gcc/tree-data-ref.h

   1 /* Data references and dependences detectors.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
   3    Free Software Foundation, Inc.
   4    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
   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 #ifndef GCC_TREE_DATA_REF_H
  23 #define GCC_TREE_DATA_REF_H
  24
  25 #include "graphds.h"
  26 #include "omega.h"
  27 #include "tree-chrec.h"
  28
  29 /*
  30   innermost_loop_behavior describes the evolution of the address of the memory
  31   reference in the innermost enclosing loop.  The address is expressed as
  32   BASE + STEP * # of iteration, and base is further decomposed as the base
  33   pointer (BASE_ADDRESS),  loop invariant offset (OFFSET) and
  34   constant offset (INIT).  Examples, in loop nest
  35
  36   for (i = 0; i < 100; i++)
  37     for (j = 3; j < 100; j++)
  38
  39                        Example 1                      Example 2
  40       data-ref         a[j].b[i][j]                   *(p + x + 16B + 4B * j)
  41
  42
  43   innermost_loop_behavior
  44       base_address     &a                             p
  45       offset           i * D_i                        x
  46       init             3 * D_j + offsetof (b)         28
  47       step             D_j                            4
  48
  49   */
  50 struct innermost_loop_behavior
  51 {
  52   tree base_address;
  53   tree offset;
  54   tree init;
  55   tree step;
  56
  57   /* Alignment information.  ALIGNED_TO is set to the largest power of two
  58      that divides OFFSET.  */
  59   tree aligned_to;
  60 };
  61
  62 /* Describes the evolutions of indices of the memory reference.  The indices
  63    are indices of the ARRAY_REFs, indexes in artificial dimensions
  64    added for member selection of records and the operands of MEM_REFs.
  65    BASE_OBJECT is the part of the reference that is loop-invariant
  66    (note that this reference does not have to cover the whole object
  67    being accessed, in which case UNCONSTRAINED_BASE is set; hence it is
  68    not recommended to use BASE_OBJECT in any code generation).
  69    For the examples above,
  70
  71    base_object:        a                              *(p + x + 4B * j_0)
  72    indices:            {j_0, +, 1}_2                  {16, +, 4}_2
  73                        4
  74                        {i_0, +, 1}_1
  75                        {j_0, +, 1}_2
  76 */
  77
  78 struct indices
  79 {
  80   /* The object.  */
  81   tree base_object;
  82
  83   /* A list of chrecs.  Access functions of the indices.  */
  84   VEC(tree,heap) *access_fns;
  85
  86   /* Whether BASE_OBJECT is an access representing the whole object
  87      or whether the access could not be constrained.  */
  88   bool unconstrained_base;
  89 };
  90
  91 struct dr_alias
  92 {
  93   /* The alias information that should be used for new pointers to this
  94      location.  */
  95   struct ptr_info_def *ptr_info;
  96 };
  97
  98 /* An integer vector.  A vector formally consists of an element of a vector
  99    space. A vector space is a set that is closed under vector addition
 100    and scalar multiplication.  In this vector space, an element is a list of
 101    integers.  */
 102 typedef int *lambda_vector;
 103 DEF_VEC_P(lambda_vector);
 104 DEF_VEC_ALLOC_P(lambda_vector,heap);
 105 DEF_VEC_ALLOC_P(lambda_vector,gc);
 106
 107 /* An integer matrix.  A matrix consists of m vectors of length n (IE
 108    all vectors are the same length).  */
 109 typedef lambda_vector *lambda_matrix;
 110
 111 /* Each vector of the access matrix represents a linear access
 112    function for a subscript.  First elements correspond to the
 113    leftmost indices, ie. for a[i][j] the first vector corresponds to
 114    the subscript in "i".  The elements of a vector are relative to
 115    the loop nests in which the data reference is considered,
 116    i.e. the vector is relative to the SCoP that provides the context
 117    in which this data reference occurs.
