aarch64: Add support for SME2p1

aarch64: Add support for SME2p1

This patch adds support for FEAT_SME2p1.  There are two sets of
new instructions: MOVAZ to read from ZA and zero the source data,
and new forms of ZERO.  All of them require streaming mode.

MOVAZ can't reuse the existing UNSPEC_SME_READ* patterns because
of the write to ZA.  I did wonder about trying to use a define_subst,
but it seemed a bit too awkward.

gcc/
	* config/aarch64/aarch64-option-extensions.def (sme2p1): New extension.
	* doc/invoke.texi: Document it.
	* config/aarch64/aarch64.h (TARGET_STREAMING_SME2p1): New macro.
	* config/aarch64/aarch64-c.cc (aarch64_update_cpp_builtins):
	Conditionally define __ARM_FEATURE_SME2p1.
	* config/aarch64/iterators.md (UNSPEC_SME_READZ, UNSPEC_SME_READZ_HOR)
	(UNSPEC_SME_READZ_VER): New unspecs.
	(optab, hv): Handle them.
	(SME_READZ_HV): New int iterator.
	* config/aarch64/aarch64-sme.md
	(UNSPEC_SME_ZERO_SLICES): New unspec.
	(@aarch64_sme_<SME_READZ_HV:optab><v_int_container><mode>)
	(*aarch64_sme_<SME_READZ_HV:optab><v_int_container><mode>_plus)
	(@aarch64_sme_<SME_READZ_HV:optab><VNx1TI_ONLY:mode><SVE_FULL:mode>)
	(@aarch64_sme_<SME_READZ_HV:optab><SVE_FULLx24:mode><mode>)
	(*aarch64_sme_<SME_READZ_HV:optab><SVE_FULLx24:mode><mode>_plus)
	(@aarch64_sme_readz<mode>, *aarch64_sme_readz<mode>_plus)
	(@aarch64_sme_zero_za_slices<mode>): New patterns.
	(*aarch64_sme_zero_za_slices<mode>_plus): Likewise.
	* config/aarch64/aarch64-sve-builtins-shapes.h
	(inherent_za_slice): Declare.
	* config/aarch64/aarch64-sve-builtins-shapes.cc
	(inherent_za_slice_def, inherent_za_slice): New shape.
	* config/aarch64/aarch64-sve-builtins-sme.h (svreadz_za)
	(svreadz_hor_za, svreadz_ver_za): Declare.
	* config/aarch64/aarch64-sve-builtins-sme.cc
	(svread_za_slice_base): New class, split out from...
	(svread_za_impl): ...here.
	(svreadz_za_impl, svreadz_za_tile_impl): New type aliases.
	(zero_slices_mode): New function.
	(svzero_za_impl::expand): Handle the slice forms.
	(svreadz_za, svreadz_hor_za, svreadz_ver_za): New functions.
	* config/aarch64/aarch64-sve-builtins-sme.def: Add the SME2p1
	instructions.

gcc/testsuite/
	* lib/target-supports.exp: Test the assembler for sve-b16b16 support.
	* gcc.target/aarch64/pragma_cpp_predefs_4.c: Add tests for
	__ARM_FEATURE_SME2p1.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za128.c: New test.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za16.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za16_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za16_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za32.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za32_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za32_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za64.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za64_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za64_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za8.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za8_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_hor_za8_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za16.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za16_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za16_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za32.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za32_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za32_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za64.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za64_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za64_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za8.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za8_vg2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_ver_za8_vg4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za16_vg1x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za16_vg1x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za32_vg1x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za32_vg1x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za64_vg1x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za64_vg1x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za8_vg1x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/readz_za8_vg1x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg1x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg1x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg2x1.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg2x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg2x4.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg4x1.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg4x2.c: Likewise.
	* gcc.target/aarch64/sme2/acle-asm/zero_za64_vg4x4.c: Likewise.