[LLVMdev] major dragonegg improvement

[Duncan Sands]

Hi Andrew,

> Try -mllvm -disable-unroll-scev if you're curious.

unfortunately I never got round to implementing -mllvm for dragonegg.

>
> There can be some luck involved. If you have the bitcode for the important function, I may be able to convert it into a test case to avoid regressing. I usually grab the unoptimized bitcode as follows: -emit-llvm -mllvm -disable-llvm-optzns -o module.bc

For dragonegg that would be:

   -S -flto -fplugin-arg-dragonegg-llvm-ir-optimize=0 -o module.ll

Ciao, Duncan.

>
> -Andy
>
> On Sep 6, 2011, at 12:03 PM, Owen Anderson wrote:
>
>> Seems very likely to be related to Andy's SCEV-unroll-loops changes.
>>
>> --Owen
>>
>> On Sep 6, 2011, at 11:56 AM, Jack Howarth wrote:
>>
>>> I'm not certain yet which commit in the last couple of days caused this,
>>> but the current llvm/dragonegg svn shows a major improvement in the runtime
>>> of the xplor-nih testsuite when xplor-nih is built with FSF gcc 4.6.1 and the
>>> dragonegg plugin at -O3 -ffast-math -funroll-loops. Previously the xplor-nih
>>> testsuite always executed in ~40 sec but now it is coming it at 34.5 sec which
>>> is about the same result seen for xplor-nih built with  native FSF gcc 4.6.1.
>>> It will be interesting to find out if the Polyhedron 2005 benchmarks shows this
>>> behavior as well. Nice.
>>>              Jack
>>> _______________________________________________
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>>
>
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