aarch64: add SVE2 FP8 multiply accumulate intrinsics

aarch64: add SVE2 FP8 multiply accumulate intrinsics

This patch adds support for the following intrinsics:
- svmlalb[_f16_mf8]_fpm
- svmlalb[_n_f16_mf8]_fpm
- svmlalt[_f16_mf8]_fpm
- svmlalt[_n_f16_mf8]_fpm
- svmlalb_lane[_f16_mf8]_fpm
- svmlalt_lane[_f16_mf8]_fpm
- svmlallbb[_f32_mf8]_fpm
- svmlallbb[_n_f32_mf8]_fpm
- svmlallbt[_f32_mf8]_fpm
- svmlallbt[_n_f32_mf8]_fpm
- svmlalltb[_f32_mf8]_fpm
- svmlalltb[_n_f32_mf8]_fpm
- svmlalltt[_f32_mf8]_fpm
- svmlalltt[_n_f32_mf8]_fpm
- svmlallbb_lane[_f32_mf8]_fpm
- svmlallbt_lane[_f32_mf8]_fpm
- svmlalltb_lane[_f32_mf8]_fpm
- svmlalltt_lane[_f32_mf8]_fpm

These are available under a combination of the FP8FMA and SVE2 features.
Alternatively under the SSVE_FP8FMA feature under streaming mode.

gcc/
	* config/aarch64/aarch64-option-extensions.def
	(fp8fma, ssve-fp8fma): Add new options.
	* config/aarch64/aarch64-sve-builtins-functions.h
	(unspec_based_function_base): Add unspec_for_mfp8.
	(unspec_for): Return unspec_for_mfp8 on fpm-using cases.
	(sme_1mode_function): Fix call to parent ctor.
	(sme_2mode_function_t): Likewise.
	(unspec_based_mla_function, unspec_based_mla_lane_function): Handle
	fpm-using cases.
	* config/aarch64/aarch64-sve-builtins-shapes.cc
	(parse_element_type): Treat M as TYPE_SUFFIX_mf8
	(ternary_mfloat8_lane_def): Add new class.
	(ternary_mfloat8_opt_n_def): Likewise.
	(ternary_mfloat8_lane): Add new shape.
	(ternary_mfloat8_opt_n): Likewise.
	* config/aarch64/aarch64-sve-builtins-shapes.h
	(ternary_mfloat8_lane, ternary_mfloat8_opt_n): Declare.
	* config/aarch64/aarch64-sve-builtins-sve2.cc
	(svmlalb_lane, svmlalb, svmlalt_lane, svmlalt): Update definitions
	with mfloat8_t unspec in ctor.
	(svmlallbb_lane, svmlallbb, svmlallbt_lane, svmlallbt, svmlalltb_lane,
	svmlalltb, svmlalltt_lane, svmlalltt, svmlal_impl): Add new FUNCTIONs.
	(svqrshr, svqrshrn, svqrshru, svqrshrun): Update definitions with
	nop mfloat8 unspec in ctor.
	* config/aarch64/aarch64-sve-builtins-sve2.def
	(svmlalb, svmlalt, svmlalb_lane, svmlalt_lane, svmlallbb, svmlallbt,
	svmlalltb, svmlalltt, svmlalltt_lane, svmlallbb_lane, svmlallbt_lane,
	svmlalltb_lane): Add new DEF_SVE_FUNCTION_GS_FPMs.
	* config/aarch64/aarch64-sve-builtins-sve2.h
	(svmlallbb_lane, svmlallbb, svmlallbt_lane, svmlallbt, svmlalltb_lane,
	svmlalltb, svmlalltt_lane, svmlalltt): Declare.
	* config/aarch64/aarch64-sve-builtins.cc
	(TYPES_h_float_mf8, TYPES_s_float_mf8): Add new types.
	(h_float_mf8, s_float_mf8): Add new SVE_TYPES_ARRAY.
	* config/aarch64/aarch64-sve2.md
	(@aarch64_sve_add_<sve2_fp8_fma_op_vnx8hf><mode>): Add new.
	(@aarch64_sve_add_<sve2_fp8_fma_op_vnx4sf><mode>): Add new.
	(@aarch64_sve_add_lane_<sve2_fp8_fma_op_vnx8hf><mode>): Likewise.
	(@aarch64_sve_add_lane_<sve2_fp8_fma_op_vnx4sf><mode>): Likewise.
	* config/aarch64/aarch64.h
	(TARGET_FP8FMA, TARGET_SSVE_FP8FMA): Likewise.
	* config/aarch64/iterators.md
	(VNx8HF_ONLY): Add new.
	(UNSPEC_FMLALB_FP8, UNSPEC_FMLALLBB_FP8, UNSPEC_FMLALLBT_FP8,
	UNSPEC_FMLALLTB_FP8, UNSPEC_FMLALLTT_FP8, UNSPEC_FMLALT_FP8): Likewise.
	(SVE2_FP8_TERNARY_VNX8HF, SVE2_FP8_TERNARY_VNX4SF): Likewise.
	(SVE2_FP8_TERNARY_LANE_VNX8HF, SVE2_FP8_TERNARY_LANE_VNX4SF): Likewise.
	(sve2_fp8_fma_op_vnx8hf, sve2_fp8_fma_op_vnx4sf): Likewise.
	* doc/invoke.texi: Document fp8fma and sve-fp8fma extensions.

gcc/testsuite/

	* gcc.target/aarch64/sve/acle/asm/test_sve_acle.h
	(TEST_DUAL_Z_REV, TEST_DUAL_LANE_REG, TEST_DUAL_ZD) Add fpm0 argument.
	* gcc.target/aarch64/sve/acle/general-c/ternary_mfloat8_opt_n_1.c: Add
	new shape test.
	* gcc.target/aarch64/sve/acle/general-c/ternary_mfloat8_lane_1.c:
	Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalb_lane_mf8.c: Add new test.
	* gcc.target/aarch64/sve2/acle/asm/mlalb_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlallbb_lane_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlallbb_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlallbt_lane_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlallbt_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalltb_lane_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalltb_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalltt_lane_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalltt_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalt_lane_mf8.c: Likewise.
	* gcc.target/aarch64/sve2/acle/asm/mlalt_mf8.c: Likewise.
	* lib/target-supports.exp: Add check_effective_target for fp8fma and
	ssve-fp8fma