RISC-V: Finalize VSETVL PASS implementation

RISC-V: Finalize VSETVL PASS implementation

gcc/ChangeLog:

	* config/riscv/riscv-vsetvl.cc (vsetvl_insn_p): Add condition to avoid ICE.
	(vsetvl_discard_result_insn_p): New function.
	(reg_killed_by_bb_p): rename to find_reg_killed_by.
	(find_reg_killed_by): New name.
	(get_vl): allow it to be called by more functions.
	(has_vsetvl_killed_avl_p): Add condition.
	(get_avl): allow it to be called by more functions.
	(insn_should_be_added_p): New function.
	(get_all_nonphi_defs): Refine function.
	(get_all_sets): Ditto.
	(get_same_bb_set): New function.
	(any_insn_in_bb_p): Ditto.
	(any_set_in_bb_p): Ditto.
	(get_vl_vtype_info): Add VLMAX forward optimization.
	(source_equal_p): Fix issues.
	(extract_single_source): Refine.
	(avl_info::multiple_source_equal_p): New function.
	(avl_info::operator==): Adjust for final version.
	(vl_vtype_info::operator==): Ditto.
	(vl_vtype_info::same_avl_p): Ditto.
	(vector_insn_info::parse_insn): Ditto.
	(vector_insn_info::available_p): New function.
	(vector_insn_info::merge): Adjust for final version.
	(vector_insn_info::dump): Add hard_empty.
	(pass_vsetvl::hard_empty_block_p): New function.
	(pass_vsetvl::backward_demand_fusion): Adjust for final version.
	(pass_vsetvl::forward_demand_fusion): Ditto.
	(pass_vsetvl::demand_fusion): Ditto.
	(pass_vsetvl::cleanup_illegal_dirty_blocks): New function.
	(pass_vsetvl::compute_local_properties): Adjust for final version.
	(pass_vsetvl::can_refine_vsetvl_p): Ditto.
	(pass_vsetvl::refine_vsetvls): Ditto.
	(pass_vsetvl::commit_vsetvls): Ditto.
	(pass_vsetvl::propagate_avl): New function.
	(pass_vsetvl::lazy_vsetvl): Adjust for new version.
	* config/riscv/riscv-vsetvl.h (enum def_type): New enum.