Re: [Qemu-devel] [PATCH 2/2] tcg/arm: Implement movcond_i32

[Paolo Bonzini <pbonzini@redhat.com>]

Il 26/09/2012 20:48, Peter Maydell ha scritto:
> Implement movcond_i32 for ARM, as the sequence
>   mov dst, v2   (implicitly done by the tcg common code)
>   cmp c1, c2
>   movCC dst, v1

Should you make tcg/optimize.c prefer "movcond a, a, b" to "movcond a,
b, a", similar to commit c2b0e2f (tcg/optimize: prefer the "op a, a, b"
form for commutative ops, 2012-09-19)?

Paolo

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  tcg/arm/tcg-target.c |   10 ++++++++++
>  tcg/arm/tcg-target.h |    2 +-
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
> index a83b295..e38fd65 100644
> --- a/tcg/arm/tcg-target.c
> +++ b/tcg/arm/tcg-target.c
> @@ -1587,6 +1587,15 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
>      case INDEX_op_movi_i32:
>          tcg_out_movi32(s, COND_AL, args[0], args[1]);
>          break;
> +    case INDEX_op_movcond_i32:
> +        /* Constraints mean that v2 is always in the same register as dest,
> +         * so we only need to do "if condition passed, move v1 to dest".
> +         */
> +        tcg_out_dat_rI(s, COND_AL, ARITH_CMP, 0,
> +                       args[1], args[2], const_args[2]);
> +        tcg_out_dat_rI(s, tcg_cond_to_arm_cond[args[5]],
> +                       ARITH_MOV, args[0], 0, args[3], const_args[3]);
> +        break;
>      case INDEX_op_add_i32:
>          c = ARITH_ADD;
>          goto gen_arith;
> @@ -1798,6 +1807,7 @@ static const TCGTargetOpDef arm_op_defs[] = {
>  
>      { INDEX_op_brcond_i32, { "r", "rI" } },
>      { INDEX_op_setcond_i32, { "r", "r", "rI" } },
> +    { INDEX_op_movcond_i32, { "r", "r", "rI", "rI", "0" } },
>  
>      /* TODO: "r", "r", "r", "r", "ri", "ri" */
>      { INDEX_op_add2_i32, { "r", "r", "r", "r", "r", "r" } },
> diff --git a/tcg/arm/tcg-target.h b/tcg/arm/tcg-target.h
> index e2299ca..0df3352 100644
> --- a/tcg/arm/tcg-target.h
> +++ b/tcg/arm/tcg-target.h
> @@ -73,7 +73,7 @@ typedef enum {
>  #define TCG_TARGET_HAS_nand_i32         0
>  #define TCG_TARGET_HAS_nor_i32          0
>  #define TCG_TARGET_HAS_deposit_i32      0
> -#define TCG_TARGET_HAS_movcond_i32      0
> +#define TCG_TARGET_HAS_movcond_i32      1
>  
>  #define TCG_TARGET_HAS_GUEST_BASE
>  
>