1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
// RUN: %clang_cc1 -std=c++2a -verify %s -fcxx-exceptions -Wno-constant-evaluated -triple=x86_64-linux-gnu
#define fold(x) (__builtin_constant_p(x) ? (x) : (x))
using size_t = decltype(sizeof(int));
namespace std {
inline constexpr bool is_constant_evaluated() noexcept {
return __builtin_is_constant_evaluated();
}
} // namespace std
extern int dummy; // expected-note 1+ {{declared here}}
static_assert(__builtin_is_constant_evaluated());
static_assert(noexcept(__builtin_is_constant_evaluated()));
constexpr bool b = __builtin_is_constant_evaluated();
static_assert(b);
const int n = __builtin_is_constant_evaluated() ? 4 : dummy;
static_assert(n == 4);
constexpr int cn = __builtin_is_constant_evaluated() ? 11 : dummy;
static_assert(cn == 11);
// expected-error@+1 {{'bn' must be initialized by a constant expression}}
constexpr int bn = __builtin_is_constant_evaluated() ? dummy : 42; // expected-note {{non-const variable 'dummy' is not allowed}}
const int n2 = __builtin_is_constant_evaluated() ? dummy : 42; // expected-note {{declared here}}
static_assert(n2 == 42); // expected-error {{static assertion expression is not an integral constant}}
// expected-note@-1 {{initializer of 'n2' is not a constant expression}}
template <bool V, bool Default = std::is_constant_evaluated()>
struct Templ { static_assert(V); static_assert(Default); };
Templ<__builtin_is_constant_evaluated()> x; // type X<true>
template <class T>
void test_if_constexpr() {
if constexpr (__builtin_is_constant_evaluated()) {
static_assert(__is_same(T, int));
} else {
using Test = typename T::DOES_NOT_EXIST;
}
}
template void test_if_constexpr<int>();
void test_array_decl() {
char x[__builtin_is_constant_evaluated() + std::is_constant_evaluated()];
static_assert(sizeof(x) == 2, "");
}
void test_case_stmt(int x) {
switch (x) {
case 0: // OK
case __builtin_is_constant_evaluated(): // expected-note {{previous case}}
case std::is_constant_evaluated() + __builtin_is_constant_evaluated(): // expected-note {{previous case}}
case 1: // expected-error {{duplicate case value '1'}}
case 2: // expected-error {{duplicate case value '2'}}
break;
}
}
constexpr size_t good_array_size() {
return std::is_constant_evaluated() ? 42 : static_cast<size_t>(-1);
}
constexpr size_t bad_array_size() {
return std::is_constant_evaluated() ? static_cast<size_t>(-1) : 13;
}
template <class T>
constexpr T require_constexpr(T v) {
if (!std::is_constant_evaluated())
throw "BOOM";
return v;
}
void test_new_expr() {
constexpr size_t TooLarge = -1;
auto *x = new int[std::is_constant_evaluated() ? 1 : TooLarge]; // expected-error {{array is too large}}
auto *x2 = new int[std::is_constant_evaluated() ? TooLarge : 1]; // OK
auto *y = new int[1][std::is_constant_evaluated() ? TooLarge : 1]{}; // expected-error {{array is too large}}
auto *y2 = new int[1][require_constexpr(42)];
}
void test_alignas_operand() {
alignas(std::is_constant_evaluated() ? 8 : 2) char dummy;
static_assert(__alignof(dummy) == 8);
}
void test_static_assert_operand() {
static_assert(std::is_constant_evaluated(), "");
}
void test_enumerator() {
enum MyEnum {
ZERO = 0,
ONE = std::is_constant_evaluated()
};
static_assert(ONE == 1, "");
}
struct TestBitfieldWidth {
unsigned Bits : std::is_constant_evaluated();
};
void test_operand_of_noexcept_fn() noexcept(std::is_constant_evaluated());
static_assert(noexcept(test_operand_of_noexcept_fn()), "");
namespace test_ref_initialization {
int x;
int y;
int &r = __builtin_is_constant_evaluated() ? x : y;
static_assert(&r == &x);
} // namespace test_ref_initialization
#if defined(__cpp_conditional_explicit)
struct TestConditionalExplicit {
explicit(!__builtin_is_constant_evaluated()) TestConditionalExplicit(int) {}
};
TestConditionalExplicit e = 42;
#endif
namespace fold_initializer {
// Global 'f' has a constant initializer.
const float f = __builtin_is_constant_evaluated();
static_assert(fold(f == 1.0f));
void g() {
// Local static 'sf' has a constant initializer.
static const float sf = __builtin_is_constant_evaluated();
static_assert(fold(sf == 1.0f));
// Local non-static 'f' has a non-constant initializer.
const float f = __builtin_is_constant_evaluated();
static_assert(fold(f == 0.0f));
}
struct A {
static const float f;
};
const float A::f = __builtin_is_constant_evaluated();
static_assert(fold(A::f == 1.0f));
}
|
