ANNOUNCE: GHC 6.8.3 Release Candidate

Serge D. Mechveliani mechvel at
Mon Jun 2 02:59:45 EDT 2008

On Sun, Jun 01, 2008 at 01:46:43PM -0700, Don Stewart wrote:
> Hello Serge,
> I was looking at the cabal file used to build docon, 
> I note the current flags are:
>    ghc-options:
>       -fglasgow-exts -fallow-overlapping-instances 
>       -fallow-undecidable-instances
>       -fno-warn-overlapping-patterns -fwarn-unused-binds 
>       -fwarn-unused-matches -fwarn-unused-imports
>       -O
>       +RTS -M400m -RTS  
> Do you gain any performance benefit using:
>       -O2 -fvia-C -optc-O2
> I'm wondering.

I tried  -O2 -fvia-C -optc-O2,  
together with making the very test (demotest/Main) under  -O.
In  ghc-6.8.2  this does not gain anything in DoCon in comparison to -O,
it makes things worse:
* the speed of running the test preserves,
* making the DoCon library becomes 4 times slower, 
* the library code becomes 10% larger,
* making the test module becomes ? times slower, 

Concerning the speed of running the test, maybe -O2 does not help because
DoCon uses Integer everywhere instead of Int, I do not know.

I do not apply -O2 in making the test because this takes too much of time
(hours, more than 50 times more than -Onot), and also because this would not 
increase perforamance, because all the time consuming inner loops are in the 
library, not in the test.

> Also, would you be interested in releasing the cabal bundle for docon on
> , so it can be easily installed by others?

Could you explain me, why currently DoCon is not easy to install?
I thought,  install.txt  provides a short instruction which is easy to 
follow. What is difficult there, what could be improved?
What is a cabal bundle? DoCon has the file  docon.cabal. Is not this a
cabal bundle?


Serge Mechveliani
mechvel at

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