gcc/graphite.h

   1 /* Graphite polyhedral representation.
   2    Copyright (C) 2009-2020 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 #include <isl/options.h>
  27 #include <isl/ctx.h>
  28 #include <isl/val.h>
  29 #include <isl/set.h>
  30 #include <isl/union_set.h>
  31 #include <isl/map.h>
  32 #include <isl/union_map.h>
  33 #include <isl/aff.h>
  34 #include <isl/constraint.h>
  35 #include <isl/flow.h>
  36 #include <isl/ilp.h>
  37 #include <isl/schedule.h>
  38 #include <isl/ast_build.h>
  39 #include <isl/schedule_node.h>
  40 #include <isl/id.h>
  41 #include <isl/space.h>
  42
  43 typedef struct poly_dr *poly_dr_p;
  44
  45 typedef struct poly_bb *poly_bb_p;
  46
  47 typedef struct scop *scop_p;
  48
  49 typedef unsigned graphite_dim_t;
  50
  51 static inline graphite_dim_t scop_nb_params (scop_p);
  52
  53 /* A data reference can write or read some memory or we
  54    just know it may write some memory.  */
  55 enum poly_dr_type
  56 {
  57   PDR_READ,
  58   /* PDR_MAY_READs are represented using PDR_READS.  This does not
  59      limit the expressiveness.  */
  60   PDR_WRITE,
  61   PDR_MAY_WRITE
  62 };
  63
  64 struct poly_dr
  65 {
  66   /* An identifier for this PDR.  */
  67   int id;
  68
  69   /* The number of data refs identical to this one in the PBB.  */
  70   int nb_refs;
  71
  72   /* A pointer to the gimple stmt containing this reference.  */
  73   gimple *stmt;
  74
  75   /* A pointer to the PBB that contains this data reference.  */
  76   poly_bb_p pbb;
  77
  78   enum poly_dr_type type;
  79
  80   /* The access polyhedron contains the polyhedral space this data
  81      reference will access.
  82
  83      The polyhedron contains these dimensions:
  84
  85      - The alias set (a):
  86      Every memory access is classified in at least one alias set.
  87
  88      - The subscripts (s_0, ..., s_n):
  89      The memory is accessed using zero or more subscript dimensions.
  90
  91      - The iteration domain (variables and parameters)
  92
  93      Do not hardcode the dimensions.  Use the following accessor functions:
  94      - pdr_alias_set_dim
  95      - pdr_subscript_dim
  96      - pdr_iterator_dim
  97      - pdr_parameter_dim
  98
  99      Example:
 100
 101      | int A[1335][123];
 102      | int *p = malloc ();
 103      |
 104      | k = ...
 105      | for i
 106      |   {
 107      |     if (unknown_function ())
 108      |       p = A;
 109      |       ... = p[?][?];
 110      |     for j
 111      |       A[i][j+k] = m;
 112      |   }
 113
 114      The data access A[i][j+k] in alias set "5" is described like this:
 115
 116      | i   j   k   a  s0  s1   1
 117      | 0   0   0   1   0   0  -5     =  0
 118      |-1   0   0   0   1   0   0     =  0
 119      | 0  -1  -1   0   0   1   0     =  0
 120      | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
 121      | 0   0   0   0   0   1   0     >= 0  # array size.
 122      | 0   0   0   0  -1   0 1335    >= 0
 123      | 0   0   0   0   0  -1 123     >= 0
 124
 125      The pointer "*p" in alias set "5" and "7" is described as a union of
 126      polyhedron:
 127
 128
 129      | i   k   a  s0   1
 130      | 0   0   1   0  -5   =  0
 131      | 0   0   0   1   0   >= 0
 132
 133      "or"
 134
 135      | i   k   a  s0   1
 136      | 0   0   1   0  -7   =  0
 137      | 0   0   0   1   0   >= 0
 138
 139      "*p" accesses all of the object allocated with 'malloc'.
 140
 141      The scalar data access "m" is represented as an array with zero subscript
 142      dimensions.
 143
 144      | i   j   k   a   1
 145      | 0   0   0  -1   15  = 0
 146
 147      The difference between the graphite internal format for access data and
 148      the OpenSop format is in the order of columns.
