7.8 RC1 unregisterised fails selfbootstrap on 64 bit Linux

Selfbootstrap of an unregisterised ghc fails on 64 bit PowerPC and AMD but not on 32 bit (PowerPC or Intel):

[10021s] "inplace/bin/ghc-stage1" -static  -H32m -O -optc-mminimal-toc -optc-fno-builtin -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -package-name rts -optc-DNOSMP -dcmm-lint      -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen           -O2    -c rts/StgStartup.cmm -o rts/dist/build/StgStartup.o
[10021s] ghc-stage1: panic! (the 'impossible' happened)
[10021s]   (GHC version 7.8.0.20140220 for powerpc64-unknown-linux):
[10021s] 	no ppt
[10021s]     ct ct: _cj::P64 = P64[(old + 16)];
[10021s]            _ck::P64 = R1;
[10021s]            goto cl;
[10021s] 
[10021s] Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

I disabled gcc's built in functions through -fno-builtin which got rid of a load of warnings (incompatible types for the built-ins) but still fails as shown above.

Trac metadata

Trac field	Value
Version	7.8.1-rc1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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