#15304: Huge increase of compile time and memory use from 8.0.2 to 8.2.2 or 8.4.2 -------------------------------------+------------------------------------- Reporter: NathanWaivio | Owner: tdammers Type: bug | Status: new Priority: high | Milestone: 8.6.1 Component: Compiler | Version: 8.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by NathanWaivio): I have found an undocumented flag: "-fno-worker-wrapper". When enabled the original code compiles in 43.20 seconds (37x improvement in time), and uses 660MB max (48x improvement in space) with GHC 8.4.2. All of the tests pass for the library and the benchmark still performs at the improved speed. It seems like the Worker/Wrapper Transformation is causing issues with this code. Why is that? Perhaps Worker/Wrapper shouldn't be run in certain circumstances. What do you think? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15304#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler