--- old/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	2014-12-16 11:05:44.736839785 +0100
+++ new/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	2014-12-16 11:05:44.670837868 +0100
@@ -2763,7 +2763,7 @@
   default:
     ShouldNotReachHere();
   }
-  return false; // Keep some compilers happy
+  return false; // keep some compilers happy
 }
 
 HeapWord* G1CollectedHeap::top_at_mark_start(HeapRegion* hr, VerifyOption vo) {
--- old/src/share/vm/gc_implementation/g1/g1InCSetState.hpp	2014-12-16 11:05:45.137851429 +0100
+++ new/src/share/vm/gc_implementation/g1/g1InCSetState.hpp	2014-12-16 11:05:45.079849745 +0100
@@ -30,6 +30,7 @@
 
 // Per-region state during garbage collection.
 struct InCSetState {
+ private:
   // We use different types to represent the state value. Particularly SPARC puts
   // values in structs from "left to right", i.e. MSB to LSB. This results in many
   // unnecessary shift operations when loading and storing values of this type.
@@ -75,7 +76,7 @@
 
 #ifdef ASSERT
   bool is_default() const              { return is_not_in_cset(); }
-  bool is_valid() const                { return _value < Num; }
+  bool is_valid() const                { return (_value >= Humongous) && (_value < Num); }
   bool is_valid_gen() const            { return (_value >= Young && _value <= Old); }
 #endif
 };
--- old/src/share/vm/gc_implementation/g1/g1ParScanThreadState.hpp	2014-12-16 11:05:45.484861505 +0100
+++ new/src/share/vm/gc_implementation/g1/g1ParScanThreadState.hpp	2014-12-16 11:05:45.425859792 +0100
@@ -49,7 +49,7 @@
   G1ParGCAllocator* _g1_par_allocator;
 
   ageTable          _age_table;
-  InCSetState   _dest[InCSetState::Num];
+  InCSetState       _dest[InCSetState::Num];
   // Local tenuring threshold.
   uint              _tenuring_threshold;
   G1ParScanClosure  _scanner;