Mattias Engdegård [2023-02-13 10:58 -0500] wrote:

> branch: master
> commit 8aef401b4f66a64ddfa9390590fb2cae1f96d522
> Author: Mattias Engdegård <mattiase@acm.org>
> Commit: Mattias Engdegård <mattiase@acm.org>
>
>     LAP optimiser: more stack reduction hoisting
>     
>     Hoisting stack reduction ops allows them to coalesce and/or cancel out
>     pushing ops, and for useful operations to sink and combine, such as
>     not + goto-if-[not-]nil.
>     
>     * lisp/emacs-lisp/byte-opt.el (byte-optimize-lapcode):
>     Add the rule
>     
>       UNARY discardN-preserve-tos --> discardN-preserve-tos UNARY
>     
>     where UNARY pops and pushes one value.
>     
>     Generalise the rule
>     
>       const discardN-preserve-tos --> discardN const
>     
>     to any 0-ary op, not just const: varref, point, etc.

I suspect the following test is failing as a result of this
(I could bisect only to within ±1 commit):