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Re: [OT] GCC vs Intel C++ compiler benchmark


Tim Prince <tprinceusa@mindspring.com> writes:

> On Sunday 27 January 2002 04:05, Andreas Jaeger wrote:
>> Claus Fischer <claus.fischer@clausfischer.com> writes:
>> > The rather biased article on http://www.open-mag.com/754088105111.htm
>> > compares Intel's C++ favourably to GCC, without disclosing many
>> > enlightening details.
>> >
>> > I'm not concerned with that but with the notable OS difference
>> > between Linux (SuSE 7.3) and Windows (XP Pro). IMHO a CPU bound
>> > benchmark should see less than 1 % influence from OS and C library.
>> > The graphics shows roughly 7% better performance on Windows for the
>> > same (Intel) compiler.
>>
>> I've done some measurements myself on Linux and the Intel compiler on
>> Linux is really superior.
> I think you mean superior to gcc on certain benchmarks, when the best options 
> are selected.

That's what I meant.

>> > Are there any ABI differences which would justify such a difference?
>>
>> The Intel compiler uses different calling conventions for local
>> functions, can handle whole program optimizations, ...  I don't have a
>> full list of optimizations that the Intel compiler handles better but
>> it would be interesting to know what kind of optimizations really help
>> most for which CPUs.
> The whole program optimizations remain problematical for large projects.
> The peer review system of gcc has performed well in sorting out which 
> optimizations are generally applicable and reliable.

Does anybody have a list of optimizations that are in icc and inferior
or missing in GCC - and would help to improve performance of GCC on
common platforms?

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj


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