"Woodcrest" Xeon 3.0ghz optimal -march and options???

[Tim Prince]

Conor Robinson wrote:
> Hi,
> 
> I'm running a mac pro with darwin 8.8.1 osx 10.4.8.  3.0ghz Woodcrest
> dual core xeon
> chip with 1.33ghz bus.
> 
> I have gcc 4.0.3 from hpc and 4.1.1 from apple.
> 
> What I would like to know is, what is my -(m)arch and besides -03, how
> can I invoke auto loop vectorization -sse3 etc, or can I since I don't
> see my arch.  I have intels specific gnu friendly compilers, however
> they are not that friendly and would like to stick with gcc.
> 

If you are interested in vectorization, you should find the Intel 
compilers more friendly than the gnu compilers you mention.
  -free-vectorize is the option for gnu auto-vectorization.  It works 
well in gfortran 4.1.1 for simple cases.
For gcc, if you don't want to upgrade to a version with better default 
optimization for Intel, -march=nocona (64-bit) or prescott (32-bit) 
should work well most of the time.  The 64-bit gnu compilers default to 
-mfpmath=sse; specifying that option may help if you use 32-bit compilers.