diff --git a/src/mapleall/maple_me/include/me_ir.h b/src/mapleall/maple_me/include/me_ir.h
index 3051f62e7b4188b0bed0618ec0635ee7c34ea88a..376ef4c51255fab495ebecab04d6473cd47eb384 100644
--- a/src/mapleall/maple_me/include/me_ir.h
+++ b/src/mapleall/maple_me/include/me_ir.h
@@ -230,6 +230,10 @@ class ScalarMeExpr : public MeExpr {
     return ost;
   }
 
+  void SetOst(OriginalSt *o) {
+    ost = o;
+  }
+
   OStIdx GetOstIdx() const {
     return ost->GetIndex();
   }
@@ -294,7 +298,22 @@ class ScalarMeExpr : public MeExpr {
     def.defMustDef = &defMustDef;
   }
 
+  PregIdx GetRegIdx() const {
+    ASSERT(ost->IsPregOst(), "GetPregIdx: not a preg");
+    return ost->GetPregIdx();
+  }
+
+  bool IsNormalReg() const {
+    ASSERT(ost->IsPregOst(), "GetPregIdx: not a preg");
+    return ost->GetPregIdx() >= 0;
+  }
+
   BB *GetDefByBBMeStmt(const Dominance&, MeStmtPtr&) const;
+  void Dump(const IRMap*, int32 indent = 0) const override;
+  BaseNode &EmitExpr(SSATab&) override;
+  bool IsSameVariableValue(const VarMeExpr&) const override;
+  ScalarMeExpr *FindDefByStmt(std::set<ScalarMeExpr*> &visited);
+
  private:
   OriginalSt *ost;
   uint32 vstIdx;    // the index in MEOptimizer's VersionStTable, 0 if not in VersionStTable
@@ -307,6 +326,8 @@ class ScalarMeExpr : public MeExpr {
   } def;
 };
 
+using RegMeExpr = ScalarMeExpr;
+
 // represant dread
 class VarMeExpr final : public ScalarMeExpr {
  public:
@@ -453,35 +474,6 @@ class MePhiNode {
   bool isPiAdded = false;
 };
 
-class RegMeExpr : public ScalarMeExpr {
- public:
-  RegMeExpr(int32 exprid, OriginalSt *ost, uint32 vidx, PrimType ptyp)
-      : ScalarMeExpr(exprid, ost, vidx, kMeOpReg, OP_regread, ptyp),
-        regIdx(ost->GetPregIdx()) {}
-
-  ~RegMeExpr() = default;
-
-  void Dump(const IRMap*, int32 indent = 0) const override;
-  BaseNode &EmitExpr(SSATab&) override;
-  bool IsSameVariableValue(const VarMeExpr&) const override;
-  RegMeExpr *FindDefByStmt(std::set<RegMeExpr*> &visited);
-
-  PregIdx16 GetRegIdx() const {
-    return regIdx;
-  }
-
-  void SetRegIdx(PregIdx16 regIdxVal) {
-    regIdx = regIdxVal;
-  }
-
-  bool IsNormalReg() const {
-    return regIdx >= 0;
-  }
-
- private:
-  PregIdx16 regIdx;
-};
-
 class ConstMeExpr : public MeExpr {
  public:
   ConstMeExpr(int32 exprID, MIRConst *constValParam, PrimType t)
diff --git a/src/mapleall/maple_me/src/irmap.cpp b/src/mapleall/maple_me/src/irmap.cpp
index f0417e0cd116ea9d18b6d02bb15c05ee97d1023a..61421acfd32e6a7865516bcdcab9a5c18792a841 100644
--- a/src/mapleall/maple_me/src/irmap.cpp
+++ b/src/mapleall/maple_me/src/irmap.cpp
@@ -105,12 +105,12 @@ VarMeExpr *IRMap::CreateNewLocalRefVarTmp(GStrIdx strIdx, TyIdx tIdx) {
 }
 
 RegMeExpr *IRMap::CreateRegMeExprVersion(OriginalSt &pregOSt) {
-  auto *regReadExpr = New<RegMeExpr>(exprID++, &pregOSt, 0, pregOSt.GetMIRPreg()->GetPrimType());
+  RegMeExpr *regReadExpr = New<RegMeExpr>(exprID++, &pregOSt, 0, kMeOpReg, OP_regread, pregOSt.GetMIRPreg()->GetPrimType());
   return regReadExpr;
 }
 
