GCC performance with CP2K

[VandeVondele Joost]

I've just tested gcc/gfortran with CP2K, which some of you might know from 
PR29975 and other messages to the list, and observed some very pleasing 
evolution in the runtime of the code. In each case the set of compilation 
options is '-O2 -ffast-math -funroll-loops -ftree-vectorize -march=native' 
(-march=k8-sse3), the intel reference '-O2 -xW -heap-arrays 64'

version      subroutine time[s]

out.intel:          CP2K 504.52

out.gfortran.4.2.3: CP2K 601.35
out.gfortran.4.3.0: CP2K 569.42
out.gfortran.4.4.0: CP2K 508.12

I hope that this rate of improvement sets a standard up to gcc 4.95.3 ;-)

Thanks for your efforts...

Cheers,

Joost