#13873: Adding a SPECIALIZE at a callsite in Main.hs is causing a regression -------------------------------------+------------------------------------- Reporter: jberryman | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1-rc2 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: -------------------------------------+------------------------------------- Github user jmoy documents an issue with lack of specialization happening for INLINABLE functions in GHC 8.0 here: https://github.com/jmoy/testing- specialize . Testing on 8.2.1 it seems that specialization happened (although I didn't verify this in the core) as the result was 10x faster. But the odd thing to me was uncommenting the `SPECIALIZE` pragma at the callsite actually resulted in a significant regression: https://github.com/jmoy/testing-specialize/issues/1#issuecomment-310868360 Maybe GHC is choosing the worse manual partial specialization for some reason. I'm sorry I can't produce a better ticket for this at the moment. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13873 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler