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From: Paul Eggert <eggert@cs.ucla.edu>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 65491@debbugs.gnu.org, mattias.engdegard@gmail.com,
	monnier@iro.umontreal.ca
Subject: bug#65491: [PATCH] Improve performance allocating vectors
Date: Sun, 17 Sep 2023 08:22:01 -0700	[thread overview]
Message-ID: <a5dd6c16-ebc4-7970-3d94-365766beae72@cs.ucla.edu> (raw)
In-Reply-To: <83led5gyxa.fsf@gnu.org>

On 2023-09-16 22:18, Eli Zaretskii wrote:

> It seems to me that in a 32-bit build with wide
> ints just
> 
>    #define XUNTAG(a, type, ctype) ((ctype *) XLP (a))
> 
> should be enough, since XLP yields a 'void *', no?

That would complicate the code unnecessarily. Let's not go there. Patch 
P works as-is, and it's simpler. Let's do that instead.


> what I
> meant was to have a separate definition of XUNTAG for 32-bit builds
> with wide ints (which could still remove the undefined behavior),

Yes, that's exactly what I suggest not to do. Why complicate the source 
code unnecessarily? And if we complicate it here, why not complicate it 
in similar ways in dozens of other places?

I went through a lot of this when adding support for --with-wide-int in 
the first place, years ago. When doing so, I strove to avoid having 
multiple copies of the code whenever I could. And I pretty much 
succeeded: there are only two WITH_WIDE_INT conditionals in lisp.h (and 
only three in other source files, all introduced relatively recently by 
others to work around compiler bugs, and all which should be rewritten 
without the #if).

It's an obvious win to have just one copy of the code instead of two, 
when one copy works and is just as efficient.  As much as possible, 
--with-wide-int should not be a special case.  We should not have 
"#ifdef WITH_WIDE_INT" scattered all over the place.  Keep it simple.






  reply	other threads:[~2023-09-17 15:22 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-24  9:59 bug#65491: [PATCH] Improve performance allocating vectors Ihor Radchenko
2023-08-26  7:14 ` Eli Zaretskii
2023-08-26  7:27   ` Ihor Radchenko
2023-08-26  7:31     ` Eli Zaretskii
2023-08-26  7:51       ` Ihor Radchenko
2023-08-26  8:07         ` Ihor Radchenko
2023-08-26  9:01         ` Eli Zaretskii
2023-08-26  7:47     ` Ihor Radchenko
2023-08-26 12:01 ` Mattias Engdegård
2023-08-26 14:54   ` Ihor Radchenko
2023-08-26 14:55   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-27  9:54     ` Mattias Engdegård
2023-09-16 14:58     ` Mattias Engdegård
2023-09-16 16:12       ` Eli Zaretskii
2023-09-16 16:17         ` Eli Zaretskii
2023-09-16 16:32           ` Mattias Engdegård
2023-09-16 16:54             ` Eli Zaretskii
2023-09-16 17:03               ` Mattias Engdegård
2023-09-16 17:11                 ` Eli Zaretskii
2023-09-17  3:02                 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-17 17:02                   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-18  2:19                     ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-18  2:27                       ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-18  3:08                         ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-18  4:10                           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-09-16 16:54             ` Mattias Engdegård
2023-09-16 17:09               ` Eli Zaretskii
2023-09-16 17:22                 ` Mattias Engdegård
2023-09-16 18:19                   ` Eli Zaretskii
2023-09-16 19:04                     ` Mattias Engdegård
2023-09-16 19:46                 ` Paul Eggert
2023-09-17  5:18                   ` Eli Zaretskii
2023-09-17 15:22                     ` Paul Eggert [this message]
2023-09-17 16:15                       ` Eli Zaretskii
2023-09-17 16:37                         ` Paul Eggert
2023-09-17 16:44                           ` Eli Zaretskii
2023-09-18 16:10                             ` Mattias Engdegård
2023-09-18 17:13                               ` Eli Zaretskii
2023-09-19 13:28                               ` Mattias Engdegård
2023-09-19 14:04                                 ` Eli Zaretskii
2023-09-19 14:05                                   ` Mattias Engdegård
2023-09-25 16:06       ` Mattias Engdegård
2023-08-27 16:21 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-28 10:14   ` Ihor Radchenko
2023-08-28 16:32     ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-28 12:47   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors

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