src/hotspot/share/c1/c1_LIRGenerator.cpp

@@ -1541,13 +1541,16 @@
 #endif
 
   if (x->needs_null_check() &&
       (needs_patching ||
        MacroAssembler::needs_explicit_null_check(x->offset()))) {
-    if (needs_patching && x->field()->is_never_null()) {
-      // We are storing a field of type "QT;", but T is not yet loaded, so we don't
-      // know whether this field is flattened or not. Let's deoptimize and recompile.
+    if (needs_patching && x->field()->is_q_type()) {
+      // We are storing a field of type "QT;" into holder class H, but H is not yet
+      // loaded. (If H had been loaded, then T must also have already been loaded
+      // due to the "Q" signature, and needs_patching would be false).
+      assert(!x->field()->holder()->is_loaded(), "must be");
+      // We don't know the offset of this field. Let's deopt and recompile.
       CodeStub* stub = new DeoptimizeStub(new CodeEmitInfo(info),
                                           Deoptimization::Reason_unloaded,
                                           Deoptimization::Action_make_not_entrant);
       __ branch(lir_cond_always, T_ILLEGAL, stub);
     } else {

@@ -1866,11 +1869,11 @@
   }
 
   return _barrier_set->resolve(this, decorators, obj);
 }
 
-Value LIRGenerator::non_nullable_load_field_prolog(LoadField* x, CodeEmitInfo* info) {
+Value LIRGenerator::q_type_load_field_prolog(LoadField* x, CodeEmitInfo* info) {
   ciField* field = x->field();
   ciInstanceKlass* holder = field->holder();
   Value default_value = NULL;
 
   // Unloaded "QV;" klasses are represented by a ciInstanceKlass

@@ -1969,12 +1972,12 @@
                   x->is_static() ?  "static" : "field", x->printable_bci());
   }
 #endif
 
   Value default_value = NULL;
-  if (x->field()->is_never_null()) {
-    default_value = non_nullable_load_field_prolog(x, info);
+  if (x->field()->is_q_type()) {
+    default_value = q_type_load_field_prolog(x, info);
   }
 
   bool stress_deopt = StressLoopInvariantCodeMotion && info && info->deoptimize_on_exception();
   if (x->needs_null_check() &&
       (needs_patching ||