This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/21417] Missed jump threading opportunity on trees
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 9 Feb 2006 02:36:08 -0000
- Subject: [Bug tree-optimization/21417] Missed jump threading opportunity on trees
- References: <bug-21417-280@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from law at redhat dot com 2006-02-09 02:36 -------
Subject: Re: Missed jump threading
opportunity on trees
On Mon, 2006-02-06 at 16:17 +0000, pinskia at gcc dot gnu dot org wrote:
>
> ------- Comment #3 from pinskia at gcc dot gnu dot org 2006-02-06 16:17 -------
> the load PRE issue has been fixed but DOM does not thread the jump for some
> reason.
This patch allows DOM to thread the jump in question (which in
effect pulls the conditional out of the loop, definitely a good
thing to do when we can).
As I mentioned in a previous comment, we were being very conservative
when threading across backedges in the CFG. We can be a little more
aggressive, specifically we can allow statements in the target block
which do not affect the control statement at the end of the target
block.
This triggered a few more times in my testbucket, so I'm confident
it's allowing us to avoid conditionals in at least a few real world
hunks of code.
Bootstrapped and regression tested on i686-pc-linux-gnu.
------- Comment #6 from law at redhat dot com 2006-02-09 02:36 -------
Created an attachment (id=10812)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10812&action=view)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21417