qmaster$ ./a.out
min: 7.197ms, mean: 7.839ms (607 runs, 1 loops each)

C++
#include "test.hpp"
#include <vector>
#include <random>
#include <algorithm>
#include <string>
#include "timeit.hpp"

const int Nb_Instructions = 1000000;
enum {
    OPINC, OPDEC, OPMUL2, OPDIV2, OPADD7, OPNEG
};
std::random_device rd;  //Will be used to obtain a seed for the random number engine
std::mt19937 gen(rd()); //Standard mersenne_twister_engine seeded with rd()
std::uniform_int_distribution<> distrib(OPINC, OPNEG);

Opc* genOp() {
    switch(distrib(gen)) {
        case OPINC:
            return new OpcInc();
        case OPDEC:
            return new OpcDec();
        case OPMUL2:
            return new OpcMul2();
        case OPDIV2:
            return new OpcDiv2();
        case OPADD7:
            return new OpcAdd7();
        case OPNEG:
            return new OpcNeg();
    };
}

int main(void) {
    std::vector<Opc*> vecOps;
    //vecOps.reserve(Nb_Instructions);
    for(int x = 0; x < Nb_Instructions; ++x) {
        vecOps.push_back(genOp());
    }
    
    timeit([&] {
        int result = 100;
        for(auto op: vecOps) {
            op->eval(&result);
        }}, 607
    );
}