diff --git a/bolt/include/bolt/Passes/ShrinkWrapping.h b/bolt/include/bolt/Passes/ShrinkWrapping.h
--- a/bolt/include/bolt/Passes/ShrinkWrapping.h
+++ b/bolt/include/bolt/Passes/ShrinkWrapping.h
@@ -308,8 +308,8 @@
   std::vector<MCInst *> BestSavePos;
 
   /// Pass stats
-  static uint64_t SpillsMovedRegularMode;
-  static uint64_t SpillsMovedPushPopMode;
+  static std::atomic_uint64_t SpillsMovedRegularMode;
+  static std::atomic_uint64_t SpillsMovedPushPopMode;
 
   Optional<unsigned> AnnotationIndex;
 
diff --git a/bolt/lib/Passes/ShrinkWrapping.cpp b/bolt/lib/Passes/ShrinkWrapping.cpp
--- a/bolt/lib/Passes/ShrinkWrapping.cpp
+++ b/bolt/lib/Passes/ShrinkWrapping.cpp
@@ -710,8 +710,8 @@
   IsInitialized = true;
 }
 
-uint64_t ShrinkWrapping::SpillsMovedRegularMode = 0;
-uint64_t ShrinkWrapping::SpillsMovedPushPopMode = 0;
+std::atomic_uint64_t ShrinkWrapping::SpillsMovedRegularMode{0};
+std::atomic_uint64_t ShrinkWrapping::SpillsMovedPushPopMode{0};
 
 using BBIterTy = BinaryBasicBlock::iterator;