Re: [PULL 02/10] target/sparc: Use tcg_gen_lookup_and_goto_ptr in gen_goto_tb

[BALATON Zoltan]

On Wed, 28 Jun 2023, Mark Cave-Ayland wrote:
> From: Richard Henderson <richard.henderson@linaro.org>
>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> Message-Id: <20230628071202.230991-2-richard.henderson@linaro.org>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
> target/sparc/translate.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/target/sparc/translate.c b/target/sparc/translate.c
> index bad2ec90a0..28d4cdb8b4 100644
> --- a/target/sparc/translate.c
> +++ b/target/sparc/translate.c
> @@ -318,10 +318,10 @@ static void gen_goto_tb(DisasContext *s, int tb_num,
>         tcg_gen_movi_tl(cpu_npc, npc);
>         tcg_gen_exit_tb(s->base.tb, tb_num);
>     } else {
> -        /* jump to another page: currently not optimized */
> +        /* jump to another page: we can use an indirect jump */
>         tcg_gen_movi_tl(cpu_pc, pc);
>         tcg_gen_movi_tl(cpu_npc, npc);
> -        tcg_gen_exit_tb(NULL, 0);
> +        tcg_gen_lookup_and_goto_ptr();

Out of curiosity, did you test this is actually faster? The reason I ask 
is because I've tried to optimise similar case in target/ppc by using 
lookup_and_goto_ptr but found it was slower than without that. I think 
this may depend on the usage but I wonder if that could be a generic issue 
with lookup_and_goto_ptr or only specific for the case I've tried.

Regards,
BALATON Zoltan

>     }
> }