Re: [Qemu-devel] [PATCH 07/20] tcg-ia64: Use ADDS for small addition

[Aurelien Jarno]

On Thu, Oct 31, 2013 at 01:21:56PM -0700, Richard Henderson wrote:
> Avoids a wasted cycle loading up small constants.
> 
> Simplify the code assuming the tcg optimizer is going to work
> and don't expect the first operand of the add to be constant.
> 
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  tcg/ia64/tcg-target.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/tcg/ia64/tcg-target.c b/tcg/ia64/tcg-target.c
> index b7f74a9..be74606 100644
> --- a/tcg/ia64/tcg-target.c
> +++ b/tcg/ia64/tcg-target.c
> @@ -1067,6 +1067,19 @@ static void tcg_out_alu(TCGContext *s, uint64_t 
> opc_a1, TCGReg ret, TCGArg arg1,
>                     tcg_opc_a1(TCG_REG_P0, opc_a1, ret, arg1, arg2));
>  }
>  
> +static inline void tcg_out_add(TCGContext *s, TCGReg ret, TCGReg arg1,
> +                               TCGArg arg2, int const_arg2)
> +{
> +    if (const_arg2 && arg2 == sextract64(arg2, 0, 14)) {
> +        tcg_out_bundle(s, mmI,
> +                       INSN_NOP_M,
> +                       INSN_NOP_M,
> +                       tcg_opc_a4(TCG_REG_P0, OPC_ADDS_A4, ret, arg2, arg1));
> +    } else {
> +        tcg_out_alu(s, OPC_ADD_A1, ret, arg1, 0, arg2, const_arg2);
> +    }
> +}
> +
>  static inline void tcg_out_eqv(TCGContext *s, TCGArg ret,
>                                 TCGArg arg1, int const_arg1,
>                                 TCGArg arg2, int const_arg2)
> @@ -2068,8 +2081,7 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode 
> opc,
>  
>      case INDEX_op_add_i32:
>      case INDEX_op_add_i64:
> -        tcg_out_alu(s, OPC_ADD_A1, args[0], args[1], const_args[1],
> -                    args[2], const_args[2]);
> +        tcg_out_add(s, args[0], args[1], args[2], const_args[2]);
>          break;
>      case INDEX_op_sub_i32:
>      case INDEX_op_sub_i64:
> @@ -2275,7 +2287,7 @@ static const TCGTargetOpDef ia64_op_defs[] = {
>      { INDEX_op_st16_i32, { "rZ", "r" } },
>      { INDEX_op_st_i32, { "rZ", "r" } },
>  
> -    { INDEX_op_add_i32, { "r", "rI", "rI" } },
> +    { INDEX_op_add_i32, { "r", "rZ", "rI" } },
>      { INDEX_op_sub_i32, { "r", "rI", "rI" } },
>  
>      { INDEX_op_and_i32, { "r", "rI", "rI" } },
> @@ -2322,7 +2334,7 @@ static const TCGTargetOpDef ia64_op_defs[] = {
>      { INDEX_op_st32_i64, { "rZ", "r" } },
>      { INDEX_op_st_i64, { "rZ", "r" } },
>  
> -    { INDEX_op_add_i64, { "r", "rI", "rI" } },
> +    { INDEX_op_add_i64, { "r", "rZ", "rI" } },
>      { INDEX_op_sub_i64, { "r", "rI", "rI" } },
>  
>      { INDEX_op_and_i64, { "r", "rI", "rI" } },

Acked-by: Aurelien Jarno <address@hidden>

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