Re: [PATCH 12/24] tcg/aarch64: Implement negsetcond_*

[Peter Maydell]

On Tue, 8 Aug 2023 at 04:13, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Trivial, as aarch64 has an instruction for this: CSETM.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/aarch64/tcg-target.h     |  4 ++--
>  tcg/aarch64/tcg-target.c.inc | 12 ++++++++++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/tcg/aarch64/tcg-target.h b/tcg/aarch64/tcg-target.h
> index 6080fddf73..e3faa9cff4 100644
> --- a/tcg/aarch64/tcg-target.h
> +++ b/tcg/aarch64/tcg-target.h
> @@ -94,7 +94,7 @@ typedef enum {
>  #define TCG_TARGET_HAS_mulsh_i32        0
>  #define TCG_TARGET_HAS_extrl_i64_i32    0
>  #define TCG_TARGET_HAS_extrh_i64_i32    0
> -#define TCG_TARGET_HAS_negsetcond_i32   0
> +#define TCG_TARGET_HAS_negsetcond_i32   1
>  #define TCG_TARGET_HAS_qemu_st8_i32     0
>
>  #define TCG_TARGET_HAS_div_i64          1
> @@ -130,7 +130,7 @@ typedef enum {
>  #define TCG_TARGET_HAS_muls2_i64        0
>  #define TCG_TARGET_HAS_muluh_i64        1
>  #define TCG_TARGET_HAS_mulsh_i64        1
> -#define TCG_TARGET_HAS_negsetcond_i64   0
> +#define TCG_TARGET_HAS_negsetcond_i64   1
>
>  /*
>   * Without FEAT_LSE2, we must use LDXP+STXP to implement atomic 128-bit load,
> diff --git a/tcg/aarch64/tcg-target.c.inc b/tcg/aarch64/tcg-target.c.inc
> index 35ca80cd56..7d8d114c9e 100644
> --- a/tcg/aarch64/tcg-target.c.inc
> +++ b/tcg/aarch64/tcg-target.c.inc
> @@ -2262,6 +2262,16 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
>                       TCG_REG_XZR, tcg_invert_cond(args[3]));
>          break;
>
> +    case INDEX_op_negsetcond_i32:
> +        a2 = (int32_t)a2;
> +        /* FALLTHRU */

I see this is what we already do for setcond and movcond,
but how does it work when the 2nd input is a register?
Or is reg-reg guaranteed to always use the _i64 op?

> +    case INDEX_op_negsetcond_i64:
> +        tcg_out_cmp(s, ext, a1, a2, c2);
> +        /* Use CSETM alias of CSINV Wd, WZR, WZR, invert(cond).  */
> +        tcg_out_insn(s, 3506, CSINV, ext, a0, TCG_REG_XZR,
> +                     TCG_REG_XZR, tcg_invert_cond(args[3]));
> +        break;
> +
>      case INDEX_op_movcond_i32:
>          a2 = (int32_t)a2;
>          /* FALLTHRU */
> @@ -2868,6 +2878,8 @@ static TCGConstraintSetIndex 
> tcg_target_op_def(TCGOpcode op)
>      case INDEX_op_sub_i64:
>      case INDEX_op_setcond_i32:
>      case INDEX_op_setcond_i64:
> +    case INDEX_op_negsetcond_i32:
> +    case INDEX_op_negsetcond_i64:
>          return C_O1_I2(r, r, rA);
>
>      case INDEX_op_mul_i32:

thanks
-- PMM