[Haskell-cafe] Re: Why can't Haskell be faster?

Don Stewart dons at galois.com
Wed Oct 31 12:01:39 EDT 2007

> Hi
> I've been working on optimising Haskell for a little while
> (http://www-users.cs.york.ac.uk/~ndm/supero/), so here are my thoughts
> on this.  The Clean and Haskell languages both reduce to pretty much
> the same Core language, with pretty much the same type system, once
> you get down to it - so I don't think the difference between the
> performance is a language thing, but it is a compiler thing. The
> uniqueness type stuff may give Clean a slight benefit, but I'm not
> sure how much they use that in their analyses.
> Both Clean and GHC do strictness analysis - I don't know which one
> does better, but both do quite well. I think Clean has some
> generalised fusion framework, while GHC relies on rules and short-cut
> deforestation. GHC goes through C-- to C or ASM, while Clean has been
> generating native code for a lot longer. GHC is based on the STG
> machine, while Clean is based on the ABC machine - not sure which is
> better, but there are differences there.
> My guess is that the native code generator in Clean beats GHC, which
> wouldn't be too surprising as GHC is currently rewriting its CPS and
> Register Allocator to produce better native code.

Yes, this was my analysis too -- its in the native code gen. Which is
perhaps the main GHC bottleneck now.

-- Don

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