R600/SI: Use source scheduler

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.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 176687

diff --git a/llvm/lib/Target/R600/SIISelLowering.cpp b/llvm/lib/Target/R600/SIISelLowering.cpp
index fead115..063f5fa 100644 (file)
--- a/llvm/lib/Target/R600/SIISelLowering.cpp
+++ b/llvm/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(