Re: SPEC2000 comparison of LLVM-3.2 and coming GCC4.8 on x86/x86-64

[Vladimir Makarov <vmakarov at redhat dot com>]

On 02/07/2013 01:51 PM, Duncan Sands wrote:
> Hi Vladimir, thanks for these numbers.
>
> ...
> >    Therefore I had to use *Dragonegg* (a GCC plugin which uses LLVM
> >    backend instead of GCC backend) for generation of Fortran benchmarks
> >    by LLVM.
> ...
> >    I believe such progress is achieved mostly because of a *new RA*
> >    introduced in LLVM 3.0 and *auto-vectorization*.
>
> I don't think it can be auto-vectorization, because I forgot to turn 
> on the
> LLVM auto-vectorizer in dragonegg-3.2 (oops!).
Thanks for pointing this out.  I'll correct this.

I checked it is not switched on for CLANG too.  As I understand this 
stuff is experimental.  I see on my small benchmarks that sometimes it 
generates wrong code and in many cases slower code too.