#include <stdio.h>
#include <float.h>

int main(int, char**)
{
        {
        size_t match[2] = {};
        for (unsigned i = 0; i != ~0; ++i)
        {
                float a = *(float*)(&i);
                match[(1.f / a) * a == 1.f] += 1;
        }

        fprintf(stderr, "na %zu, ma %zu, ra %f\n", match[0], match[1], (double)match[0] / (match[0] + match[1]));
        }

        {
        size_t match[2] = {};
        for (float a = -1.f; a < 1.f; a += FLT_EPSILON)
        {
                match[(1.f / a) * a == 1.f] += 1;
        }

        fprintf(stderr, "na %zu, ma %zu, ra %f\n", match[0], match[1], (double)match[0] / (match[0] + match[1]));
        }
}

:!g++ -O2 check_float.cpp && ./a.out
na 692211593, ma 3602755702, ra 0.161168
na 2574161, ma 14203055, ra 0.153432

:!g++ -O2 -ffast-math check_float.cpp && ./a.out
na 682391430, ma 3612575865, ra 0.158882
na 2574160, ma 14203056, ra 0.153432