Re: [Qemu-devel] [PATCH 19/20] target/arm: Promote consecutive memory ops for aa32

[Philippe Mathieu-Daudé]

On 11/10/2018 22:52, Richard Henderson wrote:
> For a sequence of loads or stores from a single register,
> little-endian operations can be promoted to an 8-byte op.
> This can reduce the number of operations by a factor of 8.
> 
> Signed-off-by: Richard Henderson <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  target/arm/translate.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 12a744b3c3..09f2d648b7 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -5011,6 +5011,16 @@ static int disas_neon_ls_insn(DisasContext *s, 
> uint32_t insn)
>          if (size == 3 && (interleave | spacing) != 1) {
>              return 1;
>          }
> +        /* For our purposes, bytes are always little-endian.  */
> +        if (size == 0) {
> +            endian = MO_LE;
> +        }
> +        /* Consecutive little-endian elements from a single register
> +         * can be promoted to a larger little-endian operation.
> +         */
> +        if (interleave == 1 && endian == MO_LE) {
> +            size = 3;
> +        }
>          tmp64 = tcg_temp_new_i64();
>          addr = tcg_temp_new_i32();
>          tmp2 = tcg_const_i32(1 << size);
>