#3698: Bad code generated for zip/filter/filter loop
---------------------------------+------------------------------------------
Reporter: rl | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.13
Resolution: | Keywords:
Os: Unknown/Multiple | Testcase:
Architecture: Unknown/Multiple | Failure: Runtime performance bug
---------------------------------+------------------------------------------
Comment (by guest):
Another instance of the irritating arity fixpoint thing. See also #2762,
#2902 and stuff at the top of
http://hackage.haskell.org/trac/ghc/wiki/Status/SLPJ-Tickets
However, even if we had arity fixpoint detection, your function won't get
eta-expanded. Reason: GHC.Classes.< might select an expensive operation
from the dictionary. If this is the case then you might repeat tons of
work. So to eta-expand safely you would need to also detect that go_smr is
only ever used applied with a particular ds_ak5.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3698#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
