private bool IsBackEdge(Region a, Region b)
{
return doms.DominatesStrictly(b, a);
}
private Region Dfs(Region n)
{
Debug.Print("DFS: visiting node {0}", n.Block.Name);
if (!IsCyclic(n))
{
return MatchAcyclic(n);
}
else
{
return MatchCyclic(n);
}
}
private bool IsCyclic(Region n)
{
return regionGraph.Predecessors(n).Any(pred => pred == n || IsBackEdge(pred, n));
}
private DominatorGraph<Region> BuildPostDoms()
{
var revGraph = new ReverseGraph(regionGraph);
var exitNode = new Region(new Block(proc, "DummyExitBlock")) { Type = RegionType.Tail };
revGraph.Nodes.Add(exitNode);
var tailRegions = regionGraph.Nodes.Where(n => n.Type == RegionType.Tail);
foreach (var r in tailRegions)
{
revGraph.AddEdge(exitNode, r);
}
return new DominatorGraph<Region>(revGraph, exitNode);
}