#13193: Integer (gmp) performance regression? -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: 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 j.waldmann): Hi. * how to reproduce: add the type declaration that prevents the defaulting {{{ a :: Int -> ST s Int -> ST s Int -> ST s Int -> ST s Int -> ST s Int -> ST s Int` }}} * how big the change is {{{ ghc-6.12.3: Int: 1.28 sec Integer: 1.56 sec ghc-8.0.2 : Int: 1.30 sec Integer: 2.30 sec }}} * "Integer fit in Int" - when I replace Integer by Int, the program produces the exact same result, so I assume there were no overflows. When I replace the numerals 1, -1 by something really large (+/- 1000000000000000000), the execution path should be identical (affine transformation). The Int result does no longer agree with the Integer result, and the Integer runtime goes up slightly. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13193#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler