https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112706
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #1) > That is: > ``` > (for op (eq ne) > (simplify > (op (pointer_plus @0 @1) (pointer_plus @0 @2)) > (op @1 @2)) > > ``` Note I am missing a extra `)` but then I Noticed in the full testcase (that is located in https://gcc.gnu.org/pipermail/gcc-patches/2023-November/638130.html) which was originally reported we still end up with: ``` _76 = _71 + 4; # .MEM_154 = VDEF <.MEM_153> x_3(D)->D.25942._M_implD.25172.D.25249._M_finishD.25175 = _76; # .MEM_7 = VDEF <.MEM_154> D.26033 = 0; # .MEM_157 = VDEF <.MEM_7> *_76 = 0; # PT = nonlocal escaped _82 = _71 + 8; # .MEM_158 = VDEF <.MEM_157> x_3(D)->D.25942._M_implD.25172.D.25249._M_finishD.25175 = _82; # .MEM_8 = VDEF <.MEM_158> D.26033 ={v} {CLOBBER(eol)}; # .MEM_9 = VDEF <.MEM_8> D.26034 = 0; if (_66 != _82) ``` After pre (note the first comparison is gone but not the second one and maybe a 3rd). So this patch helps but it looks like a PRE/VN improvement is still needed to fix the others.
