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

Ganesh Ajjanagadde gajjanag at mit.edu
Thu Nov 26 14:10:01 CET 2015

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.

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.

> - Hendrik
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