Unboxed sum performance surprisingly poor
I tried performing worker-wrapper manually on Data.IntMap.lookup
:
lookup# :: Int -> IntMap a -> (# (# #) | a #)
lookup# = -- The obvious modification of the current implementation
lookup :: Int -> IntMap a -> Maybe a
lookup k m = case lookup# k m of
(# | a #) -> Just a
_ -> Nothing
Unfortunately, the lookup
benchmark slowed down. I verified that the benchmark indeed performs an immediate case analysis on the result (with fromMaybe
), so it should go faster. And yet it goes slower.
Caveat: I have not yet gotten things set up to be able to check with 8.4, so if there have been improvements in UnboxedSum
performance since 8.2.2
, this may all be silly.
Trac metadata
Trac field | Value |
---|---|
Version | 8.2.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |