[GHC] #15569: Constant folding optimises 1 into 3

[GHC]

#15569: Constant folding optimises 1 into 3
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        Reporter:  snowleopard       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1-beta1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9136             |  Differential Rev(s):  Phab:D5109
       Wiki Page:                    |
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Comment (by ChaiTRex):

 Apologies for the delay: I had no power for a while and had to restart.
 The results before the patch are attached and point out only this bug. The
 results after the patch point out no bugs:

 {{{

 }}}

 So, `Int`s look good on my end, at least up to an expression nesting depth
 of two (''i.e.'', up to something like `(a + b)*(c + d)`).

 For any future needs, I've put a newly-multithreaded version of the tester
 on GitHub at [https://github.com/ChaiTRex/ConstantFoldingTest
 ChaiTRex/ConstantFoldingTest].

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15569#comment:14>
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