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Re: GCC-4.5.0 comparison with previous releases and LLVM-2.7 on SPEC2000 for x86/x86_64


On Sat, May 1, 2010 at 2:36 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>>
>> Vortex needs -fno-strict-aliasing. ?It casts between two record types
>> with one record being a 'prefix' of another.
>
> So today runs are complette. ?Thanks to Richi who fixed ICE in symtab merging
> that affected perl and GCC. ?With vortex problem was that in addition to
> -fno-strict-aliasing it is writting to closed files that cause ICE depending on
> partiuclar glibc version.
>
> Comparing http://gcc.opensuse.org/SPEC/CINT/sb-frescobaldi.suse.de-fdo-64-FDO/recent.html
> vortex is 2036 with -O2 -flto, 2438 with -O2 -flto and FDO (so about 20% improvement)
> http://gcc.opensuse.org/SPEC/CINT/sb-frescobaldi.suse.de-head-64/list.html
> has -O2 runs without LTO that is 1859, so 31% for LTO+FDO, 10% LTO.
>
> Any idea if it is one of value transforms or just edge profile making the
> difference? ?There are some cases of write only globals we can constant
> propagate with -fwhole-program in SPEC, but I think it is parser.
>

I got the following number for O2, FDO, and LIPO : 2351, 2761 (17%), 3448 (24%).

The FDO improvement over O2 come from both edge profile and vpt
(div,rem). With FDO, one of the important loops in Part_Delete may get
tail duplicated which helps performance.

LIPO improvement mainly come from cross module ininling of hot
functions Mem_GetWord, Mem_GetAddr, Chunk_ChkGetChunk.

David


> Honza
>>
>> David
>>
>>
>>
>> > Honza
>> >
>


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