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comparison gcc/testsuite/g++.dg/cpp2a/constexpr-new6.C @ 145:1830386684a0

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gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
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131:84e7813d76e9 145:1830386684a0
1 // P0784R7
2 // { dg-do compile { target c++2a } }
3
4 namespace std
5 {
6 inline namespace _8 { }
7 namespace _8 {
8
9 typedef __SIZE_TYPE__ size_t;
10
11 template <typename T>
12 struct allocator
13 {
14 constexpr allocator () noexcept {}
15
16 constexpr T *allocate (size_t n)
17 { return static_cast<T *> (::operator new (n * sizeof(T))); }
18
19 constexpr void
20 deallocate (T *p, size_t n)
21 { ::operator delete (p); }
22 };
23
24 template <typename T, typename U = T &&>
25 U __declval (int);
26 template <typename T>
27 T __declval (long);
28 template <typename T>
29 auto declval () noexcept -> decltype (__declval<T> (0));
30
31 template <typename T>
32 struct remove_reference
33 { typedef T type; };
34 template <typename T>
35 struct remove_reference<T &>
36 { typedef T type; };
37 template <typename T>
38 struct remove_reference<T &&>
39 { typedef T type; };
40
41 template <typename T>
42 constexpr T &&
43 forward (typename std::remove_reference<T>::type &t) noexcept
44 { return static_cast<T&&> (t); }
45
46 template<typename T>
47 constexpr T &&
48 forward (typename std::remove_reference<T>::type &&t) noexcept
49 { return static_cast<T&&> (t); }
50
51 template <typename T, typename... A>
52 constexpr auto
53 construct_at (T *l, A &&... a)
54 noexcept (noexcept (::new ((void *) 0) T (std::declval<A> ()...)))
55 -> decltype (::new ((void *) 0) T (std::declval<A> ()...))
56 { return ::new ((void *) l) T (std::forward<A> (a)...); }
57
58 template <typename T>
59 constexpr inline void
60 destroy_at (T *l)
61 { l->~T (); }
62 }
63 }
64
65 inline void *operator new (std::size_t, void *p) noexcept
66 { return p; }
67
68 constexpr bool
69 foo ()
70 {
71 std::allocator<int> a;
72 auto p = a.allocate (2);
73 std::construct_at (p, 1);
74 std::construct_at (p + 1, 2);
75 if (p[0] != 1 || p[1] != 2)
76 throw 1;
77 std::destroy_at (p);
78 std::destroy_at (p + 1);
79 a.deallocate (p, 2);
80 return true;
81 }
82
83 static_assert (foo ());