Can this piece of code be modified such that it works with fast-math enabled?

Question

Can the code below be modified such that it works correctly even when compiled by GCC with fast-math enabled?

#include <iostream>
#include <float.h>

using namespace std;

int main()
{
  char divider = 2;
  float power = 1;
  float number = 1;
  float current = number + power;
  cout.precision(20);
  // Divide until rounded off
  while(current != number)
  {
    power /= divider;
    current = number + power;
    //cout << current << endl;
  }

  cout << power * divider << endl;
  cout << FLT_EPSILON << endl;
}

Note: I have it in a header file and I haven't managed to turn off fast math for the header. See Strange while loop behavior and How to disable fast math for a header file function

Answer 1

Adding this piece of code into the loop solves the problem for me.

std::ostringstream buff;
    buff << current

Edit:

Even adding this into the condition works:

 && ! isinf(current)

Answer 2

You can turn computation in constexpr function in constant expression:

constexpr float compute_epsilon()
{
  char divider = 2;
  float power = 1;
  float number = 1;
  float current = number + power;
  // Divide until rounded off
  while(current != number)
  {
    power /= divider;
    current = number + power;
  }
  return power * divider;
}
constexpr auto epsilon = compute_epsilon();

Demo