Re: chacha20-s390 broken in 8.2.0 in TCG on s390x

[Richard Henderson]

On 1/4/24 01:37, Philippe Mathieu-Daudé wrote:
> Finally changing the constraints on op_rotli_vec seems to fix it:
>
> ---
> diff --git a/tcg/s390x/tcg-target.c.inc b/tcg/s390x/tcg-target.c.inc
> index fbee43d3b0..b3456fe857 100644
> --- a/tcg/s390x/tcg-target.c.inc
> +++ b/tcg/s390x/tcg-target.c.inc
> @@ -3264,13 +3264,13 @@ static TCGConstraintSetIndex 
> tcg_target_op_def(TCGOpcode op)
>       case INDEX_op_ld_vec:
>       case INDEX_op_dupm_vec:
> +    case INDEX_op_rotli_vec:
>           return C_O1_I1(v, r);
>       case INDEX_op_dup_vec:
>           return C_O1_I1(v, vr);
>       case INDEX_op_abs_vec:
>       case INDEX_op_neg_vec:
>       case INDEX_op_not_vec:
> -    case INDEX_op_rotli_vec:
>       case INDEX_op_sari_vec:
>       case INDEX_op_shli_vec:
>       case INDEX_op_shri_vec:
>       case INDEX_op_s390_vuph_vec:
>       case INDEX_op_s390_vupl_vec:
>           return C_O1_I1(v, v);

Definitely not correct, since VERLL requires a vector input to be rotated.

> But I'm outside of my comfort zone so not really sure what I'm doing...
> (I was inspired by the "the instruction verll only allows immediates up
> to 32 bits." comment from
> https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg317099.html)

That message is confused.  The immediate in VERLL is 12 bits (with only 6 bits ever used 
for MO_64).  Dunno where "32 bits" comes from.


r~