From: Andrew Haley <aph@redhat.com>
To: Tom Tromey <tromey@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: New flag: TREE_THIS_NOTRAP
Date: Tue, 15 Jun 2004 11:50:00 -0000 [thread overview]
Message-ID: <16590.52354.580748.995008@cuddles.cambridge.redhat.com> (raw)
In-Reply-To: <87brjl4sfc.fsf@fleche.redhat.com>
Tom Tromey writes:
> >>>>> "Andrew" == Andrew Haley <aph@redhat.com> writes:
>
> rth> So the NOTRAP bit is on the pointer and not the INDIRECT_REF?
>
> Andrew> It has to be doesn't it? The trapping in
> Andrew> *exp
> Andrew> is a property of exp, not a property of *.
>
> Suppose for example we have a sequence of field assignments via a
> local variable:
>
> point *var = ...;
> var->x = 1;
> var->y = 1;
>
> The first `*var' might trap, but the second one can't.
I think that's true for Java, where we're not allowed to re-order
stores.
> But in both cases wouldn't this be INDIRECT_REF<VAR_DECL> -- with the
> same argument?
Yes. But I've already been persuaded to attach the NOTRAP bit to the
INDIRECT_REF anyway. This should probably become a type attribute, so
the above could be
point *var = ...;
var->x = 1;
((notrap point*)var)->y = 1;
I'm a bit lary of generating new types, though, because I want to
avoid a memory explosion. It's perhaps worth experimenting with.
Andrew.
prev parent reply other threads:[~2004-06-15 10:17 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-09 14:03 Andrew Haley
2004-06-09 21:45 ` Richard Henderson
2004-06-09 21:46 ` Richard Henderson
2004-06-10 12:45 ` Andrew Haley
2004-06-10 18:06 ` Richard Henderson
2004-06-11 18:18 ` Andrew Haley
2004-06-11 20:37 ` Richard Henderson
2004-06-11 20:44 ` Andrew Haley
2004-06-11 20:49 ` Richard Henderson
2004-06-14 22:26 ` Jason Merrill
2004-06-16 17:17 ` Andrew Haley
2004-06-16 17:17 ` Andrew Haley
2004-06-16 17:35 ` Frank Ch. Eigler
2004-06-16 17:35 ` Andrew Haley
2004-06-16 18:30 ` Richard Henderson
2004-06-15 2:39 ` Tom Tromey
2004-06-15 11:50 ` Andrew Haley [this message]
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=16590.52354.580748.995008@cuddles.cambridge.redhat.com \
--to=aph@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=tromey@redhat.com \
/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).