https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121695
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #3) > I see my typo: > ``` > gimple_phi_arg (phi, 0)->def = new_arg0; > gimple_phi_arg (phi, 0)->def = new_arg1; > ``` > > Should be: > ``` > gimple_phi_arg (phi, 0)->def = new_arg0; > gimple_phi_arg (phi, 1)->def = new_arg1; > ``` > > :) And yes that fixes the issue.