);
 190         collapse_count = &OMP_CLAUSE_TILE_COUNT (t);
 191         break;
 192       case OMP_CLAUSE__REDUCTEMP_:
 193         fd->have_reductemp = true;
 194       default:
 195         break;
 196       }
 197
 198   if (fd->collapse > 1 || fd->tiling)
 199     fd->loops = loops;
 200   else
 201     fd->loops = &fd->loop;
 202
 203   if (fd->ordered && fd->collapse == 1 && loops != NULL)
 204     {
 205       fd->loops = loops;
 206       iterv = NULL_TREE;
 207       countv = NULL_TREE;
 208       collapse_iter = &iterv;
 209       collapse_count = &countv;
 210     }
 211
 212   /* FIXME: for now map schedule(auto) to schedule(static).
 213      There should be analysis to determine whether all iterations
 214      are approximately the same amount of work (then schedule(static)
 215      is best) or if it varies (then schedule(dynamic,N) is better).  */
 216   if (fd->sched_kind == OMP_CLAUSE_SCHEDULE_AUTO)
 217     {
 218       fd->sched_kind = OMP_CLAUSE_SCHEDULE_STATIC;
 219       gcc_assert (fd->chunk_size == NULL);
 220     }
 221   gcc_assert ((fd->collapse == 1 && !fd->tiling) || collapse_iter != NULL);
 222   if (taskloop)
 223     fd->sched_kind = OMP_CLAUSE_SCHEDULE_RUNTIME;
 224   if (fd->sched_kind == OMP_CLAUSE_SCHEDULE_RUNTIME)
 225     gcc_assert (fd->chunk_size == NULL);
 226   else if (fd->chunk_size == NULL)
 227     {
 228       /* We only need to compute a default chunk size for ordered
 229          static loops and dynamic loops.  */
 230       if (fd->sched_kind != OMP_CLAUSE_SCHEDULE_STATIC
 231           || fd->have_ordered)
 232         fd->chunk_size = (fd->sched_kind == OMP_CLAUSE_SCHEDULE_STATIC)
 233                          ? integer_zero_node : integer_one_node;
 234     }
 235
 236   int cnt = fd->ordered ? fd->ordered : fd->collapse;
 237   for (i = 0; i < cnt; i++)
 238     {
 239       if (i == 0
 240           && fd->collapse == 1
 241           && !fd->tiling
 242           && (fd->ordered == 0 || loops == NULL))
 243         loop = &fd->loop;
 244       else if (loops != NULL)
 245         loop = loops + i;
 246       else
 247         loop = &dummy_loop;
 248
 249       loop->v = gimple_omp_for_index (for_stmt, i);
 250       gcc_assert (SSA_VAR_P (loop->v));
 251       gcc_assert (TREE_CODE (TREE_TYPE (loop->v)) == INTEGER_TYPE
 252                   || TREE_CODE (TREE_TYPE (loop->v)) == POINTER_TYPE);
 253       var = TREE_CODE (loop->v) == SSA_NAME ? SSA_NAME_VAR (loop->v) : loop->v;
 254       loop->n1 = gimple_omp_for_initial (for_stmt, i);
 255
 256       loop->cond_code = gimple_omp_for_cond (for_stmt, i);
 257       loop->n2 = gimple_omp_for_final (for_stmt, i);
 258       gcc_assert (loop->cond_code != NE_EXPR
 259                   || (gimple_omp_for_kind (for_stmt)
 260                       != GF_OMP_FOR_KIND_OACC_LOOP));
 261       omp_adjust_for_condition (loc, &loop->cond_code, &loop->n2);
 262
 263       t = gimple_omp_for_incr (for_stmt, i);
 264       gcc_assert (TREE_OPERAND (t, 0) == var);
 265       loop->step = omp_get_for_step_from_incr (loc, t);
 266
 267       if (loop->cond_code == NE_EXPR)
 268         {
 269           gcc_assert (TREE_CODE (loop->step) == INTEGER_CST);
 270           if (TREE_CODE (TREE_TYPE (loop->v)) == INTEGER_TYPE)
 271             {
 272               if (integer_onep (loop->step))
 273                 loop->cond_code = LT_EXPR;
 274               else
 275                 {
 276                   gcc_assert (integer_minus_onep (loop->step));
 277                   loop->cond_code = GT_EXPR;
 278                 }
 279             }
 280           else
 281             {
 282               tree unit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (loop->v)));
 283               gcc_assert (TREE_CODE (unit) == INTEGER_CST);
 284               if (tree_int_cst_equal (unit, loop->step))
 285                 loop->cond_code = LT_EXPR;
 286               else
 287                 {
 288                   gcc_assert (wi::neg (wi::to_widest (unit))
 289                               == wi::to_widest (loop->step));
 290                   loop->cond_code = GT_EXPR;
 291                 }
 292             }
 293         }
 294
 295       omp_adjust_for_condition (loc, &loop->cond_code, &loop->n2);
 296
 297       if (simd
 298           || (fd->sched_kind == OMP_CLAUSE_SCHEDULE_STATIC
 299               && !fd->have_ordered))
 300         {
 301           if (fd->collapse == 1 && !fd->tiling)
 302             iter_type = TREE_TYPE (loop->v);
 303           else if (i == 0
 304                    || TYPE_PRECISION (iter_type)
 305                       < TYPE_PRECISION (TREE_TYPE (loop->v)))
 306             iter_type
 307               = build_nonstandard_integer_type
 308                   (TYPE_PRECISION (TREE_TYPE (loop->v)), 1);
 309         }
 310       else if (iter_type != long_long_unsigned_type_node)
 311         {
 312           if (POINTER_TYPE_P (TREE_TYPE (loop->v)))
 313             iter_type = long_long_unsigned_type_node;
 314           else if (TYPE_UNSIGNED (TREE_TYPE (loop->v))
 315                    && TYPE_PRECISION (TREE_TYPE (loop->v))
 316                       >= TYPE_PRECISION (iter_type))
 317             {
 318               tree n;
 319
 320               if (loop->cond_code == LT_EXPR)
 321                 n = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (loop->v),
 322                                      loop->n2, loop->step);
 323               else
 324                 n = loop->n1;
 325               if (TREE_CODE (n) != INTEGER_CST
 326                   || tree_int_cst_lt (TYPE_MAX_VALUE (iter_type), n))
 327                 iter_type = long_long_unsigned_type_node;
 328             }
 329           else if (TYPE_PRECISION (TREE_TYPE (loop->v))
 330                    > TYPE_PRECISION (iter_type))
 331             {
 332               tree n1, n2;
 333
 334               if (loop->cond_code == LT_EXPR)
 335                 {
 336                   n1 = loop->n1;
 337                   n2 = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (loop->v),
 338                                         loop->n2, loop->step);
 339                 }
 340               else
 341                 {
 342                   n1 = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (loop->v),
 343                                         loop->n2, loop->step);
 344                   n2 = loop->n1;
 345                 }
 346               if (TREE_CODE (n1) != INTEGER_CST
 347                   || TREE_CODE (n2) != INTEGER_CST
 348                   || !tree_int_cst_lt (TYPE_MIN_VALUE (iter_type), n1)
 349                   || !tree_int_cst_lt (n2, TYPE_MAX_VALUE (iter_type)))
 350                 iter_type = long_long_unsigned_type_node;
 351             }
 352         }
 353
 354       if (i >= fd->collapse)
 355         continue;
 356
 357       if (collapse_count && *collapse_count == NULL)
 358         {
 359           t = fold_binary (loop->cond_code, boolean_type_node,
 360                            fold_convert (TREE_TYPE (loop->v), loop->n1),
 361                            fold_convert (TREE_TYPE (loop->v), loop->n2));
 362           if (t && integer_zerop (t))
 363             count = build_zero_cst (long_long_unsigned_type_node);
 364           else if ((i == 0 || count != NULL_TREE)
 365                    && TREE_CODE (TREE_TYPE (loop->v)) == INTEGER_TYPE
 366                    && TREE_CONSTANT (loop->n1)
 367                    && TREE_CONSTANT (loop->n2)
 368                    && TREE_CODE (loop->step) == INTEGER_CST)
 369             {
 370               tree itype = TREE_TYPE (loop->v);
 371
 372               if (POINTER_TYPE_P (itype))
 373                 itype = signed_type_for (itype);
 374               t = build_int_cst (itype, (loop->cond_code == LT_EXPR ? -1 : 1));
 375               t = fold_build2_loc (loc, PLUS_EXPR, itype,
 376                                    fold_convert_loc (loc, itype, loop->step),
 377                                    t);
 378               t = fold_build2_loc (loc, PLUS_EXPR, itype, t,
 379                                    fold_convert_loc (loc, itype, loop->n2));
 380               t = fold_build2_loc (loc, MINUS_EXPR, itype, t,
 381                                    fold_convert_loc (loc, itype, loop->n1));
 382               if (TYPE_UNSIGNED (itype) && loop->cond_code == GT_EXPR)
 383                 {
 384                   tree step = fold_convert_loc (loc, itype, loop->step);
 385                   t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
 386                                        fold_build1_loc (loc, NEGATE_EXPR,
 387                                                         itype, t),
 388                                        fold_build1_loc (loc, NEGATE_EXPR,
 389                                                         itype, step));
 390                 }
 391               else
 392                 t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
 393                                      fold_convert_loc (loc, itype,
 394                                                        loop->step));
 395               t = fold_convert_loc (loc, long_long_unsigned_type_node, t);
 396               if (count != NULL_TREE)
 397                 count = fold_build2_loc (loc, MULT_EXPR,
 398                                          long_long_unsigned_type_node,
 399                                          count, t);
 400               else
 401                 count = t;
 402               if (TREE_CODE (count) != INTEGER_CST)
 403                 count = NULL_TREE;
 404             }
 405           else if (count && !integer_zerop (count))
 406             count = NULL_TREE;
 407         }
 408     }
 409
 410   if (count
 411       && !simd
 412       && (fd->sched_kind != OMP_CLAUSE_SCHEDULE_STATIC
 413           || fd->have_ordered))
 414     {
 415       if (!tree_int_cst_lt (count, TYPE_MAX_VALUE (long_integer_type_node)))
 416         iter_type = long_long_unsigned_type_node;
 417       else
 418         iter_type = long_integer_type_node;
 419     }
 420   else if (collapse_iter && *collapse_iter != NULL)
 421     iter_type = TREE_TYPE (*collapse_iter);
 422   fd->iter_type = iter_type;
 423   if (collapse_iter && *collapse_iter == NULL)
 424     *collapse_iter = create_tmp_var (iter_type, ".iter");
 425   if (collapse_count && *collapse_count == NULL)
 426     {
 427       if (count)
 428         *collapse_count = fold_convert_loc (loc, iter_type, count);
 429       else
 430         *collapse_count = create_tmp_var (iter_type, ".count");
 431     }
 432
 433   if (fd->collapse > 1 || fd->tiling || (fd->ordered && loops))
 434     {
 435       fd->loop.v = *collapse_iter;
 436       fd->loop.n1 = build_int_cst (TREE_TYPE (fd->loop.v), 0);
 437       fd->loop.n2 = *collapse_count;
 438       fd->loop.step = build_int_cst (TREE_TYPE (fd->loop.v), 1);
 439       fd->loop.cond_code = LT_EXPR;
 440     }
 441   else if (loops)
 442     loops[0] = fd->loop;
 443 }
 444
 445 /* Build a call to GOMP_barrier.  */
 446
 447 gimple *
 448 omp_build_barrier (tree lhs)
 449 {
 450   tree fndecl = builtin_decl_explicit (lhs ? BUILT_IN_GOMP_BARRIER_CANCEL
 451                                            : BUILT_IN_GOMP_BARRIER);
 452   gcall *g = gimple_build_call (fndecl, 0);
 453   if (lhs)
 454     gimple_call_set_lhs (g, lhs);
 455   return g;
 456 }
 457
 458 /* Return maximum possible vectorization factor for the target.  */
 459
 460 poly_uint64
 461 omp_max_vf (void)
 462 {
 463   if (!optimize
 464       || optimize_debug
 465       || !flag_tree_loop_optimize
 466       || (!flag_tree_loop_vectorize
 467           && global_options_set.x_flag_tree_loop_vectorize))
 468     return 1;
 469
 470   auto_vector_sizes sizes;
 471   targetm.vectorize.autovectorize_vector_sizes (&sizes);
