From: Morten Welinder <terra@diku.dk>
To: gcc@gcc.gnu.org
Subject: Re: optimization/7799: [3.2/3.3 regression] Loop bug withoptimization flag -Os in gcc
Date: Fri, 13 Dec 2002 08:42:00 -0000 [thread overview]
Message-ID: <20021213162819.20923.qmail@tyr.diku.dk> (raw)
Andreas Schwab writes:
> "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de> writes:
>|> By calling fill ((int*) 0xffffffc, q);
> Undefined behaviour.
True, but its_somewhere_in_my_libc() is not. Implementation defined,
yes, but not undefined.
A quick scan of mmap's manual page suggests that it is not completely
ruled out that you would get 0xfffffffc for an area that includes
space for ten ints thereafter. (Perhaps you would have to ask for
memory starting a bit earlier, namely at the start of a page.)
With PROT_NONE this would merely be absurd behaviour, IMHO, as opposed
to certifiably insane.
Morten
next reply other threads:[~2002-12-13 16:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-13 8:42 Morten Welinder [this message]
2002-12-13 9:02 ` Andrew Pinski
2002-12-13 9:09 ` Andrew Haley
2002-12-13 10:38 ` Paul Koning
2002-12-13 13:36 Morten Welinder
2002-12-16 12:17 ` Richard Henderson
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=20021213162819.20923.qmail@tyr.diku.dk \
--to=terra@diku.dk \
--cc=gcc@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).