 149      Instead of having:
 150
 151      | i   j   k   a  s0  s1   1
 152      | 0   0   0   1   0   0  -5     =  0
 153      |-1   0   0   0   1   0   0     =  0
 154      | 0  -1  -1   0   0   1   0     =  0
 155      | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
 156      | 0   0   0   0   0   1   0     >= 0  # array size.
 157      | 0   0   0   0  -1   0 1335    >= 0
 158      | 0   0   0   0   0  -1 123     >= 0
 159
 160      In OpenScop we have:
 161
 162      | a  s0  s1   i   j   k   1
 163      | 1   0   0   0   0   0  -5     =  0
 164      | 0   1   0  -1   0   0   0     =  0
 165      | 0   0   1   0  -1  -1   0     =  0
 166      | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
 167      | 0   0   1   0   0   0   0     >= 0  # array size.
 168      | 0  -1   0   0   0   0 1335    >= 0
 169      | 0   0  -1   0   0   0 123     >= 0
 170
 171      The OpenScop access function is printed as follows:
 172
 173      | 1  # The number of disjunct components in a union of access functions.
 174      | R C O I L P  # Described bellow.
 175      | a  s0  s1   i   j   k   1
 176      | 1   0   0   0   0   0  -5     =  0
 177      | 0   1   0  -1   0   0   0     =  0
 178      | 0   0   1   0  -1  -1   0     =  0
 179      | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
 180      | 0   0   1   0   0   0   0     >= 0  # array size.
 181      | 0  -1   0   0   0   0 1335    >= 0
 182      | 0   0  -1   0   0   0 123     >= 0
 183
 184      Where:
 185      - R: Number of rows.
 186      - C: Number of columns.
 187      - O: Number of output dimensions = alias set + number of subscripts.
 188      - I: Number of input dimensions (iterators).
 189      - L: Number of local (existentially quantified) dimensions.
 190      - P: Number of parameters.
 191
 192      In the example, the vector "R C O I L P" is "7 7 3 2 0 1".  */
 193   isl_map *accesses;
 194   isl_set *subscript_sizes;
 195 };
 196
 197 #define PDR_ID(PDR) (PDR->id)
 198 #define PDR_NB_REFS(PDR) (PDR->nb_refs)
 199 #define PDR_PBB(PDR) (PDR->pbb)
 200 #define PDR_TYPE(PDR) (PDR->type)
 201 #define PDR_ACCESSES(PDR) (NULL)
 202
 203 void new_poly_dr (poly_bb_p, gimple *, enum poly_dr_type,
 204                   isl_map *, isl_set *);
 205 void debug_pdr (poly_dr_p);
 206 void print_pdr (FILE *, poly_dr_p);
 207
 208 static inline bool
 209 pdr_read_p (poly_dr_p pdr)
 210 {
 211   return PDR_TYPE (pdr) == PDR_READ;
 212 }
 213
 214 /* Returns true when PDR is a "write".  */
 215
 216 static inline bool
 217 pdr_write_p (poly_dr_p pdr)
 218 {
 219   return PDR_TYPE (pdr) == PDR_WRITE;
 220 }
 221
 222 /* Returns true when PDR is a "may write".  */
 223
 224 static inline bool
 225 pdr_may_write_p (poly_dr_p pdr)
 226 {
 227   return PDR_TYPE (pdr) == PDR_MAY_WRITE;
 228 }
 229
 230 /* POLY_BB represents a blackbox in the polyhedral model.  */
 231
 232 struct poly_bb
 233 {
 234   /* Pointer to a basic block or a statement in the compiler.  */
 235   gimple_poly_bb_p black_box;
 236
 237   /* Pointer to the SCOP containing this PBB.  */
 238   scop_p scop;
 239
 240   /* The iteration domain of this bb.  The layout of this polyhedron
 241      is I|G with I the iteration domain, G the context parameters.
