From: Luis Machado <luis.machado@linaro.org>
To: Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>, gcc-patches@gcc.gnu.org
Cc: james.greenhalgh@arm.com, Richard.Earnshaw@arm.com
Subject: Re: [PATCH, v2] Recognize a missed usage of a sbfiz instruction
Date: Mon, 07 May 2018 14:28:00 -0000 [thread overview]
Message-ID: <d3889cba-56a3-6709-579f-d5384d75050c@linaro.org> (raw)
In-Reply-To: <d756d9f7-416f-33fe-2dad-04e78ba90ed4@linaro.org>
Hi,
On 02/08/2018 10:45 AM, Luis Machado wrote:
> Hi Kyrill,
>
> On 02/08/2018 09:48 AM, Kyrill Tkachov wrote:
>> Hi Luis,
>>
>> On 06/02/18 15:04, Luis Machado wrote:
>>> Thanks for the feedback Kyrill. I've adjusted the v2 patch based on your
>>> suggestions and re-tested the changes. Everything is still sane.
>>
>> Thanks! This looks pretty good to me.
>>
>>> Since this is ARM-specific and fairly specific, i wonder if it would be
>>> reasonable to consider it for inclusion at the current stage.
>>
>> It is true that the target maintainers can choose to take
>> such patches at any stage. However, any patch at this stage increases
>> the risk of regressions being introduced and these regressions
>> can come bite us in ways that are very hard to anticipate.
>>
>> Have a look at some of the bugs in bugzilla (or a quick scan of the
>> gcc-bugs list)
>> for examples of the ways that things can go wrong with any of the
>> myriad of GCC components
>> and the unexpected ways in which they can interact.
>>
>> For example, I am now working on what I initially thought was a
>> one-liner fix for
>> PR 84164 but it has expanded into a 3-patch series with a midend
>> component and
>> target-specific changes for 2 ports.
>>
>> These issues are very hard to catch during review and normal testing,
>> and can sometimes take months of deep testing by
>> fuzzing and massive codebase rebuilds to expose, so the closer the
>> commit is to a release
>> the higher the risk is that an obscure edge case will be unnoticed and
>> unfixed in the release.
>>
>> So the priority at this stage is to minimise the risk of destabilising
>> the codebase,
>> as opposed to taking in new features and desirable performance
>> improvements (like your patch!)
>>
>> That is the rationale for delaying committing such changes until the
>> start
>> of GCC 9 development. But again, this is up to the aarch64 maintainers.
>> I'm sure the patch will be a perfectly fine and desirable commit for
>> GCC 9.
>> This is just my perspective as maintainer of the arm port.
>
> Thanks. Your explanation makes the situation pretty clear and it sounds
> very reasonable. I'll put the patch on hold until development is open
> again.
>
> Regards,
> Luis
With GCC 9 development open, i take it this patch is worth considering
again?
Thanks,
Luis
next prev parent reply other threads:[~2018-05-07 14:28 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-02 14:38 [PATCH] " Luis Machado
2018-02-02 14:57 ` Kyrill Tkachov
2018-02-06 15:04 ` [PATCH, v2] " Luis Machado
2018-02-08 11:48 ` Kyrill Tkachov
2018-02-08 12:45 ` Luis Machado
2018-05-07 14:28 ` Luis Machado [this message]
2018-05-08 14:09 ` Kyrill Tkachov
2018-05-09 12:46 ` Luis Machado
2018-05-09 13:55 ` Kyrill Tkachov
2018-05-10 10:56 ` Luis Machado
2018-05-11 10:29 ` Kyrill Tkachov
2018-05-14 20:50 ` Luis Machado
2018-05-15 8:17 ` Kyrill Tkachov
2018-05-15 16:58 ` James Greenhalgh
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=d3889cba-56a3-6709-579f-d5384d75050c@linaro.org \
--to=luis.machado@linaro.org \
--cc=Richard.Earnshaw@arm.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=james.greenhalgh@arm.com \
--cc=kyrylo.tkachov@foss.arm.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).