示例#1
0
static bool
stmt_may_generate_copy (gimple stmt)
{
  if (gimple_code (stmt) == GIMPLE_PHI)
    return !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt));

  if (gimple_code (stmt) != GIMPLE_ASSIGN)
    return false;

  /* If the statement has volatile operands, it won't generate a
     useful copy.  */
  if (gimple_has_volatile_ops (stmt))
    return false;

  /* Statements with loads and/or stores will never generate a useful copy.  */
  if (gimple_vuse (stmt))
    return false;

  /* Otherwise, the only statements that generate useful copies are
     assignments whose RHS is just an SSA name that doesn't flow
     through abnormal edges.  */
  return ((gimple_assign_rhs_code (stmt) == SSA_NAME
	   && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt)))
	  || is_gimple_min_invariant (gimple_assign_rhs1 (stmt)));
}
示例#2
0
文件: tree-ssa.c 项目: abumaryam/gcc
edge
ssa_redirect_edge (edge e, basic_block dest)
{
  gphi_iterator gsi;
  gphi *phi;

  redirect_edge_var_map_clear (e);

  /* Remove the appropriate PHI arguments in E's destination block.  */
  for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      tree def;
      source_location locus ;

      phi = gsi.phi ();
      def = gimple_phi_arg_def (phi, e->dest_idx);
      locus = gimple_phi_arg_location (phi, e->dest_idx);

      if (def == NULL_TREE)
	continue;

      redirect_edge_var_map_add (e, gimple_phi_result (phi), def, locus);
    }

  e = redirect_edge_succ_nodup (e, dest);

  return e;
}
static bool
stmt_has_scalar_dependences_outside_loop (gimple stmt)
{
  tree name;

  switch (gimple_code (stmt))
    {
    case GIMPLE_CALL:
    case GIMPLE_ASSIGN:
      name = gimple_get_lhs (stmt);
      break;

    case GIMPLE_PHI:
      name = gimple_phi_result (stmt);
      break;

    default:
      return false;
    }

  return (name
	  && TREE_CODE (name) == SSA_NAME
	  && ssa_name_has_uses_outside_loop_p (name,
					       loop_containing_stmt (stmt)));
}
示例#4
0
static unsigned
get_stmt_uid (gimple stmt)
{
  if (gimple_code (stmt) == GIMPLE_PHI)
    return SSA_NAME_VERSION (gimple_phi_result (stmt))
           + gimple_stmt_max_uid (cfun);

  return gimple_uid (stmt);
}
示例#5
0
void
output_bb (struct output_block *ob, basic_block bb, struct function *fn)
{
  gimple_stmt_iterator bsi = gsi_start_bb (bb);

  streamer_write_record_start (ob,
			       (!gsi_end_p (bsi)) || phi_nodes (bb)
			        ? LTO_bb1
				: LTO_bb0);

  streamer_write_uhwi (ob, bb->index);
  streamer_write_gcov_count (ob, bb->count);
  streamer_write_hwi (ob, bb->frequency);
  streamer_write_hwi (ob, bb->flags);

  if (!gsi_end_p (bsi) || phi_nodes (bb))
    {
      /* Output the statements.  The list of statements is terminated
	 with a zero.  */
      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
	{
	  int region;
	  gimple stmt = gsi_stmt (bsi);

	  output_gimple_stmt (ob, stmt);

	  /* Emit the EH region holding STMT.  */
	  region = lookup_stmt_eh_lp_fn (fn, stmt);
	  if (region != 0)
	    {
	      streamer_write_record_start (ob, LTO_eh_region);
	      streamer_write_hwi (ob, region);
	    }
	  else
	    streamer_write_record_start (ob, LTO_null);
	}

      streamer_write_record_start (ob, LTO_null);

      for (gphi_iterator psi = gsi_start_phis (bb);
	   !gsi_end_p (psi);
	   gsi_next (&psi))
	{
	  gphi *phi = psi.phi ();

	  /* Only emit PHIs for gimple registers.  PHI nodes for .MEM
	     will be filled in on reading when the SSA form is
	     updated.  */
	  if (!virtual_operand_p (gimple_phi_result (phi)))
	    output_phi (ob, phi);
	}

      streamer_write_record_start (ob, LTO_null);
    }
}
示例#6
0
static bool
generate_loops_for_partition (struct loop *loop, bitmap partition, bool copy_p)
{
  unsigned i, x;
  gimple_stmt_iterator bsi;
  basic_block *bbs;

  if (copy_p)
    {
      loop = copy_loop_before (loop);
      create_preheader (loop, CP_SIMPLE_PREHEADERS);
      create_bb_after_loop (loop);
    }

  if (loop == NULL)
    return false;

  /* Remove stmts not in the PARTITION bitmap.  The order in which we
     visit the phi nodes and the statements is exactly as in
     stmts_from_loop.  */
  bbs = get_loop_body_in_dom_order (loop);

  for (x = 0, i = 0; i < loop->num_nodes; i++)
    {
      basic_block bb = bbs[i];

      for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi);)
	if (!bitmap_bit_p (partition, x++))
	  {
	    gimple phi = gsi_stmt (bsi);
	    if (!is_gimple_reg (gimple_phi_result (phi)))
	      mark_virtual_phi_result_for_renaming (phi);
	    remove_phi_node (&bsi, true);
	  }
	else
	  gsi_next (&bsi);

      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi);)
	{
	  gimple stmt = gsi_stmt (bsi);
	  if (gimple_code (gsi_stmt (bsi)) != GIMPLE_LABEL
	      && !bitmap_bit_p (partition, x++))
	    {
	      unlink_stmt_vdef (stmt);
	      gsi_remove (&bsi, true);
	      release_defs (stmt);
	    }
	  else
	    gsi_next (&bsi);
	}
    }

  free (bbs);
  return true;
}
示例#7
0
void
remove_phi_node (gimple_stmt_iterator *gsi, bool release_lhs_p)
{
  gimple phi = gsi_stmt (*gsi);
  gsi_remove (gsi, false);

  /* If we are deleting the PHI node, then we should release the
     SSA_NAME node so that it can be reused.  */
  release_phi_node (phi);
  if (release_lhs_p)
    release_ssa_name (gimple_phi_result (phi));
}
示例#8
0
static void
init_copy_prop (void)
{
  basic_block bb;

  n_copy_of = num_ssa_names;
  copy_of = XCNEWVEC (prop_value_t, n_copy_of);

  FOR_EACH_BB_FN (bb, cfun)
    {
      for (gimple_stmt_iterator 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.  */
	  if (stmt_ends_bb_p (stmt))
            prop_set_simulate_again (stmt, true);
	  else if (stmt_may_generate_copy (stmt))
            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);
	}

      for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si);
	   gsi_next (&si))
	{
          gphi *phi = si.phi ();
          tree def;

	  def = gimple_phi_result (phi);
	  if (virtual_operand_p (def))
            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);
	}
    }
}
示例#9
0
void
backprop::process_block (basic_block bb)
{
  for (gimple_stmt_iterator gsi = gsi_last_bb (bb); !gsi_end_p (gsi);
       gsi_prev (&gsi))
    {
      tree lhs = gimple_get_lhs (gsi_stmt (gsi));
      if (lhs && TREE_CODE (lhs) == SSA_NAME)
	process_var (lhs);
    }
  for (gphi_iterator gpi = gsi_start_phis (bb); !gsi_end_p (gpi);
       gsi_next (&gpi))
    process_var (gimple_phi_result (gpi.phi ()));
}
示例#10
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));
	}
    }
示例#11
0
static void
eliminate_build (elim_graph g)
{
  tree Ti;
  int p0, pi;
  gimple_stmt_iterator gsi;

  clear_elim_graph (g);

  for (gsi = gsi_start_phis (g->e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      gimple phi = gsi_stmt (gsi);
      source_location locus;

      p0 = var_to_partition (g->map, gimple_phi_result (phi));
      /* Ignore results which are not in partitions.  */
      if (p0 == NO_PARTITION)
	continue;

      Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
      locus = gimple_phi_arg_location_from_edge (phi, g->e);

      /* If this argument is a constant, or a SSA_NAME which is being
	 left in SSA form, just queue a copy to be emitted on this
	 edge.  */
      if (!phi_ssa_name_p (Ti)
	  || (TREE_CODE (Ti) == SSA_NAME
	      && var_to_partition (g->map, Ti) == NO_PARTITION))
        {
	  /* Save constant copies until all other copies have been emitted
	     on this edge.  */
	  VEC_safe_push (int, heap, g->const_dests, p0);
	  VEC_safe_push (tree, heap, g->const_copies, Ti);
	  VEC_safe_push (source_location, heap, g->copy_locus, locus);
	}
      else
        {
示例#12
0
void
reserve_phi_args_for_new_edge (basic_block bb)
{
  size_t len = EDGE_COUNT (bb->preds);
  size_t cap = ideal_phi_node_len (len + 4);
  gimple_stmt_iterator gsi;

  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      gimple_statement_phi *stmt =
	as_a <gimple_statement_phi> (gsi_stmt (gsi));

      if (len > gimple_phi_capacity (stmt))
	{
	  gimple_statement_phi *new_phi = resize_phi_node (stmt, cap);

	  /* The result of the PHI is defined by this PHI node.  */
	  SSA_NAME_DEF_STMT (gimple_phi_result (new_phi)) = new_phi;
	  gsi_set_stmt (&gsi, new_phi);

	  release_phi_node (stmt);
	  stmt = new_phi;
	}

      /* We represent a "missing PHI argument" by placing NULL_TREE in
	 the corresponding slot.  If PHI arguments were added
	 immediately after an edge is created, this zeroing would not
	 be necessary, but unfortunately this is not the case.  For
	 example, the loop optimizer duplicates several basic blocks,
	 redirects edges, and then fixes up PHI arguments later in
	 batch.  */
      SET_PHI_ARG_DEF (stmt, len - 1, NULL_TREE);
      gimple_phi_arg_set_location (stmt, len - 1, UNKNOWN_LOCATION);

      stmt->nargs++;
    }
}
示例#13
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;
}
示例#14
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;
	}
    }
}
示例#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 = { 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;
}
示例#16
0
static bool
init_dont_simulate_again (void)
{
  basic_block bb;
  gimple_stmt_iterator gsi;
  gimple phi;
  bool saw_a_complex_op = false;

  FOR_EACH_BB (bb)
    {
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  phi = gsi_stmt (gsi);
	  prop_set_simulate_again (phi,
				   is_complex_reg (gimple_phi_result (phi)));
	}

      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	{
	  gimple stmt;
	  tree op0, op1;
	  bool sim_again_p;

	  stmt = gsi_stmt (gsi);
	  op0 = op1 = NULL_TREE;

	  /* Most control-altering statements must be initially 
	     simulated, else we won't cover the entire cfg.  */
	  sim_again_p = stmt_ends_bb_p (stmt);

	  switch (gimple_code (stmt))
	    {
	    case GIMPLE_CALL:
	      if (gimple_call_lhs (stmt))
	        sim_again_p = is_complex_reg (gimple_call_lhs (stmt));
	      break;

	    case GIMPLE_ASSIGN:
	      sim_again_p = is_complex_reg (gimple_assign_lhs (stmt));
	      if (gimple_assign_rhs_code (stmt) == REALPART_EXPR
		  || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR)
		op0 = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
	      else
		op0 = gimple_assign_rhs1 (stmt);
	      if (gimple_num_ops (stmt) > 2)
		op1 = gimple_assign_rhs2 (stmt);
	      break;

	    case GIMPLE_COND:
	      op0 = gimple_cond_lhs (stmt);
	      op1 = gimple_cond_rhs (stmt);
	      break;

	    default:
	      break;
	    }

	  if (op0 || op1)
	    switch (gimple_expr_code (stmt))
	      {
	      case EQ_EXPR:
	      case NE_EXPR:
	      case PLUS_EXPR:
	      case MINUS_EXPR:
	      case MULT_EXPR:
	      case TRUNC_DIV_EXPR:
	      case CEIL_DIV_EXPR:
	      case FLOOR_DIV_EXPR:
	      case ROUND_DIV_EXPR:
	      case RDIV_EXPR:
		if (TREE_CODE (TREE_TYPE (op0)) == COMPLEX_TYPE
		    || TREE_CODE (TREE_TYPE (op1)) == COMPLEX_TYPE)
		  saw_a_complex_op = true;
		break;

	      case NEGATE_EXPR:
	      case CONJ_EXPR:
		if (TREE_CODE (TREE_TYPE (op0)) == COMPLEX_TYPE)
		  saw_a_complex_op = true;
		break;

	      case REALPART_EXPR:
	      case IMAGPART_EXPR:
		/* The total store transformation performed during
		  gimplification creates such uninitialized loads
		  and we need to lower the statement to be able
		  to fix things up.  */
		if (TREE_CODE (op0) == SSA_NAME
		    && ssa_undefined_value_p (op0))
		  saw_a_complex_op = true;
		break;

	      default:
		break;
	      }

	  prop_set_simulate_again (stmt, sim_again_p);
	}
    }

  return saw_a_complex_op;
}
示例#17
0
tree
avail_exprs_stack::lookup_avail_expr (gimple *stmt, bool insert, bool tbaa_p)
{
  expr_hash_elt **slot;
  tree lhs;

  /* Get LHS of phi, assignment, or call; else NULL_TREE.  */
  if (gimple_code (stmt) == GIMPLE_PHI)
    lhs = gimple_phi_result (stmt);
  else
    lhs = gimple_get_lhs (stmt);

  class expr_hash_elt element (stmt, lhs);

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "LKUP ");
      element.print (dump_file);
    }

  /* Don't bother remembering constant assignments and copy operations.
     Constants and copy operations are handled by the constant/copy propagator
     in optimize_stmt.  */
  if (element.expr()->kind == EXPR_SINGLE
      && (TREE_CODE (element.expr()->ops.single.rhs) == SSA_NAME
          || is_gimple_min_invariant (element.expr()->ops.single.rhs)))
    return NULL_TREE;

  /* Finally try to find the expression in the main expression hash table.  */
  slot = m_avail_exprs->find_slot (&element, (insert ? INSERT : NO_INSERT));
  if (slot == NULL)
    {
      return NULL_TREE;
    }
  else if (*slot == NULL)
    {
      class expr_hash_elt *element2 = new expr_hash_elt (element);
      *slot = element2;

      record_expr (element2, NULL, '2');
      return NULL_TREE;
    }

  /* If we found a redundant memory operation do an alias walk to
     check if we can re-use it.  */
  if (gimple_vuse (stmt) != (*slot)->vop ())
    {
      tree vuse1 = (*slot)->vop ();
      tree vuse2 = gimple_vuse (stmt);
      /* If we have a load of a register and a candidate in the
	 hash with vuse1 then try to reach its stmt by walking
	 up the virtual use-def chain using walk_non_aliased_vuses.
	 But don't do this when removing expressions from the hash.  */
      ao_ref ref;
      if (!(vuse1 && vuse2
	    && gimple_assign_single_p (stmt)
	    && TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME
	    && (ao_ref_init (&ref, gimple_assign_rhs1 (stmt)),
		ref.base_alias_set = ref.ref_alias_set = tbaa_p ? -1 : 0, true)
	    && walk_non_aliased_vuses (&ref, vuse2,
				       vuse_eq, NULL, NULL, vuse1) != NULL))
	{
	  if (insert)
	    {
	      class expr_hash_elt *element2 = new expr_hash_elt (element);

	      /* Insert the expr into the hash by replacing the current
		 entry and recording the value to restore in the
		 avail_exprs_stack.  */
	      record_expr (element2, *slot, '2');
	      *slot = element2;
	    }
	  return NULL_TREE;
	}
    }

  /* Extract the LHS of the assignment so that it can be used as the current
     definition of another variable.  */
  lhs = (*slot)->lhs ();

  /* Valueize the result.  */
  if (TREE_CODE (lhs) == SSA_NAME)
    {
      tree tem = SSA_NAME_VALUE (lhs);
      if (tem)
	lhs = tem;
    }

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "FIND: ");
      print_generic_expr (dump_file, lhs, 0);
      fprintf (dump_file, "\n");
    }

  return lhs;
}
示例#18
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;
}
示例#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;
}
/* 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;
		    }
		}
	    }
	}
    }
static void
shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds,
					  unsigned int nconds)
{
  gimple_stmt_iterator bi_call_bsi;
  basic_block bi_call_bb, join_tgt_bb, guard_bb;
  edge join_tgt_in_edge_from_call, join_tgt_in_edge_fall_thru;
  edge bi_call_in_edge0, guard_bb_in_edge;
  unsigned tn_cond_stmts;
  unsigned ci;
  gimple *cond_expr = NULL;
  gimple *cond_expr_start;

  /* The cfg we want to create looks like this:

	   [guard n-1]         <- guard_bb (old block)
	     |    \
	     | [guard n-2]                   }
	     |    / \                        }
	     |   /  ...                      } new blocks
	     |  /  [guard 0]                 }
	     | /    /   |                    }
	    [ call ]    |     <- bi_call_bb  }
	     | \        |
	     |  \       |
	     |   [ join ]     <- join_tgt_bb (old iff call must end bb)
	     |
	 possible EH edges (only if [join] is old)

     When [join] is new, the immediate dominators for these blocks are:

     1. [guard n-1]: unchanged
     2. [call]: [guard n-1]
     3. [guard m]: [guard m+1] for 0 <= m <= n-2
     4. [join]: [guard n-1]

     We punt for the more complex case case of [join] being old and
     simply free the dominance info.  We also punt on postdominators,
     which aren't expected to be available at this point anyway.  */
  bi_call_bb = gimple_bb (bi_call);

  /* Now find the join target bb -- split bi_call_bb if needed.  */
  if (stmt_ends_bb_p (bi_call))
    {
      /* We checked that there was a fallthrough edge in
	 can_guard_call_p.  */
      join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs);
      gcc_assert (join_tgt_in_edge_from_call);
      /* We don't want to handle PHIs.  */
      if (EDGE_COUNT (join_tgt_in_edge_from_call->dest->preds) > 1)
	join_tgt_bb = split_edge (join_tgt_in_edge_from_call);
      else
	{
	  join_tgt_bb = join_tgt_in_edge_from_call->dest;
	  /* We may have degenerate PHIs in the destination.  Propagate
	     those out.  */
	  for (gphi_iterator i = gsi_start_phis (join_tgt_bb); !gsi_end_p (i);)
	    {
	      gphi *phi = i.phi ();
	      replace_uses_by (gimple_phi_result (phi),
			       gimple_phi_arg_def (phi, 0));
	      remove_phi_node (&i, true);
	    }
	}
    }
  else
    {
      join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call);
      join_tgt_bb = join_tgt_in_edge_from_call->dest;
    }

  bi_call_bsi = gsi_for_stmt (bi_call);

  /* Now it is time to insert the first conditional expression
     into bi_call_bb and split this bb so that bi_call is
     shrink-wrapped.  */
  tn_cond_stmts = conds.length ();
  cond_expr = NULL;
  cond_expr_start = conds[0];
  for (ci = 0; ci < tn_cond_stmts; ci++)
    {
      gimple *c = conds[ci];
      gcc_assert (c || ci != 0);
      if (!c)
        break;
      gsi_insert_before (&bi_call_bsi, c, GSI_SAME_STMT);
      cond_expr = c;
    }
  ci++;
  gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND);

  typedef std::pair<edge, edge> edge_pair;
  auto_vec<edge_pair, 8> edges;

  bi_call_in_edge0 = split_block (bi_call_bb, cond_expr);
  bi_call_in_edge0->flags &= ~EDGE_FALLTHRU;
  bi_call_in_edge0->flags |= EDGE_FALSE_VALUE;
  guard_bb = bi_call_bb;
  bi_call_bb = bi_call_in_edge0->dest;
  join_tgt_in_edge_fall_thru = make_edge (guard_bb, join_tgt_bb,
                                          EDGE_TRUE_VALUE);

  edges.reserve (nconds);
  edges.quick_push (edge_pair (bi_call_in_edge0, join_tgt_in_edge_fall_thru));

  /* Code generation for the rest of the conditions  */
  for (unsigned int i = 1; i < nconds; ++i)
    {
      unsigned ci0;
      edge bi_call_in_edge;
      gimple_stmt_iterator guard_bsi = gsi_for_stmt (cond_expr_start);
      ci0 = ci;
      cond_expr_start = conds[ci0];
      for (; ci < tn_cond_stmts; ci++)
        {
	  gimple *c = conds[ci];
          gcc_assert (c || ci != ci0);
          if (!c)
            break;
          gsi_insert_before (&guard_bsi, c, GSI_SAME_STMT);
          cond_expr = c;
        }
      ci++;
      gcc_assert (cond_expr && gimple_code (cond_expr) == GIMPLE_COND);
      guard_bb_in_edge = split_block (guard_bb, cond_expr);
      guard_bb_in_edge->flags &= ~EDGE_FALLTHRU;
      guard_bb_in_edge->flags |= EDGE_TRUE_VALUE;

      bi_call_in_edge = make_edge (guard_bb, bi_call_bb, EDGE_FALSE_VALUE);
      edges.quick_push (edge_pair (bi_call_in_edge, guard_bb_in_edge));
    }

  /* Now update the probability and profile information, processing the
     guards in order of execution.

     There are two approaches we could take here.  On the one hand we
     could assign a probability of X to the call block and distribute
     that probability among its incoming edges.  On the other hand we
     could assign a probability of X to each individual call edge.

     The choice only affects calls that have more than one condition.
     In those cases, the second approach would give the call block
     a greater probability than the first.  However, the difference
     is only small, and our chosen X is a pure guess anyway.

     Here we take the second approach because it's slightly simpler
     and because it's easy to see that it doesn't lose profile counts.  */
  bi_call_bb->count = profile_count::zero ();
  while (!edges.is_empty ())
    {
      edge_pair e = edges.pop ();
      edge call_edge = e.first;
      edge nocall_edge = e.second;
      basic_block src_bb = call_edge->src;
      gcc_assert (src_bb == nocall_edge->src);

      call_edge->probability = profile_probability::very_unlikely ();
      nocall_edge->probability = profile_probability::always ()
				 - call_edge->probability;

      bi_call_bb->count += call_edge->count ();

      if (nocall_edge->dest != join_tgt_bb)
	nocall_edge->dest->count = src_bb->count - bi_call_bb->count;
    }

  if (dom_info_available_p (CDI_DOMINATORS))
    {
      /* The split_blocks leave [guard 0] as the immediate dominator
	 of [call] and [call] as the immediate dominator of [join].
	 Fix them up.  */
      set_immediate_dominator (CDI_DOMINATORS, bi_call_bb, guard_bb);
      set_immediate_dominator (CDI_DOMINATORS, join_tgt_bb, guard_bb);
    }

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      location_t loc;
      loc = gimple_location (bi_call);
      fprintf (dump_file,
               "%s:%d: note: function call is shrink-wrapped"
               " into error conditions.\n",
               LOCATION_FILE (loc), LOCATION_LINE (loc));
    }
}
示例#22
0
static void
init_copy_prop (void)
{
  basic_block bb;

  copy_of = XCNEWVEC (prop_value_t, num_ssa_names);

  FOR_EACH_BB (bb)
    {
      gimple_stmt_iterator si;
      int depth = bb_loop_depth (bb);

      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.
	     ???  This doesn't make sense.  */
	  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);
	}

      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 (virtual_operand_p (def))
            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);
	}
    }
}
示例#23
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;
}
示例#24
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