[GHC] #8472: Primitive string literals prevent optimization

[GHC]

#8472: Primitive string literals prevent optimization
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        Reporter:  akio              |                Owner:  gridaphobe
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.6.3
      Resolution:                    |             Keywords:  newcomer
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Runtime           |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by akio):

 Replying to [comment:10 gridaphobe]:
 > Does your patch validate? I just noticed this afternoon that although my
 patch works for the example and parts of nofib, it causes a linker error
 when building ghc-stage2, due to undefined symbols. I'm setting the label
 for the string literal a bit differently from you, so your patch might be
 fine.

 I don't get link errors, but I do get several failures when I run `make
 slow` in `testsuite/`. Some of the failures look harmless (the expected
 output has to be adjusted) but I'll need to look more carefully at other
 failures.

 >
 > My CoreLint patch is at
 https://github.com/ghc/ghc/compare/master...gridaphobe:T8472#diff-
 9ad7456ebf7fad38de8b24ddceb9bb3c. Do you want to submit your patch + my
 CoreLint pass, that ought to make for a complete patch :)

 Thanks, I've taken your patch to CoreLint. I'm happy to sort out the
 remaining issues and submit a Differential revision, but I won't have much
 time to work on this until this weekend. Feel free to go ahead and do it
 yourself if you like. In any case, my work-in-progress branch can be found
 at https://github.com/takano-akio/ghc/commits/top-level-string.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8472#comment:12>
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