Ejemplo n.º 1
0
void
add_phi_arg (gimple phi, tree def, edge e)
{
  basic_block bb = e->dest;

  gcc_assert (bb == gimple_bb (phi));

  /* We resize PHI nodes upon edge creation.  We should always have
     enough room at this point.  */
  gcc_assert (gimple_phi_num_args (phi) <= gimple_phi_capacity (phi));

  /* We resize PHI nodes upon edge creation.  We should always have
     enough room at this point.  */
  gcc_assert (e->dest_idx < gimple_phi_num_args (phi));

  /* Copy propagation needs to know what object occur in abnormal
     PHI nodes.  This is a convenient place to record such information.  */
  if (e->flags & EDGE_ABNORMAL)
    {
      SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def) = 1;
      SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)) = 1;
    }

  SET_PHI_ARG_DEF (phi, e->dest_idx, def);
}
Ejemplo n.º 2
0
tree
degenerate_phi_result (gimple phi)
{
  tree lhs = gimple_phi_result (phi);
  tree val = NULL;
  size_t i;

  /* Ignoring arguments which are the same as LHS, if all the remaining
     arguments are the same, then the PHI is a degenerate and has the
     value of that common argument.  */
  for (i = 0; i < gimple_phi_num_args (phi); i++)
    {
      tree arg = gimple_phi_arg_def (phi, i);

      if (arg == lhs)
	continue;
      else if (!arg)
	break;
      else if (!val)
	val = arg;
      else if (arg == val)
	continue;
      /* We bring in some of operand_equal_p not only to speed things
	 up, but also to avoid crashing when dereferencing the type of
	 a released SSA name.  */
      else if (TREE_CODE (val) != TREE_CODE (arg)
	       || TREE_CODE (val) == SSA_NAME
	       || !operand_equal_p (arg, val, 0))
	break;
    }
  return (i == gimple_phi_num_args (phi) ? val : NULL);
}
Ejemplo n.º 3
0
static void
prop_phis (basic_block b)
{
  gimple_stmt_iterator psi;
  gimple_seq phis = phi_nodes (b);

  for (psi = gsi_start (phis); !gsi_end_p (psi); )
    {
      gimple phi = gsi_stmt (psi);
      tree def = gimple_phi_result (phi), use = gimple_phi_arg_def (phi, 0);

      gcc_assert (gimple_phi_num_args (phi) == 1);

      if (!is_gimple_reg (def))
	{
	  imm_use_iterator iter;
	  use_operand_p use_p;
	  gimple stmt;

	  FOR_EACH_IMM_USE_STMT (stmt, iter, def)
	    FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
	      SET_USE (use_p, use);
	}
      else
	replace_uses_by (def, use);

      remove_phi_node (&psi, true);
    }
}
Ejemplo n.º 4
0
static void
remove_duplicate_close_phi (gphi *phi, gphi_iterator *gsi)
{
  gimple *use_stmt;
  use_operand_p use_p;
  imm_use_iterator imm_iter;
  tree res = gimple_phi_result (phi);
  tree def = gimple_phi_result (gsi->phi ());

  gcc_assert (same_close_phi_node (phi, gsi->phi ()));

  FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, def)
    {
      FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
	SET_USE (use_p, res);

      update_stmt (use_stmt);

      /* It is possible that we just created a duplicate close-phi
	 for an already-processed containing loop.  Check for this
	 case and clean it up.  */
      if (gimple_code (use_stmt) == GIMPLE_PHI
	  && gimple_phi_num_args (use_stmt) == 1)
	make_close_phi_nodes_unique (gimple_bb (use_stmt));
    }
Ejemplo n.º 5
0
static void
remove_phi_arg_num (gimple phi, int i)
{
  int num_elem = gimple_phi_num_args (phi);

  gcc_assert (i < num_elem);

  /* Delink the item which is being removed.  */
  delink_imm_use (gimple_phi_arg_imm_use_ptr (phi, i));

  /* If it is not the last element, move the last element
     to the element we want to delete, resetting all the links. */
  if (i != num_elem - 1)
    {
      use_operand_p old_p, new_p;
      old_p = gimple_phi_arg_imm_use_ptr (phi, num_elem - 1);
      new_p = gimple_phi_arg_imm_use_ptr (phi, i);
      /* Set use on new node, and link into last element's place.  */
      *(new_p->use) = *(old_p->use);
      relink_imm_use (new_p, old_p);
    }

  /* Shrink the vector and return.  Note that we do not have to clear
     PHI_ARG_DEF because the garbage collector will not look at those
     elements beyond the first PHI_NUM_ARGS elements of the array.  */
  phi->gimple_phi.nargs--;
}
Ejemplo n.º 6
0
static gimple
resize_phi_node (gimple phi, size_t len)
{
  size_t old_size, i;
  gimple new_phi;

  gcc_assert (len > gimple_phi_capacity (phi));

  /* The garbage collector will not look at the PHI node beyond the
     first PHI_NUM_ARGS elements.  Therefore, all we have to copy is a
     portion of the PHI node currently in use.  */
  old_size = sizeof (struct gimple_statement_phi)
	     + (gimple_phi_num_args (phi) - 1) * sizeof (struct phi_arg_d);

  new_phi = allocate_phi_node (len);

  memcpy (new_phi, phi, old_size);

  for (i = 0; i < gimple_phi_num_args (new_phi); i++)
    {
      use_operand_p imm, old_imm;
      imm = gimple_phi_arg_imm_use_ptr (new_phi, i);
      old_imm = gimple_phi_arg_imm_use_ptr (phi, i);
      imm->use = gimple_phi_arg_def_ptr (new_phi, i);
      relink_imm_use_stmt (imm, old_imm, new_phi);
    }

  new_phi->gimple_phi.capacity = len;

  for (i = gimple_phi_num_args (new_phi); i < len; i++)
    {
      use_operand_p imm;

      gimple_phi_arg_set_location (new_phi, i, UNKNOWN_LOCATION);
      imm = gimple_phi_arg_imm_use_ptr (new_phi, i);
      imm->use = gimple_phi_arg_def_ptr (new_phi, i);
      imm->prev = NULL;
      imm->next = NULL;
      imm->loc.stmt = new_phi;
    }

  return new_phi;
}
Ejemplo n.º 7
0
static void
output_phi (struct output_block *ob, gimple phi)
{
  unsigned i, len = gimple_phi_num_args (phi);

  streamer_write_record_start (ob, lto_gimple_code_to_tag (GIMPLE_PHI));
  streamer_write_uhwi (ob, SSA_NAME_VERSION (PHI_RESULT (phi)));

  for (i = 0; i < len; i++)
    {
      stream_write_tree (ob, gimple_phi_arg_def (phi, i), true);
      streamer_write_uhwi (ob, gimple_phi_arg_edge (phi, i)->src->index);
      lto_output_location (ob, gimple_phi_arg_location (phi, i));
    }
}
Ejemplo n.º 8
0
static basic_block
find_bb_for_arg (gphi *phi, tree def)
{
  size_t i;
  bool foundone = false;
  basic_block result = NULL;
  for (i = 0; i < gimple_phi_num_args (phi); i++)
    if (PHI_ARG_DEF (phi, i) == def)
      {
	if (foundone)
	  return NULL;
	foundone = true;
	result = gimple_phi_arg_edge (phi, i)->src;
      }
  return result;
}
static bool
check_final_bb (void)
{
  gimple_stmt_iterator gsi;

  info.phi_count = 0;
  for (gsi = gsi_start_phis (info.final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      gimple phi = gsi_stmt (gsi);
      unsigned int i;

      info.phi_count++;

      for (i = 0; i < gimple_phi_num_args (phi); i++)
	{
	  basic_block bb = gimple_phi_arg_edge (phi, i)->src;

	  if (bb == info.switch_bb
	      || (single_pred_p (bb) && single_pred (bb) == info.switch_bb))
	    {
	      tree reloc, val;

	      val = gimple_phi_arg_def (phi, i);
	      if (!is_gimple_ip_invariant (val))
		{
		  info.reason = "   Non-invariant value from a case\n";
		  return false; /* Non-invariant argument.  */
		}
	      reloc = initializer_constant_valid_p (val, TREE_TYPE (val));
	      if ((flag_pic && reloc != null_pointer_node)
		  || (!flag_pic && reloc == NULL_TREE))
		{
		  if (reloc)
		    info.reason
		      = "   Value from a case would need runtime relocations\n";
		  else
		    info.reason
		      = "   Value from a case is not a valid initializer\n";
		  return false;
		}
	    }
	}
    }

  return true;
}
Ejemplo n.º 10
0
static bool
afdo_set_bb_count (basic_block bb, const stmt_set &promoted)
{
  gimple_stmt_iterator gsi;
  edge e;
  edge_iterator ei;
  gcov_type max_count = 0;
  bool has_annotated = false;

  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      count_info info;
      gimple *stmt = gsi_stmt (gsi);
      if (gimple_clobber_p (stmt) || is_gimple_debug (stmt))
        continue;
      if (afdo_source_profile->get_count_info (stmt, &info))
        {
          if (info.count > max_count)
            max_count = info.count;
          has_annotated = true;
          if (info.targets.size () > 0
              && promoted.find (stmt) == promoted.end ())
            afdo_vpt (&gsi, info.targets, false);
        }
    }

  if (!has_annotated)
    return false;

  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
    afdo_source_profile->mark_annotated (gimple_location (gsi_stmt (gsi)));
  for (gphi_iterator gpi = gsi_start_phis (bb);
       !gsi_end_p (gpi);
       gsi_next (&gpi))
    {
      gphi *phi = gpi.phi ();
      size_t i;
      for (i = 0; i < gimple_phi_num_args (phi); i++)
        afdo_source_profile->mark_annotated (gimple_phi_arg_location (phi, i));
    }
  FOR_EACH_EDGE (e, ei, bb->succs)
  afdo_source_profile->mark_annotated (e->goto_locus);

  bb->count = profile_count::from_gcov_type (max_count).afdo ();
  return true;
}
Ejemplo n.º 11
0
void
release_phi_node (gimple phi)
{
  size_t bucket;
  size_t len = gimple_phi_capacity (phi);
  size_t x;

  for (x = 0; x < gimple_phi_num_args (phi); x++)
    {
      use_operand_p  imm;
      imm = gimple_phi_arg_imm_use_ptr (phi, x);
      delink_imm_use (imm);
    }

  bucket = len > NUM_BUCKETS - 1 ? NUM_BUCKETS - 1 : len;
  bucket -= 2;
  VEC_safe_push (gimple, gc, free_phinodes[bucket], phi);
  free_phinode_count++;
}
Ejemplo n.º 12
0
DEBUG_FUNCTION void
verify_ssaname_freelists (struct function *fun)
{
  if (!gimple_in_ssa_p (fun))
    return;

  bitmap names_in_il = BITMAP_ALLOC (NULL);

  /* Walk the entire IL noting every SSA_NAME we see.  */
  basic_block bb;
  FOR_EACH_BB_FN (bb, fun)
    {
      tree t;
      /* First note the result and arguments of PHI nodes.  */
      for (gphi_iterator gsi = gsi_start_phis (bb);
	   !gsi_end_p (gsi);
	   gsi_next (&gsi))
	{
	  gphi *phi = gsi.phi ();
	  t = gimple_phi_result (phi);
	  bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));

	  for (unsigned int i = 0; i < gimple_phi_num_args (phi); i++)
	    {
	      t = gimple_phi_arg_def (phi, i);
	      if (TREE_CODE (t) == SSA_NAME)
		bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));
	    }
	}

      /* Then note the operands of each statement.  */
      for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
	   !gsi_end_p (gsi);
	   gsi_next (&gsi))
	{
	  ssa_op_iter iter;
	  gimple *stmt = gsi_stmt (gsi);
	  FOR_EACH_SSA_TREE_OPERAND (t, stmt, iter, SSA_OP_ALL_OPERANDS)
	    bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));
	}
    }
Ejemplo n.º 13
0
static bool
factor_out_conditional_conversion (edge e0, edge e1, gphi *phi,
				   tree arg0, tree arg1)
{
  gimple arg0_def_stmt = NULL, arg1_def_stmt = NULL, new_stmt;
  tree new_arg0 = NULL_TREE, new_arg1 = NULL_TREE;
  tree temp, result;
  gphi *newphi;
  gimple_stmt_iterator gsi, gsi_for_def;
  source_location locus = gimple_location (phi);
  enum tree_code convert_code;

  /* Handle only PHI statements with two arguments.  TODO: If all
     other arguments to PHI are INTEGER_CST or if their defining
     statement have the same unary operation, we can handle more
     than two arguments too.  */
  if (gimple_phi_num_args (phi) != 2)
    return false;

  /* First canonicalize to simplify tests.  */
  if (TREE_CODE (arg0) != SSA_NAME)
    {
      std::swap (arg0, arg1);
      std::swap (e0, e1);
    }

  if (TREE_CODE (arg0) != SSA_NAME
      || (TREE_CODE (arg1) != SSA_NAME
	  && TREE_CODE (arg1) != INTEGER_CST))
    return false;

  /* Check if arg0 is an SSA_NAME and the stmt which defines arg0 is
     a conversion.  */
  arg0_def_stmt = SSA_NAME_DEF_STMT (arg0);
  if (!is_gimple_assign (arg0_def_stmt)
      || !gimple_assign_cast_p (arg0_def_stmt))
    return false;

  /* Use the RHS as new_arg0.  */
  convert_code = gimple_assign_rhs_code (arg0_def_stmt);
  new_arg0 = gimple_assign_rhs1 (arg0_def_stmt);
  if (convert_code == VIEW_CONVERT_EXPR)
    new_arg0 = TREE_OPERAND (new_arg0, 0);

  if (TREE_CODE (arg1) == SSA_NAME)
    {
      /* Check if arg1 is an SSA_NAME and the stmt which defines arg1
	 is a conversion.  */
      arg1_def_stmt = SSA_NAME_DEF_STMT (arg1);
      if (!is_gimple_assign (arg1_def_stmt)
	  || gimple_assign_rhs_code (arg1_def_stmt) != convert_code)
	return false;

      /* Use the RHS as new_arg1.  */
      new_arg1 = gimple_assign_rhs1 (arg1_def_stmt);
      if (convert_code == VIEW_CONVERT_EXPR)
	new_arg1 = TREE_OPERAND (new_arg1, 0);
    }
  else
    {
      /* If arg1 is an INTEGER_CST, fold it to new type.  */
      if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0))
	  && int_fits_type_p (arg1, TREE_TYPE (new_arg0)))
	{
	  if (gimple_assign_cast_p (arg0_def_stmt))
	    new_arg1 = fold_convert (TREE_TYPE (new_arg0), arg1);
	  else
	    return false;
	}
      else
	return false;
    }

  /*  If arg0/arg1 have > 1 use, then this transformation actually increases
      the number of expressions evaluated at runtime.  */
  if (!has_single_use (arg0)
      || (arg1_def_stmt && !has_single_use (arg1)))
    return false;

  /* If types of new_arg0 and new_arg1 are different bailout.  */
  if (!types_compatible_p (TREE_TYPE (new_arg0), TREE_TYPE (new_arg1)))
    return false;

  /* Create a new PHI stmt.  */
  result = PHI_RESULT (phi);
  temp = make_ssa_name (TREE_TYPE (new_arg0), NULL);
  newphi = create_phi_node (temp, gimple_bb (phi));

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "PHI ");
      print_generic_expr (dump_file, gimple_phi_result (phi), 0);
      fprintf (dump_file,
	       " changed to factor conversion out from COND_EXPR.\n");
      fprintf (dump_file, "New stmt with CAST that defines ");
      print_generic_expr (dump_file, result, 0);
      fprintf (dump_file, ".\n");
    }

  /* Remove the old cast(s) that has single use.  */
  gsi_for_def = gsi_for_stmt (arg0_def_stmt);
  gsi_remove (&gsi_for_def, true);
  if (arg1_def_stmt)
    {
      gsi_for_def = gsi_for_s
Ejemplo n.º 14
0
static unsigned int
rename_ssa_copies (void)
{
  var_map map;
  basic_block bb;
  gimple_stmt_iterator gsi;
  tree var, part_var;
  gimple stmt, phi;
  unsigned x;
  FILE *debug;
  bool updated = false;

  memset (&stats, 0, sizeof (stats));

  if (dump_file && (dump_flags & TDF_DETAILS))
    debug = dump_file;
  else
    debug = NULL;

  map = init_var_map (num_ssa_names);

  FOR_EACH_BB (bb)
    {
      /* Scan for real copies.  */
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  stmt = gsi_stmt (gsi);
	  if (gimple_assign_ssa_name_copy_p (stmt))
	    {
	      tree lhs = gimple_assign_lhs (stmt);
	      tree rhs = gimple_assign_rhs1 (stmt);

	      updated |= copy_rename_partition_coalesce (map, lhs, rhs, debug);
	    }
	}
    }

  FOR_EACH_BB (bb)
    {
      /* Treat PHI nodes as copies between the result and each argument.  */
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          size_t i;
	  tree res;

	  phi = gsi_stmt (gsi);
	  res = gimple_phi_result (phi);

	  /* Do not process virtual SSA_NAMES.  */
	  if (virtual_operand_p (res))
	    continue;

	  /* Make sure to only use the same partition for an argument
	     as the result but never the other way around.  */
	  if (SSA_NAME_VAR (res)
	      && !DECL_IGNORED_P (SSA_NAME_VAR (res)))
	    for (i = 0; i < gimple_phi_num_args (phi); i++)
	      {
		tree arg = PHI_ARG_DEF (phi, i);
		if (TREE_CODE (arg) == SSA_NAME)
		  updated |= copy_rename_partition_coalesce (map, res, arg,
							     debug);
	      }
	  /* Else if all arguments are in the same partition try to merge
	     it with the result.  */
	  else
	    {
	      int all_p_same = -1;
	      int p = -1;
	      for (i = 0; i < gimple_phi_num_args (phi); i++)
		{
		  tree arg = PHI_ARG_DEF (phi, i);
		  if (TREE_CODE (arg) != SSA_NAME)
		    {
		      all_p_same = 0;
		      break;
		    }
		  else if (all_p_same == -1)
		    {
		      p = partition_find (map->var_partition,
					  SSA_NAME_VERSION (arg));
		      all_p_same = 1;
		    }
		  else if (all_p_same == 1
			   && p != partition_find (map->var_partition,
						   SSA_NAME_VERSION (arg)))
		    {
		      all_p_same = 0;
		      break;
		    }
		}
	      if (all_p_same == 1)
		updated |= copy_rename_partition_coalesce (map, res,
							   PHI_ARG_DEF (phi, 0),
							   debug);
	    }
        }
    }

  if (debug)
    dump_var_map (debug, map);

  /* Now one more pass to make all elements of a partition share the same
     root variable.  */

  for (x = 1; x < num_ssa_names; x++)
    {
      part_var = partition_to_var (map, x);
      if (!part_var)
        continue;
      var = ssa_name (x);
      if (SSA_NAME_VAR (var) == SSA_NAME_VAR (part_var))
	continue;
      if (debug)
        {
	  fprintf (debug, "Coalesced ");
	  print_generic_expr (debug, var, TDF_SLIM);
	  fprintf (debug, " to ");
	  print_generic_expr (debug, part_var, TDF_SLIM);
	  fprintf (debug, "\n");
	}
      stats.coalesced++;
      replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var));
    }

  statistics_counter_event (cfun, "copies coalesced",
			    stats.coalesced);
  delete_var_map (map);
  return updated ? TODO_remove_unused_locals : 0;
}
Ejemplo n.º 15
0
static enum ssa_prop_result
copy_prop_visit_phi_node (gimple phi)
{
  enum ssa_prop_result retval;
  unsigned i;
  prop_value_t phi_val = { NULL_TREE };

  tree lhs = gimple_phi_result (phi);

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "\nVisiting PHI node: ");
      print_gimple_stmt (dump_file, phi, 0, dump_flags);
    }

  for (i = 0; i < gimple_phi_num_args (phi); i++)
    {
      prop_value_t *arg_val;
      tree arg_value;
      tree arg = gimple_phi_arg_def (phi, i);
      edge e = gimple_phi_arg_edge (phi, i);

      /* We don't care about values flowing through non-executable
	 edges.  */
      if (!(e->flags & EDGE_EXECUTABLE))
	continue;

      /* Names that flow through abnormal edges cannot be used to
	 derive copies.  */
      if (TREE_CODE (arg) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (arg))
	{
	  phi_val.value = lhs;
	  break;
	}

      if (dump_file && (dump_flags & TDF_DETAILS))
	{
	  fprintf (dump_file, "\tArgument #%d: ", i);
	  dump_copy_of (dump_file, arg);
	  fprintf (dump_file, "\n");
	}

      if (TREE_CODE (arg) == SSA_NAME)
	{
	  arg_val = get_copy_of_val (arg);

	  /* If we didn't visit the definition of arg yet treat it as
	     UNDEFINED.  This also handles PHI arguments that are the
	     same as lhs.  We'll come here again.  */
	  if (!arg_val->value)
	    continue;

	  arg_value = arg_val->value;
	}
      else
	arg_value = valueize_val (arg);

      /* Avoid copy propagation from an inner into an outer loop.
	 Otherwise, this may move loop variant variables outside of
	 their loops and prevent coalescing opportunities.  If the
	 value was loop invariant, it will be hoisted by LICM and
	 exposed for copy propagation.
	 ???  The value will be always loop invariant.
	 In loop-closed SSA form do not copy-propagate through
	 PHI nodes in blocks with a loop exit edge predecessor.  */
      if (current_loops
	  && TREE_CODE (arg_value) == SSA_NAME
	  && (loop_depth_of_name (arg_value) > loop_depth_of_name (lhs)
	      || (loops_state_satisfies_p (LOOP_CLOSED_SSA)
		  && loop_exit_edge_p (e->src->loop_father, e))))
	{
	  phi_val.value = lhs;
	  break;
	}

      /* If the LHS didn't have a value yet, make it a copy of the
	 first argument we find.   */
      if (phi_val.value == NULL_TREE)
	{
	  phi_val.value = arg_value;
	  continue;
	}

      /* If PHI_VAL and ARG don't have a common copy-of chain, then
	 this PHI node cannot be a copy operation.  */
      if (phi_val.value != arg_value
	  && !operand_equal_p (phi_val.value, arg_value, 0))
	{
	  phi_val.value = lhs;
	  break;
	}
    }

  if (phi_val.value
      && may_propagate_copy (lhs, phi_val.value)
      && set_copy_of_val (lhs, phi_val.value))
    retval = (phi_val.value != lhs) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
  else
    retval = SSA_PROP_NOT_INTERESTING;

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "PHI node ");
      dump_copy_of (dump_file, lhs);
      fprintf (dump_file, "\nTelling the propagator to ");
      if (retval == SSA_PROP_INTERESTING)
	fprintf (dump_file, "add SSA edges out of this PHI and continue.");
      else if (retval == SSA_PROP_VARYING)
	fprintf (dump_file, "add SSA edges out of this PHI and never visit again.");
      else
	fprintf (dump_file, "do nothing with SSA edges and keep iterating.");
      fprintf (dump_file, "\n\n");
    }

  return retval;
}
Ejemplo n.º 16
0
static void
init_copy_prop (void)
{
  basic_block bb;

  copy_of = XCNEWVEC (prop_value_t, num_ssa_names);

  cached_last_copy_of = XCNEWVEC (tree, num_ssa_names);

  FOR_EACH_BB (bb)
    {
      gimple_stmt_iterator si;
      int depth = bb->loop_depth;

      for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
	{
	  gimple stmt = gsi_stmt (si);
	  ssa_op_iter iter;
          tree def;

	  /* The only statements that we care about are those that may
	     generate useful copies.  We also need to mark conditional
	     jumps so that their outgoing edges are added to the work
	     lists of the propagator.

	     Avoid copy propagation from an inner into an outer loop.
	     Otherwise, this may move loop variant variables outside of
	     their loops and prevent coalescing opportunities.  If the
	     value was loop invariant, it will be hoisted by LICM and
	     exposed for copy propagation.  */
	  if (stmt_ends_bb_p (stmt))
            prop_set_simulate_again (stmt, true);
	  else if (stmt_may_generate_copy (stmt)
                   /* Since we are iterating over the statements in
                      BB, not the phi nodes, STMT will always be an
                      assignment.  */
                   && loop_depth_of_name (gimple_assign_rhs1 (stmt)) <= depth)
            prop_set_simulate_again (stmt, true);
	  else
            prop_set_simulate_again (stmt, false);

	  /* Mark all the outputs of this statement as not being
	     the copy of anything.  */
	  FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
            if (!prop_simulate_again_p (stmt))
	      set_copy_of_val (def, def);
	    else
	      cached_last_copy_of[SSA_NAME_VERSION (def)] = def;
	}

      for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
	{
          gimple phi = gsi_stmt (si);
          tree def;

	  def = gimple_phi_result (phi);
	  if (!is_gimple_reg (def)
	      /* In loop-closed SSA form do not copy-propagate through
	         PHI nodes.  Technically this is only needed for loop
		 exit PHIs, but this is difficult to query.  */
	      || (current_loops
		  && gimple_phi_num_args (phi) == 1
		  && loops_state_satisfies_p (LOOP_CLOSED_SSA)))
            prop_set_simulate_again (phi, false);
	  else
            prop_set_simulate_again (phi, true);

	  if (!prop_simulate_again_p (phi))
	    set_copy_of_val (def, def);
	  else
	    cached_last_copy_of[SSA_NAME_VERSION (def)] = def;
	}
    }
}
Ejemplo n.º 17
0
static enum ssa_prop_result
copy_prop_visit_phi_node (gimple phi)
{
  enum ssa_prop_result retval;
  unsigned i;
  prop_value_t phi_val = { 0, NULL_TREE };

  tree lhs = gimple_phi_result (phi);

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "\nVisiting PHI node: ");
      print_gimple_stmt (dump_file, phi, 0, dump_flags);
      fprintf (dump_file, "\n\n");
    }

  for (i = 0; i < gimple_phi_num_args (phi); i++)
    {
      prop_value_t *arg_val;
      tree arg = gimple_phi_arg_def (phi, i);
      edge e = gimple_phi_arg_edge (phi, i);

      /* We don't care about values flowing through non-executable
	 edges.  */
      if (!(e->flags & EDGE_EXECUTABLE))
	continue;

      /* Constants in the argument list never generate a useful copy.
	 Similarly, names that flow through abnormal edges cannot be
	 used to derive copies.  */
      if (TREE_CODE (arg) != SSA_NAME || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (arg))
	{
	  phi_val.value = lhs;
	  break;
	}

      /* Avoid copy propagation from an inner into an outer loop.
	 Otherwise, this may move loop variant variables outside of
	 their loops and prevent coalescing opportunities.  If the
	 value was loop invariant, it will be hoisted by LICM and
	 exposed for copy propagation.  Not a problem for virtual
	 operands though.  */
      if (is_gimple_reg (lhs)
	  && loop_depth_of_name (arg) > loop_depth_of_name (lhs))
	{
	  phi_val.value = lhs;
	  break;
	}

      /* If the LHS appears in the argument list, ignore it.  It is
	 irrelevant as a copy.  */
      if (arg == lhs || get_last_copy_of (arg) == lhs)
	continue;

      if (dump_file && (dump_flags & TDF_DETAILS))
	{
	  fprintf (dump_file, "\tArgument #%d: ", i);
	  dump_copy_of (dump_file, arg);
	  fprintf (dump_file, "\n");
	}

      arg_val = get_copy_of_val (arg);

      /* If the LHS didn't have a value yet, make it a copy of the
	 first argument we find.  Notice that while we make the LHS be
	 a copy of the argument itself, we take the memory reference
	 from the argument's value so that we can compare it to the
	 memory reference of all the other arguments.  */
      if (phi_val.value == NULL_TREE)
	{
	  phi_val.value = arg_val->value ? arg_val->value : arg;
	  continue;
	}

      /* If PHI_VAL and ARG don't have a common copy-of chain, then
	 this PHI node cannot be a copy operation.  Also, if we are
	 copy propagating stores and these two arguments came from
	 different memory references, they cannot be considered
	 copies.  */
      if (get_last_copy_of (phi_val.value) != get_last_copy_of (arg))
	{
	  phi_val.value = lhs;
	  break;
	}
    }

  if (phi_val.value &&  may_propagate_copy (lhs, phi_val.value)
      && set_copy_of_val (lhs, phi_val.value))
    retval = (phi_val.value != lhs) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
  else
    retval = SSA_PROP_NOT_INTERESTING;

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "\nPHI node ");
      dump_copy_of (dump_file, lhs);
      fprintf (dump_file, "\nTelling the propagator to ");
      if (retval == SSA_PROP_INTERESTING)
	fprintf (dump_file, "add SSA edges out of this PHI and continue.");
      else if (retval == SSA_PROP_VARYING)
	fprintf (dump_file, "add SSA edges out of this PHI and never visit again.");
      else
	fprintf (dump_file, "do nothing with SSA edges and keep iterating.");
      fprintf (dump_file, "\n\n");
    }

  return retval;
}
/* Look for PHI nodes which feed statements in the same block where
   the value of the PHI node implies the statement is erroneous.

   For example, a NULL PHI arg value which then feeds a pointer
   dereference.

   When found isolate and optimize the path associated with the PHI
   argument feeding the erroneous statement.  */
static void
find_implicit_erroneous_behaviour (void)
{
  basic_block bb;

  FOR_EACH_BB_FN (bb, cfun)
    {
      gimple_stmt_iterator si;

      /* Out of an abundance of caution, do not isolate paths to a
	 block where the block has any abnormal outgoing edges.

	 We might be able to relax this in the future.  We have to detect
	 when we have to split the block with the NULL dereference and
	 the trap we insert.  We have to preserve abnormal edges out
	 of the isolated block which in turn means updating PHIs at
	 the targets of those abnormal outgoing edges.  */
      if (has_abnormal_or_eh_outgoing_edge_p (bb))
	continue;

      /* First look for a PHI which sets a pointer to NULL and which
 	 is then dereferenced within BB.  This is somewhat overly
	 conservative, but probably catches most of the interesting
	 cases.   */
      for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
	{
	  gimple phi = gsi_stmt (si);
	  tree lhs = gimple_phi_result (phi);

	  /* If the result is not a pointer, then there is no need to
 	     examine the arguments.  */
	  if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
	    continue;

	  /* PHI produces a pointer result.  See if any of the PHI's
	     arguments are NULL.

	     When we remove an edge, we want to reprocess the current
	     index, hence the ugly way we update I for each iteration.  */
	  basic_block duplicate = NULL;
	  for (unsigned i = 0, next_i = 0;
	       i < gimple_phi_num_args (phi);
	       i = next_i)
	    {
	      tree op = gimple_phi_arg_def (phi, i);

	      next_i = i + 1;

	      if (!integer_zerop (op))
		continue;

	      edge e = gimple_phi_arg_edge (phi, i);
	      imm_use_iterator iter;
	      gimple use_stmt;

	      /* We've got a NULL PHI argument.  Now see if the
 	         PHI's result is dereferenced within BB.  */
	      FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
	        {
	          /* We only care about uses in BB.  Catching cases in
		     in other blocks would require more complex path
		     isolation code.   */
		  if (gimple_bb (use_stmt) != bb)
		    continue;

		  if (infer_nonnull_range (use_stmt, lhs,
					   flag_isolate_erroneous_paths_dereference,
					   flag_isolate_erroneous_paths_attribute))

		    {
		      duplicate = isolate_path (bb, duplicate,
						e, use_stmt, lhs);

		      /* When we remove an incoming edge, we need to
			 reprocess the Ith element.  */
		      next_i = i;
		      cfg_altered = true;
		    }
		}
	    }
	}
    }
Ejemplo n.º 19
0
static unsigned int
rename_ssa_copies (void)
{
  var_map map;
  basic_block bb;
  gimple_stmt_iterator gsi;
  tree var, part_var;
  gimple stmt, phi;
  unsigned x;
  FILE *debug;
  bool updated = false;

  if (dump_file && (dump_flags & TDF_DETAILS))
    debug = dump_file;
  else
    debug = NULL;

  map = init_var_map (num_ssa_names);

  FOR_EACH_BB (bb)
    {
      /* Scan for real copies.  */
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  stmt = gsi_stmt (gsi);
	  if (gimple_assign_ssa_name_copy_p (stmt))
	    {
	      tree lhs = gimple_assign_lhs (stmt);
	      tree rhs = gimple_assign_rhs1 (stmt);

	      updated |= copy_rename_partition_coalesce (map, lhs, rhs, debug);
	    }
	}
    }

  FOR_EACH_BB (bb)
    {
      /* Treat PHI nodes as copies between the result and each argument.  */
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          size_t i;
	  tree res;

	  phi = gsi_stmt (gsi);
	  res = gimple_phi_result (phi);

	  /* Do not process virtual SSA_NAMES.  */
	  if (!is_gimple_reg (SSA_NAME_VAR (res)))
	    continue;

          for (i = 0; i < gimple_phi_num_args (phi); i++)
            {
              tree arg = gimple_phi_arg (phi, i)->def;
              if (TREE_CODE (arg) == SSA_NAME)
		updated |= copy_rename_partition_coalesce (map, res, arg, debug);
            }
        }
    }

  if (debug)
    dump_var_map (debug, map);

  /* Now one more pass to make all elements of a partition share the same
     root variable.  */

  for (x = 1; x < num_ssa_names; x++)
    {
      part_var = partition_to_var (map, x);
      if (!part_var)
        continue;
      var = ssa_name (x);
      if (debug)
        {
	  if (SSA_NAME_VAR (var) != SSA_NAME_VAR (part_var))
	    {
	      fprintf (debug, "Coalesced ");
	      print_generic_expr (debug, var, TDF_SLIM);
	      fprintf (debug, " to ");
	      print_generic_expr (debug, part_var, TDF_SLIM);
	      fprintf (debug, "\n");
	    }
	}
      replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var));
    }

  delete_var_map (map);
  return updated ? TODO_remove_unused_locals : 0;
}
Ejemplo n.º 20
0
expr_hash_elt::expr_hash_elt (gimple *stmt, tree orig_lhs)
{
  enum gimple_code code = gimple_code (stmt);
  struct hashable_expr *expr = this->expr ();

  if (code == GIMPLE_ASSIGN)
    {
      enum tree_code subcode = gimple_assign_rhs_code (stmt);

      switch (get_gimple_rhs_class (subcode))
        {
        case GIMPLE_SINGLE_RHS:
	  expr->kind = EXPR_SINGLE;
	  expr->type = TREE_TYPE (gimple_assign_rhs1 (stmt));
	  expr->ops.single.rhs = gimple_assign_rhs1 (stmt);
	  break;
        case GIMPLE_UNARY_RHS:
	  expr->kind = EXPR_UNARY;
	  expr->type = TREE_TYPE (gimple_assign_lhs (stmt));
	  if (CONVERT_EXPR_CODE_P (subcode))
	    subcode = NOP_EXPR;
	  expr->ops.unary.op = subcode;
	  expr->ops.unary.opnd = gimple_assign_rhs1 (stmt);
	  break;
        case GIMPLE_BINARY_RHS:
	  expr->kind = EXPR_BINARY;
	  expr->type = TREE_TYPE (gimple_assign_lhs (stmt));
	  expr->ops.binary.op = subcode;
	  expr->ops.binary.opnd0 = gimple_assign_rhs1 (stmt);
	  expr->ops.binary.opnd1 = gimple_assign_rhs2 (stmt);
	  break;
        case GIMPLE_TERNARY_RHS:
	  expr->kind = EXPR_TERNARY;
	  expr->type = TREE_TYPE (gimple_assign_lhs (stmt));
	  expr->ops.ternary.op = subcode;
	  expr->ops.ternary.opnd0 = gimple_assign_rhs1 (stmt);
	  expr->ops.ternary.opnd1 = gimple_assign_rhs2 (stmt);
	  expr->ops.ternary.opnd2 = gimple_assign_rhs3 (stmt);
	  break;
        default:
          gcc_unreachable ();
        }
    }
  else if (code == GIMPLE_COND)
    {
      expr->type = boolean_type_node;
      expr->kind = EXPR_BINARY;
      expr->ops.binary.op = gimple_cond_code (stmt);
      expr->ops.binary.opnd0 = gimple_cond_lhs (stmt);
      expr->ops.binary.opnd1 = gimple_cond_rhs (stmt);
    }
  else if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
    {
      size_t nargs = gimple_call_num_args (call_stmt);
      size_t i;

      gcc_assert (gimple_call_lhs (call_stmt));

      expr->type = TREE_TYPE (gimple_call_lhs (call_stmt));
      expr->kind = EXPR_CALL;
      expr->ops.call.fn_from = call_stmt;

      if (gimple_call_flags (call_stmt) & (ECF_CONST | ECF_PURE))
        expr->ops.call.pure = true;
      else
        expr->ops.call.pure = false;

      expr->ops.call.nargs = nargs;
      expr->ops.call.args = XCNEWVEC (tree, nargs);
      for (i = 0; i < nargs; i++)
        expr->ops.call.args[i] = gimple_call_arg (call_stmt, i);
    }
  else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
    {
      expr->type = TREE_TYPE (gimple_switch_index (swtch_stmt));
      expr->kind = EXPR_SINGLE;
      expr->ops.single.rhs = gimple_switch_index (swtch_stmt);
    }
  else if (code == GIMPLE_GOTO)
    {
      expr->type = TREE_TYPE (gimple_goto_dest (stmt));
      expr->kind = EXPR_SINGLE;
      expr->ops.single.rhs = gimple_goto_dest (stmt);
    }
  else if (code == GIMPLE_PHI)
    {
      size_t nargs = gimple_phi_num_args (stmt);
      size_t i;

      expr->type = TREE_TYPE (gimple_phi_result (stmt));
      expr->kind = EXPR_PHI;
      expr->ops.phi.nargs = nargs;
      expr->ops.phi.args = XCNEWVEC (tree, nargs);
      for (i = 0; i < nargs; i++)
        expr->ops.phi.args[i] = gimple_phi_arg_def (stmt, i);
    }
  else
    gcc_unreachable ();

  m_lhs = orig_lhs;
  m_vop = gimple_vuse (stmt);
  m_hash = avail_expr_hash (this);
  m_stamp = this;
}