Index: polyml/libpolyml/gc_mark_phase.cpp
===================================================================
--- polyml/libpolyml/gc_mark_phase.cpp	(revision 2008)
+++ polyml/libpolyml/gc_mark_phase.cpp	(revision 2009)
@@ -176,6 +176,16 @@
     // Clear the mark stack
     for (unsigned i = 0; i < MARK_STACK_SIZE; i++)
         markStack[i] = 0;
+    // Clear the large object cache.  Actually only largeObjectCache[0].base
+    // needs to be set to zero and for the objects allocated on the heap it is
+    // cleared before each GC in either MarkRoots or MarkPointersTask.
+    // The remianing case is the RescanMarked sub-class which is allocated on the stack
+    // but it doesn't hurt to clear it in all cases.
+    for (unsigned j = 0; j < LARGECACHE_SIZE; j++)
+    {
+        largeObjectCache[locPtr].base = 0;
+        largeObjectCache[locPtr].current = 0;
+    }
 }
 
 // Called when the stack has overflowed.  We need to include this