a.cpp

#include <inttypes.h>
#include <typeinfo>
#include <stdio.h>

#define XCONCATENATE(x, y) x ## y
#define CONCATENATE(x, y) XCONCATENATE(x, y)

#define __MIN(a, b, uniq_a, uniq_b) ({ \
    const typeof(a) uniq_a = (a);      \
    const typeof(b) uniq_b = (b);      \
    uniq_a < uniq_b ? uniq_a : uniq_b; \
})
#define MIN(a, b)                              \
    __MIN((a), (b),                            \
          CONCATENATE(__uniq_a_, __COUNTER__), \
          CONCATENATE(__uniq_b_, __COUNTER__))


volatile int a = 20;

template<typename A, typename B>
static inline auto MIN1(const A &one, const B &two) -> decltype(one + two) {
    auto res = one < two ? one : two;
    return res;
}

template<typename A, typename B>
static inline auto MIN2(const A &one, const B &two) -> decltype(one + two) {
    return one < two ? one : two;
}

__attribute__((noinline)) void min()
{
    unsigned int b = 30;

    printf("%d\n", (int) MIN(a, b));
}

__attribute__((noinline)) void min1()
{
    unsigned int b = 30;

    printf("%d\n", (int) MIN1(a, b));
}

__attribute__((noinline)) void min2()
{
    unsigned int b = 30;

    printf("%d\n", (int) MIN2(a, b));
}

int main()
{
    min();
    min1();
    min2();

    return 0;
}