IRA issue with shuffle copies...

[Vladimir Makarov]

On 01/10/2012 12:55 PM, Peter Bergner wrote:
> On Tue, 2012-01-10 at 12:20 -0500, Vladimir Makarov wrote:
>>> Do we really need or want to create shuffle copies for insns that do not
>>> have a two operand constraint?
>> Yes, I think so.  As I remember I did some benchmarking and it gave some
>> "order" in hard register assignments and improved code slightly (at
>> least for SPEC2000) even for 3-ops insn architectures.
>
> Ok, I'll have someone on my team kick off this patch on ppc, but it would
> be nice if someone else could do the runs on x86/x86_64 or other cpus that
> might be affected that we don't have access to.
>
There is no visible effect of the patch on SPECFP2000 performance and 
size (the size increase is only about 0.02%) for x86 and x86-64.

The patch does worsen performance of SPECINT2000 on x86 (about 0.5%) and 
x86-64 (about 0.3%).  x86-64 SPECINT200 code size increase is about 
0.05% and there is no visible change in code size on x86.

So I'd say the patch does not work for x86/x86-64.