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

[GHC]

#8832: Constant-folding regression wrt `clearBit (bit 0) 0 `
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              Reporter:  hvr         |            Owner:  thoughtpolice
                  Type:  bug         |           Status:  closed
              Priority:  high        |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.8.1-rc2
            Resolution:  fixed       |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Runtime     |       Blocked By:
  performance bug                    |  Related Tickets:
             Test Case:              |
  simplCore/should_compile/T8832     |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 Replying to [comment:18 hvr]:
 > Btw, now that I saw that commit, I've seen other testcases making use of
 the pre-defined `SIZEOF_HSWORD` (and there's also `WORD_SIZE_IN_BITS`) CPP
 symbol to test for wordsize. Would that have worked as well?

 Predefined by what? I tried `ghc -E -optP-dM -cpp foo.hs; cat foo.hspp` as
 suggested somewhere in the User's Guide to see what C preprocessor symbols
 were automatically defined and there wasn't anything like that among them.
 Or do you mean `#include`ing one of GHC's header files?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8832#comment:19>
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