R600/SI: Mark the EXEC register as reserved

This prevents the machine verifier from complaining about uses of
an undefined physical register.

Reviewed-by: Vincent Lejeune<vljn at ovi.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192364 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/R600/SIRegisterInfo.cpp

@@ -25,6 +25,7 @@ SIRegisterInfo::SIRegisterInfo(AMDGPUTargetMachine &tm)
 
 BitVector SIRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   BitVector Reserved(getNumRegs());
+  Reserved.set(AMDGPU::EXEC);
   return Reserved;
 }