diff --git a/src/share/vm/c1/c1_LIRGenerator.cpp b/src/share/vm/c1/c1_LIRGenerator.cpp
index abb4914fbfac567a3f2d404450e51e42cf1953d2..fcd6910ed95c894957c948a2fcde7fb896f91705 100644
--- a/src/share/vm/c1/c1_LIRGenerator.cpp
+++ b/src/share/vm/c1/c1_LIRGenerator.cpp
@@ -2232,6 +2232,7 @@ void LIRGenerator::do_UnsafeGetObject(UnsafeGetObject* x) {
       // We still need to continue with the checks.
       if (src.is_constant()) {
         ciObject* src_con = src.get_jobject_constant();
+        guarantee(src_con != NULL, "no source constant");
 
         if (src_con->is_null_object()) {
           // The constant src object is null - We can skip