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From: "dberlin at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/15559] [3.3/3.4/4.0 Regression] misses opportunity for hoisting an expression that would simplify control flow
Date: Tue, 23 Nov 2004 02:53:00 -0000 [thread overview]
Message-ID: <20041123025308.21760.qmail@sourceware.org> (raw)
In-Reply-To: <20040521043035.15559.pinskia@gcc.gnu.org>
------- Additional Comments From dberlin at gcc dot gnu dot org 2004-11-23 02:53 -------
(In reply to comment #8)
> yes, but if GVNPRE hoists the operation, we end up with:
>
> int f(int i, int b, int *c)
> {
> int ii;
> ii = i+1;
> if (b)
> ;
> else
> *c = ii;
> return ii;
> }
>
> that can be later simplified to:
>
> int f(int i, int b, int *c)
> {
> int ii;
> ii = i+1;
> if (!b)
> *c = ii;
> return ii;
> }
>
This is still not faster code, only smaller code.
And you'll note that with -Os, this is what we do.
In any case, i have no plan sto make GVN-PRE do this type of hoisting, as i'm
not so interested in code size.
--
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|dberlin at gcc dot gnu dot |unassigned at gcc dot gnu
|org |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15559
next prev parent reply other threads:[~2004-11-23 2:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-22 5:38 [Bug tree-optimization/15559] New: SSAPRE misses obivous redudent expression pinskia at gcc dot gnu dot org
2004-05-22 11:49 ` [Bug tree-optimization/15559] [3.3/3.4/3.5 Regression] " giovannibajo at libero dot it
2004-05-22 11:58 ` giovannibajo at libero dot it
2004-05-22 12:06 ` pinskia at gcc dot gnu dot org
2004-05-22 13:47 ` pinskia at gcc dot gnu dot org
2004-05-22 15:27 ` [Bug tree-optimization/15559] [3.3/3.4/3.5 Regression] SSAPRE misses obvious redundant expression gdr at integrable-solutions dot net
2004-05-22 22:55 ` dberlin at gcc dot gnu dot org
2004-06-10 16:05 ` dberlin at gcc dot gnu dot org
2004-06-10 16:12 ` giovannibajo at libero dot it
2004-06-10 16:46 ` dberlin at gcc dot gnu dot org
2004-07-09 3:53 ` [Bug tree-optimization/15559] [3.3/3.4/3.5 Regression] misses opportunity for hoisting an expression that would simplify control flow pinskia at gcc dot gnu dot org
2004-11-15 2:17 ` [Bug tree-optimization/15559] [3.3/3.4/4.0 " pinskia at gcc dot gnu dot org
2004-11-15 7:53 ` steven at gcc dot gnu dot org
2004-11-23 2:49 ` dberlin at gcc dot gnu dot org
2004-11-23 2:53 ` dberlin at gcc dot gnu dot org [this message]
2004-12-12 0:06 ` steven at gcc dot gnu dot org
2005-01-21 13:46 ` steven at gcc dot gnu dot org
2005-01-21 17:13 ` mmitchel at gcc dot gnu dot org
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