* doc/md.texi: Document define_subst.
* gensupport.c (MAX_OPERANDS): New define.
(operand_data): New.
(match_operand_entries_in_pattern): New.
(used_operands_numbers): New.
(subst_true): New.
(subst_false): New.
(define_subst_queue): New.
(define_subst_tail): New.
(define_subst_attr_queue): New.
(define_subst_attr_tail): New.
(has_subst_attribute): New.
(subst_pattern_match): New.
(get_alternatives_number): New.
(alter_output_for_subst_insn): New.
(alter_attrs_for_subst_insn): New.
(process_substs_on_one_elem): New.
(subst_dup): New.
(process_define_subst): New.
(duplicate_alternatives): New.
(duplicate_each_alternative): New.
(constraints_handler_t): New typedef.
(alter_constraints): New.
(adjust_operands_numbers): New.
(replace_duplicating_operands_in_pattern): New.
(remove_from_queue): New.
(process_rtx): Handle define_subst and define_subst_attr.
(change_subst_attribute): New.
(alter_predicate_for_insn): Fix formatting.
(alter_attrs_for_insn): Likewise.
(alter_output_for_insn): Likewise.
(mark_operands_from_match_dup): New.
(mark_operands_used_in_match_dup): New.
(find_first_unused_number_of_operand): New.
(renumerate_operands_in_pattern): New.
(generate_match_dup): New.
(check_define_attr_duplicates): New.
(init_rtx_reader_args_cb): Add checking for duplicated attrs and
processing of define_subst.
(read_md_rtx): Handle define_subst.
* read-rtl.c (struct subst_attr_to_iter_mapping): New.
(substs): New global.
(apply_subst_iterator): New.
(bind_subst_iter_and_attr): New.
(find_subst_iter_by_attr): New.
(map_attr_string): Handle subst-iterators.
(add_condition_to_rtx): Handle define_subst.
(apply_iterators): Likewise.
(initialize_iterators): Likewise.
(add_define_attr_for_define_subst): New.
(add_define_subst_attr): New.
(read_subst_mapping): New.
(read_rtx): Handle define_subst_attr.
(read_rtx_code): Add subst-attributes recognition during reading of
strings.
* rtl.def (DEFINE_EXPAND): Add vector of attributes.
(DEFINE_SUBST): New.
(DEFINE_SUBST_ATTR): New.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193618 138bc75d-0d04-0410-961f-82ee72b054a4