bug#51104: comp-tests.elc messes up after reconfiguring for different machine

[Lars Ingebrigtsen <larsi@gnus.org>]

Paul Eggert <eggert@cs.ucla.edu> writes:

> When trying out the emacs-28 branch on both 32- and 64-bit platforms,
> I had test failures that I tracked down to this line:
>
> test/src/comp-tests.el:933:       (integer ,most-negative-fixnum
> ,most-positive-fixnum))
>
> My problem was that I'd built test/src/comp-tests.elc on a 32-bit
> platform (using "./configure CC='gcc -m32'" on an x86-64 machine) so
> that .elc file had been built assuming 32-bit values for
> most-negative-fixnum and most-positive fixnum. When I then re-ran
> 'configure' for a 64-bit platform the .elc files were not
> automatically rebuilt for it (they're supposed to be
> machine-independent, right?) and so the optimizations were incorrect
> for a 64-bit platform and the tests failed.
>
> What's a good way to fix this problem, while still testing everything
> that comp-tests.el wants to test?

This was a year ago, but the code in question seems unchanged now on
"master":

      ;; 14
      ((defun comp-tests-ret-type-spec-f (x)
         (comp-hint-fixnum x))
       (integer ,most-negative-fixnum ,most-positive-fixnum))

So I guess the problem is still present?  (I haven't tested myself.)

Andrea, do you see any way to fix this test for this 32-bit/64-bit
scenarion?