[LLVMdev] Goog test-cases for a new register allocator

[David Greene]

On Wednesday 02 April 2008 03:06, Roman Levenstein wrote:
> Hi,
>
> As I mentioned some time ago on the mailing list, I'm working on the
> implementation of the Sarkar's Extended Linear Scan algorithm for LLVM.

Cool!

> For testing and debugging of this algorithm, I need some good
> test-cases that check different functionalities of the register
> allocator, e.g.:
>  - test-cases involving a lot of spilling
>  - test-cases using pre-colored registers, e.g. like the EAX register
> used by the division instruction on X86
>  - test-cases making use of different (partially aliasing)
> register-classes at the same-time
>  - test-cases where the caller-save vs callee-save choices of registers
> play a big role.
>
> I think these requirements are not specific for my allocator only, but
> are important for checking any register allocator. May be someone
> (Fernando? David? Evan?) who was working on register allocators has
> found a good set of examples covering some of the topics? Or may be
> someone knows good examples due to the fact that current register
> allocators perform too bad on it? ;-)

I've found the NAS Parallel Benchmarks to be quite a good workout:

http://www.nas.nasa.gov/Resources/Software/npb.html

They are medium-sized benchmarks, so substantial without being totally
overwhelming.  They manifest pretty much all of your points above.  The
basic linear scan algorithm seems to do fairly well on them so it makes
for a good comparison.

I use version 2.3, the serial flavor (yes, I understand the irony :) ).

                                                 -Dave