Index: llvm/trunk/lib/Transforms/Scalar/Sink.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/Sink.cpp
+++ llvm/trunk/lib/Transforms/Scalar/Sink.cpp
@@ -164,13 +164,14 @@
 
   // Instructions can only be sunk if all their uses are in blocks
   // dominated by one of the successors.
-  // Look at all the postdominators and see if we can sink it in one.
+  // Look at all the dominated blocks and see if we can sink it in one.
   DomTreeNode *DTN = DT.getNode(Inst->getParent());
   for (DomTreeNode::iterator I = DTN->begin(), E = DTN->end();
       I != E && SuccToSinkTo == nullptr; ++I) {
     BasicBlock *Candidate = (*I)->getBlock();
-    if ((*I)->getIDom()->getBlock() == Inst->getParent() &&
-        IsAcceptableTarget(Inst, Candidate, DT, LI))
+    // A node always immediate-dominates its children on the dominator
+    // tree.
+    if (IsAcceptableTarget(Inst, Candidate, DT, LI))
       SuccToSinkTo = Candidate;
   }