| /* Data references and dependences detectors. |
| Copyright (C) 2003-2017 Free Software Foundation, Inc. |
| Contributed by Sebastian Pop <pop@cri.ensmp.fr> |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef GCC_TREE_DATA_REF_H |
| #define GCC_TREE_DATA_REF_H |
| |
| #include "graphds.h" |
| #include "tree-chrec.h" |
| |
| /* |
| innermost_loop_behavior describes the evolution of the address of the memory |
| reference in the innermost enclosing loop. The address is expressed as |
| BASE + STEP * # of iteration, and base is further decomposed as the base |
| pointer (BASE_ADDRESS), loop invariant offset (OFFSET) and |
| constant offset (INIT). Examples, in loop nest |
| |
| for (i = 0; i < 100; i++) |
| for (j = 3; j < 100; j++) |
| |
| Example 1 Example 2 |
| data-ref a[j].b[i][j] *(p + x + 16B + 4B * j) |
| |
| |
| innermost_loop_behavior |
| base_address &a p |
| offset i * D_i x |
| init 3 * D_j + offsetof (b) 28 |
| step D_j 4 |
| |
| */ |
| struct innermost_loop_behavior |
| { |
| tree base_address; |
| tree offset; |
| tree init; |
| tree step; |
| |
| /* Alignment information. ALIGNED_TO is set to the largest power of two |
| that divides OFFSET. */ |
| tree aligned_to; |
| }; |
| |
| /* Describes the evolutions of indices of the memory reference. The indices |
| are indices of the ARRAY_REFs, indexes in artificial dimensions |
| added for member selection of records and the operands of MEM_REFs. |
| BASE_OBJECT is the part of the reference that is loop-invariant |
| (note that this reference does not have to cover the whole object |
| being accessed, in which case UNCONSTRAINED_BASE is set; hence it is |
| not recommended to use BASE_OBJECT in any code generation). |
| For the examples above, |
| |
| base_object: a *(p + x + 4B * j_0) |
| indices: {j_0, +, 1}_2 {16, +, 4}_2 |
| 4 |
| {i_0, +, 1}_1 |
| {j_0, +, 1}_2 |
| */ |
| |
| struct indices |
| { |
| /* The object. */ |
| tree base_object; |
| |
| /* A list of chrecs. Access functions of the indices. */ |
| vec<tree> access_fns; |
| |
| /* Whether BASE_OBJECT is an access representing the whole object |
| or whether the access could not be constrained. */ |
| bool unconstrained_base; |
| }; |
| |
| struct dr_alias |
| { |
| /* The alias information that should be used for new pointers to this |
| location. */ |
| struct ptr_info_def *ptr_info; |
| }; |
| |
| /* An integer vector. A vector formally consists of an element of a vector |
| space. A vector space is a set that is closed under vector addition |
| and scalar multiplication. In this vector space, an element is a list of |
| integers. */ |
| typedef int *lambda_vector; |
| |
| /* An integer matrix. A matrix consists of m vectors of length n (IE |
| all vectors are the same length). */ |
| typedef lambda_vector *lambda_matrix; |
| |
| |
| |
| struct data_reference |
| { |
| /* A pointer to the statement that contains this DR. */ |
| gimple *stmt; |
| |
| /* A pointer to the memory reference. */ |
| tree ref; |
| |
| /* Auxiliary info specific to a pass. */ |
| void *aux; |
| |
| /* True when the data reference is in RHS of a stmt. */ |
| bool is_read; |
| |
| /* Behavior of the memory reference in the innermost loop. */ |
| struct innermost_loop_behavior innermost; |
| |
| /* Subscripts of this data reference. */ |
| struct indices indices; |
| |
| /* Alias information for the data reference. */ |
| struct dr_alias alias; |
| }; |
| |
| #define DR_STMT(DR) (DR)->stmt |
| #define DR_REF(DR) (DR)->ref |
