Seems that there is an error when casting an int to a float, at least for
certain values of the integer.  The first integer to fail is 2^24... Note
also that it's only odd integer values that are a problem.
 
At least one other version (2.3.2) of gcc did not have this problem.
 
  -bash-2.05b$ gcc main_cast.c  &&  ./a.out | head
  Size of integers: 4
  Failed: 16777216.000000 != 16777217.000000
  Failed: 16777220.000000 != 16777219.000000
  Failed: 16777220.000000 != 16777221.000000
  Failed: 16777224.000000 != 16777223.000000
  Failed: 16777224.000000 != 16777225.000000
  Failed: 16777228.000000 != 16777227.000000
  Failed: 16777228.000000 != 16777229.000000
  Failed: 16777232.000000 != 16777231.000000
  Failed: 16777232.000000 != 16777233.000000
  -bash-2.05b$
 
 
--- main_cast.c ---
                                                                                
#include <stdio.h>
#include <limits.h>
                                                                                
                                                                                
int main()
{
  int i;
  float f;
                                                                                
  printf( "Size of integers: %i\n", sizeof(int) );
                                                                                
  for(  i = 0;  i < INT_MAX;  i += 1  )
  {
    f = (float)i;
    if(  f != ((float)i)  )
      printf( "Failed: %f != %f\n", f, (float)i );
  }
                                                                                
  return 0;
}