 472   if (!sizes.is_empty ())
 473     {
 474       poly_uint64 vf = 0;
 475       for (unsigned int i = 0; i < sizes.length (); ++i)
 476         vf = ordered_max (vf, sizes[i]);
 477       return vf;
 478     }
 479
 480   machine_mode vqimode = targetm.vectorize.preferred_simd_mode (QImode);
 481   if (GET_MODE_CLASS (vqimode) == MODE_VECTOR_INT)
 482     return GET_MODE_NUNITS (vqimode);
 483
 484   return 1;
 485 }
 486
 487 /* Return maximum SIMT width if offloading may target SIMT hardware.  */
 488
 489 int
 490 omp_max_simt_vf (void)
 491 {
 492   if (!optimize)
 493     return 0;
 494   if (ENABLE_OFFLOADING)
 495     for (const char *c = getenv ("OFFLOAD_TARGET_NAMES"); c;)
 496       {
 497         if (!strncmp (c, "nvptx", strlen ("nvptx")))
 498           return 32;
 499         else if ((c = strchr (c, ',')))
 500           c++;
 501       }
 502   return 0;
 503 }
 504
 505 /* Encode an oacc launch argument.  This matches the GOMP_LAUNCH_PACK
 506    macro on gomp-constants.h.  We do not check for overflow.  */
 507
 508 tree
 509 oacc_launch_pack (unsigned code, tree device, unsigned op)
 510 {
 511   tree res;
 512
 513   res = build_int_cst (unsigned_type_node, GOMP_LAUNCH_PACK (code, 0, op));
 514   if (device)
 515     {
 516       device = fold_build2 (LSHIFT_EXPR, unsigned_type_node,
 517                             device, build_int_cst (unsigned_type_node,
 518                                                    GOMP_LAUNCH_DEVICE_SHIFT));
 519       res = fold_build2 (BIT_IOR_EXPR, unsigned_type_node, res, device);
 520     }
 521   return res;
 522 }
 523
 524 /* FIXME: What is the following comment for? */
 525 /* Look for compute grid dimension clauses and convert to an attribute
 526    attached to FN.  This permits the target-side code to (a) massage
 527    the dimensions, (b) emit that data and (c) optimize.  Non-constant
 528    dimensions are pushed onto ARGS.
 529
 530    The attribute value is a TREE_LIST.  A set of dimensions is
 531    represented as a list of INTEGER_CST.  Those that are runtime
 532    exprs are represented as an INTEGER_CST of zero.
 533
 534    TODO: Normally the attribute will just contain a single such list.  If
 535    however it contains a list of lists, this will represent the use of
 536    device_type.  Each member of the outer list is an assoc list of
 537    dimensions, keyed by the device type.  The first entry will be the
 538    default.  Well, that's the plan.  */
 539
 540 /* Replace any existing oacc fn attribute with updated dimensions.  */
 541
 542 void
 543 oacc_replace_fn_attrib (tree fn, tree dims)
 544 {
 545   tree ident = get_identifier (OACC_FN_ATTRIB);
 546   tree attribs = DECL_ATTRIBUTES (fn);
 547
 548   /* If we happen to be present as the first attrib, drop it.  */
 549   if (attribs && TREE_PURPOSE (attribs) == ident)
 550     attribs = TREE_CHAIN (attribs);
 551   DECL_ATTRIBUTES (fn) = tree_cons (ident, dims, attribs);
 552 }
 553
 554 /* Scan CLAUSES for launch dimensions and attach them to the oacc
 555    function attribute.  Push any that are non-constant onto the ARGS
 556    list, along with an appropriate GOMP_LAUNCH_DIM tag.  */
 557
 558 void
 559 oacc_set_fn_attrib (tree fn, tree clauses, vec<tree> *args)
 560 {
 561   /* Must match GOMP_DIM ordering.  */
 562   static const omp_clause_code ids[]
 563     = { OMP_CLAUSE_NUM_GANGS, OMP_CLAUSE_NUM_WORKERS,
 564         OMP_CLAUSE_VECTOR_LENGTH };
 565   unsigned ix;
 566   tree dims[GOMP_DIM_MAX];
 567
 568   tree attr = NULL_TREE;
 569   unsigned non_const = 0;
 570
 571   for (ix = GOMP_DIM_MAX; ix--;)
 572     {
 573       tree clause = omp_find_clause (clauses, ids[ix]);
 574       tree dim = NULL_TREE;
 575
 576       if (clause)
 577         dim = OMP_CLAUSE_EXPR (clause, ids[ix]);
 578       dims[ix] = dim;
 579       if (dim && TREE_CODE (dim) != INTEGER_CST)
 580         {
 581           dim = integer_zero_node;
