From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Howells <dhowells@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: cmpxchg and x86 flags output
Date: Wed, 22 Jun 2016 10:49:06 -0700 [thread overview]
Message-ID: <c4704d53-e6eb-4cc4-4d3f-023ff36157b6@zytor.com> (raw)
In-Reply-To: <CA+55aFxva_dW+=10JA9G1d1uAW1rHimLS5jGVUeNxfFepFzA9A@mail.gmail.com>
On 06/22/16 10:11, Linus Torvalds wrote:
>
> I thought Richard Henderson already had a patch for the condition code
> asm outputs, but maybe I misremember.
>
It is already in the released version of gcc 6.1; there is a patchset in
-tip already for using it for everything other than cmpxchg using the
CC_SET/CC_OUT macros I proposed a while ago. cmpxchg is special because
it requires API changes to take advantage of, which as far as I
understand happens to be exactly the API changes that David has already
implemented. Apparently some other architectures really can benefit
from intrinsics, so that is okay; we can use inline asm with flags
output on x86.
-hpa
prev parent reply other threads:[~2016-06-22 17:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 23:53 cmpxchg and x86 flags output H. Peter Anvin
2016-06-15 8:50 ` Peter Zijlstra
2016-06-16 22:21 ` H. Peter Anvin
2016-06-21 9:06 ` David Howells
2016-06-21 17:00 ` H. Peter Anvin
2016-06-21 17:24 ` H. Peter Anvin
2016-06-22 0:09 ` H. Peter Anvin
2016-06-22 16:14 ` David Howells
2016-08-19 17:22 ` H. Peter Anvin
2016-08-22 15:13 ` David Howells
2016-06-22 16:11 ` David Howells
2016-06-22 16:36 ` H. Peter Anvin
2016-06-22 17:11 ` Linus Torvalds
2016-06-22 17:49 ` H. Peter Anvin [this message]
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