Re: [PATCH 03/46] tcg/optimize: Add fold_masks_zsa, fold_masks_zs, fold_masks_z

[Pierrick Bouvier]

On 12/10/24 07:23, Richard Henderson wrote:
> Add additional routines to pass masks directly, rather than
> storing them into OptContext.  To be used in upcoming patches.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   tcg/optimize.c | 24 ++++++++++++++++++++----
>   1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index 1a9e3258e3..6644d24da6 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -1045,11 +1045,9 @@ static bool fold_const2_commutative(OptContext *ctx, 
> TCGOp *op)
>       return fold_const2(ctx, op);
>   }
>   
> -static bool fold_masks(OptContext *ctx, TCGOp *op)
> +static bool fold_masks_zsa(OptContext *ctx, TCGOp *op, uint64_t z_mask,
> +                           uint64_t s_mask, uint64_t a_mask)
>   {
> -    uint64_t a_mask = ctx->a_mask;
> -    uint64_t z_mask = ctx->z_mask;
> -    uint64_t s_mask = ctx->s_mask;
>       const TCGOpDef *def = &tcg_op_defs[op->opc];
>       TCGTemp *ts;
>   
> @@ -1083,6 +1081,24 @@ static bool fold_masks(OptContext *ctx, TCGOp *op)
>       return true;
>   }
>   
> +__attribute__((unused))
> +static bool fold_masks_zs(OptContext *ctx, TCGOp *op,
> +                          uint64_t z_mask, uint64_t s_mask)
> +{
> +    return fold_masks_zsa(ctx, op, z_mask, s_mask, -1);
> +}
> +
> +__attribute__((unused))
> +static bool fold_masks_z(OptContext *ctx, TCGOp *op, uint64_t z_mask)
> +{
> +    return fold_masks_zsa(ctx, op, z_mask, smask_from_zmask(z_mask), -1);
> +}
> +
> +static bool fold_masks(OptContext *ctx, TCGOp *op)
> +{
> +    return fold_masks_zsa(ctx, op, ctx->z_mask, ctx->s_mask, ctx->a_mask);
> +}
> +
>   /*
>    * Convert @op to NOT, if NOT is supported by the host.
>    * Return true f the conversion is successful, which will still

I see the direction, but why not simply use a structure for this?

If I understand correctly, we'll only pass the masks to callees, so it's 
easy to pass the pointer down (without any heap allocation needed), and 
we can have associated builder functions to create the struct only with 
a limited set of masks, or directly from an existing "ctx".