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 #include <assert.h>
10 #include <cmath>
11 #include <cstdint>
12 #include <limits>
13 #include <type_traits>
14 
15 #include "test_macros.h"
16 
17 template<class T>
18 struct correct_size_int
19 {
20     typedef typename std::conditional<sizeof(T) < sizeof(int), int, T>::type type;
21 };
22 
23 template <class Source, class Result>
24 void test_abs()
25 {
26     Source neg_val = -5;
27     Source pos_val = 5;
28     Result res = 5;
29 
30     ASSERT_SAME_TYPE(decltype(std::abs(neg_val)), Result);
31 
32     assert(std::abs(neg_val) == res);
33     assert(std::abs(pos_val) == res);
34 }
35 
36 void test_big()
37 {
38     long long int big_value = std::numeric_limits<long long int>::max(); // a value too big for ints to store
39     long long int negative_big_value = -big_value;
40     assert(std::abs(negative_big_value) == big_value); // make sure it doesn't get casted to a smaller type
41 }
42 
43 // The following is helpful to keep in mind:
44 // 1byte == char <= short <= int <= long <= long long
45 
46 int main(int, char**)
47 {
48     // On some systems char is unsigned.
49     // If that is the case, we should just test signed char twice.
50     typedef std::conditional<
51         std::is_signed<char>::value, char, signed char
52     >::type SignedChar;
53 
54     // All types less than or equal to and not greater than int are promoted to int.
55     test_abs<short int, int>();
56     test_abs<SignedChar, int>();
57     test_abs<signed char, int>();
58 
59     // These three calls have specific overloads:
60     test_abs<int, int>();
61     test_abs<long int, long int>();
62     test_abs<long long int, long long int>();
63 
64     // Here there is no guarantee that int is larger than int8_t so we
65     // use a helper type trait to conditional test against int.
66     test_abs<std::int8_t, correct_size_int<std::int8_t>::type>();
67     test_abs<std::int16_t, correct_size_int<std::int16_t>::type>();
68     test_abs<std::int32_t, correct_size_int<std::int32_t>::type>();
69     test_abs<std::int64_t, correct_size_int<std::int64_t>::type>();
70 
71     test_abs<long double, long double>();
72     test_abs<double, double>();
73     test_abs<float, float>();
74 
75     test_big();
76 
77     return 0;
78 }
79