--- old/src/cpu/x86/vm/c1_Runtime1_x86.cpp	2015-08-12 14:08:58.000000000 +0200
+++ new/src/cpu/x86/vm/c1_Runtime1_x86.cpp	2015-08-12 14:08:58.000000000 +0200
@@ -1774,12 +1774,17 @@
 
         NOT_LP64(__ get_thread(thread);)
 
-        __ 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);
+        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.