RISC-V: Fix bugs of supporting AVL=REG (single-real-def) in VSETVL PASS

RISC-V: Fix bugs of supporting AVL=REG (single-real-def) in VSETVL PASS

gcc/ChangeLog:

	* config/riscv/riscv-vsetvl.cc (same_bb_and_before_p): Remove it.
	(real_insn_and_same_bb_p): New function.
	(same_bb_and_after_or_equal_p): Remove it.
	(before_p): New function.
	(reg_killed_by_bb_p): Ditto.
	(has_vsetvl_killed_avl_p): Ditto.
	(get_vl): Move location so that we can call it.
	(anticipatable_occurrence_p): Fix issue of AVL=REG support.
	(available_occurrence_p): Ditto.
	(dominate_probability_p): Remove it.
	(can_backward_propagate_p): Remove it.
	(get_all_nonphi_defs): New function.
	(get_all_predecessors): Ditto.
	(any_insn_in_bb_p): Ditto.
	(insert_vsetvl): Adjust AVL REG.
	(source_equal_p): New function.
	(extract_single_source): Ditto.
	(avl_info::single_source_equal_p): Ditto.
	(avl_info::operator==): Adjust for AVL=REG.
	(vl_vtype_info::same_avl_p): Ditto.
	(vector_insn_info::set_demand_info): Remove it.
	(vector_insn_info::compatible_p): Adjust for AVL=REG.
	(vector_insn_info::compatible_avl_p): New function.
	(vector_insn_info::merge): Adjust AVL=REG.
	(vector_insn_info::dump): Ditto.
	(pass_vsetvl::merge_successors): Remove it.
	(enum fusion_type): New enum.
	(pass_vsetvl::get_backward_fusion_type): New function.
	(pass_vsetvl::backward_demand_fusion): Adjust for AVL=REG.
	(pass_vsetvl::forward_demand_fusion): Ditto.
	(pass_vsetvl::demand_fusion): Ditto.
	(pass_vsetvl::prune_expressions): Ditto.
	(pass_vsetvl::compute_local_properties): Ditto.
	(pass_vsetvl::cleanup_vsetvls): Ditto.
	(pass_vsetvl::commit_vsetvls): Ditto.
	(pass_vsetvl::init): Ditto.
	* config/riscv/riscv-vsetvl.h (enum fusion_type): New enum.
	(enum merge_type): New enum.