blob: 51c1a334e04e90410e1ed95efd767bb97f93e256 (
plain)
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
|
// Test for std::byte aliasing properties.
// { dg-options "-std=c++1z -O3" }
#include <cstddef>
using byte = std::byte;
enum class notbyte: unsigned char {} *np;
int main()
{
int x;
/* Stores through byte* can alias int, so the compiler can't optimize
"x != 0". */
byte *p = (byte*)&x;
x = 42;
for (int i = 0; i < 4; ++i)
p[i] = byte(0);
if (x != 0)
__builtin_abort();
/* Stores through notbyte* mustn't alias int, so at -O3 the compiler should
optimize "x != 42" to false. */
notbyte *np = (notbyte*)&x;
x = 42;
for (int i = 0; i < 4; ++i)
np[i] = notbyte(0);
if (x != 42)
__builtin_abort();
}
|