[Haskell-cafe] Performance Help

[Bryan O'Sullivan]

Dominic Steinitz wrote:

> Any help would be appreciated.

I notice that there's not much user-accessible documentation of what you 
can expect GHC (or some other Haskell implementation) to do and not do 
with a given piece of code.  For example, you have a lot of little 
definitions that clearly traverse the same lists many times.  I've no 
idea where I would look, except for the compiler source, to get a sense 
for when, if ever, the compiler might apply CSE, fusion, or any other 
techniques that come to mind.  So transmitting folk wisdom on what "the 
compiler" might do with any given piece of code counts as another half 
chapter in the "Practical Haskell" book that ought to get written :-)

	<b