diff --git a/src/mapleall/maple_me/include/me_bb_layout.h b/src/mapleall/maple_me/include/me_bb_layout.h
index 6a8369587abbd20140d7cfa5ab0ec7a51ec6f8a8..4a5815fbf2a08b706b28d15b4ce8cf9482dba411 100644
--- a/src/mapleall/maple_me/include/me_bb_layout.h
+++ b/src/mapleall/maple_me/include/me_bb_layout.h
@@ -70,6 +70,8 @@ class BBLayout{
   BB *CreateGotoBBAfterCondBB(BB &bb, BB &fallthru);
   bool ChooseTargetAsFallthru(const BB &bb, const BB &targetBB, const BB &oldFallThru,
                               const BB &fallThru) const;
+  void ChangeToFallthruFromCondGoto(BB &bb);
+  void OptimizeEmptyFallThruBB(BB &bb);
   const MapleVector<BB*> &GetBBs() const {
     return layoutBBs;
   }
diff --git a/src/mapleall/maple_me/src/me_bb_layout.cpp b/src/mapleall/maple_me/src/me_bb_layout.cpp
index 3125b26bd9573088edc58fc4bf0c08f24ca13f60..b37d54a67f9d3eca00668e71ecd144027dff9fdd 100644
--- a/src/mapleall/maple_me/src/me_bb_layout.cpp
+++ b/src/mapleall/maple_me/src/me_bb_layout.cpp
@@ -298,6 +298,7 @@ void BBLayout::OptimizeBranchTarget(BB &bb) {
   do {
     ASSERT(!bb.GetSucc().empty(), "container check");
     BB *brTargetBB = bb.GetKind() == kBBCondGoto ? bb.GetSucc().back() : bb.GetSucc().front();
+    CHECK_FATAL((bb.GetKind() != kBBCondGoto || bb.GetSucc().back() != bb.GetSucc().front()), "target is same as fallthru");
     if (brTargetBB->GetAttributes(kBBAttrWontExit)) {
       return;
     }
@@ -449,6 +450,16 @@ void BBLayout::ChangeToFallthruFromGoto(BB &bb) {
   bb.SetKind(kBBFallthru);
 }
 
+void BBLayout::ChangeToFallthruFromCondGoto(BB &bb) {
+  ASSERT(bb.GetKind() == kBBCondGoto, "ChangeToFallthruFromCondGoto: unexpected BB kind");
+  if (func.GetIRMap() != nullptr) {
+    bb.RemoveMeStmt(to_ptr(bb.GetMeStmts().rbegin()));
+  } else {
+    bb.RemoveLastStmt();
+  }
+  bb.SetKind(kBBFallthru);
+}
+
 // bb does not end with a branch statement; if its fallthru is not nextBB,
 // perform the fix by either laying out the fallthru immediately or adding a goto
 void BBLayout::ResolveUnconditionalFallThru(BB &bb, BB &nextBB) {
@@ -643,6 +654,23 @@ BB *BBLayout::CreateGotoBBAfterCondBB(BB &bb, BB &fallthru) {
   return newFallthru;
 }
 
+void BBLayout::OptimizeEmptyFallThruBB(BB &bb) {
+  if (needDealWithTryBB) { return; }
+  auto *fallthru = bb.GetSucc().front();
+  if (fallthru && fallthru->GetBBLabel() == 0 &&
+      (BBEmptyAndFallthru(*fallthru) || BBContainsOnlyGoto(*fallthru))) {
+    if (fallthru->GetSucc().front() == bb.GetSucc().back()) {
+      bb.ReplaceSucc(fallthru, bb.GetSucc().back());
+      ASSERT(fallthru->GetPred().empty(), "fallthru should not has other pred");
+      ChangeToFallthruFromCondGoto(bb);
+      bb.GetSucc().pop_back(); // resize succ to 1
+      laidOut[fallthru->GetBBId()] = true;
+      RemoveUnreachable(*fallthru);
+    }
+  }
+  return;
+}
+
 void BBLayout::DumpBBPhyOrder() const {
   LogInfo::MapleLogger() << func.GetName() << " final BB order " <<  '\n';
   for (auto bb : layoutBBs) {
@@ -663,6 +691,16 @@ void BBLayout::OptimiseCFG() {
     auto *bb = *bIt;
     if (bb->GetKind() == kBBCondGoto || bb->GetKind() == kBBGoto) {
       OptimizeBranchTarget(*bb);
+      // check fallthru is empty without label, delete fallthru and
+      // make fallthrSucc as the only succ of bb
+      //      bb
+      //      /      \
+      //   fallthru  |
+      //      \      /
+      //      fallthruSucc
+      if (bb->GetKind() == kBBCondGoto) {
+        OptimizeEmptyFallThruBB(*bb);
+      }
     }
   }
   cfg->UnreachCodeAnalysis(true);
@@ -795,15 +833,14 @@ void BBLayout::AddBBProf(BB &bb) {
     BB *targetBB = curBB->GetSucc().front();
     if (curBB->GetKind() == kBBFallthru && (&bb != targetBB)) {
       CreateGoto(*curBB, func, *targetBB);
-    }
-    if (curBB->GetKind() == kBBGoto && (&bb == targetBB)) {
+    } else if (curBB->GetKind() == kBBGoto && (&bb == targetBB)) {
       // delete the goto stmt
       ChangeToFallthruFromGoto(*curBB);
     }
-  }
-  if (curBB->GetKind() == kBBCondGoto) {
+  } else if (curBB->GetKind() == kBBCondGoto) {
     BB *fallthru = curBB->GetSucc(0);
     BB *targetBB = curBB->GetSucc(1);
+    CHECK_FATAL(targetBB != fallthru, "condbb targetBB is same as fallthru");
     if (targetBB == &bb) {
       LabelIdx fallthruLabel = func.GetOrCreateBBLabel(*fallthru);
       if (func.GetIRMap() != nullptr) {