1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // <numeric>
10
11 // Became constexpr in C++20
12 // template <InputIterator Iter, MoveConstructible T,
13 // Callable<auto, const T&, Iter::reference> BinaryOperation>
14 // requires HasAssign<T, BinaryOperation::result_type>
15 // && CopyConstructible<BinaryOperation>
16 // T
17 // accumulate(Iter first, Iter last, T init, BinaryOperation binary_op);
18
19 #include <numeric>
20 #include <functional>
21 #include <string>
22 #include <cassert>
23
24 #include "test_macros.h"
25 #include "test_iterators.h"
26
27 #if TEST_STD_VER > 17
28 struct rvalue_addable
29 {
30 bool correctOperatorUsed = false;
31
32 // make sure the predicate is passed an rvalue and an lvalue (so check that the first argument was moved)
operator ()rvalue_addable33 constexpr rvalue_addable operator()(rvalue_addable&& r, rvalue_addable const&) {
34 r.correctOperatorUsed = true;
35 return std::move(r);
36 }
37 };
38
operator +(rvalue_addable & lhs,rvalue_addable const &)39 constexpr rvalue_addable operator+(rvalue_addable& lhs, rvalue_addable const&)
40 {
41 lhs.correctOperatorUsed = false;
42 return lhs;
43 }
44
operator +(rvalue_addable && lhs,rvalue_addable const &)45 constexpr rvalue_addable operator+(rvalue_addable&& lhs, rvalue_addable const&)
46 {
47 lhs.correctOperatorUsed = true;
48 return std::move(lhs);
49 }
50
51 constexpr void
test_use_move()52 test_use_move()
53 {
54 rvalue_addable arr[100];
55 auto res1 = std::accumulate(arr, arr + 100, rvalue_addable());
56 auto res2 = std::accumulate(arr, arr + 100, rvalue_addable(), /*predicate=*/rvalue_addable());
57 assert(res1.correctOperatorUsed);
58 assert(res2.correctOperatorUsed);
59 }
60 #endif // TEST_STD_VER > 17
61
62 // C++20 can use string in constexpr evaluation, but both libc++ and MSVC
63 // don't have the support yet. In these cases omit the constexpr test.
64 // FIXME Remove constexpr string workaround introduced in D90569
65 #if TEST_STD_VER > 17 && \
66 (!defined(__cpp_lib_constexpr_string) || __cpp_lib_constexpr_string < 201907L)
67 void
68 #else
69 TEST_CONSTEXPR_CXX20 void
70 #endif
test_string()71 test_string()
72 {
73 std::string sa[] = {"a", "b", "c"};
74 assert(std::accumulate(sa, sa + 3, std::string()) == "abc");
75 assert(std::accumulate(sa, sa + 3, std::string(), std::plus<std::string>()) == "abc");
76 }
77
78 template <class Iter, class T>
79 TEST_CONSTEXPR_CXX20 void
test(Iter first,Iter last,T init,T x)80 test(Iter first, Iter last, T init, T x)
81 {
82 assert(std::accumulate(first, last, init, std::multiplies<T>()) == x);
83 }
84
85 template <class Iter>
86 TEST_CONSTEXPR_CXX20 void
test()87 test()
88 {
89 int ia[] = {1, 2, 3, 4, 5, 6};
90 unsigned sa = sizeof(ia) / sizeof(ia[0]);
91 test(Iter(ia), Iter(ia), 1, 1);
92 test(Iter(ia), Iter(ia), 10, 10);
93 test(Iter(ia), Iter(ia+1), 1, 1);
94 test(Iter(ia), Iter(ia+1), 10, 10);
95 test(Iter(ia), Iter(ia+2), 1, 2);
96 test(Iter(ia), Iter(ia+2), 10, 20);
97 test(Iter(ia), Iter(ia+sa), 1, 720);
98 test(Iter(ia), Iter(ia+sa), 10, 7200);
99 }
100
101 TEST_CONSTEXPR_CXX20 bool
test()102 test()
103 {
104 test<cpp17_input_iterator<const int*> >();
105 test<forward_iterator<const int*> >();
106 test<bidirectional_iterator<const int*> >();
107 test<random_access_iterator<const int*> >();
108 test<const int*>();
109
110 #if TEST_STD_VER > 17
111 test_use_move();
112 #endif // TEST_STD_VER > 17
113 // C++20 can use string in constexpr evaluation, but both libc++ and MSVC
114 // don't have the support yet. In these cases omit the constexpr test.
115 // FIXME Remove constexpr string workaround introduced in D90569
116 #if TEST_STD_VER > 17 && \
117 (!defined(__cpp_lib_constexpr_string) || __cpp_lib_constexpr_string < 201907L)
118 if (!std::is_constant_evaluated())
119 #endif
120 test_string();
121
122 return true;
123 }
124
main(int,char **)125 int main(int, char**)
126 {
127 test();
128 #if TEST_STD_VER > 17
129 static_assert(test());
130 #endif
131 return 0;
132 }
133