#14152: Float exit paths out of recursive functions -------------------------------------+------------------------------------- Reporter: nomeata | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #14137 #10918 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): Thanks for the guidance, that nailed it: * The code `isJoinId bndr, isOneOcc (idOccInfo bndr), occ_in_lam (idOccInfo bndr)` reliably detects an exit join point now, it seems. (I guess this deserves its own function `isExitJoinPoint`) * When I create the join point, I add the correct `OccInfo`, so that this is there even before OccurAnal runs the next time. * In `simplLetUnfolding`, when I detect an exit join point, I do not creating an unfolding. This prevents unfolding in `completeCall` and `postInlineUnconditionally`. * In `preInlineUnconditionally` I check for exit join points explicityly. Maybe it would be cleaner to leave the unfolding alone and simply check for `isExitJoinPoint` in all three places… but no, the simplifier seems to throw away the `idOccInfo`. So better stick to not creating an unfolding. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14152#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler