diff -r 04b18a42c2f3 -r 69944b868a32 src/share/vm/opto/graphKit.cpp --- a/src/share/vm/opto/graphKit.cpp Fri Oct 04 13:33:02 2013 +0200 +++ b/src/share/vm/opto/graphKit.cpp Tue Oct 08 17:35:51 2013 +0200 @@ -3713,7 +3713,8 @@ Node* no_base = __ top(); float likely = PROB_LIKELY(0.999); float unlikely = PROB_UNLIKELY(0.999); - Node* zero = __ ConI(0); + Node* young_card = __ ConI((jint)G1SATBCardTableModRefBS::g1_young_card_val()); + Node* dirty_card = __ ConI((jint)CardTableModRefBS::dirty_card_val()); Node* zeroX = __ ConX(0); // Get the alias_index for raw card-mark memory @@ -3769,8 +3770,16 @@ // load the original value of the card Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw); - __ if_then(card_val, BoolTest::ne, zero); { - g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf); + __ if_then(card_val, BoolTest::ne, young_card); { + sync_kit(ideal); + // Use Op_MemBarVolatile to achieve the effect of a StoreLoad barrier. + insert_mem_bar(Op_MemBarVolatile, oop_store); + __ sync_kit(this); + + Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw); + __ if_then(card_val_reload, BoolTest::ne, dirty_card); { + g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf); + } __ end_if(); } __ end_if(); } __ end_if(); } __ end_if();