[gambit-list] Viewing CPS expansion?

D.McClain dbm at asyrmatos.com
Fri May 22 16:13:10 EDT 2009


...thinking back on earlier experiments, I have seen just about the  
same degree of slowdown when converting from applicative style to  
pure functional lazy style (a la Haskell). So that leads me to  
conclude further that it is in the production and subsequent handling  
of closures that costs the speed.

Dr. David McClain
Sr. VP, Embedded Systems
Asyrmatos Inc.
Boston & Tucson
phone: 	520-529-2437
cell: 	520-390-3995
web: 	www.asyrmatos.com
e-mail:	dbm at asyrmatos.com




On May 22, 2009, at 13:04, D.McClain wrote:

> Bingo!
>
> Dr. David McClain
> Sr. VP, Embedded Systems
> Asyrmatos Inc.
> Boston & Tucson
> phone: 	520-529-2437
> cell: 	520-390-3995
> web: 	www.asyrmatos.com
> e-mail:	dbm at asyrmatos.com
>
>
>
>
> On May 22, 2009, at 12:51, Taylor R Campbell wrote:
>
>>    Date: Fri, 22 May 2009 12:45:59 -0700
>>    From: "D.McClain" <dbm at asyrmatos.com>
>>
>>    Okay, you have my attention... let's see that isomorphism in
>>    practice.
>>
>> I leave that as an exercise for the reader.
>>
>>    I have seen my own measurements, and invariably they produce code
>>    that is 30% slower for CPS form than direct form. Perhaps the
>>    compilers producing the actual native code have been tuned to look
>>    for common human idioms and not CPS traits?
>>
>> The way you say that suggests to me that you are using the *same*
>> compiler to compare a direct-style program with the same program
>> converted to continuation-passing style.  Unless the compiler is
>> extremely clever, it will probably generate worse code for the CPS
>> form of the program, for the reason I explained in my first message.
>>
>> That's a very different question, however, from the question of how
>> the use of a CPS intermediate representation affects the code that a
>> compiler generates.
>>
>>
>

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