How to rewrite union code in glsl?

[co.der]

I have this code from C++:

float sqrt3(const float x)  
{
  union
  {
    int i;
    float x;
  } u;
  u.x = x;
  u.i = (1<<29) + (u.i >> 1) - (1<<22); 
  return u.x;
} 

I tried to write it in glsl in this manner:

float sqrt3(float x) 
{
 int i = floatBitsToInt(x)&1111;
 i = (1<<29) + (i >> 1) - (1<<22); 
 i=i&floatBitsToInt(x);
 return intBitsToFloat(i);
} 

But, I am getting a black image as output.

[GClements]

int i = floatBitsToInt(x);
i = (1<<29) + (i >> 1) - (1<<22); // = (i>>1) + 0x1fc00000
return intBitsToFloat(i);

[Alfonse_Reinheart]

@co.der

I have this code from C++:

It should be noted that this is not technically legal C++. Compilers generally will allow it, but it’s not legal according to the C++ standard, since you’re accessing a union member that is not active.

C++20 got its own “BitsTo” function in std::bit_cast, which can convert the bits of any trivially copyable object to those of another trivially copyable object of the same size.