Subzero: Automatically infer regalloc preferences and overlap.

src/IceInst.h

Index: src/IceInst.h
diff --git a/src/IceInst.h b/src/IceInst.h
index 5c07dc0b47e34ff921d756c860504561047bb25f..10caa8b2012e476172b668f764fd27a319cc5ce0 100644
--- a/src/IceInst.h
+++ b/src/IceInst.h
@@ -92,6 +92,8 @@ public:
     return NodeList();
   }
 
+  virtual bool isSimpleAssign() const { return false; }
+
   void livenessLightweight(Cfg *Func, llvm::BitVector &Live);
   void liveness(InstNumberT InstNumber, llvm::BitVector &Live,
                 Liveness *Liveness, const CfgNode *Node);
@@ -233,6 +235,7 @@ public:
     return new (Func->allocateInst<InstAssign>())
         InstAssign(Func, Dest, Source);
   }
+  virtual bool isSimpleAssign() const { return true; }
   virtual void dump(const Cfg *Func) const;
   static bool classof(const Inst *Inst) { return Inst->getKind() == Assign; }