clang/test/SemaTemplate/ackermann.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s
   2 // expected-no-diagnostics
   3
   4 // template<unsigned M, unsigned N>
   5 // struct Ackermann {
   6 //   enum {
   7 //     value = M ? (N ? Ackermann<M-1, Ackermann<M, N-1> >::value
   8 //                    : Ackermann<M-1, 1>::value)
   9 //               : N + 1
  10 //   };
  11 // };
  12
  13 template<unsigned M, unsigned N>
  14 struct Ackermann {
  15  enum {
  16    value = Ackermann<M-1, Ackermann<M, N-1>::value >::value
  17  };
  18 };
  19
  20 template<unsigned M> struct Ackermann<M, 0> {
  21  enum {
  22    value = Ackermann<M-1, 1>::value
  23  };
  24 };
  25
  26 template<unsigned N> struct Ackermann<0, N> {
  27  enum {
  28    value = N + 1
  29  };
  30 };
  31
  32 template<> struct Ackermann<0, 0> {
  33  enum {
  34    value = 1
  35  };
  36 };
  37
  38 int g0[Ackermann<3, 4>::value == 125 ? 1 : -1];
  39