[Haskell-cafe] Re: speed: ghc vs gcc

[Sebastian Sylvan]

No, he asked if comparing the D64 version with the straight gcc one was
"more fair" then comparing a version that precomputes the result with one
that doesn't. That's what I responded to.

On Sat, Feb 21, 2009 at 11:59 PM, Louis Wasserman <wasserman.louis at gmail.com
> wrote:

> Sebastian, that's not Bulat's point.  He's saying that if we make that
> optimization in Haskell, we should at least make the same optimization in
> GCC for fair comparison.  (Though I'm not entirely sure that that
> optimization would be of any use to GCC, but that's a linguistic concern, no
> more.)
>
> His point is valid.  But Don's results *not* obtained by optimizing in this
> fashion are valid comparisons, and the results obtained with this
> optimization are useful for other reasons.
>
> Louis Wasserman
> wasserman.louis at gmail.com
>
>
> On Sat, Feb 21, 2009 at 5:55 PM, Sebastian Sylvan <
> sylvan at student.chalmers.se> wrote:
>
>>
>>
>> On Sat, Feb 21, 2009 at 11:35 PM, Bulat Ziganshin <
>> bulat.ziganshin at 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?
>>>
>>
>> Yes. Clearly so.
>> It still computes the result from scratch - it just uses a trick which
>> generates better code. This is clearly a useful and worthwhile exercise as
>> it shows A) A neat trick with TH, B) A reasonably practical way to produce
>> fast code for the critical parts of a Haskell app, C) a motivating example
>> for implementing a compiler optimization to do it automatically.
>>
>> Just outputting the precomputed result means nothing.
>>
>>
>>
>> --
>> Sebastian Sylvan
>> +44(0)7857-300802
>> UIN: 44640862
>>
>
>


-- 
Sebastian Sylvan
+44(0)7857-300802
UIN: 44640862
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