 242
 243      Example:
 244
 245      for (i = a - 7*b + 8; i <= 3*a + 13*b + 20; i++)
 246        for (j = 2; j <= 2*i + 5; j++)
 247          for (k = 0; k <= 5; k++)
 248            S (i,j,k)
 249
 250      Loop iterators: i, j, k
 251      Parameters: a, b
 252
 253      | i >=  a -  7b +  8
 254      | i <= 3a + 13b + 20
 255      | j >= 2
 256      | j <= 2i + 5
 257      | k >= 0
 258      | k <= 5
 259
 260      The number of variables in the DOMAIN may change and is not
 261      related to the number of loops in the original code.  */
 262   isl_set *domain;
 263   isl_set *iterators;
 264
 265   /* The data references we access.  */
 266   vec<poly_dr_p> drs;
 267
 268   /* The last basic block generated for this pbb.  */
 269   basic_block new_bb;
 270 };
 271
 272 #define PBB_BLACK_BOX(PBB) ((gimple_poly_bb_p) PBB->black_box)
 273 #define PBB_SCOP(PBB) (PBB->scop)
 274 #define PBB_DRS(PBB) (PBB->drs)
 275
 276 extern poly_bb_p new_poly_bb (scop_p, gimple_poly_bb_p);
 277 extern void print_pbb_domain (FILE *, poly_bb_p);
 278 extern void print_pbb (FILE *, poly_bb_p);
 279 extern void print_scop_context (FILE *, scop_p);
 280 extern void print_scop (FILE *, scop_p);
 281 extern void debug_pbb_domain (poly_bb_p);
 282 extern void debug_pbb (poly_bb_p);
 283 extern void print_pdrs (FILE *, poly_bb_p);
 284 extern void debug_pdrs (poly_bb_p);
 285 extern void debug_scop_context (scop_p);
 286 extern void debug_scop (scop_p);
 287 extern void print_scop_params (FILE *, scop_p);
 288 extern void debug_scop_params (scop_p);
 289 extern void print_iteration_domain (FILE *, poly_bb_p);
 290 extern void print_iteration_domains (FILE *, scop_p);
 291 extern void debug_iteration_domain (poly_bb_p);
 292 extern void debug_iteration_domains (scop_p);
 293 extern void print_isl_set (FILE *, isl_set *);
 294 extern void print_isl_map (FILE *, isl_map *);
 295 extern void print_isl_union_map (FILE *, isl_union_map *);
 296 extern void print_isl_aff (FILE *, isl_aff *);
 297 extern void print_isl_constraint (FILE *, isl_constraint *);
 298 extern void print_isl_schedule (FILE *, isl_schedule *);
 299 extern void debug_isl_schedule (isl_schedule *);
 300 extern void print_isl_ast (FILE *, isl_ast_node *);
 301 extern void debug_isl_ast (isl_ast_node *);
 302 extern void debug_isl_set (isl_set *);
 303 extern void debug_isl_map (isl_map *);
 304 extern void debug_isl_union_map (isl_union_map *);
 305 extern void debug_isl_aff (isl_aff *);
 306 extern void debug_isl_constraint (isl_constraint *);
 307 extern void debug_gmp_value (mpz_t);
 308 extern void debug_scop_pbb (scop_p scop, int i);
 309 extern void print_schedule_ast (FILE *, __isl_keep isl_schedule *, scop_p);
 310 extern void debug_schedule_ast (__isl_keep isl_schedule *, scop_p);
 311
 312 /* The basic block of the PBB.  */
 313
 314 static inline basic_block
 315 pbb_bb (poly_bb_p pbb)
 316 {
 317   return GBB_BB (PBB_BLACK_BOX (pbb));
 318 }
 319
 320 static inline int
 321 pbb_index (poly_bb_p pbb)
 322 {
 323   return pbb_bb (pbb)->index;
 324 }
 325
 326 /* The loop of the PBB.  */
 327
 328 static inline loop_p
 329 pbb_loop (poly_bb_p pbb)
 330 {
 331   return gbb_loop (PBB_BLACK_BOX (pbb));
 332 }
 333
 334 /* The scop that contains the PDR.  */
 335
 336 static inline scop_p
 337 pdr_scop (poly_dr_p pdr)
 338 {
 339   return PBB_SCOP (PDR_PBB (pdr));
 340 }
 341
 342 /* Set black box of PBB to BLACKBOX.  */
 343
 344 static inline void
 345 pbb_set_black_box (poly_bb_p pbb, gimple_poly_bb_p black_box)
 346 {
 347   pbb->black_box = black_box;
 348 }
 349
 350 /* A helper structure to keep track of data references, polyhedral BBs, and
 351    alias sets.  */
 352
 353 struct dr_info
 354 {
 355   enum {
 356     invalid_alias_set = -1
 357   };
 358   /* The data reference.  */
 359   data_reference_p dr;
 360
 361   /* The polyhedral BB containing this DR.  */
 362   poly_bb_p pbb;
 363
 364   /* ALIAS_SET is the SCC number assigned by a graph_dfs of the alias graph.
