diff -r 144b23411b51 -r f675976a61e7 src/share/vm/opto/loopopts.cpp
--- a/src/share/vm/opto/loopopts.cpp	Tue Nov 12 13:58:37 2013 +0100
+++ b/src/share/vm/opto/loopopts.cpp	Tue Nov 12 13:47:57 2013 +0100
@@ -42,6 +42,13 @@
     // so disable this for now
     return NULL;
   }
+
+  if (n->is_MathExact()) {
+    // MathExact has projections that are not correctly handled in the code
+    // below.
+    return NULL;
+  }
+
   int wins = 0;
   assert(!n->is_CFG(), "");
   assert(region->is_Region(), "");