aliasing_test.cpp

#include <vector>
#include <cstdint>

using uint8_no_alias = unsigned int __attribute__((mode(QI)));


struct uint8_struct
{
    uint8_t value;
    operator const uint8_t & () const { return value; }
    operator uint8_t & () { return value; }
};


void __attribute__((__noinline__)) vector8_inc(std::vector<uint8_t>& v)
{
    for (size_t i = 0; i < v.size(); i++)
        v[i]++;
}

void __attribute__((__noinline__)) vector32_inc(std::vector<uint32_t> & v)
{
    for (size_t i = 0; i < v.size(); i++)
        v[i]++;
}

void __attribute__((__noinline__)) vector8_inc_no_alias(std::vector<uint8_no_alias> & v)
{
    for (size_t i = 0; i < v.size(); i++)
        v[i]++;
}

void __attribute__((__noinline__)) vector8_inc_struct(std::vector<uint8_struct> & v)
{
    for (size_t i = 0; i < v.size(); i++)
        v[i].value++;
}