Re: [GHC] #16122: `round :: Double -> Int64` much slower than `fromIntegral @Int @Int64 . round`

7 Jan 2019

      #16122: `round :: Double -> Int64` much slower than `fromIntegral @Int @Int64 .
round`
-------------------------------------+-------------------------------------
        Reporter:  Fuuzetsu          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonpj):

 Finally, I still think it'd be clearer (i.e. easier to reason about what
 will ultimately happen) to call `roundDoubleInt` directly in the rule.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16122#comment:8
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler