/* Data references and dependences detectors.
- Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ 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 2, or (at your option) any later
+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
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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+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 "lambda.h"
#include "omega.h"
+#include "tree-chrec.h"
/*
innermost_loop_behavior describes the evolution of the address of the memory
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
/* The alias information that should be used for new pointers to this
location. SYMBOL_TAG is either a DECL or a SYMBOL_MEMORY_TAG. */
tree symbol_tag;
- subvar_t subvars;
struct ptr_info_def *ptr_info;
/* The set of virtual operands corresponding to this memory reference,
bitmap vops;
};
+typedef struct scop *scop_p;
+
+/* Each vector of the access matrix represents a linear access
+ function for a subscript. First elements correspond to the
+ leftmost indices, ie. for a[i][j] the first vector corresponds to
+ the subscript in "i". The elements of a vector are relative to
+ the loop nests in which the data reference is considered,
+ i.e. the vector is relative to the SCoP that provides the context
+ in which this data reference occurs.
+
+ For example, in
+
+ | loop_1
+ | loop_2
+ | a[i+3][2*j+n-1]
+
+ if "i" varies in loop_1 and "j" varies in loop_2, the access
+ matrix with respect to the loop nest {loop_1, loop_2} is:
+
+ | loop_1 loop_2 param_n cst
+ | 1 0 0 3
+ | 0 2 1 -1
+
+ whereas the access matrix with respect to loop_2 considers "i" as
+ a parameter:
+
+ | loop_2 param_i param_n cst
+ | 0 1 0 3
+ | 2 0 1 -1
+*/
+struct access_matrix
+{
+ VEC (loop_p, heap) *loop_nest;
+ int nb_induction_vars;
+ VEC (tree, heap) *parameters;
+ VEC (lambda_vector, gc) *matrix;
+};
+
+#define AM_LOOP_NEST(M) (M)->loop_nest
+#define AM_NB_INDUCTION_VARS(M) (M)->nb_induction_vars
+#define AM_PARAMETERS(M) (M)->parameters
+#define AM_MATRIX(M) (M)->matrix
+#define AM_NB_PARAMETERS(M) (VEC_length (tree, AM_PARAMETERS(M)))
+#define AM_CONST_COLUMN_INDEX(M) (AM_NB_INDUCTION_VARS (M) + AM_NB_PARAMETERS (M))
+#define AM_NB_COLUMNS(M) (AM_NB_INDUCTION_VARS (M) + AM_NB_PARAMETERS (M) + 1)
+#define AM_GET_SUBSCRIPT_ACCESS_VECTOR(M, I) VEC_index (lambda_vector, AM_MATRIX (M), I)
+#define AM_GET_ACCESS_MATRIX_ELEMENT(M, I, J) AM_GET_SUBSCRIPT_ACCESS_VECTOR (M, I)[J]
+
+/* Return the column in the access matrix of LOOP_NUM. */
+
+static inline int
+am_vector_index_for_loop (struct access_matrix *access_matrix, int loop_num)
+{
+ int i;
+ loop_p l;
+
+ for (i = 0; VEC_iterate (loop_p, AM_LOOP_NEST (access_matrix), i, l); i++)
+ if (l->num == loop_num)
+ return i;
+
+ gcc_unreachable();
+}
+
+int access_matrix_get_index_for_parameter (tree, struct access_matrix *);
+
struct data_reference
{
/* A pointer to the statement that contains this DR. */
- tree stmt;
+ gimple stmt;
/* A pointer to the memory reference. */
tree ref;
/* Behavior of the memory reference in the innermost loop. */
struct innermost_loop_behavior innermost;
- /* Decomposition to indices for alias analysis. */
+ /* Subscripts of this data reference. */
struct indices indices;
/* Alias information for the data reference. */
struct dr_alias alias;
-};
-typedef struct data_reference *data_reference_p;
-DEF_VEC_P(data_reference_p);
-DEF_VEC_ALLOC_P (data_reference_p, heap);
+ /* The SCoP in which the data reference was analyzed. */
+ scop_p scop;
+ /* Matrix representation for the data access functions. */
+ struct access_matrix *access_matrix;
+};
+
+#define DR_SCOP(DR) (DR)->scop
#define DR_STMT(DR) (DR)->stmt
#define DR_REF(DR) (DR)->ref
#define DR_BASE_OBJECT(DR) (DR)->indices.base_object
#define DR_STEP(DR) (DR)->innermost.step
#define DR_SYMBOL_TAG(DR) (DR)->alias.symbol_tag
#define DR_PTR_INFO(DR) (DR)->alias.ptr_info
-#define DR_SUBVARS(DR) (DR)->alias.subvars
#define DR_VOPS(DR) (DR)->alias.vops
#define DR_ALIGNED_TO(DR) (DR)->innermost.aligned_to
+#define DR_ACCESS_MATRIX(DR) (DR)->access_matrix
+
+typedef struct data_reference *data_reference_p;
+DEF_VEC_P(data_reference_p);
+DEF_VEC_ALLOC_P (data_reference_p, heap);
enum data_dependence_direction {
dir_positive,
a distance vector. */
bool affine_p;
+ /* Set to true when the dependence relation is on the same data
+ access. */
+ bool self_reference_p;
+
/* A "yes/no/maybe" field for the dependence relation:
- when "ARE_DEPENDENT == NULL_TREE", there exist a dependence
/* The classic distance vector. */
VEC (lambda_vector, heap) *dist_vects;
+
+ /* Is the dependence reversed with respect to the lexicographic order? */
+ bool reversed_p;
};
typedef struct data_dependence_relation *ddr_p;
the loop nest. */
#define DDR_NB_LOOPS(DDR) (VEC_length (loop_p, DDR_LOOP_NEST (DDR)))
#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)
VEC_index (lambda_vector, DDR_DIR_VECTS (DDR), I)
#define DDR_DIST_VECT(DDR, I) \
VEC_index (lambda_vector, DDR_DIST_VECTS (DDR), I)
+#define DDR_REVERSED_P(DDR) DDR->reversed_p
\f
DEF_VEC_O (data_ref_loc);
DEF_VEC_ALLOC_O (data_ref_loc, heap);
-bool get_references_in_stmt (tree, VEC (data_ref_loc, heap) **);
-void dr_analyze_innermost (struct data_reference *);
-extern void compute_data_dependences_for_loop (struct loop *, bool,
+bool get_references_in_stmt (gimple, VEC (data_ref_loc, heap) **);
+bool dr_analyze_innermost (struct data_reference *);
+extern bool compute_data_dependences_for_loop (struct loop *, bool,
VEC (data_reference_p, heap) **,
VEC (ddr_p, heap) **);
+extern tree find_data_references_in_loop (struct loop *,
+ VEC (data_reference_p, heap) **);
extern void print_direction_vector (FILE *, lambda_vector, int);
extern void print_dir_vectors (FILE *, VEC (lambda_vector, heap) *, int);
extern void print_dist_vectors (FILE *, VEC (lambda_vector, heap) *, int);
extern void dump_data_dependence_relation (FILE *,
struct data_dependence_relation *);
extern void dump_data_dependence_relations (FILE *, VEC (ddr_p, heap) *);
+extern void debug_data_dependence_relations (VEC (ddr_p, heap) *);
extern void dump_data_dependence_direction (FILE *,
enum data_dependence_direction);
extern void free_dependence_relation (struct data_dependence_relation *);
extern void free_dependence_relations (VEC (ddr_p, heap) *);
+extern void free_data_ref (data_reference_p);
extern void free_data_refs (VEC (data_reference_p, heap) *);
-struct data_reference *create_data_ref (struct loop *, tree, tree, bool);
-bool find_loop_nest (struct loop *, VEC (loop_p, heap) **);
-void compute_all_dependences (VEC (data_reference_p, heap) *,
- VEC (ddr_p, heap) **, VEC (loop_p, heap) *, bool);
+extern bool find_data_references_in_stmt (struct loop *, gimple,
+ VEC (data_reference_p, heap) **);
+struct data_reference *create_data_ref (struct loop *, tree, gimple, bool);
+extern bool find_loop_nest (struct loop *, VEC (loop_p, heap) **);
+extern void compute_all_dependences (VEC (data_reference_p, heap) *,
+ VEC (ddr_p, heap) **, VEC (loop_p, heap) *,
+ bool);
+
+extern void create_rdg_vertices (struct graph *, VEC (gimple, heap) *);
+extern bool dr_may_alias_p (const struct data_reference *,
+ const struct data_reference *);
+extern bool stmt_simple_memref_p (struct loop *, gimple, tree);
+
+/* 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;
+}
+
+/* Return true when DDR is an anti-dependence relation. */
+
+static inline bool
+ddr_is_anti_dependent (ddr_p ddr)
+{
+ return (DDR_ARE_DEPENDENT (ddr) == NULL_TREE
+ && DR_IS_READ (DDR_A (ddr))
+ && !DR_IS_READ (DDR_B (ddr))
+ && !same_access_functions (ddr));
+}
+
+/* Return true when DEPENDENCE_RELATIONS contains an anti-dependence. */
+
+static inline bool
+ddrs_have_anti_deps (VEC (ddr_p, heap) *dependence_relations)
