--- old/src/share/vm/gc_implementation/shared/vmGCOperations.hpp	2015-02-06 12:38:24.596166989 +0100
+++ new/src/share/vm/gc_implementation/shared/vmGCOperations.hpp	2015-02-06 12:38:24.504170185 +0100
@@ -168,7 +168,8 @@
   HeapWord* _result;    // Allocation result (NULL if allocation failed)
 
  public:
-  VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
+  VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause)
+    : VM_GC_Operation(gc_count_before, cause), _result(NULL), _word_size(word_size) {}
 
   HeapWord* result() const {
     return _result;
@@ -183,7 +184,9 @@
                              bool tlab,
                              uint gc_count_before)
     : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
-      _tlab(tlab) {}
+      _tlab(tlab) {
+    assert(word_size != 0, "An allocation should always be requested with this operation.");
+  }
   ~VM_GenCollectForAllocation()  {}
   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
   virtual void doit();