diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 4da7fd48fa5..c81fbaff9db 100644
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -29,10 +29,6 @@
 # define __has_attribute(x) 0
 #endif
 
-#ifndef __has_cpp_attribute
-# define __has_cpp_attribute(x) 0
-#endif
-
 #ifndef __has_builtin
 # define __has_builtin(x) 0
 #endif
@@ -405,12 +401,4 @@
 #define LLVM_THREAD_LOCAL
 #endif
 
-/// \macro LLVM_FALLTHROUGH
-/// \brief Marks an empty statement preceding a deliberate switch fallthrough.
-#if __has_cpp_attribute(clang::fallthrough)
-#define LLVM_FALLTHROUGH [[clang::fallthrough]]
-#else
-#define LLVM_FALLTHROUGH
-#endif
-
 #endif