 365      -1 is an invalid alias set.  */
 366   int alias_set;
 367
 368   /* Construct a DR_INFO from a data reference DR, an ALIAS_SET, and a PBB.  */
 369   dr_info (data_reference_p dr, poly_bb_p pbb,
 370            int alias_set = invalid_alias_set)
 371     : dr (dr), pbb (pbb), alias_set (alias_set) {}
 372 };
 373
 374 /* A SCOP is a Static Control Part of the program, simple enough to be
 375    represented in polyhedral form.  */
 376 struct scop
 377 {
 378   /* A SCOP is defined as a SESE region.  */
 379   sese_info_p scop_info;
 380
 381   /* Number of parameters in SCoP.  */
 382   graphite_dim_t nb_params;
 383
 384   /* The maximum alias set as assigned to drs by build_alias_sets.  */
 385   unsigned max_alias_set;
 386
 387   /* All the basic blocks in this scop that contain memory references
 388      and that will be represented as statements in the polyhedral
 389      representation.  */
 390   vec<poly_bb_p> pbbs;
 391
 392   /* All the data references in this scop.  */
 393   vec<dr_info> drs;
 394
 395   /* The context describes known restrictions concerning the parameters
 396      and relations in between the parameters.
 397
 398   void f (int8_t a, uint_16_t b) {
 399     c = 2 a + b;
 400     ...
 401   }
 402
 403   Here we can add these restrictions to the context:
 404
 405   -128 >= a >= 127
 406      0 >= b >= 65,535
 407      c = 2a + b  */
 408   isl_set *param_context;
 409
 410   /* The context used internally by isl.  */
 411   isl_ctx *isl_context;
 412
 413   /* SCoP original schedule.  */
 414   isl_schedule *original_schedule;
 415
 416   /* SCoP transformed schedule.  */
 417   isl_schedule *transformed_schedule;
 418
 419   /* The data dependence relation among the data references in this scop.  */
 420   isl_union_map *dependence;
 421 };
 422
 423 extern scop_p new_scop (edge, edge);
 424 extern void free_scop (scop_p);
 425 extern gimple_poly_bb_p new_gimple_poly_bb (basic_block, vec<data_reference_p>,
 426                                             vec<scalar_use>, vec<tree>);
 427 extern bool apply_poly_transforms (scop_p);
 428
 429 /* Set the region of SCOP to REGION.  */
 430
 431 static inline void
 432 scop_set_region (scop_p scop, sese_info_p region)
 433 {
 434   scop->scop_info = region;
 435 }
 436
 437 /* Returns the number of parameters for SCOP.  */
 438
 439 static inline graphite_dim_t
 440 scop_nb_params (scop_p scop)
 441 {
 442   return scop->nb_params;
 443 }
 444
 445 /* Set the number of params of SCOP to NB_PARAMS.  */
 446
 447 static inline void
 448 scop_set_nb_params (scop_p scop, graphite_dim_t nb_params)
 449 {
 450   scop->nb_params = nb_params;
 451 }
 452
 453 extern void scop_get_dependences (scop_p scop);
 454
 455 bool
 456 carries_deps (__isl_keep isl_union_map *schedule,
 457               __isl_keep isl_union_map *deps,
 458               int depth);
 459
 460 extern bool build_poly_scop (scop_p);
 461 extern bool graphite_regenerate_ast_isl (scop_p);
 462 extern void build_scops (vec<scop_p> *);
 463 extern tree cached_scalar_evolution_in_region (const sese_l &, loop_p, tree);
 464 extern void dot_all_sese (FILE *, vec<sese_l> &);
 465 extern void dot_sese (sese_l &);
 466 extern void dot_cfg ();
 467
 468 #endif