bug#42147: 28.0.50; pure vs side-effect-free, missing optimizations?

[Andrea Corallo]

Mattias Engdegård <mattiase@acm.org> writes:

> More useful would be the ability to constant-fold ash, expt, %, mod and abs 
> for a subset of each respective domain. I can write a patch.

Hi Mattias,

I'm not sure what would be more useful, I guess both are a good thing to
have.  Another reason why I'm interested is that I reuse these
definitions in the native compiler.

> Andrea, I see nothing directly wrong with your patch, but perhaps our 
> messages went past one another since our lists of proposed pure functions 
> differ.

yes that exactly what happen, thanks for looking at it.

I diffed our two lists and this is the results, functions included in
mine but not in your:

consp, hash-table-p, listp, nlistp, not, null, string-lessp, stringp,
symbolp.

functions included in your but not in mine:

characterp, integer-or-marker-p, keywordp, length, number-or-marker-p,
numberp, safe-length, sequencep.

I guess for the most part I can just include the one I've missed.  I'm
not only sure about the one operating on lists like `length' given the
list may be modified in the runtime (?).

I'll update the patch once this point is clarified.

Thanks

  Andrea