#14844: SpecConstr also non-recursive function -------------------------------------+------------------------------------- Reporter: nomeata | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Resolution: | Keywords: SpecConstr Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): I distilled this example to show the effect {{{ module T14844Example (bar1, bar2) where large x = x {-# NOINLINE large #-} foo :: Int -> (a -> b -> Bool) -> (a,b) -> Bool foo 0 _ _ = False foo s f t = l s' t where l 0 t = False l 1 t = case t of (x,y) -> f x y l n (x,y) = l (n-1) (x,y) s' = -- To prevent inlining large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ large $ s bar1 :: Int -> (a -> b -> Bool) -> a -> b -> Bool bar1 s f x y = foo s f (x,y) bar2 :: Int -> (a -> b -> Bool) -> a -> b -> Bool bar2 s f x y = foo (s + 1) f (x,y) }}} This needs to rounds of !SpecConstr to specialize `foo` for the `(x,y)` call pattern; in the first round, `l` is specialized, then the (then non- recursive `l`) gets inlined into `foo`, then `foo` gets specialized. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14844#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler