RISC-V: Refactor and clean emit_{vlmax,nonvlmax}_xxx functions

RISC-V: Refactor and clean emit_{vlmax,nonvlmax}_xxx functions

This patch refactor the code of emit_{vlmax,nonvlmax}_xxx functions.
These functions are used to generate RVV insn. There are currently 31
such functions and a few duplicates. The reason so many functions are
needed is because there are more types of RVV instructions. There are
patterns that don't have mask operand, patterns that don't have merge
operand, and patterns that don't need a tail policy operand, etc.

Previously there was the insn_type enum, but it's value was just used
to indicate how many operands were passed in by caller. The rest of
the operands information is scattered throughout these functions.
For example, emit_vlmax_fp_insn indicates that a rounding mode operand
of FRM_DYN should also be passed, emit_vlmax_merge_insn means that
there is no mask operand or mask policy operand.

I introduced a new enum insn_flags to indicate some properties of these
RVV patterns. These insn_flags are then used to define insn_type enum.
For example for the defintion of WIDEN_TERNARY_OP:

  WIDEN_TERNARY_OP = HAS_DEST_P | HAS_MASK_P | USE_ALL_TRUES_MASK_P
                       | TDEFAULT_POLICY_P | MDEFAULT_POLICY_P | TERNARY_OP_P,

This flags mean the RVV pattern has no merge operand. This flags only apply
to vwmacc instructions. After defining the desired insn_type, all the
emit_{vlmax,nonvlmax}_xxx functions are unified into three functions:

  emit_vlmax_insn (icode, insn_flags, ops);
  emit_nonvlmax_insn (icode, insn_flags, ops, vl);
  emit_vlmax_insn_lra (icode, insn_flags, ops, vl);

Then user can select the appropriate insn_type and the appropriate emit_xxx
function for RVV patterns generation as needed.

gcc/ChangeLog:

	* config/riscv/autovec-opt.md: Adjust.
	* config/riscv/autovec-vls.md: Ditto.
	* config/riscv/autovec.md: Ditto.
	* config/riscv/riscv-protos.h (enum insn_type): Add insn_type.
	(enum insn_flags): Add insn flags.
	(emit_vlmax_insn): Adjust.
	(emit_vlmax_fp_insn): Delete.
	(emit_vlmax_ternary_insn): Delete.
	(emit_vlmax_fp_ternary_insn): Delete.
	(emit_nonvlmax_insn): Adjust.
	(emit_vlmax_slide_insn): Delete.
	(emit_nonvlmax_slide_tu_insn): Delete.
	(emit_vlmax_merge_insn): Delete.
	(emit_vlmax_cmp_insn): Delete.
	(emit_vlmax_cmp_mu_insn): Delete.
	(emit_vlmax_masked_mu_insn): Delete.
	(emit_scalar_move_insn): Delete.
	(emit_nonvlmax_integer_move_insn): Delete.
	(emit_vlmax_insn_lra): Add.
	* config/riscv/riscv-v.cc (get_mask_mode_from_insn_flags): New.
	(emit_vlmax_insn): Adjust.
	(emit_nonvlmax_insn): Adjust.
	(emit_vlmax_insn_lra): Add.
	(emit_vlmax_fp_insn): Delete.
	(emit_vlmax_ternary_insn): Delete.
	(emit_vlmax_fp_ternary_insn): Delete.
	(emit_vlmax_slide_insn): Delete.
	(emit_nonvlmax_slide_tu_insn): Delete.
	(emit_nonvlmax_slide_insn): Delete.
	(emit_vlmax_merge_insn): Delete.
	(emit_vlmax_cmp_insn): Delete.
	(emit_vlmax_cmp_mu_insn): Delete.
	(emit_vlmax_masked_insn): Delete.
	(emit_nonvlmax_masked_insn): Delete.
	(emit_vlmax_masked_store_insn): Delete.
	(emit_nonvlmax_masked_store_insn): Delete.
	(emit_vlmax_masked_mu_insn): Delete.
	(emit_vlmax_masked_fp_mu_insn): Delete.
	(emit_nonvlmax_tu_insn): Delete.
	(emit_nonvlmax_fp_tu_insn): Delete.
	(emit_nonvlmax_tumu_insn): Delete.
	(emit_nonvlmax_fp_tumu_insn): Delete.
	(emit_scalar_move_insn): Delete.
	(emit_cpop_insn): Delete.
	(emit_vlmax_integer_move_insn): Delete.
	(emit_nonvlmax_integer_move_insn): Delete.
	(emit_vlmax_gather_insn): Delete.
	(emit_vlmax_masked_gather_mu_insn): Delete.
	(emit_vlmax_compress_insn): Delete.
	(emit_nonvlmax_compress_insn): Delete.
	(emit_vlmax_reduction_insn): Delete.
	(emit_vlmax_fp_reduction_insn): Delete.
	(emit_nonvlmax_fp_reduction_insn): Delete.
	(expand_vec_series): Adjust.
	(expand_const_vector): Adjust.
	(legitimize_move): Adjust.
	(sew64_scalar_helper): Adjust.
	(expand_tuple_move): Adjust.
	(expand_vector_init_insert_elems): Adjust.
	(expand_vector_init_merge_repeating_sequence): Adjust.
	(expand_vec_cmp): Adjust.
	(expand_vec_cmp_float): Adjust.
	(expand_vec_perm): Adjust.
	(shuffle_merge_patterns): Adjust.
	(shuffle_compress_patterns): Adjust.
	(shuffle_decompress_patterns): Adjust.
	(expand_load_store): Adjust.
	(expand_cond_len_op): Adjust.
	(expand_cond_len_unop): Adjust.
	(expand_cond_len_binop): Adjust.
	(expand_gather_scatter): Adjust.
	(expand_cond_len_ternop): Adjust.
	(expand_reduction): Adjust.
	(expand_lanes_load_store): Adjust.
	(expand_fold_extract_last): Adjust.
	* config/riscv/riscv.cc (vector_zero_call_used_regs): Adjust.
	* config/riscv/vector.md: Adjust.