 582           non_const |= GOMP_DIM_MASK (ix);
 583         }
 584       attr = tree_cons (NULL_TREE, dim, attr);
 585     }
 586
 587   oacc_replace_fn_attrib (fn, attr);
 588
 589   if (non_const)
 590     {
 591       /* Push a dynamic argument set.  */
 592       args->safe_push (oacc_launch_pack (GOMP_LAUNCH_DIM,
 593                                          NULL_TREE, non_const));
 594       for (unsigned ix = 0; ix != GOMP_DIM_MAX; ix++)
 595         if (non_const & GOMP_DIM_MASK (ix))
 596           args->safe_push (dims[ix]);
 597     }
 598 }
 599
 600 /*  Process the routine's dimension clauess to generate an attribute
 601     value.  Issue diagnostics as appropriate.  We default to SEQ
 602     (OpenACC 2.5 clarifies this). All dimensions have a size of zero
 603     (dynamic).  TREE_PURPOSE is set to indicate whether that dimension
 604     can have a loop partitioned on it.  non-zero indicates
 605     yes, zero indicates no.  By construction once a non-zero has been
 606     reached, further inner dimensions must also be non-zero.  We set
 607     TREE_VALUE to zero for the dimensions that may be partitioned and
 608     1 for the other ones -- if a loop is (erroneously) spawned at
 609     an outer level, we don't want to try and partition it.  */
 610
 611 tree
 612 oacc_build_routine_dims (tree clauses)
 613 {
 614   /* Must match GOMP_DIM ordering.  */
 615   static const omp_clause_code ids[]
 616     = {OMP_CLAUSE_GANG, OMP_CLAUSE_WORKER, OMP_CLAUSE_VECTOR, OMP_CLAUSE_SEQ};
 617   int ix;
 618   int level = -1;
 619
 620   for (; clauses; clauses = OMP_CLAUSE_CHAIN (clauses))
 621     for (ix = GOMP_DIM_MAX + 1; ix--;)
 622       if (OMP_CLAUSE_CODE (clauses) == ids[ix])
 623         {
 624           if (level >= 0)
 625             error_at (OMP_CLAUSE_LOCATION (clauses),
 626                       "multiple loop axes specified for routine");
 627           level = ix;
 628           break;
 629         }
 630
 631   /* Default to SEQ.  */
 632   if (level < 0)
 633     level = GOMP_DIM_MAX;
 634
 635   tree dims = NULL_TREE;
 636
 637   for (ix = GOMP_DIM_MAX; ix--;)
 638     dims = tree_cons (build_int_cst (boolean_type_node, ix >= level),
 639                       build_int_cst (integer_type_node, ix < level), dims);
 640
 641   return dims;
 642 }
 643
 644 /* Retrieve the oacc function attrib and return it.  Non-oacc
 645    functions will return NULL.  */
 646
 647 tree
 648 oacc_get_fn_attrib (tree fn)
 649 {
 650   return lookup_attribute (OACC_FN_ATTRIB, DECL_ATTRIBUTES (fn));
 651 }
 652
 653 /* Return true if FN is an OpenMP or OpenACC offloading function.  */
 654
 655 bool
 656 offloading_function_p (tree fn)
 657 {
 658   tree attrs = DECL_ATTRIBUTES (fn);
 659   return (lookup_attribute ("omp declare target", attrs)
 660           || lookup_attribute ("omp target entrypoint", attrs));
 661 }
 662
 663 /* Extract an oacc execution dimension from FN.  FN must be an
 664    offloaded function or routine that has already had its execution
 665    dimensions lowered to the target-specific values.  */
 666
 667 int
 668 oacc_get_fn_dim_size (tree fn, int axis)
 669 {
 670   tree attrs = oacc_get_fn_attrib (fn);
 671
 672   gcc_assert (axis < GOMP_DIM_MAX);
 673
 674   tree dims = TREE_VALUE (attrs);
 675   while (axis--)
 676     dims = TREE_CHAIN (dims);
 677
 678   int size = TREE_INT_CST_LOW (TREE_VALUE (dims));
 679
 680   return size;
 681 }
 682
 683 /* Extract the dimension axis from an IFN_GOACC_DIM_POS or
 684    IFN_GOACC_DIM_SIZE call.  */
 685
 686 int
 687 oacc_get_ifn_dim_arg (const gimple *stmt)
 688 {
 689   gcc_checking_assert (gimple_call_internal_fn (stmt) == IFN_GOACC_DIM_SIZE
 690                        || gimple_call_internal_fn (stmt) == IFN_GOACC_DIM_POS);
 691   tree arg = gimple_call_arg (stmt, 0);
 692   HOST_WIDE_INT axis = TREE_INT_CST_LOW (arg);
 693
 694   gcc_checking_assert (axis >= 0 && axis < GOMP_DIM_MAX);
 695   return (int) axis;
 696 }