| #define DR_BASE_OBJECT(DR) (DR)->indices.base_object |
| #define DR_UNCONSTRAINED_BASE(DR) (DR)->indices.unconstrained_base |
| #define DR_ACCESS_FNS(DR) (DR)->indices.access_fns |
| #define DR_ACCESS_FN(DR, I) DR_ACCESS_FNS (DR)[I] |
| #define DR_NUM_DIMENSIONS(DR) DR_ACCESS_FNS (DR).length () |
| #define DR_IS_READ(DR) (DR)->is_read |
| #define DR_IS_WRITE(DR) (!DR_IS_READ (DR)) |
| #define DR_BASE_ADDRESS(DR) (DR)->innermost.base_address |
| #define DR_OFFSET(DR) (DR)->innermost.offset |
| #define DR_INIT(DR) (DR)->innermost.init |
| #define DR_STEP(DR) (DR)->innermost.step |
| #define DR_PTR_INFO(DR) (DR)->alias.ptr_info |
| #define DR_ALIGNED_TO(DR) (DR)->innermost.aligned_to |
| #define DR_INNERMOST(DR) (DR)->innermost |
| |
| typedef struct data_reference *data_reference_p; |
| |
| enum data_dependence_direction { |
| dir_positive, |
| dir_negative, |
| dir_equal, |
| dir_positive_or_negative, |
| dir_positive_or_equal, |
| dir_negative_or_equal, |
| dir_star, |
| dir_independent |
| }; |
| |
| /* The description of the grid of iterations that overlap. At most |
| two loops are considered at the same time just now, hence at most |
| two functions are needed. For each of the functions, we store |
| the vector of coefficients, f[0] + x * f[1] + y * f[2] + ..., |
| where x, y, ... are variables. */ |
| |
| #define MAX_DIM 2 |
| |
| /* Special values of N. */ |
| #define NO_DEPENDENCE 0 |
| #define NOT_KNOWN (MAX_DIM + 1) |
| #define CF_NONTRIVIAL_P(CF) ((CF)->n != NO_DEPENDENCE && (CF)->n != NOT_KNOWN) |
| #define CF_NOT_KNOWN_P(CF) ((CF)->n == NOT_KNOWN) |
| #define CF_NO_DEPENDENCE_P(CF) ((CF)->n == NO_DEPENDENCE) |
| |
| typedef vec<tree> affine_fn; |
| |
| struct conflict_function |
| { |
| unsigned n; |
| affine_fn fns[MAX_DIM]; |
| }; |
| |
| /* What is a subscript? Given two array accesses a subscript is the |
| tuple composed of the access functions for a given dimension. |
| Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three |
| subscripts: (f1, g1), (f2, g2), (f3, g3). These three subscripts |
| are stored in the data_dependence_relation structure under the form |
| of an array of subscripts. */ |
| |
| struct subscript |
| { |
| /* A description of the iterations for which the elements are |
| accessed twice. */ |
| conflict_function *conflicting_iterations_in_a; |
| conflict_function *conflicting_iterations_in_b; |
| |
| /* This field stores the information about the iteration domain |
| validity of the dependence relation. */ |
| tree last_conflict; |
| |
| /* Distance from the iteration that access a conflicting element in |
| A to the iteration that access this same conflicting element in |
| B. The distance is a tree scalar expression, i.e. a constant or a |
| symbolic expression, but certainly not a chrec function. */ |
| tree distance; |
| }; |
| |
| typedef struct subscript *subscript_p; |
| |
| #define SUB_CONFLICTS_IN_A(SUB) SUB->conflicting_iterations_in_a |
| #define SUB_CONFLICTS_IN_B(SUB) SUB->conflicting_iterations_in_b |
| #define SUB_LAST_CONFLICT(SUB) SUB->last_conflict |
| #define SUB_DISTANCE(SUB) SUB->distance |
| |
| /* A data_dependence_relation represents a relation between two |
| data_references A and B. */ |
| |
| struct data_dependence_relation |
| { |
| |
| struct data_reference *a; |
| struct data_reference *b; |
| |
| /* A "yes/no/maybe" field for the dependence relation: |
| |
| - when "ARE_DEPENDENT == NULL_TREE", there exist a dependence |
| relation between A and B, and the description of this relation |
| is given in the SUBSCRIPTS array, |
| |
| - when "ARE_DEPENDENT == chrec_known", there is no dependence and |
| SUBSCRIPTS is empty, |
| |
| - when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence, |
| but the analyzer cannot be more specific. */ |
| tree are_dependent; |
| |
| /* For each subscript in the dependence test, there is an element in |
| this array. This is the attribute that labels the edge A->B of |
| the data_dependence_relation. */ |
| vec<subscript_p> subscripts; |
| |
| /* The analyzed loop nest. */ |
| vec<loop_p> loop_nest; |
| |
| /* The classic direction vector. */ |
| vec<lambda_vector> dir_vects; |
| |
| /* The classic distance vector. */ |
| vec<lambda_vector> dist_vects; |
| |
| /* An index in loop_nest for the innermost loop that varies for |
| this data dependence relation. */ |
| unsigned inner_loop; |
| |
| /* Is the dependence reversed with respect to the lexicographic order? */ |
| bool reversed_p; |
| |
| /* When the dependence relation is affine, it can be represented by |
| a distance vector. */ |
| bool affine_p; |
| |
| /* Set to true when the dependence relation is on the same data |
| access. */ |
| bool self_reference_p; |
| }; |
| |
| typedef struct data_dependence_relation *ddr_p; |
| |
| #define DDR_A(DDR) DDR->a |
| #define DDR_B(DDR) DDR->b |
| #define DDR_AFFINE_P(DDR) DDR->affine_p |
| #define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent |
| #define DDR_SUBSCRIPTS(DDR) DDR->subscripts |
| #define DDR_SUBSCRIPT(DDR, I) DDR_SUBSCRIPTS (DDR)[I] |
| #define DDR_NUM_SUBSCRIPTS(DDR) DDR_SUBSCRIPTS (DDR).length () |
| |
| #define DDR_LOOP_NEST(DDR) DDR->loop_nest |
| /* The size of the direction/distance vectors: the number of loops in |
| the loop nest. */ |
| #define DDR_NB_LOOPS(DDR) (DDR_LOOP_NEST (DDR).length ()) |
| #define DDR_INNER_LOOP(DDR) DDR->inner_loop |
| #define DDR_SELF_REFERENCE(DDR) DDR->self_reference_p |
| |
| #define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects) |
| #define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects) |
| #define DDR_NUM_DIST_VECTS(DDR) \ |
| (DDR_DIST_VECTS (DDR).length ()) |
| #define DDR_NUM_DIR_VECTS(DDR) \ |
| (DDR_DIR_VECTS (DDR).length ()) |
| #define DDR_DIR_VECT(DDR, I) \ |
| DDR_DIR_VECTS (DDR)[I] |
| #define DDR_DIST_VECT(DDR, I) \ |
| DDR_DIST_VECTS (DDR)[I] |
| #define DDR_REVERSED_P(DDR) DDR->reversed_p |
| |
| |
| bool dr_analyze_innermost (struct data_reference *, struct loop *); |
| extern bool compute_data_dependences_for_loop (struct loop *, bool, |
| vec<loop_p> *, |
| vec<data_reference_p> *, |
| vec<ddr_p> *); |
| extern void debug_ddrs (vec<ddr_p> ); |
| extern void dump_data_reference (FILE *, struct data_reference *); |
| extern void debug (data_reference &ref); |
| extern void debug (data_reference *ptr); |
| extern void debug_data_reference (struct data_reference *); |
| extern void debug_data_references (vec<data_reference_p> ); |
| extern void debug (vec<data_reference_p> &ref); |
| extern void debug (vec<data_reference_p> *ptr); |
| extern void debug_data_dependence_relation (struct data_dependence_relation *); |
| extern void dump_data_dependence_relations (FILE *, vec<ddr_p> ); |
| extern void debug (vec<ddr_p> &ref); |
| extern void debug (vec<ddr_p> *ptr); |
| extern void debug_data_dependence_relations (vec<ddr_p> ); |
| extern void free_dependence_relation (struct data_dependence_relation *); |
| extern void free_dependence_relations (vec<ddr_p> ); |
| extern void free_data_ref (data_reference_p); |
| extern void free_data_refs (vec<data_reference_p> ); |
| extern bool find_data_references_in_stmt (struct loop *, gimple *, |
| vec<data_reference_p> *); |
| extern bool graphite_find_data_references_in_stmt (loop_p, loop_p, gimple *, |
| vec<data_reference_p> *); |
| tree find_data_references_in_loop (struct loop *, vec<data_reference_p> *); |
| bool loop_nest_has_data_refs (loop_p loop); |
| struct data_reference *create_data_ref (loop_p, loop_p, tree, gimple *, bool); |
| extern bool find_loop_nest (struct loop *, vec<loop_p> *); |
| extern struct data_dependence_relation *initialize_data_dependence_relation |
| (struct data_reference *, struct data_reference *, vec<loop_p>); |
| extern void compute_affine_dependence (struct data_dependence_relation *, |
| loop_p); |
| extern void compute_self_dependence (struct data_dependence_relation *); |
| extern bool compute_all_dependences (vec<data_reference_p> , |
| vec<ddr_p> *, |
| vec<loop_p>, bool); |
| extern tree find_data_references_in_bb (struct loop *, basic_block, |
| vec<data_reference_p> *); |
| |
| extern bool dr_may_alias_p (const struct data_reference *, |
| const struct data_reference *, struct loop *); |
| extern bool dr_equal_offsets_p (struct data_reference *, |
| struct data_reference *); |
| |
| /* Return true when the base objects of data references A and B are |
| the same memory object. */ |
| |
| static inline bool |
| same_data_refs_base_objects (data_reference_p a, data_reference_p b) |
| { |
| return DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b) |
| && operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0); |
| } |
| |
| /* Return true when the data references A and B are accessing the same |
| memory object with the same access functions. */ |
| |
| static inline bool |
| same_data_refs (data_reference_p a, data_reference_p b) |
| { |
| unsigned int i; |
| |
| /* The references are exactly the same. */ |
| if (operand_equal_p (DR_REF (a), DR_REF (b), 0)) |
| return true; |
| |
| if (!same_data_refs_base_objects (a, b)) |
| return false; |
| |
| for (i = 0; i < DR_NUM_DIMENSIONS (a); i++) |
| if (!eq_evolutions_p (DR_ACCESS_FN (a, i), DR_ACCESS_FN (b, i))) |
| return false; |
| |
| return true; |
| } |
| |
| /* Return true when the DDR contains two data references that have the |
| same access functions. */ |
| |
| static inline bool |
| same_access_functions (const struct data_dependence_relation *ddr) |
| { |
| unsigned i; |
| |
| for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) |
| if (!eq_evolutions_p (DR_ACCESS_FN (DDR_A (ddr), i), |
| DR_ACCESS_FN (DDR_B (ddr), i))) |
| return false; |
| |
| return true; |
| } |
| |
| /* Returns true when all the dependences are computable. */ |
| |
| inline bool |
| known_dependences_p (vec<ddr_p> dependence_relations) |
| { |
| ddr_p ddr; |
| unsigned int i; |
| |
| FOR_EACH_VEC_ELT (dependence_relations, i, ddr) |
| if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) |
| return false; |
| |
| return true; |
| } |
| |
| /* Returns the dependence level for a vector DIST of size LENGTH. |
| LEVEL = 0 means a lexicographic dependence, i.e. a dependence due |
| to the sequence of statements, not carried by any loop. */ |
| |
| static inline unsigned |
| dependence_level (lambda_vector dist_vect, int length) |
| { |
| int i; |
| |
| for (i = 0; i < length; i++) |
| if (dist_vect[i] != 0) |
| return i + 1; |
| |
| return 0; |
| } |
| |
| /* Return the dependence level for the DDR relation. */ |
| |
| static inline unsigned |
| ddr_dependence_level (ddr_p ddr) |
| { |
| unsigned vector; |
| unsigned level = 0; |
| |
| if (DDR_DIST_VECTS (ddr).exists ()) |
| level = dependence_level (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr)); |
| |
| for (vector = 1; vector < DDR_NUM_DIST_VECTS (ddr); vector++) |
| level = MIN (level, dependence_level (DDR_DIST_VECT (ddr, vector), |
| DDR_NB_LOOPS (ddr))); |
| return level; |
| } |
| |
| /* Return the index of the variable VAR in the LOOP_NEST array. */ |
| |
| static inline int |
| index_in_loop_nest (int var, vec<loop_p> loop_nest) |
| { |
| struct loop *loopi; |
| int var_index; |
| |
| for (var_index = 0; loop_nest.iterate (var_index, &loopi); |
| var_index++) |
| if (loopi->num == var) |
| break; |
| |
| return var_index; |
| } |
| |
| /* Returns true when the data reference DR the form "A[i] = ..." |
| with a stride equal to its unit type size. */ |
| |
| static inline bool |
| adjacent_dr_p (struct data_reference *dr) |
| { |
| /* If this is a bitfield store bail out. */ |
| if (TREE_CODE (DR_REF (dr)) == COMPONENT_REF |
| && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (dr), 1))) |
| return false; |
| |
| if (!DR_STEP (dr) |
| || TREE_CODE (DR_STEP (dr)) != INTEGER_CST) |
| return false; |
| |
| return tree_int_cst_equal (fold_unary (ABS_EXPR, TREE_TYPE (DR_STEP (dr)), |
| DR_STEP (dr)), |
| TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr)))); |
| } |
| |
| void split_constant_offset (tree , tree *, tree *); |
| |
| /* Compute the greatest common divisor of a VECTOR of SIZE numbers. */ |
| |
| static inline int |
| lambda_vector_gcd (lambda_vector vector, int size) |
| { |
| int i; |
| int gcd1 = 0; |
| |
| if (size > 0) |
| { |
| gcd1 = vector[0]; |
| for (i = 1; i < size; i++) |
| gcd1 = gcd (gcd1, vector[i]); |
| } |
| return gcd1; |
| } |
| |
| /* Allocate a new vector of given SIZE. */ |
| |
| static inline lambda_vector |
| lambda_vector_new (int size) |
| { |
| /* ??? We shouldn't abuse the GC allocator here. */ |
| return ggc_cleared_vec_alloc<int> (size); |
| } |
| |
| /* Clear out vector VEC1 of length SIZE. */ |
| |
| static inline void |
| lambda_vector_clear (lambda_vector vec1, int size) |
| { |
| memset (vec1, 0, size * sizeof (*vec1)); |
| } |
| |
| /* Returns true when the vector V is lexicographically positive, in |
| other words, when the first nonzero element is positive. */ |
| |
| static inline bool |
| lambda_vector_lexico_pos (lambda_vector v, |
| unsigned n) |
| { |
| unsigned i; |
| for (i = 0; i < n; i++) |
| { |
| if (v[i] == 0) |
| continue; |
| if (v[i] < 0) |
| return false; |
| if (v[i] > 0) |
| return true; |
| } |
| return true; |
| } |
| |
| /* Return true if vector VEC1 of length SIZE is the zero vector. */ |
| |
| static inline bool |
| lambda_vector_zerop (lambda_vector vec1, int size) |
| { |
| int i; |
| for (i = 0; i < size; i++) |
| if (vec1[i] != 0) |
| return false; |
| return true; |
| } |
| |
| /* Allocate a matrix of M rows x N cols. */ |
| |
| static inline lambda_matrix |
| lambda_matrix_new (int m, int n, struct obstack *lambda_obstack) |
| { |
| lambda_matrix mat; |
| int i; |
| |
| mat = XOBNEWVEC (lambda_obstack, lambda_vector, m); |
| |
| for (i = 0; i < m; i++) |
| mat[i] = XOBNEWVEC (lambda_obstack, int, n); |
| |
| return mat; |
| } |
| |
| #endif /* GCC_TREE_DATA_REF_H */ |