[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)
---------------------------------------+----------------------------------
        Reporter:  slyfox              |            Owner:
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:
       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:
---------------------------------------+----------------------------------

Comment (by niklasl):

 The issue disappears when I revert commit
 f5879acd018494b84233f26fba828ce376d0f81d

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9155#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler