gcc/graphite.h

   1 /* Graphite polyhedral representation.
   2    Copyright (C) 2009-2021 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <sebastian.pop@amd.com> and
   4    Tobias Grosser <grosser@fim.uni-passau.de>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License 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 #ifndef GCC_GRAPHITE_POLY_H
  23 #define GCC_GRAPHITE_POLY_H
  24
  25 #include "sese.h"
  26
  27 typedef struct poly_dr *poly_dr_p;
  28
  29 typedef struct poly_bb *poly_bb_p;
  30
  31 typedef struct scop *scop_p;
  32
  33 typedef unsigned graphite_dim_t;
  34
  35 static inline graphite_dim_t scop_nb_params (scop_p);
  36
  37 /* A data reference can write or read some memory or we
  38    just know it may write some memory.  */
  39 enum poly_dr_type
  40 {
  41   PDR_READ,
  42   /* PDR_MAY_READs are represented using PDR_READS.  This does not
  43      limit the expressiveness.  */
  44   PDR_WRITE,
  45   PDR_MAY_WRITE
  46 };
  47
  48 struct poly_dr
  49 {
  50   /* An identifier for this PDR.  */
  51   int id;
  52
  53   /* The number of data refs identical to this one in the PBB.  */
  54   int nb_refs;
  55
  56   /* A pointer to the gimple stmt containing this reference.  */
  57   gimple *stmt;
  58
  59   /* A pointer to the PBB that contains this data reference.  */
  60   poly_bb_p pbb;
  61
  62   enum poly_dr_type type;
  63
  64   /* The access polyhedron contains the polyhedral space this data
  65      reference will access.
  66
  67      The polyhedron contains these dimensions:
  68
  69      - The alias set (a):
  70      Every memory access is classified in at least one alias set.
  71
  72      - The subscripts (s_0, ..., s_n):
  73      The memory is accessed using zero or more subscript dimensions.
  74
  75      - The iteration domain (variables and parameters)
  76
  77      Do not hardcode the dimensions.  Use the following accessor functions:
  78      - pdr_alias_set_dim
  79      - pdr_subscript_dim
  80      - pdr_iterator_dim
  81      - pdr_parameter_dim
  82
  83      Example:
  84
  85      | int A[1335][123];
  86      | int *p = malloc ();
  87      |
  88      | k = ...
  89      | for i
  90      |   {
  91      |     if (unknown_function ())
  92      |       p = A;
  93      |       ... = p[?][?];
  94      |     for j
  95      |       A[i][j+k] = m;
  96      |   }
  97
  98      The data access A[i][j+k] in alias set "5" is described like this:
  99
 100      | i   j   k   a  s0  s1   1
 101      | 0   0   0   1   0   0  -5     =  0
 102      |-1   0   0   0   1   0   0     =  0
 103      | 0  -1  -1   0   0   1   0     =  0
 104      | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
 105      | 0   0   0   0   0   1   0     >= 0  # array size.
 106      | 0   0   0   0  -1   0 1335    >= 0
 107      | 0   0   0   0   0  -1 123     >= 0
 108
 109      The pointer "*p" in alias set "5" and "7" is described as a union of
 110      polyhedron:
 111
 112
 113      | i   k   a  s0   1
 114      | 0   0   1   0  -5   =  0
 115      | 0   0   0   1   0   >= 0
 116
 117      "or"
 118
 119      | i   k   a  s0   1
 120      | 0   0   1   0  -7   =  0
 121      | 0   0   0   1   0   >= 0
 122
 123      "*p" accesses all of the object allocated with 'malloc'.
 124
 125      The scalar data access "m" is represented as an array with zero subscript
 126      dimensions.
 127
 128      | i   j   k   a   1
 129      | 0   0   0  -1   15  = 0
 130
 131      The difference between the graphite internal format for access data and
 132      the OpenSop format is in the order of columns.
 133      Instead of having:
 134
 135      | i   j   k   a  s0  s1   1
 136      | 0   0   0   1   0   0  -5     =  0
 137      |-1   0   0   0   1   0   0     =  0
 138      | 0  -1  -1   0   0   1   0     =  0
 139      | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
 140      | 0   0   0   0   0   1   0     >= 0  # array size.
 141      | 0   0   0   0  -1   0 1335    >= 0
 142      | 0   0   0   0   0  -1 123     >= 0
 143
 144      In OpenScop we have:
 145
 146      | a  s0  s1   i   j   k   1
 147      | 1   0   0   0   0   0  -5     =  0
 148      | 0   1   0  -1   0   0   0     =  0
 149      | 0   0   1   0  -1  -1   0     =  0
 150      | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
 151      | 0   0   1   0   0   0   0     >= 0  # array size.
 152      | 0  -1   0   0   0   0 1335    >= 0
 153      | 0   0  -1   0   0   0 123     >= 0
 154
 155      The OpenScop access function is printed as follows:
 156
 157      | 1  # The number of disjunct components in a union of access functions.
 158      | R C O I L P  # Described bellow.
 159      | a  s0  s1   i   j   k   1
 160      | 1   0   0   0   0   0  -5     =  0
 161      | 0   1   0  -1   0   0   0     =  0
 162      | 0   0   1   0  -1  -1   0     =  0
 163      | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
 164      | 0   0   1   0   0   0   0     >= 0  # array size.
 165      | 0  -1   0   0   0   0 1335    >= 0
 166      | 0   0  -1   0   0   0 123     >= 0
 167
 168      Where:
 169      - R: Number of rows.
 170      - C: Number of columns.
 171      - O: Number of output dimensions = alias set + number of subscripts.
 172      - I: Number of input dimensions (iterators).
 173      - L: Number of local (existentially quantified) dimensions.
 174      - P: Number of parameters.
 175
 176      In the example, the vector "R C O I L P" is "7 7 3 2 0 1".  */
 177   isl_map *accesses;
 178   isl_set *subscript_sizes;
 179 };
 180
 181 #define PDR_ID(PDR) (PDR->id)
 182 #define PDR_NB_REFS(PDR) (PDR->nb_refs)
 183 #define PDR_PBB(PDR) (PDR->pbb)
 184 #define PDR_TYPE(PDR) (PDR->type)
 185 #define PDR_ACCESSES(PDR) (NULL)
 186
 187 void new_poly_dr (poly_bb_p, gimple *, enum poly_dr_type,
 188                   isl_map *, isl_set *);
 189 void debug_pdr (poly_dr_p);
 190 void print_pdr (FILE *, poly_dr_p);
 191
 192 static inline bool
 193 pdr_read_p (poly_dr_p pdr)
 194 {
 195   return PDR_TYPE (pdr) == PDR_READ;
 196 }
 197
 198 /* Returns true when PDR is a "write".  */
 199
 200 static inline bool
 201 pdr_write_p (poly_dr_p pdr)
 202 {
 203   return PDR_TYPE (pdr) == PDR_WRITE;
 204 }
 205
 206 /* Returns true when PDR is a "may write".  */
 207
 208 static inline bool
 209 pdr_may_write_p (poly_dr_p pdr)
 210 {
 211   return PDR_TYPE (pdr) == PDR_MAY_WRITE;
 212 }
 213
 214 /* POLY_BB represents a blackbox in the polyhedral model.  */
 215
 216 struct poly_bb
 217 {
 218   /* Pointer to a basic block or a statement in the compiler.  */
 219   gimple_poly_bb_p black_box;
 220
 221   /* Pointer to the SCOP containing this PBB.  */
 222   scop_p scop;
 223
 224   /* The iteration domain of this bb.  The layout of this polyhedron
 225      is I|G with I the iteration domain, G the context parameters.
 226
 227      Example:
 228
 229      for (i = a - 7*b + 8; i <= 3*a + 13*b + 20; i++)
 230        for (j = 2; j <= 2*i + 5; j++)
 231          for (k = 0; k <= 5; k++)
 232            S (i,j,k)
 233
 234      Loop iterators: i, j, k
 235      Parameters: a, b
 236
 237      | i >=  a -  7b +  8
 238      | i <= 3a + 13b + 20
 239      | j >= 2
 240      | j <= 2i + 5
 241      | k >= 0
 242      | k <= 5
 243
 244      The number of variables in the DOMAIN may change and is not
 245      related to the number of loops in the original code.  */
 246   isl_set *domain;
 247   isl_set *iterators;
 248
 249   /* The data references we access.  */
 250   vec<poly_dr_p> drs;
 251
 252   /* The last basic block generated for this pbb.  */
 253   basic_block new_bb;
 254 };
 255
 256 #define PBB_BLACK_BOX(PBB) ((gimple_poly_bb_p) PBB->black_box)
 257 #define PBB_SCOP(PBB) (PBB->scop)
 258 #define PBB_DRS(PBB) (PBB->drs)
 259
 260 extern poly_bb_p new_poly_bb (scop_p, gimple_poly_bb_p);
 261 extern void print_pbb_domain (FILE *, poly_bb_p);
 262 extern void print_pbb (FILE *, poly_bb_p);
 263 extern void print_scop_context (FILE *, scop_p);
 264 extern void print_scop (FILE *, scop_p);
 265 extern void debug_pbb_domain (poly_bb_p);
 266 extern void debug_pbb (poly_bb_p);
 267 extern void print_pdrs (FILE *, poly_bb_p);
 268 extern void debug_pdrs (poly_bb_p);
 269 extern void debug_scop_context (scop_p);
 270 extern void debug_scop (scop_p);
 271 extern void print_scop_params (FILE *, scop_p);
 272 extern void debug_scop_params (scop_p);
 273 extern void print_iteration_domain (FILE *, poly_bb_p);
 274 extern void print_iteration_domains (FILE *, scop_p);
 275 extern void debug_iteration_domain (poly_bb_p);
 276 extern void debug_iteration_domains (scop_p);
 277 extern void print_isl_set (FILE *, isl_set *);
 278 extern void print_isl_map (FILE *, isl_map *);
 279 extern void print_isl_union_map (FILE *, isl_union_map *);
 280 extern void print_isl_aff (FILE *, isl_aff *);
 281 extern void print_isl_constraint (FILE *, isl_constraint *);
 282 extern void print_isl_schedule (FILE *, isl_schedule *);
 283 extern void debug_isl_schedule (isl_schedule *);
 284 extern void print_isl_ast (FILE *, isl_ast_node *);
 285 extern void debug_isl_ast (isl_ast_node *);
 286 extern void debug_isl_set (isl_set *);
 287 extern void debug_isl_map (isl_map *);
 288 extern void debug_isl_union_map (isl_union_map *);
 289 extern void debug_isl_aff (isl_aff *);
 290 extern void debug_isl_constraint (isl_constraint *);
 291 extern void debug_gmp_value (mpz_t);
 292 extern void debug_scop_pbb (scop_p scop, int i);
 293 extern void print_schedule_ast (FILE *, __isl_keep isl_schedule *, scop_p);
 294 extern void debug_schedule_ast (__isl_keep isl_schedule *, scop_p);
 295
 296 /* The basic block of the PBB.  */
 297
 298 static inline basic_block
 299 pbb_bb (poly_bb_p pbb)
 300 {
 301   return GBB_BB (PBB_BLACK_BOX (pbb));
 302 }
 303
 304 static inline int
 305 pbb_index (poly_bb_p pbb)
 306 {
 307   return pbb_bb (pbb)->index;
 308 }
 309
 310 /* The loop of the PBB.  */
 311
 312 static inline loop_p
 313 pbb_loop (poly_bb_p pbb)
 314 {
 315   return gbb_loop (PBB_BLACK_BOX (pbb));
 316 }
 317
 318 /* The scop that contains the PDR.  */
 319
 320 static inline scop_p
 321 pdr_scop (poly_dr_p pdr)
 322 {
 323   return PBB_SCOP (PDR_PBB (pdr));
 324 }
 325
 326 /* Set black box of PBB to BLACKBOX.  */
 327
 328 static inline void
 329 pbb_set_black_box (poly_bb_p pbb, gimple_poly_bb_p black_box)
 330 {
 331   pbb->black_box = black_box;
 332 }
 333
 334 /* A helper structure to keep track of data references, polyhedral BBs, and
 335    alias sets.  */
 336
 337 struct dr_info
 338 {
 339   enum {
 340     invalid_alias_set = -1
 341   };
 342   /* The data reference.  */
 343   data_reference_p dr;
 344
 345   /* The polyhedral BB containing this DR.  */
 346   poly_bb_p pbb;
 347
 348   /* ALIAS_SET is the SCC number assigned by a graph_dfs of the alias graph.
 349      -1 is an invalid alias set.  */
 350   int alias_set;
 351
 352   /* Construct a DR_INFO from a data reference DR, an ALIAS_SET, and a PBB.  */
 353   dr_info (data_reference_p dr, poly_bb_p pbb,
 354            int alias_set = invalid_alias_set)
 355     : dr (dr), pbb (pbb), alias_set (alias_set) {}
 356 };
 357
 358 /* A SCOP is a Static Control Part of the program, simple enough to be
 359    represented in polyhedral form.  */
 360 struct scop
 361 {
 362   /* A SCOP is defined as a SESE region.  */
 363   sese_info_p scop_info;
 364
 365   /* Number of parameters in SCoP.  */
 366   graphite_dim_t nb_params;
 367
 368   /* The maximum alias set as assigned to drs by build_alias_sets.  */
 369   unsigned max_alias_set;
 370
 371   /* All the basic blocks in this scop that contain memory references
 372      and that will be represented as statements in the polyhedral
 373      representation.  */
 374   vec<poly_bb_p> pbbs;
 375
 376   /* All the data references in this scop.  */
 377   vec<dr_info> drs;
 378
 379   /* The context describes known restrictions concerning the parameters
 380      and relations in between the parameters.
 381
 382   void f (int8_t a, uint_16_t b) {
 383     c = 2 a + b;
 384     ...
 385   }
 386
 387   Here we can add these restrictions to the context:
 388
 389   -128 >= a >= 127
 390      0 >= b >= 65,535
 391      c = 2a + b  */
 392   isl_set *param_context;
 393
 394   /* The context used internally by isl.  */
 395   isl_ctx *isl_context;
 396
 397   /* SCoP original schedule.  */
 398   isl_schedule *original_schedule;
 399
 400   /* SCoP transformed schedule.  */
 401   isl_schedule *transformed_schedule;
 402
 403   /* The data dependence relation among the data references in this scop.  */
 404   isl_union_map *dependence;
 405 };
 406
 407 extern scop_p new_scop (edge, edge);
 408 extern void free_scop (scop_p);
 409 extern gimple_poly_bb_p new_gimple_poly_bb (basic_block, vec<data_reference_p>,
 410                                             vec<scalar_use>, vec<tree>);
 411 extern bool apply_poly_transforms (scop_p);
 412
 413 /* Set the region of SCOP to REGION.  */
 414
 415 static inline void
 416 scop_set_region (scop_p scop, sese_info_p region)
 417 {
 418   scop->scop_info = region;
 419 }
 420
 421 /* Returns the number of parameters for SCOP.  */
 422
 423 static inline graphite_dim_t
 424 scop_nb_params (scop_p scop)
 425 {
 426   return scop->nb_params;
 427 }
 428
 429 /* Set the number of params of SCOP to NB_PARAMS.  */
 430
 431 static inline void
 432 scop_set_nb_params (scop_p scop, graphite_dim_t nb_params)
 433 {
 434   scop->nb_params = nb_params;
 435 }
 436
 437 extern void scop_get_dependences (scop_p scop);
 438
 439 bool
 440 carries_deps (__isl_keep isl_union_map *schedule,
 441               __isl_keep isl_union_map *deps,
 442               int depth);
 443
 444 extern bool build_poly_scop (scop_p);
 445 extern bool graphite_regenerate_ast_isl (scop_p);
 446 extern void build_scops (vec<scop_p> *);
 447 extern tree cached_scalar_evolution_in_region (const sese_l &, loop_p, tree);
 448 extern void dot_all_sese (FILE *, vec<sese_l> &);
 449 extern void dot_sese (sese_l &);
 450 extern void dot_cfg ();
 451
 452 #endif