From: Bernd Schmidt <bschmidt@redhat.com>
To: Segher Boessenkool <segher@kernel.crashing.org>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH 0/4] bb-reorder: Add the "simple" algorithm
Date: Thu, 24 Sep 2015 10:33:00 -0000 [thread overview]
Message-ID: <5603C8C6.9060901@redhat.com> (raw)
In-Reply-To: <cover.1443028412.git.segher@kernel.crashing.org>
On 09/24/2015 12:06 AM, Segher Boessenkool wrote:
> The current basic block reordering always uses the "software trace cache"
> algorithm. That has a few problems:
>
> 1) It increases code size substantially; this makes it not suitable for
> -O1 or -Os, and not at all for some architectures;
> 2) but it is enabled for -Os and all targets;
> 3) and -O1 gets nothing, resulting in pretty jumpy code.
A general question first, I see code in bb-reorder.c (in copy_bb_p) that
limits the amount of code growth if not optimizing for speed. Is that
not working as expected or not sufficient?
Your code looks like a nice clean algorithm so I have no objections to
it (detailed comments to follow), but I want to make sure it is
necessary to add it.
Bernd
next prev parent reply other threads:[~2015-09-24 9:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-23 22:09 Segher Boessenkool
2015-09-23 22:09 ` [PATCH 1/4] bb-reorder: Split out STC Segher Boessenkool
2015-09-24 16:12 ` Steven Bosscher
2015-09-23 22:10 ` [PATCH 2/4] bb-reorder: Add the "simple" algorithm Segher Boessenkool
2015-09-24 11:13 ` Bernd Schmidt
2015-09-24 13:48 ` Segher Boessenkool
2015-09-24 15:19 ` Segher Boessenkool
2015-09-24 16:35 ` Steven Bosscher
2015-09-24 17:22 ` Segher Boessenkool
2015-09-25 14:31 ` [PATCH 2/4 v2] " Segher Boessenkool
2015-09-25 16:09 ` Peter Bergner
2015-09-25 16:15 ` Segher Boessenkool
2015-09-29 13:19 ` Bernd Schmidt
2015-09-23 23:01 ` [PATCH 3/4] bb-reorder: Add -freorder-blocks-algorithm= and wire it up Segher Boessenkool
2015-09-24 11:00 ` Bernd Schmidt
2015-09-24 14:06 ` Segher Boessenkool
2015-09-24 15:21 ` Andi Kleen
2015-09-24 15:49 ` Segher Boessenkool
2015-09-24 17:16 ` Segher Boessenkool
[not found] ` <56377569.7010904@arm.com>
2015-11-02 15:14 ` Alan Lawrence
2015-11-02 21:04 ` Segher Boessenkool
2015-09-23 23:36 ` [PATCH 4/4] bb-reorder: Documentation updates Segher Boessenkool
2015-09-24 10:33 ` Bernd Schmidt [this message]
2015-09-24 13:32 ` [PATCH 0/4] bb-reorder: Add the "simple" algorithm Segher Boessenkool
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