From: Michael Matz <matz@suse.de>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Alexander Monakov <amonakov@ispras.ru>,
Jakub Jelinek <jakub@redhat.com>,
Martin Sebor <msebor@gmail.com>,
Gcc Patch List <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] diagnose unsupported uses of hardware register variables (PR 88000)
Date: Mon, 19 Nov 2018 12:59:00 -0000 [thread overview]
Message-ID: <alpine.LSU.2.21.1811191258220.5354@wotan.suse.de> (raw)
In-Reply-To: <20181116221152.GK23873@gate.crashing.org>
Hi,
On Fri, 16 Nov 2018, Segher Boessenkool wrote:
> > I.e. like volatile they can arbitrarily change their value. I don't
> > know if other peoples mind model is similar, but it certainly is the
> > model that is implemented in the GIMPLE pipeline (and if memory serves
> > well of the RTL pipeline as well).
> >
> > Copying outof/into pseudos around asms serves no purpose with that
> > model, it rather makes regvars somewhat "safer" to use, without
> > actually making them safer (there _is_ nothing safe about them).
>
> The only supported case is for inputs and outputs to extended asm.
> Maybe we should just come up with a syntax so you can specify hard regs
> for that directly (without needing a separate regclass for every reg).
I would like that, yes. (Of course backward compat would have us support
the historic usage for some time, but still ...)
Ciao,
Michael.
next prev parent reply other threads:[~2018-11-19 12:59 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 12:22 Segher Boessenkool
2018-11-14 12:27 ` Jakub Jelinek
2018-11-14 12:33 ` Alexander Monakov
2018-11-14 13:53 ` Segher Boessenkool
2018-11-14 15:50 ` Alexander Monakov
2018-11-14 17:47 ` Segher Boessenkool
2018-11-14 18:01 ` Alexander Monakov
2018-11-15 15:54 ` Michael Matz
2018-11-15 16:23 ` Alexander Monakov
2018-11-16 15:21 ` Michael Matz
2018-11-16 16:28 ` Alexander Monakov
2018-11-16 16:43 ` Michael Matz
2018-11-16 22:12 ` Segher Boessenkool
2018-11-19 12:59 ` Michael Matz [this message]
2018-11-19 17:18 ` Segher Boessenkool
2018-11-14 13:47 ` Segher Boessenkool
-- strict thread matches above, loose matches on Subject: below --
2018-11-14 4:11 Martin Sebor
2018-11-14 9:39 ` Alexander Monakov
2018-11-15 22:34 ` Martin Sebor
2018-11-14 9:48 ` Jakub Jelinek
2018-11-14 11:35 ` Segher Boessenkool
2018-11-14 11:40 ` Jakub Jelinek
2018-11-14 11:50 ` Segher Boessenkool
2018-11-14 12:00 ` Jakub Jelinek
2018-11-14 12:11 ` Segher Boessenkool
2018-11-14 12:14 ` Jakub Jelinek
2018-11-15 18:31 ` Martin Sebor
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