Several improvements to template argument deduction:

  - Once we have deduced template arguments for a class template partial
    specialization, we use exactly those template arguments for instantiating
    the definition of the class template partial specialization.
  - Added template argument deduction for non-type template parameters.
  - Added template argument deduction for dependently-sized array types.

With these changes, we can now implement, e.g., the remove_reference
type trait. Also, Daniel's Ackermann template metaprogram now compiles
properly.

llvm-svn: 72909

2 files changed, 60 insertions, 0 deletions

diff --git a/clang/test/SemaTemplate/ackermann.cpp b/clang/test/SemaTemplate/ackermann.cpp
new file mode 100644
index 00000000000..48fbbbb3cf1
--- /dev/null
+++ b/clang/test/SemaTemplate/ackermann.cpp
@@ -0,0 +1,37 @@
+// RUN: clang-cc -fsyntax-only -ftemplate-depth=1000 -verify %s
+
+// template<unsigned M, unsigned N>
+// struct Ackermann {
+//   enum {
+//     value = M ? (N ? Ackermann<M-1, Ackermann<M-1, N-1> >::value
+//                    : Ackermann<M-1, 1>::value)
+//               : N + 1
+//   };
+// };
+
+template<unsigned M, unsigned N>
+struct Ackermann {
+ enum {
+   value = Ackermann<M-1, Ackermann<M, N-1>::value >::value
+ };
+};
+
+template<unsigned M> struct Ackermann<M, 0> {
+ enum {
+   value = Ackermann<M-1, 1>::value
+ };
+};
+
+template<unsigned N> struct Ackermann<0, N> {
+ enum {
+   value = N + 1
+ };
+};
+
+template<> struct Ackermann<0, 0> {
+ enum {
+   value = 1
+ };
+};
+
+int g0[Ackermann<3, 8>::value == 2045 ? 1 : -1];
diff --git a/clang/test/SemaTemplate/temp_class_spec.cpp b/clang/test/SemaTemplate/temp_class_spec.cpp
index d516f01d7fd..8cb46cf98f8 100644
--- a/clang/test/SemaTemplate/temp_class_spec.cpp
+++ b/clang/test/SemaTemplate/temp_class_spec.cpp
@@ -51,6 +51,19 @@ int is_same2[is_same<const int, int>::value? -1 : 1];
 int is_same3[is_same<int_ptr, int>::value? -1 : 1];
 
 template<typename T>
+struct remove_reference {
+  typedef T type;
+};
+
+template<typename T>
+struct remove_reference<T&> {
+  typedef T type;
+};
+
+int remove_ref0[is_same<remove_reference<int>::type, int>::value? 1 : -1];
+int remove_ref1[is_same<remove_reference<int&>::type, int>::value? 1 : -1];
+                
+template<typename T>
 struct is_incomplete_array {
   static const bool value = false;
 };
@@ -79,3 +92,13 @@ int array_with_4_elements0[is_array_with_4_elements<int[]>::value ? -1 : 1];
 int array_with_4_elements1[is_array_with_4_elements<int[1]>::value ? -1 : 1];
 int array_with_4_elements2[is_array_with_4_elements<int[4]>::value ? 1 : -1];
 int array_with_4_elements3[is_array_with_4_elements<int[4][2]>::value ? 1 : -1];
+
+template<typename T>
+struct get_array_size;
+
+template<typename T, unsigned N>
+struct get_array_size<T[N]> {
+  static const unsigned value = N;
+};
+
+int array_size0[get_array_size<int[12]>::value == 12? 1 : -1];