[1/4] target/arm: Vectorize USHL and SSHL

These instructions shift left or right depending on the sign
of the input, and 7 bits are significant to the shift.  This
requires several masks and selects in addition to the actual
shifts to form the complete answer.

That said, the operation is still a small improvement even for
two 64-bit elements -- 13 vector operations instead of 2 * 7
integer operations.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v2: Fix operand ordering for aa32 VSHL.
---
 target/arm/helper.h        |  11 +-
 target/arm/translate.h     |   6 +
 target/arm/neon_helper.c   |  33 ----
 target/arm/translate-a64.c |  18 +--
 target/arm/translate.c     | 301 +++++++++++++++++++++++++++++++++++--
 target/arm/vec_helper.c    |  88 +++++++++++
 6 files changed, 391 insertions(+), 66 deletions(-)

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

> These instructions shift left or right depending on the sign
> of the input, and 7 bits are significant to the shift.  This
> requires several masks and selects in addition to the actual
> shifts to form the complete answer.
>
> That said, the operation is still a small improvement even for
> two 64-bit elements -- 13 vector operations instead of 2 * 7
> integer operations.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> v2: Fix operand ordering for aa32 VSHL.
> ---
>  target/arm/helper.h        |  11 +-
>  target/arm/translate.h     |   6 +
>  target/arm/neon_helper.c   |  33 ----
>  target/arm/translate-a64.c |  18 +--
>  target/arm/translate.c     | 301 +++++++++++++++++++++++++++++++++++--
>  target/arm/vec_helper.c    |  88 +++++++++++
>  6 files changed, 391 insertions(+), 66 deletions(-)
>
> diff --git a/target/arm/helper.h b/target/arm/helper.h
> index 1fb2cb5a77..fc0d594a14 100644
> --- a/target/arm/helper.h
> +++ b/target/arm/helper.h
> @@ -296,14 +296,8 @@ DEF_HELPER_2(neon_abd_s16, i32, i32, i32)
>  DEF_HELPER_2(neon_abd_u32, i32, i32, i32)
>  DEF_HELPER_2(neon_abd_s32, i32, i32, i32)
>
> -DEF_HELPER_2(neon_shl_u8, i32, i32, i32)
> -DEF_HELPER_2(neon_shl_s8, i32, i32, i32)
>  DEF_HELPER_2(neon_shl_u16, i32, i32, i32)
>  DEF_HELPER_2(neon_shl_s16, i32, i32, i32)
> -DEF_HELPER_2(neon_shl_u32, i32, i32, i32)
> -DEF_HELPER_2(neon_shl_s32, i32, i32, i32)
> -DEF_HELPER_2(neon_shl_u64, i64, i64, i64)
> -DEF_HELPER_2(neon_shl_s64, i64, i64, i64)
>  DEF_HELPER_2(neon_rshl_u8, i32, i32, i32)
>  DEF_HELPER_2(neon_rshl_s8, i32, i32, i32)
>  DEF_HELPER_2(neon_rshl_u16, i32, i32, i32)
> @@ -690,6 +684,11 @@ DEF_HELPER_FLAGS_2(frint64_s, TCG_CALL_NO_RWG, f32, f32, ptr)
>  DEF_HELPER_FLAGS_2(frint32_d, TCG_CALL_NO_RWG, f64, f64, ptr)
>  DEF_HELPER_FLAGS_2(frint64_d, TCG_CALL_NO_RWG, f64, f64, ptr)
>
> +DEF_HELPER_FLAGS_4(gvec_sshl_b, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_sshl_h, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_ushl_b, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +DEF_HELPER_FLAGS_4(gvec_ushl_h, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
> +
>  #ifdef TARGET_AARCH64
>  #include "helper-a64.h"
>  #include "helper-sve.h"
> diff --git a/target/arm/translate.h b/target/arm/translate.h
> index dd24f91f26..0c4e6e4bbd 100644
> --- a/target/arm/translate.h
> +++ b/target/arm/translate.h
> @@ -274,6 +274,8 @@ uint64_t vfp_expand_imm(int size, uint8_t imm8);
>  extern const GVecGen3 mla_op[4];
>  extern const GVecGen3 mls_op[4];
>  extern const GVecGen3 cmtst_op[4];
> +extern const GVecGen3 sshl_op[4];
> +extern const GVecGen3 ushl_op[4];
>  extern const GVecGen2i ssra_op[4];
>  extern const GVecGen2i usra_op[4];
>  extern const GVecGen2i sri_op[4];
> @@ -283,6 +285,10 @@ extern const GVecGen4 sqadd_op[4];
>  extern const GVecGen4 uqsub_op[4];
>  extern const GVecGen4 sqsub_op[4];
>  void gen_cmtst_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);
> +void gen_ushl_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b);
> +void gen_sshl_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b);
> +void gen_ushl_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);
> +void gen_sshl_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);
>
>  /*
>   * Forward to the isar_feature_* tests given a DisasContext pointer.
> diff --git a/target/arm/neon_helper.c b/target/arm/neon_helper.c
> index 4259056723..c581ffb7d3 100644
> --- a/target/arm/neon_helper.c
> +++ b/target/arm/neon_helper.c
