Exemple #1
0
void
mark_exp_read (tree exp)
{
    if (exp == NULL)
        return;

    switch (TREE_CODE (exp))
    {
    case VAR_DECL:
    case PARM_DECL:
        DECL_READ_P (exp) = 1;
        break;
    case ARRAY_REF:
    case COMPONENT_REF:
    case MODIFY_EXPR:
    case REALPART_EXPR:
    case IMAGPART_EXPR:
CASE_CONVERT:
    case ADDR_EXPR:
    case INDIRECT_REF:
        mark_exp_read (TREE_OPERAND (exp, 0));
        break;
    case COMPOUND_EXPR:
        mark_exp_read (TREE_OPERAND (exp, 1));
        break;
    case COND_EXPR:
        if (TREE_OPERAND (exp, 1))
            mark_exp_read (TREE_OPERAND (exp, 1));
        if (TREE_OPERAND (exp, 2))
            mark_exp_read (TREE_OPERAND (exp, 2));
        break;
    default:
        break;
    }
}
Exemple #2
0
Fichier : expr.c Projet : Gd58/gcc
/* Called whenever the expression EXPR is used in an rvalue context.
   When REJECT_BUILTIN is true the expression is checked to make sure
   it doesn't make it possible to obtain the address of a GCC built-in
   function with no library fallback (or any of its bits, such as in
   a conversion to bool).  */
tree
mark_rvalue_use (tree expr,
		 location_t loc /* = UNKNOWN_LOCATION */,
		 bool reject_builtin /* = true */)
{
  if (reject_builtin && reject_gcc_builtin (expr, loc))
    return error_mark_node;

  mark_exp_read (expr);
  return expr;
}
Exemple #3
0
void
maybe_add_lambda_conv_op (tree type)
{
  bool nested = (cfun != NULL);
  bool nested_def = decl_function_context (TYPE_MAIN_DECL (type));
  tree callop = lambda_function (type);

  if (LAMBDA_EXPR_CAPTURE_LIST (CLASSTYPE_LAMBDA_EXPR (type)) != NULL_TREE)
    return;

  if (processing_template_decl)
    return;

  bool const generic_lambda_p
    = (DECL_TEMPLATE_INFO (callop)
    && DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (callop)) == callop);

  if (!generic_lambda_p && DECL_INITIAL (callop) == NULL_TREE)
    {
      /* If the op() wasn't instantiated due to errors, give up.  */
      gcc_assert (errorcount || sorrycount);
      return;
    }

  /* Non-template conversion operators are defined directly with build_call_a
     and using DIRECT_ARGVEC for arguments (including 'this').  Templates are
     deferred and the CALL is built in-place.  In the case of a deduced return
     call op, the decltype expression, DECLTYPE_CALL, used as a substitute for
     the return type is also built in-place.  The arguments of DECLTYPE_CALL in
     the return expression may differ in flags from those in the body CALL.  In
     particular, parameter pack expansions are marked PACK_EXPANSION_LOCAL_P in
     the body CALL, but not in DECLTYPE_CALL.  */

  vec<tree, va_gc> *direct_argvec = 0;
  tree decltype_call = 0, call = 0;
  tree fn_result = TREE_TYPE (TREE_TYPE (callop));

  if (generic_lambda_p)
    {
      /* Prepare the dependent member call for the static member function
	 '_FUN' and, potentially, prepare another call to be used in a decltype
	 return expression for a deduced return call op to allow for simple
	 implementation of the conversion operator.  */

      tree instance = build_nop (type, null_pointer_node);
      tree objfn = build_min (COMPONENT_REF, NULL_TREE,
			      instance, DECL_NAME (callop), NULL_TREE);
      int nargs = list_length (DECL_ARGUMENTS (callop)) - 1;

      call = prepare_op_call (objfn, nargs);
      if (type_uses_auto (fn_result))
	decltype_call = prepare_op_call (objfn, nargs);
    }
  else
    {
      direct_argvec = make_tree_vector ();
      direct_argvec->quick_push (build1 (NOP_EXPR,
					 TREE_TYPE (DECL_ARGUMENTS (callop)),
					 null_pointer_node));
    }

  /* Copy CALLOP's argument list (as per 'copy_list') as FN_ARGS in order to
     declare the static member function "_FUN" below.  For each arg append to
     DIRECT_ARGVEC (for the non-template case) or populate the pre-allocated
     call args (for the template case).  If a parameter pack is found, expand
     it, flagging it as PACK_EXPANSION_LOCAL_P for the body call.  */

  tree fn_args = NULL_TREE;
  {
    int ix = 0;
    tree src = DECL_CHAIN (DECL_ARGUMENTS (callop));
    tree tgt;

    while (src)
      {
	tree new_node = copy_node (src);

	if (!fn_args)
	  fn_args = tgt = new_node;
	else
	  {
	    TREE_CHAIN (tgt) = new_node;
	    tgt = new_node;
	  }

	mark_exp_read (tgt);

	if (generic_lambda_p)
	  {
	    if (DECL_PACK_P (tgt))
	      {
		tree a = make_pack_expansion (tgt);
		if (decltype_call)
		  CALL_EXPR_ARG (decltype_call, ix) = copy_node (a);
		PACK_EXPANSION_LOCAL_P (a) = true;
		CALL_EXPR_ARG (call, ix) = a;
	      }
	    else
	      {
		tree a = convert_from_reference (tgt);
		CALL_EXPR_ARG (call, ix) = a;
		if (decltype_call)
		  CALL_EXPR_ARG (decltype_call, ix) = copy_node (a);
	      }
	    ++ix;
	  }
	else
	  vec_safe_push (direct_argvec, tgt);

	src = TREE_CHAIN (src);
      }
  }


  if (generic_lambda_p)
    {
      if (decltype_call)
	{
	  ++processing_template_decl;
	  fn_result = finish_decltype_type
	    (decltype_call, /*id_expression_or_member_access_p=*/false,
	     tf_warning_or_error);
	  --processing_template_decl;
	}
    }
  else
    call = build_call_a (callop,
			 direct_argvec->length (),
			 direct_argvec->address ());

  CALL_FROM_THUNK_P (call) = 1;

  tree stattype = build_function_type (fn_result, FUNCTION_ARG_CHAIN (callop));

  /* First build up the conversion op.  */

  tree rettype = build_pointer_type (stattype);
  tree name = mangle_conv_op_name_for_type (rettype);
  tree thistype = cp_build_qualified_type (type, TYPE_QUAL_CONST);
  tree fntype = build_method_type_directly (thistype, rettype, void_list_node);
  tree convfn = build_lang_decl (FUNCTION_DECL, name, fntype);
  tree fn = convfn;
  DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (callop);

  if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_pfn
      && DECL_ALIGN (fn) < 2 * BITS_PER_UNIT)
    DECL_ALIGN (fn) = 2 * BITS_PER_UNIT;

  SET_OVERLOADED_OPERATOR_CODE (fn, TYPE_EXPR);
  grokclassfn (type, fn, NO_SPECIAL);
  set_linkage_according_to_type (type, fn);
  rest_of_decl_compilation (fn, toplevel_bindings_p (), at_eof);
  DECL_IN_AGGR_P (fn) = 1;
  DECL_ARTIFICIAL (fn) = 1;
  DECL_NOT_REALLY_EXTERN (fn) = 1;
  DECL_DECLARED_INLINE_P (fn) = 1;
  DECL_ARGUMENTS (fn) = build_this_parm (fntype, TYPE_QUAL_CONST);
  if (nested_def)
    DECL_INTERFACE_KNOWN (fn) = 1;

  if (generic_lambda_p)
    fn = add_inherited_template_parms (fn, DECL_TI_TEMPLATE (callop));

  add_method (type, fn, NULL_TREE);

  /* Generic thunk code fails for varargs; we'll complain in mark_used if
     the conversion op is used.  */
  if (varargs_function_p (callop))
    {
      DECL_DELETED_FN (fn) = 1;
      return;
    }

  /* Now build up the thunk to be returned.  */

  name = get_identifier ("_FUN");
  tree statfn = build_lang_decl (FUNCTION_DECL, name, stattype);
  fn = statfn;
  DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (callop);
  if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_pfn
      && DECL_ALIGN (fn) < 2 * BITS_PER_UNIT)
    DECL_ALIGN (fn) = 2 * BITS_PER_UNIT;
  grokclassfn (type, fn, NO_SPECIAL);
  set_linkage_according_to_type (type, fn);
  rest_of_decl_compilation (fn, toplevel_bindings_p (), at_eof);
  DECL_IN_AGGR_P (fn) = 1;
  DECL_ARTIFICIAL (fn) = 1;
  DECL_NOT_REALLY_EXTERN (fn) = 1;
  DECL_DECLARED_INLINE_P (fn) = 1;
  DECL_STATIC_FUNCTION_P (fn) = 1;
  DECL_ARGUMENTS (fn) = fn_args;
  for (tree arg = fn_args; arg; arg = DECL_CHAIN (arg))
    {
      /* Avoid duplicate -Wshadow warnings.  */
      DECL_NAME (arg) = NULL_TREE;
      DECL_CONTEXT (arg) = fn;
    }
  if (nested_def)
    DECL_INTERFACE_KNOWN (fn) = 1;

  if (generic_lambda_p)
    fn = add_inherited_template_parms (fn, DECL_TI_TEMPLATE (callop));

  add_method (type, fn, NULL_TREE);

  if (nested)
    push_function_context ();
  else
    /* Still increment function_depth so that we don't GC in the
       middle of an expression.  */
    ++function_depth;

  /* Generate the body of the thunk.  */

  start_preparsed_function (statfn, NULL_TREE,
			    SF_PRE_PARSED | SF_INCLASS_INLINE);
  if (DECL_ONE_ONLY (statfn))
    {
      /* Put the thunk in the same comdat group as the call op.  */
      cgraph_node::get_create (statfn)->add_to_same_comdat_group
	(cgraph_node::get_create (callop));
    }
  tree body = begin_function_body ();
  tree compound_stmt = begin_compound_stmt (0);
  if (!generic_lambda_p)
    {
      set_flags_from_callee (call);
      if (MAYBE_CLASS_TYPE_P (TREE_TYPE (call)))
	call = build_cplus_new (TREE_TYPE (call), call, tf_warning_or_error);
    }
  call = convert_from_reference (call);
  finish_return_stmt (call);

  finish_compound_stmt (compound_stmt);
  finish_function_body (body);

  fn = finish_function (/*inline*/2);
  if (!generic_lambda_p)
    expand_or_defer_fn (fn);

  /* Generate the body of the conversion op.  */

  start_preparsed_function (convfn, NULL_TREE,
			    SF_PRE_PARSED | SF_INCLASS_INLINE);
  body = begin_function_body ();
  compound_stmt = begin_compound_stmt (0);

  /* decl_needed_p needs to see that it's used.  */
  TREE_USED (statfn) = 1;
  finish_return_stmt (decay_conversion (statfn, tf_warning_or_error));

  finish_compound_stmt (compound_stmt);
  finish_function_body (body);

  fn = finish_function (/*inline*/2);
  if (!generic_lambda_p)
    expand_or_defer_fn (fn);

  if (nested)
    pop_function_context ();
  else
    --function_depth;
}
Exemple #4
0
Fichier : expr.c Projet : Gd58/gcc
tree
mark_type_use (tree expr)
{
  mark_exp_read (expr);
  return expr;
}
Exemple #5
0
Fichier : expr.c Projet : Gd58/gcc
tree
mark_lvalue_use (tree expr)
{
  mark_exp_read (expr);
  return expr;
}
Exemple #6
0
tree
convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
{
  if (expr == error_mark_node
      || TREE_TYPE (expr) == error_mark_node)
    return error_mark_node;

  if (implicit == ICV_CAST)
    mark_exp_read (expr);
  else
    {
      tree exprv = expr;

      while (TREE_CODE (exprv) == COMPOUND_EXPR)
	exprv = TREE_OPERAND (exprv, 1);
      if (DECL_P (exprv)
	  || handled_component_p (exprv)
	  || TREE_CODE (exprv) == INDIRECT_REF)
	/* Expr is not being 'used' here, otherwise we whould have
	   called mark_{rl}value_use use here, which would have in turn
	   called mark_exp_read.  Rather, we call mark_exp_read directly
	   to avoid some warnings when
	   -Wunused-but-set-{variable,parameter} is in effect.  */
	mark_exp_read (exprv);
    }

  if (!TREE_TYPE (expr))
    return expr;
  if (invalid_nonstatic_memfn_p (expr, complain))
    return error_mark_node;
  if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
    {
      if (complain & tf_error)
        error ("pseudo-destructor is not called");
      return error_mark_node;
    }
  if (VOID_TYPE_P (TREE_TYPE (expr)))
    return expr;
  switch (TREE_CODE (expr))
    {
    case COND_EXPR:
      {
	/* The two parts of a cond expr might be separate lvalues.  */
	tree op1 = TREE_OPERAND (expr,1);
	tree op2 = TREE_OPERAND (expr,2);
	bool side_effects = TREE_SIDE_EFFECTS (op1) || TREE_SIDE_EFFECTS (op2);
	tree new_op1, new_op2;
	if (implicit != ICV_CAST && !side_effects)
	  {
	    new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
	    new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
	  }
	else
	  {
	    new_op1 = convert_to_void (op1, ICV_CAST, complain);
	    new_op2 = convert_to_void (op2, ICV_CAST, complain);
	  }

	expr = build3 (COND_EXPR, TREE_TYPE (new_op1),
		       TREE_OPERAND (expr, 0), new_op1, new_op2);
	break;
      }

    case COMPOUND_EXPR:
      {
	/* The second part of a compound expr contains the value.  */
	tree op1 = TREE_OPERAND (expr,1);
	tree new_op1;
	if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
	  new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
	else
	  new_op1 = convert_to_void (op1, ICV_CAST, complain);

	if (new_op1 != op1)
	  {
	    tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
			     TREE_OPERAND (expr, 0), new_op1);
	    expr = t;
	  }

	break;
      }

    case NON_LVALUE_EXPR:
    case NOP_EXPR:
      /* These have already decayed to rvalue.  */
      break;

    case CALL_EXPR:   /* We have a special meaning for volatile void fn().  */
      break;

    case INDIRECT_REF:
      {
	tree type = TREE_TYPE (expr);
	int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
			   == REFERENCE_TYPE;
	int is_volatile = TYPE_VOLATILE (type);
	int is_complete = COMPLETE_TYPE_P (complete_type (type));

	/* Can't load the value if we don't know the type.  */
	if (is_volatile && !is_complete)
          {
            if (complain & tf_warning)
	      switch (implicit)
		{
	      	  case ICV_CAST:
		    warning (0, "conversion to void will not access "
				"object of incomplete type %qT", type);
		    break;
		  case ICV_SECOND_OF_COND:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in second operand "
				"of conditional expression", type);
		    break;
		  case ICV_THIRD_OF_COND:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in third operand "
				"of conditional expression", type);
		    break;
		  case ICV_RIGHT_OF_COMMA:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in right operand of "
				"comma operator", type);
		    break;
		  case ICV_LEFT_OF_COMMA:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in left operand of "
				"comma operator", type);
		    break;
		  case ICV_STATEMENT:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in statement", type);
		     break;
		  case ICV_THIRD_IN_FOR:
		    warning (0, "indirection will not access object of "
				"incomplete type %qT in for increment "
				"expression", type);
		    break;
		  default:
		    gcc_unreachable ();
		}
          }
	/* Don't load the value if this is an implicit dereference, or if
	   the type needs to be handled by ctors/dtors.  */
	else if (is_volatile && is_reference)
          {
            if (complain & tf_warning)
	      switch (implicit)
		{
	      	  case ICV_CAST:
		    warning (0, "conversion to void will not access "
				"object of type %qT", type);
		    break;
		  case ICV_SECOND_OF_COND:
		    warning (0, "implicit dereference will not access object "
				"of type %qT in second operand of "
				"conditional expression", type);
		    break;
		  case ICV_THIRD_OF_COND:
		    warning (0, "implicit dereference will not access object "
		  	      	"of type %qT in third operand of "
				"conditional expression", type);
		    break;
		  case ICV_RIGHT_OF_COMMA:
		    warning (0, "implicit dereference will not access object "
		    		"of type %qT in right operand of "
				"comma operator", type);
		    break;
		  case ICV_LEFT_OF_COMMA:
		    warning (0, "implicit dereference will not access object "
		    		"of type %qT in left operand of comma operator",
			     type);
		    break;
		  case ICV_STATEMENT:
		    warning (0, "implicit dereference will not access object "
		     		"of type %qT in statement",  type);
		     break;
		  case ICV_THIRD_IN_FOR:
		    warning (0, "implicit dereference will not access object "
		    		"of type %qT in for increment expression",
			     type);
		    break;
		  default:
		    gcc_unreachable ();
		}
          }
	else if (is_volatile && TREE_ADDRESSABLE (type))
	  {
	    if (complain & tf_warning)
	      switch (implicit)
		{
	      	  case ICV_CAST:
		    warning (0, "conversion to void will not access "
				"object of non-trivially-copyable type %qT",
			     type);
		    break;
		  case ICV_SECOND_OF_COND:
		    warning (0, "indirection will not access object of "
				"non-trivially-copyable type %qT in second "
				"operand of conditional expression", type);
		    break;
		  case ICV_THIRD_OF_COND:
		    warning (0, "indirection will not access object of "
		  	      	"non-trivially-copyable type %qT in third "
				"operand of conditional expression", type);
		    break;
		  case ICV_RIGHT_OF_COMMA:
		    warning (0, "indirection will not access object of "
		    		"non-trivially-copyable type %qT in right "
				"operand of comma operator", type);
		    break;
		  case ICV_LEFT_OF_COMMA:
		    warning (0, "indirection will not access object of "
		    		"non-trivially-copyable type %qT in left "
				"operand of comma operator", type);
		    break;
		  case ICV_STATEMENT:
		    warning (0, "indirection will not access object of "
		     		"non-trivially-copyable type %qT in statement",
			      type);
		     break;
		  case ICV_THIRD_IN_FOR:
		    warning (0, "indirection will not access object of "
		    		"non-trivially-copyable type %qT in for "
				"increment expression", type);
		    break;
		  default:
		    gcc_unreachable ();
		}
	  }
	if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
          {
            /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
               operation is stripped off. Note that we don't warn about
               - an expression with TREE_NO_WARNING set. (For an example of
                 such expressions, see build_over_call in call.c.)
               - automatic dereferencing of references, since the user cannot
                 control it. (See also warn_if_unused_value() in stmt.c.)  */
            if (warn_unused_value
		&& implicit != ICV_CAST
                && (complain & tf_warning)
                && !TREE_NO_WARNING (expr)
                && !is_reference)
              warning (OPT_Wunused_value, "value computed is not used");
            expr = TREE_OPERAND (expr, 0);
          }

	break;
      }

    case VAR_DECL:
      {
	/* External variables might be incomplete.  */
	tree type = TREE_TYPE (expr);
	int is_complete = COMPLETE_TYPE_P (complete_type (type));

	if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
	  switch (implicit)
	    {
	      case ICV_CAST:
		warning (0, "conversion to void will not access "
			    "object %qE of incomplete type %qT", expr, type);
		break;
	      case ICV_SECOND_OF_COND:
	        warning (0, "variable %qE of incomplete type %qT will not "
			    "be accessed in second operand of "
			    "conditional expression", expr, type);
		break;
	      case ICV_THIRD_OF_COND:
	        warning (0, "variable %qE of incomplete type %qT will not "
			    "be accessed in third operand of "
			    "conditional expression", expr, type);
		break;
	      case ICV_RIGHT_OF_COMMA:
	        warning (0, "variable %qE of incomplete type %qT will not "
			    "be accessed in right operand of comma operator",
			 expr, type);
		break;
	      case ICV_LEFT_OF_COMMA:
	        warning (0, "variable %qE of incomplete type %qT will not "
			    "be accessed in left operand of comma operator",
			 expr, type);
		break;
	      case ICV_STATEMENT:
	        warning (0, "variable %qE of incomplete type %qT will not "
		            "be accessed in statement", expr, type);
		break;
	      case ICV_THIRD_IN_FOR:
	        warning (0, "variable %qE of incomplete type %qT will not "
			    "be accessed in for increment expression",
		         expr, type);
		break;
	      default:
	        gcc_unreachable ();
	    }

	break;
      }

    case TARGET_EXPR:
      /* Don't bother with the temporary object returned from a function if
	 we don't use it and don't need to destroy it.  We'll still
	 allocate space for it in expand_call or declare_return_variable,
	 but we don't need to track it through all the tree phases.  */
      if (TARGET_EXPR_IMPLICIT_P (expr)
	  && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
	{
	  tree init = TARGET_EXPR_INITIAL (expr);
	  if (TREE_CODE (init) == AGGR_INIT_EXPR
	      && !AGGR_INIT_VIA_CTOR_P (init))
	    {
	      tree fn = AGGR_INIT_EXPR_FN (init);
	      expr = build_call_array_loc (input_location,
					   TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
					   fn,
					   aggr_init_expr_nargs (init),
					   AGGR_INIT_EXPR_ARGP (init));
	    }
	}
      break;

    default:;
    }
  expr = resolve_nondeduced_context (expr);
  {
    tree probe = expr;

    if (TREE_CODE (probe) == ADDR_EXPR)
      probe = TREE_OPERAND (expr, 0);
    if (type_unknown_p (probe))
      {
	/* [over.over] enumerates the places where we can take the address
	   of an overloaded function, and this is not one of them.  */
	if (complain & tf_error)
	  switch (implicit)
	    {
	      case ICV_CAST:
		error ("conversion to void "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_SECOND_OF_COND:
		error ("second operand of conditional expression "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_THIRD_OF_COND:
		error ("third operand of conditional expression "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_RIGHT_OF_COMMA:
		error ("right operand of comma operator "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_LEFT_OF_COMMA:
		error ("left operand of comma operator "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_STATEMENT:
		error ("statement "
		       "cannot resolve address of overloaded function");
		break;
	      case ICV_THIRD_IN_FOR:
		error ("for increment expression "
		       "cannot resolve address of overloaded function");
		break;
	    }
	else
	  return error_mark_node;
	expr = void_zero_node;
      }
    else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
      {
	/* Only warn when there is no &.  */
	if (complain & tf_warning)
	  switch (implicit)
	    {
	      case ICV_SECOND_OF_COND:
	        warning (OPT_Waddress,
			 "second operand of conditional expression "
			 "is a reference, not call, to function %qE", expr);
		break;
	      case ICV_THIRD_OF_COND:
	        warning (OPT_Waddress,
			 "third operand of conditional expression "
			 "is a reference, not call, to function %qE", expr);
		break;
	      case ICV_RIGHT_OF_COMMA:
	        warning (OPT_Waddress,
			 "right operand of comma operator "
			 "is a reference, not call, to function %qE", expr);
		break;
	      case ICV_LEFT_OF_COMMA:
	        warning (OPT_Waddress,
			 "left operand of comma operator "
			 "is a reference, not call, to function %qE", expr);
		break;
	      case ICV_STATEMENT:
	        warning (OPT_Waddress,
			 "statement is a reference, not call, to function %qE",
			 expr);
		break;
	      case ICV_THIRD_IN_FOR:
	        warning (OPT_Waddress,
			 "for increment expression "
			 "is a reference, not call, to function %qE", expr);
		break;
	      default:
	        gcc_unreachable ();
	    }

	if (TREE_CODE (expr) == COMPONENT_REF)
	  expr = TREE_OPERAND (expr, 0);
      }
  }

  if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
    {
      if (implicit != ICV_CAST
	  && warn_unused_value
	  && !TREE_NO_WARNING (expr)
	  && !processing_template_decl)
	{
	  /* The middle end does not warn about expressions that have
	     been explicitly cast to void, so we must do so here.  */
	  if (!TREE_SIDE_EFFECTS (expr)) {
            if (complain & tf_warning)
	      switch (implicit)
		{
		  case ICV_SECOND_OF_COND:
		    warning (OPT_Wunused_value,
			     "second operand of conditional expression has no effect");
		    break;
		  case ICV_THIRD_OF_COND:
		    warning (OPT_Wunused_value,
		    	     "third operand of conditional expression has no effect");
		    break;
		  case ICV_RIGHT_OF_COMMA:
		    warning (OPT_Wunused_value,
		    	     "right operand of comma operator has no effect");
		    break;
		  case ICV_LEFT_OF_COMMA:
		    warning (OPT_Wunused_value,
		    	     "left operand of comma operator has no effect");
		    break;
		  case ICV_STATEMENT:
		    warning (OPT_Wunused_value,
		    	     "statement has no effect");
		    break;
		  case ICV_THIRD_IN_FOR:
		    warning (OPT_Wunused_value,
		    	     "for increment expression has no effect");
		    break;
		  default:
		    gcc_unreachable ();
		}
          }
	  else
	    {
	      tree e;
	      enum tree_code code;
	      enum tree_code_class tclass;

	      e = expr;
	      /* We might like to warn about (say) "(int) f()", as the
		 cast has no effect, but the compiler itself will
		 generate implicit conversions under some
		 circumstances.  (For example a block copy will be
		 turned into a call to "__builtin_memcpy", with a
		 conversion of the return value to an appropriate
		 type.)  So, to avoid false positives, we strip
		 conversions.  Do not use STRIP_NOPs because it will
		 not strip conversions to "void", as that is not a
		 mode-preserving conversion.  */
	      while (TREE_CODE (e) == NOP_EXPR)
		e = TREE_OPERAND (e, 0);

	      code = TREE_CODE (e);
	      tclass = TREE_CODE_CLASS (code);
	      if ((tclass == tcc_comparison
		   || tclass == tcc_unary
		   || (tclass == tcc_binary
		       && !(code == MODIFY_EXPR
			    || code == INIT_EXPR
			    || code == PREDECREMENT_EXPR
			    || code == PREINCREMENT_EXPR
			    || code == POSTDECREMENT_EXPR
			    || code == POSTINCREMENT_EXPR)))
                  && (complain & tf_warning))
		warning (OPT_Wunused_value, "value computed is not used");
	    }
	}
      expr = build1 (CONVERT_EXPR, void_type_node, expr);
    }
  if (! TREE_SIDE_EFFECTS (expr))
    expr = void_zero_node;
  return expr;
}