Re: [PATCH 1/2] target/s390x: Use mutable temporary value for op_ts

[Richard Henderson]

On 3/18/24 06:26, Ilya Leoshkevich wrote:
> From: Ido Plat <ido.plat@ibm.com>
>
> Otherwise TCG would assume the register that holds t1 would be constant
> and reuse whenever it needs the value within it.
>
> Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
> [iii: Adjust a newline and capitalization]
> Signed-off-by: Ido Plat <ido.plat@ibm.com>
> ---
>   target/s390x/tcg/translate.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c
> index 0d0c672c959..3fdddac7684 100644
> --- a/target/s390x/tcg/translate.c
> +++ b/target/s390x/tcg/translate.c
> @@ -4781,8 +4781,9 @@ static DisasJumpType op_trXX(DisasContext *s, DisasOps *o)
>   
>   static DisasJumpType op_ts(DisasContext *s, DisasOps *o)
>   {
> -    TCGv_i32 t1 = tcg_constant_i32(0xff);
> +    TCGv_i32 t1 = tcg_temp_new_i32();
>   
> +    tcg_gen_movi_i32(t1, 0xff);
>       tcg_gen_atomic_xchg_i32(t1, o->in2, t1, get_mem_index(s), MO_UB);

Better as

    TCGv_i32 ff = tcg_constant_i32(0xff);
    TCGv_i32 t1 = tcg_temp_new_i32();

    tcg_gen_atomic_xchg_i32(t1, o->in2, ff, get_mem_index(s), MO_UB);

With that,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~