int DominatorGraph::semi_dominators (int r) {
int bsize = n+1;
int *buffer = new int [5*bsize];
int *label2pre = &buffer[0];
int *pre2label = &buffer[bsize];
int *parent = &buffer[2*bsize];
//int *ancestor = &buffer[3*bsize];
int *label = &buffer[3*bsize];
int *semi = &buffer[4*bsize];
resetcounters();
int npdom = 0; //number of vertices dominated by their parent
int i;
for (i=0; i<=n; i++) {
label[i] = semi[i] = i;
//ancestor[i] = 0;
}
int N = preDFSp (r, label2pre, pre2label, parent);
for (i=N; i>=2; i--) {
int w = pre2label[i];
int *p, *stop;
getInBounds(w,p,stop);
for (; p<stop; p++) {
int v = label2pre[*p];
if (v) {
int u;
//if (!ancestor[v]) {u=v;}
//if (!parent[v]) {u=v;}
if (v<=i) {u=v;} //u is an ancestor of i
else {
//rcompress(v,ancestor,semi,label);
rcompress(v,parent,semi,label,i);
u = label[v];
}
if (semi[u]<semi[i]) semi[i] = semi[u];
}
}
//if (semi[i]==parent[i]) npdom++;
incs();
//ancestor[i] = parent[i];
}
delete [] buffer;
return npdom;
}
void DominatorGraph::slt (int r, int *idom) {
int bsize = n+1;
int *buffer = new int [6*bsize];
int *pre2label = &buffer[0];
int *parent = &buffer[bsize];
int *semi = &buffer[2*bsize];
int *label = &buffer[3*bsize];
int *dom = &buffer[4*bsize];
int *ubucket = &buffer[5*bsize];
int *label2pre = idom; //indexed by label
resetcounters();
int i;
for (i=n; i>=0; i--) {
label[i] = semi[i] = i;
ubucket[i] = 0;
}
//pre-dfs
int N = preDFSp (r, label2pre, pre2label, parent);
// process the vertices in reverse preorder
for (i=N; i>1; i--) {
/*---------------------
| process i-th bucket
*--------------------*/
for (int v=ubucket[i]; v; v=ubucket[v]) {
rcompress (v, parent, semi, label, i);
int u = label[v];
incc();
dom[v] = (semi[u]<semi[v]) ? u : i;
}
//no need to empty the bucket
/*---------------------------------------------
| check incoming arcs, update semi-dominators
*--------------------------------------------*/
int *p, *stop;
getInBounds (pre2label[i], p, stop);
for (; p<stop; p++) {
int v = label2pre[*p];
incc();
if (v) {
int u;
incc();
if (v<=i) {u=v;} //v is an ancestor of i
else {
rcompress (v, parent, semi, label, i);
u = label[v];
}
incc();
if (semi[u]<semi[i]) semi[i] = semi[u];
}
}
/*---------------------------
| process candidate semidom
*--------------------------*/
int s = semi[i];
incc();
if (s!=parent[i]) { //if semidominator n not parent: add i to s's bucket
ubucket[i] = ubucket[s];
ubucket[s] = i;
} else {
dom[i] = s; //semidominator is parent: s is a candidate dominator
}
}
/*------------------
| process bucket 1
*-----------------*/
for (int v=ubucket[1]; v; v=ubucket[v]) dom[v]=1;
/*---------------
| recover idoms
*--------------*/
dom[1] = 1;
idom[r] = r;
for (i=2; i<=N; i++) {
incc();
if (dom[i]!=semi[i]) dom[i]=dom[dom[i]]; //make relative absolute
idom[pre2label[i]] = pre2label[dom[i]];
}
delete [] buffer; //cleanup stuff
}
