--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/PCH/cxx1y-variable-templates.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,171 @@
+// No PCH:
+// RUN: %clang_cc1 -pedantic -std=c++1y -include %s -include %s -verify %s -DNONPCH
+// RUN: %clang_cc1 -pedantic -std=c++1y -include %s -include %s -verify %s -DNONPCH -DERROR
+//
+// With PCH:
+// RUN: %clang_cc1 -pedantic -std=c++1y -emit-pch %s -o %t.a -DHEADER1
+// RUN: %clang_cc1 -pedantic -std=c++1y -include-pch %t.a -emit-pch %s -o %t.b -DHEADER2
+// RUN: %clang_cc1 -pedantic -std=c++1y -include-pch %t.b -verify %s -DHEADERUSE
+
+#ifndef ERROR
+// expected-no-diagnostics
+#endif
+
+#ifdef NONPCH
+#if !defined(HEADER1)
+#define HEADER1
+#undef HEADER2
+#undef HEADERUSE
+#elif !defined(HEADER2)
+#define HEADER2
+#undef HEADERUSE
+#else
+#define HEADERUSE
+#undef HEADER1
+#undef HEADER2
+#endif
+#endif
+
+
+// *** HEADER1: First header file
+#if defined(HEADER1) && !defined(HEADER2) && !defined(HEADERUSE)
+
+template<typename T> T var0a = T();
+template<typename T> extern T var0b;
+
+namespace join {
+  template<typename T> T va = T(100);
+  template<typename T> extern T vb;
+
+  namespace diff_types {
+#ifdef ERROR
+    template<typename T> extern float err0;
+    template<typename T> extern T err1;
+#endif
+    template<typename T> extern T def;
+  }
+
+}
+
+namespace spec {
+  template<typename T> constexpr T va = T(10);
+  template<> constexpr float va<float> = 1.5;
+  template constexpr int va<int>;
+
+  template<typename T> T vb = T();
+  template<> constexpr float vb<float> = 1.5;
+
+  template<typename T> T vc = T();
+
+  template<typename T> constexpr T vd = T(10);
+  template<typename T> T* vd<T*> = new T();
+}
+
+namespace spec_join1 {
+  template<typename T> T va = T(10);
+  template<> extern float va<float>;
+  extern template int va<int>;
+
+  template<typename T> T vb = T(10);
+  template<> extern float vb<float>;
+
+  template<typename T> T vc = T(10);
+
+  template<typename T> T vd = T(10);
+  template<typename T> extern T* vd<T*>;
+}
+
+#endif
+
+
+// *** HEADER2: Second header file -- including HEADER1
+#if defined(HEADER2) && !defined(HEADERUSE)
+
+namespace join {
+  template<typename T> extern T va;
+  template<> constexpr float va<float> = 2.5;
+
+  template<typename T> T vb = T(100);
+
+  namespace diff_types {
+#ifdef ERROR
+    template<typename T> extern T err0; // expected-error {{redeclaration of 'err0' with a different type: 'T' vs 'float'}}  // expected-note@42 {{previous declaration is here}}
+    template<typename T> extern float err1; // expected-error {{redeclaration of 'err1' with a different type: 'float' vs 'T'}} // expected-note@43 {{previous declaration is here}}
+#endif
+    template<typename T> extern T def;
+  }
+}
+
+namespace spec_join1 {
+  template<typename T> extern T va;
+  template<> float va<float> = 1.5;
+  extern template int va<int>;
+  
+  template<> float vb<float> = 1.5;
+  template int vb<int>;
+
+  template<> float vc<float> = 1.5;
+  template int vc<int>;
+  
+  template<typename T> extern T vd;
+  template<typename T> T* vd<T*> = new T();
+}
+
+#endif
+
+// *** HEADERUSE: File using both header files -- including HEADER2
+#ifdef HEADERUSE
+
+template int var0a<int>;
+float fvara = var0a<float>;
+
+template<typename T> extern T var0a; 
+
+template<typename T> T var0b = T(); 
+template int var0b<int>;
+float fvarb = var0b<float>;
+
+namespace join {
+  template const int va<const int>;
+  template<> const int va<int> = 50;
+  static_assert(va<float> == 2.5, "");
+  static_assert(va<int> == 50, "");
+
+  template<> constexpr float vb<float> = 2.5;
+  template const int vb<const int>;
+  static_assert(vb<float> == 2.5, "");
+  static_assert(vb<const int> == 100, "");
+
+  namespace diff_types {
+    template<typename T> T def = T();
+  }
+
+}
+
+namespace spec {
+  static_assert(va<float> == 1.5, "");
+  static_assert(va<int> == 10, "");
+
+  template<typename T> T* vb<T*> = new T();
+  int* intpb = vb<int*>;
+  static_assert(vb<float> == 1.5, "");
+
+  template<typename T> T* vc<T*> = new T();
+  template<> constexpr float vc<float> = 1.5;
+  int* intpc = vc<int*>;
+  static_assert(vc<float> == 1.5, "");
+
+  char* intpd = vd<char*>;
+}
+
+namespace spec_join1 {
+  template int va<int>;
+  int a = va<int>;
+
+  template<typename T> extern T vb;
+  int b = vb<int>;
+
+  int* intpb = vd<int*>;
+}
+
+#endif