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 struct dr_with_seg_len
 207 {
 208   dr_with_seg_len (data_reference_p d, tree len, unsigned HOST_WIDE_INT size,
 209                    unsigned int a)
 210     : dr (d), seg_len (len), access_size (size), align (a) {}
 211
 212   data_reference_p dr;
 213   /* The offset of the last access that needs to be checked minus
 214      the offset of the first.  */
 215   tree seg_len;
 216   /* A value that, when added to abs (SEG_LEN), gives the total number of
 217      bytes in the segment.  */
 218   poly_uint64 access_size;
 219   /* The minimum common alignment of DR's start address, SEG_LEN and
 220      ACCESS_SIZE.  */
 221   unsigned int align;
 222 };
 223
 224 /* This struct contains two dr_with_seg_len objects with aliasing data
 225    refs.  Two comparisons are generated from them.  */
 226
 227 struct dr_with_seg_len_pair_t
 228 {
 229   dr_with_seg_len_pair_t (const dr_with_seg_len& d1,
 230                                const dr_with_seg_len& d2)
 231     : first (d1), second (d2) {}
 232
 233   dr_with_seg_len first;
 234   dr_with_seg_len second;
 235 };
 236
 237 enum data_dependence_direction {
 238   dir_positive,
 239   dir_negative,
 240   dir_equal,
 241   dir_positive_or_negative,
 242   dir_positive_or_equal,
 243   dir_negative_or_equal,
 244   dir_star,
 245   dir_independent
 246 };
 247
 248 /* The description of the grid of iterations that overlap.  At most
 249    two loops are considered at the same time just now, hence at most
 250    two functions are needed.  For each of the functions, we store
 251    the vector of coefficients, f[0] + x * f[1] + y * f[2] + ...,
 252    where x, y, ... are variables.  */
 253
 254 #define MAX_DIM 2
 255
 256 /* Special values of N.  */
 257 #define NO_DEPENDENCE 0
 258 #define NOT_KNOWN (MAX_DIM + 1)
 259 #define CF_NONTRIVIAL_P(CF) ((CF)->n != NO_DEPENDENCE && (CF)->n != NOT_KNOWN)
 260 #define CF_NOT_KNOWN_P(CF) ((CF)->n == NOT_KNOWN)
 261 #define CF_NO_DEPENDENCE_P(CF) ((CF)->n == NO_DEPENDENCE)
 262
 263 typedef vec<tree> affine_fn;
 264
 265 struct conflict_function
 266 {
 267   unsigned n;
 268   affine_fn fns[MAX_DIM];
 269 };
 270
 271 /* What is a subscript?  Given two array accesses a subscript is the
 272    tuple composed of the access functions for a given dimension.
 273    Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
 274    subscripts: (f1, g1), (f2, g2), (f3, g3).  These three subscripts
 275    are stored in the data_dependence_relation structure under the form
 276    of an array of subscripts.  */
 277
 278 struct subscript
 279 {
 280   /* The access functions of the two references.  */
 281   tree access_fn[2];
 282
 283   /* A description of the iterations for which the elements are
 284      accessed twice.  */
 285   conflict_function *conflicting_iterations_in_a;
 286   conflict_function *conflicting_iterations_in_b;
 287
 288   /* This field stores the information about the iteration domain
 289      validity of the dependence relation.  */
 290   tree last_conflict;
 291
 292   /* Distance from the iteration that access a conflicting element in
 293      A to the iteration that access this same conflicting element in
 294      B.  The distance is a tree scalar expression, i.e. a constant or a
 295      symbolic expression, but certainly not a chrec function.  */
 296   tree distance;
 297 };
 298
 299 typedef struct subscript *subscript_p;
 300
 301 #define SUB_ACCESS_FN(SUB, I) (SUB)->access_fn[I]
 302 #define SUB_CONFLICTS_IN_A(SUB) (SUB)->conflicting_iterations_in_a
 303 #define SUB_CONFLICTS_IN_B(SUB) (SUB)->conflicting_iterations_in_b
 304 #define SUB_LAST_CONFLICT(SUB) (SUB)->last_conflict
 305 #define SUB_DISTANCE(SUB) (SUB)->distance
 306
 307 /* A data_dependence_relation represents a relation between two
 308    data_references A and B.  */
 309
 310 struct data_dependence_relation
 311 {
 312
 313   struct data_reference *a;
 314   struct data_reference *b;
 315
 316   /* A "yes/no/maybe" field for the dependence relation:
 317
 318      - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
 319        relation between A and B, and the description of this relation
 320        is given in the SUBSCRIPTS array,
 321
 322      - when "ARE_DEPENDENT == chrec_known", there is no dependence and
 323        SUBSCRIPTS is empty,
 324
 325      - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
 326        but the analyzer cannot be more specific.  */
 327   tree are_dependent;
 328
 329   /* If nonnull, COULD_BE_INDEPENDENT_P is true and the accesses are
 330      independent when the runtime addresses of OBJECT_A and OBJECT_B
 331      are different.  The addresses of both objects are invariant in the
 332      loop nest.  */
 333   tree object_a;
 334   tree object_b;
 335
 336   /* For each subscript in the dependence test, there is an element in
 337      this array.  This is the attribute that labels the edge A->B of
 338      the data_dependence_relation.  */
 339   vec<subscript_p> subscripts;
 340
 341   /* The analyzed loop nest.  */
 342   vec<loop_p> loop_nest;
 343
 344   /* The classic direction vector.  */
 345   vec<lambda_vector> dir_vects;
 346
 347   /* The classic distance vector.  */
 348   vec<lambda_vector> dist_vects;
 349
 350   /* Is the dependence reversed with respect to the lexicographic order?  */
 351   bool reversed_p;
 352
 353   /* When the dependence relation is affine, it can be represented by
 354      a distance vector.  */
 355   bool affine_p;
 356
 357   /* Set to true when the dependence relation is on the same data
 358      access.  */
 359   bool self_reference_p;
 360
 361   /* True if the dependence described is conservatively correct rather
 362      than exact, and if it is still possible for the accesses to be
 363      conditionally independent.  For example, the a and b references in:
 364
 365        struct s *a, *b;
 366        for (int i = 0; i < n; ++i)
 367          a->f[i] += b->f[i];
 368
 369      conservatively have a distance vector of (0), for the case in which
 370      a == b, but the accesses are independent if a != b.  Similarly,
 371      the a and b references in:
 372
 373        struct s *a, *b;
 374        for (int i = 0; i < n; ++i)
 375          a[0].f[i] += b[i].f[i];
 376
 377      conservatively have a distance vector of (0), but they are indepenent
 378      when a != b + i.  In contrast, the references in:
 379
 380        struct s *a;
 381        for (int i = 0; i < n; ++i)
 382          a->f[i] += a->f[i];
 383
 384      have the same distance vector of (0), but the accesses can never be
 385      independent.  */
 386   bool could_be_independent_p;
 387 };
 388
 389 typedef struct data_dependence_relation *ddr_p;
 390
 391 #define DDR_A(DDR) (DDR)->a
 392 #define DDR_B(DDR) (DDR)->b
 393 #define DDR_AFFINE_P(DDR) (DDR)->affine_p
 394 #define DDR_ARE_DEPENDENT(DDR) (DDR)->are_dependent
 395 #define DDR_OBJECT_A(DDR) (DDR)->object_a
 396 #define DDR_OBJECT_B(DDR) (DDR)->object_b
 397 #define DDR_SUBSCRIPTS(DDR) (DDR)->subscripts
 398 #define DDR_SUBSCRIPT(DDR, I) DDR_SUBSCRIPTS (DDR)[I]
 399 #define DDR_NUM_SUBSCRIPTS(DDR) DDR_SUBSCRIPTS (DDR).length ()
 400
 401 #define DDR_LOOP_NEST(DDR) (DDR)->loop_nest
 402 /* The size of the direction/distance vectors: the number of loops in
 403    the loop nest.  */
 404 #define DDR_NB_LOOPS(DDR) (DDR_LOOP_NEST (DDR).length ())
 405 #define DDR_SELF_REFERENCE(DDR) (DDR)->self_reference_p
 406
 407 #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
 408 #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
 409 #define DDR_NUM_DIST_VECTS(DDR) \
 410   (DDR_DIST_VECTS (DDR).length ())
 411 #define DDR_NUM_DIR_VECTS(DDR) \
 412   (DDR_DIR_VECTS (DDR).length ())
 413 #define DDR_DIR_VECT(DDR, I) \
 414   DDR_DIR_VECTS (DDR)[I]
 415 #define DDR_DIST_VECT(DDR, I) \
 416   DDR_DIST_VECTS (DDR)[I]
 417 #define DDR_REVERSED_P(DDR) (DDR)->reversed_p
 418 #define DDR_COULD_BE_INDEPENDENT_P(DDR) (DDR)->could_be_independent_p
 419
 420 \f
 421 opt_result dr_analyze_innermost (innermost_loop_behavior *, tree,
 422                                  struct loop *, const gimple *);
 423 extern bool compute_data_dependences_for_loop (struct loop *, bool,
 424                                                vec<loop_p> *,
 425                                                vec<data_reference_p> *,
 426                                                vec<ddr_p> *);
 427 extern void debug_ddrs (vec<ddr_p> );
 428 extern void dump_data_reference (FILE *, struct data_reference *);
 429 extern void debug (data_reference &ref);
 430 extern void debug (data_reference *ptr);
 431 extern void debug_data_reference (struct data_reference *);
 432 extern void debug_data_references (vec<data_reference_p> );
 433 extern void debug (vec<data_reference_p> &ref);
 434 extern void debug (vec<data_reference_p> *ptr);
 435 extern void debug_data_dependence_relation (struct data_dependence_relation *);
 436 extern void dump_data_dependence_relations (FILE *, vec<ddr_p> );
 437 extern void debug (vec<ddr_p> &ref);
 438 extern void debug (vec<ddr_p> *ptr);
 439 extern void debug_data_dependence_relations (vec<ddr_p> );
 440 extern void free_dependence_relation (struct data_dependence_relation *);
 441 extern void free_dependence_relations (vec<ddr_p> );
 442 extern void free_data_ref (data_reference_p);
 443 extern void free_data_refs (vec<data_reference_p> );
 444 extern opt_result find_data_references_in_stmt (struct loop *, gimple *,
 445                                                 vec<data_reference_p> *);
 446 extern bool graphite_find_data_references_in_stmt (edge, loop_p, gimple *,
 447                                                    vec<data_reference_p> *);
 448 tree find_data_references_in_loop (struct loop *, vec<data_reference_p> *);
 449 bool loop_nest_has_data_refs (loop_p loop);
 450 struct data_reference *create_data_ref (edge, loop_p, tree, gimple *, bool,
 451                                         bool);
 452 extern bool find_loop_nest (struct loop *, vec<loop_p> *);
 453 extern struct data_dependence_relation *initialize_data_dependence_relation
 454      (struct data_reference *, struct data_reference *, vec<loop_p>);
 455 extern void compute_affine_dependence (struct data_dependence_relation *,
 456                                        loop_p);
 457 extern void compute_self_dependence (struct data_dependence_relation *);
 458 extern bool compute_all_dependences (vec<data_reference_p> ,
 459                                      vec<ddr_p> *,
 460                                      vec<loop_p>, bool);
 461 extern tree find_data_references_in_bb (struct loop *, basic_block,
 462                                         vec<data_reference_p> *);
 463 extern unsigned int dr_alignment (innermost_loop_behavior *);
 464 extern tree get_base_for_alignment (tree, unsigned int *);
 465
 466 /* Return the alignment in bytes that DR is guaranteed to have at all
 467    times.  */
 468
 469 inline unsigned int
 470 dr_alignment (data_reference *dr)
 471 {
 472   return dr_alignment (&DR_INNERMOST (dr));
 473 }
 474
 475 extern bool dr_may_alias_p (const struct data_reference *,
 476                             const struct data_reference *, struct loop *);
 477 extern bool dr_equal_offsets_p (struct data_reference *,
 478                                 struct data_reference *);
 479
 480 extern opt_result runtime_alias_check_p (ddr_p, struct loop *, bool);
 481 extern int data_ref_compare_tree (tree, tree);
 482 extern void prune_runtime_alias_test_list (vec<dr_with_seg_len_pair_t> *,
 483                                            poly_uint64);
 484 extern void create_runtime_alias_checks (struct loop *,
 485                                          vec<dr_with_seg_len_pair_t> *, tree*);
 486 extern tree dr_direction_indicator (struct data_reference *);
 487 extern tree dr_zero_step_indicator (struct data_reference *);
 488 extern bool dr_known_forward_stride_p (struct data_reference *);
 489
 490 /* Return true when the base objects of data references A and B are
 491    the same memory object.  */
 492
 493 static inline bool
 494 same_data_refs_base_objects (data_reference_p a, data_reference_p b)
 495 {
 496   return DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b)
 497     && operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0);
 498 }
 499
 500 /* Return true when the data references A and B are accessing the same
 501    memory object with the same access functions.  */
 502
 503 static inline bool
 504 same_data_refs (data_reference_p a, data_reference_p b)
 505 {
 506   unsigned int i;
 507
 508   /* The references are exactly the same.  */
 509   if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
 510     return true;
 511
 512   if (!same_data_refs_base_objects (a, b))
 513     return false;
 514
 515   for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
 516     if (!eq_evolutions_p (DR_ACCESS_FN (a, i), DR_ACCESS_FN (b, i)))
 517       return false;
 518
 519   return true;
 520 }
 521
 522 /* Returns true when all the dependences are computable.  */
 523
 524 inline bool
 525 known_dependences_p (vec<ddr_p> dependence_relations)
 526 {
 527   ddr_p ddr;
 528   unsigned int i;
 529
 530   FOR_EACH_VEC_ELT (dependence_relations, i, ddr)
 531     if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
 532       return false;
 533
 534   return true;
 535 }
 536
 537 /* Returns the dependence level for a vector DIST of size LENGTH.
 538    LEVEL = 0 means a lexicographic dependence, i.e. a dependence due
 539    to the sequence of statements, not carried by any loop.  */
 540
 541 static inline unsigned
 542 dependence_level (lambda_vector dist_vect, int length)
 543 {
 544   int i;
 545
 546   for (i = 0; i < length; i++)
 547     if (dist_vect[i] != 0)
 548       return i + 1;
 549
 550   return 0;
 551 }
 552
 553 /* Return the dependence level for the DDR relation.  */
 554
 555 static inline unsigned
 556 ddr_dependence_level (ddr_p ddr)
 557 {
 558   unsigned vector;
 559   unsigned level = 0;
 560
 561   if (DDR_DIST_VECTS (ddr).exists ())
 562     level = dependence_level (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr));
 563
 564   for (vector = 1; vector < DDR_NUM_DIST_VECTS (ddr); vector++)
 565     level = MIN (level, dependence_level (DDR_DIST_VECT (ddr, vector),
 566                                           DDR_NB_LOOPS (ddr)));
 567   return level;
 568 }
 569
 570 /* Return the index of the variable VAR in the LOOP_NEST array.  */
 571
 572 static inline int
 573 index_in_loop_nest (int var, vec<loop_p> loop_nest)
 574 {
 575   struct loop *loopi;
 576   int var_index;
 577
 578   for (var_index = 0; loop_nest.iterate (var_index, &loopi); var_index++)
 579     if (loopi->num == var)
 580       return var_index;
 581
 582   gcc_unreachable ();
 583 }
 584
 585 /* Returns true when the data reference DR the form "A[i] = ..."
 586    with a stride equal to its unit type size.  */
 587
 588 static inline bool
 589 adjacent_dr_p (struct data_reference *dr)
 590 {
 591   /* If this is a bitfield store bail out.  */
 592   if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF
 593       && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1)))
 594     return false;
 595
 596   if (!DR_STEP (dr)
 597       || TREE_CODE (DR_STEP (dr)) != INTEGER_CST)
 598     return false;
 599
 600   return tree_int_cst_equal (fold_unary (ABS_EXPR, TREE_TYPE (DR_STEP (dr)),
 601                                          DR_STEP (dr)),
 602                              TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
 603 }
 604
 605 void split_constant_offset (tree , tree *, tree *);
 606
 607 /* Compute the greatest common divisor of a VECTOR of SIZE numbers.  */
 608
 609 static inline lambda_int
 610 lambda_vector_gcd (lambda_vector vector, int size)
 611 {
 612   int i;
 613   lambda_int gcd1 = 0;
 614
 615   if (size > 0)
 616     {
 617       gcd1 = vector[0];
 618       for (i = 1; i < size; i++)
 619         gcd1 = gcd (gcd1, vector[i]);
 620     }
 621   return gcd1;
 622 }
 623
 624 /* Allocate a new vector of given SIZE.  */
 625
 626 static inline lambda_vector
 627 lambda_vector_new (int size)
 628 {
 629   /* ???  We shouldn't abuse the GC allocator here.  */
 630   return ggc_cleared_vec_alloc<lambda_int> (size);
 631 }
 632
 633 /* Clear out vector VEC1 of length SIZE.  */
 634
 635 static inline void
 636 lambda_vector_clear (lambda_vector vec1, int size)
 637 {
 638   memset (vec1, 0, size * sizeof (*vec1));
 639 }
 640
 641 /* Returns true when the vector V is lexicographically positive, in
 642    other words, when the first nonzero element is positive.  */
 643
 644 static inline bool
 645 lambda_vector_lexico_pos (lambda_vector v,
 646                           unsigned n)
 647 {
 648   unsigned i;
 649   for (i = 0; i < n; i++)
 650     {
 651       if (v[i] == 0)
 652         continue;
 653       if (v[i] < 0)
 654         return false;
 655       if (v[i] > 0)
 656         return true;
 657     }
 658   return true;
 659 }
 660
 661 /* Return true if vector VEC1 of length SIZE is the zero vector.  */
 662
 663 static inline bool
 664 lambda_vector_zerop (lambda_vector vec1, int size)
 665 {
 666   int i;
 667   for (i = 0; i < size; i++)
 668     if (vec1[i] != 0)
 669       return false;
 670   return true;
 671 }
 672
 673 /* Allocate a matrix of M rows x  N cols.  */
 674
 675 static inline lambda_matrix
 676 lambda_matrix_new (int m, int n, struct obstack *lambda_obstack)
 677 {
 678   lambda_matrix mat;
 679   int i;
 680
 681   mat = XOBNEWVEC (lambda_obstack, lambda_vector, m);
 682
 683   for (i = 0; i < m; i++)
 684     mat[i] = XOBNEWVEC (lambda_obstack, lambda_int, n);
 685
 686   return mat;
 687 }
 688
 689 #endif  /* GCC_TREE_DATA_REF_H  */