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Re: [i386, patch, RFC] HLE support in GCC
- From: Jakub Jelinek <jakub at redhat dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Kirill Yukhin <kirill dot yukhin at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 10 Apr 2012 16:44:32 +0200
- Subject: Re: [i386, patch, RFC] HLE support in GCC
- References: <CAGs3Rfu6kiQhDPXy_QmEyKzs-FXPO9i74VUEUPoHX0WiEaz_iA@mail.gmail.com> <20120307111008.GK16117@tyan-ft48-01.lab.bos.redhat.com> <CAMe9rOqC1fckmVN9MOXWMhG-2jhHYtGCsrXCdT4ZDgp1J39Msw@mail.gmail.com> <CAGs3Rft_0Cs6v3AP_LH2tbbqrym5rf1A4MJ+6fn1T37=BEzrbw@mail.gmail.com> <CAMe9rOqKWyfumpjuLyNGwAxdfzU9XmMDcj0vq4t1CefKJZtg5w@mail.gmail.com> <20120308150912.GS16117@tyan-ft48-01.lab.bos.redhat.com> <CAGs3RftVUdWy=jqfonJFLsyuT6mWjm_0Bdc2Dqjgtd9qNGDRXA@mail.gmail.com> <CAMe9rOrw5mNk=0NX3C74x4v1yEFy7VMTex6QDTEvE1UX+E6P4w@mail.gmail.com>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Tue, Apr 10, 2012 at 07:42:53AM -0700, H.J. Lu wrote:
> > Attached patch implements HLE support for __atomic_compare_exchange_n.
> >
> > So, to emit HLE prefix, it is possible to do:
> > int
> > foo2 (int *p, int oldv, int newv)
> > {
> > ?__atomic_compare_exchange_n (p, &oldv, newv, 0, __ATOMIC_ACQUIRE |
> > __ATOMIC_USE_HLE, __ATOMIC_ACQUIRE);
> > ?return oldv;
> > }
>
> This is wrong since HLE ACQUIRE/RELEASE has nothing to do with
> C++ atomic acquire/release. You can have HLE RELEASE with C++
> atomic acquire.
Yes, of course, there should be two bits for HLE rather than one.
Jakub