[GHC] #8832: Constant-folding regression wrt `clearBit (bit 0) 0 `

[GHC]

#8832: Constant-folding regression wrt `clearBit (bit 0) 0 `
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                   Owner:  bgamari
            Type:  bug               |                  Status:  patch
        Priority:  high              |               Milestone:  8.0.1
       Component:  Core Libraries    |                 Version:  7.8.1-rc2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime           |               Test Case:
  performance bug                    |  simplCore/should_compile/T8832
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  Phab:D1255
-------------------------------------+-------------------------------------

Comment (by Austin Seipp <austin@…>):

 In [changeset:"cf90a1e14efb900f94a3824b242be1c38b16a563/ghc" cf90a1e/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="cf90a1e14efb900f94a3824b242be1c38b16a563"
 Add constant-folding rule for Data.Bits.bit

 This adds a constant-folding rule for `Integer`'s implementation of `bit`
 and
 fixes the `T8832` testcase. Fixes #8832.

 Reviewed By: simonpj, austin

 Differential Revision: https://phabricator.haskell.org/D1255

 GHC Trac Issues: #8832
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8832#comment:31>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler