Re: [Qemu-devel] [PATCH 14/35] tcg-s390: Rearrange register allocation order.

[Aurelien Jarno <aurelien@aurel32.net>]

On Fri, Jun 04, 2010 at 12:14:22PM -0700, Richard Henderson wrote:
> Try to avoid conflicting with the outgoing function call arguments.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/s390/tcg-target.c |   23 +++++++++++++----------
>  1 files changed, 13 insertions(+), 10 deletions(-)

This patch looks fine.

> diff --git a/tcg/s390/tcg-target.c b/tcg/s390/tcg-target.c
> index 95ea3c8..3944cb1 100644
> --- a/tcg/s390/tcg-target.c
> +++ b/tcg/s390/tcg-target.c
> @@ -149,22 +149,25 @@ static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
>  };
>  #endif
>  
> +/* Since R6 is a potential argument register, choose it last of the
> +   call-saved registers.  Likewise prefer the call-clobbered registers
> +   in reverse order to maximize the chance of avoiding the arguments.  */
>  static const int tcg_target_reg_alloc_order[] = {
> -    TCG_REG_R6,
> -    TCG_REG_R7,
> -    TCG_REG_R8,
> -    TCG_REG_R9,
> -    TCG_REG_R10,
> -    TCG_REG_R11,
> -    TCG_REG_R12,
>      TCG_REG_R13,
> +    TCG_REG_R12,
> +    TCG_REG_R11,
> +    TCG_REG_R10,
> +    TCG_REG_R9,
> +    TCG_REG_R8,
> +    TCG_REG_R7,
> +    TCG_REG_R6,
>      TCG_REG_R14,
>      TCG_REG_R0,
>      TCG_REG_R1,
> -    TCG_REG_R2,
> -    TCG_REG_R3,
> -    TCG_REG_R4,
>      TCG_REG_R5,
> +    TCG_REG_R4,
> +    TCG_REG_R3,
> +    TCG_REG_R2,
>  };
>  
>  static const int tcg_target_call_iarg_regs[] = {
> -- 
> 1.7.0.1
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net