diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -109,6 +109,7 @@
 LANGOPT(Half              , 1, 0, "half keyword")
 LANGOPT(WChar             , 1, CPlusPlus, "wchar_t keyword")
 LANGOPT(Char8             , 1, 0, "char8_t keyword")
+LANGOPT(IEEE128           , 1, 0, "__ieee128 keyword")
 LANGOPT(DeclSpecKeyword   , 1, 0, "__declspec keyword")
 BENIGN_LANGOPT(DollarIdents   , 1, 1, "'$' in identifiers")
 BENIGN_LANGOPT(AsmPreprocessor, 1, 0, "preprocessor in asm mode")
diff --git a/clang/lib/Basic/IdentifierTable.cpp b/clang/lib/Basic/IdentifierTable.cpp
--- a/clang/lib/Basic/IdentifierTable.cpp
+++ b/clang/lib/Basic/IdentifierTable.cpp
@@ -227,6 +227,9 @@
   if (LangOpts.DeclSpecKeyword)
     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
 
+  if (LangOpts.IEEE128)
+    AddKeyword("__ieee128", tok::kw___float128, KEYALL, LangOpts, *this);
+
   // Add the 'import' contextual keyword.
   get("import").setModulesImport(true);
 }
diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -566,6 +566,7 @@
     LongDoubleFormat = Opts.PPCIEEELongDouble
                            ? &llvm::APFloat::IEEEquad()
                            : &llvm::APFloat::PPCDoubleDouble();
+  Opts.IEEE128 = 1;
 }
 
 ArrayRef<Builtin::Info> PPCTargetInfo::getTargetBuiltins() const {
diff --git a/clang/test/Sema/128bitfloat.cpp b/clang/test/Sema/128bitfloat.cpp
--- a/clang/test/Sema/128bitfloat.cpp
+++ b/clang/test/Sema/128bitfloat.cpp
@@ -6,6 +6,13 @@
 // RUN: %clang_cc1 -triple x86_64-windows-msvc -verify -std=c++11 %s
 
 #if defined(__FLOAT128__) || defined(__SIZEOF_FLOAT128__)
+
+#if defined(__ppc__)
+template <typename> struct __is_float128 { static constexpr bool value = false; };
+template <> struct __is_float128<__float128> { static constexpr bool value = true; };
+static_assert(__is_float128<__ieee128>::value, "__ieee128 aliases to __float128");
+#endif
+
 __float128 f;
 template<typename> struct __is_floating_point_helper {};
 template<> struct __is_floating_point_helper<__float128> {};