[GHC] #9400: poor performance when compiling modules with many Text literals at -O1

[GHC]

#9400: poor performance when compiling modules with many Text literals at -O1
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              Reporter:  rwbarton    |            Owner:
                  Type:  bug         |           Status:  closed
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:  invalid     |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Compile-    |       Blocked By:
  time performance bug               |  Related Tickets:  #9370
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 Replying to [comment:4 simonpj]:
 > Another possibility might be to remove the special behaviour of
 desugaring strings from GHC.  Why is it there?

 I was guessing that perhaps the generated code is smaller for a one-
 character list than for a call to `unpackCString#`. But if that's true,
 it's not a very good reason to put that logic in the desugarer; we could
 rewrite `unpackCString# "a"` to `'a' : []` in a later optimizer pass,
 after RULES have fired.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9400#comment:6>
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