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Re: [i386, patch, RFC] HLE support in GCC
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Andi Kleen <andi at firstfloor dot org>, "H.J. Lu" <hjl dot tools at gmail dot com>, Kirill Yukhin <kirill dot yukhin at gmail dot com>, Jakub Jelinek <jakub at redhat dot com>
- Date: Tue, 10 Apr 2012 19:43:31 +0200
- Subject: Re: [i386, patch, RFC] HLE support in GCC
> > 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.
> It makes sense to combine the two. On x86 C++ atomic acquire/release
> means the compiler cannot move references outside. For HLE
> we really want the same, otherwise some of the memory references
> inside the transaction may not be transactional.
> So I think HLE_ACQUIRE should imply C++ acquire
> and HLE_RELEASE imply C++ release.
In this case, can we reverse this sentence and just emit "lock
xacquire" for MEMMODEL_ACQUIRE and "lock xrelease" for
MEMMODEL_RELEASE ? Do we need separate HLE_* defines or can we somehow
recycle existing C++11 memmodel defines?