#12370: Implement LetUp in DmdAnal (or document why we do not do it) -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The paper “Modular, Higher-Order Cardinality Analysis in Theory and Practice” has two rules for analizing let-bindings: LetDown, used for functions, that determines the function’s strictness signature, and passes it down, and LetUp, used for thunks, which uses the demand coming from the scope. The implementation uses only LetDown for all let-bindings. I wonder why this is so. I implemented something that looks like LetUp and will validate and performance-test it soon, in order to either make the implementation match the analysis, or alternatively document why this is the case. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12370 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler