Provide __GLIBCXX_TYPE_INT_N_0 and __GLIBCXX_BITSIZE_INT_N_0 when in C++ gnu language extensions.

These are used by libstdc++ <type_traits> for is_integral<__int128>. 
Addresses http://llvm.org/pr23156.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@276252 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/InitPreprocessor.cpp

@@ -961,6 +961,11 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 #include "clang/Basic/OpenCLExtensions.def"
   }
 
+  if (TI.hasInt128Type() && LangOpts.CPlusPlus && LangOpts.GNUMode) {
+    Builder.defineMacro("__GLIBCXX_TYPE_INT_N_0", "__int128");
+    Builder.defineMacro("__GLIBCXX_BITSIZE_INT_N_0", "128");
+  }
+
   // Get other target #defines.
   TI.getTargetDefines(LangOpts, Builder);
 }

test/Frontend/int128.cpp

@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -x c   -std=gnu99   -dM -E -triple x86_64-pc-linux %s | FileCheck -check-prefix=NO %s
+// RUN: %clang_cc1 -x c++ -std=c++11   -dM -E -triple x86_64-pc-linux %s | FileCheck -check-prefix=NO %s
+// RUN: %clang_cc1 -x c++ -std=gnu++11 -dM -E -triple i686-pc-linux   %s | FileCheck -check-prefix=NO %s
+// RUN: %clang_cc1 -x c++ -std=gnu++11 -dM -E -triple x86_64-pc-linux %s | FileCheck -check-prefix=YES %s
+// RUN: %clang_cc1 -x c++ -std=gnu++1y -dM -E -triple x86_64-pc-linux %s | FileCheck -check-prefix=YES %s
+// PR23156
+
+// NO-NOT: __GLIBCXX_TYPE_INT_N_0
+// NO-NOT: __GLIBCXX_BITSIZE_INT_N_0
+// YES-DAG: __GLIBCXX_TYPE_INT_N_0
+// YES-DAG: __GLIBCXX_BITSIZE_INT_N_0