/* Data references and dependences detectors. Copyright (C) 2003 Free Software Foundation, Inc. Contributed by Sebastian Pop <s.pop@laposte.net> 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 2, 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 COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef GCC_TREE_DATA_REF_H #define GCC_TREE_DATA_REF_H struct data_reference GTY(()) { /* An identifier. */ unsigned int id; /* A pointer to the statement that contains this DR. */ tree stmt; /* A pointer to the ARRAY_REF node. */ tree ref; /* The name of the array. */ tree base_name; /* A list of chrecs. */ varray_type access_fns; /* Auxiliary info specific to a pass. */ int aux; /* True when the data reference is in RHS of a stmt. */ bool is_read; }; #define DR_ID(DR) DR->id #define DR_STMT(DR) DR->stmt #define DR_REF(DR) DR->ref #define DR_BASE_NAME(DR) DR->base_name #define DR_ACCESS_FNS(DR) DR->access_fns #define DR_ACCESS_FN(DR, I) VARRAY_TREE (DR_ACCESS_FNS (DR), I) #define DR_NUM_DIMENSIONS(DR) VARRAY_ACTIVE_SIZE (DR_ACCESS_FNS (DR)) #define DR_IS_READ(DR) DR->is_read 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 }; /* 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 GTY(()) { /* A description of the iterations for which the elements are accessed twice. */ tree conflicting_iterations_in_a; tree conflicting_iterations_in_b; /* These fields store the information about the iteration domain validity of the dependence relation. */ tree last_conflict_in_a; tree last_conflict_in_b; /* 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, ie. a constant or a symbolic expression, but certainly not a chrec function. */ tree distance; /* Direction (or sign) of the distance. This more abstract (less precise) information is extracted from the distance field, for the convenience of some analyzers. */ enum data_dependence_direction direction; }; #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_IN_A(SUB) SUB->last_conflict_in_a #define SUB_LAST_CONFLICT_IN_B(SUB) SUB->last_conflict_in_b #define SUB_DISTANCE(SUB) SUB->distance #define SUB_DIRECTION(SUB) SUB->direction /* A data_dependence_relation represents a relation between two data_references A and B. */ struct data_dependence_relation GTY(()) { 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_BOT", there is no dependence and SUBSCRIPTS is empty, - when "ARE_DEPENDENT == CHREC_TOP", 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. */ varray_type subscripts; }; #define DDR_A(DDR) DDR->a #define DDR_B(DDR) DDR->b #define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent #define DDR_SUBSCRIPTS(DDR) DDR->subscripts #define DDR_SUBSCRIPTS_VECTOR_INIT(DDR, N) \ VARRAY_GENERIC_PTR_INIT (DDR_SUBSCRIPTS (DDR), N, "subscripts_vector"); #define DDR_SUBSCRIPT(DDR, I) VARRAY_GENERIC_PTR (DDR_SUBSCRIPTS (DDR), I) #define DDR_NUM_SUBSCRIPTS(DDR) VARRAY_ACTIVE_SIZE (DDR_SUBSCRIPTS (DDR)) extern void analyze_all_data_dependences (struct loops *); extern void compute_data_dependences_for_loop (unsigned, struct loop *, varray_type *, varray_type *, varray_type *, varray_type *); extern struct data_reference *analyze_array (tree, tree, bool); extern void dump_data_reference (FILE *, struct data_reference *); extern void dump_data_references (FILE *, varray_type); extern void dump_data_dependence_relation (FILE *, struct data_dependence_relation *); extern void dump_data_dependence_relations (FILE *, varray_type); extern void dump_data_dependence_direction (FILE *, enum data_dependence_direction); /* Inline functions. */ /* This is the simplest data dependence test: determines whether the data references A and B access the same array. */ static inline bool array_base_name_differ_p (struct data_reference *a, struct data_reference *b) { if (DR_BASE_NAME (a) == DR_BASE_NAME (b)) return false; if (TREE_CODE (DR_BASE_NAME (a)) == INDIRECT_REF && TREE_CODE (DR_BASE_NAME (b)) == INDIRECT_REF && TREE_OPERAND (DR_BASE_NAME (a), 0) == TREE_OPERAND (DR_BASE_NAME (b), 0)) return false; return true; } #endif /* GCC_TREE_DATA_REF_H */