[PATCH] Optimized generic expf and exp2f

[Wilco Dijkstra]

Szabolcs Nagy wrote:
> On 05/09/17 21:58, Joseph Myers wrote:
> > On Tue, 5 Sep 2017, Arjan van de Ven wrote:
> 
>>> you mentioned x86 data.. is that based on current git after
>>> the recent optimizations (on a cpu with fma)?
> 
>> Really you need to compare with both the fma and non-fma versions (and 
>> compare the C version built both with and without fma, since one 
>> possibility would be that the C version can replace the x86_64 ones but 
>> should be built twice, with and without fma, to achieve that replacement).

My machine has AVX2 and FMA, and when building the new generic expf
with -mavx2 -mfma I get:

expf reciprocal-throughput: 1.5x faster
expf latency: 1.4x faster

I verified in both cases FMA was used.

Wilco