diff --git a/llvm/utils/TableGen/FastISelEmitter.cpp b/llvm/utils/TableGen/FastISelEmitter.cpp
index 08fc139b5d10..14d60210b314 100644
--- a/llvm/utils/TableGen/FastISelEmitter.cpp
+++ b/llvm/utils/TableGen/FastISelEmitter.cpp
@@ -287,6 +287,10 @@ void FastISelMap::CollectPatterns(CodeGenDAGPatterns &CGP) {
       if (!DstRC)
         continue;
     } else {
+      // If this isn't a leaf, then continue since the register classes are
+      // a bit too complicated for now.
+      if (!Dst->getChild(1)->isLeaf()) continue;
+      
       DefInit *SR = dynamic_cast<DefInit*>(Dst->getChild(1)->getLeafValue());
       if (SR)
         SubRegNo = getQualifiedName(SR->getDef());