moving from ghc-6.2 to 6.4

[Keean Schupke]

Thought I would run some benchmarks with different compiler options, so 
I pulled out some code (that compiled fine with 6.2). The code uses 
MArrays to calculate a tree difference between two different XML files. 
Anyway tying to compile with 6.4 I get:

 >ghc-6.3: panic! (the `impossible' happened, GHC version 6.3):
 >        app_match: unbound tpl s{tv a2M9}
 >
 >Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,

Any idea how to track down the cause of this?

    Keean.

Simon Marlow wrote:

>On 29 March 2005 08:59, Johannes Waldmann wrote:
>
>  
>
>>I am trying to bring a larger heap of code
>>(http://141.57.11.163/auto/ ) into 6.4 land (because of wonder
>>stories about faster compilation, faster execution, Data.Map, and so
>>on ...) 
>>Here are a few observations and questions
>>that may be useful to others as well.
>>
>>* what is the situation with ghc-6.4 for sparc/solaris?
>>   I don't see a binary package in the download area.
>>   I started to build from source - can this be successful?
>>
>>   (The rest of this report refers to i386/linux)
>>    
>>
>
>There are some outstanding issues on Sparc/Solaris that I didn't get
>around to investigating before the release.  One of them is a random
>crash, so you should probably consider 6.4 to be broken on Sparc/Solaris
>for the time being (it might be related to gcc version though: 6.2.x
>might be just as broken with recent gcc versions).  I'm keen to get more
>data points, if you have the time & inclination to test it.
>
>We could really do with a Sparc/GHC guru to take up the mantle of
>maintaining the Sparc port - it's kind of hard for us to do it without
>the hardware locally, and I'm no Sparc expert.
>
>  
>
>>* Cabal is very nice! - The only thing that was confusing me
>>   is that I have to list all modules in the *.cabal file:
>>   if I don't, it still happily builds and installs the package
>>   but it cannot be used, giving linker errors. Couldn't this be
>>   checked earlier? Or better, couldn't it infer the needed
>>   hidden modules? Anyway I can generate the module list by a shell
>>   script but that does not feel right. - How do I build and install
>>   a profiling version of a package, how does Cabal support this?
>>    
>>
>
>The module list: yes, I think this is something the Cabal team would
>like to automate in the future.  There's no way to build profiled
>packages at the moment, as far as I'm aware.  I agree it's an important
>feature, though.
> 
>  
>
>>* I don't see "dramatic" improvements in execution times -
>>   are there some magic ghc options I missed? I used -O -fvia-C.
>>   Still, executables are maybe 2 .. 5 % smaller and faster than they
>>   were with 6.2 - and compilation without -O is really fast.
>>    
>>
>
>I don't know where this rumour of dramatic improvements in execution
>time comes from :-)  Our testing shows modest improvements in most
>programs, with some programs going slower.  The focus of 6.4 wasn't
>really on performance, but we hope to merge performance improvements
>back into future 6.4 releases.
>
>Cheers,
>	Simon
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>