message: Rename `unsigned_offset_from` to `sub_ptr`
diff: @@ -721,7 +721,7 @@ fn swap(bcx: &mut FunctionBuilder<'_>, v: Value) -> Value {
  let diff_bytes = fx.bcx.ins().isub(ptr, base);
  // FIXME this can be an exact division.
  let diff = if intrinsic == sym::ptr_offset_from_unsigned {
  - // Because diff_bytes ULT isize::MAX, this would be fine as signed,
  + // Because diff_bytes ULE isize::MAX, this would be fine as signed,
  // but unsigned is slightly easier to codegen, so might as well.
  fx.bcx.ins().udiv_imm(diff_bytes, pointee_size as i64)
  } else {
  