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
|
#include <cstdint>
#include "benchmark/benchmark.h"
namespace {
#if defined(__GNUC__)
std::uint64_t double_up(const std::uint64_t x) __attribute__((const));
#endif
std::uint64_t double_up(const std::uint64_t x) { return x * 2; }
} // namespace
// Using DoNotOptimize on types like BitRef seem to cause a lot of problems
// with the inline assembly on both GCC and Clang.
struct BitRef {
int index;
unsigned char& byte;
public:
static BitRef Make() {
static unsigned char arr[2] = {};
BitRef b(1, arr[0]);
return b;
}
private:
BitRef(int i, unsigned char& b) : index(i), byte(b) {}
};
int main(int, char*[]) {
// this test verifies compilation of DoNotOptimize() for some types
char buffer8[8] = "";
benchmark::DoNotOptimize(buffer8);
char buffer20[20] = "";
benchmark::DoNotOptimize(buffer20);
char buffer1024[1024] = "";
benchmark::DoNotOptimize(buffer1024);
benchmark::DoNotOptimize(&buffer1024[0]);
int x = 123;
benchmark::DoNotOptimize(x);
benchmark::DoNotOptimize(&x);
benchmark::DoNotOptimize(x += 42);
benchmark::DoNotOptimize(double_up(x));
// These tests are to e
benchmark::DoNotOptimize(BitRef::Make());
BitRef lval = BitRef::Make();
benchmark::DoNotOptimize(lval);
}
|
