diff --git a/src/share/vm/opto/matcher.cpp b/src/share/vm/opto/matcher.cpp
index f4097b35e75f5ec43619db29405013f3093593ea..c01785a8d61b2281fc5deff99f34b569c977f503 100644
--- a/src/share/vm/opto/matcher.cpp
+++ b/src/share/vm/opto/matcher.cpp
@@ -1657,6 +1657,7 @@ MachNode *Matcher::ReduceInst( State *s, int rule, Node *&mem ) {
 
   // Build the object to represent this state & prepare for recursive calls
   MachNode *mach = s->MachNodeGenerator( rule, C );
+  guarantee(mach != NULL, "Missing MachNode");
   mach->_opnds[0] = s->MachOperGenerator( _reduceOp[rule], C );
   assert( mach->_opnds[0] != NULL, "Missing result operand" );
   Node *leaf = s->_leaf;