From: Jeff Law <law@redhat.com>
To: Richard Biener <richard.guenther@gmail.com>,
gcc@gcc.gnu.org, Peter Bergner <bergner@vnet.ibm.com>
Cc: Vladimir N Makarov <vmakarov@redhat.com>,
Pat Haugen <pthaugen@linux.vnet.ibm.com>
Subject: Re: Why does IRA force all pseudos live across a setjmp call to be spilled?
Date: Mon, 05 Mar 2018 02:12:00 -0000 [thread overview]
Message-ID: <305d9c27-7043-70be-6ba2-c7675647f557@redhat.com> (raw)
In-Reply-To: <0F51D9FD-7F6C-453E-80FB-BE782B2E3C90@gmail.com>
On 03/04/2018 01:57 AM, Richard Biener wrote:
>
> I think posix says you have to mark such variables volatile. So I
> fully agree with your analysis of why setjmp isn't special for RA. It
> would be only making non-conforming code work by accident.
Note the code we're carrying around has its origins prior to the
introduction of volatile into the C standard. It may be the case that
we can and should rethink all this behavior in a modern world where
setjmp/longjmp semantics are better refined and programmers are expected
to use volatile to indicate the behavior they want.
I'm not sure I'd want to do that during stage4 though. Seems like a
gcc-9 kind of thing.
jeff
next prev parent reply other threads:[~2018-03-05 2:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-02 19:45 Peter Bergner
2018-03-02 19:55 ` Alexander Monakov
2018-03-02 21:26 ` Jeff Law
2018-03-03 3:28 ` Peter Bergner
2018-03-03 16:29 ` Jeff Law
2018-03-03 23:47 ` Peter Bergner
2018-03-04 0:30 ` Peter Bergner
2018-03-04 8:57 ` Richard Biener
2018-03-04 9:11 ` Andreas Schwab
2018-03-05 2:12 ` Jeff Law [this message]
2018-03-04 13:57 ` Eric Botcazou
2018-03-04 16:40 ` Peter Bergner
2018-03-04 17:39 ` Andreas Schwab
2018-03-05 0:16 ` Segher Boessenkool
2018-03-05 7:01 ` Eric Botcazou
2018-03-05 7:09 ` Eric Botcazou
2018-03-05 15:33 ` Segher Boessenkool
2018-03-05 16:18 ` Eric Botcazou
2018-03-06 16:20 ` Peter Bergner
2018-03-03 3:21 ` Vladimir Makarov
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