[Mesa-dev] [PATCH] R600/SI: Use source scheduler

[Christian König]

Am 07.03.2013 17:05, schrieb Michel Dänzer:
> From: Michel Dänzer <michel.daenzer at amd.com>
>
> This is certainly not the last word on scheduling for this target, but
> right now this allows a few apps to run / finish with radeonsi, most
> notably UT2004 / Lightsmark. They fail to compile some shaders with the
> default scheduler because it ends up trying to spill registers, which
> we don't support yet (and which is probably a bad idea in general for
> performance if it can be avoided).
>
> NOTE: This is a candidate for the Mesa stable branch.
>
> Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

BTW: I played around with making the SMRD patterns trivial 
rematerializable, that should reduce the register pressure for SGPRs 
quite a bit. But unfortunately I couldn't find an use case where we run 
out of SGPRs before running out of VGPRs. Just leave me a note (or the 
shader code) if you got such a use case.

Christian.

> ---
>   lib/Target/R600/SIISelLowering.cpp | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/lib/Target/R600/SIISelLowering.cpp b/lib/Target/R600/SIISelLowering.cpp
> index cc53488..b9cc09f 100644
> --- a/lib/Target/R600/SIISelLowering.cpp
> +++ b/lib/Target/R600/SIISelLowering.cpp
> @@ -68,6 +68,8 @@ SITargetLowering::SITargetLowering(TargetMachine &TM) :
>     setTargetDAGCombine(ISD::SELECT_CC);
>   
>     setTargetDAGCombine(ISD::SETCC);
> +
> +  setSchedulingPreference(Sched::Source);
>   }
>   
>   SDValue SITargetLowering::LowerFormalArguments(