RegAlloc != (RegisterRegAlloc::FunctionPassCtor)&createFastRegisterAllocator)

      RegAlloc != (RegisterRegAlloc::FunctionPassCtor)&createFastRegisterAllocator &&
      RegAlloc != (RegisterRegAlloc::FunctionPassCtor)&createSimpleRegisterAllocator)

  initializeRegAllocSimplePass(Registry);

  RegAllocSimple.cpp

void initializeRegAllocSimplePass(PassRegistry&);

  FunctionPass *createSimpleRegisterAllocator();

      (void) llvm::createSimpleRegisterAllocator();