Re: [GHC] #14068: Loopification using join points

#14068: Loopification using join points -------------------------------------+------------------------------------- Reporter: nomeata | Owner: nomeata Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #13966 #14067 | Differential Rev(s): Phab:D3811 Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Joachim, where are we on loopification? I think you have `wip/T14068` with this commit {{{ commit b4ab3a5f1fa051be9c5689f7ecef16458b2d700d Author: Joachim Breitner Date: Fri Aug 4 15:34:11 2017 -0400 Prevent inlining of loopified programs Previously, a recursive function is not inlineable. After loopification, it turns into a non-recursive function, and suddenly it is. While this is in general desirable, it has many knock-on effects, which makes it hard to evaluate and debug loopification. Therefore, this commit (tries to) prevent this inlining. When this results in no unfixable regressions, then we can tackle the next step. It is surprisingly hard to reliably prevent inlining, it seems, so I have been playing whack-a-mole a bit: * simpl_binds has two copies of the ids around, one in the env and one in the AST. If maybeLoopify changes only one of them, then things go wrong. Worked-around that for now, but probably not ideal. TODO: Apply maybeLoopify before entering simplTopBinds * Also, worker-wrapper needs to preserve the no-inlining better }}} But I think it's in limbo? Or has it been overtaken by events? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14068#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler