#13789: Look into haddock performance regressions due to desugaring on -fno-code -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- c9eb4385aad248118650725b7b699bb97ee21c0d enabled desugaring when GHC is invoked with `-fno-code` in order to resolve #10600. Unfortunately this causes GHC to do more (unnecessary) work when parsing for haddock, causing some rather significant allocations regressions in the haddock performance tests, {{{ bytes allocated value is too high: Expected haddock.base(normal) bytes allocated: 25592972912 +/-5% Lower bound haddock.base(normal) bytes allocated: 24313324266 Upper bound haddock.base(normal) bytes allocated: 26872621558 Actual haddock.base(normal) bytes allocated: 27868466432 Deviation haddock.base(normal) bytes allocated: 8.9 % *** unexpected stat test failure for haddock.base(normal) =====> haddock.Cabal(normal) 6 of 7 [0, 0, 0] bytes allocated value is too high: Expected haddock.Cabal(normal) bytes allocated: 18269309128 +/-5% Lower bound haddock.Cabal(normal) bytes allocated: 17355843671 Upper bound haddock.Cabal(normal) bytes allocated: 19182774585 Actual haddock.Cabal(normal) bytes allocated: 22294859000 Deviation haddock.Cabal(normal) bytes allocated: 22.0 % *** unexpected stat test failure for haddock.Cabal(normal) =====> haddock.compiler(normal) 7 of 7 [0, 0, 0] bytes allocated value is too high: Expected haddock.compiler(normal) bytes allocated: 52762752968 +/-10% Lower bound haddock.compiler(normal) bytes allocated: 47486477671 Upper bound haddock.compiler(normal) bytes allocated: 58039028265 Actual haddock.compiler(normal) bytes allocated: 65378619232 Deviation haddock.compiler(normal) bytes allocated: 23.9 % *** unexpected stat test failure for haddock.compiler(normal) }}} Work out how to mitigate this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13789 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler