[PATCH] Add HLE target feature

[Michael Liao]

Hi Jeffrey

On Wed, 2013-02-20 at 17:05 -0800, Jeffrey Yasskin wrote:
> > On Wed, 2013-02-20 at 16:51 -0800, Jeffrey Yasskin wrote:
> >> Don't take me as authoritative, but it seems sensible to add clang and
> >> LLVM support for these instructions if there's enough of a spec for
> >> the language-level operations to describe when the compiler can
> >> optimize around them. For example, the C11 atomics allow the compiler
> >> to reorder non-atomic operations across atomic operations in certain
> >> circumstances.
> >>
> >> Is there a description of the language-level semantics of the
> >> operations you're adding, or does it all rely on the instruction set
> >> definition? Could a compiler decide that it's a good idea to add these
> >> prefixes on its own?
> 
> On Wed, Feb 20, 2013 at 4:59 PM, Michael Liao <michael.liao at intel.com> wrote:
> > These patches are developed to follow GCC's approach supporting HLE.
> 
> The patch you pointed to in GCC didn't add documentation there either.
> I'm nervous about undocumented features.

This feature will be in gcc-4.8. This link gives more on the design,
http://gcc.gnu.org/ml/gcc-patches/2012-04/msg01073.html These macros are
documented according to
http://gcc.gnu.org/ml/gcc-patches/2012-11/msg00750.html. I need confirm
that whether the document is committed or not.

Yours
- Michael