[LLVMdev] pb05 results for current llvm/dragonegg
howarth at bromo.med.uc.edu
Tue Apr 3 08:02:43 CDT 2012
On Tue, Apr 03, 2012 at 10:13:39AM +0200, Duncan Sands wrote:
> Hi Anton,
> >> dragonegg degg+vectorize degg+optnz gfortran
> >> ac 12.45 12.45 8.85 8.80
> >> gas_dyn 11.72 11.80 4.47 4.26
> >> induct 24.02 24.91 12.08 13.65
> >> rnflow 32.25 32.35 26.47 24.06
> > Any idea what might cause such differences here?
> I haven't analysed these, but as a general remark: if "degg+optnz" does much
> better than "dragonegg" then that indicates a weakness in LLVM's IR level
> optimizers, while if "gfortran" does much better than "degg+optnz" then that
> indicates a weakness in LLVM's codegen. Applying this to the above suggests
> that most of the differences are coming from LLVM's IR level optimizers not
> doing a good job somewhere.
I can add a table column benchmarking...
de-gfortran46 -msse3 -ffast-math -funroll-loops -O3 -fno-tree-vectorize -fplugin-arg-dragonegg-enable-gcc-optzns %n.f90 -o %n
which would separate out the vectorization component. This might be more
informative in identifying weak points in the LLVM's IR level.
> Ciao, Duncan.
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