Efficient way to recursively calculate dominator tree?

Question

I\'m using the Lengauer and Tarjan algorithm with path compression to calculate the dominator tree for a graph where there are millions of nodes. The algorithm is quite complex

Answer 1

Could you elaborate on what sort of graph you're starting with? I don't see how there is any difference between a graph which is a tree, and the dominator tree of that graph. Every node's parent should be its idom, and it would of course be dominated by everything above it in the tree.