 RegMeExpr *IRMap::CreateRegMeExprVersion(const RegMeExpr &origExpr) {
-  auto *regReadExpr = New<RegMeExpr>(exprID++, origExpr.GetOst(), 0, origExpr.GetPrimType());
+  auto *regReadExpr = New<RegMeExpr>(exprID++, origExpr.GetOst(), 0, kMeOpReg, OP_regread, origExpr.GetPrimType());
   return regReadExpr;
 }
 
@@ -126,7 +126,7 @@ RegMeExpr *IRMap::CreateRefRegMeExpr(const MIRSymbol &mirSt) {
     preg->SetNeedRC();
   }
   OriginalSt *oSt = ssaTab.GetOriginalStTable().CreatePregOriginalSt(regIdx, mirFunc->GetPuidx());
-  auto *regreadexpr = New<RegMeExpr>(exprID++, oSt, 0, pType);
+  auto *regreadexpr = New<RegMeExpr>(exprID++, oSt, 0, kMeOpReg, OP_regread, pType);
   return regreadexpr;
 }
 
@@ -135,7 +135,7 @@ RegMeExpr *IRMap::CreateRegMeExpr(PrimType pType) {
   PregIdx regIdx = mirFunc->GetPregTab()->CreatePreg(pType);
   ASSERT(regIdx <= 0xffff, "register oversized");
   OriginalSt *ost = ssaTab.GetOriginalStTable().CreatePregOriginalSt(regIdx, mirFunc->GetPuidx());
-  auto *regReadExpr = New<RegMeExpr>(exprID++, ost, 0, pType);
+  auto *regReadExpr = New<RegMeExpr>(exprID++, ost, 0, kMeOpReg, OP_regread, pType);
   return regReadExpr;
 }
 
@@ -144,7 +144,7 @@ RegMeExpr *IRMap::CreateRegRefMeExpr(MIRType &mirType) {
   PregIdx regIdx = mirFunc->GetPregTab()->CreatePreg(PTY_ref, &mirType);
   ASSERT(regIdx <= 0xffff, "register oversized");
   OriginalSt *ost = ssaTab.GetOriginalStTable().CreatePregOriginalSt(regIdx, mirFunc->GetPuidx());
-  auto *regReadExpr = New<RegMeExpr>(exprID++, ost, 0, mirType.GetPrimType());
+  auto *regReadExpr = New<RegMeExpr>(exprID++, ost, 0, kMeOpReg, OP_regread, mirType.GetPrimType());
   return regReadExpr;
 }
 
diff --git a/src/mapleall/maple_me/src/irmap_build.cpp b/src/mapleall/maple_me/src/irmap_build.cpp
index 5633fce7f3d22603ee0731e4f8e76768182d7c33..990e77f31c910756732a0ca649f0acc2bdad0113 100644
--- a/src/mapleall/maple_me/src/irmap_build.cpp
+++ b/src/mapleall/maple_me/src/irmap_build.cpp
@@ -48,7 +48,8 @@ RegMeExpr *IRMapBuild::GetOrCreateRegFromVerSt(VersionSt &vst) {
   }
   OriginalSt *ost = vst.GetOst();
   ASSERT(ost->IsPregOst(), "GetOrCreateRegFromVerSt: PregOST expected");
-  auto *regx = irMap->New<RegMeExpr>(irMap->exprID++, ost, vindex, ost->GetMIRPreg()->GetPrimType());
+  auto *regx = irMap->New<RegMeExpr>(irMap->exprID++,
+                                     ost, vindex, kMeOpReg, OP_regread, ost->GetMIRPreg()->GetPrimType());
   irMap->vst2MeExprTable[vindex] = regx;
   return regx;
 }
diff --git a/src/mapleall/maple_me/src/irmap_emit.cpp b/src/mapleall/maple_me/src/irmap_emit.cpp
index 9dba09cddee63bf4dd6166e02787fc573d1aaba5..b4dd5d3668cb9589079daeb8e20ef3269d33fbec 100644
--- a/src/mapleall/maple_me/src/irmap_emit.cpp
+++ b/src/mapleall/maple_me/src/irmap_emit.cpp
@@ -43,9 +43,9 @@ BaseNode &VarMeExpr::EmitExpr(SSATab &ssaTab) {
 BaseNode &RegMeExpr::EmitExpr(SSATab &ssaTab) {
   auto *regRead = ssaTab.GetModule().CurFunction()->GetCodeMemPool()->New<RegreadNode>();
   regRead->SetPrimType(GetPrimType());
-  regRead->SetRegIdx(regIdx);
-  ASSERT(regIdx < 0 ||
-         static_cast<uint32>(static_cast<int32>(regIdx)) < ssaTab.GetModule().CurFunction()->GetPregTab()->Size(),
+  regRead->SetRegIdx(GetRegIdx());
+  ASSERT(GetRegIdx() < 0 ||
+         static_cast<uint32>(static_cast<int32>(GetRegIdx())) < ssaTab.GetModule().CurFunction()->GetPregTab()->Size(),
          "RegMeExpr::EmitExpr: pregIdx exceeds preg table size");
   return *regRead;
 }
diff --git a/src/mapleall/maple_me/src/me_ir.cpp b/src/mapleall/maple_me/src/me_ir.cpp
index 98b47bea47cf28e17c8eaa21b263af1b67229af4..d3655ab9e191144a87953de2963310e927270845 100644
--- a/src/mapleall/maple_me/src/me_ir.cpp
+++ b/src/mapleall/maple_me/src/me_ir.cpp
@@ -759,10 +759,10 @@ void VarMeExpr::Dump(const IRMap *irMap, int32) const {
 
