private void addWorkIfNecessary(int offset, boolean blockStart) {
    if (!Bits.get(liveSet, offset)) {
      Bits.set(workSet, offset);
    }

    if (blockStart) {
      Bits.set(blockSet, offset);
    }
  }
Sets a bit in the work set, but only if the instruction in question isn't yet known to be
possibly-live.

@param offset offset to the instruction in question
@param blockStart {@code true} iff this instruction starts a basic block
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/code/BasicBlocker.java