Re: [Qemu-devel] [PATCH v3 25/26] tcg-aarch64: Prefer unsigned offsets before signed offsets for ldst

[Claudio Fontana <claudio.fontana@huawei.com>]

On 03.04.2014 21:56, Richard Henderson wrote:
> The assembler seems to prefer them, perhaps we should too.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/aarch64/tcg-target.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index a538a87..58597e7 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -645,11 +645,6 @@ static void tcg_out_ldst_r(TCGContext *s, TCGMemOp size, AArch64LdstType type,
>  static void tcg_out_ldst(TCGContext *s, TCGMemOp size, AArch64LdstType type,
>                           TCGReg rd, TCGReg rn, intptr_t offset)
>  {
> -    if (offset >= -256 && offset < 256) {
> -        tcg_out_ldst_9(s, size, type, rd, rn, offset);
> -        return;
> -    }
> -
>      /* If the offset is naturally aligned and in range, then we can
>         use the scaled uimm12 encoding */
>      if (offset >= 0 && !(offset & ((1 << size) - 1))) {
> @@ -660,6 +655,11 @@ static void tcg_out_ldst(TCGContext *s, TCGMemOp size, AArch64LdstType type,
>          }
>      }
>  
> +    if (offset >= -256 && offset < 256) {
> +        tcg_out_ldst_9(s, size, type, rd, rn, offset);
> +        return;
> +    }
> +
>      /* Worst-case scenario, move offset to temp register, use reg offset.  */
>      tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP, offset);
>      tcg_out_ldst_r(s, size, type, rd, rn, TCG_REG_TMP);
> 

Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>