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Re: RFC: LRA for x86/x86-64 [0/9]


On Fri, Sep 28, 2012 at 12:56 AM, Vladimir Makarov <vmakarov@redhat.com> wrote:
>   Originally I was to submit LRA at the very beginning of stage1 for
> gcc4.9 as it was discussed on this summer GNU Tools Cauldron.  After
> some thinking, I've decided to submit LRA now but only switched on for
> *x86/x86-64* target.  The reasons for that are
>   o I am already pretty confident in LRA for this target with the
>     point of reliability, performance, code size, and compiler speed.
>   o I am confident that I can fix LRA bugs and pitfalls which might be
>     recognized and reported during stage2 and 3 of gcc4.8.
>   o Wider LRA testing for x86/x86-64 will make smoother a hard transition of
>     other targets to LRA during gcc4.9 development.
>
>   During development of gcc4.9, I'd like to switch major targets to
> LRA as it was planned before.  I hope that all targets will be
> switched for the next release after gcc4.9 (although it will be
> dependent mostly on the target maintainers).  When/if it is done,
> reload and reload oriented machine-dependent code can be removed.
>
>   LRA project was reported on 2012 GNU Tools Cauldron
> (http://gcc.gnu.org/wiki/cauldron2012).  The presentation contains a
> high-level description of LRA and the project status.
>
>   The following patches makes LRA working for x86/x86-64. Separately
> patches mostly do nothing until the last patch switches on LRA for
> x86/x86-64.  Although compiler is bootstrapped after applying each
> patch in given order, the division is only for review convenience.
>
>   Any comments and proposals are appreciated.  Even if GCC community
> decides that it is too late to submit it to gcc4.8, the earlier reviews
> are always useful.

>From a release-manager point of view the patch is "in time" for 4.8, in that
it is during stage1 (which I expect to last another two to four weeks).  Note
that there is no such thing as "stage2" anymore but we go straight to
"stage3" (bugfixing mode, no new features) from stage1.  After three months
of stage3 we go into regression-fixes only mode for as long as there are
release-blocking bugs (regressions with priority P1).  You will have roughly
half a year to fix LRA for 4.8.0 after stage1 closes.

Thanks,
Richard.

>   The patches were successfully bootstrapped and tested for x86/x86-64.
>


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