1 // PR c++/69261
2 // { dg-do run { target c++14 } }
3
4 typedef __SIZE_TYPE__ size_t;
5
6 template <size_t N>
7 struct S
8 {
9 constexpr S() = default;
10
11 template<size_t M>
SS12 constexpr S (char const (&d)[M]) : data { 0 }
13 {
14 static_assert (M <= N, "size!");
15 for (size_t i = 0; i != M; i++)
16 data[i] = d[i];
17 }
18 char data[N];
19 };
20
21 template <int N>
22 constexpr S<N>
s(char const (& d)[N])23 s (char const (&d)[N])
24 {
25 S<N> c {};
26 for (size_t i = 0; i != N; i++)
27 c.data[i] = d[i];
28 return c;
29 }
30
31 template <size_t N, size_t M>
32 constexpr auto
concat(S<N> const & s1,S<M> const & s2)33 concat (S<N> const& s1, S<M> const& s2)
34 {
35 S<N+M-1> s (s1.data);
36 for (size_t i = 0; i != M; i++)
37 s.data[N + i - 1] = s2.data[i];
38 return s;
39 }
40
41 template <size_t N, size_t M>
42 constexpr auto
concat(char const (& x)[N],char const (& y)[M])43 concat (char const (&x)[N], char const (&y)[M])
44 {
45 S<N+M-1> tmp { x };
46 for (size_t i = 0; i != M; i++)
47 tmp.data[N+i-1] = y[i];
48 return tmp;
49 }
50
51 int
main()52 main ()
53 {
54 auto constexpr s1 = s ("bla");
55 auto constexpr s2 = s ("blub");
56 S<8> constexpr s1s2 = concat (s1, s2);
57 auto constexpr c = concat ("bla", "blub");
58 if (__builtin_strcmp (s1.data, "bla")
59 || __builtin_strcmp (s2.data, "blub")
60 || __builtin_strcmp (s1s2.data, "blablub")
61 || __builtin_strcmp (c.data, "blablub"))
62 __builtin_abort ();
63 }
64