#15751: GHC takes huge amounts of memory and compile time when compiling ZipWith from accelerate -------------------------------------+------------------------------------- Reporter: tdammers | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | performance bug Test Case: Compile | Blocked By: `Data.Array.Accelerate.Test.NoFib.Prelude.ZipWith`| from `accelerate-1.2.0` | Blocking: | Related Tickets: #15488 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In #15488, we found that GHC takes huge amounts of memory by building up excessively large amounts of Core. Looking a the `Data.Array.Accelerate.Analysis.Hash` module there, the problem seems to be due to excessive (and unproductive) inlining. However, the `Data.Array.Accelerate.Test.NoFib.Prelude.ZipWith` module *also* takes a very large amount of time and memory to compile, and while it also builds up huge amounts of Core in unproductive ways, the blowup happens in a different step. https://github.com/AccelerateHS/accelerate/issues/428#issuecomment-425019263 has a build log that points at the first round of `Specialise` as the culprit. Just like #15488, this problem seems to trace back to GHC 8.0.2 at least, possibly further. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15751 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler