/**
* @return an integer telling which predecessor of Y in CFG is X. The jth operand of a
* phi-function in Y corresponds to the jth predecessor of Y from the listing of the in edges
* of Y
*/
private int whichPred(BasicBlock X, BasicBlock Y) {
int j = 0;
for (BasicBlock P : cfg.getPredecessors(X)) {
if (P.equals(Y)) {
return j;
}
j++;
}
throw new IllegalArgumentException("X is not a predecessor of Y");
}
