--- old/src/share/vm/gc_implementation/g1/concurrentMark.cpp	2013-07-31 13:58:19.286990735 +0200
+++ new/src/share/vm/gc_implementation/g1/concurrentMark.cpp	2013-07-31 13:58:19.058990739 +0200
@@ -481,9 +481,8 @@
 
 ConcurrentMark::ConcurrentMark(G1CollectedHeap* g1h, ReservedSpace heap_rs) :
   _g1h(g1h),
-  _markBitMap1(MinObjAlignment - 1),
-  _markBitMap2(MinObjAlignment - 1),
-
+  _markBitMap1(log2_intptr(MinObjAlignment)),
+  _markBitMap2(log2_intptr(MinObjAlignment)),
   _parallel_marking_threads(0),
   _max_parallel_marking_threads(0),
   _sleep_factor(0.0),