Gnuradio uses volk which has vectorised pow() for 32
   bits: [1]https://github.com/gnuradio/volk/blob/master/kernels/volk/volk
   _32f_s32f_power_32f.h
   Might be slower due to precision, unknown.
   It would make sense to contribute a 64 bit vectorised pow() to volk but
   doing so is not required.  If adding my previous contribution, mention
   it having taken so long with a link to the issue thread.  If you can,
   mention political targeting and abuse regarding pursuing public
   shielding or somesuch.

References

   1. https://github.com/gnuradio/volk/blob/master/kernels/volk/volk_32f_s32f_power_32f.h