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From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/22321] [4.0/4.1 Regression] Wrong code with SSA dominator optimizations
Date: Thu, 07 Jul 2005 07:34:00 -0000 [thread overview]
Message-ID: <20050707073417.32402.qmail@sourceware.org> (raw)
In-Reply-To: <20050706093241.22321.paul.woegerer@nsc.com>
------- Additional Comments From law at redhat dot com 2005-07-07 07:34 -------
Subject: Re: [4.0/4.1 Regression] Wrong code
with SSA dominator optimizations
On Wed, 2005-07-06 at 13:31 +0000, pinskia at gcc dot gnu dot org wrote:
> ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-07-06 13:31 -------
> This also fails too:
> volatile int x;
>
> int main ()
> {
> volatile int *vip;
> vip = &x;
> volatile int *cvip;
> cvip = vip;
>
> if (vip != cvip) return -1;
> return 0;
> }
This is actually a generic problem with fold and operand_equal_p. Given
two nodes &x and &x, operand_equal_p may return false... Which in turn
causes the conditional to be incorrectly optimized.
Jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22321
next prev parent reply other threads:[~2005-07-07 7:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-06 9:32 [Bug c++/22321] New: [4.1 " paul dot woegerer at nsc dot com
2005-07-06 9:39 ` [Bug c++/22321] " paul dot woegerer at nsc dot com
2005-07-06 9:54 ` falk at debian dot org
2005-07-06 10:55 ` paul dot woegerer at nsc dot com
2005-07-06 12:11 ` falk at debian dot org
2005-07-06 13:10 ` pinskia at gcc dot gnu dot org
2005-07-06 13:14 ` [Bug c++/22321] [4.0/4.1 " pinskia at gcc dot gnu dot org
2005-07-06 13:31 ` [Bug tree-optimization/22321] " pinskia at gcc dot gnu dot org
2005-07-06 13:38 ` paul dot woegerer at nsc dot com
2005-07-06 13:41 ` pinskia at gcc dot gnu dot org
2005-07-06 13:48 ` paul dot woegerer at nsc dot com
2005-07-06 17:04 ` mmitchel at gcc dot gnu dot org
2005-07-07 7:34 ` law at redhat dot com [this message]
2005-07-09 18:01 ` [Bug middle-end/22321] [4.0/4.1 Regression] &volatile_var != &volatile_var is always true pinskia at gcc dot gnu dot org
2005-07-09 22:59 ` law at redhat dot com
2005-07-13 17:38 ` pinskia at gcc dot gnu dot org
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