https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114523
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #7) > The problem is the verifier: > Mär 26 23:57:12 H systemd[1]: 17: (ac) w0 ^= w3 ; > R0_w=scalar() > R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1,var_off=(0x0; 0x1)) > Mär 26 23:57:12 H systemd[1]: 18: (57) r0 &= 255 ; > R0_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) > > > it lost track of what the input of r0 was. It had the right result after the > xor but then the bit_and didn't take into account the what was before it. It > just used 0xff. Or rather the verifier is keeping track of rN and rN_w seperately but GCC produces code that uses both and that definitely confuses the verifier. Mär 26 23:57:12 H systemd[1]: 16: (77) r3 >>= 63 ; R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1,var_off=(0x0; 0x1)) wait why did the verifier use r3_w here rather than just r3? that seems like the issue and would fix this issue easier ...