+{
+ unsigned i;
+ ddr_p ddr;
+
+ for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
+ if (ddr_is_anti_dependent (ddr))
+ return true;
+
+ return false;
+}
+
+/* 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))
+ 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;
+}
+
+\f
+
+/* A Reduced Dependence Graph (RDG) vertex representing a statement. */
+typedef struct rdg_vertex
+{
+ /* The statement represented by this vertex. */
+ gimple stmt;
+
+ /* True when the statement contains a write to memory. */
+ bool has_mem_write;
+
+ /* True when the statement contains a read from memory. */
+ bool has_mem_reads;
+} *rdg_vertex_p;
+
+#define RDGV_STMT(V) ((struct rdg_vertex *) ((V)->data))->stmt
+#define RDGV_HAS_MEM_WRITE(V) ((struct rdg_vertex *) ((V)->data))->has_mem_write
+#define RDGV_HAS_MEM_READS(V) ((struct rdg_vertex *) ((V)->data))->has_mem_reads
+#define RDG_STMT(RDG, I) RDGV_STMT (&(RDG->vertices[I]))
+#define RDG_MEM_WRITE_STMT(RDG, I) RDGV_HAS_MEM_WRITE (&(RDG->vertices[I]))
+#define RDG_MEM_READS_STMT(RDG, I) RDGV_HAS_MEM_READS (&(RDG->vertices[I]))
+
+void dump_rdg_vertex (FILE *, struct graph *, int);
+void debug_rdg_vertex (struct graph *, int);
+void dump_rdg_component (FILE *, struct graph *, int, bitmap);
+void debug_rdg_component (struct graph *, int);
+void dump_rdg (FILE *, struct graph *);
+void debug_rdg (struct graph *);
+void dot_rdg (struct graph *);
+int rdg_vertex_for_stmt (struct graph *, gimple);
+
+/* Data dependence type. */
+
+enum rdg_dep_type
+{
+ /* Read After Write (RAW). */
+ flow_dd = 'f',
+
+ /* Write After Read (WAR). */
+ anti_dd = 'a',
+
+ /* Write After Write (WAW). */
+ output_dd = 'o',
+
+ /* Read After Read (RAR). */
+ input_dd = 'i'
+};
+
+/* Dependence information attached to an edge of the RDG. */
+
+typedef struct rdg_edge
+{
+ /* Type of the dependence. */
+ enum rdg_dep_type type;
+
+ /* Levels of the dependence: the depth of the loops that carry the
+ dependence. */
+ unsigned level;
+
+ /* Dependence relation between data dependences, NULL when one of
+ the vertices is a scalar. */
+ ddr_p relation;
+} *rdg_edge_p;
+
+#define RDGE_TYPE(E) ((struct rdg_edge *) ((E)->data))->type
+#define RDGE_LEVEL(E) ((struct rdg_edge *) ((E)->data))->level
+#define RDGE_RELATION(E) ((struct rdg_edge *) ((E)->data))->relation
+
+struct graph *build_rdg (struct loop *);
+struct graph *build_empty_rdg (int);
+void free_rdg (struct graph *);
/* Return the index of the variable VAR in the LOOP_NEST array. */
return var_index;
}
+void stores_from_loop (struct loop *, VEC (gimple, heap) **);
+void remove_similar_memory_refs (VEC (gimple, heap) **);
+bool rdg_defs_used_in_other_loops_p (struct graph *, int);
+bool have_similar_memory_accesses (gimple, gimple);
+
+/* Determines whether RDG vertices V1 and V2 access to similar memory
+ locations, in which case they have to be in the same partition. */
+
+static inline bool
+rdg_has_similar_memory_accesses (struct graph *rdg, int v1, int v2)
+{
+ return have_similar_memory_accesses (RDG_STMT (rdg, v1),
+ RDG_STMT (rdg, v2));
+}
+
/* In lambda-code.c */
-bool lambda_transform_legal_p (lambda_trans_matrix, int, VEC (ddr_p, heap) *);
+bool lambda_transform_legal_p (lambda_trans_matrix, int,
+ VEC (ddr_p, heap) *);
+void lambda_collect_parameters (VEC (data_reference_p, heap) *,
+ VEC (tree, heap) **);
+bool lambda_compute_access_matrices (VEC (data_reference_p, heap) *,
+ VEC (tree, heap) *, VEC (loop_p, heap) *);
+
+/* In tree-data-ref.c */
+void split_constant_offset (tree , tree *, tree *);
+
+/* Strongly connected components of the reduced data dependence graph. */
+
+typedef struct rdg_component
+{
+ int num;
+ VEC (int, heap) *vertices;
+} *rdgc;
+
+DEF_VEC_P (rdgc);
+DEF_VEC_ALLOC_P (rdgc, heap);
+
+DEF_VEC_P (bitmap);
+DEF_VEC_ALLOC_P (bitmap, heap);
#endif /* GCC_TREE_DATA_REF_H */
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