--- old/src/share/vm/gc/g1/g1SATBCardTableModRefBS.cpp	2016-04-06 17:17:23.378383655 +0200
+++ new/src/share/vm/gc/g1/g1SATBCardTableModRefBS.cpp	2016-04-06 17:17:23.278383654 +0200
@@ -102,10 +102,10 @@
 }
 
 void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
-  jbyte *const first = byte_for(mr.start());
-  jbyte *const last = byte_after(mr.last());
+  volatile jbyte *const first = byte_for(mr.start());
+  volatile jbyte *const last = byte_after(mr.last());
 
-  memset_with_concurrent_readers(first, g1_young_gen, last - first);
+  memset_with_concurrent_readers((jbyte*)first, g1_young_gen, last - first);
 }
 
 #ifndef PRODUCT
@@ -143,15 +143,15 @@
   _cur_covered_regions = 1;
   _covered[0] = _whole_heap;
 
-  _byte_map = (jbyte*) mapper->reserved().start();
+  _byte_map = (volatile jbyte*) mapper->reserved().start();
   byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
   assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
   assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
 
   log_trace(gc, barrier)("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: ");
   log_trace(gc, barrier)("    &_byte_map[0]: " INTPTR_FORMAT "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
-                         p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));
-  log_trace(gc, barrier)("    byte_map_base: " INTPTR_FORMAT,  p2i(byte_map_base));
+                         p2i((jbyte*)&_byte_map[0]), p2i((jbyte*)&_byte_map[_last_valid_index]));
+  log_trace(gc, barrier)("    byte_map_base: " INTPTR_FORMAT,  p2i((jbyte*)byte_map_base));
 }
 
 void
@@ -180,7 +180,7 @@
 void
 G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) {
   volatile jbyte* byte = byte_for(mr.start());
-  jbyte* last_byte = byte_for(mr.last());
+  volatile jbyte* last_byte = byte_for(mr.last());
   Thread* thr = Thread::current();
   if (whole_heap) {
     while (byte <= last_byte) {