Comment by dmitrygr

  #define FIZZ 1
  #define BUZZ 2


  struct {
    uint8_t flags;
    uint8_t next;
  } static const nfo[] = {
    {FIZZ+BUZZ,1},
    {0,2},
    {0,3},
    {FIZZ,4},
    {0,5},
    {BUZZ,6},
    {FIZZ,7},
    {0,8},
    {0,9},
    {FIZZ,10},
    {BUZZ,11},
    {0,12},
    {FIZZ,13},
    {0,14},
    {0,0}
  } __attribute__((align(YOUR_L1D_LINE_SIZE)));
  static const char* strs[] = {
    [0] = "%u\n",
    [FIZZ] = "fizz\n",
    [BUZZ] = "buzz\n",
    [FIZZ+BUZZ] = "fizzbuzz\n"
  };

  void fizzbuzz(uint32_t upTo)
  {
    uint32_t i, state;

    for(i = state = 0; i < upTo; i++) {
      printf(strs[nfo[state].flags], i);
      state = nfo[state].next;
    }
  }

No divisibility tests at all. No branches besides loop and printf call. Space can be saved by using a bitfield, but masking it will add speed costs.

  .data: 0
  .rodata: 30 + 4 * sizeof(void*) + strings
  .text: depending on arch, but not much

Assuming call to printf has no cost and the caches are hot, a modern x86 cpu could execute one iteration of this loop in 1 cycle (issuing 2 loads, one add, one cmp, one branch)

I have no compiler and am typing this on a phone so please forgive typos, if any