Thanks for working on this. If you think that HEAD is compiling code
#13193: Integer (gmp) performance regression? -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: newcomer Operating System: Linux | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rwbarton): Replying to [comment:9 simonpj]: that is sub-optimal, can you boil it out to an example? But if it is just that the original Haskell forces GHC to generate bad code, then yes let's just improve the implementation of `minusInteger`.
I couldn't quite figure out which is the case from the notes above.
Please disregard the second bullet point of comment:6. I was comparing compiled code from 7.10 with the source code from HEAD, but there was a change that I didn't know about in the source between those versions. My hope is that this change (Phab:D2278 from this past May) will bring HEAD's performance back in line with 7.8's, but I don't have a suitable setup to test that at the moment. If it does so then we can close this ticket (optionally: after landing Phab:D3034, improving the implementation of `minusInteger` slightly). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13193#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler