https://gcc.gnu.org/bugzilla/show_bug.cgi?id=29333
--- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to rsand...@gcc.gnu.org from comment #8)
> This may be worth filing as another PR (let me know if you
> think I should), but another case of VRP stymieing phiopt is:
>
> void bar (int);
> void
> foo (int a, int b)
> {
> if (!b)
> bar (1);
> else
> {
> int c;
> if (a)
> c = a;
> else
> c = 0;
> if (c == b)
> bar (2);
> }
> }
This was testcase was fixed on trunk by a combo of patches to tree-ssa-phiopt.c
and match.pd (r12-2041, r12-2040, r12-2039, and r12-1152 [there might have been
a few more required which I missed]) which allows early phiopt to change if (a)
c = a else c = 0; to just c = a.
