[GHC] #11989: Performance bug reading large-exponent float without explicit type

#11989: Performance bug reading large-exponent float without explicit type -------------------------------------+------------------------------------- Reporter: bpearlmutter | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Runtime | Version: 7.10.3 System | Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Runtime (amd64) | performance bug Test Case: 1e1000000 :: | Blocked By: (RealFloat a => a) | Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{ $ time echo '1e700000' | ghci GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help Prelude> Infinity Prelude> Leaving GHCi. real 1m25.799s user 0m20.828s sys 0m9.624s $ time echo '1e700000::Double' | ghci GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help Prelude> Infinity Prelude> Leaving GHCi. real 0m0.196s user 0m0.120s sys 0m0.032s $ time echo 1e-800000 | ghci GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help Prelude> Killed real 2m8.879s user 0m6.684s sys 0m10.256s }}} Giving an explicit type `(RealFloat a => a)` doesn't make any difference. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11989 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11989: Performance bug reading large-exponent float without explicit type -------------------------------------+------------------------------------- Reporter: bpearlmutter | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.10.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: Runtime | Test Case: 1e1000000 :: performance bug | (RealFloat a => a) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by j.waldmann): This happens with 8-rc4 as well. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11989#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#11989: Performance bug reading large-exponent float without explicit type -------------------------------------+------------------------------------- Reporter: bpearlmutter | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Runtime System | Version: 7.10.3 Resolution: duplicate | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: Runtime | Test Case: 1e1000000 :: performance bug | (RealFloat a => a) Blocked By: | Blocking: Related Tickets: #9059, #5688, | Differential Rev(s): #5692, #7044 | Wiki Page: | -------------------------------------+------------------------------------- Changes (by thomie): * status: new => closed * resolution: => duplicate * related: => #9059, #5688, #5692, #7044 Comment: This is a real problem, but reported before as #9059 and others. Not much has been done in recent times to try to solve it. I'm closing this ticket, to not let discussion spread over multiple tickets. Please reopen if you disagree. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11989#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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