#10148: Optimization causes repeated computation -------------------------------------+------------------------------------- Reporter: akio | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- The attached program, when compiled with `-O0`, calls `array_adjust` 6 times and hence prints 6 lines of trace output. However, with `-O1`, it prints 37 lines of trace output instead. Moreover, this number grows quadratically rather than linearly when I increase the value of `n`. `-fno-state-hack` did not help. I can reproduce the issue with both GHC 7.8.4 and 7.10.0.20150123. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10148 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler