C++ (Cpp) tree_could_trap_p Examples

Example #1

static void
check_lhs_var (funct_state local, tree t)
{
  /* Memcmp and strlen can both trap and they are declared pure.
     Which seems to imply that we can apply the same rule here.  */
  if (tree_could_trap_p (t)
      && local->pure_const_state == IPA_CONST)
    local->pure_const_state = IPA_PURE;
    
  check_tree(local, t, true);
}

Example #2

static void
check_rhs_var (funct_state local, tree t)
{
  look_for_address_of (local, t);

  /* Memcmp and strlen can both trap and they are declared pure.  */
  if (tree_could_trap_p (t)
      && local->pure_const_state == IPA_CONST)
    local->pure_const_state = IPA_PURE;

  check_tree(local, t, false);
}

Example #3

File: tree-ssa-loop-im.c Project: mdezeeuw/mb-rvex

enum move_pos
movement_possibility (tree stmt)
{
  tree lhs, rhs;

  if (flag_unswitch_loops
      && TREE_CODE (stmt) == COND_EXPR)
    {
      /* If we perform unswitching, force the operands of the invariant
	 condition to be moved out of the loop.  */
      return MOVE_POSSIBLE;
    }

  if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
    return MOVE_IMPOSSIBLE;

  if (stmt_ends_bb_p (stmt))
    return MOVE_IMPOSSIBLE;

  if (stmt_ann (stmt)->has_volatile_ops)
    return MOVE_IMPOSSIBLE;

  lhs = GIMPLE_STMT_OPERAND (stmt, 0);
  if (TREE_CODE (lhs) == SSA_NAME
      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
    return MOVE_IMPOSSIBLE;

  rhs = GIMPLE_STMT_OPERAND (stmt, 1);

  if (TREE_SIDE_EFFECTS (rhs)
      || tree_could_throw_p (rhs))
    return MOVE_IMPOSSIBLE;

  if (TREE_CODE (lhs) != SSA_NAME
      || tree_could_trap_p (rhs))
    return MOVE_PRESERVE_EXECUTION;

  if (get_call_expr_in (stmt))
    {
      /* While pure or const call is guaranteed to have no side effects, we
	 cannot move it arbitrarily.  Consider code like

	 char *s = something ();

	 while (1)
	   {
	     if (s)
	       t = strlen (s);
	     else
	       t = 0;
	   }

	 Here the strlen call cannot be moved out of the loop, even though
	 s is invariant.  In addition to possibly creating a call with
	 invalid arguments, moving out a function call that is not executed
	 may cause performance regressions in case the call is costly and
	 not executed at all.  */
      return MOVE_PRESERVE_EXECUTION;
    }
  return MOVE_POSSIBLE;
}