aarch64: add 8-bit floating point dot product

aarch64: add 8-bit floating point dot product

This patch adds support for the following intrinsics when sme-f8f16 is enabled:
  * svdot_za16[_mf8]_vg1x2_fpm
  * svdot_za16[_mf8]_vg1x4_fpm
  * svdot[_single]_za16[_mf8]_vg1x2_fpm
  * svdot[_single]_za16[_mf8]_vg1x4_fpm
  * svdot_lane_za16[_mf8]_vg1x2_fpm
  * svdot_lane_za16[_mf8]_vg1x4_fpm

This patch adds support for the following intrinsics when sme-f8f32 is enabled:
  * svdot_za32[_mf8]_vg1x2_fpm
  * svdot_za32[_mf8]_vg1x4_fpm
  * svdot[_single]_za32[_mf8]_vg1x2_fpm
  * svdot[_single]_za32[_mf8]_vg1x4_fpm
  * svdot_lane_za32[_mf8]_vg1x2_fpm
  * svdot_lane_za32[_mf8]_vg1x4_fpm
  * svvdot_lane_za32[_mf8]_vg1x2_fpm
  * svvdotb_lane_za32[_mf8]_vg1x4_fpm
  * svvdott_lane_za32[_mf8]_vg1x4_fpm

gcc:

	* config/aarch64/aarch64-sme.md
	(@aarch64_sme_<optab><SME_ZA_F8F16_32:mode><SME_ZA_FP8_x24:mode>): New insn.
	(@aarch64_fvdot_half<optab>): Likewise.
	(@aarch64_fvdot_half<optab>_plus): Likewise.
	* config/aarch64/aarch64-sve-builtins-functions.h
	(class svvdot_half_impl): New function impl.
	* config/aarch64/aarch64-sve-builtins-sme.cc (FUNCTION): Likewise.
	* config/aarch64/aarch64-sve-builtins-shapes.cc (struct dot_half_za_slice_lane_def):
	New function shape.
	* config/aarch64/aarch64-sve-builtins-shapes.h: Likewise.
	* config/aarch64/aarch64-sve-builtins-sme.def (svdot): New function.
	(svdot_lane): Likewise.
	(svvdot_lane): Likewise.
	(svvdotb_lane): Likewise.
	(svvdott_lane): Likewise.
	* config/aarch64/aarch64-sve-builtins-sme.h (svvdotb_lane_za): New function.
	(svvdott_lane_za): Likewise.
	* config/aarch64/aarch64-sve-builtins.cc (TYPES_za_s_mf8): New types array.
	(TYPES_za_hs_mf8): Likewise.
	(za_hs_mf8): Likewise.
	* config/aarch64/iterators.md (SME_ZA_F8F16): New mode iterator.
	(SME_ZA_F8F32): Likewise.
	(SME_ZA_FP8_x1): Likewise.
	(SME_ZA_FP8_x2): Likewise.
	(SME_ZA_FP8_x4): Likewise.
	(UNSPEC_SME_FDOT_FP8): New unspec.
	(UNSPEC_SME_FVDOT_FP8): Likewise.
	(UNSPEC_SME_FVDOTT_FP8): Likewise.
	(UNSPEC_SME_FVDOTB_FP8): Likewise.
	(SME_FP8_DOTPROD): New int iterator.
	(SME_FP8_FVDOT): Likewise.
	(SME_FP8_FVDOT_HALF): Likewise.

gcc/testsuite:

	* gcc.target/aarch64/sme2/acle-asm/dot_lane_za16_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_lane_za16_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_lane_za32_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_lane_za32_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_single_za16_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_single_za16_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_single_za32_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_single_za32_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_za16_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_za16_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_za32_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/dot_za32_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/vdot_lane_za16_mf8_vg1x2.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/vdotb_lane_za32_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/vdott_lane_za32_mf8_vg1x4.c: New test.
	* gcc.target/aarch64/sve/acle/general-c/dot_half_za_slice_lane_fpm.c: New test.