diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index 24e0277..12337c9 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -143,7 +143,7 @@
  protected:
   CodeGenerator(HGraph* graph, size_t number_of_registers)
       : frame_size_(kUninitializedFrameSize),
-        core_spill_mask_(-1),
+        core_spill_mask_(0),
         graph_(graph),
         block_labels_(graph->GetArena(), 0),
         pc_infos_(graph->GetArena(), 32),