[PATCH] ntdll: Optimize memcpy for x86-64.

[Gabriel Ivăncescu]

On 30/03/2022 19:33, Rémi Bernon wrote:
> On 3/30/22 17:27, Jinoh Kang wrote:
>> On 3/23/22 10:33, Elaine Lefler wrote:
>>> Signed-off-by: Elaine Lefler <elaineclefler at gmail.com>
>>> ---
>>>
>>> New vectorized implementation improves performance up to 65%.
>>
>> MSVCRT has one. Maybe deduplicate?
>>
> IIUC upstream isn't very interested in assembly optimized routine, 
> unless really necessary.
> 
> The msvcrt implementation was probably necessary because it's often 
> called by apps, and needs to be as optimal as possible, but I'm not sure 
> ntdll memcpy is used so much. Maybe for realloc though, in which case it 
> might be useful indeed.
> 
> I think an unrolled version like was done for memset should already give 
> good results and should work portably (though I got bitten with memset 
> already, and I wasn't very keen on trying again with memcpy so soon).
> 

Why not just copy pasting it from msvcrt since it's already done?