[FFmpeg-devel] [PATCH 7/8] lavc/flacenc: add AVX2 version of the 32-bit LPC encoder

[James Darnley]

On 2017-11-27 17:50, Henrik Gramner wrote:
> On Sun, Nov 26, 2017 at 11:51 PM, James Darnley <james.darnley at gmail.com> wrote:
>> -pd_0_int_min: times  2 dd 0, -2147483648
>> -pq_int_min:   times  2 dq -2147483648
>> -pq_int_max:   times  2 dq  2147483647
>> +pd_0_int_min: times  4 dd 0, -2147483648
>> +pq_int_min:   times  4 dq -2147483648
>> +pq_int_max:   times  4 dq  2147483647
> 
> Using 128-bit broadcasts is preferable over duplicating the constants
> to 256-bit unless there's a good reason for doing so since it wastes
> less cache and is faster on AMD CPU:s.

At first I  thought it sounded like a possible candidate for x86-64
optimisation; I have run out of registers on x86.  Although that is in
the inner loop and these constants used in the outer loop or just once
so I have some room.

Do you want to block the patch set while I change this or could it be
left for another time?

Thanks for the suggestion anyway.


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