F95 vectorization support

[Tobias Burnus]

Tim Prince wrote:
>>  Auto-parallelisation is also
>> available for Fortran by certain compilers, but not for C AFAIK, and I
>> do not know how well this works in gcc.
> Intel C and Fortran support auto-parallelization.  You may argue that 
> it's necessary to write Fortran-like C code to get much benefit from 
> it. Anyway, OpenMP is supported by all major C and Fortran compilers now.

GCC also supports auto-parallelization via -ftree-parallelize-loops=n  
(since 4.3.0), but I don't have any experience with it. I once tried 
auto-parallelization with Intel's ifort, however, after the program 
became ~15% slower (2 threads, dual core AMD), I decided that I will 
ignore auto-parallelization and stick to MPI or OpenMP.

Regarding OpenMP: GCC supports OpenMP 2.5 since 4.2.0 and the current 
experimental version 4.4.0 supports OpenMP 3.0. (As will the next 
version of several other vendors.)

(The task feature of OpenMP 3 is really nice; unfortunately, it will 
take years until one can assume that everyone has a OpenMP-3-capable 
compiler. And thus several projects I've to do with cannot use it any 
time soon. For Fortran 2003 features one has the same problem.)

Tobias