RISC-V: Enable COND_LEN_FMA auto-vectorization

Add comments as Robin's suggestion in scatter_store_run-7.c

Enable COND_LEN_FMA auto-vectorization for floating-point FMA auto-vectorization **NO** ffast-math.

Since the middle-end support has been approved and I will merge it after I finished bootstrap && regression on X86.
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624395.html

Now, it's time to send this patch.

Consider this following case:

  __attribute__ ((noipa)) void ternop_##TYPE (TYPE *__restrict dst,            \
					      TYPE *__restrict a,              \
					      TYPE *__restrict b, int n)       \
  {                                                                            \
    for (int i = 0; i < n; i++)                                                \
      dst[i] += a[i] * b[i];                                                   \
  }

TEST_ALL ()

Before this patch:

ternop_double:
        ble     a3,zero,.L5
        mv      a6,a0
.L3:
        vsetvli a5,a3,e64,m1,tu,ma
        slli    a4,a5,3
        vle64.v v1,0(a0)
        vle64.v v2,0(a1)
        vle64.v v3,0(a2)
        sub     a3,a3,a5
        vfmul.vv        v2,v2,v3
        vfadd.vv        v1,v1,v2
        vse64.v v1,0(a6)
        add     a0,a0,a4
        add     a1,a1,a4
        add     a2,a2,a4
        add     a6,a6,a4
        bne     a3,zero,.L3
.L5:
        ret

After this patch:

ternop_double:
	ble	a3,zero,.L5
	mv	a6,a0
.L3:
	vsetvli	a5,a3,e64,m1,tu,ma
	slli	a4,a5,3
	vle64.v	v1,0(a0)
	vle64.v	v2,0(a1)
	vle64.v	v3,0(a2)
	sub	a3,a3,a5
	vfmacc.vv	v1,v3,v2
	vse64.v	v1,0(a6)
	add	a0,a0,a4
	add	a1,a1,a4
	add	a2,a2,a4
	add	a6,a6,a4
	bne	a3,zero,.L3
.L5:
	ret

Notice: This patch only supports COND_LEN_FMA, **NO** COND_LEN_FNMA, ... etc since I didn't support them
        in the middle-end yet.

        Will support them in the following patches soon.

gcc/ChangeLog:

	* config/riscv/autovec.md (cond_len_fma<mode>): New pattern.
	* config/riscv/riscv-protos.h (enum insn_type): New enum.
	(expand_cond_len_ternop): New function.
	* config/riscv/riscv-v.cc (emit_nonvlmax_fp_ternary_tu_insn): Ditto.
	(expand_cond_len_ternop): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/gather-scatter/scatter_store_run-7.c:
	Adapt testcase for link fail.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-1.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-2.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm-3.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm_run-1.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm_run-2.c: New test.
	* gcc.target/riscv/rvv/autovec/ternop/ternop_nofm_run-3.c: New test.

0 files changed, 0 insertions, 0 deletions