public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/31522] [4.3 Regression] False overflow warning with phi nodes
Date: Tue, 10 Apr 2007 12:39:00 -0000 [thread overview]
Message-ID: <20070410123922.29062.qmail@sourceware.org> (raw)
In-Reply-To: <bug-31522-6528@http.gcc.gnu.org/bugzilla/>
------- Comment #4 from rguenth at gcc dot gnu dot org 2007-04-10 13:39 -------
I don't see the warning, but the range with overflow is derived from
vrp_visit_phi_node where we fall back to +INF(OVF) from [1, 536870911] because
/* To prevent infinite iterations in the algorithm, derive ranges
when the new value is slightly bigger or smaller than the
previous one. */
but why exactly do we care bout overflow infinities there at all (apart from
if the new max/min are overflowed)? Instead we throw away overflowed (and
not overflowed) infinites dropping to VARYING. Strange....
(of course the whole block preventing inifinite iterations is pessimizing
some cases which is why I introduced all_const -- we might use
all_or_all_but_one_const here ;))
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2007-04-10 13:39:22
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31522
next prev parent reply other threads:[~2007-04-10 12:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-10 7:28 [Bug tree-optimization/31522] New: [4.3 Regression] False overflow warning with division pinskia at gcc dot gnu dot org
2007-04-10 7:28 ` [Bug tree-optimization/31522] " pinskia at gcc dot gnu dot org
2007-04-10 7:30 ` pinskia at gcc dot gnu dot org
2007-04-10 7:57 ` [Bug tree-optimization/31522] [4.3 Regression] False overflow warning with division phi nodes pinskia at gcc dot gnu dot org
2007-04-10 12:39 ` rguenth at gcc dot gnu dot org [this message]
2007-04-11 5:34 ` [Bug tree-optimization/31522] False overflow warning with " pinskia at gcc dot gnu dot org
2007-04-11 6:15 ` ian at airs dot com
2007-04-11 6:38 ` pinskia at gcc dot gnu dot org
2007-04-11 7:04 ` ian at airs dot com
2007-04-11 8:14 ` rguenth at gcc dot gnu dot org
2007-04-17 5:33 ` ian at gcc dot gnu dot org
2007-04-17 18:09 ` ian at airs dot com
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=20070410123922.29062.qmail@sourceware.org \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@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).