RISC-V: Handle differences between XTheadvector and Vector

RISC-V: Handle differences between XTheadvector and Vector

This patch is to handle the differences in instruction generation
between Vector and XTheadVector. In this version, we only support
partial xtheadvector instructions that leverage directly from current
RVV1.0 with simple adding "th." prefix. For different name xtheadvector
instructions but share same patterns as RVV1.0 instructions, we will
use ASM targethook to rewrite the whole string of the instructions in
the following patches.

For some vector patterns that cannot be avoided, we use
"!TARGET_XTHEADVECTOR" to disable them in vector.md in order
not to generate instructions that xtheadvector does not support,
like vmv1r.

gcc/ChangeLog:

	* config.gcc:  Add files for XTheadVector intrinsics.
	* config/riscv/autovec.md: Guard XTheadVector.
	* config/riscv/predicates.md: Disable immediate vl
	for XTheadVector.
	* config/riscv/riscv-c.cc (riscv_pragma_intrinsic):
	Add pragma for XTheadVector.
	* config/riscv/riscv-string.cc (riscv_expand_block_move):
	Guard XTheadVector.
	* config/riscv/riscv-v.cc (vls_mode_valid_p):
	Avoid autovec.
	* config/riscv/riscv-vector-builtins-bases.cc:
	Do not normalize vsetvl instructions for XTheadVector.
	* config/riscv/riscv-vector-builtins-shapes.cc (check_type):
	New check type function.
	(build_one): Adjust for XTheadVector.
	* config/riscv/riscv-vector-switch.def (ENTRY):
	Disable fractional mode for the XTheadVector extension.
	(TUPLE_ENTRY): Likewise.
	* config/riscv/riscv.cc (riscv_v_adjust_bytesize):
	Guard XTheadVector.
	(riscv_preferred_simd_mode): Likewsie.
	(riscv_autovectorize_vector_modes): Likewise.
	(riscv_vector_mode_supported_any_target_p): Likewise.
	(TARGET_VECTOR_MODE_SUPPORTED_ANY_TARGET_P): Likewise.
	* config/riscv/thead.cc (th_asm_output_opcode):
	Rewrite vsetvl instructions.
	* config/riscv/vector.md:
	Include thead-vector.md and change fractional LMUL
	into 1 for vbool.
	* config/riscv/riscv_th_vector.h: New file.
	* config/riscv/thead-vector.md: New file.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pragma-1.c: Add XTheadVector.
	* gcc.target/riscv/rvv/base/abi-1.c: Exclude XTheadVector.
	* lib/target-supports.exp: Add target for XTheadVector.

Co-authored-by: Jin Ma <jinma@linux.alibaba.com>
Co-authored-by: Xianmiao Qu <cooper.qu@linux.alibaba.com>
Co-authored-by: Christoph Müllner <christoph.muellner@vrull.eu>