Index: llvm/trunk/include/llvm/Support/Compiler.h
===================================================================
--- llvm/trunk/include/llvm/Support/Compiler.h
+++ llvm/trunk/include/llvm/Support/Compiler.h
@@ -133,6 +133,19 @@
 #define LLVM_NODISCARD
 #endif
 
+// Indicate that a non-static, non-const C++ member function reinitializes
+// the entire object to a known state, independent of the previous state of
+// the object.
+//
+// The clang-tidy check bugprone-use-after-move recognizes this attribute as a
+// marker that a moved-from object has left the indeterminate state and can be
+// reused.
+#if __has_cpp_attribute(clang::reinitializes)
+#define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
+#else
+#define LLVM_ATTRIBUTE_REINITIALIZES
+#endif
+
 // Some compilers warn about unused functions. When a function is sometimes
 // used or not depending on build settings (e.g. a function only called from
 // within "assert"), this attribute can be used to suppress such warnings.