[GHC] #15226: GHC doesn't know that seq# produces something in WHNF

[GHC]

#15226: GHC doesn't know that seq# produces something in WHNF
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4796
       Wiki Page:                    |
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Comment (by David Feuer <David.Feuer@…>):

 In [changeset:"d964b054d530ea9e29ed051fdf2b49a6afe465fb/ghc" d964b05/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="d964b054d530ea9e29ed051fdf2b49a6afe465fb"
 Let the simplifier know that seq# forces

 Add a special case in `simplAlt` to record that the result of
 `seq#` is in WHNF.

 Reviewers: simonmar, bgamari, simonpj

 Reviewed By: simonpj

 Subscribers: simonpj, rwbarton, thomie, carter

 GHC Trac Issues: #15226

 Differential Revision: https://phabricator.haskell.org/D4796
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15226#comment:5>
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