> @@ -615,24 +615,9 @@ NEON_VOP(abd_u32, neon_u32, 1)
>      } else { \
>          dest = src1 << tmp; \
>      }} while (0)
> -NEON_VOP(shl_u8, neon_u8, 4)
>  NEON_VOP(shl_u16, neon_u16, 2)
> -NEON_VOP(shl_u32, neon_u32, 1)
>  #undef NEON_FN
>
> -uint64_t HELPER(neon_shl_u64)(uint64_t val, uint64_t shiftop)
> -{
> -    int8_t shift = (int8_t)shiftop;
> -    if (shift >= 64 || shift <= -64) {
> -        val = 0;
> -    } else if (shift < 0) {
> -        val >>= -shift;
> -    } else {
> -        val <<= shift;
> -    }
> -    return val;
> -}
> -
>  #define NEON_FN(dest, src1, src2) do { \
>      int8_t tmp; \
>      tmp = (int8_t)src2; \
> @@ -645,27 +630,9 @@ uint64_t HELPER(neon_shl_u64)(uint64_t val, uint64_t shiftop)
>      } else { \
>          dest = src1 << tmp; \
>      }} while (0)
> -NEON_VOP(shl_s8, neon_s8, 4)
>  NEON_VOP(shl_s16, neon_s16, 2)
> -NEON_VOP(shl_s32, neon_s32, 1)
>  #undef NEON_FN
>
> -uint64_t HELPER(neon_shl_s64)(uint64_t valop, uint64_t shiftop)
> -{
> -    int8_t shift = (int8_t)shiftop;
> -    int64_t val = valop;
> -    if (shift >= 64) {
> -        val = 0;
> -    } else if (shift <= -64) {
> -        val >>= 63;
> -    } else if (shift < 0) {
> -        val >>= -shift;
> -    } else {
> -        val <<= shift;
> -    }
> -    return val;
> -}
> -
>  #define NEON_FN(dest, src1, src2) do { \
>      int8_t tmp; \
>      tmp = (int8_t)src2; \
> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> index 2d6cd09634..255a168df6 100644
> --- a/target/arm/translate-a64.c
> +++ b/target/arm/translate-a64.c
> @@ -8685,9 +8685,9 @@ static void handle_3same_64(DisasContext *s, int opcode, bool u,
>          break;
>      case 0x8: /* SSHL, USHL */
>          if (u) {
> -            gen_helper_neon_shl_u64(tcg_rd, tcg_rn, tcg_rm);
> +            gen_ushl_i64(tcg_rd, tcg_rn, tcg_rm);
>          } else {
> -            gen_helper_neon_shl_s64(tcg_rd, tcg_rn, tcg_rm);
> +            gen_sshl_i64(tcg_rd, tcg_rn, tcg_rm);
>          }
>          break;
>      case 0x9: /* SQSHL, UQSHL */
> @@ -11082,6 +11082,10 @@ static void disas_simd_3same_int(DisasContext *s, uint32_t insn)
>                         is_q ? 16 : 8, vec_full_reg_size(s),
>                         (u ? uqsub_op : sqsub_op) + size);
>          return;
> +    case 0x08: /* SSHL, USHL */
> +        gen_gvec_op3(s, is_q, rd, rn, rm,
> +                     u ? &ushl_op[size] : &sshl_op[size]);
> +        return;
>      case 0x0c: /* SMAX, UMAX */
>          if (u) {
>              gen_gvec_fn3(s, is_q, rd, rn, rm, tcg_gen_gvec_umax, size);
> @@ -11197,16 +11201,6 @@ static void disas_simd_3same_int(DisasContext *s, uint32_t insn)
>                  genfn = fns[size][u];
>                  break;
>              }
> -            case 0x8: /* SSHL, USHL */
> -            {
> -                static NeonGenTwoOpFn * const fns[3][2] = {
> -                    { gen_helper_neon_shl_s8, gen_helper_neon_shl_u8 },
> -                    { gen_helper_neon_shl_s16, gen_helper_neon_shl_u16 },
> -                    { gen_helper_neon_shl_s32, gen_helper_neon_shl_u32 },
> -                };
> -                genfn = fns[size][u];
> -                break;
> -            }
>              case 0x9: /* SQSHL, UQSHL */
>              {
>                  static NeonGenTwoOpEnvFn * const fns[3][2] = {
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 698c594e8c..598bb1cc00 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -3580,13 +3580,13 @@ static inline void gen_neon_shift_narrow(int size, TCGv_i32 var, TCGv_i32 shift,
>          if (u) {
>              switch (size) {
>              case 1: gen_helper_neon_shl_u16(var, var, shift); break;
> -            case 2: gen_helper_neon_shl_u32(var, var, shift); break;
> +            case 2: gen_ushl_i32(var, var, shift); break;
>              default: abort();
>              }
>          } else {
>              switch (size) {
>              case 1: gen_helper_neon_shl_s16(var, var, shift); break;
> -            case 2: gen_helper_neon_shl_s32(var, var, shift); break;
> +            case 2: gen_sshl_i32(var, var, shift); break;
>              default: abort();
>              }
>          }
> @@ -4389,6 +4389,282 @@ const GVecGen3 cmtst_op[4] = {
>        .vece = MO_64 },
>  };
>
> +void gen_ushl_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)

nit: this would have been nicer to read if the ops where dst, src, shift
or some such.

> +{
> +    TCGv_i32 lval = tcg_temp_new_i32();
> +    TCGv_i32 rval = tcg_temp_new_i32();
> +    TCGv_i32 lsh = tcg_temp_new_i32();
> +    TCGv_i32 rsh = tcg_temp_new_i32();
> +    TCGv_i32 zero = tcg_const_i32(0);
> +    TCGv_i32 max = tcg_const_i32(32);
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_ext8s_i32(lsh, b);
> +    tcg_gen_neg_i32(rsh, lsh);
> +    tcg_gen_shl_i32(lval, a, lsh);
> +    tcg_gen_shr_i32(rval, a, rsh);
> +    tcg_gen_movcond_i32(TCG_COND_LTU, d, lsh, max, lval, zero);
> +    tcg_gen_movcond_i32(TCG_COND_LTU, d, rsh, max, rval, d);

Do these get dead coded away if the shift is a const?

> +
> +    tcg_temp_free_i32(lval);
> +    tcg_temp_free_i32(rval);
> +    tcg_temp_free_i32(lsh);
> +    tcg_temp_free_i32(rsh);
> +    tcg_temp_free_i32(zero);
> +    tcg_temp_free_i32(max);
> +}
> +
> +void gen_ushl_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
> +{
> +    TCGv_i64 lval = tcg_temp_new_i64();
> +    TCGv_i64 rval = tcg_temp_new_i64();
> +    TCGv_i64 lsh = tcg_temp_new_i64();
> +    TCGv_i64 rsh = tcg_temp_new_i64();
> +    TCGv_i64 zero = tcg_const_i64(0);
> +    TCGv_i64 max = tcg_const_i64(64);
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_ext8s_i64(lsh, b);
> +    tcg_gen_neg_i64(rsh, lsh);
> +    tcg_gen_shl_i64(lval, a, lsh);
> +    tcg_gen_shr_i64(rval, a, rsh);
> +    tcg_gen_movcond_i64(TCG_COND_LTU, d, lsh, max, lval, zero);
> +    tcg_gen_movcond_i64(TCG_COND_LTU, d, rsh, max, rval, d);
> +
> +    tcg_temp_free_i64(lval);
> +    tcg_temp_free_i64(rval);
> +    tcg_temp_free_i64(lsh);
> +    tcg_temp_free_i64(rsh);
> +    tcg_temp_free_i64(zero);
> +    tcg_temp_free_i64(max);
> +}
> +
> +static void gen_ushl_vec(unsigned vece, TCGv_vec d, TCGv_vec a, TCGv_vec b)
> +{
> +    TCGv_vec lval = tcg_temp_new_vec_matching(d);
> +    TCGv_vec rval = tcg_temp_new_vec_matching(d);
> +    TCGv_vec lsh = tcg_temp_new_vec_matching(d);
> +    TCGv_vec rsh = tcg_temp_new_vec_matching(d);
> +    TCGv_vec msk, max;
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_neg_vec(vece, rsh, b);
> +    if (vece == MO_8) {
> +        tcg_gen_mov_vec(lsh, b);
> +    } else {
> +        msk = tcg_temp_new_vec_matching(d);
> +        tcg_gen_dupi_vec(vece, msk, 0xff);
> +        tcg_gen_and_vec(vece, lsh, b, msk);
> +        tcg_gen_and_vec(vece, rsh, rsh, msk);
> +        tcg_temp_free_vec(msk);
> +    }
> +
> +    /*
> +     * Perform possibly out of range shifts, trusting that the operation
> +     * does not trap.  Discard unused results after the fact.
> +     */
> +    tcg_gen_shlv_vec(vece, lval, a, lsh);
> +    tcg_gen_shrv_vec(vece, rval, a, rsh);
> +
> +    max = tcg_temp_new_vec_matching(d);
> +    tcg_gen_dupi_vec(vece, max, 8 << vece);
> +
> +    /*
> +     * The choice of LT (signed) and GEU (unsigned) are biased toward
> +     * the instructions of the x86_64 host.  For MO_8, the whole byte
> +     * is significant so we must use an unsigned compare; otherwise we
> +     * have already masked to a byte and so a signed compare works.
> +     * Other tcg hosts have a full set of comparisons and do not care.
> +     */
> +    if (vece == MO_8) {
> +        tcg_gen_cmp_vec(TCG_COND_GEU, vece, lsh, lsh, max);
> +        tcg_gen_cmp_vec(TCG_COND_GEU, vece, rsh, rsh, max);
> +        tcg_gen_andc_vec(vece, lval, lval, lsh);
> +        tcg_gen_andc_vec(vece, rval, rval, rsh);
> +    } else {
> +        tcg_gen_cmp_vec(TCG_COND_LT, vece, lsh, lsh, max);
> +        tcg_gen_cmp_vec(TCG_COND_LT, vece, rsh, rsh, max);
> +        tcg_gen_and_vec(vece, lval, lval, lsh);
> +        tcg_gen_and_vec(vece, rval, rval, rsh);
> +    }
> +    tcg_gen_or_vec(vece, d, lval, rval);
> +
> +    tcg_temp_free_vec(max);
> +    tcg_temp_free_vec(lval);
> +    tcg_temp_free_vec(rval);
> +    tcg_temp_free_vec(lsh);
> +    tcg_temp_free_vec(rsh);
> +}
> +
> +static const TCGOpcode ushl_list[] = {
> +    INDEX_op_neg_vec, INDEX_op_shlv_vec,
> +    INDEX_op_shrv_vec, INDEX_op_cmp_vec, 0
> +};
> +
> +const GVecGen3 ushl_op[4] = {
> +    { .fniv = gen_ushl_vec,
> +      .fno = gen_helper_gvec_ushl_b,
> +      .opt_opc = ushl_list,
> +      .vece = MO_8 },
> +    { .fniv = gen_ushl_vec,
> +      .fno = gen_helper_gvec_ushl_h,
> +      .opt_opc = ushl_list,
> +      .vece = MO_16 },
> +    { .fni4 = gen_ushl_i32,
> +      .fniv = gen_ushl_vec,
> +      .opt_opc = ushl_list,
> +      .vece = MO_32 },
> +    { .fni8 = gen_ushl_i64,
> +      .fniv = gen_ushl_vec,
> +      .opt_opc = ushl_list,
> +      .vece = MO_64 },
> +};
> +
> +void gen_sshl_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)
> +{
> +    TCGv_i32 lval = tcg_temp_new_i32();
> +    TCGv_i32 rval = tcg_temp_new_i32();
> +    TCGv_i32 lsh = tcg_temp_new_i32();
> +    TCGv_i32 rsh = tcg_temp_new_i32();
> +    TCGv_i32 zero = tcg_const_i32(0);
> +    TCGv_i32 max = tcg_const_i32(31);
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_ext8s_i32(lsh, b);
> +    tcg_gen_neg_i32(rsh, lsh);
> +    tcg_gen_shl_i32(lval, a, lsh);
> +    tcg_gen_umin_i32(rsh, rsh, max);
> +    tcg_gen_sar_i32(rval, a, rsh);
> +    tcg_gen_movcond_i32(TCG_COND_LEU, lval, lsh, max, lval, zero);
> +    tcg_gen_movcond_i32(TCG_COND_LT, d, lsh, zero, rval, lval);
> +
> +    tcg_temp_free_i32(lval);
> +    tcg_temp_free_i32(rval);
> +    tcg_temp_free_i32(lsh);
> +    tcg_temp_free_i32(rsh);
> +    tcg_temp_free_i32(zero);
> +    tcg_temp_free_i32(max);
> +}
> +
> +void gen_sshl_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
> +{
> +    TCGv_i64 lval = tcg_temp_new_i64();
> +    TCGv_i64 rval = tcg_temp_new_i64();
> +    TCGv_i64 lsh = tcg_temp_new_i64();
> +    TCGv_i64 rsh = tcg_temp_new_i64();
> +    TCGv_i64 zero = tcg_const_i64(0);
> +    TCGv_i64 max = tcg_const_i64(63);
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_ext8s_i64(lsh, b);
> +    tcg_gen_neg_i64(rsh, lsh);
> +    tcg_gen_shl_i64(lval, a, lsh);
> +    tcg_gen_umin_i64(rsh, rsh, max);
> +    tcg_gen_sar_i64(rval, a, rsh);
> +    tcg_gen_movcond_i64(TCG_COND_LEU, lval, lsh, max, lval, zero);
> +    tcg_gen_movcond_i64(TCG_COND_LT, d, lsh, zero, rval, lval);
> +
> +    tcg_temp_free_i64(lval);
> +    tcg_temp_free_i64(rval);
> +    tcg_temp_free_i64(lsh);
> +    tcg_temp_free_i64(rsh);
> +    tcg_temp_free_i64(zero);
> +    tcg_temp_free_i64(max);
> +}
> +
> +static void gen_sshl_vec(unsigned vece, TCGv_vec d, TCGv_vec a, TCGv_vec b)
> +{
> +    TCGv_vec lval = tcg_temp_new_vec_matching(d);
> +    TCGv_vec rval = tcg_temp_new_vec_matching(d);
> +    TCGv_vec lsh = tcg_temp_new_vec_matching(d);
> +    TCGv_vec rsh = tcg_temp_new_vec_matching(d);
> +    TCGv_vec tmp = tcg_temp_new_vec_matching(d);
> +
> +    /*
> +     * Rely on the TCG guarantee that out of range shifts produce
> +     * unspecified results, not undefined behaviour (i.e. no trap).
> +     * Discard out-of-range results after the fact.
> +     */
> +    tcg_gen_neg_vec(vece, rsh, b);
> +    if (vece == MO_8) {
> +        tcg_gen_mov_vec(lsh, b);
> +    } else {
> +        tcg_gen_dupi_vec(vece, tmp, 0xff);
> +        tcg_gen_and_vec(vece, lsh, b, tmp);
> +        tcg_gen_and_vec(vece, rsh, rsh, tmp);
> +    }
> +
> +    /* Bound rsh so out of bound right shift gets -1.  */
> +    tcg_gen_dupi_vec(vece, tmp, (8 << vece) - 1);
> +    tcg_gen_umin_vec(vece, rsh, rsh, tmp);
> +    tcg_gen_cmp_vec(TCG_COND_GT, vece, tmp, lsh, tmp);
> +
> +    tcg_gen_shlv_vec(vece, lval, a, lsh);
> +    tcg_gen_sarv_vec(vece, rval, a, rsh);
> +
> +    /* Select in-bound left shift.  */
> +    tcg_gen_andc_vec(vece, lval, lval, tmp);
> +
> +    /* Select between left and right shift.  */
> +    if (vece == MO_8) {
> +        tcg_gen_dupi_vec(vece, tmp, 0);
> +        tcg_gen_cmpsel_vec(TCG_COND_LT, vece, d, lsh, tmp, rval, lval);
> +    } else {
> +        tcg_gen_dupi_vec(vece, tmp, 0x80);
> +        tcg_gen_cmpsel_vec(TCG_COND_LT, vece, d, lsh, tmp, lval, rval);
> +    }
> +
> +    tcg_temp_free_vec(lval);
> +    tcg_temp_free_vec(rval);
> +    tcg_temp_free_vec(lsh);
> +    tcg_temp_free_vec(rsh);
> +    tcg_temp_free_vec(tmp);
> +}
> +
> +static const TCGOpcode sshl_list[] = {
> +    INDEX_op_neg_vec, INDEX_op_umin_vec, INDEX_op_shlv_vec,
> +    INDEX_op_sarv_vec, INDEX_op_cmp_vec, INDEX_op_cmpsel_vec, 0
> +};
> +
> +const GVecGen3 sshl_op[4] = {
> +    { .fniv = gen_sshl_vec,
> +      .fno = gen_helper_gvec_sshl_b,
> +      .opt_opc = sshl_list,
> +      .vece = MO_8 },
> +    { .fniv = gen_sshl_vec,
> +      .fno = gen_helper_gvec_sshl_h,
> +      .opt_opc = sshl_list,
> +      .vece = MO_16 },
> +    { .fni4 = gen_sshl_i32,
> +      .fniv = gen_sshl_vec,
> +      .opt_opc = sshl_list,
> +      .vece = MO_32 },
> +    { .fni8 = gen_sshl_i64,
> +      .fniv = gen_sshl_vec,
> +      .opt_opc = sshl_list,
> +      .vece = MO_64 },
> +};
> +
>  static void gen_uqadd_vec(unsigned vece, TCGv_vec t, TCGv_vec sat,
>                            TCGv_vec a, TCGv_vec b)
>  {
> @@ -4792,6 +5068,12 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
>                                    vec_size, vec_size);
>              }
>              return 0;
> +
> +        case NEON_3R_VSHL:
> +            /* Note the operation is vshl vd,vm,vn */
> +            tcg_gen_gvec_3(rd_ofs, rm_ofs, rn_ofs, vec_size, vec_size,
> +                           u ? &ushl_op[size] : &sshl_op[size]);
> +            return 0;
>          }
>
>          if (size == 3) {
> @@ -4800,13 +5082,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
>                  neon_load_reg64(cpu_V0, rn + pass);
>                  neon_load_reg64(cpu_V1, rm + pass);
>                  switch (op) {
> -                case NEON_3R_VSHL:
> -                    if (u) {
> -                        gen_helper_neon_shl_u64(cpu_V0, cpu_V1, cpu_V0);
> -                    } else {
> -                        gen_helper_neon_shl_s64(cpu_V0, cpu_V1, cpu_V0);
> -                    }
> -                    break;
>                  case NEON_3R_VQSHL:
>                      if (u) {
>                          gen_helper_neon_qshl_u64(cpu_V0, cpu_env,
> @@ -4841,7 +5116,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
>          }
>          pairwise = 0;
>          switch (op) {
> -        case NEON_3R_VSHL:
>          case NEON_3R_VQSHL:
>          case NEON_3R_VRSHL:
>          case NEON_3R_VQRSHL:
> @@ -4921,9 +5195,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
>          case NEON_3R_VHSUB:
>              GEN_NEON_INTEGER_OP(hsub);
>              break;
> -        case NEON_3R_VSHL:
> -            GEN_NEON_INTEGER_OP(shl);
> -            break;
>          case NEON_3R_VQSHL:
>              GEN_NEON_INTEGER_OP_ENV(qshl);
>              break;
> @@ -5332,9 +5603,9 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
>                              }
>                          } else {
>                              if (input_unsigned) {
> -                                gen_helper_neon_shl_u64(cpu_V0, in, tmp64);
> +                                gen_ushl_i64(cpu_V0, in, tmp64);
>                              } else {
> -                                gen_helper_neon_shl_s64(cpu_V0, in, tmp64);
> +                                gen_sshl_i64(cpu_V0, in, tmp64);
>                              }
>                          }
>                          tmp = tcg_temp_new_i32();
> diff --git a/target/arm/vec_helper.c b/target/arm/vec_helper.c
> index dedef62403..fcb3663903 100644
> --- a/target/arm/vec_helper.c
> +++ b/target/arm/vec_helper.c
> @@ -1046,3 +1046,91 @@ void HELPER(gvec_fmlal_idx_a64)(void *vd, void *vn, void *vm,
>      do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status, desc,
>                   get_flush_inputs_to_zero(&env->vfp.fp_status_f16));
>  }
> +
> +void HELPER(gvec_sshl_b)(void *vd, void *vn, void *vm, uint32_t desc)
> +{
> +    intptr_t i, opr_sz = simd_oprsz(desc);
> +    int8_t *d = vd, *n = vn, *m = vm;
> +
> +    for (i = 0; i < opr_sz; ++i) {
> +        int8_t mm = m[i];
> +        int8_t nn = n[i];
> +        int8_t res = 0;
> +        if (mm >= 0) {
> +            if (mm < 8) {
> +                res = nn << mm;
> +            }
> +        } else {
> +            res = nn >> (mm > -8 ? -mm : 7);
> +        }
> +        d[i] = res;
> +    }
> +    clear_tail(d, opr_sz, simd_maxsz(desc));
> +}
> +
> +void HELPER(gvec_sshl_h)(void *vd, void *vn, void *vm, uint32_t desc)
> +{
> +    intptr_t i, opr_sz = simd_oprsz(desc);
> +    int16_t *d = vd, *n = vn, *m = vm;
> +
> +    for (i = 0; i < opr_sz / 2; ++i) {
> +        int8_t mm = m[i];   /* only 8 bits of shift are significant */
> +        int16_t nn = n[i];
> +        int16_t res = 0;
> +        if (mm >= 0) {
> +            if (mm < 16) {
> +                res = nn << mm;
> +            }
> +        } else {
> +            res = nn >> (mm > -16 ? -mm : 15);
> +        }
> +        d[i] = res;
> +    }
> +    clear_tail(d, opr_sz, simd_maxsz(desc));
> +}
> +
> +void HELPER(gvec_ushl_b)(void *vd, void *vn, void *vm, uint32_t desc)
> +{
> +    intptr_t i, opr_sz = simd_oprsz(desc);
> +    uint8_t *d = vd, *n = vn, *m = vm;
> +
> +    for (i = 0; i < opr_sz; ++i) {
> +        int8_t mm = m[i];
> +        uint8_t nn = n[i];
> +        uint8_t res = 0;
> +        if (mm >= 0) {
> +            if (mm < 8) {
> +                res = nn << mm;
> +            }
> +        } else {
> +            if (mm > -8) {
> +                res = nn >> -mm;
> +            }
> +        }
> +        d[i] = res;
> +    }
> +    clear_tail(d, opr_sz, simd_maxsz(desc));
> +}
> +
> +void HELPER(gvec_ushl_h)(void *vd, void *vn, void *vm, uint32_t desc)
> +{
> +    intptr_t i, opr_sz = simd_oprsz(desc);
> +    uint16_t *d = vd, *n = vn, *m = vm;
> +
> +    for (i = 0; i < opr_sz / 2; ++i) {
> +        int8_t mm = m[i];   /* only 8 bits of shift are significant */
> +        uint16_t nn = n[i];
> +        uint16_t res = 0;
> +        if (mm >= 0) {
> +            if (mm < 16) {
> +                res = nn << mm;
> +            }
> +        } else {
> +            if (mm > -16) {
> +                res = nn >> -mm;
> +            }
> +        }
> +        d[i] = res;
> +    }
> +    clear_tail(d, opr_sz, simd_maxsz(desc));
> +}

Anyway otherwise it LGTM:

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

--
Alex Bennée

On 10/17/19 9:01 AM, Alex Bennée wrote:
>> +    /*
>> +     * Rely on the TCG guarantee that out of range shifts produce
>> +     * unspecified results, not undefined behaviour (i.e. no trap).
>> +     * Discard out-of-range results after the fact.
>> +     */
>> +    tcg_gen_ext8s_i32(lsh, b);
>> +    tcg_gen_neg_i32(rsh, lsh);
>> +    tcg_gen_shl_i32(lval, a, lsh);
>> +    tcg_gen_shr_i32(rval, a, rsh);
>> +    tcg_gen_movcond_i32(TCG_COND_LTU, d, lsh, max, lval, zero);
>> +    tcg_gen_movcond_i32(TCG_COND_LTU, d, rsh, max, rval, d);
> 
> Do these get dead coded away if the shift is a const?

They would, although because of the form of the instruction, as a variable
shift from a vector element, I don't expect it to ever be const.  We will have
just read the value from env memory.


r~