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From: Jeff Law <law@redhat.com>
To: Segher Boessenkool <segher@kernel.crashing.org>,
	       Bernd Schmidt <bschmidt@redhat.com>
Cc: gcc-patches@gcc.gnu.org, dje.gcc@gmail.com
Subject: Re: [PATCH 5/9] regrename: Don't run if function was separately shrink-wrapped
Date: Wed, 14 Sep 2016 17:55:00 -0000	[thread overview]
Message-ID: <2c75f739-1121-bdb4-19cb-92d798225cc4@redhat.com> (raw)
In-Reply-To: <20160914135515.GF4896@gate.crashing.org>

On 09/14/2016 07:55 AM, Segher Boessenkool wrote:
> On Wed, Sep 14, 2016 at 03:08:21PM +0200, Bernd Schmidt wrote:
>> On 09/14/2016 03:04 PM, Segher Boessenkool wrote:
>>> Then rs6000 (and many other ports probably) will just turn it off again.
>>> It is actively harmful.
>>
>> The data that was posted showed a code size decrease on a number of
>> targets. I'm really not sure where this irrational hate for regrename
>> comes from.
>
> It increases the number of active, "young" registers per thread.
Yea, it'll certainly do that and I can imagine a design which would have 
that property.  And there's other designs which benefit from spreading 
across the register file as much as possible.

Which argues there needs to be a way to tune or disable the pass.

Jeff

  parent reply	other threads:[~2016-09-14 17:52 UTC|newest]

Thread overview: 62+ 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 3/9] dce: Don't dead-code delete separately wrapped restores 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  1:53 ` [PATCH 4/9] regrename: Don't rename restores Segher Boessenkool
2016-06-08  1:53 ` [PATCH 6/9] sel-sched: Don't mess with register restores Segher Boessenkool
2016-06-08  1:54 ` [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 [this message]
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  1:54 ` [PATCH 7/9] cprop: Leave RTX_FRAME_RELATED_P instructions alone 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
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
2016-08-01  1:43 [PATCH v2 0/9] Separate shrink-wrapping Segher Boessenkool
2016-08-01  2:12 ` [PATCH 5/9] regrename: Don't run if function was separately shrink-wrapped Segher Boessenkool
2016-09-08 17:54   ` Jeff Law

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