--- a/hotspot/src/share/vm/jvmci/jvmciCompilerToVM.cpp	Wed Jun 22 21:13:52 2016 +0000
+++ b/hotspot/src/share/vm/jvmci/jvmciCompilerToVM.cpp	Wed Jun 22 22:39:32 2016 +0000
@@ -113,6 +113,7 @@
 bool       CompilerToVM::Data::_supports_inline_contig_alloc;
 HeapWord** CompilerToVM::Data::_heap_end_addr;
 HeapWord** CompilerToVM::Data::_heap_top_addr;
+int CompilerToVM::Data::_max_oop_map_stack_offset;
 
 jbyte* CompilerToVM::Data::cardtable_start_address;
 int CompilerToVM::Data::cardtable_shift;
@@ -154,6 +155,11 @@
   _heap_end_addr = _supports_inline_contig_alloc ? Universe::heap()->end_addr() : (HeapWord**) -1;
   _heap_top_addr = _supports_inline_contig_alloc ? Universe::heap()->top_addr() : (HeapWord**) -1;
 
+  _max_oop_map_stack_offset = (OopMapValue::register_mask - VMRegImpl::stack2reg(0)->value()) * VMRegImpl::stack_slot_size;
+  int max_oop_map_stack_index = _max_oop_map_stack_offset / VMRegImpl::stack_slot_size;
+  assert(OopMapValue::legal_vm_reg_name(VMRegImpl::stack2reg(max_oop_map_stack_index)), "should be valid");
+  assert(!OopMapValue::legal_vm_reg_name(VMRegImpl::stack2reg(max_oop_map_stack_index + 1)), "should be invalid");
+
   BarrierSet* bs = Universe::heap()->barrier_set();
   switch (bs->kind()) {
   case BarrierSet::CardTableModRef: