Beispiel #1
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);
	}
    }
}
Beispiel #2
0
static inline prop_value_t *
get_copy_of_val (tree var)
{
  prop_value_t *val = &copy_of[SSA_NAME_VERSION (var)];

  if (val->value == NULL_TREE
      && !stmt_may_generate_copy (SSA_NAME_DEF_STMT (var)))
    {
      /* If the variable will never generate a useful copy relation,
	 make it its own copy.  */
      val->value = var;
    }

  return val;
}
Beispiel #3
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);
	}
    }
}
Beispiel #4
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;
	}
    }
}