Exemple #1
0
static bool
copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
{
  int p1, p2, p3;
  tree root1, root2;
  tree rep1, rep2;
  bool ign1, ign2, abnorm;

  gcc_assert (TREE_CODE (var1) == SSA_NAME);
  gcc_assert (TREE_CODE (var2) == SSA_NAME);

  register_ssa_partition (map, var1);
  register_ssa_partition (map, var2);

  p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1));
  p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2));

  if (debug)
    {
      fprintf (debug, "Try : ");
      print_generic_expr (debug, var1, TDF_SLIM);
      fprintf (debug, "(P%d) & ", p1);
      print_generic_expr (debug, var2, TDF_SLIM);
      fprintf (debug, "(P%d)", p2);
    }

  gcc_assert (p1 != NO_PARTITION);
  gcc_assert (p2 != NO_PARTITION);

  if (p1 == p2)
    {
      if (debug)
	fprintf (debug, " : Already coalesced.\n");
      return false;
    }

  rep1 = partition_to_var (map, p1);
  rep2 = partition_to_var (map, p2);
  root1 = SSA_NAME_VAR (rep1);
  root2 = SSA_NAME_VAR (rep2);
  if (!root1 && !root2)
    return false;

  /* Don't coalesce if one of the variables occurs in an abnormal PHI.  */
  abnorm = (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep1)
	    || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep2));
  if (abnorm)
    {
      if (debug)
	fprintf (debug, " : Abnormal PHI barrier.  No coalesce.\n");
      return false;
    }

  /* Partitions already have the same root, simply merge them.  */
  if (root1 == root2)
    {
      p1 = partition_union (map->var_partition, p1, p2);
      if (debug)
	fprintf (debug, " : Same root, coalesced --> P%d.\n", p1);
      return false;
    }

  /* Never attempt to coalesce 2 different parameters.  */
  if ((root1 && TREE_CODE (root1) == PARM_DECL)
      && (root2 && TREE_CODE (root2) == PARM_DECL))
    {
      if (debug)
        fprintf (debug, " : 2 different PARM_DECLS. No coalesce.\n");
      return false;
    }

  if ((root1 && TREE_CODE (root1) == RESULT_DECL)
      != (root2 && TREE_CODE (root2) == RESULT_DECL))
    {
      if (debug)
        fprintf (debug, " : One root a RESULT_DECL. No coalesce.\n");
      return false;
    }

  ign1 = !root1 || (TREE_CODE (root1) == VAR_DECL && DECL_IGNORED_P (root1));
  ign2 = !root2 || (TREE_CODE (root2) == VAR_DECL && DECL_IGNORED_P (root2));

  /* Refrain from coalescing user variables, if requested.  */
  if (!ign1 && !ign2)
    {
      if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root2))
	ign2 = true;
      else if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root1))
	ign1 = true;
      else if (flag_ssa_coalesce_vars != 2)
	{
	  if (debug)
	    fprintf (debug, " : 2 different USER vars. No coalesce.\n");
	  return false;
	}
      else
	ign2 = true;
    }

  /* If both values have default defs, we can't coalesce.  If only one has a
     tag, make sure that variable is the new root partition.  */
  if (root1 && ssa_default_def (cfun, root1))
    {
      if (root2 && ssa_default_def (cfun, root2))
	{
	  if (debug)
	    fprintf (debug, " : 2 default defs. No coalesce.\n");
	  return false;
	}
      else
        {
	  ign2 = true;
	  ign1 = false;
	}
    }
  else if (root2 && ssa_default_def (cfun, root2))
    {
      ign1 = true;
      ign2 = false;
    }

  /* Do not coalesce if we cannot assign a symbol to the partition.  */
  if (!(!ign2 && root2)
      && !(!ign1 && root1))
    {
      if (debug)
	fprintf (debug, " : Choosen variable has no root.  No coalesce.\n");
      return false;
    }

  /* Don't coalesce if the new chosen root variable would be read-only.
     If both ign1 && ign2, then the root var of the larger partition
     wins, so reject in that case if any of the root vars is TREE_READONLY.
     Otherwise reject only if the root var, on which replace_ssa_name_symbol
     will be called below, is readonly.  */
  if (((root1 && TREE_READONLY (root1)) && ign2)
      || ((root2 && TREE_READONLY (root2)) && ign1))
    {
      if (debug)
	fprintf (debug, " : Readonly variable.  No coalesce.\n");
      return false;
    }

  /* Don't coalesce if the two variables aren't type compatible .  */
  if (!types_compatible_p (TREE_TYPE (var1), TREE_TYPE (var2))
      /* There is a disconnect between the middle-end type-system and
         VRP, avoid coalescing enum types with different bounds.  */
      || ((TREE_CODE (TREE_TYPE (var1)) == ENUMERAL_TYPE
	   || TREE_CODE (TREE_TYPE (var2)) == ENUMERAL_TYPE)
	  && TREE_TYPE (var1) != TREE_TYPE (var2)))
    {
      if (debug)
	fprintf (debug, " : Incompatible types.  No coalesce.\n");
      return false;
    }

  /* Merge the two partitions.  */
  p3 = partition_union (map->var_partition, p1, p2);

  /* Set the root variable of the partition to the better choice, if there is
     one.  */
  if (!ign2 && root2)
    replace_ssa_name_symbol (partition_to_var (map, p3), root2);
  else if (!ign1 && root1)
    replace_ssa_name_symbol (partition_to_var (map, p3), root1);
  else
    gcc_unreachable ();

  if (debug)
    {
      fprintf (debug, " --> P%d ", p3);
      print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)),
			  TDF_SLIM);
      fprintf (debug, "\n");
    }
  return true;
}
static bool
copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
{
  int p1, p2, p3;
  tree root1, root2;
  tree rep1, rep2;
  bool ign1, ign2, abnorm;

  gcc_assert (TREE_CODE (var1) == SSA_NAME);
  gcc_assert (TREE_CODE (var2) == SSA_NAME);

  register_ssa_partition (map, var1);
  register_ssa_partition (map, var2);

  p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1));
  p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2));

  if (debug)
    {
      fprintf (debug, "Try : ");
      print_generic_expr (debug, var1, TDF_SLIM);
      fprintf (debug, "(P%d) & ", p1);
      print_generic_expr (debug, var2, TDF_SLIM);
      fprintf (debug, "(P%d)", p2);
    }

  gcc_assert (p1 != NO_PARTITION);
  gcc_assert (p2 != NO_PARTITION);

  rep1 = partition_to_var (map, p1);
  rep2 = partition_to_var (map, p2);
  root1 = SSA_NAME_VAR (rep1);
  root2 = SSA_NAME_VAR (rep2);

  if (p1 == p2)
    {
      if (debug)
	fprintf (debug, " : Already coalesced.\n");
      return false;
    }

  /* Don't coalesce if one of the variables occurs in an abnormal PHI.  */
  abnorm = (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep1)
	    || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep2));
  if (abnorm)
    {
      if (debug)
	fprintf (debug, " : Abnormal PHI barrier.  No coalesce.\n");
      return false;
    }

  /* Partitions already have the same root, simply merge them.  */
  if (root1 == root2)
    {
      p1 = partition_union (map->var_partition, p1, p2);
      if (debug)
	fprintf (debug, " : Same root, coalesced --> P%d.\n", p1);
      return false;
    }

  /* Never attempt to coalesce 2 difference parameters.  */
  if (TREE_CODE (root1) == PARM_DECL && TREE_CODE (root2) == PARM_DECL)
    {
      if (debug)
        fprintf (debug, " : 2 different PARM_DECLS. No coalesce.\n");
      return false;
    }

  if ((TREE_CODE (root1) == RESULT_DECL) != (TREE_CODE (root2) == RESULT_DECL))
    {
      if (debug)
        fprintf (debug, " : One root a RESULT_DECL. No coalesce.\n");
      return false;
    }

  ign1 = TREE_CODE (root1) == VAR_DECL && DECL_IGNORED_P (root1);
  ign2 = TREE_CODE (root2) == VAR_DECL && DECL_IGNORED_P (root2);

  /* Never attempt to coalesce 2 user variables unless one is an inline
     variable.  */
  if (!ign1 && !ign2)
    {
      if (DECL_FROM_INLINE (root2))
        ign2 = true;
      else if (DECL_FROM_INLINE (root1))
	ign1 = true;
      else
	{
	  if (debug)
	    fprintf (debug, " : 2 different USER vars. No coalesce.\n");
	  return false;
	}
    }

  /* If both values have default defs, we can't coalesce.  If only one has a
     tag, make sure that variable is the new root partition.  */
  if (gimple_default_def (cfun, root1))
    {
      if (gimple_default_def (cfun, root2))
	{
	  if (debug)
	    fprintf (debug, " : 2 default defs. No coalesce.\n");
	  return false;
	}
      else
        {
	  ign2 = true;
	  ign1 = false;
	}
    }
  else if (gimple_default_def (cfun, root2))
    {
      ign1 = true;
      ign2 = false;
    }

  /* Don't coalesce if the two variables aren't type compatible.  */
  if (!types_compatible_p (TREE_TYPE (root1), TREE_TYPE (root2)))
    {
      if (debug)
	fprintf (debug, " : Incompatible types.  No coalesce.\n");
      return false;
    }

  /* Merge the two partitions.  */
  p3 = partition_union (map->var_partition, p1, p2);

  /* Set the root variable of the partition to the better choice, if there is
     one.  */
  if (!ign2)
    replace_ssa_name_symbol (partition_to_var (map, p3), root2);
  else if (!ign1)
    replace_ssa_name_symbol (partition_to_var (map, p3), root1);

  if (debug)
    {
      fprintf (debug, " --> P%d ", p3);
      print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)),
			  TDF_SLIM);
      fprintf (debug, "\n");
    }
  return true;
}