bug#74771: Native compilation bug with struct predicates when lexical binding enabled (HEAD)

[Eli Zaretskii]

> Cc: 74771@debbugs.gnu.org
> Date: Tue, 10 Dec 2024 22:12:03 +0000
> From:  Pip Cet via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Pip Cet <pipcet@protonmail.com> writes:
> 
> > IIUC, the code blindly assumes that cond-jump would use t as its second
> > argument.  In your code, the second argument was nil, so the assumptions
> > were put into the wrong basic blocks.
> 
> I did not understand correctly.  It seems cond-jump is still limited to
> a nil second argument, which is an undocumented assumption that comp.el
> continues to rely on.
> 
> I still think comp--emit-assume does the wrong thing when negating an
> assumption, but we've been there before...

Let's hear from Andrea (CC'ed) about this.