https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50832
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The assert is asserting there is only one constant operand. (eq_attr "type" "alu,alu1,negnot,imovx,ishift,ishiftx,ishift1, rotate,rotatex,rotate1,imul,icmp,push,pop") (symbol_ref "ix86_attr_length_immediate_default (insn, true)") (eq_attr "type" "imov,test") (symbol_ref "ix86_attr_length_immediate_default (insn, false)") Which I think is correct for the above types.