#11545: Strictness signature blowup -------------------------------------+------------------------------------- Reporter: jscholl | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): This is because of demand analysis -- the usage part of the demand signature of {{{(/=)}}} isn't reaching to a fixpoint, so it's looping 10 times (because that's the hard-coded upper bound for fixpoint iterations), each time generating a bigger usage type. I'm a bit confused about why this is happening though. First, strictness type is reaching to a fixpoint very fast (maybe in the first iteration), but why? Second, {{{(/=)}}} is actually defined as {{{not (a == b)}}}, and {{{(==)}}} is demand type is top (i.e. (Lazy, Used)). This looks wrong to me, because the definition has case expressions on arguments and recursively calls itself. The strictness part should be more precise than that.. (more on this later...) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11545#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler