diff mbox series

[v3,06/14] tcg/riscv: Implement vector mov/dup{m/i}

Message ID 20240904142739.854-7-zhiwei_liu@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series Add support for vector | expand

Commit Message

LIU Zhiwei Sept. 4, 2024, 2:27 p.m. UTC 
From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>

Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/riscv/tcg-target.c.inc | 53 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

Comments

Richard Henderson Sept. 5, 2024, 6:56 a.m. UTC | #1 
On 9/4/24 07:27, LIU Zhiwei wrote:
> @@ -698,6 +704,21 @@ static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
>       case TCG_TYPE_I64:
>           tcg_out_opc_imm(s, OPC_ADDI, ret, arg, 0);
>           break;
> +    case TCG_TYPE_V64:
> +    case TCG_TYPE_V128:
> +    case TCG_TYPE_V256:
> +        {
> +            int nf = get_vec_type_bytes(type) / riscv_vlenb;
> +
> +            if (nf != 0) {
> +                tcg_debug_assert(is_power_of_2(nf) && nf <= 8);
> +                tcg_out_opc_vi(s, OPC_VMVNR_V, ret, arg, nf - 1, true);
> +            } else {
> +                riscv_set_vec_config_vl(s, type);
> +                tcg_out_opc_vv(s, OPC_VMV_V_V, ret, TCG_REG_V0, arg, true);
> +            }
> +        }
> +        break;

Perhaps

         int lmul = type - riscv_lg2_vlenb;
         int nf = 1 << MIN(lmul, 0);
         tcg_out_opc_vi(s, OPC_VMVNR_V, ret, arg, nf - 1);

Is there a reason to prefer vmv.v.v over vmvnr.v?
Seems like we can always move one vector reg...

> +static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
> +                                    TCGReg dst, int64_t arg)
> +{
> +    if (arg < 16 && arg >= -16) {
> +        riscv_set_vec_config_vl_vece(s, type, vece);
> +        tcg_out_opc_vi(s, OPC_VMV_V_I, dst, TCG_REG_V0, arg, true);
> +        return;
> +    }
> +    tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP0, arg);
> +    tcg_out_dup_vec(s, type, vece, dst, TCG_REG_TMP0);
> +}

I'll note that 0 and -1 do not require SEW change. I don't know how often that will come 
up, since in my testing with aarch64, we usually needed to swap to TCG_TYPE_V256 anyway.


r~
LIU Zhiwei Sept. 10, 2024, 1:13 a.m. UTC | #2 
On 2024/9/5 14:56, Richard Henderson wrote:
> On 9/4/24 07:27, LIU Zhiwei wrote:
>> @@ -698,6 +704,21 @@ static bool tcg_out_mov(TCGContext *s, TCGType 
>> type, TCGReg ret, TCGReg arg)
>>       case TCG_TYPE_I64:
>>           tcg_out_opc_imm(s, OPC_ADDI, ret, arg, 0);
>>           break;
>> +    case TCG_TYPE_V64:
>> +    case TCG_TYPE_V128:
>> +    case TCG_TYPE_V256:
>> +        {
>> +            int nf = get_vec_type_bytes(type) / riscv_vlenb;
>> +
>> +            if (nf != 0) {
>> +                tcg_debug_assert(is_power_of_2(nf) && nf <= 8);
>> +                tcg_out_opc_vi(s, OPC_VMVNR_V, ret, arg, nf - 1, true);
>> +            } else {
>> +                riscv_set_vec_config_vl(s, type);
>> +                tcg_out_opc_vv(s, OPC_VMV_V_V, ret, TCG_REG_V0, arg, 
>> true);
>> +            }
>> +        }
>> +        break;
>
> Perhaps
>
>         int lmul = type - riscv_lg2_vlenb;
>         int nf = 1 << MIN(lmul, 0);
>         tcg_out_opc_vi(s, OPC_VMVNR_V, ret, arg, nf - 1);
>
> Is there a reason to prefer vmv.v.v over vmvnr.v?

I think it's a trade-off. For some CPUs,  instruction will be split 
internally. Thus the less the fraction lmul is, the less micro ops for 
execution.
That's the benefit of using vmv.v.v. But here we also need a vsetivli. 
On some cpus, it can be fusion-ed to the next instruction.

> Seems like we can always move one vector reg...
OK. I will take this way.
>
>> +static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned 
>> vece,
>> +                                    TCGReg dst, int64_t arg)
>> +{
>> +    if (arg < 16 && arg >= -16) {
>> +        riscv_set_vec_config_vl_vece(s, type, vece);
>> +        tcg_out_opc_vi(s, OPC_VMV_V_I, dst, TCG_REG_V0, arg, true);
>> +        return;
>> +    }
>> +    tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP0, arg);
>> +    tcg_out_dup_vec(s, type, vece, dst, TCG_REG_TMP0);
>> +}
>
> I'll note that 0 and -1 do not require SEW change. I don't know how 
> often that will come up

On our test on OpenCV, we get a rate of 99.7%. Thus we will optimize 
this next version.

Thanks,
Zhiwei

> , since in my testing with aarch64, we usually needed to swap to 
> TCG_TYPE_V256 anyway.
>
>
> r~
diff mbox series

Patch

diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 4b1079fc6f..ddb0c8190c 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -309,6 +309,12 @@  typedef enum {
     OPC_VS2R_V = 0x2000027 | V_UNIT_STRIDE_WHOLE_REG | V_NF(1),
     OPC_VS4R_V = 0x2000027 | V_UNIT_STRIDE_WHOLE_REG | V_NF(3),
     OPC_VS8R_V = 0x2000027 | V_UNIT_STRIDE_WHOLE_REG | V_NF(7),
+
+    OPC_VMV_V_V = 0x5e000057 | V_OPIVV,
+    OPC_VMV_V_I = 0x5e000057 | V_OPIVI,
+    OPC_VMV_V_X = 0x5e000057 | V_OPIVX,
+
+    OPC_VMVNR_V = 0x9e000057 | V_OPIVI,
 } RISCVInsn;
 
 /*
@@ -698,6 +704,21 @@  static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
     case TCG_TYPE_I64:
         tcg_out_opc_imm(s, OPC_ADDI, ret, arg, 0);
         break;
+    case TCG_TYPE_V64:
+    case TCG_TYPE_V128:
+    case TCG_TYPE_V256:
+        {
+            int nf = get_vec_type_bytes(type) / riscv_vlenb;
+
+            if (nf != 0) {
+                tcg_debug_assert(is_power_of_2(nf) && nf <= 8);
+                tcg_out_opc_vi(s, OPC_VMVNR_V, ret, arg, nf - 1, true);
+            } else {
+                riscv_set_vec_config_vl(s, type);
+                tcg_out_opc_vv(s, OPC_VMV_V_V, ret, TCG_REG_V0, arg, true);
+            }
+        }
+        break;
     default:
         g_assert_not_reached();
     }
@@ -1106,6 +1127,33 @@  static void tcg_out_addsub2(TCGContext *s,
     }
 }
 
+static bool tcg_out_dup_vec(TCGContext *s, TCGType type, unsigned vece,
+                                   TCGReg dst, TCGReg src)
+{
+    riscv_set_vec_config_vl_vece(s, type, vece);
+    tcg_out_opc_vx(s, OPC_VMV_V_X, dst, TCG_REG_V0, src, true);
+    return true;
+}
+
+static bool tcg_out_dupm_vec(TCGContext *s, TCGType type, unsigned vece,
+                                    TCGReg dst, TCGReg base, intptr_t offset)
+{
+    tcg_out_ld(s, TCG_TYPE_REG, TCG_REG_TMP0, base, offset);
+    return tcg_out_dup_vec(s, type, vece, dst, TCG_REG_TMP0);
+}
+
+static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
+                                    TCGReg dst, int64_t arg)
+{
+    if (arg < 16 && arg >= -16) {
+        riscv_set_vec_config_vl_vece(s, type, vece);
+        tcg_out_opc_vi(s, OPC_VMV_V_I, dst, TCG_REG_V0, arg, true);
+        return;
+    }
+    tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP0, arg);
+    tcg_out_dup_vec(s, type, vece, dst, TCG_REG_TMP0);
+}
+
 static const struct {
     RISCVInsn op;
     bool swap;
@@ -2234,6 +2282,9 @@  static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
     a2 = args[2];
 
     switch (opc) {
+    case INDEX_op_dupm_vec:
+        tcg_out_dupm_vec(s, type, vece, a0, a1, a2);
+        break;
     case INDEX_op_ld_vec:
         tcg_out_ld(s, type, a0, a1, a2);
         break;
@@ -2405,6 +2456,8 @@  static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
 
     case INDEX_op_st_vec:
         return C_O0_I2(v, r);
+    case INDEX_op_dup_vec:
+    case INDEX_op_dupm_vec:
     case INDEX_op_ld_vec:
         return C_O1_I1(v, r);
     default: