Re: [julia-users] Re: bit-twiddling micro benchmark

[Laszlo Hars]

Stefan, do you know about any plans of LLVM to support rotations and bit 
reversals in the near future? Those are the most important ones missing. I 
tried rot8(x) = x<<8 | x>>>56, and in  my Windows-7 x64 machine it was slow 
(more than twice slower than a shift alone). Bit reversing Int64 takes 
about 40 machine instructions when coded in C or Julia (without huge lookup 
tables), instead of the appropriate single machine instruction in Intel 
CPUs.