From: Sandra Loosemore <sandra@codesourcery.com>
To: "Jeff Law" <law@redhat.com>, 瞿仙淼 <xianmiao_qu@c-sky.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
Yunhai Shang <yunhai_shang@c-sky.com>
Subject: Re: [2/5] C-SKY port: Backend implementation
Date: Fri, 03 Aug 2018 16:26:00 -0000 [thread overview]
Message-ID: <dc8d9683-01f2-432b-c1cc-28fbf1c518a5@codesourcery.com> (raw)
In-Reply-To: <1632a78d-4244-fe7b-91ae-ffdd1dd8cf60@redhat.com>
On 08/02/2018 04:27 PM, Jeff Law wrote:
> I think the cse_cc pass is really just working around one or more bugs
> in CSE and/or a backend bug. The RTL above clearly shows a common
> subexpression that is not eliminated by CSE.
>
> What CSE should be trying to do is changing the second and third
> occurrences of (gt:CC (reg 77) (reg 78)) with (reg 33) which would
> create nop-sets which would be subsequently deleted. I suspect you do
> not have an insn which matches that nop set of the CC register. If you
> fix that I suspect CSE will work better and eliminate the need for your
> cse_cc pass.
Thanks for the tip about that! I hacked things up to do as you suggest
and it appears to work. I'll post a new patch set once I've had time
for more testing, probably Monday-ish.
-Sandra
next prev parent reply other threads:[~2018-08-03 16:26 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-24 4:17 [0/5] C-SKY port Sandra Loosemore
2018-07-24 4:20 ` [1/5] C-SKY port: Configury Sandra Loosemore
2018-07-24 15:09 ` Jeff Law
2018-07-24 4:21 ` [2/5] C-SKY port: Backend implementation Sandra Loosemore
2018-07-24 15:45 ` Jeff Law
2018-07-24 18:19 ` Sandra Loosemore
2018-07-24 21:25 ` Jeff Law
2018-07-25 0:17 ` Sandra Loosemore
2018-07-25 4:50 ` Jeff Law
2018-07-25 13:17 ` Paul Koning
2018-07-25 14:54 ` Sandra Loosemore
2018-07-26 6:07 ` 瞿仙淼
2018-07-28 1:49 ` Sandra Loosemore
2018-08-02 22:33 ` Jeff Law
2018-08-02 22:28 ` Jeff Law
2018-08-03 7:58 ` Yunhai
2018-08-03 16:26 ` Sandra Loosemore [this message]
2018-07-24 4:23 ` [3/5] C-SKY port: Documentation Sandra Loosemore
2018-07-24 15:10 ` Jeff Law
2018-07-24 4:25 ` [4/5] C-SKY port: Testsuite Sandra Loosemore
2018-07-24 15:10 ` Jeff Law
2018-07-24 4:26 ` [5/5] C-SKY port: libgcc Sandra Loosemore
2018-07-24 15:12 ` Jeff Law
2018-07-24 18:10 ` Segher Boessenkool
2018-07-24 18:19 ` Sandra Loosemore
2018-07-24 19:46 ` Segher Boessenkool
2018-07-24 15:23 ` [0/5] C-SKY port Sandra Loosemore
2018-07-26 23:04 ` Joseph Myers
2018-07-30 16:59 ` Sandra Loosemore
2018-08-01 14:28 ` 瞿仙淼
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=dc8d9683-01f2-432b-c1cc-28fbf1c518a5@codesourcery.com \
--to=sandra@codesourcery.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=law@redhat.com \
--cc=xianmiao_qu@c-sky.com \
--cc=yunhai_shang@c-sky.com \
/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).