public OPT_BasicBlockEnumeration getBasicBlocks(OPT_BitVector bits) { return new BitSetBBEnum(this,bits);
public OPT_BasicBlockEnumeration getBasicBlocks() { return OPT_IREnumeration.forwardBE(this);
  public OPT_BasicBlockEnumeration getBasicBlocks(OPT_BitVector bits) {    return new BitSetBBEnum(this,bits);  }