Re: [Qemu-devel] [PATCH v2 14/29] tcg: Add gvec expanders for variable shift

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> The gvec expanders perform a modulo on the shift count.  If the target
> requires alternate behaviour, then it cannot use the generic gvec
> expanders anyway, and will have to have its own custom code.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  accel/tcg/tcg-runtime.h      |  15 +++
>  tcg/tcg-op-gvec.h            |  11 ++
>  tcg/tcg-op.h                 |   4 +
>  accel/tcg/tcg-runtime-gvec.c | 144 ++++++++++++++++++++++++++
>  tcg/tcg-op-gvec.c            | 195 +++++++++++++++++++++++++++++++++++
>  tcg/tcg-op-vec.c             |  15 +++
>  6 files changed, 384 insertions(+)
>
> diff --git a/accel/tcg/tcg-runtime.h b/accel/tcg/tcg-runtime.h
> index dfe325625c..ed3ce5fd91 100644
> --- a/accel/tcg/tcg-runtime.h
> +++ b/accel/tcg/tcg-runtime.h
> @@ -254,6 +254,21 @@ DEF_HELPER_FLAGS_3(gvec_sar16i, TCG_CALL_NO_RWG, void, ptr, ptr, i32)
>  DEF_HELPER_FLAGS_3(gvec_sar32i, TCG_CALL_NO_RWG, void, ptr, ptr, i32)
>  DEF_HELPER_FLAGS_3(gvec_sar64i, TCG_CALL_NO_RWG, void, ptr, ptr, i32)
>
> +DEF_HELPER_FLAGS_4(gvec_shl8v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shl16v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shl32v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shl64v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +
> +DEF_HELPER_FLAGS_4(gvec_shr8v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shr16v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shr32v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_shr64v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +
> +DEF_HELPER_FLAGS_4(gvec_sar8v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_sar16v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_sar32v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_sar64v, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +
>  DEF_HELPER_FLAGS_4(gvec_eq8, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
>  DEF_HELPER_FLAGS_4(gvec_eq16, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
>  DEF_HELPER_FLAGS_4(gvec_eq32, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> diff --git a/tcg/tcg-op-gvec.h b/tcg/tcg-op-gvec.h
> index ac744ff7c9..84a6247b16 100644
> --- a/tcg/tcg-op-gvec.h
> +++ b/tcg/tcg-op-gvec.h
> @@ -318,6 +318,17 @@ void tcg_gen_gvec_shri(unsigned vece, uint32_t dofs, uint32_t aofs,
>  void tcg_gen_gvec_sari(unsigned vece, uint32_t dofs, uint32_t aofs,
>                         int64_t shift, uint32_t oprsz, uint32_t maxsz);
>
> +/*
> + * Perform vector shift by vector element, modulo the element size.
> + * E.g.  D[i] = A[i] << (B[i] % (8 << vece)).
> + */
> +void tcg_gen_gvec_shlv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz);
> +void tcg_gen_gvec_shrv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz);
> +void tcg_gen_gvec_sarv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz);
> +
>  void tcg_gen_gvec_cmp(TCGCond cond, unsigned vece, uint32_t dofs,
>                        uint32_t aofs, uint32_t bofs,
>                        uint32_t oprsz, uint32_t maxsz);
> diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
> index 9fff9864f6..833c6330b5 100644
> --- a/tcg/tcg-op.h
> +++ b/tcg/tcg-op.h
> @@ -986,6 +986,10 @@ void tcg_gen_shli_vec(unsigned vece, TCGv_vec r, TCGv_vec a, int64_t i);
>  void tcg_gen_shri_vec(unsigned vece, TCGv_vec r, TCGv_vec a, int64_t i);
>  void tcg_gen_sari_vec(unsigned vece, TCGv_vec r, TCGv_vec a, int64_t i);
>
> +void tcg_gen_shlv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec s);
> +void tcg_gen_shrv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec s);
> +void tcg_gen_sarv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec s);
> +
>  void tcg_gen_cmp_vec(TCGCond cond, unsigned vece, TCGv_vec r,
>                       TCGv_vec a, TCGv_vec b);
>
> diff --git a/accel/tcg/tcg-runtime-gvec.c b/accel/tcg/tcg-runtime-gvec.c
> index e2c6f24262..2152fb6903 100644
> --- a/accel/tcg/tcg-runtime-gvec.c
> +++ b/accel/tcg/tcg-runtime-gvec.c
> @@ -725,6 +725,150 @@ void HELPER(gvec_sar64i)(void *d, void *a, uint32_t desc)
>      clear_high(d, oprsz, desc);
>  }
>
> +void HELPER(gvec_shl8v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint8_t)) {
> +        uint8_t sh = *(uint8_t *)(b + i) & 7;
> +        *(uint8_t *)(d + i) = *(uint8_t *)(a + i) << sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shl16v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint16_t)) {
> +        uint8_t sh = *(uint16_t *)(b + i) & 15;
> +        *(uint16_t *)(d + i) = *(uint16_t *)(a + i) << sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shl32v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint32_t)) {
> +        uint8_t sh = *(uint32_t *)(b + i) & 31;
> +        *(uint32_t *)(d + i) = *(uint32_t *)(a + i) << sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shl64v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint64_t)) {
> +        uint8_t sh = *(uint64_t *)(b + i) & 63;
> +        *(uint64_t *)(d + i) = *(uint64_t *)(a + i) << sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shr8v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint8_t)) {
> +        uint8_t sh = *(uint8_t *)(b + i) & 7;
> +        *(uint8_t *)(d + i) = *(uint8_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shr16v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint16_t)) {
> +        uint8_t sh = *(uint16_t *)(b + i) & 15;
> +        *(uint16_t *)(d + i) = *(uint16_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shr32v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint32_t)) {
> +        uint8_t sh = *(uint32_t *)(b + i) & 31;
> +        *(uint32_t *)(d + i) = *(uint32_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_shr64v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(uint64_t)) {
> +        uint8_t sh = *(uint64_t *)(b + i) & 63;
> +        *(uint64_t *)(d + i) = *(uint64_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_sar8v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(vec8)) {
> +        uint8_t sh = *(uint8_t *)(b + i) & 7;
> +        *(int8_t *)(d + i) = *(int8_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_sar16v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(int16_t)) {
> +        uint8_t sh = *(uint16_t *)(b + i) & 15;
> +        *(int16_t *)(d + i) = *(int16_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_sar32v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(vec32)) {
> +        uint8_t sh = *(uint32_t *)(b + i) & 31;
> +        *(int32_t *)(d + i) = *(int32_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
> +void HELPER(gvec_sar64v)(void *d, void *a, void *b, uint32_t desc)
> +{
> +    intptr_t oprsz = simd_oprsz(desc);
> +    intptr_t i;
> +
> +    for (i = 0; i < oprsz; i += sizeof(vec64)) {
> +        uint8_t sh = *(uint64_t *)(b + i) & 63;
> +        *(int64_t *)(d + i) = *(int64_t *)(a + i) >> sh;
> +    }
> +    clear_high(d, oprsz, desc);
> +}
> +
>  /* If vectors are enabled, the compiler fills in -1 for true.
>     Otherwise, we must take care of this by hand.  */
>  #ifdef CONFIG_VECTOR16
> diff --git a/tcg/tcg-op-gvec.c b/tcg/tcg-op-gvec.c
> index 35ebc5a201..061ef329f1 100644
> --- a/tcg/tcg-op-gvec.c
> +++ b/tcg/tcg-op-gvec.c
> @@ -2555,6 +2555,201 @@ void tcg_gen_gvec_sari(unsigned vece, uint32_t dofs, uint32_t aofs,
>      }
>  }
>
> +/*
> + * Expand D = A << (B % element bits)
> + *
> + * Unlike scalar shifts, where it is easy for the target front end
> + * to include the modulo as part of the expansion.  If the target
> + * naturally includes the modulo as part of the operation, great!
> + * If the target has some other behaviour from out-of-range shifts,
> + * then it could not use this function anyway, and would need to
> + * do it's own expansion with custom functions.
> + */
> +static void tcg_gen_shlv_mod_vec(unsigned vece, TCGv_vec d,
> +                                 TCGv_vec a, TCGv_vec b)
> +{
> +    TCGv_vec t = tcg_temp_new_vec_matching(d);
> +
> +    tcg_gen_dupi_vec(vece, t, (8 << vece) - 1);
> +    tcg_gen_and_vec(vece, t, t, b);
> +    tcg_gen_shlv_vec(vece, d, a, t);
> +    tcg_temp_free_vec(t);
> +}
> +
> +static void tcg_gen_shl_mod_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)
> +{
> +    TCGv_i32 t = tcg_temp_new_i32();
> +
> +    tcg_gen_andi_i32(t, b, 31);
> +    tcg_gen_shl_i32(d, a, t);
> +    tcg_temp_free_i32(t);
> +}
> +
> +static void tcg_gen_shl_mod_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
> +{
> +    TCGv_i64 t = tcg_temp_new_i64();
> +
> +    tcg_gen_andi_i64(t, b, 63);
> +    tcg_gen_shl_i64(d, a, t);
> +    tcg_temp_free_i64(t);
> +}
> +
> +void tcg_gen_gvec_shlv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz)
> +{
> +    static const TCGOpcode vecop_list[] = { INDEX_op_shlv_vec, 0 };
> +    static const GVecGen3 g[4] = {
> +        { .fniv = tcg_gen_shlv_mod_vec,
> +          .fno = gen_helper_gvec_shl8v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_8 },
> +        { .fniv = tcg_gen_shlv_mod_vec,
> +          .fno = gen_helper_gvec_shl16v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_16 },
> +        { .fni4 = tcg_gen_shl_mod_i32,
> +          .fniv = tcg_gen_shlv_mod_vec,
> +          .fno = gen_helper_gvec_shl32v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_32 },
> +        { .fni8 = tcg_gen_shl_mod_i64,
> +          .fniv = tcg_gen_shlv_mod_vec,
> +          .fno = gen_helper_gvec_shl64v,
> +          .opt_opc = vecop_list,
> +          .prefer_i64 = TCG_TARGET_REG_BITS == 64,
> +          .vece = MO_64 },
> +    };
> +
> +    tcg_debug_assert(vece <= MO_64);
> +    tcg_gen_gvec_3(dofs, aofs, bofs, oprsz, maxsz, &g[vece]);
> +}
> +
> +/*
> + * Similarly for logical right shifts.
> + */
> +
> +static void tcg_gen_shrv_mod_vec(unsigned vece, TCGv_vec d,
> +                                 TCGv_vec a, TCGv_vec b)
> +{
> +    TCGv_vec t = tcg_temp_new_vec_matching(d);
> +
> +    tcg_gen_dupi_vec(vece, t, (8 << vece) - 1);
> +    tcg_gen_and_vec(vece, t, t, b);
> +    tcg_gen_shrv_vec(vece, d, a, t);
> +    tcg_temp_free_vec(t);
> +}
> +
> +static void tcg_gen_shr_mod_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)
> +{
> +    TCGv_i32 t = tcg_temp_new_i32();
> +
> +    tcg_gen_andi_i32(t, b, 31);
> +    tcg_gen_shr_i32(d, a, t);
> +    tcg_temp_free_i32(t);
> +}
> +
> +static void tcg_gen_shr_mod_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
> +{
> +    TCGv_i64 t = tcg_temp_new_i64();
> +
> +    tcg_gen_andi_i64(t, b, 63);
> +    tcg_gen_shr_i64(d, a, t);
> +    tcg_temp_free_i64(t);
> +}
> +
> +void tcg_gen_gvec_shrv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz)
> +{
> +    static const TCGOpcode vecop_list[] = { INDEX_op_shrv_vec, 0 };
> +    static const GVecGen3 g[4] = {
> +        { .fniv = tcg_gen_shrv_mod_vec,
> +          .fno = gen_helper_gvec_shr8v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_8 },
> +        { .fniv = tcg_gen_shrv_mod_vec,
> +          .fno = gen_helper_gvec_shr16v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_16 },
> +        { .fni4 = tcg_gen_shr_mod_i32,
> +          .fniv = tcg_gen_shrv_mod_vec,
> +          .fno = gen_helper_gvec_shr32v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_32 },
> +        { .fni8 = tcg_gen_shr_mod_i64,
> +          .fniv = tcg_gen_shrv_mod_vec,
> +          .fno = gen_helper_gvec_shr64v,
> +          .opt_opc = vecop_list,
> +          .prefer_i64 = TCG_TARGET_REG_BITS == 64,
> +          .vece = MO_64 },
> +    };
> +
> +    tcg_debug_assert(vece <= MO_64);
> +    tcg_gen_gvec_3(dofs, aofs, bofs, oprsz, maxsz, &g[vece]);
> +}
> +
> +/*
> + * Similarly for arithmetic right shifts.
> + */
> +
> +static void tcg_gen_sarv_mod_vec(unsigned vece, TCGv_vec d,
> +                                 TCGv_vec a, TCGv_vec b)
> +{
> +    TCGv_vec t = tcg_temp_new_vec_matching(d);
> +
> +    tcg_gen_dupi_vec(vece, t, (8 << vece) - 1);
> +    tcg_gen_and_vec(vece, t, t, b);
> +    tcg_gen_sarv_vec(vece, d, a, t);
> +    tcg_temp_free_vec(t);
> +}
> +
> +static void tcg_gen_sar_mod_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)
> +{
> +    TCGv_i32 t = tcg_temp_new_i32();
> +
> +    tcg_gen_andi_i32(t, b, 31);
> +    tcg_gen_sar_i32(d, a, t);
> +    tcg_temp_free_i32(t);
> +}
> +
> +static void tcg_gen_sar_mod_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
> +{
> +    TCGv_i64 t = tcg_temp_new_i64();
> +
> +    tcg_gen_andi_i64(t, b, 63);
> +    tcg_gen_sar_i64(d, a, t);
> +    tcg_temp_free_i64(t);
> +}
> +
> +void tcg_gen_gvec_sarv(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                       uint32_t bofs, uint32_t oprsz, uint32_t maxsz)
> +{
> +    static const TCGOpcode vecop_list[] = { INDEX_op_sarv_vec, 0 };
> +    static const GVecGen3 g[4] = {
> +        { .fniv = tcg_gen_sarv_mod_vec,
> +          .fno = gen_helper_gvec_sar8v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_8 },
> +        { .fniv = tcg_gen_sarv_mod_vec,
> +          .fno = gen_helper_gvec_sar16v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_16 },
> +        { .fni4 = tcg_gen_sar_mod_i32,
> +          .fniv = tcg_gen_sarv_mod_vec,
> +          .fno = gen_helper_gvec_sar32v,
> +          .opt_opc = vecop_list,
> +          .vece = MO_32 },
> +        { .fni8 = tcg_gen_sar_mod_i64,
> +          .fniv = tcg_gen_sarv_mod_vec,
> +          .fno = gen_helper_gvec_sar64v,
> +          .opt_opc = vecop_list,
> +          .prefer_i64 = TCG_TARGET_REG_BITS == 64,
> +          .vece = MO_64 },
> +    };
> +
> +    tcg_debug_assert(vece <= MO_64);
> +    tcg_gen_gvec_3(dofs, aofs, bofs, oprsz, maxsz, &g[vece]);
> +}
> +
>  /* Expand OPSZ bytes worth of three-operand operations using i32 elements.  */
>  static void expand_cmp_i32(uint32_t dofs, uint32_t aofs, uint32_t bofs,
>                             uint32_t oprsz, TCGCond cond)
> diff --git a/tcg/tcg-op-vec.c b/tcg/tcg-op-vec.c
> index 213d2e22aa..96317dbd10 100644
> --- a/tcg/tcg-op-vec.c
> +++ b/tcg/tcg-op-vec.c
> @@ -583,3 +583,18 @@ void tcg_gen_umax_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b)
>  {
>      do_op3(vece, r, a, b, INDEX_op_umax_vec);
>  }
> +
> +void tcg_gen_shlv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b)
> +{
> +    do_op3(vece, r, a, b, INDEX_op_shlv_vec);
> +}
> +
> +void tcg_gen_shrv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b)
> +{
> +    do_op3(vece, r, a, b, INDEX_op_shrv_vec);
> +}
> +
> +void tcg_gen_sarv_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b)
> +{
> +    do_op3(vece, r, a, b, INDEX_op_sarv_vec);
> +}


--
Alex Bennée