* alias.c (get_alias_set): Add support for TYPE_REF_CAN_ALIAS_ALL.
	* c-common.c (handle_mode_attribute): Add extra arg to
	build_pointer_type_for_mode and build_reference_type_for_mode.
	* c-typeck.c (build_c_cast): Only look at TREE_CONSTANT_OVERFLOW
	for INTEGER_CST.
	* tree.c (build_pointer_type_for_mode): Add arg CAN_ALIAS_ALL.
	Chain pointers via TYPE_NEXT_PTR_TO.
	(build_reference_type_for_mode): Similarly.
	(build_type_no_quals): Add extra arg to build_pointer_type_for_mode
	and build_reference_type_for_mode.
	(tree_check4_failed): New function.
	* tree.h (TREE_CHECK4, PTR_OR_REF_CHECK): New macros.
	(TYPE_REF_CAN_ALIAS_ALL, TYPE_NEXT_PTR_TO, TYPE_NEXT_REF_TO): Likewise.
	(TREE_NO_UNSUED_WARNING, TREE_VIA_VIRTUAL, TREE_CONSTANT_OVERFLOW):
	Add check.

	* cp/typeck.c (build_c_cast): Only look at TREE_CONSTANT_OVERFLOW
	for INTEGER_CST.

	* ada/decl.c (gnat_to_gnu_entity, case E_Access_Type): Pass value
	of No_Strict_Aliasing to build_pointer_type_for_mode.
	* ada/utils.c (update_pointer_to): Walk pointer and ref chains.

From-SVN: r79873