vendor/llvm/llvm-trunk-r303571

1 files changed, 12 insertions, 0 deletions

diff --git a/include/llvm/ADT/Statistic.h b/include/llvm/ADT/Statistic.h
index 53fa2a50fcba..d5ebba409c3d 100644
--- a/include/llvm/ADT/Statistic.h
+++ b/include/llvm/ADT/Statistic.h
@@ -101,6 +101,16 @@ public:
     return init();
   }
 
+  void updateMax(unsigned V) {
+    unsigned PrevMax = Value.load(std::memory_order_relaxed);
+    // Keep trying to update max until we succeed or another thread produces
+    // a bigger max than us.
+    while (V > PrevMax && !Value.compare_exchange_weak(
+                              PrevMax, V, std::memory_order_relaxed)) {
+    }
+    init();
+  }
+
 #else  // Statistics are disabled in release builds.
 
   const Statistic &operator=(unsigned Val) {
@@ -131,6 +141,8 @@ public:
     return *this;
   }
 
+  void updateMax(unsigned V) {}
+
 #endif  // !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
 
 protected: