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