From: Richard Stallman <rms@gnu.org>
Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org
Subject: Re: byte-code optimizations
Date: Wed, 22 Sep 2004 14:20:20 -0400 [thread overview]
Message-ID: <E1CABj2-0004St-W7@fencepost.gnu.org> (raw)
In-Reply-To: <200409212242.47848.pogonyshev@gmx.net> (message from Paul Pogonyshev on Tue, 21 Sep 2004 22:42:47 -0200)
After a `varbind' or `unwind-protect' or similar. However, I doubt
that those make much difference, so Stefan's optimization must be
_nearly_ equivalent to mine.
It would be an error to move an unbind that matches an unwind-protect.
> +(defconst byte-compile-side-effect-free-dynamically-safe-ops
> + '(;; Same as `byte-compile-side-effect-free-ops' but without
> + ;; `byte-varref', `byte-symbol-value' and certain editing
> + ;; primitives.
>
> Why exclude byte-symbol-value?
Because value can change as the result of the binding we are
trying to eliminate.
Yes, of course.
> However, there is still the question of whether we should
> change the standard defsubst to work the way defsubst* does.
Maybe we can even use `defmacro' for `caar' and friends. Since
they evaluate their lone argument only once, there must not be
any problems, right?
We don't want to replace defsubst with defmacro.
That's not what we're talking about. The idea is to
to make defsubst work better, to make it do the good things
that defsubst* does.
I vote for saying "you're not allowed to treat defsubst argument
bindings as normal dynamic bindings, and if you have tons of code
that does, well screw you, you're probably a crappy programmer
anyway."
There is no reason to consider such an unpleasant alternative.
It is clearly not necessary for making an improvement here.
Anyway, please install your updated patch.
next prev parent reply other threads:[~2004-09-22 18:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-18 13:52 byte-code optimizations Paul Pogonyshev
2004-09-18 20:26 ` Stefan
2004-09-19 11:00 ` Richard Stallman
2004-09-19 16:15 ` Paul Pogonyshev
2004-09-21 18:31 ` Richard Stallman
2004-09-22 0:42 ` Paul Pogonyshev
2004-09-21 21:05 ` Stefan Monnier
2004-09-21 21:15 ` Miles Bader
2004-09-22 3:31 ` Paul Pogonyshev
2004-09-21 22:57 ` Miles Bader
2004-09-22 3:25 ` Paul Pogonyshev
2004-09-22 18:20 ` Richard Stallman [this message]
2004-09-23 0:33 ` Paul Pogonyshev
2004-09-18 22:55 ` Richard Stallman
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