diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 0351106..0ffc0c6 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -500,8 +500,12 @@
   // C++17 features.
   if (LangOpts.CPlusPlus1z) {
     Builder.defineMacro("__cpp_hex_float", "201603");
+    Builder.defineMacro("__cpp_inline_variables", "201606");
+    //Builder.defineMacro("__cpp_aligned_new", "201606");
     //Builder.defineMacro("__cpp_noexcept_function_type", "201510");
     Builder.defineMacro("__cpp_capture_star_this", "201603");
+    Builder.defineMacro("__cpp_if_constexpr", "201606");
+    //Builder.defineMacro("__cpp_template_auto", "201606");
     Builder.defineMacro("__cpp_namespace_attributes", "201411");
     Builder.defineMacro("__cpp_enumerator_attributes", "201411");
     Builder.defineMacro("__cpp_nested_namespace_definitions", "201411");