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

Erwin Coumans erwin.coumans at gmail.com
Tue Dec 15 17:15:43 PST 2009

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

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:


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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