graphite.h

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/* Graphite polyhedral representation.
   Copyright (C) 2009-2024 Free Software Foundation, Inc.
   Contributed by Sebastian Pop <sebastian.pop@amd.com> and
   Tobias Grosser <grosser@fim.uni-passau.de>.
 
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_GRAPHITE_POLY_H
#define GCC_GRAPHITE_POLY_H
 
#include "sese.h"
 
typedef struct poly_dr *poly_dr_p;
 
typedef struct poly_bb *poly_bb_p;
 
typedef struct scop *scop_p;
 
typedef unsigned graphite_dim_t;
 
inline graphite_dim_t scop_nb_params (scop_p);
 
/* A data reference can write or read some memory or we
   just know it may write some memory.  */
enum poly_dr_type
{
  PDR_READ,
  /* PDR_MAY_READs are represented using PDR_READS.  This does not
     limit the expressiveness.  */
  PDR_WRITE,
  PDR_MAY_WRITE
};
 
struct poly_dr
{
  /* An identifier for this PDR.  */
  int id;
 
  /* The number of data refs identical to this one in the PBB.  */
  int nb_refs;
 
  /* A pointer to the gimple stmt containing this reference.  */
  gimple *stmt;
 
  /* A pointer to the PBB that contains this data reference.  */
  poly_bb_p pbb;
 
  enum poly_dr_type type;
 
  /* The access polyhedron contains the polyhedral space this data
     reference will access.
 
     The polyhedron contains these dimensions:
 
     - The alias set (a):
     Every memory access is classified in at least one alias set.
 
     - The subscripts (s_0, ..., s_n):
     The memory is accessed using zero or more subscript dimensions.
 
     - The iteration domain (variables and parameters)
 
     Do not hardcode the dimensions.  Use the following accessor functions:
     - pdr_alias_set_dim
     - pdr_subscript_dim
     - pdr_iterator_dim
     - pdr_parameter_dim
 
     Example:
 
     | int A[1335][123];
     | int *p = malloc ();
     |
     | k = ...
     | for i
     |   {
     |     if (unknown_function ())
     |       p = A;
     |       ... = p[?][?];
     |     for j
     |       A[i][j+k] = m;
     |   }
 
     The data access A[i][j+k] in alias set "5" is described like this:
 
     | i   j   k   a  s0  s1   1
     | 0   0   0   1   0   0  -5     =  0
     |-1   0   0   0   1   0   0     =  0
     | 0  -1  -1   0   0   1   0     =  0
     | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
     | 0   0   0   0   0   1   0     >= 0  # array size.
     | 0   0   0   0  -1   0 1335    >= 0
     | 0   0   0   0   0  -1 123     >= 0
 
     The pointer "*p" in alias set "5" and "7" is described as a union of
     polyhedron:
 
 
     | i   k   a  s0   1
     | 0   0   1   0  -5   =  0
     | 0   0   0   1   0   >= 0
 
     "or"
 
     | i   k   a  s0   1
     | 0   0   1   0  -7   =  0
     | 0   0   0   1   0   >= 0
 
     "*p" accesses all of the object allocated with 'malloc'.
 
     The scalar data access "m" is represented as an array with zero subscript
     dimensions.
 
     | i   j   k   a   1
     | 0   0   0  -1   15  = 0
 
     The difference between the graphite internal format for access data and
     the OpenSop format is in the order of columns.
     Instead of having:
 
     | i   j   k   a  s0  s1   1
     | 0   0   0   1   0   0  -5     =  0
     |-1   0   0   0   1   0   0     =  0
     | 0  -1  -1   0   0   1   0     =  0
     | 0   0   0   0   1   0   0     >= 0  # The last four lines describe the
     | 0   0   0   0   0   1   0     >= 0  # array size.
     | 0   0   0   0  -1   0 1335    >= 0
     | 0   0   0   0   0  -1 123     >= 0
 
     In OpenScop we have:
 
     | a  s0  s1   i   j   k   1
     | 1   0   0   0   0   0  -5     =  0
     | 0   1   0  -1   0   0   0     =  0
     | 0   0   1   0  -1  -1   0     =  0
     | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
     | 0   0   1   0   0   0   0     >= 0  # array size.
     | 0  -1   0   0   0   0 1335    >= 0
     | 0   0  -1   0   0   0 123     >= 0
 
     The OpenScop access function is printed as follows:
 
     | 1  # The number of disjunct components in a union of access functions.
     | R C O I L P  # Described bellow.
     | a  s0  s1   i   j   k   1
     | 1   0   0   0   0   0  -5     =  0
     | 0   1   0  -1   0   0   0     =  0
     | 0   0   1   0  -1  -1   0     =  0
     | 0   1   0   0   0   0   0     >= 0  # The last four lines describe the
     | 0   0   1   0   0   0   0     >= 0  # array size.
     | 0  -1   0   0   0   0 1335    >= 0
     | 0   0  -1   0   0   0 123     >= 0
 
     Where:
     - R: Number of rows.
     - C: Number of columns.
     - O: Number of output dimensions = alias set + number of subscripts.
     - I: Number of input dimensions (iterators).
     - L: Number of local (existentially quantified) dimensions.
     - P: Number of parameters.
 
     In the example, the vector "R C O I L P" is "7 7 3 2 0 1".  */
  isl_map *accesses;
  isl_set *subscript_sizes;
};
 
#define PDR_ID(PDR) (PDR->id)
#define PDR_NB_REFS(PDR) (PDR->nb_refs)
#define PDR_PBB(PDR) (PDR->pbb)
#define PDR_TYPE(PDR) (PDR->type)
#define PDR_ACCESSES(PDR) (NULL)
 
void new_poly_dr (poly_bb_p, gimple *, enum poly_dr_type,
                  isl_map *, isl_set *);
void debug_pdr (poly_dr_p);
void print_pdr (FILE *, poly_dr_p);
 
inline bool
pdr_read_p (poly_dr_p pdr)
{
  return PDR_TYPE (pdr) == PDR_READ;
}
 
/* Returns true when PDR is a "write".  */
 
inline bool
pdr_write_p (poly_dr_p pdr)
{
  return PDR_TYPE (pdr) == PDR_WRITE;
}
 
/* Returns true when PDR is a "may write".  */
 
inline bool
pdr_may_write_p (poly_dr_p pdr)
{
  return PDR_TYPE (pdr) == PDR_MAY_WRITE;
}
 
/* POLY_BB represents a blackbox in the polyhedral model.  */
 
struct poly_bb
{
  /* Pointer to a basic block or a statement in the compiler.  */
  gimple_poly_bb_p black_box;
 
  /* Pointer to the SCOP containing this PBB.  */
  scop_p scop;
 
  /* The iteration domain of this bb.  The layout of this polyhedron
     is I|G with I the iteration domain, G the context parameters.
 
     Example:
 
     for (i = a - 7*b + 8; i <= 3*a + 13*b + 20; i++)
       for (j = 2; j <= 2*i + 5; j++)
         for (k = 0; k <= 5; k++)
           S (i,j,k)
 
     Loop iterators: i, j, k
     Parameters: a, b
 
     | i >=  a -  7b +  8
     | i <= 3a + 13b + 20
     | j >= 2
     | j <= 2i + 5
     | k >= 0
     | k <= 5
 
     The number of variables in the DOMAIN may change and is not
     related to the number of loops in the original code.  */
  isl_set *domain;
  isl_set *iterators;
 
  /* The data references we access.  */
  vec<poly_dr_p> drs;
 
  /* The last basic block generated for this pbb.  */
  basic_block new_bb;
};
 
#define PBB_BLACK_BOX(PBB) ((gimple_poly_bb_p) PBB->black_box)
#define PBB_SCOP(PBB) (PBB->scop)
#define PBB_DRS(PBB) (PBB->drs)
 
extern poly_bb_p new_poly_bb (scop_p, gimple_poly_bb_p);
extern void print_pbb_domain (FILE *, poly_bb_p);
extern void print_pbb (FILE *, poly_bb_p);
extern void print_scop_context (FILE *, scop_p);
extern void print_scop (FILE *, scop_p);
extern void debug_pbb_domain (poly_bb_p);
extern void debug_pbb (poly_bb_p);
extern void print_pdrs (FILE *, poly_bb_p);
extern void debug_pdrs (poly_bb_p);
extern void debug_scop_context (scop_p);
extern void debug_scop (scop_p);
extern void print_scop_params (FILE *, scop_p);
extern void debug_scop_params (scop_p);
extern void print_iteration_domain (FILE *, poly_bb_p);
extern void print_iteration_domains (FILE *, scop_p);
extern void debug_iteration_domain (poly_bb_p);
extern void debug_iteration_domains (scop_p);
extern void print_isl_set (FILE *, isl_set *);
extern void print_isl_map (FILE *, isl_map *);
extern void print_isl_union_map (FILE *, isl_union_map *);
extern void print_isl_aff (FILE *, isl_aff *);
extern void print_isl_constraint (FILE *, isl_constraint *);
extern void print_isl_schedule (FILE *, isl_schedule *);
extern void debug_isl_schedule (isl_schedule *);
extern void print_isl_ast (FILE *, isl_ast_node *);
extern void debug_isl_ast (isl_ast_node *);
extern void debug_isl_set (isl_set *);
extern void debug_isl_map (isl_map *);
extern void debug_isl_union_map (isl_union_map *);
extern void debug_isl_aff (isl_aff *);
extern void debug_isl_constraint (isl_constraint *);
extern void debug_gmp_value (mpz_t);
extern void debug_scop_pbb (scop_p scop, int i);
extern void print_schedule_ast (FILE *, __isl_keep isl_schedule *, scop_p);
extern void debug_schedule_ast (__isl_keep isl_schedule *, scop_p);
 
/* The basic block of the PBB.  */
 
inline basic_block
pbb_bb (poly_bb_p pbb)
{
  return GBB_BB (PBB_BLACK_BOX (pbb));
}
 
inline int
pbb_index (poly_bb_p pbb)
{
  return pbb_bb (pbb)->index;
}
 
/* The loop of the PBB.  */
 
inline loop_p
pbb_loop (poly_bb_p pbb)
{
  return gbb_loop (PBB_BLACK_BOX (pbb));
}
 
/* The scop that contains the PDR.  */
 
inline scop_p
pdr_scop (poly_dr_p pdr)
{
  return PBB_SCOP (PDR_PBB (pdr));
}
 
/* Set black box of PBB to BLACKBOX.  */
 
inline void
pbb_set_black_box (poly_bb_p pbb, gimple_poly_bb_p black_box)
{
  pbb->black_box = black_box;
}
 
/* A helper structure to keep track of data references, polyhedral BBs, and
   alias sets.  */
 
struct dr_info
{
  enum {
    invalid_alias_set = -1
  };
  /* The data reference.  */
  data_reference_p dr;
 
  /* The polyhedral BB containing this DR.  */
  poly_bb_p pbb;
 
  /* ALIAS_SET is the SCC number assigned by a graph_dfs of the alias graph.
     -1 is an invalid alias set.  */
  int alias_set;
 
  /* Construct a DR_INFO from a data reference DR, an ALIAS_SET, and a PBB.  */
  dr_info (data_reference_p dr, poly_bb_p pbb,
           int alias_set = invalid_alias_set)
    : dr (dr), pbb (pbb), alias_set (alias_set) {}
};
 
/* A SCOP is a Static Control Part of the program, simple enough to be
   represented in polyhedral form.  */
struct scop
{
  /* A SCOP is defined as a SESE region.  */
  sese_info_p scop_info;
 
  /* Number of parameters in SCoP.  */
  graphite_dim_t nb_params;
 
  /* The maximum alias set as assigned to drs by build_alias_sets.  */
  unsigned max_alias_set;
 
  /* All the basic blocks in this scop that contain memory references
     and that will be represented as statements in the polyhedral
     representation.  */
  vec<poly_bb_p> pbbs;
 
  /* All the data references in this scop.  */
  vec<dr_info> drs;
 
  /* The context describes known restrictions concerning the parameters
     and relations in between the parameters.
 
  void f (int8_t a, uint_16_t b) {
    c = 2 a + b;
    ...
  }
 
  Here we can add these restrictions to the context:
 
  -128 >= a >= 127
     0 >= b >= 65,535
     c = 2a + b  */
  isl_set *param_context;
 
  /* The context used internally by isl.  */
  isl_ctx *isl_context;
 
  /* SCoP original schedule.  */
  isl_schedule *original_schedule;
 
  /* SCoP transformed schedule.  */
  isl_schedule *transformed_schedule;
 
  /* The data dependence relation among the data references in this scop.  */
  isl_union_map *dependence;
};
 
extern scop_p new_scop (edge, edge);
extern void free_scop (scop_p);
extern gimple_poly_bb_p new_gimple_poly_bb (basic_block, vec<data_reference_p>,
                                            vec<scalar_use>, vec<tree>);
extern bool apply_poly_transforms (scop_p);
 
/* Set the region of SCOP to REGION.  */
 
inline void
scop_set_region (scop_p scop, sese_info_p region)
{
  scop->scop_info = region;
}
 
/* Returns the number of parameters for SCOP.  */
 
inline graphite_dim_t
scop_nb_params (scop_p scop)
{
  return scop->nb_params;
}
 
/* Set the number of params of SCOP to NB_PARAMS.  */
 
inline void
scop_set_nb_params (scop_p scop, graphite_dim_t nb_params)
{
  scop->nb_params = nb_params;
}
 
extern void scop_get_dependences (scop_p scop);
 
bool
carries_deps (__isl_keep isl_union_map *schedule,
              __isl_keep isl_union_map *deps,
              int depth);
 
extern bool build_poly_scop (scop_p);
extern bool graphite_regenerate_ast_isl (scop_p);
extern void build_scops (vec<scop_p> *);
extern tree cached_scalar_evolution_in_region (const sese_l &, loop_p, tree);
extern void dot_all_sese (FILE *, vec<sese_l> &);
extern void dot_sese (sese_l &);
extern void dot_cfg ();
 
#endif