Profiled build broken
As of 6555c6bb the BuildFlavour=prof
build appears to be broken. The stage2 build appears to reproducibly fail with,
"inplace/bin/ghc-stage1" -hisuf p_hi -osuf p_o -hcsuf p_hc -static -prof -eventlog -O0 -H64m -Wall -this-unit-id ghc-8.1 -hide-all-packages -i -icompiler/basicTypes -icompiler/cmm -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar -icompiler/ghci -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main -icompiler/nativeGen -icompiler/parser -icompiler/prelude -icompiler/profiling -icompiler/rename -icompiler/simplCore -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn -icompiler/stranal -icompiler/typecheck -icompiler/types -icompiler/utils -icompiler/vectorise -icompiler/stage2/build -Icompiler/stage2/build -icompiler/stage2/build/./autogen -Icompiler/stage2/build/./autogen -Icompiler/. -Icompiler/parser -Icompiler/utils -Icompiler/../rts/dist/build -Icompiler/stage2 -optP-DGHCI -optP-include -optPcompiler/stage2/build/./autogen/cabal_macros.h -package-id array-0.5.1.1 -package-id base-4.9.0.0 -package-id binary-0.8.3.0 -package-id bytestring-0.10.8.1 -package-id containers-0.5.7.1 -package-id deepseq-1.4.2.0 -package-id directory-1.2.6.2 -package-id filepath-1.4.1.0 -package-id ghc-boot-8.1 -package-id ghci-8.1 -package-id hoopl-3.10.2.1 -package-id hpc-0.6.0.3 -package-id process-1.4.2.0 -package-id template-haskell-2.11.0.0 -package-id time-1.6.0.1 -package-id transformers-0.5.2.0 -package-id unix-2.7.2.0 -Wall -fno-warn-name-shadowing -this-unit-id ghc -XHaskell2010 -optc-DTHREADED_RTS -DGHCI_TABLES_NEXT_TO_CODE -DSTAGE=2 -Rghc-timing -O -fprof-auto-top -fprof-cafs -no-user-package-db -rtsopts -Wnoncanonical-monad-instances -odir compiler/stage2/build -hidir compiler/stage2/build -stubdir compiler/stage2/build -c compiler/codeGen/StgCmmMonad.hs -o compiler/stage2/build/StgCmmMonad.p_o -dyno compiler/stage2/build/StgCmmMonad.dyn_o
ghc-stage1: panic! (the 'impossible' happened)
(GHC version 8.1.20160912 for x86_64-unknown-linux):
kindPrimRep.go k0_10