[Bug other/63504] [5 Regression] Issues found by --enable-checking=valgrind

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63504

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
For 2) a short testcase is:
__uint128_t
foo (void)
{
  __uint128_t a = -1;
  __uint128_t b = a - 0x80000000ULL;
  return a / b;
}
(even on x86_64 native).