#10148: Optimization causes repeated computation -------------------------------------+------------------------------------- Reporter: akio | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"9f0f99fd41ff82cc223d3b682703e508efb564d2/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="9f0f99fd41ff82cc223d3b682703e508efb564d2" Fix a long-standing bug in the demand analyser This patch fixes Trac #10148, an outright and egregious bug in the demand analyser. It is explained in Note [Demand on case-alternative binders] in Demand.hs. I did some other minor refactoring. To my astonishment I got some big compiler perf changes * perf/compiler/T5837: bytes allocated -76% * perf/compiler/T5030: bytes allocated -10% * perf/compiler/T3294: max bytes used -25% Happy days }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10148#comment:10> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler