[Bug rtl-optimization/81423] [6/7 Regression] Wrong code at -O2

[babokin at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81423

--- Comment #16 from Dmitry Babokin <babokin at gmail dot com> ---
ll = -5597998501375493990LL;

// result is 2595916314 here.
ll = unsigned(5677365550390624949L - ll) - (ull1 > 0);

So:
  // t1 is 466811183
  unsigned long long int t1 = ll + -2129105131L;
  // t2 is 10280750143997242019
  unsigned long long int t2 = t1 ^ 10280750144413668236ULL;
  // t3 is 10
  unsigned long long int t3 = t2 - 10280750143997242009ULL;

So the test case looks correct to me.

UBSAN also doesn't complain.