// Create 4 basic blocks, corresponding to and if/then/else clause
// with a CFG that looks like a diamond
public int buildDiamond(int start) {
int bb0 = start;
new BasicBlockEdge(cfg, bb0, bb0 + 1);
new BasicBlockEdge(cfg, bb0, bb0 + 2);
new BasicBlockEdge(cfg, bb0 + 1, bb0 + 3);
new BasicBlockEdge(cfg, bb0 + 2, bb0 + 3);
return bb0 + 3;
}