diff a/src/hotspot/cpu/ppc/gc/shared/barrierSetNMethod_ppc.cpp b/src/hotspot/cpu/ppc/gc/shared/barrierSetNMethod_ppc.cpp
--- a/src/hotspot/cpu/ppc/gc/shared/barrierSetNMethod_ppc.cpp
+++ b/src/hotspot/cpu/ppc/gc/shared/barrierSetNMethod_ppc.cpp
@@ -154,10 +154,12 @@
 void BarrierSetNMethod::set_guard_value(nmethod* nm, int value, int bit_mask) {
   if (!supports_entry_barrier(nm)) {
     return;
   }
 
+  assert(nm->is_osr_method() || !nm->method()->has_scalarized_args(), "unsupported");
+
   NativeNMethodBarrier* barrier = get_nmethod_barrier(nm);
   barrier->release_set_guard_value(value, bit_mask);
 }
 
 int BarrierSetNMethod::guard_value(nmethod* nm) {