[PATCH] benchtests: Add sinf traces

[Wilco Dijkstra]

Hi Paul,

>> I looked at the "small" trace. On 1000 inputs, there are lots of duplicates:
>> 232 which are 0, 54 which are 0x1.848f56p-32, 42 which are 0x1.84729p-32,
>> and more than 1/3 which are in [-1e-9,1e9], for which we could simply
>> return x. In my opinion, this is not a good trace, since it would be quite
>> easy to write some code that is very efficient on average for this trace.
>>
>> I will have a look at the other traces next week, unless someone else beats me.

The goal is to be good at real world uses, not on something random. And it
doesn't really matter how many identical or similar values there are, it's
about the distribution of the inputs across the quadrants and special cases.

Note there is little difference between the box2d traces for sinf. And while the
speedup for box2d is 10% higher than the random input, they are not far off,
so the random case shows the same issue.

             sinf       cosf
     random  45.4%      45.2%
      large  68.0%      53.4%
       huge  19.4%      9.8%
box2d-small  58.2%      100.2%
 box2d-hard  56.7%       72.7%
box2d-mixed  52.5%      54.4%

> It is on my backlog, my plan is to use the trace of 3 speccpu2007 benchmarks
> (507.cactuBSSN_r, 526.blender_r, and 544.nab_r) to try create a better one.
> They benchmarks calls the double version, but since the range is within
> -2pi..2pi I think we can extrapolate to float.

The actual binary values matter very little unless they hit cornercases that are
significantly slower. The range is never an issue, nobody ever does sin (DBL_MAX)!

Cheers,
Wilco