[LLVMdev] Help adding the Bullet physics sdk benchmark to the LLVM test suite?

Evan Cheng evan.cheng at apple.com
Thu Dec 17 22:48:17 PST 2009

On Dec 15, 2009, at 5:15 PM, Erwin Coumans wrote:

> The linux builds are not using SSE right now, but the vector data is
> 16-byte aligned on all platforms.
> So if you port this SSE code to another platform (Linux, Altivec,
> NEON), you could contribute it back to Bullet?
> The most interesting SSE part is the innerloop of the constraint
> solver: http://tinyurl.com/ydoapct

Sounds like a very interesting SSE test.

> Some developers replaced some linear algebra functions (in
> Bullet/LinearMath) with VFP/Neon
> optimizations, but haven't contributed this back.
> This NEON/VFP, part of the an open source iPhone project, could be a
> starting point for this:
> http://tinyurl.com/y9gv3e8

Very unfortunate it's using inline asm. Are there developers should are interested in using NEON intrinsics?


> Thanks,
> Erwin
> 2009/12/15 Anton Korobeynikov <anton at korobeynikov.info>
>> Hello, Erwin
>>> Although most of this is plain portable C++ perhaps LLVM can auto-vectorize
>>> some of this?
>> Well, I doubt so, unfortunately - LLVM does not have any autopar these days
>>> There is a little bit of hand optimized x86 SSE code. This is only enabled
>>> on 32bit Windows and Mac OSX Intel builds.
>> Ok. What's about Linux builds? Are there any other implementations
>> e.g. altivec / NEON ?
>>> You could take Bullet/Demos/Benchmarks as a starting point, and modify it so
>>> it fits the LLVM test suite?
>> Ok, will do.
>>> What hardware/platforms does the LLVM test suite run on typically?
>> So far 32 and 64 bit Linux and MacOS, 32-bit ppc/darwin. Also, there
>> is special "small" mode mainly designed for stuff like ARM.
>> It will be nice (in theory) to have some NEON/VFP code, since the
>> testsuite currently lacks any beanchmark for this.
>> --
>> With best regards, Anton Korobeynikov
>> Faculty of Mathematics and Mechanics, Saint Petersburg State University
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