src/cpu/x86/vm/c1_Runtime1_x86.cpp

rev 8802 : G1 performance improvements: card batching, joining, sorting, prefetching and write barrier fence elision and simplification based on a global syncrhonization using handshakes piggybacking on thread-local safepoints.
rev 8803 : Implementation improvements to pass JPRT

*** 1772,1787 ****
--- 1772,1792 ----
          __ movptr(cardtable, (intptr_t)ct->byte_map_base);
          __ addptr(card_addr, cardtable);
  
          NOT_LP64(__ get_thread(thread);)
  
+         if (G1ElideMembar) {
+           __ cmpb(Address(card_addr, 0), (int)CardTableModRefBS::clean_card_val());
+           __ jcc(Assembler::notEqual, done);
+         } else {
            __ cmpb(Address(card_addr, 0), (int)G1SATBCardTableModRefBS::g1_young_card_val());
            __ jcc(Assembler::equal, done);
  
            __ membar(Assembler::Membar_mask_bits(Assembler::StoreLoad));
            __ cmpb(Address(card_addr, 0), (int)CardTableModRefBS::dirty_card_val());
            __ jcc(Assembler::equal, done);
+         }
  
          // storing region crossing non-NULL, card is clean.
          // dirty card and log.
  
          __ movb(Address(card_addr, 0), (int)CardTableModRefBS::dirty_card_val());