RegisterSpecList ssaSetToSpecs(IntSet ssaSet) {
    RegisterSpecList result = new RegisterSpecList(ssaSet.elements());

    IntIterator iter = ssaSet.iterator();

    int i = 0;
    while (iter.hasNext()) {
      result.set(i++, getDefinitionSpecForSsaReg(iter.next()));
    }

    return result;
  }
Converts a bit set of SSA registers into a RegisterSpecList containing the definition specs of
all the registers.

@param ssaSet {@code non-null;} set of SSA registers
@return list of RegisterSpecs as noted above
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/back/FirstFitLocalCombiningAllocator.java