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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Eric Botcazou <ebotcazou@adacore.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH 1/3] function: Do the CLEANUP_EXPENSIVE after shrink-wrapping, not before
Date: Tue, 17 May 2016 09:18:00 -0000	[thread overview]
Message-ID: <20160517091758.GC18363@gate.crashing.org> (raw)
In-Reply-To: <20909191.oPg4YIUu4L@polaris>

On Tue, May 17, 2016 at 11:08:53AM +0200, Eric Botcazou wrote:
> > How would it?  The shrink-wrapping algorithms do not much care how you
> > write your control flow.  The only things I can think of are drastic
> > things like removing some dead code, or converting a switch to a direct
> > jump, but those had better be done for the immediately preceding passes
> > already (register allocation).
> 
> But the compiler didn't wait until after shrink-wrapping to emit multiple 
> epilogues and can still do that w/o shrink-wrapping.

It will only ever generate a single epilogue (unless you also count
sibcall epilogues), and that is done after shrink-wrapping.  Or you mean
something else and I just don't see it.

> > I can put back a  cleanup_cfg (0)  in front if that seems less tricky
> > (or just safer)?
> 
> I think you need to evaluate the effects of the change on a set of sources.

Yeah I'll do that, thanks for the idea.


Segher

  reply	other threads:[~2016-05-17  9:18 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-17  1:09 Segher Boessenkool
2016-05-17  1:09 ` [PATCH 3/3] function: Restructure *logue insertion Segher Boessenkool
2016-05-19  8:04   ` Segher Boessenkool
2016-05-19 22:00   ` Jeff Law
2016-05-19 22:20     ` Segher Boessenkool
2016-05-20  9:28       ` Thomas Schwinge
2016-05-20 13:21         ` Thomas Schwinge
2016-05-20 14:47           ` Nathan Sidwell
2016-05-20 15:35             ` Segher Boessenkool
2016-05-20 21:27         ` Segher Boessenkool
2016-05-17  1:09 ` [PATCH 2/3] function: Factor out make_*logue_seq Segher Boessenkool
2016-05-17 20:35   ` Jeff Law
2016-05-18 17:17   ` H.J. Lu
2016-05-18 18:11     ` Segher Boessenkool
2016-05-18 18:20       ` H.J. Lu
2016-05-18 18:24         ` H.J. Lu
2016-05-18 18:35         ` Segher Boessenkool
2016-05-18 22:13           ` Segher Boessenkool
2016-05-19  7:16             ` Jakub Jelinek
2016-05-19  7:28               ` Segher Boessenkool
2016-05-19  7:41                 ` Jakub Jelinek
2016-05-19 17:20               ` Jeff Law
2016-05-17  8:06 ` [PATCH 1/3] function: Do the CLEANUP_EXPENSIVE after shrink-wrapping, not before Eric Botcazou
2016-05-17  8:47   ` Segher Boessenkool
2016-05-17  9:08     ` Eric Botcazou
2016-05-17  9:18       ` Segher Boessenkool [this message]
2016-05-17 22:23         ` Segher Boessenkool
2016-05-17 22:34           ` Eric Botcazou

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