Re: mark_object crash in 22.1 and latest CVS (as of tonight)

[Richard Stallman]

    It's an "optimization" and nothing more.  In my book, if an optimization
    is unsafe, it had better make a good case for itself.  As it stands
    I see no evidence that this optimization is ever useful.  As long as
    nobody can show us numbers that demonstrate a measurable performance
    impact, I think we're better off without this optimization.

Yes, that's the crucial question.  It should be easy to get some numbers
by running an interactive application that often uses save-match-data
and compare the memory usage and amount of GC of the two versions.