 118
 119    For example, in
 120
 121    | loop_1
 122    |    loop_2
 123    |      a[i+3][2*j+n-1]
 124
 125    if "i" varies in loop_1 and "j" varies in loop_2, the access
 126    matrix with respect to the loop nest {loop_1, loop_2} is:
 127
 128    | loop_1  loop_2  param_n  cst
 129    |   1       0        0      3
 130    |   0       2        1     -1
 131
 132    whereas the access matrix with respect to loop_2 considers "i" as
 133    a parameter:
 134
 135    | loop_2  param_i  param_n  cst
 136    |   0       1         0      3
 137    |   2       0         1     -1
 138 */
 139 struct access_matrix
 140 {
 141   VEC (loop_p, heap) *loop_nest;
 142   int nb_induction_vars;
 143   VEC (tree, heap) *parameters;
 144   VEC (lambda_vector, gc) *matrix;
 145 };
 146
 147 #define AM_LOOP_NEST(M) (M)->loop_nest
 148 #define AM_NB_INDUCTION_VARS(M) (M)->nb_induction_vars
 149 #define AM_PARAMETERS(M) (M)->parameters
 150 #define AM_MATRIX(M) (M)->matrix
 151 #define AM_NB_PARAMETERS(M) (VEC_length (tree, AM_PARAMETERS(M)))
 152 #define AM_CONST_COLUMN_INDEX(M) (AM_NB_INDUCTION_VARS (M) + AM_NB_PARAMETERS (M))
 153 #define AM_NB_COLUMNS(M) (AM_NB_INDUCTION_VARS (M) + AM_NB_PARAMETERS (M) + 1)
 154 #define AM_GET_SUBSCRIPT_ACCESS_VECTOR(M, I) VEC_index (lambda_vector, AM_MATRIX (M), I)
 155 #define AM_GET_ACCESS_MATRIX_ELEMENT(M, I, J) AM_GET_SUBSCRIPT_ACCESS_VECTOR (M, I)[J]
 156
 157 /* Return the column in the access matrix of LOOP_NUM.  */
 158
 159 static inline int
 160 am_vector_index_for_loop (struct access_matrix *access_matrix, int loop_num)
 161 {
 162   int i;
 163   loop_p l;
 164
 165   for (i = 0; VEC_iterate (loop_p, AM_LOOP_NEST (access_matrix), i, l); i++)
 166     if (l->num == loop_num)
 167       return i;
 168
 169   gcc_unreachable();
 170 }
 171
 172 struct data_reference
 173 {
 174   /* A pointer to the statement that contains this DR.  */
 175   gimple stmt;
 176
 177   /* A pointer to the memory reference.  */
 178   tree ref;
 179
 180   /* Auxiliary info specific to a pass.  */
 181   void *aux;
 182
 183   /* True when the data reference is in RHS of a stmt.  */
 184   bool is_read;
 185
 186   /* Behavior of the memory reference in the innermost loop.  */
 187   struct innermost_loop_behavior innermost;
 188
 189   /* Subscripts of this data reference.  */
 190   struct indices indices;
 191
 192   /* Alias information for the data reference.  */
 193   struct dr_alias alias;
 194
 195   /* Matrix representation for the data access functions.  */
 196   struct access_matrix *access_matrix;
 197 };
 198
 199 #define DR_STMT(DR)                (DR)->stmt
 200 #define DR_REF(DR)                 (DR)->ref
 201 #define DR_BASE_OBJECT(DR)         (DR)->indices.base_object
 202 #define DR_UNCONSTRAINED_BASE(DR)  (DR)->indices.unconstrained_base
 203 #define DR_ACCESS_FNS(DR)          (DR)->indices.access_fns
 204 #define DR_ACCESS_FN(DR, I)        VEC_index (tree, DR_ACCESS_FNS (DR), I)
 205 #define DR_NUM_DIMENSIONS(DR)      VEC_length (tree, DR_ACCESS_FNS (DR))
 206 #define DR_IS_READ(DR)             (DR)->is_read
 207 #define DR_IS_WRITE(DR)            (!DR_IS_READ (DR))
 208 #define DR_BASE_ADDRESS(DR)        (DR)->innermost.base_address
 209 #define DR_OFFSET(DR)              (DR)->innermost.offset
 210 #define DR_INIT(DR)                (DR)->innermost.init
 211 #define DR_STEP(DR)                (DR)->innermost.step
 212 #define DR_PTR_INFO(DR)            (DR)->alias.ptr_info
 213 #define DR_ALIGNED_TO(DR)          (DR)->innermost.aligned_to
 214 #define DR_ACCESS_MATRIX(DR)       (DR)->access_matrix
 215
 216 typedef struct data_reference *data_reference_p;
 217 DEF_VEC_P(data_reference_p);
 218 DEF_VEC_ALLOC_P (data_reference_p, heap);
 219
 220 enum data_dependence_direction {
 221   dir_positive,
 222   dir_negative,
 223   dir_equal,
 224   dir_positive_or_negative,
 225   dir_positive_or_equal,
 226   dir_negative_or_equal,
 227   dir_star,
 228   dir_independent
 229 };
 230
 231 /* The description of the grid of iterations that overlap.  At most
 232    two loops are considered at the same time just now, hence at most
 233    two functions are needed.  For each of the functions, we store
 234    the vector of coefficients, f[0] + x * f[1] + y * f[2] + ...,
 235    where x, y, ... are variables.  */
 236
 237 #define MAX_DIM 2
 238
 239 /* Special values of N.  */
 240 #define NO_DEPENDENCE 0
 241 #define NOT_KNOWN (MAX_DIM + 1)
 242 #define CF_NONTRIVIAL_P(CF) ((CF)->n != NO_DEPENDENCE && (CF)->n != NOT_KNOWN)
 243 #define CF_NOT_KNOWN_P(CF) ((CF)->n == NOT_KNOWN)
 244 #define CF_NO_DEPENDENCE_P(CF) ((CF)->n == NO_DEPENDENCE)
 245
 246 typedef VEC (tree, heap) *affine_fn;
 247
 248 typedef struct
 249 {
 250   unsigned n;
 251   affine_fn fns[MAX_DIM];
 252 } conflict_function;
 253
 254 /* What is a subscript?  Given two array accesses a subscript is the
 255    tuple composed of the access functions for a given dimension.
 256    Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
 257    subscripts: (f1, g1), (f2, g2), (f3, g3).  These three subscripts
 258    are stored in the data_dependence_relation structure under the form
 259    of an array of subscripts.  */
 260
 261 struct subscript
 262 {
 263   /* A description of the iterations for which the elements are
 264      accessed twice.  */
 265   conflict_function *conflicting_iterations_in_a;
 266   conflict_function *conflicting_iterations_in_b;
 267
 268   /* This field stores the information about the iteration domain
 269      validity of the dependence relation.  */
 270   tree last_conflict;
 271
 272   /* Distance from the iteration that access a conflicting element in
 273      A to the iteration that access this same conflicting element in
 274      B.  The distance is a tree scalar expression, i.e. a constant or a
 275      symbolic expression, but certainly not a chrec function.  */
 276   tree distance;
 277 };
 278
 279 typedef struct subscript *subscript_p;
 280 DEF_VEC_P(subscript_p);
 281 DEF_VEC_ALLOC_P (subscript_p, heap);
 282
 283 #define SUB_CONFLICTS_IN_A(SUB) SUB->conflicting_iterations_in_a
 284 #define SUB_CONFLICTS_IN_B(SUB) SUB->conflicting_iterations_in_b
 285 #define SUB_LAST_CONFLICT(SUB) SUB->last_conflict
 286 #define SUB_DISTANCE(SUB) SUB->distance
 287
 288 /* A data_dependence_relation represents a relation between two
 289    data_references A and B.  */
 290
 291 struct data_dependence_relation
 292 {
 293
 294   struct data_reference *a;
 295   struct data_reference *b;
 296
 297   /* A "yes/no/maybe" field for the dependence relation:
 298
 299      - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
 300        relation between A and B, and the description of this relation
 301        is given in the SUBSCRIPTS array,
 302
 303      - when "ARE_DEPENDENT == chrec_known", there is no dependence and
 304        SUBSCRIPTS is empty,
 305
 306      - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
 307        but the analyzer cannot be more specific.  */
 308   tree are_dependent;
 309
 310   /* For each subscript in the dependence test, there is an element in
 311      this array.  This is the attribute that labels the edge A->B of
 312      the data_dependence_relation.  */
 313   VEC (subscript_p, heap) *subscripts;
 314
 315   /* The analyzed loop nest.  */
 316   VEC (loop_p, heap) *loop_nest;
 317
 318   /* The classic direction vector.  */
 319   VEC (lambda_vector, heap) *dir_vects;
 320
 321   /* The classic distance vector.  */
 322   VEC (lambda_vector, heap) *dist_vects;
 323
 324   /* An index in loop_nest for the innermost loop that varies for
 325      this data dependence relation.  */
 326   unsigned inner_loop;
 327
 328   /* Is the dependence reversed with respect to the lexicographic order?  */
 329   bool reversed_p;
 330
 331   /* When the dependence relation is affine, it can be represented by
 332      a distance vector.  */
 333   bool affine_p;
 334
 335   /* Set to true when the dependence relation is on the same data
 336      access.  */
 337   bool self_reference_p;
 338 };
 339
 340 typedef struct data_dependence_relation *ddr_p;
 341 DEF_VEC_P(ddr_p);
 342 DEF_VEC_ALLOC_P(ddr_p,heap);
 343
 344 #define DDR_A(DDR) DDR->a
 345 #define DDR_B(DDR) DDR->b
 346 #define DDR_AFFINE_P(DDR) DDR->affine_p
 347 #define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent
 348 #define DDR_SUBSCRIPTS(DDR) DDR->subscripts
 349 #define DDR_SUBSCRIPT(DDR, I) VEC_index (subscript_p, DDR_SUBSCRIPTS (DDR), I)
 350 #define DDR_NUM_SUBSCRIPTS(DDR) VEC_length (subscript_p, DDR_SUBSCRIPTS (DDR))
 351
 352 #define DDR_LOOP_NEST(DDR) DDR->loop_nest
 353 /* The size of the direction/distance vectors: the number of loops in
 354    the loop nest.  */
 355 #define DDR_NB_LOOPS(DDR) (VEC_length (loop_p, DDR_LOOP_NEST (DDR)))
 356 #define DDR_INNER_LOOP(DDR) DDR->inner_loop
 357 #define DDR_SELF_REFERENCE(DDR) DDR->self_reference_p
 358
 359 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
 360 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
 361 #define DDR_NUM_DIST_VECTS(DDR) \
 362   (VEC_length (lambda_vector, DDR_DIST_VECTS (DDR)))
 363 #define DDR_NUM_DIR_VECTS(DDR) \
 364   (VEC_length (lambda_vector, DDR_DIR_VECTS (DDR)))
 365 #define DDR_DIR_VECT(DDR, I) \
 366   VEC_index (lambda_vector, DDR_DIR_VECTS (DDR), I)
 367 #define DDR_DIST_VECT(DDR, I) \
 368   VEC_index (lambda_vector, DDR_DIST_VECTS (DDR), I)
 369 #define DDR_REVERSED_P(DDR) DDR->reversed_p
 370
 371 \f
 372 bool dr_analyze_innermost (struct data_reference *, struct loop *);
 373 extern bool compute_data_dependences_for_loop (struct loop *, bool,
 374                                                VEC (loop_p, heap) **,
 375                                                VEC (data_reference_p, heap) **,
 376                                                VEC (ddr_p, heap) **);
 377 extern bool compute_data_dependences_for_bb (basic_block, bool,
 378                                              VEC (data_reference_p, heap) **,
 379                                              VEC (ddr_p, heap) **);
 380 extern void debug_ddrs (VEC (ddr_p, heap) *);
 381 extern void dump_data_reference (FILE *, struct data_reference *);
 382 extern void debug_data_reference (struct data_reference *);
 383 extern void debug_data_references (VEC (data_reference_p, heap) *);
 384 extern void debug_data_dependence_relation (struct data_dependence_relation *);
 385 extern void dump_data_dependence_relations (FILE *, VEC (ddr_p, heap) *);
 386 extern void debug_data_dependence_relations (VEC (ddr_p, heap) *);
 387 extern void free_dependence_relation (struct data_dependence_relation *);
 388 extern void free_dependence_relations (VEC (ddr_p, heap) *);
 389 extern void free_data_ref (data_reference_p);
 390 extern void free_data_refs (VEC (data_reference_p, heap) *);
 391 extern bool find_data_references_in_stmt (struct loop *, gimple,
 392                                           VEC (data_reference_p, heap) **);
 393 extern bool graphite_find_data_references_in_stmt (loop_p, loop_p, gimple,
 394                                                    VEC (data_reference_p, heap) **);
 395 struct data_reference *create_data_ref (loop_p, loop_p, tree, gimple, bool);
 396 extern bool find_loop_nest (struct loop *, VEC (loop_p, heap) **);
 397 extern struct data_dependence_relation *initialize_data_dependence_relation
 398      (struct data_reference *, struct data_reference *, VEC (loop_p, heap) *);
 399 extern void compute_self_dependence (struct data_dependence_relation *);
 400 extern bool compute_all_dependences (VEC (data_reference_p, heap) *,
 401                                      VEC (ddr_p, heap) **, VEC (loop_p, heap) *,
 402                                      bool);
 403 extern tree find_data_references_in_bb (struct loop *, basic_block,
 404                                         VEC (data_reference_p, heap) **);
 405
 406 extern bool dr_may_alias_p (const struct data_reference *,
 407                             const struct data_reference *, bool);
 408 extern bool dr_equal_offsets_p (struct data_reference *,
 409                                 struct data_reference *);
 410
 411
 412 /* Return true when the base objects of data references A and B are
 413    the same memory object.  */
 414
 415 static inline bool
 416 same_data_refs_base_objects (data_reference_p a, data_reference_p b)
 417 {
 418   return DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b)
 419     && operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0);
 420 }
 421
 422 /* Return true when the data references A and B are accessing the same
 423    memory object with the same access functions.  */
 424
 425 static inline bool
 426 same_data_refs (data_reference_p a, data_reference_p b)
 427 {
 428   unsigned int i;
 429
 430   /* The references are exactly the same.  */
 431   if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
 432     return true;
 433
 434   if (!same_data_refs_base_objects (a, b))
 435     return false;
 436
 437   for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
 438     if (!eq_evolutions_p (DR_ACCESS_FN (a, i), DR_ACCESS_FN (b, i)))
 439       return false;
 440
 441   return true;
 442 }
 443
 444 /* Return true when the DDR contains two data references that have the
 445    same access functions.  */
 446
 447 static inline bool
 448 same_access_functions (const struct data_dependence_relation *ddr)
 449 {
 450   unsigned i;
 451
 452   for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
 453     if (!eq_evolutions_p (DR_ACCESS_FN (DDR_A (ddr), i),
 454                           DR_ACCESS_FN (DDR_B (ddr), i)))
 455       return false;
 456
 457   return true;
 458 }
 459
 460 /* Return true when DDR is an anti-dependence relation.  */
 461
 462 static inline bool
 463 ddr_is_anti_dependent (ddr_p ddr)
 464 {
 465   return (DDR_ARE_DEPENDENT (ddr) == NULL_TREE
 466           && DR_IS_READ (DDR_A (ddr))
 467           && DR_IS_WRITE (DDR_B (ddr))
 468           && !same_access_functions (ddr));
 469 }
 470
 471 /* Return true when DEPENDENCE_RELATIONS contains an anti-dependence.  */
 472
 473 static inline bool
 474 ddrs_have_anti_deps (VEC (ddr_p, heap) *dependence_relations)
 475 {
 476   unsigned i;
 477   ddr_p ddr;
 478
 479   for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
 480     if (ddr_is_anti_dependent (ddr))
 481       return true;
 482
 483   return false;
 484 }
 485
 486 /* Returns the dependence level for a vector DIST of size LENGTH.
 487    LEVEL = 0 means a lexicographic dependence, i.e. a dependence due
 488    to the sequence of statements, not carried by any loop.  */
 489
 490 static inline unsigned
 491 dependence_level (lambda_vector dist_vect, int length)
 492 {
 493   int i;
 494
 495   for (i = 0; i < length; i++)
 496     if (dist_vect[i] != 0)
 497       return i + 1;
 498
 499   return 0;
 500 }
 501
 502 /* Return the dependence level for the DDR relation.  */
 503
 504 static inline unsigned
 505 ddr_dependence_level (ddr_p ddr)
 506 {
 507   unsigned vector;
 508   unsigned level = 0;
 509
 510   if (DDR_DIST_VECTS (ddr))
 511     level = dependence_level (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr));
 512
 513   for (vector = 1; vector < DDR_NUM_DIST_VECTS (ddr); vector++)
 514     level = MIN (level, dependence_level (DDR_DIST_VECT (ddr, vector),
 515                                           DDR_NB_LOOPS (ddr)));
 516   return level;
 517 }
 518
 519 \f
 520
 521 /* A Reduced Dependence Graph (RDG) vertex representing a statement.  */
 522 typedef struct rdg_vertex
 523 {
 524   /* The statement represented by this vertex.  */
 525   gimple stmt;
 526
 527   /* Vector of data-references in this statement.  */
 528   VEC(data_reference_p, heap) *datarefs;
 529
 530   /* True when the statement contains a write to memory.  */
 531   bool has_mem_write;
 532
 533   /* True when the statement contains a read from memory.  */
 534   bool has_mem_reads;
 535 } *rdg_vertex_p;
 536
 537 #define RDGV_STMT(V)     ((struct rdg_vertex *) ((V)->data))->stmt
 538 #define RDGV_DATAREFS(V) ((struct rdg_vertex *) ((V)->data))->datarefs
 539 #define RDGV_HAS_MEM_WRITE(V) ((struct rdg_vertex *) ((V)->data))->has_mem_write
 540 #define RDGV_HAS_MEM_READS(V) ((struct rdg_vertex *) ((V)->data))->has_mem_reads
 541 #define RDG_STMT(RDG, I) RDGV_STMT (&(RDG->vertices[I]))
 542 #define RDG_DATAREFS(RDG, I) RDGV_DATAREFS (&(RDG->vertices[I]))
 543 #define RDG_MEM_WRITE_STMT(RDG, I) RDGV_HAS_MEM_WRITE (&(RDG->vertices[I]))
 544 #define RDG_MEM_READS_STMT(RDG, I) RDGV_HAS_MEM_READS (&(RDG->vertices[I]))
 545
 546 void debug_rdg_vertex (struct graph *, int);
 547 void debug_rdg_component (struct graph *, int);
 548 void dump_rdg (FILE *, struct graph *);
 549 void debug_rdg (struct graph *);
 550 int rdg_vertex_for_stmt (struct graph *, gimple);
 551
 552 /* Data dependence type.  */
 553
 554 enum rdg_dep_type
 555 {
 556   /* Read After Write (RAW).  */
 557   flow_dd = 'f',
 558
 559   /* Write After Read (WAR).  */
 560   anti_dd = 'a',
 561
 562   /* Write After Write (WAW).  */
 563   output_dd = 'o',
 564
 565   /* Read After Read (RAR).  */
 566   input_dd = 'i'
 567 };
 568
 569 /* Dependence information attached to an edge of the RDG.  */
 570
 571 typedef struct rdg_edge
 572 {
 573   /* Type of the dependence.  */
 574   enum rdg_dep_type type;
 575
 576   /* Levels of the dependence: the depth of the loops that carry the
 577      dependence.  */
 578   unsigned level;
 579
 580   /* Dependence relation between data dependences, NULL when one of
 581      the vertices is a scalar.  */
 582   ddr_p relation;
 583 } *rdg_edge_p;
 584
 585 #define RDGE_TYPE(E)        ((struct rdg_edge *) ((E)->data))->type
 586 #define RDGE_LEVEL(E)       ((struct rdg_edge *) ((E)->data))->level
 587 #define RDGE_RELATION(E)    ((struct rdg_edge *) ((E)->data))->relation
 588
 589 struct graph *build_rdg (struct loop *,
 590                          VEC (loop_p, heap) **,
 591                          VEC (ddr_p, heap) **,
 592                          VEC (data_reference_p, heap) **);
 593 struct graph *build_empty_rdg (int);
 594 void free_rdg (struct graph *);
 595
 596 /* Return the index of the variable VAR in the LOOP_NEST array.  */
 597
 598 static inline int
 599 index_in_loop_nest (int var, VEC (loop_p, heap) *loop_nest)
 600 {
 601   struct loop *loopi;
 602   int var_index;
 603
 604   for (var_index = 0; VEC_iterate (loop_p, loop_nest, var_index, loopi);
 605        var_index++)
 606     if (loopi->num == var)
 607       break;
 608
 609   return var_index;
 610 }
 611
 612 bool rdg_defs_used_in_other_loops_p (struct graph *, int);
 613
 614 /* Returns true when the data reference DR the form "A[i] = ..."
 615    with a stride equal to its unit type size.  */
 616
 617 static inline bool
 618 adjacent_dr_p (struct data_reference *dr)
 619 {
 620   /* If this is a bitfield store bail out.  */
 621   if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF
 622       && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1)))
 623     return false;
 624
 625   if (!DR_STEP (dr)
 626       || TREE_CODE (DR_STEP (dr)) != INTEGER_CST)
 627     return false;
 628
 629   return tree_int_cst_equal (fold_unary (ABS_EXPR, TREE_TYPE (DR_STEP (dr)),
 630                                          DR_STEP (dr)),
 631                              TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
 632 }
 633
 634 /* In tree-data-ref.c  */
 635 void split_constant_offset (tree , tree *, tree *);
 636
 637 /* Strongly connected components of the reduced data dependence graph.  */
 638
 639 typedef struct rdg_component
 640 {
 641   int num;
 642   VEC (int, heap) *vertices;
 643 } *rdgc;
 644
 645 DEF_VEC_P (rdgc);
 646 DEF_VEC_ALLOC_P (rdgc, heap);
 647
 648 DEF_VEC_P (bitmap);
 649 DEF_VEC_ALLOC_P (bitmap, heap);
 650
 651 /* Compute the greatest common divisor of a VECTOR of SIZE numbers.  */
 652
 653 static inline int
 654 lambda_vector_gcd (lambda_vector vector, int size)
 655 {
 656   int i;
 657   int gcd1 = 0;
 658
 659   if (size > 0)
 660     {
 661       gcd1 = vector[0];
 662       for (i = 1; i < size; i++)
 663         gcd1 = gcd (gcd1, vector[i]);
 664     }
 665   return gcd1;
 666 }
 667
 668 /* Allocate a new vector of given SIZE.  */
 669
 670 static inline lambda_vector
 671 lambda_vector_new (int size)
 672 {
 673   return (lambda_vector) ggc_alloc_cleared_atomic (sizeof (int) * size);
 674 }
 675
 676 /* Clear out vector VEC1 of length SIZE.  */
 677
 678 static inline void
 679 lambda_vector_clear (lambda_vector vec1, int size)
 680 {
 681   memset (vec1, 0, size * sizeof (*vec1));
 682 }
 683
 684 /* Returns true when the vector V is lexicographically positive, in
 685    other words, when the first nonzero element is positive.  */
 686
 687 static inline bool
 688 lambda_vector_lexico_pos (lambda_vector v,
 689                           unsigned n)
 690 {
 691   unsigned i;
 692   for (i = 0; i < n; i++)
 693     {
 694       if (v[i] == 0)
 695         continue;
 696       if (v[i] < 0)
 697         return false;
 698       if (v[i] > 0)
 699         return true;
 700     }
 701   return true;
 702 }
 703
 704 /* Return true if vector VEC1 of length SIZE is the zero vector.  */
 705
 706 static inline bool
 707 lambda_vector_zerop (lambda_vector vec1, int size)
 708 {
 709   int i;
 710   for (i = 0; i < size; i++)
 711     if (vec1[i] != 0)
 712       return false;
 713   return true;
 714 }
 715
 716 /* Allocate a matrix of M rows x  N cols.  */
 717
 718 static inline lambda_matrix
 719 lambda_matrix_new (int m, int n, struct obstack *lambda_obstack)
 720 {
 721   lambda_matrix mat;
 722   int i;
 723
 724   mat = (lambda_matrix) obstack_alloc (lambda_obstack,
 725                                        sizeof (lambda_vector *) * m);
 726
 727   for (i = 0; i < m; i++)
 728     mat[i] = lambda_vector_new (n);
 729
 730   return mat;
 731 }
 732
 733 #endif  /* GCC_TREE_DATA_REF_H  */