new warnings in r58273

/Volumes/mrs5/net/llvm/llvm/lib/CodeGen/PreAllocSplitting.cpp: In member function ‘bool<unnamed>::PreAllocSplitting::SplitRegLiveInterval(llvm::LiveInterval*)’:
/Volumes/mrs5/net/llvm/llvm/lib/CodeGen/PreAllocSplitting.cpp:546: warning: ‘SS’ may be used uninitialized in this function