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Re: [rtl-optimization] Improve Data Prefetch for IA-64


>On Mon, 28 Mar 2005, James E Wilson wrote:
>> Steven Bosscher wrote:
>>> OK, so I know this is not a popular subject, but 
can we *please* stop
>>> working on loop.c and focus on getting the new RTL 
and tree loop passes
>>> to do what we want?
>> I don't think anyone is objecting to this. [...]
>> I would however make a distinction here between new 
development work and
>> maintenance.  It would be better if new development 
work happened in the new
>> loop optimizer.  However, we still need to do 
maintenance work in loop.c.
>
>...and since Canqun reported 2.5% improvement on SPEC 
CFP2000 on ia64 with 
>his current patch, I really think we should consider 
it.
>

Besides this, I¡¯ve got another patch for improving 
general induction variable optimizations defined in 
loop.c. With these two patches and properly setting 
the loop unrolling parameters, the tests of both NAS 
and SPEC CPU2000 benchmarks on IA-64 1GHz system show 
a good result.

1. The following table shows the test result of NAS 
benchmarks:
	Gcc-20050404	Gcc-20050404	Ratio
			+ Optimized.
Bt.W	22.16s		22.68s		0.98
Cg.A	9.23s		7.45s		1.24
Ep.W	12.3s		11.97s		1.03
Ft.A	38.41s		25.98s		1.48
Is.B	34.94s		33.47s		1.04
Lu.W	32.93s		31.59s		1.04
Mg.A	21.91s		14.64s		1.50
Sp.W	59.71s		55.67s		1.07
Geomean					1.16

"Gcc-20050404" is the GCC mainline version dated on 
April 4, 2005. It includes my previous patch of 
RECORD_TYPE for COMMON blocks without equivalence 
objects. The compile options for ¡°Gcc-20050404¡± is 
¡°-O3 -funroll-loops -fprefetch-loop-arrays¡±, and ¡°-
O3 -funroll-loops -fprefetch-loop-arrays --param max-
unrolled-insns=600 --param max-average-unrolled-
insns=320¡± for¡°Gcc-20050404+Optimized¡±. 

2. The SPEC CFP2000 test uses the same options as 
above.
   ¡°Gcc-20050404¡± got 426 SPEC ratio, and ¡°Gcc-
20050404 + Optimized¡± got 459 SPEC ratio. You can 
download the attachments to see more details. And if 
the address giv splitting were not miss in the new 
loop unroller, the SPEC ratio up to 513 can be 
expected. 

>We all know how hard it is to get this kind of 
improvement on any of the 
>SPECs -- and in fact improving the current optimizers 
will make raise >the
>bar for the new ones. ;-)
>
>Question is: who is going review/potentially approve 
this patch?
>
>Gerald


Canqun Yang
Creative Compiler Research Group.
National University of Defense Technology, China.

Attachment: CFP2000.154.pdf
Description: Adobe PDF document

Attachment: CFP2000.155.pdf
Description: Adobe PDF document


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