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Re: Combine four insns
On Fri, Aug 6, 2010 at 11:56 AM, Vladimir N. Makarov
<vmakarov@redhat.com> wrote:
> On 08/06/2010 01:22 PM, Steven Bosscher wrote:
>> Agreed. There is the work from Preston Briggs, but that appears to
>> have gone no-where, unfortunately.
>>
> IMHO the code should have become public if we want to see a progress on the
> problem solution. ?But it is a Google property and they probably decided not
> to give it gcc community. ?Although I heard that Ken Zadeck has access to
> it. ?We will see what the final result will be.
>
> I only can guess from speculations on info I have that Preston's code is
> probably not so valuable for GCC because as I understand the backend was
> only specialized for x86/x86_64.
The work by Preston and others was incomplete, was x86 specific, did
not work with existing MD files, and the tests that worked showed that
it didn't do any better than IRA. So the project was cancelled.
There is nothing secret about the code, but since it essentially means
replacing the RTL backend I'm not sure it's useful in the context of
gcc. It could only ever have been used if it were significantly
better than what we have today.
Ian