Re: [PATCH 14/30] tcg/loongarch: Implement bswap32_i32/bswap64_i64

[Richard Henderson]

On 9/20/21 1:04 AM, WANG Xuerui wrote:
> +    case INDEX_op_bswap32_i32:
> +        tcg_out_opc_revb_2h(s, a0, a1);
> +        tcg_out_opc_rotri_w(s, a0, a0, 16);
> +        break;
> +    case INDEX_op_bswap64_i64:
> +        tcg_out_opc_revb_d(s, a0, a1);
> +        break;

You're missing INDEX_op_bswap32_i64, which in addition has a third argument consisting of 
TCG_BSWAP_* bits.

I would have expected revb_2w to be the preferred implementation of bswap32.  I would 
expect something like


    case INDEX_op_bswap32_i32:
        /* All 32-bit values are computed sign-extended in the register. */
        a2 = TCG_BSWAP_OS;
        /* fall through */
    case INDEX_op_bswap32_i64:
        tcg_out_opc_revb_2w(s, a0, a1);
        if (a2 & TCG_BSWAP_OS) {
            tcg_out_ext32s(s, a0, a0);
        } else if (a2 & TCG_BSWAP_OZ) {
            tcg_out_ext32u(s, a0, a0);
        }
        break;


r~