private boolean isVersionZeroRegister(int ssaReg) {
    return ssaReg < ropRegCount;
  }
Returns true if this SSA register is a "version 0" register. All version 0 registers are
assigned the first N register numbers, where N is the count of original rop registers.

@param ssaReg the SSA register in question
@return true if it is a version 0 register.
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/SsaRenamer.java