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/* IRA conflict builder.

   Copyright (C) 2006, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Contributed by Vladimir Makarov <vmakarov@redhat.com>.

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/>.  */

#include "config.h"

#include "system.h"

#include "coretypes.h"

#include "tm.h"

#include "regs.h"

#include "rtl.h"

#include "tm_p.h"

#include "target.h"

#include "flags.h"

#include "hard-reg-set.h"

#include "basic-block.h"

#include "insn-config.h"

#include "recog.h"

#include "diagnostic-core.h"

#include "params.h"

#include "df.h"

#include "sparseset.h"

#include "ira-int.h"

#include "addresses.h"

/* This file contains code responsible for allocno conflict creation,

   allocno copy creation and allocno info accumulation on upper level

   regions.  */

/* ira_allocnos_num array of arrays of bits, recording whether two

   allocno's conflict (can't go in the same hardware register).

   Some arrays will be used as conflict bit vector of the

   corresponding allocnos see function build_object_conflicts.  */

static IRA_INT_TYPE **conflicts;

/* Macro to test a conflict of C1 and C2 in `conflicts'.  */

#define OBJECTS_CONFLICT_P(C1, C2)                                      \

  (OBJECT_MIN (C1) <= OBJECT_CONFLICT_ID (C2)                           \

   && OBJECT_CONFLICT_ID (C2) <= OBJECT_MAX (C1)                        \

   && TEST_MINMAX_SET_BIT (conflicts[OBJECT_CONFLICT_ID (C1)],          \

                           OBJECT_CONFLICT_ID (C2),                     \

                           OBJECT_MIN (C1), OBJECT_MAX (C1)))

/* Record a conflict between objects OBJ1 and OBJ2.  If necessary,

   canonicalize the conflict by recording it for lower-order subobjects

   of the corresponding allocnos. */

static void

record_object_conflict (ira_object_t obj1, ira_object_t obj2)

{

  ira_allocno_t a1 = OBJECT_ALLOCNO (obj1);

  ira_allocno_t a2 = OBJECT_ALLOCNO (obj2);

  int w1 = OBJECT_SUBWORD (obj1);

  int w2 = OBJECT_SUBWORD (obj2);

  int id1, id2;

  /* Canonicalize the conflict.  If two identically-numbered words

     conflict, always record this as a conflict between words 0.  That

     is the only information we need, and it is easier to test for if

     it is collected in each allocno's lowest-order object.  */

  if (w1 == w2 && w1 > 0)

    {

      obj1 = ALLOCNO_OBJECT (a1, 0);

      obj2 = ALLOCNO_OBJECT (a2, 0);

    }

  id1 = OBJECT_CONFLICT_ID (obj1);

  id2 = OBJECT_CONFLICT_ID (obj2);

  SET_MINMAX_SET_BIT (conflicts[id1], id2, OBJECT_MIN (obj1),

                      OBJECT_MAX (obj1));

  SET_MINMAX_SET_BIT (conflicts[id2], id1, OBJECT_MIN (obj2),

                      OBJECT_MAX (obj2));

}

/* Build allocno conflict table by processing allocno live ranges.

   Return true if the table was built.  The table is not built if it

   is too big.  */

static bool

build_conflict_bit_table (void)

{

  int i;

  unsigned int j;

  enum reg_class aclass;

  int object_set_words, allocated_words_num, conflict_bit_vec_words_num;

  live_range_t r;

  ira_allocno_t allocno;

  ira_allocno_iterator ai;

  sparseset objects_live;

  ira_object_t obj;

  ira_allocno_object_iterator aoi;

  allocated_words_num = 0;

  FOR_EACH_ALLOCNO (allocno, ai)

    FOR_EACH_ALLOCNO_OBJECT (allocno, obj, aoi)

      {

        if (OBJECT_MAX (obj) < OBJECT_MIN (obj))

          continue;

        conflict_bit_vec_words_num

          = ((OBJECT_MAX (obj) - OBJECT_MIN (obj) + IRA_INT_BITS)

             / IRA_INT_BITS);

        allocated_words_num += conflict_bit_vec_words_num;

        if ((unsigned HOST_WIDEST_INT) allocated_words_num * sizeof (IRA_INT_TYPE)

            > (unsigned HOST_WIDEST_INT) IRA_MAX_CONFLICT_TABLE_SIZE * 1024 * 1024)

          {

            if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL)

              fprintf

                (ira_dump_file,

                 "+++Conflict table will be too big(>%dMB) -- don't use it\n",

                 IRA_MAX_CONFLICT_TABLE_SIZE);

            return false;

          }

      }

  conflicts = (IRA_INT_TYPE **) ira_allocate (sizeof (IRA_INT_TYPE *)

                                              * ira_objects_num);

  allocated_words_num = 0;

  FOR_EACH_ALLOCNO (allocno, ai)

    FOR_EACH_ALLOCNO_OBJECT (allocno, obj, aoi)

      {

        int id = OBJECT_CONFLICT_ID (obj);

        if (OBJECT_MAX (obj) < OBJECT_MIN (obj))

          {

            conflicts[id] = NULL;

            continue;

          }

        conflict_bit_vec_words_num

          = ((OBJECT_MAX (obj) - OBJECT_MIN (obj) + IRA_INT_BITS)

             / IRA_INT_BITS);

        allocated_words_num += conflict_bit_vec_words_num;

        conflicts[id]

          = (IRA_INT_TYPE *) ira_allocate (sizeof (IRA_INT_TYPE)

                                           * conflict_bit_vec_words_num);

        memset (conflicts[id], 0,

                sizeof (IRA_INT_TYPE) * conflict_bit_vec_words_num);

      }

  object_set_words = (ira_objects_num + IRA_INT_BITS - 1) / IRA_INT_BITS;

  if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL)

    fprintf

      (ira_dump_file,

       "+++Allocating %ld bytes for conflict table (uncompressed size %ld)\n",

       (long) allocated_words_num * sizeof (IRA_INT_TYPE),

       (long) object_set_words * ira_objects_num * sizeof (IRA_INT_TYPE));

  objects_live = sparseset_alloc (ira_objects_num);

  for (i = 0; i < ira_max_point; i++)

    {

      for (r = ira_start_point_ranges[i]; r != NULL; r = r->start_next)

        {

          ira_object_t obj = r->object;

          ira_allocno_t allocno = OBJECT_ALLOCNO (obj);

          int id = OBJECT_CONFLICT_ID (obj);

          gcc_assert (id < ira_objects_num);

          aclass = ALLOCNO_CLASS (allocno);

          sparseset_set_bit (objects_live, id);

          EXECUTE_IF_SET_IN_SPARSESET (objects_live, j)

            {

              ira_object_t live_obj = ira_object_id_map[j];

              ira_allocno_t live_a = OBJECT_ALLOCNO (live_obj);

              enum reg_class live_aclass = ALLOCNO_CLASS (live_a);

              if (ira_reg_classes_intersect_p[aclass][live_aclass]

                  /* Don't set up conflict for the allocno with itself.  */

                  && live_a != allocno)

                {

                  record_object_conflict (obj, live_obj);

                }

            }

        }

      for (r = ira_finish_point_ranges[i]; r != NULL; r = r->finish_next)

        sparseset_clear_bit (objects_live, OBJECT_CONFLICT_ID (r->object));

    }

  sparseset_free (objects_live);

  return true;

}

/* Return true iff allocnos A1 and A2 cannot be allocated to the same

   register due to conflicts.  */

static bool

allocnos_conflict_for_copy_p (ira_allocno_t a1, ira_allocno_t a2)

{

  /* Due to the fact that we canonicalize conflicts (see

     record_object_conflict), we only need to test for conflicts of

     the lowest order words.  */

  ira_object_t obj1 = ALLOCNO_OBJECT (a1, 0);

  ira_object_t obj2 = ALLOCNO_OBJECT (a2, 0);

  return OBJECTS_CONFLICT_P (obj1, obj2);

}

/* Return TRUE if the operand constraint STR is commutative.  */

static bool

commutative_constraint_p (const char *str)

{

  int curr_alt, c;

  bool ignore_p;

  for (ignore_p = false, curr_alt = 0;;)

    {

      c = *str;

      if (c == '\0')

        break;

      str += CONSTRAINT_LEN (c, str);

      if (c == '#' || !recog_data.alternative_enabled_p[curr_alt])

        ignore_p = true;

      else if (c == ',')

        {

          curr_alt++;

          ignore_p = false;

        }

      else if (! ignore_p)

        {

          /* Usually `%' is the first constraint character but the

             documentation does not require this.  */

          if (c == '%')

            return true;

        }

    }

  return false;

}

/* Return the number of the operand which should be the same in any

   case as operand with number OP_NUM (or negative value if there is

   no such operand).  If USE_COMMUT_OP_P is TRUE, the function makes

   temporarily commutative operand exchange before this.  The function

   takes only really possible alternatives into consideration.  */

static int

get_dup_num (int op_num, bool use_commut_op_p)

{

  int curr_alt, c, original, dup;

  bool ignore_p, commut_op_used_p;

  const char *str;

  rtx op;

  if (op_num < 0 || recog_data.n_alternatives == 0)

    return -1;

  op = recog_data.operand[op_num];

  commut_op_used_p = true;

  if (use_commut_op_p)

    {

      if (commutative_constraint_p (recog_data.constraints[op_num]))

        op_num++;

      else if (op_num > 0 && commutative_constraint_p (recog_data.constraints

                                                       [op_num - 1]))

        op_num--;

      else

        commut_op_used_p = false;

    }

  str = recog_data.constraints[op_num];

  for (ignore_p = false, original = -1, curr_alt = 0;;)

    {

      c = *str;

      if (c == '\0')

        break;

      if (c == '#' || !recog_data.alternative_enabled_p[curr_alt])

        ignore_p = true;

      else if (c == ',')

        {

          curr_alt++;

          ignore_p = false;

        }

      else if (! ignore_p)

        switch (c)

          {

          case 'X':

            return -1;

          case 'm':

          case 'o':

            /* Accept a register which might be placed in memory.  */

            return -1;

            break;

          case 'V':

          case '<':

          case '>':

            break;

          case 'p':

            if (address_operand (op, VOIDmode))

              return -1;

            break;

          case 'g':

            return -1;

          case 'r':

          case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':

          case 'h': case 'j': case 'k': case 'l':

          case 'q': case 't': case 'u':

          case 'v': case 'w': case 'x': case 'y': case 'z':

          case 'A': case 'B': case 'C': case 'D':

          case 'Q': case 'R': case 'S': case 'T': case 'U':

          case 'W': case 'Y': case 'Z':

            {

              enum reg_class cl;

              cl = (c == 'r'

                    ? GENERAL_REGS : REG_CLASS_FROM_CONSTRAINT (c, str));

              if (cl != NO_REGS)

                return -1;

#ifdef EXTRA_CONSTRAINT_STR

              else if (EXTRA_CONSTRAINT_STR (op, c, str))

                return -1;

#endif

              break;

            }

          case '0': case '1': case '2': case '3': case '4':

          case '5': case '6': case '7': case '8': case '9':

            if (original != -1 && original != c)

              return -1;

            original = c;

            break;

          }

      str += CONSTRAINT_LEN (c, str);

    }

  if (original == -1)

    return -1;

  dup = original - '0';

  if (use_commut_op_p)

    {

      if (commutative_constraint_p (recog_data.constraints[dup]))

        dup++;

      else if (dup > 0

               && commutative_constraint_p (recog_data.constraints[dup -1]))

        dup--;

      else if (! commut_op_used_p)

        return -1;

    }

  return dup;

}

/* Check that X is REG or SUBREG of REG.  */

#define REG_SUBREG_P(x)                                                 \

   (REG_P (x) || (GET_CODE (x) == SUBREG && REG_P (SUBREG_REG (x))))

/* Return X if X is a REG, otherwise it should be SUBREG of REG and

   the function returns the reg in this case.  *OFFSET will be set to

static rtx

go_through_subreg (rtx x, int *offset)

{

  rtx reg;

  *offset = 0;

  if (REG_P (x))

    return x;

  ira_assert (GET_CODE (x) == SUBREG);

  reg = SUBREG_REG (x);

  ira_assert (REG_P (reg));

  if (REGNO (reg) < FIRST_PSEUDO_REGISTER)

    *offset = subreg_regno_offset (REGNO (reg), GET_MODE (reg),

                                   SUBREG_BYTE (x), GET_MODE (x));

  else

    *offset = (SUBREG_BYTE (x) / REGMODE_NATURAL_SIZE (GET_MODE (x)));

  return reg;

}

/* Process registers REG1 and REG2 in move INSN with execution

   frequency FREQ.  The function also processes the registers in a

   potential move insn (INSN == NULL in this case) with frequency

   FREQ.  The function can modify hard register costs of the

   corresponding allocnos or create a copy involving the corresponding

   allocnos.  The function does nothing if the both registers are hard

   registers.  When nothing is changed, the function returns

   FALSE.  */

static bool

process_regs_for_copy (rtx reg1, rtx reg2, bool constraint_p,

                       rtx insn, int freq)

{

  int allocno_preferenced_hard_regno, cost, index, offset1, offset2;

  bool only_regs_p;

  ira_allocno_t a;

  reg_class_t rclass, aclass;

  enum machine_mode mode;

  ira_copy_t cp;

  gcc_assert (REG_SUBREG_P (reg1) && REG_SUBREG_P (reg2));

  only_regs_p = REG_P (reg1) && REG_P (reg2);

  reg1 = go_through_subreg (reg1, &offset1);

  reg2 = go_through_subreg (reg2, &offset2);

  /* Set up hard regno preferenced by allocno.  If allocno gets the

     hard regno the copy (or potential move) insn will be removed.  */

  if (HARD_REGISTER_P (reg1))

    {

      if (HARD_REGISTER_P (reg2))

        return false;

      allocno_preferenced_hard_regno = REGNO (reg1) + offset1 - offset2;

      a = ira_curr_regno_allocno_map[REGNO (reg2)];

    }

  else if (HARD_REGISTER_P (reg2))

    {

      allocno_preferenced_hard_regno = REGNO (reg2) + offset2 - offset1;

      a = ira_curr_regno_allocno_map[REGNO (reg1)];

    }

  else

    {

      ira_allocno_t a1 = ira_curr_regno_allocno_map[REGNO (reg1)];

      ira_allocno_t a2 = ira_curr_regno_allocno_map[REGNO (reg2)];

      if (!allocnos_conflict_for_copy_p (a1, a2) && offset1 == offset2)

        {

          cp = ira_add_allocno_copy (a1, a2, freq, constraint_p, insn,

                                     ira_curr_loop_tree_node);

          bitmap_set_bit (ira_curr_loop_tree_node->local_copies, cp->num);

          return true;

        }

      else

        return false;

    }

  if (! IN_RANGE (allocno_preferenced_hard_regno,

                  0, FIRST_PSEUDO_REGISTER - 1))

    /* Can not be tied.  */

    return false;

  rclass = REGNO_REG_CLASS (allocno_preferenced_hard_regno);

  mode = ALLOCNO_MODE (a);

  aclass = ALLOCNO_CLASS (a);

  if (only_regs_p && insn != NULL_RTX

      && reg_class_size[rclass] <= ira_reg_class_max_nregs [rclass][mode])

    /* It is already taken into account in ira-costs.c.  */

    return false;

  index = ira_class_hard_reg_index[aclass][allocno_preferenced_hard_regno];

  if (index < 0)

    /* Can not be tied.  It is not in the allocno class.  */

    return false;

  ira_init_register_move_cost_if_necessary (mode);

  if (HARD_REGISTER_P (reg1))

    cost = ira_register_move_cost[mode][aclass][rclass] * freq;

  else

    cost = ira_register_move_cost[mode][rclass][aclass] * freq;

  do

    {

      ira_allocate_and_set_costs

        (&ALLOCNO_HARD_REG_COSTS (a), aclass,

         ALLOCNO_CLASS_COST (a));

      ira_allocate_and_set_costs

        (&ALLOCNO_CONFLICT_HARD_REG_COSTS (a), aclass, 0);

      ALLOCNO_HARD_REG_COSTS (a)[index] -= cost;

      ALLOCNO_CONFLICT_HARD_REG_COSTS (a)[index] -= cost;

      if (ALLOCNO_HARD_REG_COSTS (a)[index] < ALLOCNO_CLASS_COST (a))

        ALLOCNO_CLASS_COST (a) = ALLOCNO_HARD_REG_COSTS (a)[index];

      a = ira_parent_or_cap_allocno (a);

    }

  while (a != NULL);

  return true;

}

/* Process all of the output registers of the current insn which are

   not bound (BOUND_P) and the input register REG (its operand number

   OP_NUM) which dies in the insn as if there were a move insn between

   them with frequency FREQ.  */

static void

process_reg_shuffles (rtx reg, int op_num, int freq, bool *bound_p)

{

  int i;

  rtx another_reg;

  gcc_assert (REG_SUBREG_P (reg));

  for (i = 0; i < recog_data.n_operands; i++)

    {

      another_reg = recog_data.operand[i];

      if (!REG_SUBREG_P (another_reg) || op_num == i

          || recog_data.operand_type[i] != OP_OUT

          || bound_p[i])

        continue;

      process_regs_for_copy (reg, another_reg, false, NULL_RTX, freq);

    }

}

/* Process INSN and create allocno copies if necessary.  For example,

   it might be because INSN is a pseudo-register move or INSN is two

   operand insn.  */

static void

add_insn_allocno_copies (rtx insn)

{

  rtx set, operand, dup;

  const char *str;

  bool commut_p, bound_p[MAX_RECOG_OPERANDS];

  int i, j, n, freq;

  freq = REG_FREQ_FROM_BB (BLOCK_FOR_INSN (insn));

  if (freq == 0)

    freq = 1;

  if ((set = single_set (insn)) != NULL_RTX

      && REG_SUBREG_P (SET_DEST (set)) && REG_SUBREG_P (SET_SRC (set))

      && ! side_effects_p (set)

      && find_reg_note (insn, REG_DEAD,

                        REG_P (SET_SRC (set))

                        ? SET_SRC (set)

                        : SUBREG_REG (SET_SRC (set))) != NULL_RTX)

    {

      process_regs_for_copy (SET_DEST (set), SET_SRC (set),

                             false, insn, freq);

      return;

    }

  /* Fast check of possibility of constraint or shuffle copies.  If

     there are no dead registers, there will be no such copies.  */

  if (! find_reg_note (insn, REG_DEAD, NULL_RTX))

    return;

  extract_insn (insn);

  for (i = 0; i < recog_data.n_operands; i++)

    bound_p[i] = false;

  for (i = 0; i < recog_data.n_operands; i++)

    {

      operand = recog_data.operand[i];

      if (! REG_SUBREG_P (operand))

        continue;

      str = recog_data.constraints[i];

      while (*str == ' ' || *str == '\t')

        str++;

      for (j = 0, commut_p = false; j < 2; j++, commut_p = true)

        if ((n = get_dup_num (i, commut_p)) >= 0)

          {

            bound_p[n] = true;

            dup = recog_data.operand[n];

            if (REG_SUBREG_P (dup)

                && find_reg_note (insn, REG_DEAD,

                                  REG_P (operand)

                                  ? operand

                                  : SUBREG_REG (operand)) != NULL_RTX)

              process_regs_for_copy (operand, dup, true, NULL_RTX, freq);

          }

    }

  for (i = 0; i < recog_data.n_operands; i++)

    {

      operand = recog_data.operand[i];

      if (REG_SUBREG_P (operand)

          && find_reg_note (insn, REG_DEAD,

                            REG_P (operand)

                            ? operand : SUBREG_REG (operand)) != NULL_RTX)

        /* If an operand dies, prefer its hard register for the output

           operands by decreasing the hard register cost or creating

           the corresponding allocno copies.  The cost will not

           correspond to a real move insn cost, so make the frequency

           smaller.  */

        process_reg_shuffles (operand, i, freq < 8 ? 1 : freq / 8, bound_p);

    }

}

/* Add copies originated from BB given by LOOP_TREE_NODE.  */

static void

add_copies (ira_loop_tree_node_t loop_tree_node)

{

  basic_block bb;

  rtx insn;

  bb = loop_tree_node->bb;

  if (bb == NULL)

    return;

  FOR_BB_INSNS (bb, insn)

    if (NONDEBUG_INSN_P (insn))

      add_insn_allocno_copies (insn);

}

/* Propagate copies the corresponding allocnos on upper loop tree

   level.  */

static void

propagate_copies (void)

{

  ira_copy_t cp;

  ira_copy_iterator ci;

  ira_allocno_t a1, a2, parent_a1, parent_a2;

  FOR_EACH_COPY (cp, ci)

    {

      a1 = cp->first;

      a2 = cp->second;

      if (ALLOCNO_LOOP_TREE_NODE (a1) == ira_loop_tree_root)

        continue;

      ira_assert ((ALLOCNO_LOOP_TREE_NODE (a2) != ira_loop_tree_root));

      parent_a1 = ira_parent_or_cap_allocno (a1);

      parent_a2 = ira_parent_or_cap_allocno (a2);

      ira_assert (parent_a1 != NULL && parent_a2 != NULL);

      if (! allocnos_conflict_for_copy_p (parent_a1, parent_a2))

        ira_add_allocno_copy (parent_a1, parent_a2, cp->freq,

                              cp->constraint_p, cp->insn, cp->loop_tree_node);

    }

}

/* Array used to collect all conflict allocnos for given allocno.  */

static ira_object_t *collected_conflict_objects;

/* Build conflict vectors or bit conflict vectors (whatever is more

   profitable) for object OBJ from the conflict table.  */

static void

build_object_conflicts (ira_object_t obj)

{

  int i, px, parent_num;

  ira_allocno_t parent_a, another_parent_a;

  ira_object_t parent_obj;

  ira_allocno_t a = OBJECT_ALLOCNO (obj);

  IRA_INT_TYPE *object_conflicts;

  minmax_set_iterator asi;

  int parent_min, parent_max ATTRIBUTE_UNUSED;

  object_conflicts = conflicts[OBJECT_CONFLICT_ID (obj)];

  px = 0;

  FOR_EACH_BIT_IN_MINMAX_SET (object_conflicts,

                              OBJECT_MIN (obj), OBJECT_MAX (obj), i, asi)

    {

      ira_object_t another_obj = ira_object_id_map[i];

      ira_allocno_t another_a = OBJECT_ALLOCNO (obj);

      ira_assert (ira_reg_classes_intersect_p

                  [ALLOCNO_CLASS (a)][ALLOCNO_CLASS (another_a)]);

      collected_conflict_objects[px++] = another_obj;

    }

  if (ira_conflict_vector_profitable_p (obj, px))

    {

      ira_object_t *vec;

      ira_allocate_conflict_vec (obj, px);

      vec = OBJECT_CONFLICT_VEC (obj);

      memcpy (vec, collected_conflict_objects, sizeof (ira_object_t) * px);

      vec[px] = NULL;

      OBJECT_NUM_CONFLICTS (obj) = px;

    }

  else

    {

      int conflict_bit_vec_words_num;

      OBJECT_CONFLICT_ARRAY (obj) = object_conflicts;

      if (OBJECT_MAX (obj) < OBJECT_MIN (obj))

        conflict_bit_vec_words_num = 0;

      else

        conflict_bit_vec_words_num

          = ((OBJECT_MAX (obj) - OBJECT_MIN (obj) + IRA_INT_BITS)

             / IRA_INT_BITS);