Subzero: Minor refactoring/additions in preparation for phi edge splitting.

src/IceInst.h

Index: src/IceInst.h
diff --git a/src/IceInst.h b/src/IceInst.h
index bbd817b52f978b7d973bdfbc0d35f2ba53e4115d..0a47e1a50821880994e1c52fc139221abc612973 100644
--- a/src/IceInst.h
+++ b/src/IceInst.h
@@ -554,6 +554,7 @@ public:
   }
   void addArgument(Operand *Source, CfgNode *Label);
   Operand *getOperandForTarget(CfgNode *Target) const;
+  CfgNode *getLabel(SizeT Index) const { return Labels[Index]; }
   void livenessPhiOperand(LivenessBV &Live, CfgNode *Target,
                           Liveness *Liveness);
   Inst *lower(Cfg *Func);