318 lines
11 KiB
C
318 lines
11 KiB
C
/* Data references and dependences detectors.
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Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
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Contributed by Sebastian Pop <pop@cri.ensmp.fr>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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#ifndef GCC_TREE_DATA_REF_H
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#define GCC_TREE_DATA_REF_H
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#include "lambda.h"
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/** {base_address + offset + init} is the first location accessed by data-ref
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in the loop, and step is the stride of data-ref in the loop in bytes;
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e.g.:
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Example 1 Example 2
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data-ref a[j].b[i][j] a + x + 16B (a is int*)
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First location info:
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base_address &a a
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offset j_0*D_j + i_0*D_i + C_a x
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init C_b 16
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step D_j 4
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access_fn NULL {16, +, 1}
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Base object info:
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base_object a NULL
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access_fn <access_fns of indexes of b> NULL
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**/
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struct first_location_in_loop
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{
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tree base_address;
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tree offset;
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tree init;
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tree step;
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/* Access function related to first location in the loop. */
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VEC(tree,heap) *access_fns;
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};
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struct base_object_info
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{
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/* The object. */
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tree base_object;
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/* A list of chrecs. Access functions related to BASE_OBJECT. */
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VEC(tree,heap) *access_fns;
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};
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enum data_ref_type {
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ARRAY_REF_TYPE,
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POINTER_REF_TYPE
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};
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struct data_reference
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{
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/* A pointer to the statement that contains this DR. */
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tree stmt;
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/* A pointer to the ARRAY_REF node. */
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tree ref;
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/* Auxiliary info specific to a pass. */
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int aux;
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/* True when the data reference is in RHS of a stmt. */
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bool is_read;
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/* First location accessed by the data-ref in the loop. */
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struct first_location_in_loop first_location;
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/* Base object related info. */
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struct base_object_info object_info;
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/* Aliasing information. This field represents the symbol that
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should be aliased by a pointer holding the address of this data
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reference. If the original data reference was a pointer
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dereference, then this field contains the memory tag that should
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be used by the new vector-pointer. */
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tree memtag;
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struct ptr_info_def *ptr_info;
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subvar_t subvars;
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/* Alignment information. */
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/* The offset of the data-reference from its base in bytes. */
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tree misalignment;
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/* The maximum data-ref's alignment. */
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tree aligned_to;
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/* The type of the data-ref. */
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enum data_ref_type type;
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};
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typedef struct data_reference *data_reference_p;
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DEF_VEC_P(data_reference_p);
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DEF_VEC_ALLOC_P (data_reference_p, heap);
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#define DR_STMT(DR) (DR)->stmt
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#define DR_REF(DR) (DR)->ref
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#define DR_BASE_OBJECT(DR) (DR)->object_info.base_object
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#define DR_TYPE(DR) (DR)->type
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#define DR_ACCESS_FNS(DR)\
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(DR_TYPE(DR) == ARRAY_REF_TYPE ? \
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(DR)->object_info.access_fns : (DR)->first_location.access_fns)
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#define DR_ACCESS_FN(DR, I) VEC_index (tree, DR_ACCESS_FNS (DR), I)
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#define DR_NUM_DIMENSIONS(DR) VEC_length (tree, DR_ACCESS_FNS (DR))
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#define DR_IS_READ(DR) (DR)->is_read
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#define DR_BASE_ADDRESS(DR) (DR)->first_location.base_address
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#define DR_OFFSET(DR) (DR)->first_location.offset
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#define DR_INIT(DR) (DR)->first_location.init
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#define DR_STEP(DR) (DR)->first_location.step
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#define DR_MEMTAG(DR) (DR)->memtag
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#define DR_ALIGNED_TO(DR) (DR)->aligned_to
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#define DR_OFFSET_MISALIGNMENT(DR) (DR)->misalignment
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#define DR_PTR_INFO(DR) (DR)->ptr_info
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#define DR_SUBVARS(DR) (DR)->subvars
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#define DR_ACCESS_FNS_ADDR(DR) \
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(DR_TYPE(DR) == ARRAY_REF_TYPE ? \
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&((DR)->object_info.access_fns) : &((DR)->first_location.access_fns))
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#define DR_SET_ACCESS_FNS(DR, ACC_FNS) \
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{ \
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if (DR_TYPE(DR) == ARRAY_REF_TYPE) \
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(DR)->object_info.access_fns = ACC_FNS; \
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else \
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(DR)->first_location.access_fns = ACC_FNS; \
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}
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#define DR_FREE_ACCESS_FNS(DR) \
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{ \
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if (DR_TYPE(DR) == ARRAY_REF_TYPE) \
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VEC_free (tree, heap, (DR)->object_info.access_fns); \
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else \
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VEC_free (tree, heap, (DR)->first_location.access_fns); \
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}
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enum data_dependence_direction {
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dir_positive,
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dir_negative,
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dir_equal,
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dir_positive_or_negative,
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dir_positive_or_equal,
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dir_negative_or_equal,
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dir_star,
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dir_independent
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};
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/* What is a subscript? Given two array accesses a subscript is the
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tuple composed of the access functions for a given dimension.
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Example: Given A[f1][f2][f3] and B[g1][g2][g3], there are three
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subscripts: (f1, g1), (f2, g2), (f3, g3). These three subscripts
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are stored in the data_dependence_relation structure under the form
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of an array of subscripts. */
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struct subscript
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{
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/* A description of the iterations for which the elements are
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accessed twice. */
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tree conflicting_iterations_in_a;
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tree conflicting_iterations_in_b;
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/* This field stores the information about the iteration domain
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validity of the dependence relation. */
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tree last_conflict;
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/* Distance from the iteration that access a conflicting element in
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A to the iteration that access this same conflicting element in
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B. The distance is a tree scalar expression, i.e. a constant or a
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symbolic expression, but certainly not a chrec function. */
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tree distance;
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};
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typedef struct subscript *subscript_p;
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DEF_VEC_P(subscript_p);
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DEF_VEC_ALLOC_P (subscript_p, heap);
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#define SUB_CONFLICTS_IN_A(SUB) SUB->conflicting_iterations_in_a
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#define SUB_CONFLICTS_IN_B(SUB) SUB->conflicting_iterations_in_b
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#define SUB_LAST_CONFLICT(SUB) SUB->last_conflict
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#define SUB_DISTANCE(SUB) SUB->distance
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typedef struct loop *loop_p;
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DEF_VEC_P(loop_p);
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DEF_VEC_ALLOC_P (loop_p, heap);
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/* A data_dependence_relation represents a relation between two
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data_references A and B. */
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struct data_dependence_relation
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{
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struct data_reference *a;
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struct data_reference *b;
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/* When the dependence relation is affine, it can be represented by
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a distance vector. */
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bool affine_p;
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/* A "yes/no/maybe" field for the dependence relation:
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- when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
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relation between A and B, and the description of this relation
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is given in the SUBSCRIPTS array,
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- when "ARE_DEPENDENT == chrec_known", there is no dependence and
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SUBSCRIPTS is empty,
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- when "ARE_DEPENDENT == chrec_dont_know", there may be a dependence,
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but the analyzer cannot be more specific. */
