From: Segher Boessenkool <segher@kernel.crashing.org>
To: Jiufu Guo <guojiufu@linux.ibm.com>
Cc: gcc-patches@gcc.gnu.org, rguenther@suse.de, dje.gcc@gmail.com,
jlaw@tachyum.com, wschmidt@linux.ibm.com
Subject: Re: [PATCH] Check if loading const from mem is faster
Date: Tue, 22 Feb 2022 11:30:43 -0600 [thread overview]
Message-ID: <20220222173043.GX614@gate.crashing.org> (raw)
In-Reply-To: <20220222065313.2040127-1-guojiufu@linux.ibm.com>
Hi Jiu Fu,
On Tue, Feb 22, 2022 at 02:53:13PM +0800, Jiufu Guo wrote:
> static bool
> rs6000_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
> {
> - if (GET_CODE (x) == HIGH
> - && GET_CODE (XEXP (x, 0)) == UNSPEC)
> + if (GET_CODE (x) == HIGH)
> return true;
This isn't explained anywhere. "Update" is not enough ;-)
CSE is the pass that is most ancient and still causing problems left and
right. It should be rewritten sooner rather than later.
The problem with that is that the pass does so much more than just CSE,
and we don't want to lose all those other things. So it will be a slow
arduous affair of peeling off bits into separate passes, I think :-(
Doing actual CSE without all the restrictive restrictions our pass has
historically had isn't the hard part!
Segher
next prev parent reply other threads:[~2022-02-22 17:31 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-22 6:53 Jiufu Guo
2022-02-22 7:26 ` Richard Biener
2022-02-23 11:32 ` guojiufu
2022-02-23 13:02 ` Richard Biener
2022-02-23 21:14 ` Segher Boessenkool
2022-02-24 5:56 ` Jiufu Guo
2022-02-24 6:33 ` Jiufu Guo
2022-02-24 8:50 ` Richard Biener
2022-02-25 4:35 ` Jiufu Guo
2022-02-25 8:45 ` Richard Biener
2022-02-25 13:32 ` Jiufu Guo
2022-02-25 13:57 ` Richard Biener
2022-02-28 9:15 ` Jiufu Guo
2022-02-28 17:03 ` Segher Boessenkool
2022-03-01 2:59 ` Jiufu Guo
2022-03-01 7:47 ` Richard Biener
2022-03-01 13:47 ` Jiufu Guo
2022-03-02 19:15 ` Jeff Law
2022-03-03 10:08 ` Jiufu Guo
2022-02-23 21:27 ` Segher Boessenkool
2022-02-24 7:48 ` Jiufu Guo
2022-02-28 16:45 ` Segher Boessenkool
2022-03-01 14:28 ` Jiufu Guo
2022-03-02 20:24 ` Segher Boessenkool
2022-03-03 10:09 ` Jiufu Guo
2022-03-08 11:25 ` Jiufu Guo
2022-03-08 11:50 ` Richard Biener
2022-03-09 4:37 ` Jiufu Guo
2022-03-09 7:41 ` Richard Biener
2022-03-10 2:09 ` Jiufu Guo
2022-03-10 7:09 ` Richard Biener
2022-03-11 6:33 ` Jiufu Guo
2022-02-22 17:30 ` Segher Boessenkool [this message]
2022-02-23 3:31 ` guojiufu
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=20220222173043.GX614@gate.crashing.org \
--to=segher@kernel.crashing.org \
--cc=dje.gcc@gmail.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=guojiufu@linux.ibm.com \
--cc=jlaw@tachyum.com \
--cc=rguenther@suse.de \
--cc=wschmidt@linux.ibm.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).