public String toString() {
		String s = "<block " + label + " hdr=";

		if (header != null) {
			s += header.label();
		} else {
			s += "null";
		}

		switch (blockType) {
		case NON_HEADER:
			break;
		case IRREDUCIBLE:
			s += " irred";
			break;
		case REDUCIBLE:
			s += " red";
			break;
		}

		if (this == graph.source()) {
			return s + " source>";
		} else if (this == graph.init()) {
			return s + " init>";
		} else if (this == graph.sink()) {
			return s + " sink>";
		} else {
			return s + ">";
		}
	}