https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68021
--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #11)
> 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.
associate_trees doesn't re-fold the result (due to fear of recursion I guess)
