From: Jakub Jelinek <jakub@redhat.com>
To: Diego Novillo <dnovillo@google.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: Fix PR 33870
Date: Thu, 08 Nov 2007 00:35:00 -0000 [thread overview]
Message-ID: <20071108003507.GQ5451@devserv.devel.redhat.com> (raw)
In-Reply-To: <b798aad50711071624q3c0ffdf0ib21f115b838a0736@mail.gmail.com>
On Wed, Nov 07, 2007 at 07:24:32PM -0500, Diego Novillo wrote:
> --- tree.h (revision 129956)
> +++ tree.h (working copy)
> @@ -2573,15 +2573,21 @@ struct tree_struct_field_tag GTY(())
> /* Size of the field. */
> unsigned HOST_WIDE_INT size;
>
> + /* True if this SFT is for a field in a nested structure. */
> + unsigned int in_nested_struct : 1;
> +
> /* Alias set for a DECL_NONADDRESSABLE_P field. Otherwise -1. */
> alias_set_type alias_set;
> };
Doesn't this grow struct tree_struct_field_tag by in most cases 8 bytes?
Aren't there enough bitfields that could be used for this bit instead?
struct tree_memory_tag GTY(())
{
struct tree_decl_minimal common;
bitmap GTY ((skip)) aliases;
unsigned int is_global:1;
};
31 or even 63 bits in tree_memory_tag (and then tree_base has a whole
bunch of spare bits, so perhaps if is_global moved to one of those too
(of course guarded with TREE_MEMORY_TAG_CHECK resp.
STRUCT_FIELD_TAG_CHECK), we would save even 8 more bytes here.
I know [tuples] does far more here, but even 4.3 will be used in the wild
and every byte in often used structs counts.
Jakub
next prev parent reply other threads:[~2007-11-08 0:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-08 0:24 Diego Novillo
2007-11-08 0:35 ` Jakub Jelinek [this message]
2007-11-08 2:20 ` Diego Novillo
2007-11-08 10:45 ` Richard Guenther
2007-11-13 16:30 ` Diego Novillo
2007-11-13 16:47 ` Richard Guenther
2007-11-14 12:36 ` Richard Guenther
2007-11-14 12:41 ` Richard Guenther
2007-11-14 13:01 ` Diego Novillo
2007-11-14 13:18 ` Richard Guenther
2007-11-14 13:59 ` Diego Novillo
2007-11-14 14:07 ` Richard Guenther
2007-11-14 14:09 ` Diego Novillo
2007-11-14 14:22 ` Richard Guenther
2007-11-14 15:29 ` Richard Guenther
2007-11-14 15:30 ` Diego Novillo
2007-11-15 13:55 ` Richard Guenther
2007-11-15 15:47 ` Richard Guenther
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20071108003507.GQ5451@devserv.devel.redhat.com \
--to=jakub@redhat.com \
--cc=dnovillo@google.com \
--cc=gcc-patches@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).