[GHC] #14986: ghc panics when compiling stage 2

30 Mar 2018

      #14986: ghc panics when compiling stage 2
-------------------------------------+-------------------------------------
           Reporter:  terrorjack     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Build System   |           Version:  8.5
           Keywords:                 |  Operating System:  Windows
       Architecture:  x86_64         |   Type of failure:  Building GHC
  (amd64)                            |  failed
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 I'm compiling a recent commit (0017a7b618353bf984d701f6d8ee2810a425e5b3),
 yet ghc always panics when ghc-stage1 is compiling ghc-prim. The error is
 as follows:

 {{{
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/CString.hs -o libraries/ghc-prim/dist-
 install/build/GHC/CString.o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/IntWord64.hs -o libraries/ghc-prim/dist-
 install/build/GHC/IntWord64.o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-all-packages -i
 -ilibraries/base/. -ilibraries/base/dist-install/build -Ilibraries/base
 /dist-install/build -ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/dist-install/build/./autogen -Ilibraries/base/include
 -Ilibraries/base/dist-install/build/include    -optP-include
 -optPlibraries/base/dist-install/build/./autogen/cabal_macros.h -package-
 id ghc-prim-0.5.2.0 -package-id integer-simple-0.1.1.1 -package-id rts
 -this-unit-id base -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-
 trustworthy-safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances
 -odir libraries/base/dist-install/build -hidir libraries/base/dist-
 install/build -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/Base.hs-boot -o libraries/base/dist-
 install/build/GHC/Base.o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-all-packages -i
 -ilibraries/base/. -ilibraries/base/dist-install/build -Ilibraries/base
 /dist-install/build -ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/dist-install/build/./autogen -Ilibraries/base/include
 -Ilibraries/base/dist-install/build/include    -optP-include
 -optPlibraries/base/dist-install/build/./autogen/cabal_macros.h -package-
 id ghc-prim-0.5.2.0 -package-id integer-simple-0.1.1.1 -package-id rts
 -this-unit-id base -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-
 trustworthy-safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances
 -odir libraries/base/dist-install/build -hidir libraries/base/dist-
 install/build -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/Real.hs-boot -o libraries/base/dist-
 install/build/GHC/Real.o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-all-packages -i
 -ilibraries/base/. -ilibraries/base/dist-install/build -Ilibraries/base
 /dist-install/build -ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/dist-install/build/./autogen -Ilibraries/base/include
 -Ilibraries/base/dist-install/build/include    -optP-include
 -optPlibraries/base/dist-install/build/./autogen/cabal_macros.h -package-
 id ghc-prim-0.5.2.0 -package-id integer-simple-0.1.1.1 -package-id rts
 -this-unit-id base -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-
 trustworthy-safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances
 -odir libraries/base/dist-install/build -hidir libraries/base/dist-
 install/build -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/IO.hs-boot -o libraries/base/dist-
 install/build/GHC/IO.o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-all-packages -i
 -ilibraries/base/. -ilibraries/base/dist-install/build -Ilibraries/base
 /dist-install/build -ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/dist-install/build/./autogen -Ilibraries/base/include
 -Ilibraries/base/dist-install/build/include    -optP-include
 -optPlibraries/base/dist-install/build/./autogen/cabal_macros.h -package-
 id ghc-prim-0.5.2.0 -package-id integer-simple-0.1.1.1 -package-id rts
 -this-unit-id base -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-
 trustworthy-safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances
 -odir libraries/base/dist-install/build -hidir libraries/base/dist-
 install/build -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./Data/Semigroup/Internal.hs-boot -o libraries/base/dist-
 install/build/Data/Semigroup/Internal.o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/Tuple.hs -o libraries/ghc-prim/dist-
 install/build/GHC/Tuple.o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/Magic.hs -o libraries/ghc-prim/dist-
 install/build/GHC/Magic.o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/CString.hs -o libraries/ghc-prim/dist-
 install/build/GHC/CString.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/IntWord64.hs -o libraries/ghc-prim/dist-
 install/build/GHC/IntWord64.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-
 all-packages -i -ilibraries/base/. -ilibraries/base/dist-install/build
 -Ilibraries/base/dist-install/build -ilibraries/base/dist-
 install/build/./autogen -Ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/include -Ilibraries/base/dist-install/build/include
 -optP-include -optPlibraries/base/dist-
 install/build/./autogen/cabal_macros.h -package-id ghc-prim-0.5.2.0
 -package-id integer-simple-0.1.1.1 -package-id rts -this-unit-id base
 -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-safe
 -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/base/dist-install/build -hidir libraries/base/dist-install/build
 -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/Base.hs-boot -o libraries/base/dist-
 install/build/GHC/Base.p_o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-
 all-packages -i -ilibraries/base/. -ilibraries/base/dist-install/build
 -Ilibraries/base/dist-install/build -ilibraries/base/dist-
 install/build/./autogen -Ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/include -Ilibraries/base/dist-install/build/include
 -optP-include -optPlibraries/base/dist-
 install/build/./autogen/cabal_macros.h -package-id ghc-prim-0.5.2.0
 -package-id integer-simple-0.1.1.1 -package-id rts -this-unit-id base
 -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-safe
 -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/base/dist-install/build -hidir libraries/base/dist-install/build
 -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/Real.hs-boot -o libraries/base/dist-
 install/build/GHC/Real.p_o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-
 all-packages -i -ilibraries/base/. -ilibraries/base/dist-install/build
 -Ilibraries/base/dist-install/build -ilibraries/base/dist-
 install/build/./autogen -Ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/include -Ilibraries/base/dist-install/build/include
 -optP-include -optPlibraries/base/dist-
 install/build/./autogen/cabal_macros.h -package-id ghc-prim-0.5.2.0
 -package-id integer-simple-0.1.1.1 -package-id rts -this-unit-id base
 -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-safe
 -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/base/dist-install/build -hidir libraries/base/dist-install/build
 -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./GHC/IO.hs-boot -o libraries/base/dist-
 install/build/GHC/IO.p_o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id base-4.11.0.0 -hide-
 all-packages -i -ilibraries/base/. -ilibraries/base/dist-install/build
 -Ilibraries/base/dist-install/build -ilibraries/base/dist-
 install/build/./autogen -Ilibraries/base/dist-install/build/./autogen
 -Ilibraries/base/include -Ilibraries/base/dist-install/build/include
 -optP-include -optPlibraries/base/dist-
 install/build/./autogen/cabal_macros.h -package-id ghc-prim-0.5.2.0
 -package-id integer-simple-0.1.1.1 -package-id rts -this-unit-id base
 -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-safe
 -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/base/dist-install/build -hidir libraries/base/dist-install/build
 -stubdir libraries/base/dist-install/build -split-objs   -c
 libraries/base/./Data/Semigroup/Internal.hs-boot -o libraries/base/dist-
 install/build/Data/Semigroup/Internal.p_o-boot
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/Tuple.hs -o libraries/ghc-prim/dist-install/build/GHC/Tuple.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/Magic.hs -o libraries/ghc-prim/dist-install/build/GHC/Magic.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/Classes.hs -o libraries/ghc-prim/dist-
 install/build/GHC/Classes.o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/./GHC/Debug.hs -o libraries/ghc-prim/dist-
 install/build/GHC/Debug.o
 "inplace/bin/ghc-stage1.exe" -hisuf hi -osuf  o -hcsuf hc -static  -O
 -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-all-packages -i
 -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries
 /ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen
 -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-
 install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-
 prim -XHaskell2010 -O2  -no-user-package-db -rtsopts  -Wno-trustworthy-
 safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir
 libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-
 install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs
 -c libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.hs -o
 libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/Classes.hs -o libraries/ghc-prim/dist-
 install/build/GHC/Classes.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-
 prim/./GHC/Debug.hs -o libraries/ghc-prim/dist-install/build/GHC/Debug.p_o
 "inplace/bin/ghc-stage1.exe" -hisuf p_hi -osuf  p_o -hcsuf p_hc -static
 -prof -eventlog  -O -H64m -Wall      -this-unit-id ghc-prim-0.5.2.0 -hide-
 all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-
 install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim
 /dist-install/build/./autogen -Ilibraries/ghc-prim/dist-
 install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include
 -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h
 -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O2  -no-user-
 package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags
 -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-
 install/build -hidir libraries/ghc-prim/dist-install/build -stubdir
 libraries/ghc-prim/dist-install/build -split-objs   -c libraries/ghc-prim
 /dist-install/build/GHC/PrimopWrappers.hs -o libraries/ghc-prim/dist-
 install/build/GHC/PrimopWrappers.p_o
 ghc-stage1.exe: panic! (the 'impossible' happened)
   (GHC version 8.5.20180329 for x86_64-unknown-mingw32):
         Each block should be reachable from only one ProcPoint

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 make[1]: *** [libraries/ghc-prim/ghc.mk:4: libraries/ghc-prim/dist-
 install/build/GHC/Classes.o] Error 1
 make[1]: *** Waiting for unfinished jobs....
 ghc-stage1.exe: panic! (the 'impossible' happened)
   (GHC version 8.5.20180329 for x86_64-unknown-mingw32):
         Each block should be reachable from only one ProcPoint

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 make[1]: *** [libraries/ghc-prim/ghc.mk:4: libraries/ghc-prim/dist-
 install/build/GHC/Classes.p_o] Error 1
 make: *** [Makefile:127: all] Error 2
 }}}

 I'm using the following build.mk for those builds here:

 {{{
 GhcEnableTablesNextToCode = NO
 INTEGER_LIBRARY           = integer-simple
 SRC_HC_OPTS               = -O -H64m
 GhcStage1HcOpts           = -O
 GhcStage2HcOpts           = -O2
 GhcLibHcOpts              = -O2
 BUILD_PROF_LIBS           = YES
 SplitObjs                 = YES
 SplitSections             = NO
 BUILD_SPHINX_HTML         = YES
 BUILD_SPHINX_PDF          = NO
 HADDOCK_DOCS              = YES
 EXTRA_HADDOCK_OPTS        += --quickjump --hyperlinked-source

 }}}

 Still working to figure out a minimal combination of the build flags to
 trigger a similar error. Meanwhile, has anyone seen a similar error for a
 different commit/platform/build config?

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14986
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler