[GHC] #8834: 64-bit windows cabal.exe segfaults in GC

[GHC]

#8834: 64-bit windows cabal.exe segfaults in GC
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        Reporter:  awson          |            Owner:
            Type:  bug            |           Status:  patch
        Priority:  highest        |        Milestone:  7.8.1
       Component:  Compiler       |          Version:  7.8.1-rc2
      Resolution:                 |         Keywords:
Operating System:  Windows        |     Architecture:  x86_64 (amd64)
 Type of failure:  Runtime crash  |       Difficulty:  Unknown
       Test Case:                 |       Blocked By:
        Blocking:                 |  Related Tickets:
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Comment (by simonpj):

 So where are we on this?

  * Simon M says "here is the broken bit of code" (comment 35), and then
 says "I misread" (comment 38).  Does that mean that the broken bit of code
 isn't broken?

  * If we use Karel's reversion patch (between comments 2 and 3 above) does
 that cure all known crashes?  I confirm that it ''does'' fix my own "ghc-
 stage2 segfaults" problem, reported in #8870.  But what about the hello-
 world problem in #8834, and Ganesh's new report in #8890?

  * If reverting the `CmmSink` change does in fact solve the problem, we
 should probably go ahead and revert it, and un-block the GHC 7.8 release.

  * But even if we do that we are still stuck with not knowing WHY it
 solves the problem. Perhaps the patch was fine, but it exposes a problem
 somewhere else?  And we really want the `CmmSink` improvements.   We
 really need someone to dig into it with GDB.  Austin, can you get a
 Windows box on the network that exhibits the bug, so that Simon M can
 crank up gdb?

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8834#comment:39>
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