From: Michael Matz <matz@suse.de>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jakub Jelinek <jakub@redhat.com>, "H.J. Lu" <hjl.tools@gmail.com>,
Alexander Monakov <amonakov@ispras.ru>,
Uros Bizjak <ubizjak@gmail.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] i386: Don't use frame pointer without stack access
Date: Mon, 07 Aug 2017 16:28:00 -0000 [thread overview]
Message-ID: <alpine.LSU.2.21.1708071821570.15613@wotan.suse.de> (raw)
In-Reply-To: <2c0c60fc-2bdc-9246-0165-cf6ef48e3e7e@linux.intel.com>
Hi,
On Mon, 7 Aug 2017, Arjan van de Ven wrote:
> I'm not surprised to see one.
> I'm surprised to see a useless one.
>
> The "perf" benefit is real, and that's why I asked for one... but the reorder
> made it an expensive 3 instruction nop for all intents and purposes.
> If the pop was just before the ret, sure. It's not.
Okay, that seems a reasonable request. But IMHO independend from the
issue of simply ignoring -fno-omit-frame-pointer to which I object.
> Maybe a different angle would be for a peephole phase to just eliminate
> the useless (even for those who do want a frame pointer) push/mov/pop
For instance.
Ciao,
Michael.
next prev parent reply other threads:[~2017-08-07 16:28 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-06 19:40 H.J. Lu
2017-08-07 6:21 ` Uros Bizjak
2017-08-07 13:15 ` Michael Matz
2017-08-07 13:21 ` Uros Bizjak
2017-08-07 13:25 ` H.J. Lu
2017-08-07 13:32 ` Michael Matz
2017-08-07 13:38 ` H.J. Lu
2017-08-07 13:49 ` Michael Matz
2017-08-07 14:06 ` Alexander Monakov
2017-08-07 15:39 ` H.J. Lu
2017-08-07 15:43 ` Jakub Jelinek
2017-08-07 16:06 ` Arjan van de Ven
2017-08-07 16:16 ` Michael Matz
2017-08-07 16:19 ` Arjan van de Ven
2017-08-07 16:21 ` H.J. Lu
2017-08-07 16:28 ` Michael Matz [this message]
2017-08-07 20:05 ` Richard Sandiford
2017-08-08 16:38 ` H.J. Lu
2017-08-08 17:01 ` Richard Biener
2017-08-08 17:34 ` Richard Sandiford
2017-08-08 17:36 ` Richard Sandiford
2017-08-08 18:00 ` Richard Biener
2017-08-08 18:29 ` H.J. Lu
2017-08-09 7:53 ` Richard Sandiford
2017-08-09 11:22 ` Richard Biener
2017-08-09 11:31 ` H.J. Lu
2017-08-09 11:59 ` Michael Matz
2017-08-09 12:27 ` H.J. Lu
2017-08-09 15:04 ` Andi Kleen
2017-08-09 15:05 ` Arjan van de Ven
2017-08-09 15:14 ` H.J. Lu
2017-08-09 15:26 ` Andi Kleen
2017-08-09 17:28 ` H.J. Lu
2017-08-09 18:31 ` H.J. Lu
2017-08-10 7:19 ` Richard Sandiford
2017-08-10 7:40 ` Richard Sandiford
2017-08-10 7:51 ` Uros Bizjak
2017-08-10 14:07 ` H.J. Lu
2017-08-08 17:05 ` Uros Bizjak
2017-08-07 18:40 ` Uros Bizjak
2017-08-07 13:38 ` Andreas Schwab
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