gcc/testsuite/g++.dg/cpp2a/nontype-class-union1.C

   1 // { dg-do compile { target c++20 } }
   2
   3 template <auto N> struct A {};
   4 template <class,class> struct assert_same;
   5 template <class T> struct assert_same<T,T> {};
   6
   7 #define TEQ(X,Y) static_assert(__is_same(A<(X)>,A<(Y)>))
   8 #define TNEQ(X,Y) static_assert(!__is_same(A<(X)>,A<(Y)>))
   9
  10 union U {
  11   int i; int j;
  12   constexpr U(int i): i(i) {}
  13   constexpr U(unsigned u): j(u) {}
  14 };
  15
  16 TEQ(U(0),U(0));
  17
  18 // Calling the other constructor initializes a different member with the same
  19 // value.  We need to distinguish these.
  20 TNEQ(U(0),U(0u));
  21
  22 // { dg-final { scan-assembler "_Z1f1AIXtl1Udi1iLi0EEEE" } }
  23 void f(A<U(0)>) { }
  24 // { dg-final { scan-assembler "_Z1g1AIXtl1Udi1jLi0EEEE" } }
  25 void g(A<U(0u)>) { }