Re: [Qemu-devel] [PATCH 3/7] tcg: Swap commutative double-word comparisons

[Aurelien Jarno <aurelien@aurel32.net>]

On Thu, Sep 27, 2012 at 10:19:53AM -0700, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/optimize.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index 004c336..d39926e 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -397,6 +397,22 @@ static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
>      return false;
>  }
>  
> +static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
> +{
> +    int sum = 0;
> +    sum += temps[p1[0]].state == TCG_TEMP_CONST;
> +    sum += temps[p1[1]].state == TCG_TEMP_CONST;
> +    sum -= temps[p2[0]].state == TCG_TEMP_CONST;
> +    sum -= temps[p2[1]].state == TCG_TEMP_CONST;
> +    if (sum > 0) {
> +        TCGArg t;
> +        t = p1[0], p1[0] = p2[0], p2[0] = t;
> +        t = p1[1], p1[1] = p2[1], p2[1] = t;
> +        return true;
> +    }
> +    return false;
> +}
> +
>  /* Propagate constants and copies, fold constant expressions. */
>  static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                                      TCGArg *args, TCGOpDef *tcg_op_defs)
> @@ -475,6 +491,16 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>              swap_commutative(args[0], &args[2], &args[4]);
>              swap_commutative(args[1], &args[3], &args[5]);
>              break;
> +        case INDEX_op_brcond2_i32:
> +            if (swap_commutative2(&args[0], &args[2])) {
> +                args[4] = tcg_swap_cond(args[4]);
> +            }
> +            break;
> +        case INDEX_op_setcond2_i32:
> +            if (swap_commutative2(&args[1], &args[3])) {
> +                args[5] = tcg_swap_cond(args[5]);
> +            }
> +            break;
>          default:
>              break;
>          }

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>


-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net