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tree are_dependent;
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/* For each subscript in the dependence test, there is an element in
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this array. This is the attribute that labels the edge A->B of
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the data_dependence_relation. */
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VEC (subscript_p, heap) *subscripts;
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/* The analyzed loop nest. */
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VEC (loop_p, heap) *loop_nest;
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/* The classic direction vector. */
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VEC (lambda_vector, heap) *dir_vects;
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/* The classic distance vector. */
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VEC (lambda_vector, heap) *dist_vects;
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};
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typedef struct data_dependence_relation *ddr_p;
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DEF_VEC_P(ddr_p);
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DEF_VEC_ALLOC_P(ddr_p,heap);
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#define DDR_A(DDR) DDR->a
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#define DDR_B(DDR) DDR->b
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#define DDR_AFFINE_P(DDR) DDR->affine_p
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#define DDR_ARE_DEPENDENT(DDR) DDR->are_dependent
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#define DDR_SUBSCRIPTS(DDR) DDR->subscripts
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#define DDR_SUBSCRIPT(DDR, I) VEC_index (subscript_p, DDR_SUBSCRIPTS (DDR), I)
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#define DDR_NUM_SUBSCRIPTS(DDR) VEC_length (subscript_p, DDR_SUBSCRIPTS (DDR))
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#define DDR_LOOP_NEST(DDR) DDR->loop_nest
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/* The size of the direction/distance vectors: the number of loops in
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the loop nest. */
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#define DDR_NB_LOOPS(DDR) (VEC_length (loop_p, DDR_LOOP_NEST (DDR)))
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#define DDR_DIST_VECTS(DDR) ((DDR)->dist_vects)
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#define DDR_DIR_VECTS(DDR) ((DDR)->dir_vects)
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#define DDR_NUM_DIST_VECTS(DDR) \
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(VEC_length (lambda_vector, DDR_DIST_VECTS (DDR)))
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#define DDR_NUM_DIR_VECTS(DDR) \
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(VEC_length (lambda_vector, DDR_DIR_VECTS (DDR)))
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#define DDR_DIR_VECT(DDR, I) \
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VEC_index (lambda_vector, DDR_DIR_VECTS (DDR), I)
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#define DDR_DIST_VECT(DDR, I) \
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VEC_index (lambda_vector, DDR_DIST_VECTS (DDR), I)
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extern tree find_data_references_in_loop (struct loop *,
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VEC (data_reference_p, heap) **);
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extern void compute_data_dependences_for_loop (struct loop *, bool,
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VEC (data_reference_p, heap) **,
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VEC (ddr_p, heap) **);
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extern void print_direction_vector (FILE *, lambda_vector, int);
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extern void print_dir_vectors (FILE *, VEC (lambda_vector, heap) *, int);
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extern void print_dist_vectors (FILE *, VEC (lambda_vector, heap) *, int);
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extern void dump_subscript (FILE *, struct subscript *);
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extern void dump_ddrs (FILE *, VEC (ddr_p, heap) *);
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extern void dump_dist_dir_vectors (FILE *, VEC (ddr_p, heap) *);
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extern void dump_data_reference (FILE *, struct data_reference *);
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extern void dump_data_references (FILE *, VEC (data_reference_p, heap) *);
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extern void debug_data_dependence_relation (struct data_dependence_relation *);
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extern void dump_data_dependence_relation (FILE *,
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struct data_dependence_relation *);
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extern void dump_data_dependence_relations (FILE *, VEC (ddr_p, heap) *);
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extern void dump_data_dependence_direction (FILE *,
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enum data_dependence_direction);
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extern void free_dependence_relation (struct data_dependence_relation *);
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extern void free_dependence_relations (VEC (ddr_p, heap) *);
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extern void free_data_refs (VEC (data_reference_p, heap) *);
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extern struct data_reference *analyze_array (tree, tree, bool);
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extern void estimate_iters_using_array (tree, tree);
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/* Return the index of the variable VAR in the LOOP_NEST array. */
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static inline int
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index_in_loop_nest (int var, VEC (loop_p, heap) *loop_nest)
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{
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struct loop *loopi;
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int var_index;
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for (var_index = 0; VEC_iterate (loop_p, loop_nest, var_index, loopi);
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var_index++)
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if (loopi->num == var)
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break;
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return var_index;
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}
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/* In lambda-code.c */
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bool lambda_transform_legal_p (lambda_trans_matrix, int, VEC (ddr_p, heap) *);
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#endif /* GCC_TREE_DATA_REF_H */
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