Hi Jan,

Jan Nieuwenhuizen <janneke@gnu.org> writes:

> ;; foo.scm
> (let* ((set-mask (pk 'set-mask (ash 3 3)))
>        (clear-mask (pk 'clear-mask (logxor set-mask -1))))
>   (pk 'expected (logxor 24 -1))
>   (display clear-mask)
>   (newline)
>   clear-mask)
>
>
> behaves as I expect when compilation is turned off
[...]
> but when (auto)compiled, look:
[...]
> ;;; (set-mask 24)
>
> ;;; (clear-mask -1)
>
> ;;; (expected -25)
> -1

Indeed, thanks for the report.  Guile 2.2's type inference pass
contained several bugs in the range analysis of bitwise logical
operators.  I've attached below a preliminary (not fully tested) patch
that hopefully fixes these problems, and also makes some improvements.

> Is this a bug, can you suggest a workaround?

The specific workaround here would be to use (lognot x) instead of
(logxor x -1), which is a bit nicer anyway.  They are equivalent.
Another equivalent formulation is (- -1 x).

      Mark