[GHC] #14737: Improve performance of Simplify.simplCast

[GHC]

#14737: Improve performance of Simplify.simplCast
-------------------------------------+-------------------------------------
        Reporter:  tdammers          |                Owner:  goldfire
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11735 #14683     |  Differential Rev(s):  Phab:D4385
       Wiki Page:                    |  Phab:D4568
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"2a5bdd9adb1cb4afecd3303f0cfcc224be5ce745/ghc" 2a5bdd9/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="2a5bdd9adb1cb4afecd3303f0cfcc224be5ce745"
 Remove unnecessary check in simplCast

 The coercion optimizer will take care of it anyway, and the check is
 prohibitively expensive.

 See Trac #14737.

 Reviewers: bgamari

 Subscribers: simonpj, thomie, carter

 Differential Revision: https://phabricator.haskell.org/D4568
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14737#comment:30>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler