gcc/tree-data-ref.h

   1 /* Data references and dependences detectors.
   2    Copyright (C) 2003-2019 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <pop@cri.ensmp.fr>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_TREE_DATA_REF_H
  22 #define GCC_TREE_DATA_REF_H
  23
  24 #include "graphds.h"
  25 #include "tree-chrec.h"
  26 #include "opt-problem.h"
  27
  28 /*
  29   innermost_loop_behavior describes the evolution of the address of the memory
  30   reference in the innermost enclosing loop.  The address is expressed as
  31   BASE + STEP * # of iteration, and base is further decomposed as the base
  32   pointer (BASE_ADDRESS),  loop invariant offset (OFFSET) and
  33   constant offset (INIT).  Examples, in loop nest
  34
  35   for (i = 0; i < 100; i++)
  36     for (j = 3; j < 100; j++)
  37
  38                        Example 1                      Example 2
  39       data-ref         a[j].b[i][j]                   *(p + x + 16B + 4B * j)
  40
  41
  42   innermost_loop_behavior
  43       base_address     &a                             p
  44       offset           i * D_i                        x
  45       init             3 * D_j + offsetof (b)         28
  46       step             D_j                            4
  47
  48   */
  49 struct innermost_loop_behavior
  50 {
  51   tree base_address;
  52   tree offset;
  53   tree init;
  54   tree step;
  55
  56   /* BASE_ADDRESS is known to be misaligned by BASE_MISALIGNMENT bytes
  57      from an alignment boundary of BASE_ALIGNMENT bytes.  For example,
  58      if we had:
  59
  60        struct S __attribute__((aligned(16))) { ... };
  61
  62        char *ptr;
  63        ... *(struct S *) (ptr - 4) ...;
  64
  65      the information would be:
  66
  67        base_address:      ptr
  68        base_aligment:      16
  69        base_misalignment:   4
  70        init:               -4
  71
  72      where init cancels the base misalignment.  If instead we had a
  73      reference to a particular field:
  74
  75        struct S __attribute__((aligned(16))) { ... int f; ... };
  76
  77        char *ptr;
  78        ... ((struct S *) (ptr - 4))->f ...;
  79
  80      the information would be:
  81
  82        base_address:      ptr
  83        base_aligment:      16
  84        base_misalignment:   4
  85        init:               -4 + offsetof (S, f)
  86
  87      where base_address + init might also be misaligned, and by a different
  88      amount from base_address.  */
  89   unsigned int base_alignment;
  90   unsigned int base_misalignment;
  91
  92   /* The largest power of two that divides OFFSET, capped to a suitably
  93      high value if the offset is zero.  This is a byte rather than a bit
  94      quantity.  */
  95   unsigned int offset_alignment;
  96
  97   /* Likewise for STEP.  */
  98   unsigned int step_alignment;
  99 };
 100
 101 /* Describes the evolutions of indices of the memory reference.  The indices
 102    are indices of the ARRAY_REFs, indexes in artificial dimensions
 103    added for member selection of records and the operands of MEM_REFs.
 104    BASE_OBJECT is the part of the reference that is loop-invariant
 105    (note that this reference does not have to cover the whole object
 106    being accessed, in which case UNCONSTRAINED_BASE is set; hence it is
 107    not recommended to use BASE_OBJECT in any code generation).
 108    For the examples above,
 109
 110    base_object:        a                              *(p + x + 4B * j_0)
 111    indices:            {j_0, +, 1}_2                  {16, +, 4}_2
 112                        4
 113                        {i_0, +, 1}_1
 114                        {j_0, +, 1}_2
 115 */
 116
 117 struct indices
 118 {
 119   /* The object.  */
 120   tree base_object;
 121
 122   /* A list of chrecs.  Access functions of the indices.  */
 123   vec<tree> access_fns;
 124
 125   /* Whether BASE_OBJECT is an access representing the whole object
 126      or whether the access could not be constrained.  */
 127   bool unconstrained_base;
 128 };
 129
 130 struct dr_alias
 131 {
 132   /* The alias information that should be used for new pointers to this
 133      location.  */
 134   struct ptr_info_def *ptr_info;
 135 };
 136
 137 /* An integer vector.  A vector formally consists of an element of a vector
 138    space. A vector space is a set that is closed under vector addition
 139    and scalar multiplication.  In this vector space, an element is a list of
 140    integers.  */
 141 typedef HOST_WIDE_INT lambda_int;
 142 typedef lambda_int *lambda_vector;
 143
 144 /* An integer matrix.  A matrix consists of m vectors of length n (IE
 145    all vectors are the same length).  */
 146 typedef lambda_vector *lambda_matrix;
 147
 148
 149
 150 struct data_reference
 151 {
 152   /* A pointer to the statement that contains this DR.  */
 153   gimple *stmt;
 154
 155   /* A pointer to the memory reference.  */
 156   tree ref;
 157
 158   /* Auxiliary info specific to a pass.  */
 159   void *aux;
 160
 161   /* True when the data reference is in RHS of a stmt.  */
 162   bool is_read;
 163
 164   /* True when the data reference is conditional within STMT,
 165      i.e. if it might not occur even when the statement is executed
 166      and runs to completion.  */
 167   bool is_conditional_in_stmt;
 168
 169   /* Behavior of the memory reference in the innermost loop.  */
 170   struct innermost_loop_behavior innermost;
 171
 172   /* Subscripts of this data reference.  */
 173   struct indices indices;
 174
 175   /* Alias information for the data reference.  */
 176   struct dr_alias alias;
 177 };
 178
 179 #define DR_STMT(DR)                (DR)->stmt
 180 #define DR_REF(DR)                 (DR)->ref
 181 #define DR_BASE_OBJECT(DR)         (DR)->indices.base_object
 182 #define DR_UNCONSTRAINED_BASE(DR)  (DR)->indices.unconstrained_base
 183 #define DR_ACCESS_FNS(DR)          (DR)->indices.access_fns
 184 #define DR_ACCESS_FN(DR, I)        DR_ACCESS_FNS (DR)[I]
 185 #define DR_NUM_DIMENSIONS(DR)      DR_ACCESS_FNS (DR).length ()
 186 #define DR_IS_READ(DR)             (DR)->is_read
 187 #define DR_IS_WRITE(DR)            (!DR_IS_READ (DR))
 188 #define DR_IS_CONDITIONAL_IN_STMT(DR) (DR)->is_conditional_in_stmt
 189 #define DR_BASE_ADDRESS(DR)        (DR)->innermost.base_address
 190 #define DR_OFFSET(DR)              (DR)->innermost.offset
 191 #define DR_INIT(DR)                (DR)->innermost.init
 192 #define DR_STEP(DR)                (DR)->innermost.step
 193 #define DR_PTR_INFO(DR)            (DR)->alias.ptr_info
 194 #define DR_BASE_ALIGNMENT(DR)      (DR)->innermost.base_alignment
 195 #define DR_BASE_MISALIGNMENT(DR)   (DR)->innermost.base_misalignment
 196 #define DR_OFFSET_ALIGNMENT(DR)    (DR)->innermost.offset_alignment
 197 #define DR_STEP_ALIGNMENT(DR)      (DR)->innermost.step_alignment
 198 #define DR_INNERMOST(DR)           (DR)->innermost
 199
 200 typedef struct data_reference *data_reference_p;
 201
 202 /* This struct is used to store the information of a data reference,
 203    including the data ref itself and the segment length for aliasing
 204    checks.  This is used to merge alias checks.  */
 205
 206 class dr_with_seg_len
 207 {
 208 public:
 209   dr_with_seg_len (data_reference_p d, tree len, unsigned HOST_WIDE_INT size,
 210                    unsigned int a)
 211     : dr (d), seg_len (len), access_size (size), align (a) {}
 212
 213   data_reference_p dr;
 214   /* The offset of the last access that needs to be checked minus
 215      the offset of the first.  */
 216   tree seg_len;
 217   /* A value that, when added to abs (SEG_LEN), gives the total number of
 218      bytes in the segment.  */
 219   poly_uint64 access_size;
 220   /* The minimum common alignment of DR's start address, SEG_LEN and
 221      ACCESS_SIZE.  */
 222   unsigned int align;
 223 };
 224
 225 /* This struct contains two dr_with_seg_len objects with aliasing data
 226    refs.  Two comparisons are generated from them.  */
 227
 228 class dr_with_seg_len_pair_t
 229 {
 230 public:
 231   dr_with_seg_len_pair_t (const dr_with_seg_len& d1,
 232                                const dr_with_seg_len& d2)
 233     : first (d1), second (d2) {}
 234
 235   dr_with_seg_len first;
 236   dr_with_seg_len second;
 237 };
 238
 239 enum data_dependence_direction {
 240   dir_positive,
 241   dir_negative,
 242   dir_equal,
 243   dir_positive_or_negative,
 244   dir_positive_or_equal,
 245   dir_negative_or_equal,
 246   dir_star,
 247   dir_independent
 248 };
 249
 250 /* The description of the grid of iterations that overlap.  At most
 251    two loops are considered at the same time just now, hence at most
 252    two functions are needed.  For each of the functions, we store
 253    the vector of coefficients, f[0] + x * f[1] + y * f[2] + ...,
 254    where x, y, ... are variables.  */
 255
 256 #define MAX_DIM 2
 257
 258 /* Special values of N.  */
 259 #define NO_DEPENDENCE 0
 260 #define NOT_KNOWN (MAX_DIM + 1)
 261 #define CF_NONTRIVIAL_P(CF) ((CF)->n != NO_DEPENDENCE && (CF)->n != NOT_KNOWN)
 262 #define CF_NOT_KNOWN_P(CF) ((CF)->n == NOT_KNOWN)
 263 #define CF_NO_DEPENDENCE_P(CF) ((CF)->n == NO_DEPENDENCE)
 264
 265 typedef vec<tree> affine_fn;
 266
 267 struct conflict_function
 268 {
 269   unsigned n;
 270   affine_fn fns[MAX_DIM];
 271 };
 272
 273 /* What is a subscript?  Given two array accesses a subscript is the
 274    tuple composed of the access functions for a given dimension.
 275    Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
 276    subscripts: (f1, g1), (f2, g2), (f3, g3).  These three subscripts
 277    are stored in the data_dependence_relation structure under the form
 278    of an array of subscripts.  */
 279
 280 struct subscript
 281 {
 282   /* The access functions of the two references.  */
 283   tree access_fn[2];
 284
 285   /* A description of the iterations for which the elements are
 286      accessed twice.  */
 287   conflict_function *conflicting_iterations_in_a;
 288   conflict_function *conflicting_iterations_in_b;
 289
 290   /* This field stores the information about the iteration domain
 291      validity of the dependence relation.  */
 292   tree last_conflict;
 293
 294   /* Distance from the iteration that access a conflicting element in
 295      A to the iteration that access this same conflicting element in
 296      B.  The distance is a tree scalar expression, i.e. a constant or a
 297      symbolic expression, but certainly not a chrec function.  */
 298   tree distance;
 299 };
 300
 301 typedef struct subscript *subscript_p;
 302
 303 #define SUB_ACCESS_FN(SUB, I) (SUB)->access_fn[I]
 304 #define SUB_CONFLICTS_IN_A(SUB) (SUB)->conflicting_iterations_in_a
 305 #define SUB_CONFLICTS_IN_B(SUB) (SUB)->conflicting_iterations_in_b
 306 #define SUB_LAST_CONFLICT(SUB) (SUB)->last_conflict
 307 #define SUB_DISTANCE(SUB) (SUB)->distance
 308
 309 /* A data_dependence_relation represents a relation between two
 310    data_references A and B.  */
 311
 312 struct data_dependence_relation
 313 {
 314
 315   struct data_reference *a;
 316   struct data_reference *b;
 317
 318   /* A "yes/no/maybe" field for the dependence relation:
 319
 320      - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
 321        relation between A and B, and the description of this relation
 322        is given in the SUBSCRIPTS array,
 323
 324      - when "ARE_DEPENDENT == chrec_known", there is no dependence and
 325        SUBSCRIPTS is empty,
 326
 327      - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
 328        but the analyzer cannot be more specific.  */
 329   tree are_dependent;
 330
 331   /* If nonnull, COULD_BE_INDEPENDENT_P is true and the accesses are
 332      independent when the runtime addresses of OBJECT_A and OBJECT_B
 333      are different.  The addresses of both objects are invariant in the
 334      loop nest.  */
 335   tree object_a;
 336   tree object_b;
 337
 338   /* For each subscript in the dependence test, there is an element in
 339      this array.  This is the attribute that labels the edge A->B of
 340      the data_dependence_relation.  */
 341   vec<subscript_p> subscripts;
 342
 343   /* The analyzed loop nest.  */
 344   vec<loop_p> loop_nest;
 345
 346   /* The classic direction vector.  */
 347   vec<lambda_vector> dir_vects;
 348
 349   /* The classic distance vector.  */
 350   vec<lambda_vector> dist_vects;
 351
 352   /* Is the dependence reversed with respect to the lexicographic order?  */
 353   bool reversed_p;
 354
 355   /* When the dependence relation is affine, it can be represented by
 356      a distance vector.  */
 357   bool affine_p;
 358
 359   /* Set to true when the dependence relation is on the same data
 360      access.  */
 361   bool self_reference_p;
 362
 363   /* True if the dependence described is conservatively correct rather
 364      than exact, and if it is still possible for the accesses to be
 365      conditionally independent.  For example, the a and b references in:
 366
 367        struct s *a, *b;
 368        for (int i = 0; i < n; ++i)
 369          a->f[i] += b->f[i];
 370
 371      conservatively have a distance vector of (0), for the case in which
 372      a == b, but the accesses are independent if a != b.  Similarly,
 373      the a and b references in:
 374
 375        struct s *a, *b;
 376        for (int i = 0; i < n; ++i)
 377          a[0].f[i] += b[i].f[i];
 378
 379      conservatively have a distance vector of (0), but they are indepenent
 380      when a != b + i.  In contrast, the references in:
 381
 382        struct s *a;
 383        for (int i = 0; i < n; ++i)
 384          a->f[i] += a->f[i];
 385
 386      have the same distance vector of (0), but the accesses can never be
 387      independent.  */
 388   bool could_be_independent_p;
 389 };
 390
 391 typedef struct data_dependence_relation *ddr_p;
 392
 393 #define DDR_A(DDR) (DDR)->a
 394 #define DDR_B(DDR) (DDR)->b
 395 #define DDR_AFFINE_P(DDR) (DDR)->affine_p
 396 #define DDR_ARE_DEPENDENT(DDR) (DDR)->are_dependent
 397 #define DDR_OBJECT_A(DDR) (DDR)->object_a
 398 #define DDR_OBJECT_B(DDR) (DDR)->object_b
 399 #define DDR_SUBSCRIPTS(DDR) (DDR)->subscripts
 400 #define DDR_SUBSCRIPT(DDR, I) DDR_SUBSCRIPTS (DDR)[I]
 401 #define DDR_NUM_SUBSCRIPTS(DDR) DDR_SUBSCRIPTS (DDR).length ()
 402
 403 #define DDR_LOOP_NEST(DDR) (DDR)->loop_nest
 404 /* The size of the direction/distance vectors: the number of loops in
 405    the loop nest.  */
 406 #define DDR_NB_LOOPS(DDR) (DDR_LOOP_NEST (DDR).length ())
 407 #define DDR_SELF_REFERENCE(DDR) (DDR)->self_reference_p
 408
 409 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
 410 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
 411 #define DDR_NUM_DIST_VECTS(DDR) \
 412   (DDR_DIST_VECTS (DDR).length ())
 413 #define DDR_NUM_DIR_VECTS(DDR) \
 414   (DDR_DIR_VECTS (DDR).length ())
 415 #define DDR_DIR_VECT(DDR, I) \
 416   DDR_DIR_VECTS (DDR)[I]
 417 #define DDR_DIST_VECT(DDR, I) \
 418   DDR_DIST_VECTS (DDR)[I]
 419 #define DDR_REVERSED_P(DDR) (DDR)->reversed_p
 420 #define DDR_COULD_BE_INDEPENDENT_P(DDR) (DDR)->could_be_independent_p
 421
 422 \f
 423 opt_result dr_analyze_innermost (innermost_loop_behavior *, tree,
 424                                  class loop *, const gimple *);
 425 extern bool compute_data_dependences_for_loop (class loop *, bool,
 426                                                vec<loop_p> *,
 427                                                vec<data_reference_p> *,
 428                                                vec<ddr_p> *);
 429 extern void debug_ddrs (vec<ddr_p> );
 430 extern void dump_data_reference (FILE *, struct data_reference *);
 431 extern void debug (data_reference &ref);
 432 extern void debug (data_reference *ptr);
 433 extern void debug_data_reference (struct data_reference *);
 434 extern void debug_data_references (vec<data_reference_p> );
 435 extern void debug (vec<data_reference_p> &ref);
 436 extern void debug (vec<data_reference_p> *ptr);
 437 extern void debug_data_dependence_relation (struct data_dependence_relation *);
 438 extern void dump_data_dependence_relations (FILE *, vec<ddr_p> );
 439 extern void debug (vec<ddr_p> &ref);
 440 extern void debug (vec<ddr_p> *ptr);
 441 extern void debug_data_dependence_relations (vec<ddr_p> );
 442 extern void free_dependence_relation (struct data_dependence_relation *);
 443 extern void free_dependence_relations (vec<ddr_p> );
 444 extern void free_data_ref (data_reference_p);
 445 extern void free_data_refs (vec<data_reference_p> );
 446 extern opt_result find_data_references_in_stmt (class loop *, gimple *,
 447                                                 vec<data_reference_p> *);
 448 extern bool graphite_find_data_references_in_stmt (edge, loop_p, gimple *,
 449                                                    vec<data_reference_p> *);
 450 tree find_data_references_in_loop (class loop *, vec<data_reference_p> *);
 451 bool loop_nest_has_data_refs (loop_p loop);
 452 struct data_reference *create_data_ref (edge, loop_p, tree, gimple *, bool,
 453                                         bool);
 454 extern bool find_loop_nest (class loop *, vec<loop_p> *);
 455 extern struct data_dependence_relation *initialize_data_dependence_relation
 456      (struct data_reference *, struct data_reference *, vec<loop_p>);
 457 extern void compute_affine_dependence (struct data_dependence_relation *,
 458                                        loop_p);
 459 extern void compute_self_dependence (struct data_dependence_relation *);
 460 extern bool compute_all_dependences (vec<data_reference_p> ,
 461                                      vec<ddr_p> *,
 462                                      vec<loop_p>, bool);
 463 extern tree find_data_references_in_bb (class loop *, basic_block,
 464                                         vec<data_reference_p> *);
 465 extern unsigned int dr_alignment (innermost_loop_behavior *);
 466 extern tree get_base_for_alignment (tree, unsigned int *);
 467
 468 /* Return the alignment in bytes that DR is guaranteed to have at all
 469    times.  */
 470
 471 inline unsigned int
 472 dr_alignment (data_reference *dr)
 473 {
 474   return dr_alignment (&DR_INNERMOST (dr));
 475 }
 476
 477 extern bool dr_may_alias_p (const struct data_reference *,
 478                             const struct data_reference *, class loop *);
 479 extern bool dr_equal_offsets_p (struct data_reference *,
 480                                 struct data_reference *);
 481
 482 extern opt_result runtime_alias_check_p (ddr_p, class loop *, bool);
 483 extern int data_ref_compare_tree (tree, tree);
 484 extern void prune_runtime_alias_test_list (vec<dr_with_seg_len_pair_t> *,
 485                                            poly_uint64);
 486 extern void create_runtime_alias_checks (class loop *,
 487                                          vec<dr_with_seg_len_pair_t> *, tree*);
 488 extern tree dr_direction_indicator (struct data_reference *);
 489 extern tree dr_zero_step_indicator (struct data_reference *);
 490 extern bool dr_known_forward_stride_p (struct data_reference *);
 491
 492 /* Return true when the base objects of data references A and B are
 493    the same memory object.  */
 494
 495 static inline bool
 496 same_data_refs_base_objects (data_reference_p a, data_reference_p b)
 497 {
 498   return DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b)
 499     && operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0);
 500 }
 501
 502 /* Return true when the data references A and B are accessing the same
 503    memory object with the same access functions.  */
 504
 505 static inline bool
 506 same_data_refs (data_reference_p a, data_reference_p b)
 507 {
 508   unsigned int i;
 509
 510   /* The references are exactly the same.  */
 511   if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
 512     return true;
 513
 514   if (!same_data_refs_base_objects (a, b))
 515     return false;
 516
 517   for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
 518     if (!eq_evolutions_p (DR_ACCESS_FN (a, i), DR_ACCESS_FN (b, i)))
 519       return false;
 520
 521   return true;
 522 }
 523
 524 /* Returns true when all the dependences are computable.  */
 525
 526 inline bool
 527 known_dependences_p (vec<ddr_p> dependence_relations)
 528 {
 529   ddr_p ddr;
 530   unsigned int i;
 531
 532   FOR_EACH_VEC_ELT (dependence_relations, i, ddr)
 533     if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
 534       return false;
 535
 536   return true;
 537 }
 538
 539 /* Returns the dependence level for a vector DIST of size LENGTH.
 540    LEVEL = 0 means a lexicographic dependence, i.e. a dependence due
 541    to the sequence of statements, not carried by any loop.  */
 542
 543 static inline unsigned
 544 dependence_level (lambda_vector dist_vect, int length)
 545 {
 546   int i;
 547
 548   for (i = 0; i < length; i++)
 549     if (dist_vect[i] != 0)
 550       return i + 1;
 551
 552   return 0;
 553 }
 554
 555 /* Return the dependence level for the DDR relation.  */
 556
 557 static inline unsigned
 558 ddr_dependence_level (ddr_p ddr)
 559 {
 560   unsigned vector;
 561   unsigned level = 0;
 562
 563   if (DDR_DIST_VECTS (ddr).exists ())
 564     level = dependence_level (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr));
 565
 566   for (vector = 1; vector < DDR_NUM_DIST_VECTS (ddr); vector++)
 567     level = MIN (level, dependence_level (DDR_DIST_VECT (ddr, vector),
 568                                           DDR_NB_LOOPS (ddr)));
 569   return level;
 570 }
 571
 572 /* Return the index of the variable VAR in the LOOP_NEST array.  */
 573
 574 static inline int
 575 index_in_loop_nest (int var, vec<loop_p> loop_nest)
 576 {
 577   class loop *loopi;
 578   int var_index;
 579
 580   for (var_index = 0; loop_nest.iterate (var_index, &loopi); var_index++)
 581     if (loopi->num == var)
 582       return var_index;
 583
 584   gcc_unreachable ();
 585 }
 586
 587 /* Returns true when the data reference DR the form "A[i] = ..."
 588    with a stride equal to its unit type size.  */
 589
 590 static inline bool
 591 adjacent_dr_p (struct data_reference *dr)
 592 {
 593   /* If this is a bitfield store bail out.  */
 594   if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF
 595       && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1)))
 596     return false;
 597
 598   if (!DR_STEP (dr)
 599       || TREE_CODE (DR_STEP (dr)) != INTEGER_CST)
 600     return false;
 601
 602   return tree_int_cst_equal (fold_unary (ABS_EXPR, TREE_TYPE (DR_STEP (dr)),
 603                                          DR_STEP (dr)),
 604                              TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
 605 }
 606
 607 void split_constant_offset (tree , tree *, tree *);
 608
 609 /* Compute the greatest common divisor of a VECTOR of SIZE numbers.  */
 610
 611 static inline lambda_int
 612 lambda_vector_gcd (lambda_vector vector, int size)
 613 {
 614   int i;
 615   lambda_int gcd1 = 0;
 616
 617   if (size > 0)
 618     {
 619       gcd1 = vector[0];
 620       for (i = 1; i < size; i++)
 621         gcd1 = gcd (gcd1, vector[i]);
 622     }
 623   return gcd1;
 624 }
 625
 626 /* Allocate a new vector of given SIZE.  */
 627
 628 static inline lambda_vector
 629 lambda_vector_new (int size)
 630 {
 631   /* ???  We shouldn't abuse the GC allocator here.  */
 632   return ggc_cleared_vec_alloc<lambda_int> (size);
 633 }
 634
 635 /* Clear out vector VEC1 of length SIZE.  */
 636
 637 static inline void
 638 lambda_vector_clear (lambda_vector vec1, int size)
 639 {
 640   memset (vec1, 0, size * sizeof (*vec1));
 641 }
 642
 643 /* Returns true when the vector V is lexicographically positive, in
 644    other words, when the first nonzero element is positive.  */
 645
 646 static inline bool
 647 lambda_vector_lexico_pos (lambda_vector v,
 648                           unsigned n)
 649 {
 650   unsigned i;
 651   for (i = 0; i < n; i++)
 652     {
 653       if (v[i] == 0)
 654         continue;
 655       if (v[i] < 0)
 656         return false;
 657       if (v[i] > 0)
 658         return true;
 659     }
 660   return true;
 661 }
 662
 663 /* Return true if vector VEC1 of length SIZE is the zero vector.  */
 664
 665 static inline bool
 666 lambda_vector_zerop (lambda_vector vec1, int size)
 667 {
 668   int i;
 669   for (i = 0; i < size; i++)
 670     if (vec1[i] != 0)
 671       return false;
 672   return true;
 673 }
 674
 675 /* Allocate a matrix of M rows x  N cols.  */
 676
 677 static inline lambda_matrix
 678 lambda_matrix_new (int m, int n, struct obstack *lambda_obstack)
 679 {
 680   lambda_matrix mat;
 681   int i;
 682
 683   mat = XOBNEWVEC (lambda_obstack, lambda_vector, m);
 684
 685   for (i = 0; i < m; i++)
 686     mat[i] = XOBNEWVEC (lambda_obstack, lambda_int, n);
 687
 688   return mat;
 689 }
 690
 691 #endif  /* GCC_TREE_DATA_REF_H  */