From: Jeff Law <jeffreyalaw@gmail.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Andrew Pinski <apinski@marvell.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH 4/4] Improve maybe_remove_writeonly_store to do a simple DCE for defining statement
Date: Wed, 20 Oct 2021 13:53:32 -0600 [thread overview]
Message-ID: <bbf9f4f9-aa61-9d89-c997-914a99db22ab@gmail.com> (raw)
In-Reply-To: <CAFiYyc3MSz+767oyY_s84ckewtRvRkY_2Gutwjnc11a9y-+nOg@mail.gmail.com>
On 10/20/2021 12:58 AM, Richard Biener wrote:
> On Wed, Oct 20, 2021 at 1:14 AM Jeff Law via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>>
>>
>> On 10/18/2021 10:54 PM, apinski--- via Gcc-patches wrote:
>>> From: Andrew Pinski <apinski@marvell.com>
>>>
>>> Instead of putting a full blow DCE after execute_fixup_cfg, it makes sense
>>> to try to remove the defining statement for the store that is being removed.
>>> Right now we only handle PHI node statements as there needs no extra checks
>>> except for it is only used once in the store statement.
>>>
>>> gcc/ChangeLog:
>>>
>>> * tree-cfg.c (maybe_remove_writeonly_store): Remove defining
>>> (PHI) statement of the store if possible.
>> This is the only part that I consider at all controversial.
>>
>> Is the case you're trying to handle such that you have to eliminate the
>> PHI immediately and can't wait until the next DCE pass?
>>
>> If so and we want to go this direction, should we pull this out into a
>> little routine? I'm a bit surprised we don't already have one or more
>> that do basically the same thing.
> We have simple_dce_from_worklist for this which you'd seed with
> the SSA rhs of the removed stores.
Yea, that seems like a better routine to use. Andrew, can you try that?
Jeff
next prev parent reply other threads:[~2021-10-20 19:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 4:54 [PATCH 0/4] Fix PR tree-opt/102703 apinski
2021-10-19 4:54 ` [PATCH 1/4] Add dump prints when execute_fixup_cfg removes a write only var store apinski
2021-10-19 23:10 ` Jeff Law
2021-10-19 4:54 ` [PATCH 2/4] Remove outdated comment about execute_fixup_cfg apinski
2021-10-19 23:10 ` Jeff Law
2021-10-19 4:54 ` [PATCH 3/4] Factor out removal of write only stores from execute_fixup_cfg apinski
2021-10-19 23:11 ` Jeff Law
2021-10-19 4:54 ` [PATCH 4/4] Improve maybe_remove_writeonly_store to do a simple DCE for defining statement apinski
2021-10-19 23:13 ` Jeff Law
2021-10-20 6:58 ` Richard Biener
2021-10-20 19:53 ` Jeff Law [this message]
2021-10-20 19:57 ` Andrew Pinski
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=bbf9f4f9-aa61-9d89-c997-914a99db22ab@gmail.com \
--to=jeffreyalaw@gmail.com \
--cc=apinski@marvell.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=richard.guenther@gmail.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).