make things selectable

Author: Thomas Schatzl

src/hotspot/share/gc/g1/c2/g1BarrierSetC2.cpp

@@ -468,9 +468,11 @@ void G1BarrierSetC2::post_barrier(GraphKit* kit,
         Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
 
         __ if_then(card_val, BoolTest::ne, young_card, unlikely); {
-          //kit->sync_kit(ideal);
-          //kit->insert_mem_bar(Op_MemBarVolatile, oop_store);
-          //__ sync_kit(kit);
+          if (!UseNewCode) {
+            kit->sync_kit(ideal);
+            kit->insert_mem_bar(Op_MemBarVolatile, oop_store);
+            __ sync_kit(kit);
+          }
 
           Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
           __ if_then(card_val_reload, BoolTest::ne, dirty_card); {

src/hotspot/share/gc/g1/g1DirtyCardQueue.cpp

@@ -448,7 +448,11 @@ class G1RefineBufferedCards : public StackObj {
     // setting the regions' tops in humongous allocation path).
     // It's okay that reading region's top and reading region's type were racy
     // wrto each other. We need both set, in any order, to proceed.
-    SystemMemoryBarrier::emit();
+    if (!UseNewCode) {
+      OrderAccess::fence();
+    } else {
+      SystemMemoryBarrier::emit();
+    }
     sort_cards(first_clean_index);
     return refine_cleaned_cards(first_clean_index);
   }