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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++20 -verify=expected,all %s
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++17 -verify=cxx17,all %s
// RUN: %clang_cc1 -std=c++20 -verify=ref,all %s
// RUN: %clang_cc1 -std=c++17 -verify=ref-cxx17,all %s
#define INT_MIN (~__INT_MAX__)
namespace shifts {
constexpr void test() { // ref-error {{constexpr function never produces a constant expression}} \
// ref-cxx17-error {{constexpr function never produces a constant expression}} \
// expected-error {{constexpr function never produces a constant expression}} \
// cxx17-error {{constexpr function never produces a constant expression}} \
char c; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
c = 0 << 0;
c = 0 << 1;
c = 1 << 0;
c = 1 << -0;
c = 1 >> -0;
c = 1 << -1; // expected-warning {{shift count is negative}} \
// expected-note {{negative shift count -1}} \
// cxx17-note {{negative shift count -1}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-note {{negative shift count -1}} \
// ref-cxx17-warning {{shift count is negative}} \
// ref-cxx17-note {{negative shift count -1}}
c = 1 >> -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c = 1 << (unsigned)-1; // expected-warning {{shift count >= width of type}} \
// expected-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// cxx17-warning {{shift count >= width of type}} \
// cxx17-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// ref-warning {{shift count >= width of type}} \
// ref-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}} \
// ref-cxx17-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{implicit conversion from 'int' to 'char' changes value from -2147483648 to 0}}
c = 1 >> (unsigned)-1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c = 1 << c;
c <<= 0;
c >>= 0;
c <<= 1;
c >>= 1;
c <<= -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c >>= -1; // expected-warning {{shift count is negative}} \
// cxx17-warning {{shift count is negative}} \
// ref-warning {{shift count is negative}} \
// ref-cxx17-warning {{shift count is negative}}
c <<= 999999; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= 999999; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c <<= __CHAR_BIT__; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= __CHAR_BIT__; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c <<= __CHAR_BIT__+1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
c >>= __CHAR_BIT__+1; // expected-warning {{shift count >= width of type}} \
// cxx17-warning {{shift count >= width of type}} \
// ref-warning {{shift count >= width of type}} \
// ref-cxx17-warning {{shift count >= width of type}}
(void)((long)c << __CHAR_BIT__);
int i; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
i = 1 << (__INT_WIDTH__ - 2);
i = 2 << (__INT_WIDTH__ - 1); // cxx17-warning {{bits to represent, but 'int' only has}} \
// ref-cxx17-warning {{bits to represent, but 'int' only has}}
i = 1 << (__INT_WIDTH__ - 1); // cxx17-warning-not {{sets the sign bit of the shift expression}}
i = -1 << (__INT_WIDTH__ - 1); // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
i = -1 << 0; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
i = 0 << (__INT_WIDTH__ - 1);
i = (char)1 << (__INT_WIDTH__ - 2);
unsigned u; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
u = 1U << (__INT_WIDTH__ - 1);
u = 5U << (__INT_WIDTH__ - 1);
long long int lli; // cxx17-warning {{uninitialized variable}} \
// ref-cxx17-warning {{uninitialized variable}}
lli = INT_MIN << 2; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}}
lli = 1LL << (sizeof(long long) * __CHAR_BIT__ - 2);
}
static_assert(1 << 4 == 16, "");
constexpr unsigned m = 2 >> 1;
static_assert(m == 1, "");
constexpr unsigned char c = 0 << 8;
static_assert(c == 0, "");
static_assert(true << 1, "");
static_assert(1 << (__INT_WIDTH__ +1) == 0, ""); // expected-error {{not an integral constant expression}} \
// expected-note {{>= width of type 'int'}} \
// cxx17-error {{not an integral constant expression}} \
// cxx17-note {{>= width of type 'int'}} \
// ref-error {{not an integral constant expression}} \
// ref-note {{>= width of type 'int'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{>= width of type 'int'}}
constexpr int i1 = 1 << -1; // expected-error {{must be initialized by a constant expression}} \
// expected-note {{negative shift count -1}} \
// cxx17-error {{must be initialized by a constant expression}} \
// cxx17-note {{negative shift count -1}} \
// ref-error {{must be initialized by a constant expression}} \
// ref-note {{negative shift count -1}} \
// ref-cxx17-error {{must be initialized by a constant expression}} \
// ref-cxx17-note {{negative shift count -1}}
constexpr int i2 = 1 << (__INT_WIDTH__ + 1); // expected-error {{must be initialized by a constant expression}} \
// expected-note {{>= width of type}} \
// cxx17-error {{must be initialized by a constant expression}} \
// cxx17-note {{>= width of type}} \
// ref-error {{must be initialized by a constant expression}} \
// ref-note {{>= width of type}} \
// ref-cxx17-error {{must be initialized by a constant expression}} \
// ref-cxx17-note {{>= width of type}}
constexpr char c2 = 1;
constexpr int i3 = c2 << (__CHAR_BIT__ + 1); // Not ill-formed
/// The purpose of these few lines is to test that we can shift more bits
/// than an unsigned *of the host* has. There was a bug where we casted
/// to host-unsigned. However, we cannot query what a host-unsigned even is
/// here, so only test this on platforms where `sizeof(long long) > sizeof(unsigned)`.
constexpr long long int L = 1;
constexpr signed int R = (sizeof(unsigned) * 8) + 1;
constexpr decltype(L) M = (R > 32 && R < 64) ? L << R : 0;
constexpr decltype(L) M2 = (R > 32 && R < 64) ? L >> R : 0;
constexpr int signedShift() { // cxx17-error {{never produces a constant expression}} \
// ref-cxx17-error {{never produces a constant expression}}
return 1024 << 31; // cxx17-warning {{signed shift result}} \
// ref-cxx17-warning {{signed shift result}} \
// cxx17-note {{signed left shift discards bits}} \
// ref-cxx17-note {{signed left shift discards bits}}
}
constexpr int negativeShift() { // cxx17-error {{never produces a constant expression}} \
// ref-cxx17-error {{never produces a constant expression}}
return -1 << 2; // cxx17-warning {{shifting a negative signed value is undefined}} \
// ref-cxx17-warning {{shifting a negative signed value is undefined}} \
// cxx17-note {{left shift of negative value -1}} \
// ref-cxx17-note {{left shift of negative value -1}}
}
constexpr int foo(int a) {
return -a << 2; // cxx17-note {{left shift of negative value -10}} \
// ref-cxx17-note {{left shift of negative value -10}} \
// cxx17-note {{left shift of negative value -2}} \
// ref-cxx17-note {{left shift of negative value -2}}
}
static_assert(foo(10)); // cxx17-error {{not an integral constant expression}} \
// cxx17-note {{in call to 'foo(10)'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{in call to 'foo(10)'}}
constexpr int a = -2;
static_assert(foo(a));
static_assert(foo(-a)); // cxx17-error {{not an integral constant expression}} \
// cxx17-note {{in call to 'foo(2)'}} \
// ref-cxx17-error {{not an integral constant expression}} \
// ref-cxx17-note {{in call to 'foo(2)'}}
};
namespace LongInt {
constexpr int f() {
int a = 1;
a <<= (long)0;
return 1;
}
static_assert(f() == 1, "");
};
enum shiftof {
X = (1<<-29), // all-error {{expression is not an integral constant expression}} \
// all-note {{negative shift count -29}}
X2 = (-1<<29), // cxx17-error {{expression is not an integral constant expression}} \
// cxx17-note {{left shift of negative value -1}} \
// ref-cxx17-error {{expression is not an integral constant expression}} \
// ref-cxx17-note {{left shift of negative value -1}}
X3 = (1<<32) // all-error {{expression is not an integral constant expression}} \
// all-note {{shift count 32 >= width of type 'int'}}
};
|
