[Mesa-dev] llvmPipe on ARM (CortexA-9)

[Roland Scheidegger]

Am 18.04.2012 14:02, schrieb Vijay:
> Hello,
> Can we use llvmpipe for arm architecture.(Specifically ARM cortexA-9) ??
> 
> I tried & found below error.
> 
> Unhandled instruction encoding format!
> UNREACHABLE executed at ARMCodeEmitter.cpp:534!
> Aborted
> 
> Version used : llvmpipe3.0,Mesa-8.0
> 
> Any hint or info will be helpfull.
> 

As José said, noone tried so far. I don't know how good the llvm arm
backend is, specifically for handling vector instructions it might not
be quite up to the task, or the JIT might not work too well. I found
some references saying old arm jit is 100% broken for VFP/NEON, which
means mc-jit is needed, so it's probably not going to work right now.

Oh and is this a Cortex-A9 with NEON? Some of the Cortex-A9 (ok I only
know of one) don't have NEON, in which case with some luck the backend
might still generate code which works but it's probably not too useful.
I (very) quickly glanced over the neon instruction set, looks like it
has pretty much everything needed for "reasonable" code generation. But
in any case, that's certainly secondary issues if the jit doesn't work
at all...

Roland