#6087: Join points need strictness analysis -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: infoneeded Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 7.4.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): We decided to put this on hold at the meeting. Just a small update: the case in comment:27 seems to be a limitation with the current demand analyser. It sometimes introduces reboxing that can't be eliminated by the simplifier. Example: {{{ {-# NOINLINE check #-} check :: Int -> Bool check !n = True f_ :: Int -> Int f_ n = if check n then n else n * f_ (n - 1) }}} even after simplifications we rebox the argument: {{{ Rec { -- RHS size: {terms: 17, types: 3, coercions: 0, joins: 0/0} $wf_ $wf_ = \ ww_s28U -> case check (I# ww_s28U) of { False -> case $wf_ (-# ww_s28U 1#) of ww1_s28Y { __DEFAULT -> *# ww_s28U ww1_s28Y }; True -> ww_s28U } end Rec } }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/6087#comment:31 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler