[FFmpeg-devel] [PATCH] configure: add host libm capability detection

Ganesh Ajjanagadde gajjanag at mit.edu
Thu Nov 26 15:28:45 CET 2015


On Thu, Nov 26, 2015 at 8:50 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
> On Thu, Nov 26, 2015 at 2:10 PM, Ganesh Ajjanagadde <gajjanag at mit.edu> wrote:
>> On Thu, Nov 26, 2015 at 2:49 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>>> On Thu, Nov 26, 2015 at 6:04 AM, Ganesh Ajjanagadde
>>> <gajjanagadde at gmail.com> wrote:
>>>> This is needed in order to obtain what is available for hardcoded
>>>> table generation.
>>>>
>>>> A minimal avutil/host_libm.h is also created.
>>>>
>>>
>>> I'm really not a fan of this change. configure is slow and complex
>>> enough as it is, and host tools don't need to be micro-optimized,
>>> since they are never run by a user.
>>
>> 2 comments:
>> 1. I deliberately kept the host_math_func list very short because I
>> recognized this concern regarding configure's slowness.
>> 2. They are run by a lot of users, since tablegen is done at runtime
>> by default. "Never run by a user" is thus incorrect. It is not a
>> "micro-optimization", pow is often 4x slower than relevant function.
>>
>
> These things are for host code, that is not run by users.

I see what you mean now, alternative solution by Ronald is far
superior. Patch dropped, thanks all.

>
> - Hendrik
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