https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103216
--- Comment #15 from Drea Pinski <pinskia at gcc dot gnu.org> ---
In phiopt1 we have:
```
b_3 = a_2(D) & 127;
c_4 = (signed char) b_3; // single use
d_5 = (signed char) a_2(D);
if (d_5 < 0)
goto <bb 3>; [INV]
else
goto <bb 4>; [INV]
<bb 3> :
v_7 = (signed char) a_2(D); // single use
<bb 4> :
# v_1 = PHI <c_4(2), v_7(3)>
```
So maybe I can remove the conditional definition part here. Because we can
assume sink will sink single use anyways.
