https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116865
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- if ((code == MINUS_EXPR || code == PLUS_EXPR || code == MULT_EXPR) && arg0 && arg1 && tt && POINTER_TYPE_P (tt) /* When sizetype precision doesn't match that of pointers we need to be able to build explicit extensions or truncations of the offset argument. */ && TYPE_PRECISION (sizetype) == TYPE_PRECISION (tt)) gcc_assert (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST); That means we are using a pointer type with PLUS/MINUS/MULT which is invalid AST/IR for generic . Let me try to reduce it.