Re: [PATCH 5/8] target/ppc: Move multiply fixed-point insns (64-bit operands) to decodetree.

[Chinmay Rath <rathc@linux.vnet.ibm.com>]

Hi Richard,

On 4/20/24 21:21, Richard Henderson wrote:
> On 4/19/24 02:25, Chinmay Rath wrote:
>> Hi Richard,
>>
>> On 4/17/24 00:06, Richard Henderson wrote:
>>> On 4/15/24 23:39, Chinmay Rath wrote:
>>>> +static bool trans_MADDHDU(DisasContext *ctx, arg_MADDHDU *a)
>>> ...
>>>> +    tcg_gen_movi_i64(t1, 0);
>>>
>>> Drop the movi.
>>>
>>>> +    tcg_gen_add2_i64(t1, cpu_gpr[a->vrt], lo, hi, cpu_gpr[a->rc], 
>>>> t1);
>>>
>>> Use tcg_constant_i64(0).
>>>
>> Looks like tcg_gen_add2_i64 internally modifies the passed arguments, 
>> hence constant is not expected.
>> However, I tried using tcg_constant_i64(0) as suggested but this 
>> leads to an assert failure :
>> qemu-system-ppc64: ../tcg/tcg.c:5071: tcg_reg_alloc_op: Assertion 
>> `!temp_readonly(ts)' failed.
>
> You misunderstood my suggestion.
>
>   TCGv_i64 t1 = tcg_temp_new_i64();
>   tcg_gen_add2_i64(t1, cpu_gpr[vrt], lo, hi, cpu_gpr[a->rc], 
> tcg_constantant_i64(0));
>
Thank you for the clarification. Will add this to v2.
Regards,
Chinmay
>
> r~
>