[GHC] #8328: Crash at -O2: Cannot read from uninitialized register

[GHC]

#8328: Crash at -O2: Cannot read from uninitialized register
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       Reporter:  bos             |             Owner:
           Type:  bug             |            Status:  new
       Priority:  highest         |         Milestone:  7.8.1
      Component:  Compiler        |           Version:  7.7
       Keywords:                  |  Operating System:  Linux
   Architecture:  x86_64 (amd64)  |   Type of failure:  Compile-time crash
     Difficulty:  Unknown         |         Test Case:
     Blocked By:                  |          Blocking:
Related Tickets:                  |
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 I did a quick x86_64 compile of all of Hackage today using HEAD, and GHC
 is crashing when compiling the utf8-string package.

 {{{
 [2 of 7] Compiling Codec.Binary.UTF8.Generic (
 Codec/Binary/UTF8/Generic.hs, dist/dist-sandbox-
 4a6171fb/build/Codec/Binary/UTF8/Generic.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.7.20130915 for x86_64-unknown-linux):
         allocateRegsAndSpill: Cannot read from uninitialized register
     %vI_sa0l
 }}}

 To reproduce using utf8-string:

 {{{
 cabal get utf8-string
 cd utf8-string*
 ghc -XCPP -fforce-recomp -O2 --make -c Codec/Binary/UTF8/Generic.hs
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8328>
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