[LLVMdev] The performance of LLVM vs GCC

[Duncan Sands]

Hi Chris,

>>> And this one, with LLVM ~3.0:
>>>
>>> http://www.phoronix.com/scan.php?page=article&item=amd_bulldozer_compilers&num=1
>>
>> What, no dragonegg?! :)
>
> It is worth pointing out that the methodology of Phoronix makes their results basically useless.  They willfully test -O0 codegen against different compilers, don't mention when a test is using OpenMP or not,

yes, I mentioned this in another email in this thread.  I particularly enjoyed
the use of -O0 :)  They know about these issues since they added notes about
-O0 and openmp to one of their previous sets of benchmarks, probably because of
feedback.  They never seemed to realize that smallpt uses openmp though!  I
notice that they do have a note about openmp after the graphicsmagick
benchmark, and don't report results for himeno (they were using -O0 for this
before), so I guess that's progress.

Ciao, Duncan.

  and (in this case) are testing on a micro architecture that only one of the 
compilers is tuned for.
>
> YMMV, but I consider their results to be complete garbage. It's nice to see Clang beating the pants off GCC in some tests though ;-)