[Bug rtl-optimization/80491] [6/7/8 Regression] Compiler regression for long-add case.

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80491

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with my r230856.  I'll have a look.
C testcase:
struct S { unsigned long long low, hi; };

struct S
add (struct S *a, struct S *b)
{
  struct S s;
  s.low = a->low + b->low;
  s.hi = a->hi + b->hi + (s.low < a->low);
  return s;
}