PPC cross-compile impossible happened

While trying to build a powerpc targetted GHC cross compiler from current GIT head version I saw the impossible happened message below:

echo 'export LD_LIBRARY_PATH=":$LD_LIBRARY_PATH"' >> inplace/bin/genapply
echo 'exec "$executablename" ${1+"$@"}'                     >> inplace/bin/genapply
chmod +x                                                     inplace/bin/genapply
"inplace/bin/ghc-stage1" -hisuf hi -osuf  o -hcsuf hc -static  -H64m -O0 -fasm    -package-name
ghc-prim-0.3.1.0 -hide-all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/
build -ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/dist-install/build -I
libraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/.    -optP-include -optPlibra
ries/ghc-prim/dist-install/build/autogen/cabal_macros.h -package rts-1.0 -package-name ghc-prim
-XHaskell98 -XCPP -XMagicHash -XForeignFunctionInterface -XUnliftedFFITypes -XUnboxedTuples -XEm
ptyDataDecls -XNoImplicitPrelude -O -fasm  -no-user-package-db -rtsopts      -odir libraries/ghc
-prim/dist-install/build -hidir libraries/ghc-prim/dist-install/build -stubdir libraries/ghc-pri
m/dist-install/build  -dynamic-too -c libraries/ghc-prim/./GHC/Classes.hs -o libraries/ghc-prim/
dist-install/build/GHC/Classes.o -dyno libraries/ghc-prim/dist-install/build/GHC/Classes.dyn_o
ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 7.7.20130407 for powerpc-e500v2-linux):
        allocateRegsAndSpill: Cannot read from uninitialized register
    %vI_nvZF

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

make[1]: *** [libraries/ghc-prim/dist-install/build/GHC/Classes.o] Error 1
make[1]: *** Deleting file `libraries/ghc-prim/dist-install/build/GHC/Classes.o'