I said nothing about fairness, and *never at any point said I thought Don's results were more useful or fair.*  What makes you think that's what I meant to imply?

You have not responded to my separate concern that
> For code that actively requires computation at runtime, I have seen
> no examples of an instance where well-optimized GHC is actually
> dozens or hundreds of times slower than GCC output.

Rather than accusing me of taking sides, if you'd take an actual apples-to-apples comparison, citing the best Haskell results and best GCC results -- without using examples from either language which performed computation at compile-time that would not be possible in everyday programs -- my original claims were true: that GHC code is frequently within 3x the speed of GCC code, and hacked-up GHC code can reach and match GCC performance -- though I agree those hacks require an impractical blowup in code size.  (Depending on your individual interpretation of what an average Haskell program looks like, I concede that 3x might be off by a factor of 2 or so -- but not the factor of 50 you claimed.)

Don's "-D64" results, while *not* a useful gcc-vs-ghc comparison, are relevant if really determined Haskellers are interested in learning how to obtain the absolute optimal perfection from their code.  Don's results *are* useful, but not in the way you say we're claiming.

Louis Wasserman
wasserman.louis@gmail.com


On Sat, Feb 21, 2009 at 5:35 PM, Bulat Ziganshin <bulat.ziganshin@gmail.com> wrote:
Hello Louis,

Sunday, February 22, 2009, 2:30:23 AM, you wrote:

yes, you are right. Don also compared results of 64x-reduced
computation with full one. are you think that these results are more
fair?

> Observation:

> The best gcc result shown in the thread, if I recall, precomputed
> the result of the full computation at compiletime and simply
> outputted it, when we looked at the assembly.

> While I will accept that this could be seen as an optimization GHC
> should have made, I do not accept that this will be the case with
> most everyday code a programmer writes, as most code is not used to
> simply compute arithmetic constants.
>
> For code that actively requires computation at runtime, I have seen
> no examples of an instance where well-optimized GHC is actually
> dozens or hundreds of times slower than GCC output.

> Louis Wasserman
>  wasserman.louis@gmail.com
>