[Bug rtl-optimization/97459] __uint128_t remainder for division by 3

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97459

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
And perhaps for other (but constant and not power of two) modulos use that
  unsigned long long a;
  a = (n >> 96) * (unsigned long long) (((__uint128_t 1) << 96) % c);
  a += ((n >> 64) & 0xffffffffULL) * (unsigned long long) (((__uint128_t 1) <<
64) % c);
  a += ((n >> 32) & 0xffffffffULL) * (unsigned long long) (((__uint128_t 1) <<
32) % c);
  a += (n & 0xffffffffULL);
  return a % c;
form?  Though, guess it might get quite large because the multiplications by
constants can expand again into multiple instructions.  And it needs to be
careful that the 4 addends don't overflow the 32 bits.