tpapp:
Hi,
I have a question about coding and compilers. Suppose that a function is invoked with the same parameters inside another function declaration, eg
-- this example does nothing particularly meaningless g a b c = let something1 = f a b something2 = externalsomething (f a b) 42 something3 = externalsomething2 (137 * (f a b)) in ...
Does it help (performancewise) to have
g a b c = let resultoff = f a b something2 = externalsomething resultoff 42 something3 = externalsomething2 (137 * resultoff) in ...
or does the compiler perform this optimization? More generally, if a function is invoked with the same parameters again (and it doesn't involve anything like monads), does does it makes sense (performancewise) to "store" the result somewhere?
on the wiki, http://www.haskell.org/haskellwiki/Performance/GHC#Common_subexpressions -- Don