[polly] r225067 - Drop all constant scheduling dimensions

[Tobias Grosser]

On 02.01.2015 00:01, Tobias Grosser wrote:
> Author: grosser
> Date: Thu Jan  1 17:01:11 2015
> New Revision: 225067
>
> URL: http://llvm.org/viewvc/llvm-project?rev=225067&view=rev
> Log:
> Drop all constant scheduling dimensions
>
> Schedule dimensions that have the same constant value accross all statements do
> not carry any information, but due to the increased dimensionality of the
> schedule cost compile time. To not pay this cost, we remove constant dimensions
> if possible.

This patch improved the compile time on 65 benchmarks with 13 benchmarks 
showing more than -10% compile time reduction:

http://llvm.org/perf/db_default/v4/nts/16172?num_comparison_runs=0&test_filter=&test_min_value_filter=&aggregation_fn=median&MW_confidence_lv=0.01&compare_to=16157&submit=Update

The current compile and run-time comparision between clang -O3 and clang 
-O3 -polly is visible here:

http://llvm.org/perf/db_default/v4/nts/16172?num_comparison_runs=0&test_filter=&test_min_value_filter=&aggregation_fn=median&MW_confidence_lv=0.01&compare_to=16171&submit=Update

Cheers,
Tobias