#10397: Compiler performance regression 7.6 -> 7.8 in elimCommonBlocks -------------------------------------+------------------------------------- Reporter: TobyGoodwin | Owner: Type: bug | Status: merge Priority: normal | Milestone: 7.10.2 Component: Compiler | Version: 7.8.4 Resolution: | Keywords: Operating System: Unknown/Multiple | performance Type of failure: None/Unknown | Architecture: Blocked By: | Unknown/Multiple Related Tickets: | Test Case: see ticket | Blocking: | Differential Revisions: Phab:D892 -------------------------------------+------------------------------------- Comment (by simonpj): That's a trememdous improvement, thanks Joachim. That said, 20% of compilation time in one, relatively minor, optimisation is far too much. I wonder how we could improve matters further? For example, the bigger the block the less likely it is to be identical, but the more expensive it is to compare (I guess). Maybe we can cut off at some block size? Also why are you comparing (hash, list of successor labels) rather than just including the successor labels in the hash? Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10397#comment:22 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler