Is it possible to get findNearestCommonDominator working for
post dominator trees by changing llvm/include/llvm/Analysis/Dominators.h
starting at line 432:

   NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) {

     /*assert (!this->isPostDominator()
&& "This is not implemented for post dominators");*/
     assert (A->getParent() == B->getParent()
&& "Two blocks are not in same function");

if (!this->isPostDominator())
     // If either A or B is a entry block then it is nearest common dominator.
     NodeT &Entry = A->getParent()->front();
     if (A == &Entry || B == &Entry)
       return &Entry;

     // If B dominates A then B is nearest common dominator.
     if (dominates(B, A))
       return B;


- Jochen

That looks right to me. I committed it as r99361.