[GHC] #9155: O2: allocateRegsAndSpill: Cannot read from uninitialized register %vI_s154O (GHC version 7.8.2 for x86_64-unknown-linux)

[GHC]

#9155: O2: allocateRegsAndSpill: Cannot read from uninitialized register %vI_s154O
(GHC version 7.8.2 for x86_64-unknown-linux)
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        Reporter:  slyfox              |            Owner:  simonmar
            Type:  bug                 |           Status:  new
        Priority:  highest             |        Milestone:  7.8.3
       Component:  Compiler (NCG)      |          Version:  7.8.2
      Resolution:                      |         Keywords:
Operating System:  Unknown/Multiple    |     Architecture:  x86_64 (amd64)
 Type of failure:  Compile-time crash  |       Difficulty:  Unknown
       Test Case:                      |       Blocked By:
        Blocking:                      |  Related Tickets:
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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"e577a52363ee7ee8a07f1d863988332ae8fbf2e4/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="e577a52363ee7ee8a07f1d863988332ae8fbf2e4"
 Fix discarding of unreachable code in the register allocator (#9155)

 A previous fix to this was wrong: f5879acd018494b84233f26fba828ce376d0f81d
 and left some unreachable code behind.  So rather than try to be clever
 and
 do this at the same time as the strongly-connected-component analysis, I'm
 doing a separate reachability pass first.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9155#comment:8>
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