From: Segher Boessenkool <segher@kernel.crashing.org>
To: Bernd Schmidt <bschmidt@redhat.com>
Cc: gcc-patches@gcc.gnu.org, dje.gcc@gmail.com
Subject: Re: [PATCH 8/9] shrink-wrap: shrink-wrapping for separate concerns
Date: Tue, 19 Jul 2016 15:35:00 -0000 [thread overview]
Message-ID: <20160719153515.GB26941@gate.crashing.org> (raw)
In-Reply-To: <f5dcd704-db71-839c-ee12-47fb3ac595e3@redhat.com>
On Tue, Jul 19, 2016 at 04:49:26PM +0200, Bernd Schmidt wrote:
> >But you need the profile to make even reasonably good decisions.
>
> I'm not worried about making cost decisions: as far as I'm concerned
> it's perfectly fine for that. I'm worried about correctness - you can't
> validly save registers inside a loop.
Of course you can. It needs to be paired with a restore; and we do
that just fine.
Pretty much *all* implementations in the literature do this, fwiw.
> So IMO there needs to be an
> additional cfg-based check that verifies whether the bb where we want to
> place parts of the prologue is guaranteed to be executed at most once.
That is equivalent to not doing this optimisation *at all*.
Segher
next prev parent reply other threads:[~2016-07-19 15:35 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-08 1:48 [PATCH 0/9] separate shrink-wrapping Segher Boessenkool
2016-06-08 1:48 ` [PATCH 1/9] separate shrink-wrap: New command-line flag, status flag, hooks, and doc Segher Boessenkool
2016-06-08 1:48 ` [PATCH 2/9] cfgcleanup: Don't confuse CFI when -fshrink-wrap-separate Segher Boessenkool
2016-06-08 1:48 ` [PATCH 3/9] dce: Don't dead-code delete separately wrapped restores Segher Boessenkool
2016-06-08 1:53 ` [PATCH 6/9] sel-sched: Don't mess with register restores Segher Boessenkool
2016-06-08 1:53 ` [PATCH 4/9] regrename: Don't rename restores Segher Boessenkool
2016-06-08 1:54 ` [PATCH 7/9] cprop: Leave RTX_FRAME_RELATED_P instructions alone Segher Boessenkool
2016-06-08 1:54 ` [PATCH 5/9] regrename: Don't run if function was separately shrink-wrapped Segher Boessenkool
2016-06-08 9:18 ` Bernd Schmidt
2016-09-09 18:41 ` Jeff Law
2016-09-09 20:56 ` Segher Boessenkool
2016-09-09 23:12 ` Jeff Law
2016-09-10 6:59 ` Segher Boessenkool
2016-09-12 16:36 ` Jeff Law
[not found] ` <CAGWvny=fHHZtKF4_D2098+3PTPPzxtg3EjKDWHyJwUxz8g_tEA@mail.gmail.com>
[not found] ` <CAGWvnymZVg_FR_PHqhwkgrAkHDntVMEiG4shfst_GA9OnZKvWg@mail.gmail.com>
[not found] ` <CAGWvnykQ3oz0UpcF6U1WYivbJww65h2EH5n3FocQ8JGY9hrOrA@mail.gmail.com>
2016-09-12 17:04 ` Jeff Law
2016-09-14 13:08 ` Segher Boessenkool
2016-09-14 13:18 ` Bernd Schmidt
2016-09-14 14:01 ` Segher Boessenkool
2016-09-14 14:54 ` Bernd Schmidt
2016-09-14 16:33 ` Segher Boessenkool
2016-09-14 19:10 ` Jeff Law
2016-09-14 17:55 ` Jeff Law
2016-09-14 19:13 ` Segher Boessenkool
2016-09-14 19:36 ` Jeff Law
2016-09-14 18:21 ` Jeff Law
2016-09-14 19:13 ` Segher Boessenkool
2016-09-14 19:38 ` Jeff Law
2016-09-14 22:34 ` Segher Boessenkool
2016-09-15 17:28 ` Jeff Law
2016-09-19 17:11 ` Segher Boessenkool
2016-09-14 20:04 ` Jeff Law
2016-09-14 22:51 ` Segher Boessenkool
2016-06-08 2:03 ` [PATCH 8/9] shrink-wrap: shrink-wrapping for separate concerns Segher Boessenkool
2016-07-15 12:42 ` Bernd Schmidt
2016-07-18 16:34 ` Segher Boessenkool
2016-07-18 17:03 ` Bernd Schmidt
2016-07-19 14:46 ` Segher Boessenkool
2016-07-19 14:49 ` Bernd Schmidt
2016-07-19 15:35 ` Segher Boessenkool [this message]
2016-07-20 11:23 ` Bernd Schmidt
2016-07-20 15:06 ` Segher Boessenkool
2016-06-08 2:04 ` [PATCH 9/9] rs6000: Separate shrink-wrapping Segher Boessenkool
2016-06-08 11:56 ` [PATCH 0/9] separate shrink-wrapping Bernd Schmidt
2016-06-08 12:45 ` Eric Botcazou
2016-06-08 15:16 ` Segher Boessenkool
2016-06-08 16:43 ` Bernd Schmidt
2016-06-08 17:26 ` Segher Boessenkool
2016-06-29 23:06 ` Bernd Schmidt
2016-06-29 23:24 ` Segher Boessenkool
2016-07-04 8:57 ` Segher Boessenkool
2016-06-14 21:24 ` Segher Boessenkool
2016-07-08 10:42 ` Bernd Schmidt
2016-07-08 12:11 ` Segher Boessenkool
2016-07-08 13:16 ` David Malcolm
2016-07-08 13:45 ` Segher Boessenkool
2016-07-08 14:35 ` Bill Schmidt
2016-06-09 16:12 ` Jeff Law
2016-06-09 19:57 ` Segher Boessenkool
2016-06-28 0:22 ` PING " Segher Boessenkool
2016-07-07 10:16 ` PING x2 " Segher Boessenkool
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