[LLVMdev] dragonegg svn benchmarks

[Duncan Sands]

Hi Jack,

>       The Polyhedron 2005 benchmark results for dragonegg svn at r141492
> using FSF gcc 4.6.2svn measured on x86_64-apple-darwin11 are listed below.
> The benchmarks used the optimizaton flags...
>
>   -msse4 -ffast-math -funroll-loops -O3
>
> in all cases. The use of -fplugin-arg-dragonegg-enable-gcc-optzns to allow
> for autovectorization from the FSF gcc front-end only produces a single run-time
> regression, fatigue, which is PR10892.

thanks for these numbers.  I suggest you also try -O4.  This does heavier LLVM
optimization when used with -fplugin-arg-dragonegg-enable-gcc-optzns, and seems
to typically result in faster code.  You can also use -O6, which does even more
LLVM optimizing, but seems to slow things down (I didn't analyse why yet).

Ciao, Duncan.

PS: With -fplugin-arg-dragonegg-enable-gcc-optzns the LLVM optimizers are run at
the following levels:

Command line option      LLVM optimizers run at
-------------------      ----------------------
         -O1              tiny amount of optimization
     -O2 or -O3                      -O1
     -O4 or -O5                      -O2
     -O6 or better                   -O3