RISC-V: Support RVV floating-point auto-vectorization

RISC-V: Support RVV floating-point auto-vectorization

This patch adds RVV floating-point auto-vectorization.
Also, fix attribute bug of floating-point ternary operations in vector.md.

gcc/ChangeLog:

	* config/riscv/autovec.md (fma<mode>4): New pattern.
	(*fma<mode>): Ditto.
	(fnma<mode>4): Ditto.
	(*fnma<mode>): Ditto.
	(fms<mode>4): Ditto.
	(*fms<mode>): Ditto.
	(fnms<mode>4): Ditto.
	(*fnms<mode>): Ditto.
	* config/riscv/riscv-protos.h (emit_vlmax_fp_ternary_insn):
	New function.
	* config/riscv/riscv-v.cc (emit_vlmax_fp_ternary_insn): Ditto.
	* config/riscv/vector.md: Fix attribute bug.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/ternop/ternop-1.c: Adjust tests.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-10.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-11.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-12.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-7.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-8.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop-9.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-10.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-11.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-12.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-7.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-8.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run-9.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-1.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-10.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-11.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-12.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-2.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-3.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-4.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-5.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-6.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-7.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-8.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_run_zvfh-9.c: New test.