[Bug tree-optimization/68021] [6 Regression] ice in rewrite_use_nonlinear_expr with -O3

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68021

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
void bar (void);

void
foo (int p2, int p3)
{
  unsigned long a = p2;
  unsigned long b = (~(unsigned long) ((unsigned int) p3 + -1U)) + a;
  unsigned long c = (a - (unsigned long) ((unsigned int) p3 + -1U)) + (-1UL);
  if (b != c)
    bar ();
}

shows this folding inconsistency in the *.original dump:
  long unsigned int a = (long unsigned int) p2;
  long unsigned int b = (a - (long unsigned int) ((unsigned int) p3 +
4294967295)) - 1;
  long unsigned int c = (a - (long unsigned int) ((unsigned int) p3 +
4294967295)) + 18446744073709551615;
but *.gimple already canonicalizes it, so that it does + 18446744073709551615
at the end in both cases.