 void RegMeExpr::Dump(const IRMap *irMap, int32) const {
   CHECK_NULL_FATAL(irMap);
-  LogInfo::MapleLogger() << "REGINDX:" << regIdx;
+  LogInfo::MapleLogger() << "REGINDX:" << GetRegIdx();
   LogInfo::MapleLogger()
       << " %"
-      << irMap->GetMIRModule().CurFunction()->GetPregTab()->PregFromPregIdx(static_cast<PregIdx>(regIdx))->GetPregNo();
+      << irMap->GetMIRModule().CurFunction()->GetPregTab()->PregFromPregIdx(static_cast<PregIdx>(GetRegIdx()))->GetPregNo();
   LogInfo::MapleLogger() << " mx" << GetExprID();
 }
 
diff --git a/src/mapleall/maple_me/src/preg_renamer.cpp b/src/mapleall/maple_me/src/preg_renamer.cpp
index efae88d8dc4bd9c9a5d6f34dae5046965c1a3d5c..b908f9b33697511c114fecb7547ab0fdcfa739d0 100644
--- a/src/mapleall/maple_me/src/preg_renamer.cpp
+++ b/src/mapleall/maple_me/src/preg_renamer.cpp
@@ -33,7 +33,7 @@ void PregRenamer::RunSelf() {
     }
     MapleMap<OStIdx, MePhiNode *> &mePhiList =  bb->GetMePhiList();
     for (auto it = mePhiList.begin(); it != mePhiList.end(); ++it) {
-      OriginalSt *ost = func->GetMeSSATab()->GetOriginalStFromID(it->first);
+      OriginalSt *ost = func->GetMeSSATab()->GetOriginalStTable().GetOriginalStFromID(it->first);
       if (!ost->IsPregOst()) { // only handle reg phi
         continue;
       }
@@ -92,6 +92,7 @@ void PregRenamer::RunSelf() {
       continue;
     }
     newpregidx = pregtab->ClonePreg(*pregtab->PregFromPregIdx(regMeexpr->GetRegIdx()));
+    OriginalSt *newost = func->GetMeSSATab()->GetOriginalStTable().CreatePregOriginalSt(newpregidx, func->GetMirFunc()->GetPuidx());
     renameCount++;
     if (DEBUGFUNC(func)) {
       LogInfo::MapleLogger() << "%" << pregtab->PregFromPregIdx(regMeexpr->GetRegIdx())->GetPregNo();
@@ -100,7 +101,7 @@ void PregRenamer::RunSelf() {
     // reneme all the register
     for (uint32 i = 0; i < vec.size(); ++i) {
       RegMeExpr *canregnode =  static_cast<RegMeExpr *> (regmeexprtable[vec[i]]);
-      canregnode->SetRegIdx(newpregidx);  // rename it to a new register
+      canregnode->SetOst(newost);  // rename it to a new register
     }
   }
 }