#14272: GHC goes out of memory while compiling simple program with optimizations -------------------------------------+------------------------------------- Reporter: 39aldo39 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- When compiling the following program with `ghc -O Main.hs`, GHC goes out of memory. {{{#!hs import Data.Bits (bit) main :: IO () main = putStrLn (show (f undefined)) f :: [Int] -> Int f = sum . zipWith ((+) . bit) [0..] . map undefined . scanl undefined undefined }}} I have 6 GB RAM and 8 GB swap free, so that shouldn't be the problem. It only happens with optimizations on, and it happens during a simplifier. Any simpler expressions do work. It even happens when `[0..]` is replaced by `take 1 [0..]`, but it compiles with `take 0 [0..]`. A straightforward workaround is to replace `zipWith f [0..]` by `\xs -> zipWith f [0..length xs] xs`. I ran into this problem when updating to GHC 8.2.1 from 8.0.2. But the given program doesn't compile on older versions as well. GHC 7.10.3 was the lowest version I could run before running into other problems. All GHC versions I tested come from the Debian repo. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14272 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler