Re: [PATCH 10/13] target/i386: optimize CX handling in repeated string operations

[Richard Henderson]

On 12/15/24 03:06, Paolo Bonzini wrote:
> In a repeated string operation, CX/ECX will be decremented until it
> is 0 but never underflow.  Use this observation to avoid a deposit or
> zero-extend operation if the address size of the operation is smaller
> than MO_TL.
>
> As in the previous patch, the patch is structured to include some
> preparatory work for subsequent changes.  In particular, introducing
> cx_next prepares for when ECX will be decremented*before* calling
> fn(s, ot), and therefore cannot yet be written back to cpu_regs.
>
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
>   target/i386/tcg/translate.c | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)

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

r~