Add an atomic add operation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73964 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Atomic.cpp b/lib/System/Atomic.cpp
index 416f981..6e751a3 100644
--- a/lib/System/Atomic.cpp
+++ b/lib/System/Atomic.cpp
@@ -78,4 +78,17 @@
#endif
}
+sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+#if LLVM_MULTITHREADED==0
+ *ptr += val;
+ return *ptr;
+#elif defined(__GNUC__)
+ return __sync_add_and_fetch(ptr, val);
+#elif defined(_MSC_VER)
+ return InterlockedAdd(ptr, val);
+#else
+# error No atomic add implementation for your platform!
+#endif
+}
+