Vector data types in fortran

[burlen <burlen@xxxxxxxxxxxxxxxxx>]

Hi,
I have a finite difference code written in fortran, currently I use g77 
to build this code. I would like to know if it is possible to leverage 
gcc vector data types, and SSE instructions etc within the fortran code. 
I notice that when using C it is possible to declare variables as vector 
type. A while back we tried to let the fortran compiler(I think it was 
actually pgf) automagically vectorize but we only got about 10% speed 
up. We should get significantly more if all the potential loops were 
vectorized. I would like to hand tune some of the code. Is it going to 
be possible to vectorize the fortran code using g77/gfortran? Where can 
more information be found?
thanks in advance
Burlen