Feature Request: DCG Translation with Unification Spillling

[Jean-Luc-Picard-2021]

Lets say there are at least two unification spilling rewriting techniques
in a Prolog system that would eliminate a (=)/2 call:

/* Left Spilling into the Head */
p(V, Q) :- V = T, ...         ~~>            p(T, Q) :- ...

/* Right Spilling into a Goal */
..., V = T, p(V, Q), ...      ~~>            ..., p(T, Q), ... 

I find that Trealla Prolog does neither nor:

/* Trealla Prolog 2.63.33 */
p --> [a], !, [b].

?- listing(p/2).
p(A,B) :-
   A=[a|C],(!,C=D),D=[b|B].

I made a little experiment introducing both left spilling and right
spilling into a DCG translator, which previously had neither:

/* Dogelog Player 1.3.0 */
?- listing(p/2).
p([a|A], B) :-
   !,
   A = [b|B].

Now my benchmark suite DCG calculator runs 25% faster!

Source:

calc.p.log

[infradig]

If it's library/dcgs.pl at issue then i'm not messing with it.